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I started wanting “the baddest Mini in northern Nevada” and finished with possibly the baddest street-able R56 in the country. I gotta admit, the claim is for dyno numbers only (charts are in the journal), not practical use on the strip, track or street. Some of the mods are not compatible with each other, and would cause grief with many other drivers. It was built to be a “sleeper” —- all kinds of fun on the streets. It’s something I can get away with being located in northern NV —- rural, small town living (2 traffic lights), ½ hour from the nearest big city, and ¼ mile from U.S. 50, the loneliest hiway in the country.
Not sure which was the biggest problem, probably too high a CR (10.5:1) for the 30PSI boost limit. I hoped the CP Carrillo pistons and rods could handle it. They did for awhile —- I got over two years of 28 - 30 PSI max with no issues. However, this boost level was seldom used. Most of my driving is close to speed limits, and very little hard acceleration. With 360 WHP available, you don’t need a lot of gas pedal to get around. Plus, a long time ago, I did 3 days in L.A. county jail for “speed contest” —- not gonna happen again!
When the engine “let go”, I was at the Sacramento, CA drag strip, half way thru my 2nd run. I was expecting better numbers for the 1st run. Hopefully they’re low because part failure had already started. I was hoping for a couple good runs at a sea-level strip to compare with my local strip at 4K’. Not gonna happen for awhile. I have terrible reaction time —- that’s me, not the car. The ET is low because there’s also terrible launch capability —- a light flywheel and slow-spooling turbo results in not enough inertia to get moving quickly. Even slipping the clutch and an unlimited launch RPM doesn’t help. This was a good combination for keeping me out of jail, and saved a bunch on tires and axels, but lousy for the drag strip.
One interesting discovery —- the 3” exhaust pipe doesn’t clear the frame under hard acceleration. Notice the pipe kink where it hits the frame during “engine roll”, or torque. Gotta fix that when installing the next turbo. https://www.northamericanmotoring.co...9&d=1471559945
Then #2 piston. There was also aluminum “residue” on top of rod #2 —- apparently from the blown-out piston. Didn’t get a pic before I cleaned up most of it. Wrist pin and rod bushing also took a hit. https://www.northamericanmotoring.co...2&d=1471560149
Pic doesn’t show it clearly, but all 5 of the intake cam journals, cam, and caps are scored. Plus the cam has one of the two interlocking rings broken —- the rings that fit inside the vanos unit. The ring might be replaceable but the journals need to be machined. If machined, they wouldn’t fit the head without building up the 5 journals, then line-boring it to accept the machined cam. Not practical! No damage to the exhaust cam or its journals. https://www.northamericanmotoring.co...4&d=1471560235
Did a partial tear-down on the Garrett and convinced myself that the bearings found in the oil pan came from the turbo. Turbo also has a slight amount of end-to-end shaft play, so it’s on the “replace” list, not repair. Have no clue how / why the bearing failed. It was performing nice up until the engine blew.
So, now to rebuild. All 4 rods are out for new bushings, #2 clean-up, then all 4 to be balanced.
Looking at Schrick and Cat cams, Borg Warner EFR 6258 or 6758 turbo, 9.5:1CR and 77.5mm CP pistons (notched for a hi-lift cam), working with a local indy shop to machine the next block, and working with Thumper again for a replacement head.
I’m posting all this in the hopes that someone will learn from my mistakes, and not make the same ones. I purposely went with the 10.5:1CR pistons, even tho popular opinion was “that’s too high for 30PSI boost”. My “heyday” was before turbos were common, and lowering CR was unthinkable. An expensive lesson learned! And 5 years ago, when I got the Garrett, there were only a couple JCW hybrids available (that I could find) —- nowhere near the capability I wanted.
Edit: Still gotta figure out how to show pics with text, not as thumbnails. Sorry 'bout that ---
Damn! Sorry to hear this news OBW. Are you considering Darton MID sleeves for the next one?
