Compression Test results

[LeoGSVT]

for those of you who have been keeping up with my post, about the ticking noise i had comming from my heads, and then after last nights episode, when the car just died, and smoked the hole way home...we pulled the plugs and did a compression test today..the results killed me....we did just the drivers side head first, and all the plugs looked like they were just dipped in oil...it looks as if oil shot out from under the valve covers both ways, there was even some oil on the blower...if you swipe your finger inside the tail pipe, its just black oil, and the entire back bumper in glazzed in oil...compression came as followed...if the passeger side is 1-4 and drivers side in 5-8.....the #5 came back around 150, #6 came back around the same, but the #7 came back as 0!!!!!!!!!!!!!! we put the adapter from the compression tester into an air hookup and blew air through that #7 cylender, and we heard air come out through the intake..then i turned the motor over once or twice and we heard air come out of the exhaust..im pretty sure its a burned up piston, or a serious problem in the head...pics are to follow once we get the heads off...

 

[MY DREAM]

That sucks, did you get compression on the other cylinders? 7 & 8 ar known for going out first due to heat stress and the .001 piston to wall clearance. Keep us posted as to what the cause and effect are.

James

 

[Jimmysidecarr]

Sorry to hear that...

The combo of tight pistons(.001"piston to wall) and less than spectacular head cooling... unfortunately rears it's ugly head in the form of detonation super heated, and over expanded pistons...

Quite often they will grow right out into the wall... and nearly seize... sometimes when the piston gets yanked down in the bore, the top ring and ring land will get pulled right off the piston :uh oh:

This is why beyond a certain power threshold(unknown and variable)... cooling mods are recommended by me and others...

If we had even .002" piston to wall we wouldn't see half of these piston failures...

I hope the bores are not too bad and that the rebuild will be reasonably priced.

Good luck with it...

 

[postban]

Bummer man. Just goes to help hammer the fact home, 19psi is too much without conservative tune and racegas.

 

[sbc.cobra]

man that sucks...time for a stroker though :banana:

i'm sure i'll end up w/ one b/c i am running 19 lbs as well. i'm going w/ the complete Evans cooling setup and a conservative tune to help (hopefully) prolong the engine.

 

[CWD]

I'd condider VT engines

Before spending too much. I've already decided that is what I'll do in a similar situation. Just a suggestion. Wonder if LDC Mod would have prevented this from happening??? Humm.. Were you on NO2 @ 19psi when it went? Hope all works out for you.

 

[Yates...Man]

for those of you who have been keeping up with my post, about the ticking noise i had comming from my heads, and then after last nights episode, when the car just died, and smoked the hole way home...we pulled the plugs and did a compression test today..the results killed me....we did just the drivers side head first, and all the plugs looked like they were just dipped in oil...it looks as if oil shot out from under the valve covers both ways, there was even some oil on the blower...if you swipe your finger inside the tail pipe, its just black oil, and the entire back bumper in glazzed in oil...compression came as followed...if the passeger side is 1-4 and drivers side in 5-8.....the #5 came back around 150, #6 came back around the same, but the #7 came back as 0!!!!!!!!!!!!!! we put the adapter from the compression tester into an air hookup and blew air through that #7 cylender, and we heard air come out through the intake..then i turned the motor over once or twice and we heard air come out of the exhaust..im pretty sure its a burned up piston, or a serious problem in the head...pics are to follow once we get the heads off...

Hey, you might have some burnt valves pal, it may not be the piston. Your hearing air from the intake and exhaust, more than likely you cooked some valves.

Piston could be the culprit but possibly not. The valves in these motors aren't the best of the best for sure.

Pointless now but a good leakdown test could tell you where the pressure is going, and I bet it's not going past the rings instead it's going past the valve seats.

Two of these will set you straight for your upgrade.

M-6099-GT** 3k for a set of these bad boys.

GT heads feature a reduced size lash adjuster allowing for a raised intake port, creating a more direct intake path
These heads are the final revision of the 2000 Cobra R heads
The most durable highest flowing modular engine cylinders heads available
Bare head used on M-6007-R50 Grand Am cup race engine
Fully loaded assembly
37mm intake valves, 32mm exhaust valves
Intake valve lift: 11.2mm, exhaust valve lift: 11.5mm

 

[LeoGSVT]

i had several people tell me it may be the valves..because the car ran today, just fine, just smoked alot

 

[IronTerp]

Dang Leo! Really sorry to hear the latest news. You've had some "character building experiences" with thsi car.......

