cool but it slices the crap outa your hand .!!! lol

 

it's been a while but i dont remember any big issues with location. cant hurt to mark and label for each cyl. wouldnt take long either. and if you're worried about thr rod journals you could always have the piston hanging down upside down and bolted loosly to crank so if you contact it'll be the rod not the journal . with the old bearing in place of course . you'll want to rotate the crank so the journal is at it's lowest point anyway . go slow and lots of oil . a cordless drill works best .

 

oh!!! be sure to pull ring up perpendicular or level with bore after checking end gap . just simulate the ring being on piston as you bring it up . one of mine flippped on me and i just pulled it up and presto!!! scratched bore . ouch !!

 

This is great advice, all. I thank you for your input.

I ordered a 240 grit flex-hone that should arrive for the weekend. I plan to give it a whirl on my electric drill.

At this point, I am planning to order the CP pistons.

In response to an earlier question: yes, I did kill a piston at 30k miles. Yes, I did change the oil frequently - every 2 or 3 track events. I imagine this was an issue of heat more than lubrication.

 

lubrication issues would show crank damage and bearing damage.. either by spinning a bearing or seizing the engine completely..

how does ur crank wear look? are there any scratches that u can catch a fingernail on? any blackening?

oil squirters are used to keep the pistons cooler, but lack of isn't going to cause catostrophic engine failure..and ur bearings would fail b4 ur piston would

I honestly don't see why u wouldn't take the engine out of the car..

just rent/buy an engine stand and cherry picker for awhile or even slap the engine on ur table..

u probably spend more time and effort and bloody knuckles by insisting on keeping it in the car, and crawling over/under/over/under rather then just pulling the long block slapping it on the stand and spinning it around on the stand.

i've overhauled several engines like this... without a problem


it's not worth the risk of another engine failure due to metal shavings in ur motor...

take the engine out.. tear it down properly and do it once and do it right... U can also port and polish ur head while ur at it.. or at least a gasket match+polish if u don't wanna go crazy


if ur rods and main bearings are ok, don't mix them up and re-use them

otherwise ur gonna have a royal PITA trying to plasti-gauge ur bearings while it's still in the car.

by using a pistol drill how can u insure even wear and distribution while u hone? in the video the brush and bore are the same size.. he just goes back and forth across it,, u'll have to go round and round and up and down.. at least u should have the Block on a Drill press while u do this with an appropriatly sized brush...

how bad is the damage to ur cyl walls? since ur geting CP pistons, perhaps u should consider having it overbored and cross hatched.. or re-sleeved..

honestly it almost looks like Detonation, u should check ur injectors flow rate, consider sending them off for cleaning and flow test perhaps..
if the cyl. was running lean, u'll end up repeating the same thing..
i've seen holes in racing pistons from detonation..

do u have a picture of ur spark plug from that cyl?

to me ur damage looks consistant with lean fuel conditions. especially where the piston "edge" melted and then took out the rings and u lost compression.

if u notice there's alot less carbon as well in teh damaged piston.. probably a) from running lean b) the pre-ignition "flashed" it off more then the others..

what were the conditions when ur engine failed?


sorry for the long post.. I have more to add. but I'll wait for ur reply first.

 

"honestly it almost looks like Detonation, u should check ur injectors flow rate, consider sending them off for cleaning and flow test perhaps..
if the cyl. was running lean, u'll end up repeating the same thing..
i've seen holes in racing pistons from detonation.. "

Yep... what he said!! Actually ALL of what he said!!

Going to the expense of the pistons rings.. might as well take an extra day and pull the engine and do it correct.. yes??

"if u notice there's alot less carbon as well in teh damaged piston.. probably a) from running lean b) the pre-ignition "flashed" it off more then the others..

what were the conditions when ur engine failed?"

I would be trying to find out WHY, you can put 10,000.00 worth of super trick pistons in there and if the problem persists.. you will break and melt those as well!! Just a thought..

Just me..................................

Thumper

 

No. The crank looks great.


I hear ya, and you make some really great points; however, you have to draw the line on a project like this somewhere.

