0 compression problem solved?

[RealFastV6]

Re: 0 compression problem solved?

Just did those fix-it studs on my buddy's SBC C10 a few months ago because they started to come loose. Did all 16 of them on the motor in the truck - tapped and screwed into the head with red Loctite. The ones we used didn't have the hex base, we doubled up nuts on the top to screw them down.

You need to be a little careful when you're tapping the existing hole for the screw in stud - the tap will not align itself in the cast iron. Once you start going, you're going. Go slow and use the neighboring studs as a guide in order to make sure you're straight.

 

[Mephisto]

Re: 0 compression problem solved?

Bear with my ignorance for a moment...

I was digging through some of my old posts from back before this happened, and I posted that I was getting 15* of knock under boost.

Now if detonation is the cause for the rocker stud to lift (if that's indeed what happened), 15* would certainly do it, no? That said, could I simply reseat the rocker stud, put it all back together, and sort out the detonation issue? Or is the stud now compromised and minimal detonation is gonna make it lift up again?

Not trying to be cheap or lazy, just never drilled into a head before and with my luck I'd end up FUBARing it and creating a bigger problem for myself haha. I suppose I could limp it down to a machine shop on 5cyl and have them do it. Provided they don't insist on removing the head.

 

[liquidswords88]

Re: 0 compression problem solved?

15 degrees of timing pulled? Will the stock ecu even pull that much? Man looking at the coolant and hearing the other info, it don't seem good. If the rocker arm is off of the valve in question and you still have zero compression in that cylinder, the head must come off. From the picture it's hard to tell if the rocker arm is still holding the valve open or not. Odds are the seat or the valve itself is damaged. It's also more than likely that there is damage to other portions of the engine. I'm new to the turbo world, so I'm also new to the detonation world. I've raced high compression small blocks for years, but as long as fuel mixture was good and timing was conservative 32-35 max. Detonation was never a real concern. In this turbo engine on a fresh 5 thousand dollar engine I have detonation anxiety. It seems to me turbos are best suited for all out 1/4 mile racing, or small displacement efficient grocery getters. For the average guy that wants a quick hot rod he can drive around and street race every now and then n/a is the way to go. Getting the most out of a turbo car seems to be more work and time than most people can or will do.

 

[RealFastV6]

It's really not a big deal. I'm talking 2 hours max for somebody that has never done it but knows their way around a toolbox.


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[Mephisto]

Re: 0 compression problem solved?

Damn, you guys are good! haha

You can see how much the stud popped up from the discoloration. So I guess next step is going the threaded route? I'm kinda thinkin if the others aren't broke I shouldn't "fix" them. Besides I don't think i'd be able to get to the studs on #5 straight on with the head still on.

 

[Don W.]

Re: 0 compression problem solved?

Well you could just pound it back in. You've almost got nothing to loose. Pound it back, set preload, start it up and see what happens. The question is why did it come out? If it stays in then you can consider additional repairs down the road. If it comes back out and you drill and tap it for a screw in stud then there is a possibility that you'll just move the problem to a different place. A bent pushrod comes to mind. Stay out of the throttle and see what happens.:2cents:

I'm tickled I just happen to see that. I must of looked at that pic 4 times before it dawned on me that the stud might have come out.

 

[RealFastV6]

Stock cam stock valve springs stock rockers?


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[It's just a six]

Re: 0 compression problem solved?

You could pound the stud back in and drill the side of the boss and pin it.

 

[Mephisto]

Re: 0 compression problem solved?

Stock cam stock valve springs stock rockers?

TBH, I have no idea. It's a rebuilt motor I bought from a forum member. He said it might have the L35 heads on it? Where are the 2 coolant holes at? :lol:

You could pound the stud back in and drill the side of the boss and pin it.

I saw a youtube video on how to do that haha. Looks like it's about the same amount of work to do that vs taping the boss for a threaded stud... although pinning is probably a little more forgiving as opposed to taping where if you're not dead on ya just effed it up. I did read something about using a slightly larger stud and pressing that in, but I don't know how you'd do that with the head still on.

 

[Mephisto]

Re: 0 compression problem solved?

Lil update here... and more rookie trial and error (but that's how we learn, right?)

So i ended up getting a tap guide and some screw in rocker studs to tap the boss vs drilling and pinning. There just wouldn't have been any way for me to get my drill in there to do it right without going at an angle or snapping the bit off.