Hadn't really thought about sleeves. So far, plans are to get a bare block, bore to 77.5mm, and install CP 9.5:1CR pistons --- notched for a hi-lift cam. I'm hoping my original choice of 10.5:1CR pistons was the cause of this failure. Last build lasted 2+ years, this one should get me a couple more. I'll also turn down the MBC a few PSI.
The reason I asked about the sleeves is because I don't think your choice of 10.5:1 pistons was the direct cause of the failure. From what I can see on the pictures the top of your pistons don't show any evidence of detonation. A close examination of the piston crown, outer edge and combustion chamber roof would show for sure though. Yes the CR would typically be considered high for 30 psi but high methanol concentrations and a good tune can compensate a great deal. But I don't believe that even those can compensate for extremely high cylinder pressures on an open deck block.
Again I'm just going off of the pictures but based on my experience in fault analysis and even some accident investigation in aviation it appears as if a stress fracture of the cylinder wall is what lead to the failure. Cylinder pressures are by far the highest in the top 1/2" of the cylinder and drop exponentially the further down you go. The cylinder walls are subject to cyclic stress from the pressures generated during ignition and thermal cycling. Sometimes when I think about it that way it amazes me that engines stay together at all. It looks as if the stress fracture allowed the super heated gas to pass around the compression ring and began damaging the side of the piston. At the same time once the super heated gases began passing through the crack the sharp raised edges from the grain of the cylinder wall acted as heat risers focusing the heat, opening it further and it eventually just blow torched it's way though.
Would dropping the compression by helpful. I would have to say yes. Not counting the effects of valve overlap or variable valve timing your effective compression ration at 30 psi with 10.5:1 pistons at your usual altitude of 4000 ft is around 17.5:1. Driving down to sea level raises that to about 18.3:1 and those are getting into some pretty high numbers. Dropping your static compression to 9.5:1 reduces those numbers to 15.8:1 and 16.6:1 respectively. Nonetheless, I think the stock Mini open deck block just isn't up to handling the kind of numbers your beast was putting out. Not for lack of trying though. I have to give the old gal that. I've seen pictures of some WRX semi closed deck blocks that failed at 22 psi.
There are some companies that can machine an aluminum insert to support the top 1/2 inch or so of the cylinder which are placed in liquid nitrogen then pressed into place. This effectively closes the deck but includes passages for coolant to pass through. If I remember correctly Steven_RW used CNCWerx to close his deck. Not sure what the costs were. The other option is the Darton MID sleeves I mentioned which requires more extensive machining but completely replaces the factory cylinders altogether. I'm sure its more expensive as the sleeves are about $1,300 then there is the machine work to install them and true the deck afterwards. The advantage is that they are new sleeves that can be bored to 77 mm to begin with, leaving material for boring 0.020" over down the road should the need arise. I'm sure your next build will be a beast whatever you decide to do but thought this might be useful food for thought. Below is a pic of the final product with the Darton sleeves.
Last edited by Tigger2011; 08-20-2016 at 06:08 PM.
Sounds like I should take some of my dead parts in for a local professional's evaluation --- stress fracture or detonation. First, I gotta find one in my area. I'll talk to my CP Carrillo supplier, maybe they can help.
Tigger2011, you're the 2nd person suggesting a "cylinder support system" as CNCWerx calls it. First thought was no, they're on the wrong end of the country and will take too much time. Seems finding appropriate replacement parts with reasonable delivery times is tougher than I thought. I might just have time to send the block to the east coast, before other needed parts arrive. I should give them a call for more info. Advertised price is far less than Darton's. I'll check with Steven_RW also --- we've communicated before.
I sincerely appreciate your informal evaluation. I can build and drive but have no clue about failure analysis --- thanx.
Last edited by oldbrokenwind; 08-21-2016 at 02:47 PM.
