My friend has a 420at atx pushing 10lbs of boost, but he was having problems with the fuel at wot. The fuel would reach the right level and then the pressure would fall back down to a lean condition. Injectors were good, begi fuel pressure regulator was sent off to be fixed, got it back hooked it up and still had the problem. The last thing to check was the fuel pump. So since I have a walbro 255 hp(about to go turbo) and so did he we switched assemblies. He takes off down the road and problem seems to be fixed but wait, he leaves my house turns on the road and "checks" it again and...oh s%*t! Huge plum of white smoke is behind him, car is still running though. What could the best case scenario and worst case scenario be. I was thinking head gasket for best and pistons and valves for worst. What do you guys and gals think?

Originally posted by Slo2g
My friend has a 420at atx pushing 10lbs of boost, but he was having problems with the fuel at wot. The fuel would reach the right level and then the pressure would fall back down to a lean condition. Injectors were good, begi fuel pressure regulator was sent off to be fixed, got it back hooked it up and still had the problem. The last thing to check was the fuel pump. So since I have a walbro 255 hp(about to go turbo) and so did he we switched assemblies. He takes off down the road and problem seems to be fixed but wait, he leaves my house turns on the road and "checks" it again and...oh s%*t! Huge plum of white smoke is behind him, car is still running though. What could the best case scenario and worst case scenario be. I was thinking head gasket for best and pistons and valves for worst. What do you guys and gals think?

HG

Originally posted by eclipse982nrRST

Originally posted by Slo2g My friend has a 420at atx pushing 10lbs of boost, but he was having problems with the fuel at wot. The fuel would reach the right level and then the pressure would fall back down to a lean condition. Injectors were good, begi fuel pressure regulator was sent off to be fixed, got it back hooked it up and still had the problem. The last thing to check was the fuel pump. So since I have a walbro 255 hp(about to go turbo) and so did he we switched assemblies. He takes off down the road and problem seems to be fixed but wait, he leaves my house turns on the road and "checks" it again and...oh s%*t! Huge plum of white smoke is behind him, car is still running though. What could the best case scenario and worst case scenario be. I was thinking head gasket for best and pistons and valves for worst. What do you guys and gals think?

HG

Def. HG.

Compression test.

He took the car to a shop to get a compression, leak down, and computer test run. Shop wouldn't do all of them like the store clerk said and now he can't get the car to start back up. I think he said that it started one time, he put it in reverse and then it died on him and wont start again. Is this all due to a head gasket? I knew his hg was blown but what about this new situation?

oh yes no compression= no start. good luck wit hte hg its not too hard on our cars!

If you have a dead cylinder it could still start..

Rent or go buy a compression tester.. cheaper then paying the shop. Why start it, drive it to the shop and destroy other parts???

Hey just to keep everyone informed he did a compression test today and the results were from left to right 150, 60, 60,60. He is going to do a leak down test asap. What does everyone think, still just a hg?

yea its prolly just a headgasket. unless sumhow his rings gor seriously fucked

Ok he is starting to pull apart the car today, he did a leakdown test and could not hear any blow by. He did mention to me that he heard some ticking when the car was running...maybe a valve? What do you guys think?

ok, i'm the guy that is having the problems... heres the scoop...

this is what happened. I hit full boost reving up to around 6000. sounded like extra loud air coming out of my external wastegate like ive never heard. I backed off, and saw lots of white smoke behind me.

Rough idle.
ate oil fast as hell.
muffler drenched in oil.
REAR BUMBER with thick oil film too!
white smoke billowing up from rear of engine closest to the firewall.
Oil pouring onto downpipe near rear of engine too.

Compression came originally before the tear down to be 150-60-60-60. I tried a leak down, and had no air leaking from any crevise at all. wierd... So i was pretty convinced that its probably just a head gasket.

finally, today, i got the head off and am checking out the gasket to see any defects. It was an MLS and i can not see any flaws in it. I was hoping to see the HG in pieces according to the problem i was having.

main question would be, would it be a bad idea, or waiste of time/money to check out the ring lands while its apart? or should I just reassemble with the new HG set after valve job and see what happens?

