hungryhip-ccp

iTrader: (2)

LSJ turbo'd 40k on stock head with 78's. after sitting from a drive (so up to operating temp) and re-starting smoke's for 2 seconds

comp test cold, dry, cranking, 165 across the board

leakdown, warm 12-14% going by the rings

visual: can visually see oil residue on top of number 1 piston after shut down

plug is clean and free of deposits. all other cyl clean and great looking.



so, this tells me few things. since comp and leakdown tested fine then its a cyl head problem im assuming. it could be either valve guides or valve seals.

i had the head checked and decked about 8k mi ago when i did a head gasket, they said it checked out fine... (im questioning if they even checked it or not)

since there is no oil on the plug and the engine never smokes once its running im gonna have to say 100% its leaking down upon shut off.


my question is who has had this happen and at such low mi? i also have a oily residue on top of all my valves.

car runs and drives fine, my issue is i dont wanna cake/clog up that pistons rings and cyl with a bunch of junk and end up getting a stuck ring...

ls1fbody

even though they're all ~165 isn't that a bit low?

hungryhip-ccp

iTrader: (2)

nope not for forged pistons in a cold engine. i could of done a hot, wet test and got probably 200 across. but when its hot and wet im usually working on my girl, not the cobalt...!

what matters most is there all the same and above 100psi

100psi is the cut off according to alldata.com

ls1fbody

ah gotcha. Forgot about your pistons.

slowswap

Valve seals is my guess. They may have been fine when they were checked but since have worn?

hungryhip-ccp

iTrader: (2)

well and im sure ray set up the ring gaps for a pretty loose engine, he knows that i lay the boost to it!

i cant tell my self if it needs seals or guides, if i put in seals and it needs guides it will last about 1 or 2 oil changes before it starts again.

i wonder if the stiffer springs and increase boost over stock is causing the guides to wear prematurely

and if thats the case im looking for a upgraded hardened guide of some sort to help fix not repeat the problem, lol

twzted

I know some have had this issue or a similar one due to not venting the valve cover enough...

simple check would be to take off the oil cap, I don't know if you have vented it more or not but just an idea, might be completely unrelated even, but worth a shot

Area47

new total seal rings? a simple yes or no will suffice.

hungryhip-ccp

iTrader: (2)

yeah, i'v tried that. i have a vented oil cap breather thingy. but thats the same thing i tried/thought of first.



dont know what you mean by "New"? new style or asking if i re-used my old ones.

purchased in nov/dec of 2009 when the block went to Bates engineering. He did the short block. New rings, orig diamond pistons.

Area47

new, as in brand new. how many miles on it so far?

hungryhip-ccp

iTrader: (2)

um 6k ish

Area47

did you go out and beat the **** out of it with less than 1k miles on it? if not, you should have.

hungryhip-ccp

iTrader: (2)

this was my first leakdown and comp on his shortblock, i always try and do one and change plugs every 5k. i change oil @ 50mi 500mi and every 2500 after break in.

broke this one in on mobil 1, no boost for 500mi and not past 10psi till 1500mi per ray's instructions.

my first motor i boosted it from mile 1 and broke it in on conventional.





i have already done a leakdown and there is not a bottom end/rotating assy problem. i think its the head, key sign is there is no burnt oil on the plug and the plug is dry not wet. that means that its leaking into the cyl while its not running. if it was a stuck ring or bad ring gaps or glazed cyl it would smoke all the time and the spark plug would look exactly like the top of the piston. it doesent.

mexi_loco

iTrader: (7)

i'm no expert, do you think it could be due to excessive crankcase pressure? I kind of agree with the worn valve guides as well.

SlowBalt_06

iTrader: (-1)

Vavle seals my guess

Area47

i learned that total seals need to be hammered on. hard. i did 5 dyno pulls on mine with 800 miles on it before it would stop rolling blue smoke out of the exhaust. i used royal purple break in oil for 250 miles, then rp 5w30 for about 150. now on mobil 1 sitting about 1500 miles in.

going off the leak down numbers, you're an ass hair away from the service limit, but thats for stockers. rings are gapped at? this plays a lot into it. is it using oil? or just a light film on the pistons themselves?

hungryhip-ccp

iTrader: (2)

i did a breather on top of the valve cover and it didnt help, i was thinking and hoping it was that

i also did the leakdown cold, cause it cooled off by then. i didnt gap these rings, but i heard from others ray does em loose if he knows your boosting alot.

its not using any oil at all, and only cyl 1 has oil on top. when i look down the spark plug hole its wet and shiney in number 1 only, it looks like a 300,000 mile dodge 318 i just changed the plugs on lol

the rest of the cyl i can still see the aluminum

Area47

where did the air go on the leak down? past the rings? do a leak down with the motor warm and see where it goes.

hungryhip-ccp

iTrader: (2)

yeah right past the rings. all the sound was coming from oil cap.


if it was seals or guides a leakdown will not blow hard enough to reveal this right? i thought it wasnt enough pressure to overcome the seals?

im no leakdown expert, only done a handfull of em

Area47

it can go past the seats, but this will result in a really high leak down percentage. been there, done that. it's more likely to go past the seats and out of the ports. so you won't find out for sure. pull the intake manifold, and exhaust. look for any odd clean residue from oil on the guides. if they are clean, it's not the head. or just yank the head and have it pressure checked.

if that comes out fine. next step is the bottom end.

shitty elimination process.

in that one cyl when doing a compression test, put a bit of oil in the cylinder and see what the numbers do. if they go up. it's rings.

reddevil

iTrader: (1)

You cannot use a leakdown tester to test for worn valve guides..

breaking in an engine on synthetic oil sucks.. break in will take a long time and their is a chance rings will not break in on synthetic oil. what was used on the cylinder during assembly is very important to ring break in, you do not want to use synthetic oil.

to check for a warn guide you need to move valve side to side and check free play.

hungryhip-ccp

iTrader: (2)

i used to break in all my motors on conventional but Ray from Ray Bates Engineering built this engine and he told me he has switched from breaking in on conventional to using a synthetic (usually Mobil 1 20-50w). he said there was no noticeable benefit at all from using conventional oil during the "break in period"

he said he would disassemble engines that had been broken in on both and the only thing noticeable he said was the Mobil 1 engine was always cleaner and less deposits than the engine broken in on conventional.

remember if we were to be talking about a chevy 350 with a new cam then yes break in oil would be crucial and would def be needed.

to my understanding thats the thing break in oil offers, is more zinc which they have tried to eliminate from all on the shelf brands.

think about it, what was in the engine from the factory? mobil 1 5w-30 synthetic! we all broke our motors in on it. unless someone can show that a different oil is in it for delivery of the vehicle.

but i think if that was the case then there would be alot more strict break in procedure and it would be explained to you before leaving the lot, as conventional oil would never make it one service interval on the cobalt oil life meter takes you anywhere from 7-15k mi before alerting you of a oil change. thats the way i look at it

BLAZIN07SS

iTrader: (7)

you can still find zinc in the european mobil stuff

hungryhip-ccp

iTrader: (2)

Im thinking im gonna plan some down time for

http://www.zzperformance.com/cobalt_...1015&catid=174

and

http://www.m2race.com/product_specs.asp?ID=5

and

http://www.zzperformance.com/cobalt_...1013&catid=174



im at 120% idc on 60's now, with the above mods would i need 80's? or will the brfps be enough?

Area47

Stop half assing the fuel system. Over build it