Ive, been cc-ing and polishing the head chambers to get an actual target comp ratio, and to smooth the flow still keeping 10.5 pistons going for 9.5 but Im thinking dish might be ok too for a more even distribution at all out pressures. as for open block,,, ok closing it up would be stronger but also I deck the blocks just a skim and cooling Ive added an Arduino switch to keep temps to 180, not sure of soot build up but it seems happier and I think this goes towards keeping the head from leaking, or lifting which can cause burn out as well.
There was a build that went with larger APR studs.
Oh look at the ratios make a chart vs chamber size, A ratio before any carbon build up is not the same later but at higher ratios on turbos this can be deadly you do look as clean as can be expected though some extra room is a good idea to counter act the inevitable
Last edited by Euler-Spiral; 08-21-2016 at 08:24 AM.
Back to the turbo, once the piston stopped sealing blow-by would be through the roof. Turbo bearings drain directly into the case and need low pressure to have proper oil flow supposedly, its still a pressure in feed, Anyway at full spool if oil flow got disrupted even for a moment its goodby bearing
Ive, been cc-ing and polishing the head chambers to get an actual target comp ratio, and to smooth the flow still keeping 10.5 pistons going for 9.5 but Im thinking dish might be ok too for a more even distribution at all out pressures. as for open block,,, ok closing it up would be stronger but also I deck the blocks just a skim and cooling Ive added an Arduino switch to keep temps to 180, not sure of soot build up but it seems happier and I think this goes towards keeping the head from leaking, or lifting which can cause burn out as well.
There was a build that went with larger APR studs.
Oh look at the ratios make a chart vs chamber size, A ratio before any carbon build up is not the same later but at higher ratios on turbos this can be deadly you do look as clean as can be expected though some extra room is a good idea to counter act the inevitable
I'm sure that all this is excellent advice, however, at my level of expertise, it's way over my head. I understand the concepts of what you're explaining, but I can't begin to implement it. Trial and error has worked pretty good for me --- up until this fiasco. I plan on talking with Steven_RW, who also used big studs. Seems he's done what's being recommended here.
Originally Posted by Euler-Spiral
Can you get the block fluxed if its a crack it should continue past the burn out. Right at that spot is where I see the blocks low sometimes
No more funds going to the dead block --- it's trash! Ideally, I would have "skimmed" the surface when it was rebuilt --- head too. I plan on ensuring flat mating surfaces on both for this next build.
Originally Posted by Euler-Spiral
Back to the turbo, once the piston stopped sealing blow-by would be through the roof. Turbo bearings drain directly into the case and need low pressure to have proper oil flow supposedly, its still a pressure in feed, Anyway at full spool if oil flow got disrupted even for a moment its goodby bearing
Pretty sure there was enough blow-by to slow the oil flow, as evidenced by my "PCV issues" --- oil in the turbo air inlet chamber. Should of done compression tests more often --- hazards of excess power --- can't recognize a failing cylinder. I did a tear-down on the CHRA. Found only one bearing race, where two are advertised --- again, lack of experience with turbos, so I'm not positive this is a problem. I don't have the know-how or tools to put it back together, so gonna work with a turbo re-builder for another CHRA, or replace the whole turbo with a smaller unit --- something with less lag --- TBD. Slow-to-spool saves axels and tires, just causes anxiety and lousy drag-strip time slips.
Last edited by oldbrokenwind; 08-21-2016 at 02:48 PM.
I dont think this was a maintenance issue, it all happens in a split second just amazing the engine came out as good as it did in the end so you did things well. Its just a hard learning curve. The newer turbos are better all around, size is a bit less of an issue just need the flow path to match, and that needs custom intakes and exhaust.
You can CC the heads at home or a shop already doing work for you shouldnt charge too much
I replied to your pm. The following is just my opinion.
