Recently, I noticed 2-3 mpg decrease (not a right foot problem) and misfire code at Idle for cylinder 3.
NO indication of excessive oil consumption, oil in coolant or coolant in Oil.

What I've tried:
1. Hoping its just a clogged injector I dropped in 15oz of Red Line SI-1 Fuel system cleaner into a tank of gas and that smoothed out the idle a good bit but no change in mpg and it no longer sets a misfire code, engine cold or fully warmed up. Still haven't burned through the whole tank of gas yet, Run maybe 100 miles.
2. Compression test:
1 2 3 4
Dry 155 160 100 165
Wet 171 176 110 185

3. Leak test - Don't have a leak down tester so I pressurized cylinder 3 to 100 psi and listened - I can clearly hear air coming from cylinder 2 spark plug hole, and at the tail pipe. When I pressurized the other cylinders I did not hear noticeable leaks and noticed my shop air leaks down much slower.

Current miles are 145K. I run 17% underdrive pulley with 380cc injectors & stock tune, CAI and cat back exhaust. Until recently was running NGK BKR6EGP plugs. Just swapped out for BKR7EQUP's. Suspension refreshed except for stock height springs Motor mounts replaced 20k ago with OEM. Engine belt replaced 20K ago, and no issues with tensioner or damper.

The Dry compression test and Leak Test tell me Cylinder 3 leaks at exhaust valve(s) and probably through the head gasket into cylinder 2, although I cant figure how it would do this and Cylinder 2 have so much better compression. The wet compression test tells me I have some piston ring wear but its pretty even across the cylinders (10-12% delta from dry).

Question #1 - I have run it pretty hard (WOT, 4/5th gear) down my private test track/country road and no hiccups. Thinking of pulling the head and having it rebuilt but given that it is rocking on pretty normally right now I'm on the fence.... So what would you do?

Question #2 - And has anyone here used Odessa Cylinder Head / Clearwater Cylinder head?
Think they are the same company out of Clearwater, Fl. For $575 shipped they will ship me a rebuilt head. No upfront core charge and prepaid return of my old. They don't care if the core is cracked or valves bent, as long as they get everything. For that price and the one stop shopping it sounds pretty good. I've got a local machine shop nearby I used on a BMW E30 rebuild and they do good work but price wise that's maybe $150 more than the E30 head rebuild cost me. I'm presuming in addition to pressure test, cleaning, decking and valve/valve seat hone/cut, the mini will require all new valve guides, new valve seals, maybe a couple of exhaust valves, and maybe a rocker arm or two.

Edit: Forgot to mention this is my DD. Bought it with 118k miles and I plan to run it for at least another 3-4 years. So yeah, I luv it and plan on keeping it. Part out not in the future to all the Colin Greene's out there.

Thanks, Bruce

 

 

Had to pull it, as it ain't gonna get better with time/miles and I'm off to the Twisties (HelenBlitz) in a couple months.


so off to the machine shop it goes tomorrow

 

 

With 145k you will for sure need some exh valve guides so make sure they do those and valve stem seals plus anything else they find.

Also with that mileage the timing chain is stretched so I would go ahead and replace it and the sprockets.
https://www.waymotorworks.com/timing...0-r52-r53.html

Also check the lobes on the cam for wear as we see them chewed up on high mileage cars. If you need upgrade to one of our mild cams and replace the rockers for the worn lobe.
https://www.waymotorworks.com/way-mi...t-r52-r53.html

 

valves look ok, machine shop will know when they look at it. Head looks to have been rebuilt b4 so my moneys on bad install. Check out the markings next to casting number

cylinders were pretty clean so maybe blown HG.

 

Thanks Way, so is there a cam that doesn't require spark plug tube adj, works with stock tune, JCW injectors, 17% pulley, cat back exhaust and CAI?

 

I'm in the middle of a n14 rebuild. The head was so choked up with carbon that the exhaust valves were leaking in a couple cylinders. I thought it may had been bent valves. I got lucky since a buddy owns a rebuild shop and touched up the head and valves and installed my seals, after cleaning and checking it, for 150. Good luck with your project.

 

I'm curious to know if you have any photos of the head showing the valves? I had to do a cylinder head swap and the valves that were burned on mine were discolored compared to the other valves. I'm curious if yours are showing the same effects.

 

Yes that is why we did our mild cam. Don't have to do anything to the spark plug tubes and works great with the stock tune and JCW injectors. You can run with the stock injectors, but it makes more low end with the JCW injectors.

 

David Baker - This is all I got. You can see exhaust valves in this pic. To me they look normal. As far as I know, Burnt, means burnt through. At that point, yes they should be discolored as they were subjected to higher heat than normal. Just my 2C.

 

You are braver than me, I would run, not walk from an N14. Between HPFP, Intake carbon buildup, Excessive oil consumption, Timing chain tensioner issues, PCV valve/valve cover sticking open, Turbo oil feed failures, and Turbo diverter valve failures, ect…… its just a world of pain to the wallet and adventures on the side of the road.
Sounds like he cut you a deal, walnut blasting the intake is reasonably priced at $350 and up. Guess he pulled the head and cleaned both sides along with valve seals?
Motor on!

 

Cool! That's what I'm looking for. Do you have a build sheet on the cam, i.e. lift, duration, etc?

 

Thanks for the photo. Looks like your burned valves are the discolored ones in cylinders 3 and 4. I bet if you remove those valves, there will be pitting and scoring on the valve seat. Not a terrible job, if I had the money at the time I did mine, I probably would've entertained a cam swap as well.

 

I've been working on cars and things forever, not much intimidates me when it comes to mechanical things. All issues with the n14 are correctable and preventable. The fuel pump is still under warranty for two more years. I'm doing all the work, just had a machine shop check valves and touch them up and put on the seals. Plus I paid 1500 for the whole thing LOL.