My plan is to hone the cylinders with the block in place. I have pulled out the oil squirters and have clear access to the block. It's really like working with it on a stand. Obviously, it would be a lot easier to clean on with the crank out. I'm going to try putting down some plastic bags and oily rags and see how it goes.

If it turn into a mess, the engine is coming out!


I bought a 3 1/4" flex hone - slightly larger than the bore. I will go up and down - not round and round.

There is one tiny little scuff. I had a seasoned professional mechanic take a look, and he recommended honing it and moving on.

Sensational advice! I numbered the injectors and mailed them off Marren Injection today. I will absolutely publish the results when I get them back. I specifically stated that I wanted the "before results" that correspond with each injector. I numbered the injectors.

I think this is highly consistent with the lean injector idea. After running at a track event in April, the car was running a little rough at idle. I figured it would throw a CEL at any moment. It didn't. I went back to the track in mid-June. On day 2, I came in after a 25-minute session. The car had been running perfectly on the track. I pulled into the paddock, and it would barely idle. I let it cool off then restarted it - 3 cylinders only. It finally threw a CEL - P0301 for misfire in cylinder 1. I pulled the plugs in cylinders 1 & 2. #1 was covered in oil. #2 looked perfect.

A friend trailered the car home for me.

My question is: was the cylinder low on compression after the April event and that led to the rough idle or was there a clogged injector that was causing cylinder #1 to run lean but could still be compensated for by the other injectors without leading to a CEL?

I don't know. Hopefully, the injector analysis will shed some light. It does seem quite surprising to me that a largely stock engine would blow a piston. I know the additional 4psi of boost from the 15% pulley didn't help matters, but come on! Surely BMW built some safety margin into these engines. They had to expect that every gear-head on earth was going to plunk down a hundred bucks and bolt on a new pulley. It's irresistible!

 

I see.. honing sounds like it'll be ok.. good luck with the engine in the car.. I just realized u left the crank in the car and are "working around it" I hope the Rod bearings don't give u and trouble, and u have torque wrench access while laying under there..





yeah sounds like it went lean while u were ragging on it..

track abuse= raised AIT's from summer weather intercooler has to work harder, additional boost, Water and oil temps...

which would all make detonation that much easier and more prone..

I have a couple theories..

it could be a combination of them as well

it could be that the first injector was slowly getting gummed up.. and squirting less and less..

and unfortunately unless a person is running ITB's on their car... rarely do all cyl get equal air flow.. in this case Cyl #1 was probably getting more air (i.e. running leaner) then the others.. (this is just a theory as i haven't seen the R53 engine up close but it applies to many cars i've had experience with)

another possibility (although unlikely) is that when u run injectors near their maximum for long periods of time (near max generally means 90% + injector duty cycle) they can overheat.. and there is the potential for them to get "Stuck" either open or closed.. in ur case it might of became stuck closed

although I don't know the injector size of ur car.. I HIGHLY doubt 4psi over stock would max them out.. (how many HP are 1st gen injectors good for anyway?)

there's almost no chance this happend anyway

it's possible ur rough idle after the April event is related.. but tbh without a compression guage u never know... (I bought one a long while back... I call it the bearer of bad news :P)

it could just as easily been the spark plugs, the AFM, etc etc



ur 15% pulley is fine.. modern EFi is intellegent... it will compensate for the additional air by adding more fuel.. as the S/C pulls more air, it has to pass thru the MAF/AFM which in turn tells the injectors to "stay open longer" i.e. injector pulse or Injector Duty Cycle all the way upto the point of Boost cut (engine defense mechanism) or maxing out ur injectors (IDC is 100%)

as for ur question about injectors compensating for each other, they cannot..

because

a) each injector is independant of the next.. and can only "fire" into 1 cyl.. 4 cyl 4 injectors..

b) the engine doesn't monitor the A/F ratio of each cyl speratly.. only the "combined" total of the 4.. coming in and going out.. the engine simply assumes that all 4 cyl's get the same Air and Fuel in..

unfortunately variables such as injector health or Air flow design aren't monitored "live"

at MOST some of the hardcore guys have an EGT bunged into each header of the car.. temp fluctuates as well depening how "lean" the burn is..

but at this level it is not necc.. and without a standalone EMS u can't control injectors independantly anyway..


honestly it sounds like bad luck.. a low mileage injector to go out like that..

