smoker

Beany-s12 · #1 16-11-2006, 19:33

i bought my s12 with a knocking bottom end and was smoking! changed the bottom end and she still smoked but lived with it! thinkin it must be turbo i got a t25 and fitted it but its smoking but is now getting worse especially after i've given it a thrashng! its got a new head gasket from when i did bittom end and the bloke i got the car from said the head had been fully rebuilt with new seals but he reckons he ported the head himself to the size of the gasket!
does anyone know if there is an oil feed in the head near the ports that he might of got too close to or if there might be anything else i should look at before rebuilding my spare head and swapping them over?

northerner · #2 16-11-2006, 21:23

is the smoke from cold start? on/off boost or idle? If its from cold and smokes after giving welly then chances are the stem seals are shot but they are easy to do with the head on!. Is there any play in the Turbo?

smoker · #3 16-11-2006, 21:38

Was the replacement turbo new or reconditioned ?. I had my turbo rebuilt by a specialist and when I got it fitted the engine was still smoking. Caused me no end of hassle as I then figured it must be the rings and got the block bored etc.
To eliminate the turbo I plugged the oil feed and let it idle for a few seconds and the exhaust was clear...

Might be worthwhile doing a compression check although i doubt this will show up anything if the oil control rings are worn.
I guess some wiser people will be along in a minute

smoker · #4 16-11-2006, 21:47

....If think he probably just matched the valve throat to the size of the gasket....usually chamfer the edge of the port wall slightly and remove any casting flash unless he decided to seriously open up the ports. I think you would see steam in the exhaust if he had gone to far with this to be honest.

s13eater · #5 16-11-2006, 21:56

you would not believe how much material you can take out of the et head, i had AMT engines do me one on the flow bench, if anyone read the write up on the cover supra, in the engine spec, you can see andy @ amt developed the head for it on the flow bench, its around 1000bhp, and if anyone went to the jap show at the pod, there was a light blue skyline r32 on the whiff bitz stand, this has also had the head ported @ AMT, andy also made the huge plenum for it.

Beany-s12 · #6 17-11-2006, 00:40

it only smokes on idle and gets worse the hotter it gets! i know the car the turbo came off and it wasn't a smoker but it did loose oil pressure and throw an end so could've killed the turbo aswell!
i'm gonna take the turbo off this weekend and got a mate whose gonna re build it for me!
might just go on a mad 1 and rebuild the old engine at the same time! the previous owner had only just rebuilt the old engine so its got all new rings, shells and oil pump but he didn't bother getting the crank measured so it wasn't long before a big end went!
am i better off using the s12 or s13 bottom end because i have both in need of rebuilds or are they both pretty much the same?

smoker · #7 18-11-2006, 19:24

smoking on hot idle sounds like how mine was when the old turbo was on it's way out. I would still plug the turbo oil feed on the engine block @ idle to verify where the smokes coming from before condeming the engine as they are very tough - i couldnt find any wear on my rings after 125k and 7 previous owners and there was just a few thou wear on the bores.