compression test results

Gh0stRep0rt

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so i end up with an engine code of running lean on bank 1 and No.1 fuel injector malfunctioning and the wrench came out and shutdown my car.
i check the timing to see if it moved but its all good, i check the inside of the cylinders with a borescope camera and the walls show no sign of damage and piston only show small carbon build up. car doesn’t over heat at all so i don’t think is the head gasket. the heads were clean out and the valve seal were replace... at this moment i don’t know what else to look at, any help will be appreciated
p.s is a build stroker engine with cams.


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rickf

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Did this just happen on a good running motor or did it happen on a fresh build? It is looking like someone screwed up on the head milling or head gasket thickness. Way too consistent across all four but different side to side.
 

Gh0stRep0rt

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Did this just happen on a good running motor or did it happen on a fresh build? It is looking like someone screwed up on the head milling or head gasket thickness. Way too consistent across all four but different side to side.



good running motor, the block was build on dec of last year and didn’t start driving the car until may 23 of this year. i did took the heads some where else to get it clean and inspected, i installed the heads,cams and timing...


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Gh0stRep0rt

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Were the cams degreed when they were installed?

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well i have the comp cams mutha thumpr and honestly i dont know what you mean by degreed. i installed them


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rickf

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Now, Did you do a compression test before and know for a fact it was good when the motor was put together? This may have been this way for a long time and the code and other issues are unrelated to the compression.
 

Gh0stRep0rt

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Now, Did you do a compression test before and know for a fact it was good when the motor was put together? This may have been this way for a long time and the code and other issues are unrelated to the compression.



never did a compression test on the day of the installation and that was my mistake...
i put a little of oil into the cylinder to see if the psi jump higher, but it only moved 5 psi... i dont know how high it has to move to determine if the piston rings are the problem


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01yellerCobra

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well i have the comp cams mutha thumpr and honestly i dont know what you mean by degreed. i installed them


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When you degree cams you make sure the cams are installed correctly. Sometimes they're ground a little off. Your numbers look like a cam timing issue to me.

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swflastang05

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Compression testing alone is not reliable enough to diagnose anything, you really should do a leak down test next to get a better idea what's going on IMO.
 

Gh0stRep0rt

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When you degree cams you make sure the cams are installed correctly. Sometimes they're ground a little off. Your numbers look like a cam timing issue to me.

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ok ill search on that tonight and ill call comp cams for any info., thank you


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RED09GT

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Either the cam timing was off when installed or you have a broken tensioner or guide.
 

702GT

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If the cams were off even 1 tooth either direction it would kick a CEL and the car would run like dogshit. May even PTV if a tooth off retarded. Don't know what this cam degree talk is about, there's no degreeing VCT cams. Phasers only install one way, can't mess that up unless you're *really* special. Have seen improperly torqued cams sheer the dowel pin off the phasers before, but that would be catastrophic. Have seen people mess up the phaser spring doing limiters or lockouts, but again it would throw CEL's and VCT would not function properly.

If the cam grind is off, it's in the grind itself and would be comp cams bad. Can't see the car running great for a time, and then showing problems, if the grind was bad. Bad tensioner or guide is top most likely if it is a cam timing issue.

I agree with a leakdown test, but I'm not sure why 1 bank would present with issues over the other. The odds all 4 rings on 1 bank were incorrectly installed seems flakey in theory. Why are there issues now vs day 1? I think a bad guide/tensioner is more likely. Even if the heads/deck weren't milled correctly, it would be a constant, not a random down the road. If there were a problem with a head it would also be a constant, if not at least an isolated failure of a single cylinder. All 4 at the same time suggests timing.

Comp Cams isn't QC perfect either, I had a SN95 friend put cams in his GT, when we went to install we double checked part numbers to identify LH from RH, and found we had 2 RH cam shafts. Brand new in the box lol. Needless to say, he got some goodies from Comp as well as a LH cam.
 

Gh0stRep0rt

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If the cams were off even 1 tooth either direction it would kick a CEL and the car would run like dogshit. May even PTV if a tooth off retarded. Don't know what this cam degree talk is about, there's no degreeing VCT cams. Phasers only install one way, can't mess that up unless you're *really* special. Have seen improperly torqued cams sheer the dowel pin off the phasers before, but that would be catastrophic. Have seen people mess up the phaser spring doing limiters or lockouts, but again it would throw CEL's and VCT would not function properly.

If the cam grind is off, it's in the grind itself and would be comp cams bad. Can't see the car running great for a time, and then showing problems, if the grind was bad. Bad tensioner or guide is top most likely if it is a cam timing issue.

I agree with a leakdown test, but I'm not sure why 1 bank would present with issues over the other. The odds all 4 rings on 1 bank were incorrectly installed seems flakey in theory. Why are there issues now vs day 1? I think a bad guide/tensioner is more likely. Even if the heads/deck weren't milled correctly, it would be a constant, not a random down the road. If there were a problem with a head it would also be a constant, if not at least an isolated failure of a single cylinder. All 4 at the same time suggests timing.

Comp Cams isn't QC perfect either, I had a SN95 friend put cams in his GT, when we went to install we double checked part numbers to identify LH from RH, and found we had 2 RH cam shafts. Brand new in the box lol. Needless to say, he got some goodies from Comp as well as a LH cam.



thanks, on Monday i will be able take apart and inspect everything that have to do with the timing and hopefully it come to an end of the compression problem


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05gtowner

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If the cams were off even 1 tooth either direction it would kick a CEL and the car would run like dogshit. May even PTV if a tooth off retarded. Don't know what this cam degree talk is about, there's no degreeing VCT cams. Phasers only install one way, can't mess that up unless you're *really* special. Have seen improperly torqued cams sheer the dowel pin off the phasers before, but that would be catastrophic. Have seen people mess up the phaser spring doing limiters or lockouts, but again it would throw CEL's and VCT would not function properly.

If the cam grind is off, it's in the grind itself and would be comp cams bad. Can't see the car running great for a time, and then showing problems, if the grind was bad. Bad tensioner or guide is top most likely if it is a cam timing issue.

I agree with a leakdown test, but I'm not sure why 1 bank would present with issues over the other. The odds all 4 rings on 1 bank were incorrectly installed seems flakey in theory. Why are there issues now vs day 1? I think a bad guide/tensioner is more likely. Even if the heads/deck weren't milled correctly, it would be a constant, not a random down the road. If there were a problem with a head it would also be a constant, if not at least an isolated failure of a single cylinder. All 4 at the same time suggests timing.

Comp Cams isn't QC perfect either, I had a SN95 friend put cams in his GT, when we went to install we double checked part numbers to identify LH from RH, and found we had 2 RH cam shafts. Brand new in the box lol. Needless to say, he got some goodies from Comp as well as a LH cam.

THIS^^
 

Gh0stRep0rt

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well it seen you guys were right... thanks
2c4c333dc90ddcf5a03380777262e7f0.jpg



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Wes06

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Judging by the mating surface there. Someone enjoys using rtv.
 

Gh0stRep0rt

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Judging by the mating surface there. Someone enjoys using rtv.



yea [emoji23]. i decided to buy a canton louver windage tray, a couple of miles later i notice oil on the drive way and when i look underneath, the oil pan was all wet... i should have stay with the oem one[emoji20].


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