The chat about no visible detonation on top of the piston meaning 10.5:1 isn't your issue isn't accurate. Two types of det. Heat related det (too high inlet temps and running lean etc) makes for pitting on top of piston and melted spark plug tips. Standard detonation through too much compression for the fuel type and the power goes down the side of the piston and melts between the piston skirt and the bore in a kinda hammering shockwave.
If you want to continue on standard fuel at 360bhp with confidence you could actually hold it flat out you need lower than 9.5:1 as well. We are on 8.0:1 cp pistons. You don't lose response. You gain safety in your det margin.
I'm entirely supportive just short on time to type it all up.
Jeff from cnc werx to close your block deck and some really good head studs and a realistic compression ratio for that much power on std fuel. Just look at where Peugeot reduced the compression ratio to on the rcz-r which has to be factory reliable for 270bhp. Less than you are going to spec for your new build. Their development budget is millions and they went that way.
Cheers and direct anything you think I can help with via pm as it will get my attention. I've forwarded this thread to my engine tuner who may have an opinion too. Thanks
I replied to your pm. The following is just my opinion.
The chat about no visible detonation on top of the piston meaning 10.5:1 isn't your issue isn't accurate. Two types of det. Heat related det (too high inlet temps wrong timing or running lean etc) makes for pitting on top of piston and melted spark plug tips. Standard detonation through too much compression for the fuel type and the power goes down the side of the piston and melts between the piston skirt and the bore in a kinda hammering shockwave.
If you want to continue on standard fuel at 360bhp with confidence you could actually hold it flat out you need lower than 9.5:1 as well. We are on 8.0:1 cp pistons. You don't lose response. You gain safety in your det margin.
I'm entirely supportive just short on time to type it all up.
Jeff from cnc werx to close your block deck and some really good head studs and a realistic compression ratio for that much power on std fuel. Just look at where Peugeot reduced the compression ratio to on the rcz-r which has to be factory reliable for 270bhp. Less than you are going to spec for your new build. Their development budget is millions and they went that way.
Cheers and direct anything you think I can help with via pm as it will get my attention. I've forwarded this thread to my engine tuner who may have an opinion too. Thanks
with direct injection and proper intercooling and or water meth 400whp should be do-able into the 9.+ area, the only reason though is to maintain efficiency in lean mode or while intake is in vacuum not boost, this can be a way to get flow up before boosting. Heat is always the issue detonation can happen very early with hot spots on port injection but with DI there is no fuel yet. Peugeot would have needed to leave an extra margin for carbon buildup.
8.0 is high for heavy boost on port injection but fine for DI and would allow aggressive timing and fuel profiles, and yes safer to a point, How early and hard do you want your boost, you could set boost curves that will eat up any safety margin these days as turbos are very flexible now.
I like a progressive boost light at 2500 rpm but by 3000 rpm spiking a bit then steady rise to redline it matches my needs for cornering Im not much for off the line starts though.
equally important is getting good vacuum and minimizing boost pressures by porting and tuning intakes and exhaust,
look how the new engines have the bloody exhaust manifold integrated into the head to get a bit more energy to the turbo, Knock profiles also play an important role as adaptive ECU code can fine tune on the go.
with direct injection and proper intercooling and or water meth 400whp should be do-able into the 9.+ area, the only reason though is to maintain efficiency in lean mode or while intake is in vacuum not boost, this can be a way to get flow up before boosting. Heat is always the issue detonation can happen very early with hot spots on port injection but with DI there is no fuel yet. Peugeot would have needed to leave an extra margin for carbon buildup.
8.0 is high for heavy boost on port injection but fine for DI and would allow aggressive timing and fuel profiles, and yes safer to a point, How early and hard do you want your boost, you could set boost curves that will eat up any safety margin these days as turbos are very flexible now.
I like a progressive boost light at 2500 rpm but by 3000 rpm spiking a bit then steady rise to redline it matches my needs for cornering Im not much for off the line starts though.
equally important is getting good vacuum and minimizing boost pressures by porting and tuning intakes and exhaust,
look how the new engines have the bloody exhaust manifold integrated into the head to get a bit more energy to the turbo, Knock profiles also play an important role as adaptive ECU code can fine tune on the go.
