WHITE smoke under boost

[MXDesa]

Hey Everyone, this question is about a 1990 Eagle Talon AWD - But i think some of you can help because a lot of us boost.

I just got my Talon on the road from a 2 year slow build and i am only having one issue with it. The car smokes under boost. I had it at 10 pounds of boost and it wasn't so bad, but i up'ed it to 25 pounds of boost and it smokes quite badly. If i am light on the throttle it will not smoke and it does not smoke at all out of boost. The car has....

1- New everything on the bottom end
2- Brand new Precision SCM61
3- New Everything on the head (Valve guides, seals, etc...)
4- Metal Cometic Head Gasket.

Basically everything is new...

Now i have read, but cant remember where, that a lot of people have issues with pushing coolant into the chambers with high boost, when using a metal head gasket. Some had the problem fixed when they torqued the head to 100+ Ft. Pounds. ( I believe it was 115?? Can someone confirm?)

Any way can someone offer me some help and/or remedies they have seen work?? Thank you so much guys, otherwise the car runs great.

CLIFF NOTES:

1) Car smokes under boost only
2) New everything - Engine, turbo, seals, etc....
3) Can anyone help with some fix ideas??

Thank you Everyone!!

 

[get_nick]

why did you rebuild the head? was it for performance or because the headgasket blew once before. if it blew before you might have a warped head. i have a cometic head gasket on my sr and it's at stock tq. i would try a dsm forum if i was you.

 

[MXDesa]

I posted on a DSM forum and here. We have quite a few boosted members, maybe some have experienced similar problems.

The head was rebuild for performance reasons. 1mm Oversized valves, Bronze Guides, Springs, etc etc...

The Block was Over bored for lower compression pistons also. So it was not replaced because of blown gasket reasons.

 

[get_nick]

well, my experience with cometic suggests stock torque for the head bolts. i'm at a loss.

 

[b20b.eg]

whats the condition of the rest of the engine,your rings could be shiting,and is the turbo water cooled it cold have a slight leak

 

[turbo sol]

sounds like a coolant leak, possibly a cracked block leaking coolant into the combustion chamber. or could be from the head gasket. i know on hondas there are two of the rivets that need to be drilled out or it will cause a space between the head and block. if you didn't drill out the rivets that is where the problem might be. but only drill out the rivets that are between the head and the block. the ones that stick out are ok. or coolant might be leaking out of the water jacket(s) into the combustion chamber. or cracked cylinder wall. or cracked head. or it could be that all the air is causing the coolant to be sucked into the combustion chamber by one of the things i mentioned earlier.
do a cooling system pressure check. that should tell you if you have any leaks in the cooling system. hope this helps.

 

[civicious]

It's kind of far fetched, but one possibility is that the OLD motor had a bad headgasket and leaked coolant into the cylinders...

A catalytic converter can store water for quite a while, beleive it or not...you said it has a brand new motor in it, so it's highly possible that it had some problems with the old motor. It's highly possible coolant was making it to the exhaust, and is camping out in the catalytic converter. IF there is a cat on the car, that is...

like I said, it's somewhat far-fetched, but it's VERY possible...


Another option is that you (or whoever it is) didn't clean the deck/head surface completely, put the HG on upside down, mistorqued the HG, or has a cracked sleeve.

Another possibility is that if the turbo is watercooled, it's leaking there, and thus coolant is making its way into the exhaust.


One way or another, you're getting coolant in your exhaust.

 

[MXDesa]

Well i think you might be the closest to identifying the problem. Its not a daily car and it was a fully built engine and chassis. Im using a Precision SC61 so it isn't water cooled. Cometic head gaskets from what i hear have a issue sealing to the block properly if the deck surface isnt completely smooth so thats what im leaning towards. I think im going to end up getting a composite head gasket instead of using a metal/copper one.

 

[TurboMirage]

good idea.


also guys, 4g63's dont have water jackets like honda motors do. closed deck.

 

[turbo sol]

oops...my bad..