So i go to take the nut off exhaust valve stud, and I'm ratcheting away, and turning and turning and turning... wtf? take the socket off... and the nut is still in the same spot. I grab the nut and pull up a bit and the stud comes right out. I wasn't planning on replacing that one, but I guess I am now.

I get both holes tapped, pop in the rocker studs, and.... rookie move. The studs I ordered have a hex base on them that butts up to the stud boss when you tighten them down... (I'm sure some of you are nodding about now) ya can't use those studs without milling down the boss because the rocker arm can't go down far enough to get a proper valve lash. So... back to Summit to order different studs.

The other stud pulling out by hand does have me a little concerned though.

The "glass half empty" part of me wants to assume the worst, like the head is cracked somewhere. The "glass half full" part of me wants to say the world is an imperfect place, rocker studs pull out all the time. Pop the new ones in and it'll be fine :lol:.

 

[Don W.]

Re: 0 compression problem solved?

Millions of these motors run zillions of miles without pulling studs and now you have two? Might be somethn' else going on here. Go back to Dave's post 16.

 

[Mephisto]

Re: 0 compression problem solved?

Millions of these motors run zillions of miles without pulling studs and now you have two? Might be somethn' else going on here. Go back to Dave's post 16.

Yeah i'm sure detonation is/was the root cause. I haven't run the motor at all since i found the first stud pulled up. The one that just pulled out was the exhaust stud on the same cylinder, it was still seated in there, but when i tried to remove the nut the stud was just spinning in the boss and I was able to pull it out by hand. The original one we err well you guys discovered was the intake stud and I had to use a bunch of washers to pop that one out. Being able to pull the other one out by hand while it was fully seated is what has me concerned.

I'm not gonna get the jump to conclusions mat out just yet. I'll wait till i get the right studs in, get the rockers on, and then see if they push the valves down when cranking the motor by hand without any problems or additional resistance.

Also, just for fun I ordered one of those cheapy endoscopic cameras that work with your cell phone... I took a peek inside the cylinder and it looks fine to me. Didn't see a hole in the piston or any divots that would indicate contact with the valves. So... we'll see.

 

[lil red s-10]

Re: 0 compression problem solved?

can you do a leak down test on it?

 

[0966Sy]

0 compression problem solved?

Excessive Heat/time causes the studs to come loose, it's a common problem with that style head on the 5.7. If they are a L35 casting, I'd pull the heads and have them checked, they like to crack on the exhaust valve seats. Also I wouldn't put the effort into drilling them out on the block, not worth the effort on those heads. Many of the studs protrude into water jackets so it's imperative not to drill to far. They also will require a good pipe thread sealant to keep the coolant from leaking out.

Might be worth rebuilding the short block, not sure what your condition of it is. You could always do a compression test before you pull the heads

Also, if you upgrade to a set with screw in studs, they like to pull the threads in the head from ones with neglected cooling systems. A helicoil will have to then be installed, I've done a few of those on motors before when changing over to the 3/8 ARP studs to change rockers. So if you getting a set of L35's with screw in studs and want to upgrade to 3/8 shaft rockers. Pull the studs before any machine work is done. I've pulled threads on 3 per head before. And it's not fun fixing on the block in the truck, but possible.

 

[typhoondonkey]

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Maybe....

Well first off, let me come right out and say I'm an idiot.

Sorry for wasting everyone's time asking dumb/speculative questions instead of just tearing into this bitch to see what was wrong.

I'm even more angry at myself now, because my truck has been sitting for 2 years with what I thought was a blown head gasket. Went and bought a new compression tester yesterday, pulled all the plugs, and rechecked all of the cylinders. Turns out I have a solid 150psi in 5 cylinders and 0psi in #1. With all the plugs still out, I reinstalled the #1 plug, pulled the radiator cap, and tried to turn it over for 5sec... nothing... no bubbles... So if that poor man's head gasket test is legit, then maybe the head gasket isn't blown. Today I pull the drivers side valve cover off and find this... :roll::roll::roll::roll::roll::roll:

My guess is because the motor had been sitting for so long before I put it in, that the valves got gunked up and this one was so sticky the push rod just popped out. I pulled the push rod and there's a little shine where it was rubbing on the head, but it's perfectly straight... Now fingers crossed it's not actually a burnt valve.

Reference my earlier "I'm an idiot" statement... should I attempt to reuse the same push rod? Or just go get a new one? Also, what's the torque spec on the rocker? 25ftlb? 50?

If this thing runs like a top after I fix this, for stupidity's sake I may just have to quit these trucks haha.

 

[Poconojoe]

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What do you expect, the thread has been dead for over 3 years