 

[Silverboost]

burnt valves still cost a lot of money to fix also...I would replace the heads with the newest revised heads and if you are going that far you might as well replace the pistons since the engine is going to be out anyways..good luck
Mike

 

[ShelbyGuy]

burnt or notched valves does not explain the smoke or the oil

 

[FireRed04Vert]

Hey, you might have some burnt valves pal, it may not be the piston. Your hearing air from the intake and exhaust, more than likely you cooked some valves.

Piston could be the culprit but possibly not. The valves in these motors aren't the best of the best for sure.

Pointless now but a good leakdown test could tell you where the pressure is going, and I bet it's not going past the rings instead it's going past the valve seats.

Two of these will set you straight for your upgrade.

M-6099-GT** 3k for a set of these bad boys.

GT heads feature a reduced size lash adjuster allowing for a raised intake port, creating a more direct intake path
These heads are the final revision of the 2000 Cobra R heads
The most durable highest flowing modular engine cylinders heads available
Bare head used on M-6007-R50 Grand Am cup race engine
Fully loaded assembly
37mm intake valves, 32mm exhaust valves
Intake valve lift: 11.2mm, exhaust valve lift: 11.5mm

I'm willing to bet the ranch it's a piston. It will blow air out the intake and exhaust simply because the valves are normally open during engine rotation. I have never, ever seen oil everywhere from burned valves. You could have gone one step further and tested the air flow ensuring the piston was on tdc of the compression stroke and checked for air flow. If it's coming out the intake or exhaust then, it could be valves. I'm betting it comes out the crankcase. But a piston failure could damage valves too...so it's possibe they are in fact damaged too. By the way...did you happen to look and see if you had broken a valve spring and dropped a valve? Just a thought...

Those GT heads...my understanding is they won't fit these engines. Am I wrong?

 

[CobraBob]

That is really a bummer. Best of luck on getting it resolved. I have no doubt the new motor will be a bit more stout.

I read these stories and get concerned for the many motors out there pushing 17+ lbs. boost with regular fuel. I'm of the opinion that if you're going to go for big boost (and max power) it is smart to address the internal issues. Pushes the investment up a notch but in the end it would probably be well worth it. Dang Ford for making it way too easy to make this much power! :-0

 

[WDW MKR]

I don't believe you can use the GT heads without a custom intake. I'd bet you have some head damage, along with piston/cylinder problems.

 

[Yates...Man]

I'm willing to bet the ranch it's a piston. It will blow air out the intake and exhaust simply because the valves are normally open during engine rotation. I have never, ever seen oil everywhere from burned valves. You could have gone one step further and tested the air flow ensuring the piston was on tdc of the compression stroke and checked for air flow. If it's coming out the intake or exhaust then, it could be valves. I'm betting it comes out the crankcase. But a piston failure could damage valves too...so it's possibe they are in fact damaged too. By the way...did you happen to look and see if you had broken a valve spring and dropped a valve? Just a thought...

Those GT heads...my understanding is they won't fit these engines. Am I wrong?

Good point, but if he has a valve guide that is completely destroyed couldn't some oil seep thru? Maybe a long range possibility for hope of less damage to his motor.

The GT heads will fit everything but the intake, nothing a Sullivan piece won't fix with a couple of tubos strapped to it.

 

[WDW MKR]

Yeah... if only a Sullivan and twins was cheap!

Any updates on the engine?

 

[ShelbyGuy]

failure analysis fascinates me. im interested in whats up too.

 

[Yates...Man]

Yeah... if only a Sullivan and twins was cheap!

Any updates on the engine?

True.

 

[LeoGSVT]

the car is still sitting as of now, i have arrangments to tow it up to my shop on tuesday and start breaking it down...pics are to come

 

[FireRed04Vert]

Good point, but if he has a valve guide that is completely destroyed couldn't some oil seep thru? Maybe a long range possibility for hope of less damage to his motor...snip...

Hmmm...you know, it could! And that could also have been his noise he originally heard. But I can't see that blowing the oil all over the engine compartment. But with all the boost he produces, it does raise some interesting alternatives. I would have liked to do the compression and air leak tests myself. I think we would have had a difinitive answer. I'm sticking with the piston theory for now...but you have me thinking....