Low compression and high leakage on cylinder 6

[wan2play]

Hey, I just bought a Cobra. I'm just looking for some advice from some people who have bad the same problem.

Issues before I did the leak and comp test were....

-white smoke coming out exhaust. Thought it was excess fuel from BAP install w/o re-tune(was told it was by previous owner, he lied)
-Some misfires, no Cels
-no oil around valve covers or breathers in the beginning (he did a good job of cleaning it up)
-After I drove the car 80 miles to TIM Barth at Modular Power House, there was oil leaking out around the valve covers, breathers, and was told there was some burning out the exhaust. (you could see residue on the bottom of exhaust tip)


Cylinder 6 showed 120 psi and over 20 percent leakage.

I am at a cross roads. It could be as simple as a cylinder rebuild or as serious as a crack in the block. (I have an aluminator) Rod bearings ****ed...ect

Its about 9 hours of labor to tear down to block and see what is wrong($1000)

I find out its a the block that around 3.5k for a new short block and about 6 hours to assemble the long block plus another 9 hours.

^is it worth tearing the block down in hopes the motor needs a simple cyclinder rebuild, or should I just get a short block. I figure they would still have to reassemble the long block.

I'm just looking for some input so I can keep my sanity.

 

[DSG2003Mach1]

I think id find a borescope somewhere and see what you can see first...can check out the cylinder walls, look for broken piston etc

 

[SVT F15O]

Did you buy the car off this forum>??? If so warn others about this shady ****.

 

[wan2play]

Did you buy the car off this forum>??? If so warn others about this shady ****.

Yes, I bought it from him

http://www.svtperformance.com/forums/terminators-buy-sell-254/938595-fs-03-tr-vert-37k.html

 

[Fenixfire]

Damn, sry to hear bro. I helped a buddy buy a cobra about a year ago that had a KB 2.8 on it making 700 whp. Car was sick and a nice build. Even had a proline motor in it. After getting the car we find out its smoking and drinking coolant. Had to tear down the motor only to find the block had been resleeved and whoever did it did a crappy job because it dropped one of the sleeves and was sucking coolant.

I felt really bad because I helped him find the car. Really sucks how shady ppl can be. I dont think ill ever buy or help someone buy another car with a cracked open motor.

 

[Jomo1994z71]

Knew that car was priced too cheap...best of luck OP

 

[wan2play]

bump

 

[hotcobra03]

I had 2 different heads have cyl 6 only issues..both of mine were dropped valve seats.result in 0 compression.

had head repair only. labor to r/r head I did..cost stayed under a grand..

I also did full loaded head this last time cyl 7 crack. cost was 1500 r/r I did

my num6 piston has 2 large hash. marks from valve..mine is still rolling

 

[Juiced46]

Well you did a leakdown test and said there is 20% leakage from cylinder 6..... Where is the leakage coming from? That is your answer right there. Can you hear it out the exhaust, intake/throttle body or valve cover/oil cap hole? That will tell you where your issue is. If you have oil coming out the exhaust I am guessing blow by past the rings. Could be a cracked block, however if that was the case you should see oil in your coolant very easily.

Also a quick way to test if the cylinder wall is cracked- when you pressurize the cylinder for the leakdown open the coolant cap and see if its bubbling. If it does, its cracked

 

[Wicked46]

Where are you located?

 

[wan2play]

Well you did a leakdown test and said there is 20% leakage from cylinder 6..... Where is the leakage coming from? That is your answer right there. Can you hear it out the exhaust, intake/throttle body or valve cover/oil cap hole? That will tell you where your issue is. If you have oil coming out the exhaust I am guessing blow by past the rings. Could be a cracked block, however if that was the case you should see oil in your coolant very easily.

Also a quick way to test if the cylinder wall is cracked- when you pressurize the cylinder for the leakdown open the coolant cap and see if its bubbling. If it does, its cracked

crank case, but no oil in coolant. IM giving them the go ahead today to tear down to block