Not looking to disagree with anyone, just sharing my views.
Hi. We added three degrees timing across the map when we reduced the compression ratio. On a before and after test the increased timing advance made the boost come in slower but once the boost was in the power was better in all areas. So timing is key to bringing in the turbo too.
Speaking to the OP I don't believe his car saw large extended periods of WOT (similar to say a runway race event). I think this failure would have happened much sooner if the engine did see extended WOT. I'd always want to build an engine that I knew could handle most any amount of usage I threw at it, based on its build and tune etc. So I prefer the lower compression. I have graphs on 10.5:1 and graphs on 8.0:1 the response difference is utterly minimal but I am confident it has more chance of surviving heavy hard usage in comparison to 10.0:1.
Regarding decking the block. When Jeff returns your block (very speedy turn around btw... I had it leave the UK, get worked on and back to the UK within 2 weeks, including all the crazy borders and customs challenges) you will need to skim/deck it as the CSS sits proud.
The absolute minimum I'd use is the off the shelf ARP stud and nut 10mm kit. We went for a bespoke 12mm ARP stud n nut kit. Clamping the head thoroughly to the block.
If you aren't using the mini for high speeds then a smaller turbo that makes your car more useful in the area you use it would maybe be a good idea. We are doing cool stuff with our turbo at the moment to try and free it up a bit without risk of extra lag.
Last comment, our experience agrees that DI allowed you to run higher compression for the power than we expected or experienced previously. We are about to add 4 extra port injectors to increase our fuelling limit so our car effectively becomes port injection again.. 8.0:1 is as high as we are willing to risk.
Hi Steven I know you youve got this down, yes timing is about getting a larger charge into the chambers so is always good. Its perhaps a crazy goal to try and build a track/street car, every step you take towards a track/race car makes use on the street less livable, Its the super lean mode that needs the higher compression. I get 350-ish ft-lb and 320ish hp using my oh so accurate logging runs, they came close to what friends get on the dyno.
Anyway I also can still get 40mph on the flat with a super light foot (a light tail wind never hurts) and can feather in some boost and hold it, Its just crazy not quite possible for my brain to get around. I can drive to a track day, wind it up and drive home. My Honda's boosted well at 5000 rpm went to almost 10,000 used massive injectors and were hard to get use of the power in the corners. and mileage about 15mpg
I have been planning a stripped down chopped back crazy build with some insane turbo and yes lower compression is on the list maybe not 8.0 but Ive been looking at the injectors and ????? on Bosch motor sport they say the DI injectors go to 1000 cc which seems ok with the high pressure so Ive been wondering if they have different injectors or its in the ECU code or on the injector's circuit, there are the audi injectors that have been used in N14 despite a bit different spray pattern, Anyway it should be possible to get or mod DI injectors for more fuel.
Oh then there is the whole throttle response set up which I basically throw my hands up and give up on, Its kind of maybe the most important thing of all as it can change depending on how you hit the throttle if you log vs throttle angle you know what Im talking about there is this one tap/foot/push that can turn boost on full when I dont want it.
Ok so there is too much for a quick post, Most of this would be easier if we used an open ECU,,,,,,,AHHHHHHHHH IMMMMMM STTTTopppppingggg now
The point about timing was ignition timing. Running advance usually makes the combustion more efficient. The point was that by running more advance before boost threshold the boost threshold moved up the RPM scale. I can only assume that running it with less advance makes for more exhaust gas or more of the combustion process occurring in the exhaust manifold. Spinning up the turbo earlier. As soon as it hits boost the extra advance is fine as it creates more power and the turbo is already self feeding in it's cycle by that time. More boost more exhaust gas making more boost and so on.
Yes lower comp gives less fuel economy. I'd still rather have a safer engine at WOT than a few extra MPG.
