LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

heeelp with newly installed cam

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Old Nov 11, 2007 | 01:59 PM
  #16  
87bandit's Avatar
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From: Palm Harbor, FL
possibly cam timing is incorrect and you bent some valves
Old Nov 11, 2007 | 02:26 PM
  #17  
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When you installed it, did you run it straight up? ( Dot-to-dot ) You sure you werent off a tooth or anything? Did you degree the camshaft when you installed it? I would use a compression gauge on each cylinder. It will tell you if you bent a valve/have a compression leak elsewhere. If you find a problematic cylinder, dump a little oil in that spark plug hole, and try it again. If the compression spikes up, you have a ring problem, if it is the same (low) you likely bent a valve from some bad valve timing/piston to valve issue.

You sure you didnt break a timing chain? When a timing chain breaks, it will crank and crank and crank and not as much as sputter, and sound weird.

Check your fuel pressure.

Check for spark at the plugs.

Try holding a long screwdriver to your ear while you have someone else crank it, and use it as a stethescope to help determine where the sound is coming from.

Try disconnecting your serpentine belt and cranking it. If you have a loud squeeling, maybe one of the accessories locked up.

If none of this helps, your probably best off removing the waterpump/timing cover first. Then the intake manifold if you can't find anything.

Try not to get frustrated. I know it sucks when **** goes wrong. It happens though. And its part of building cars/engines. I had a expensive build on a hi-po 125CC motor seize back up in about 10 seconds because a TINY piece of old circlip got lodged between a ring and the cylinder. The blown motor still ran, so we assumed the circlip was blown out the exhaust port. Lesson learned lol ...

Good luck with it all.
Old Nov 11, 2007 | 02:32 PM
  #18  
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From: Engineerland
From your thread in the apearance section it looks to me like you have some sort of a leak too, in one of the shots you have fluid slung on your intake elbow may just have been something that got on the belt durring the swap but i just thought i'd mention it.

Other than that make sure everything is plugged in good, the screeching is probably just the belt with fluids on it. How hard is it to restart when it kicks off? and does it run the same at idle as it did before?
Old Nov 11, 2007 | 03:11 PM
  #19  
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Actually, Check to make sure all your vacuum lines are on. I had a similar issue where my brake booster came off. The car would NOT idle. But would start if you held it at part throttle. Ran like total ****. Givwe it too much gas, and it would die. Took me a few minutes, then I realized the brake booster somehow slipped off ( Possibly from a backfire? Which you may have had with a cam, no tune, and revving it up that high ) so check to see that theres no vacuum leaks anywhere. Check the vacuum lines, brake booster, etc.

Good luck with it all. Hopefully it is something stupid.

How tight did you adjust the valves? If you didnt pump up the lifters first, you could have the valves adjusted to tight. Once you started it, it idled OK, but the lifters pump up with oil once its running. You now would have way too tight of a valve lash. Rev it high, the valves dont close all the way and it'd possibly sputter and die. Then be hard as hell to restart once their all pumped up and adjust too tight ( Valves cant close all the way, so you have poor compression & vacuum.)

Just some things to consider.
Old Nov 11, 2007 | 03:14 PM
  #20  
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From: Summerville, SC
Well we checked damn near everything, and we've ordered a new opti. The squeal we believe was caused because the sensor on the front of the h2o pump wasn't tight and it was leaking antifreeze onto the belt, and onto the opti as well. The fuel pressure was fine, the compression was good as well. Today it wouldn't start at all, so i will update when the opti gets in.
Old Nov 11, 2007 | 06:40 PM
  #21  
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From: Chicago, IL
I dont think it is vacuum leak, or it would die at idle most likely. I am not an expert but maybe you need some more fuel than stock!
Old Nov 11, 2007 | 09:10 PM
  #22  
HardcoreRM125's Avatar
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From: Pgh, PA
vacuum leaks do make it stall at idle. I thought he said someone had to give it throttle to get it to start, and it would only idle holding the throttle on, but too much throttle and it would die out ?

His solution with the Opti does seem reasonable though.
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