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You think its cause cams advanced 2*s? Wouldn't more valves of hit though? Shouldn't it of hit earlier? Everything turned find when I turned motor over by Hand?
If you had to you could run that piston. But I don't think I would race it. Your at the point where you need to have the pistons fly cut for valve clearence. That would mean upgrading then all. Put clay on the piston in the center cylinder and put the head back on. Adjust the valves and turn the motor buy hand a few times. Then remove the head and measure how thick the clay is where the valve hit it.
what would cause me to get to that point now? lift is still the same? only difference is the duration?
and again, why only 1 valve out of everthing? I'm not trying to disagree with you, this is just a ringing question we have, as to why its only 1 valve...we just keep thinking, if the timing was out it should mean multiple valves would be damaged...I went pretty much 3,000km on this engine with no trouble...how/why?
again, if I needed the pistons to be flycut, why is there only damage to 1 piston and 1 valve (even the intake valve on that cylinder didnt hit) and why did it take 3000km to grenade?
like I said, Im not trying to be ignorant but to me something isnt adding up...
Duration brings the valves closer to the pistons with the same lift. Timing can vary between lobes on the cam. Check the valve to piston like I explained in the post above.
what would cause me to get to that point now? lift is still the same? only difference is the duration?
and again, why only 1 valve out of everthing? I'm not trying to disagree with you, this is just a ringing question we have, as to why its only 1 valve...we just keep thinking, if the timing was out it should mean multiple valves would be damaged...I went pretty much 3,000km on this engine with no trouble...how/why?
again, if I needed the pistons to be flycut, why is there only damage to 1 piston and 1 valve (even the intake valve on that cylinder didnt hit) and why did it take 3000km to grenade?
like I said, Im not trying to be ignorant but to me something isnt adding up...
i agree with you.. even though i have no idea how far 3000kms are, if there was not enough piston to valve clearance, the damage would probably have been done a lot sooner, unless you gave it some high rpms when it happened, then its possible, but still highly unlikely.
I'll check it out...would I need to pull the motor to have the pistons flycut? or would a shop know where to flycut them?
I was going to consider going with a .045 headgasket this time, and taking another .010 off the heads (for a total of .020 off the heads)
but now I am starting to think that is a bad idea lol.
what are the odds the rod is toast now to?
i agree with you.. even though i have no idea how far 3000kms are, if there was not enough piston to valve clearance, the damage would probably have been done a lot sooner, unless you gave it some high rpms when it happened, then its possible, but still highly unlikely
3000km is roughly 1800 miles. I was steady cruising on the highway when it happened at roughly 2800rpm ish...
Alright I'm still gunna check valve to piston clearance...but I believe we found the problem....the guide backed out, the valve got hung up and smashed... Shop said valves don't get tagged like that unless they are wide open. They said if the valve sticks it doesn't take much to close it, they'll be tweaked but you won't easily see the valve is bent...secondly they said it was an instantaneous thing...neither the valve nor the seat is burnt. We do think its possible the guide was maybe backing out from the beginning...mechanic suggested there was an odd miss at idle sometimes that we couldn't pin point and thought was maybe the coils...
They also said if timing was out it would take out more valves, and if it was a weak spring it shouldve went out at a WOT pull I did a few days earlier...
Alright I'm still gunna check valve to piston clearance...but I believe we found the problem....the guide backed out, the valve got hung up and smashed... Shop said valves don't get tagged like that unless they are wide open. They said if the valve sticks it doesn't take much to close it, they'll be tweaked but you won't easily see the valve is bent...secondly they said it was an instantaneous thing...neither the valve nor the seat is burnt. We do think its possible the guide was maybe backing out from the beginning...mechanic suggested there was an odd miss at idle sometimes that we couldn't pin point and thought was maybe the coils...
They also said if timing was out it would take out more valves, and if it was a weak spring it shouldve went out at a WOT pull I did a few days earlier...
yeah, checking piston to valve clearance is always a good thing to do, but i figured it was some type of failure and not something like valve float, as the valves wont float until the higher rpms, and it would probably happen a lot sooner than ~2000 miles, unless you really do drive like a grandma.
and exactly, if it was a timing problem, only one valve would not be smashed unless you got a cam that had bad lobes. And thats exactly why I said earlier, theres no way its a valve timing problem unless you reved it pretty good
I know it wasnt valve float now...the 130# springs are pretty heavy duty to. We did think that the cam could be a possible culprit, but then again, when we turned the motor over by hand several times, we should have had a hard time, and 2) if the lobe was out, it should of made contact on startup, not 2000miles later and a few WOT pulls...
I think the rod should be ok as well, but at this point I am including it in my pricing to help me make a decision as it's still a possibility its tweaked.
honestly, it's partly my fault, the machine shop was on vacation when I did the heads, and we just swapped in the new valves and springs and visually inspected it...in hindsight if I took it in, they may or may not have been able to tell if the guide was about to go. I also dont know if the guide was either not pressed in correctly, or if it got knocked out of whack a little because of the last incident. Either way it's a learning experience...whats done is done and I gotta live with it now...so back to the drawing board and I need to figure out what I am going to do at this point.
Any suggestions are more than welcome...I'm probably going to be starting a new post about pistons shortly as I begin to pile data and crunch numbers
Depends what you wanna do. If you want to drive it, file down any raised portions on the piston, put a new valve, with a good valve seal and call it good. It's plenty driveable in that fashion. Or go crazy with unneeded aftermarket pistons and rods.
Depends what you wanna do. If you want to drive it, file down any raised portions on the piston, put a new valve, with a good valve seal and call it good. It's plenty driveable in that fashion. Or go crazy with unneeded aftermarket pistons and rods.
I've been toying with prices...everywhere is expensive, except napa seems to sell the piston for $36.99...which I might just go this route.
I'm still pricing things out...a buddy suggested I should go ahead and re-ring all the pistons while in there...
So just finished up at the speed shop...heads had bronze valveguides... The guy thinks the head overheated (I have no clue how) the valve is fused with the guide, and some of the carbon deposits on the valve have been shinned up.
He said the car was running rich (which I knew)...what the hell would cause that part of the head to overheat??...he seems to think we will need to mill the heads down a little because the head is probably warped a tad...there is some discolouration marks on various spots of the head...I'm going to bring him the head gaskets tommorrow and see if he's found anything else out...
So my truck is finally getting some work done, after 17 years, Oil pressure sensor went out and it’s located under the lower intake manifold. Have to...
Hey guys. For starters I’ve always been a big car guy, I love all types of cars and can appreciate all types of engineering. I’ve always been a Chevy...
need help finding a balancer and a replacement balancer bolt. im at a lost after confusing myself researching.
4 weeks ago
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