Like you say, the fact we can't control this ECU perfectly makes for large compromises. We aren't moving on to other DI injectors at this point. If we had some way of really controlling the ECU, maybe that is a good idea but right now, it feels better to stick with stuff we know rather than investing loads into this DI system only to find we can't ask it to do what we want.
Would be good to hear what OBW is thinking about his next steps. :-)
Hi Sorry OldBrokenWind. Yes what are you thinking for the new engine?
Ok just one last thing,,,, OH NO,,,,,,, (my alternative is working on my bathroom project) ,,,,, PLease forgive me.
I do think more of cam timing, but kind of group the two together along with the knock profile. The way I work through thinking about the whole ignition thing is to go at super slow motion. The actual burn is fast but not instantaneous and the piston is moving all the time. Compression changes the charge burn shape or profile and where we get our full dynamic force in the piston cycle can move, So nothing new and the whole charge should burn, but if you get it timed earlier you get a bit more power mechanically and a little reaction wise unless you are very late ATDC. The thing is you can get a burn thats off, too hot wrong shape or speed thats what can be called detonation, But to some extent its always detonation, you now need to slow down even more way beyond what can be seen experimentally and build a model of the way the reactions are unfolding, this is where the Knock profiles start to come to play, we dont want destructive detonation even once but what clues we have are here and can be guessed at by frequencies related to combustion and these bits of code are not shared sadly, So you can advance a bit towards destruction blindly (ok you actually do look) but some setups can ride the wave (knock profiling), Now Add DI and you can shape a fast-ish fuel spray pattern like good old diesel but the fuel is way faster way less predictable we still need a spark, And your fuel will be mixing not mixed so it actually is sucking in some energy actually doing a bit of cooling well its not AC but an added complexity, So Shape from porting we can tune, piston profile tunable, how we want to slice up the cam timing is tunable, and a little of the ignition is tunable, but knock profile is still a bit out but should be doable,,,,,,,,, Also spray pattern and duration, So baking cookies is so relaxing after contemplating ignition
Oh right so earlier timing = more force on piston so faster rpms so faster to boost and a bit hotter exhaust,,,, so any-way non boost power can be built gets you to boost faster and allows harder boost, and bigger turbos, Think good naturally aspirated thoughts then add boost which gets back to comp ratio, no way around lower is safer I totally bow on that butt I must have all the cookies,,,, Im going off to do the bathroom project
I pledge to not go off on crazy posts for three days or until I bash a thumb
Oh right so earlier timing = more force on piston so faster rpms so faster to boost and a bit hotter exhaust,,,, so any-way non boost power can be built gets you to boost faster and allows harder boost, and bigger turbos,
Hi - my point earlier is that this was not what was experienced. LATER timing, IE less ignition advance resulted in the boost coming in earlier.
IE, static load dyno, full throttle at 2,500 rpm at 7 degrees timing = .7bar boost, say 100bhp at the wheels
same scenario at 10 degrees advance (no knock) = .2bar boost. say 70bhp at the wheels.
Huge difference. Driven by the boost the car could produce at that static RPM at WOT.
The retarded ignition timing resulted in more exhaust gas or "drive" for the exhaust turbine. As soon as boost arrived, the extra timing was beneficial.
Always fun to chat this stuff through. Can I ask where you learned all your info and if you have turned it into some fast cars? What turbo do you have that makes 320bhp as we can't get that much out of our turbo. What back pressure between turbo and exhaust ports (ie in the exhaust manifold)?
Hopefully OBW is reading all this and using it to keep motivated to make the fix! ~:-)
Cheers
Steven RW
Last edited by Steven_RW; 08-23-2016 at 08:03 AM.
