Bent up stuff

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VonCramp

VonCramp

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I am not sure how to start this thread, but my motor was running perfect earlier today. Then, my machinist buddy came over and disconnected the pcv and vacuum advance. Advanced the timing way up. Motor started running real rough and he said to drive it anyways. Then, it started running real bad. Loss of power across the board. Got the car home. All pushrods bent. Two broken valve springs on the #2 cylinder. I am/was running 1.6 roller rockers. Comp Cams solid roller cam and lifters .570 lift. I DID NOT over rev the motor ever. Why did everything just bend and break suddenly. I promise the motor was not wrapped up at all.
 
VonCramp said:
I am not sure how to start this thread, but my motor was running perfect earlier today. Then, my machinist buddy came over and disconnected the pcv and vacuum advance. Advanced the timing way up. Motor started running real rough and he said to drive it anyways. Then, it started running real bad. Loss of power across the board. Got the car home. All pushrods bent. Two broken valve springs on the #2 cylinder. I am/was running 1.6 roller rockers. Comp Cams solid roller cam and lifters .570 lift. I DID NOT over rev the motor ever. Why did everything just bend and break suddenly. I promise the motor was not wrapped up at all.
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Motor is 340 with pro comp heads.
 
The "running rough" is your first sign of bad timing. What your buddy did aside. Lets start with some more specs.

Give us full motor details. As much as possible. Including mileage, any passes, highest rev (that you know of) and what not. Increasing timing increases possibility of many things. Including detonation and such. What do your plugs look like? Have you pulled anything else out of there?

EDIT: Don't let your buddy touch your engines anymore.
 
Lustle said:
The "running rough" is your first sign of bad timing. What your buddy did aside. Lets start with some more specs.

Give us full motor details. As much as possible. Including mileage, any passes, highest rev (that you know of) and what not. Increasing timing increases possibility of many things. Including detonation and such. What do your plugs look like? Have you pulled anything else out of there?

EDIT: Don't let your buddy touch your engines anymore.
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Motor is '72 340. Highest rev was two weeks ago at 5000 rpm. All plugs fouled on passenger bank when pushrods bent today. New cam on 20,000 mile rebuild. Cast flat tops. Aluminum pro comp heads. Pro Comp intake and carb. Motor has not been ran hard with new cam. Installed new Comp Cams Springs Open load springs.560.
 
I do recall hearing a snapping sound while my friend was "timing" the motor which must have been the springs breaking.
 
Why in gods name did he do that? I'm sure your engine was detonating like crazy with him advancing the timing like that! What was his reason?
 
sure he didn't do something so stupid like that on purpose? exactly why NO BODY on this planet has or will EVER touch my **** other than me.


I gotta say though, you should have never driven it like that. that wasn't very smart on your end either.....
 
Sound like your machinist buddy is going to be doing some free machine work for you!
 
SGBARRACUDA said:
I have a feeling there is more to this story!
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Yes. - There are a lot of details left out. Why did Voncamp's buddy disconnect the PCV, vacuum advance, and advance the timing if the car was running perfectly? When was the 'new cam' installed? If it was just installed earlier that day I'd guess the lash wasn't set properly and the damage progressively got worse the longer it ran. Messing with the ignition timing could have made it run like crap but I don't think it would have bent those pushrods.
 
SGBARRACUDA said:
I have a feeling there is more to this story!
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I am not purposely omitting details. I am to my knowledge including everything I know. One detail I can thing of is that he did set the lash what seemed like half-*** to me by eyeballing the opening and closing of the valves. For some reason he is a firm believer in omitting the pcv and vacuum advance. Both of which I was running prior to him tuning it. He pulled both off and plugged the ports. Advanced the timing. Motor started idling real rough. He said drive it to see what it felt like. I trusted him because he knows a lot about machining. I had no clue I was in for some serious engine damage. In a matter of minutes the pushrods bent. Two broken valve springs and fouled plugs on passenger bank. I have not been running car hard because I was waiting to run it at the strip soon.
 
1967 'cuda said:
Yes. - There are a lot of details left out. Why did Voncamp's buddy disconnect the PCV, vacuum advance, and advance the timing if the car was running perfectly? When was the 'new cam' installed? If it was just installed earlier that day I'd guess the lash wasn't set properly and the damage progressively got worse the longer it ran. Messing with the ignition timing could have made it run like crap but I don't think it would have bent those pushrods.
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I agree with what you are saying. He disconnected everything because he said my motor didn't need it. I always do my research and I know street motors like vacuum advance. I also know that pcv is needed to relieve crank case pressure. I believe he screwed up on the valve adjustment and the timing fiasco just finished it off. Not sure what else I can say.
 