Could it possibly be a ringland, or piston ring problem? I was convinced after the leakdown cuz of no blowby that the rings were fine...

gimme input...

i would definetly say just a headgasket. but if you put it back togather check the dowells on the block because i did my head and when i put the head back on one of them was fucked up and i had no compression. and also just cause you dont see anything wrong with the headgasket doesnt meand its not warped or something. good luck!

are you running 10psi on stock BE? If so for how long?

been runnin it for about 6 months or so. Hahn says it'll be ok up to around 14lbs boost (pushin it). as long as the fuel's there... its a gamble though in my opinion.

Im replacing the rod bearings and piston rings while i got em out. Just to be safe. Might as well since they're out.

my other 420a spare motor will see 28 or so lbs boost once its done.

this is off the subject, but anything i can do to beef up my auto tranny to withstand higher horsepower levels?

I'm willing to bet you cracked the piston ring lands..Its hard to blow an MLS headgasket like that. 10 psi on a stock motor is pushing it, any light amounts of detonation, it will crack the piston ring lands. Take out the pistons, and you can check the ring lands for hairline cracks between the ring lands. Usually, when you take off the rings, the pieces of ring land will just fall off the piston. Sometimes you cant tell unless you take the rings off as well.

Originally posted by XtremeRS
I'm willing to bet you cracked the piston ring lands..Its hard to blow an MLS headgasket like that. 10 psi on a stock motor is pushing it, any light amounts of detonation, it will crack the piston ring lands. Take out the pistons, and you can check the ring lands for hairline cracks between the ring lands. Usually, when you take off the rings, the pieces of ring land will just fall off the piston. Sometimes you cant tell unless you take the rings off as well.

well, we'll see.. I hope not, but if so, no big deal, ill just replace. its most likely that a head gasket will go before I break any metal.

well i retract my previous statement about the head gasket. i diddnt know it was a mls, and i diddnt know u were pushin 10lbs of boost id say its the ringlands then. my bad.

Originally posted by XtremeRS
I'm willing to bet you cracked the piston ring lands..Its hard to blow an MLS headgasket like that. 10 psi on a stock motor is pushing it, any light amounts of detonation, it will crack the piston ring lands. Take out the pistons, and you can check the ring lands for hairline cracks between the ring lands. Usually, when you take off the rings, the pieces of ring land will just fall off the piston. Sometimes you cant tell unless you take the rings off as well.

I'm with XtremeRS on this one. Twice this has happened to me, and it was the ring lands, just as described.

See.. I doubt your head is warped because you orginally had compression, and it happened all at once... and I seriously doubt you "blew" the MLS HG. Ringlands IMO.

P.S.. Mobil 1 oil (and probably all other full synthetics) burns white, so I tell it apart from coolant by the smell.

Originally posted by 420agreenvilleSC
Hahn says it'll be ok up to around 14lbs boost (pushin it). as long as the fuel's there.

I would hope Hahn would not say that!

I am sorry to hear it was worst case scenario bro. Everyone was screaming HG and when I reread your post and you said 10psi...red flags went up in my head. I mean its posted on here everyday that most don't go over 8psi.

But now, we have a guy that just joined pushing 16psi on stock BE and making 300+whp and in the mid 12's in the 1/4 with it.

But I hope you the best in your rebuild man. Let us know how everything works out!

Originally posted by rs_smoked_you
i would definetly say just a headgasket. but if you put it back togather check the dowells on the block because i did my head and when i put the head back on one of them was fucked up and i had no compression. and also just cause you dont see anything wrong with the headgasket doesnt meand its not warped or something. good luck!

when you say messed up dowells, you're talking about the metal tubes that stick up on the corners of the block or cylinder head where they meet when torquing down bolts?

yup! one of mine were messed up a bit and when i put the head back on it had no compression.

Originally posted by rs_smoked_you
yup! one of mine were messed up a bit and when i put the head back on it had no compression.

well, as a matter of fact, one of mine is broken in half. When i removed the cylinder head, half of it was in the head, other half in the block. I got the half that was in the block out, when i get the head back from the valve job, ill take that half out too.

Where did you get a replacement dowell from? cuz i need one

replacement dowels can be bought at the machine shop. I have a few from junkyards if you need one.

Terry

Originally posted by Star Turbo Talon
replacement dowels can be bought at the machine shop. I have a few from junkyards if you need one. Terry

that i do. what do i do now, give u my address over the phone?? lol

just to follow up on the events that have happened...

ALL piston's ring lands were broken
#4 cylinder and piston vertically scored to hell.

Now i get to spend more $ to fix the problem.
thanks guys for the help..