Reason: Because I typed it all back to front... :-)
I'm still making decisions about what to do next. Called about a cylinder support system and re-bore for a used block I obtained --- they tell me I need to send a new piston so they know how much to bore --- gotta be their measurement. Before I order pistons, I gotta know valve lift, duration, etc. Been working with the only listed Cat Cams rep in the country, VAC Motorsports in PA (there's two, but the west coast guy only does Audi cam's). He tells me that Cat is starting production on the version I want (the middle rating of the 3 available) and I should be able to get a set in 3 - 4 weeks. Taking their word for it, I ordered a set, copied the tech info, and sent it to my local CP dealer to get a set of 77.5mm, 9.0:1CR pistons --- same guy getting my old Carrillo rods re-bushed. This dealer is a Porsche specialist, and also carries ARP hardware. I'll work with him to build a list of bolts for both crank and head (10mm, not 12). Carrillo rod bolts should still be OK. When the pistons arrive, then I can send the block and a piston to NH for the CSS and bore / deck surfacing --- up to a 4 week process.
That is what I've committed to, so far. Both Steven and Euler have presented some very informative and useful info. My decisions are based on that plus my own gut. I factored in parts availability, budget, spouse, my own limitations and desires --- all weighted very heavily, and came up with the above. No disrespect intended, but most of their discussion is at the automotive engineering level and way over my head. My education, both formal and informal (street), was substantial but directed elsewhere. I understand most of the above, but converting it to practical use --- forget it! I recognize results as much, if not more than theory. Having retired from the world of manufacturing quality assurance / control, I realize there's more than engineering to producing useable, reliable products.
Still gotta consider the turbo --- rebuild or replace the CHRA, or replace the whole unit with a slightly smaller one. But that decision's a couple months away.
I'm still making decisions about what to do next. Called about a cylinder support system and re-bore for a used block I obtained --- they tell me I need to send a new piston so they know how much to bore --- gotta be their measurement. Before I order pistons, I gotta know valve lift, duration, etc. Been working with the only listed Cat Cams rep in the country, VAC Motorsports in PA (there's two, but the west coast guy only does Audi cam's). He tells me that Cat is starting production on the version I want (the middle rating of the 3 available) and I should be able to get a set in 3 - 4 weeks. Taking their word for it, I ordered a set, copied the tech info, and sent it to my local CP dealer to get a set of 77.5mm, 9.0:1CR pistons --- same guy getting my old Carrillo rods re-bushed. This dealer is a Porsche specialist, and also carries ARP hardware. I'll work with him to build a list of bolts for both crank and head (10mm, not 12). Carrillo rod bolts should still be OK. When the pistons arrive, then I can send the block and a piston to NH for the CSS and bore / deck surfacing --- up to a 4 week process.
That is what I've committed to, so far. Both Steven and Euler have presented some very informative and useful info. My decisions are based on that plus my own gut. I factored in parts availability, budget, spouse, my own limitations and desires --- all weighted very heavily, and came up with the above. No disrespect intended, but most of their discussion is at the automotive engineering level and way over my head. My education, both formal and informal (street), was substantial but directed elsewhere. I understand most of the above, but converting it to practical use --- forget it! I recognize results as much, if not more than theory. Having retired from the world of manufacturing quality assurance / control, I realize there's more than engineering to producing useable, reliable products.
Still gotta consider the turbo --- rebuild or replace the CHRA, or replace the whole unit with a slightly smaller one. But that decision's a couple months away.
Obw: that all sounds good. Much better compression ratio. Going on pics alone the thoughts are your head lifted and the head gasket allowed leakage which destroyed your cylinder wall and then it compounded from there. Off the shelf arp at 10mm will do a fine job I'm sure. No engineer reboring a block will trust another engineers proposed measurement of a piston. They will always want to see it with their own eyes. New oil pump for your rebuild too. Carillo "CARR" rod bolts will easily do. You can get CP to give you an even more uprated piston pin whilst you are getting the new pistons. Just adds extra strength without too much extra weight. Not expensive upgrade if you order all in one from cp. Cp will give a guidance on bore clearance for the pistons. We put in more clearance than they suggested for extra margin. No oil burning issues so no regrets there. All sounds nice n positive. Stick at it! .
