compression results are in

cbarr300 · Aug 6, 2007

150.......140
150.......30
145.......150
139.......150

Since I re-did my rockers I've had some bad valve train noise. Looking at these numbers, I'm imagine that my intake valve isn't really opening so air can't get in. (If I'm not mistaken, some compression can be made by the exhaust side so that may account for my 30 psi)

so I'm guessing it's one of two things.

either:

1. My pushrod's bent (unlikely)
2. My lifter collapsed (really likely)
3. I adjusted this rocker wayyy too loose (I did this the same as the others..but it happens.

the reason I think it's too loose and not too tight is because of the noise I'm getting from around the 7 cylinder

anyone else have any ideas or just wanna say, "Yeah, that's prolly it"

thanks

EDIT: no coolant in oil or oil in coolant.

cbarr300 · Aug 6, 2007

also, if my rockers were THAT loose....I think I'd be hearing more than just a knocking/tapping noise. I'd think I'd be dropping valves left and right.

Dino Dino Bambino · Aug 6, 2007

The only way you're gonna find out what's going on is to pull off the driver's side valve cover and investigate.
It certainly looks like your no.7 intake valve is hardly opening at all and the reasons are most likely to be either a loose rocker, bent pushrod, or collapsed lifter. Hopefully it'll be one of the first two so you won't have to pull the intake and head.

final5-0 · Aug 6, 2007

Ever consider what might happen if the ev is too tight

Grady

cbarr300 · Aug 6, 2007

Grady, I thought about that...but that wouldn't explain the noise from around that area. If it was too tight, I'd imagine it'd be pretty quiet.

maybe....the exhaust valve is too tight and the intake has a collapsed lifter

final5-0 · Aug 6, 2007

cbarr300 said:
Grady, I thought about that...but that wouldn't explain the noise from around that area. If it was too tight, I'd imagine it'd be pretty quiet.

maybe....the exhaust valve is too tight and the intake has a collapsed lifter

Gotcha

Like others said ... just gotta go in and take a look

Grady

blksn955.o · Aug 6, 2007

I would think that the loss would be from a valve not closing all the way?

If it was a squashed lifter wouldnt I dont think it would cause that much comp. loss as it would basicly keep the valve closed longer and build more compression...like running a really small cam...IE a ton of volocity going into that cyl. from the lack of lift and dur. but still getting air flow.

Other than REALLY bad valve seals or rings I just am not seeing how a few cycles of a compression test shows low comp. from a loose valvetrain...and not an overly tight (valve not closing on seat) valvetrain.

An overly tight valve train could make noise if the oil is not getting around properly.

cbarr300 · Aug 6, 2007

Well, I just ordered my lower intake off ebay so once that comes in I'm gonna tear it down and see what I can see.

blksn: I see what you're saying. my reasoning was that it was so loose air couldn't get in so there wasn't anything to compress.

I guess I'll find out once my intake comes in.

thanks guys

blksn955.o · Aug 6, 2007

I bottomd' out a lifter the first time I setup my valvetrain with this setup. I never ran it like this I was just wondering what it would look like/do. I put what I thought (never doing that again...always get a dial and adj. PR and to it right) was the needed amount of shim after I ran the PR to the bottom of the lifter. Fount out I was wrong and just set it up the way it should be.

The valves would still open on the "messing around" test I did...also if the lifter is not pumping up it will make a good bit of racket and cause stress on the valves as they are not seeing any press. from the lifter and when it bottoms out...bang the valves go into there seats...not so good. Sounds like a few things may be out of wack...but deff. post up the results.

If your going to open it up anyway for a new lower/intake...good timing at least and you dont eat up intake gasket sets. I would REALLY think about getting a dial guage/mag. base and adj. PR and set it up correctly paying attention to the travel of the rocker tip.

cbarr300 · Aug 6, 2007

Oh, I didn't even mention the kind of rockers, etc. haha

I'm running stud-mount roller rockers on a roller cam.

I'm just gonna have to find out the hard way .....

I suppose it COULD be a blown headgasket...but I never overheated and there wasn't any detonation. If anything, with the supercharger blowing out the air (out the upper/lower intake area) I'd be running too rich. No signs of a blown headgasket and it pulls pretty decently. I'd imagine I could still romp on a stock stang and if I wasn't blowing out all my air through the vacuum leak I could prolly hang with an ls1.

no white or blue smoke...only a bit of black and I know what's causing that so I'm not worried about that.

Also, I did a coolant system pressure test and it checked out good.

which leads me to believe the noise and the low compression have to be correlated.

thanks for the opinions guys

Dino Dino Bambino · Aug 7, 2007

Noise + low compression + black smoke = Very little air getting into cylinder because intake valve lift reduced to almost zero.

compression results are in

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