I really don't understand his eliminating of the PCV, it's there to relieve excess crankcase pressure. The advance on the distributor I don't run on a street strip set up.But then I set up the centrifugal advance different. But when he advanced the timing to the point of a noticeable change in the idle quality? What he did was pull the pin on the grenade! I suggest you pull the engine down to see the extent of the damage. And change machinist at the same time.
 
VonCramp said:
I agree with what you are saying. He disconnected everything because he said my motor didn't need it. I always do my research and I know street motors like vacuum advance. I also know that pcv is needed to relieve crank case pressure. I believe he screwed up on the valve adjustment and the timing fiasco just finished it off. Not sure what else I can say.
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Sorry to hear about the damage but it's not fatal. I wouldn't just replace the pushrods though. With two broken springs there's a chance the valve train was binding and causing the springs to over compress.

You'll want to make sure the valves weren't contacting pistons also. - Hope none of them got bent.
 
VonCramp said:
I agree with what you are saying. He disconnected everything because he said my motor didn't need it. I always do my research and I know street motors like vacuum advance. I also know that pcv is needed to relieve crank case pressure. I believe he screwed up on the valve adjustment and the timing fiasco just finished it off. Not sure what else I can say.
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The valve lash was done two weeks ago. I installed the roller cam because I wanted a bigger cam. My machinist friend's boss who builds dirt track motors said to disconnect the pcv and advance because they are just vacuum leaks waiting to happen. True story.
 
Sounds like your valves met face to face with the pistons. At this point I would pull the heads and go from there.
 
VonCramp said:
The valve lash was done two weeks ago. I installed the roller cam because I wanted a bigger cam. My machinist friend's boss who builds dirt track motors said to disconnect the pcv and advance because they are just vacuum leaks waiting to happen. True story.
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I suppose on a dirt track car with all the mud getting slung around he might have had bad experiences with hoses coming off but that's a way different environment than a street or strip car lives in.
 
1967 'cuda said:
Sorry to hear about the damage but it's not fatal. I wouldn't just replace the pushrods though. With two broken springs there's a chance the valve train was binding and causing the springs to over compress.

You'll want to make sure the valves weren't contacting pistons also. - Hope none of them got bent.
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Silly question but can the valves be checked while heads are still on motor?
 
1967 'cuda said:
I suppose on a dirt track car with all the mud getting slung around he might have had bad experiences with hoses coming off but that's a way different environment than a street or strip car lives in.
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Nothing about hoses coming off. Just says that the carb port is a vacuum leak at pcv and the vacuum advance is not needed on a street/strip motor (even though my motor ran great with it.)
 
Sure you can. either replace the push rods and adjust the valves and do a compression test. Or remove all the push rods and rig up a hose to air up each cylinder through the spark plug hole and check( listen) for air coming out of the carb or exhaust
 
At the expense of hurting some feelings, here goes. First, I agree with 73AbodEE; Nobody messes with my stuff. I help a LOT of people with their stuff, but I always refuse offers of help from others. When I need an extra pair of hands, I get my wife to help me. (she is actually a pretty good helper). Second, why on earth did you drive it when it was running so poorly? It doesn't matter that you think this guy knows more than you. If the car WAS running fine and suddenly runs like CRAP, don't drive it. Tell the other guy thanks, but no thanks; put it back like it was. There is plenty of blame to share here, but the bottom line is that if the car WAS running fine and suddenly ISN'T, don't drive it.
 
I
SGBARRACUDA said:
Sure you can. either replace the push rods and adjust the valves and do a compression test. Or remove all the push rods and rig up a hose to air up each cylinder through the spark plug hole and check( listen) for air coming out of the carb or exhaust
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I was just thinking that. Thanks!!!
 
harrisonm said:
At the expense of hurting some feelings, here goes. First, I agree with 73AbodEE; Nobody messes with my stuff. I help a LOT of people with their stuff, but I always refuse offers of help from others. When I need an extra pair of hands, I get my wife to help me. (she is actually a pretty good helper). Second, why on earth did you drive it when it was running so poorly? It doesn't matter that you think this guy knows more than you. If the car WAS running fine and suddenly runs like CRAP, don't drive it. Tell the other guy thanks, but no thanks; put it back like it was. There is plenty of blame to share here, but the bottom line is that if the car WAS running fine and suddenly ISN'T, don't drive it.
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He was acting pretty butt hurt when I said it was running bad. Hindsight of course on the driving while running badly. I know better now obviously. As far as helpers, yea the first thing people want to do is set tools in the fender wells. Scratching paint and losing tools. I am very careful and keep a tool cart nearby.
 
SGBARRACUDA said:
Sounds like your valves met face to face with the pistons. At this point I would pull the heads and go from there.
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This ^^^^^ is your only option to assure it will be right again. Bent pushrods happen only one way. Valve to piston clearance.
 
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