Ps I'm not wanting to discuss loads of tech theory I probably don't really understand either. Proof is in the eating of the pudding n all that. Cheers and good luck. SRW
Sounds like a solid well machined build sorry for being a bit over the edge. I do really like a good overall build rather than getting to much into just the engine I keep finding the gearbox is my stumbling point for more power anyway. I do think porting intakes exhaust and chamber help do ask for the head to be cc-ed so the comp ratio is as you want.
Sounds like a solid well machined build sorry for being a bit over the edge. I do really like a good overall build rather than getting to much into just the engine I keep finding the gearbox is my stumbling point for more power anyway. I do think porting intakes exhaust and chamber help do ask for the head to be cc-ed so the comp ratio is as you want.
Don't apologize for trying to educate me, it's good info! I enjoy a good discussion between enthusiasts.
Thanx for reminding me --- the head. Now that the cams have been decided on, I can proceed with the head replacement. I was holding off 'cause some cams require titanium retainers. Had I chosen one of these sets, I'd need to furnish the retainers to Thumper for the head I'm getting. My chosen cam set works with OEM springs and retainers --- a major factor in choosing this cam over the highest-lift version. Manic's recommendation (for my setup) too. I'll be furnishing SuperTech beehive springs, but OEM retainers. The head is to be Thumpers typical quality work, TPR-1, plus oversized intake and exhaust ports --- to duplicate the failed head --- failed intake cam journals, not Thumper's work. If the cam and it's journals hadn't failed, I probably wouldn't have gone with different cams. But, since I gotta replace a cam ---
As for measuring the chambers to ensure proper CR --- it's a bit late for that now, pistons are already ordered. And the gearbox --- axels are my biggest concern. I'm hoping the combination of Giken's light flywheel and a slow spooling turbo keep the stress to a minimum. It has so far. This is a major factor in deciding how to fix the turbo problem.
And Steven, I'd forgotten about the wrist pin option. I'll get that included in my order. I'm gonna try to flush the oil pump before replacing it. Speaking of bore clearance, I can remember on the big V-8's, using 0.010" clearance's on the 4"+ bores. CR's of 13 - 14 to 1, twin 4-barrels, ¾ cam, B & M tranny, 4.56 LSD --- memories!
Im sure Thumper isnt going to send a head thats not checked for cc's. Ive seen this cam stuff on the intake sides was wondering if the fuel pump plays some part. also our cam journal caps have no dowel's so drive me nuts.
regarding Stevens earlier post, At 2500 rpm I go for 0 psi (still its boost) and only curve up to 3000 rpm then steady upwards. 3000 rpm is a critical point I find, Power is a funny thing and torque seems more critical until say 4500 rpm. My Hondas went 500Hp then gearboxes and shafts and well lots of stuff had short lives but the engine's stayed together fine,,,,,
Late timing isnt so late have you watched what happens at idle almost no fuel and like 15-20 deg ATDC. Because we have small bore long stroke relative to rod length the point where maximum advantage is a bit later, as you add speed and fuel you need to compensate more. You could also be getting more cam timing but I think its fuel related if you were pushing more fuel timing would compensate more. have you noticed that wide open throttle isnt the same depending on how you push the throttle watch the pedal angle graph, engine off, ignition on, try foot about 2 inches off pedal then stomp, now try with foot starting on pedal, then just a regular push, you get different responses from the ECU especially in off boost. Also do you have sport mode?,,,,And there is adaptive code in there, I think more lambda related so I added a boost controller, still the off boost is ECU, so transition is a bit funny. I find I feel like I have to out think the throttle its not as connected as dual 40 Webers because the fueling follows flow in a natural response curve.
Ive been building cars since the 80's just on my own, I do design work and build stuff so it all runs together for me.
08-18-2016, 03:50 PM