I know how u feel, I've lost 3 engines to detonation problems... (we have 91 **** water where I live)

Good luck with the build

I'm all for this project.. and this was actually one of my secret gripes with the forum, is the lack of Technical threads and build ups from DIY ppl.. especially coming from a forum full of shade tree mechanics where almost everyone does their own wrench work..

it's a refreshing change... plz don't let the thread die!

 

Ditto +1 to that statement "own wrench work..".

 

I have an update with photos on my blog at http://r53mini.blogspot.com.

Here's the latest if you don't want to browse there:

• I honed the block with the Flex-hone and the cylinders look great! The process did NOT make a mess of the bottom end of the motor. I think I'm safe there.
• I removed the front cover from the engine for easy access to reinstall the timing chain.
• I removed the rocker / lifters and cam from the head. I am ready to take it to a machine shop to have the combustion chamber deburred.
• I decided to send the fuel injectors off for service. I have some concern that the #1 injector may have been partially clogged, leading to a lean condition . . . and piston failure.
• I have ordered a new set of CP 77mm pistons with rings and wrist pins.
• I have ordered a set of ARP connecting rod bolts.

With any luck, I will have the pistons, rob bolts and cylinder head ready for installation during the July 4th weekend. The injectors will probably return the following week.

 

looks good man..

as for ur bump stick concern.. have u considered a re-grind of ur current one?

just make sure u clean the CRAP out of that crank and stuff before re-assembling! compressed air would be great..

take lotsa pics during re-assembly

could u also do me a favor?

if u have a kitchen scale.. could u weigh ur pistons? (stock vs CP) and the rods as well

i'm interested to see if u've reduced ur rotational mass.. (i.e. freer revving motor)

 

^+1

I'm doing this project for the second time now. I'm courious what your pistons look like, weigh, etc... Don't forget to weigh the pistons and wrist pins seperately. I foung that the wisecos were lighter, but the pins were so heavy it didn't matter.

I too am doing it in the car. This is much easier than people think. I recommend only taking advice from those that have actually done the work, ON a mini.

Good luck to you.

Oh yeah, I went with the JE's from Hubie. They look amazing and have all the features I wanted. Hubie has been very helpful and provided me with all the info I wanted and then some.

 

The pistons are scheduled to arrive tomorrow. I will definitely weight it all and post my findings.

My injectors will return from their service on Friday. I am quite eager to see the "pre-service" numbers.

I took the cylinder head to a machine shop yesterday to have them take a look at the pitting in the combustion chamber. In the machinist's opinion, I have nothing to worry about. He suggested I put it back as-is. I was concerned about any raised spots heating up and causing detonation. He said that only happens with iron heads - that aluminum would burn off. Made sense to me.

The only other item I am waiting on is some ARP rod bolts. They should be here in time for the weekend too!

 

how do the intake and exhaust gaskets match up to the head and respecting manifolds?

while ur waiting for parts to arrive.. u can do some porting and smoothing..

put the gasket on the head.. and use some machinists dye.. to stain it..
and see the excess material..

doesn't cost anything.. and it'll smooth the flow a bit..

 

Thank you all for your comments. I reassembled my engine with new CP pistons, ARP rod bolts, 180-degree thermostat, and the original rod bearings last Sunday. It came together perfectly, and it is running without issues so far.

For those interested, piston #1 is the one that broke. According to the injector analysis, #1 and #2 were a bit leaner than #3 and #4. The report is posted on my blog at: http://r53mini.blogspot.com/2009/07/...on-step-5.html

The full story of my repair is also available on the blog: http://r53mini.blogspot.com

The repair definitely took a lot of hours, but I have to say it really wasn't all that painful. These cars are really a joy to work on. They are cleverly constructed.

 

Hi guys. I’m new and just registered but it still won’t let me into the blog at the link.

Thanks for any help

 

Interested in blog as well. Can you check your DMs for my email and grant access? Thanks!