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-   -   Turbo SVT with possible blow by? (http://www.focusfanatics.com/forum/showthread.php?t=294310)

drostedrummer89 08-02-2012 11:55 AM

Turbo SVT with possible blow by?
 
I have been helping my friend Trevor (FocusOnTheD) with his ongoing issues in his fully built turbo svt. it doesn't build boost from a roll until nearly 4,000 rpm, and oil is spraying out of the dipstick tube due to the crankcase being pressurized, and we can't figure out why. We have done compression tests, leakdown tests, and none can completely point to a definate cause. He is going to send it to a professional speed shop if we can't figure it out.

The car was tuned on 13 psi and 18 psi, he doesn't even bother running high boost anymore, for fear that something's going to blow.

leakdown test:
cyl 1: 7% loss through valvecover hole
cyl 2: 10% loss through valvecover hole
cyl 3: 20+% loss through intake tube, also felt lots of air exiting thru cyl 4 spark plug hole when we pressurized cyl 3.
cyl 4:10% loss through valve coverhole

anything under 10% is considered within spec, right? The numbers did not change when we added oil to each cylinder and retested. is there any way a bad headgasket could be causing air to escape into an oil pressure or return hole? we checked cam bucket clearance on cylinder 3 to see if incorrect buckets were holding valves open, they were all at .006". could this mean bent valves?


Mods:
forged low compression pistons, forged rods
arp head studs
arp mains, billet caps
turbonetics t3 super 60 (freshly rebuilt by Turbonetics)
Tuned by tom

any advice is appreciated!
Matt

1turbofocus 08-02-2012 01:48 PM

What about the pcv ?

Tom

ZXthrizzle05 08-02-2012 03:10 PM

I used to have an issue with boost being built up. Turns out I didn't install the wastegate valve seal. So I put it in and it builds great. Also with my pcv it vents to the atmosphere. Wether or not any oil is spewing out of my dipstick I don't know but tiny bit does come out of the pcv sometimes.

drostedrummer89 08-02-2012 05:36 PM

wastegate is functioning, it has been repaired and is opening and closing at desired pressure.

tom, this is the car you have been helping us datalog. you helped us with pcv, it has a catchcan which is also spraying oil. pcv mod has been done.

there are only 20k on built motor. didn't know a fully built focus engine had such a short shelf life. we're wondering if rings weren't installed properly.

Matt

1turbofocus 08-02-2012 05:48 PM

So the valve cover is 1/2 inch hose and open , pcv is at lease 3/8 and also open and not going to the intake manifold ?

20% is high , did adding oil help any to lower the # ?

Tom

drostedrummer89 08-02-2012 07:34 PM

Right. No the oil did not help significantly. It did help it smoke significantly after startup, figures.

How in the world could pressure testing cyl 3 result in cyl 4 blowing out air? Cracked block? Cracked head? Blown head gasket?

Matt
Posted via FF Mobile

Indy'sexclusiveZx3 08-03-2012 12:32 AM

I vote cracked block

Roushturboedzx3 08-03-2012 03:26 AM

Crack block seems extreme to me. Prob broken ring lands or leaking valves.

1turbofocus 08-03-2012 08:40 AM

Quote:

Originally Posted by drostedrummer89 (Post 4289600)
Right. No the oil did not help significantly. It did help it smoke significantly after startup, figures.

How in the world could pressure testing cyl 3 result in cyl 4 blowing out air? Cracked block? Cracked head? Blown head gasket?

Matt
Posted via FF Mobile

My guess would be an open intake valve blowing it into the intake and into cyl 4 , if you have a cracked anything or blown HG you would have 2 dead Cyl and you dont

When you did this test did you have the valve cover off and check to make sure all valves closed on the testing Cyl

Tom

drostedrummer89 08-03-2012 09:30 AM

Quote:

Originally Posted by Roushturboedzx3 (Post 4290143)
Prob broken ring lands or leaking valves.

Don't leaking valves only cause air to escape through the intake? There's no way it could pressurize the block, right?

valve cover was off. i have read that sometimes a cracked or warped cylinder head or blown gasket can cause air to exit an ajacent cylinder. I need to redo the test and tap the buckets on cyl 3 to see if the valves snap shut. may also pull the cams.

We are really hoping its in the top end, we don't want to get into a full rebuild.

as a side note, we did the same leakdown test under the same circumstances a few months prior, and we had ALOT of air leaking from valvecover. like over 20% on 2 different cylinders. we were surprised that we didn't get anywhere near the same results. we'll do it a third time and check back.

Matt


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