NO COMPRESSION....wtf?????
What I was saying about 180 out was that as long as the dots are lined up it doesn't matter if you switch the cranks compression and and exhaust cycles. You can't have the cam at 12 and crank at 12 or you will have bent valves.
Originally Posted by strokedls1
What I was saying about 180 out was that as long as the dots are lined up it doesn't matter if you switch the cranks compression and and exhaust cycles. You can't have the cam at 12 and crank at 12 or you will have bent valves.
Put the crank dot at 12 and the cam dot at 12. Now turn the crank 1 complete revolution. Where is the cam dot now?
Put the crank dot at 12 and the cam dot at 6. Now turn the crank 1 complete revolution. Where is the cam dot now?
Why is this so hard to understand?
Thread Starter
Joined: Feb 2004
Posts: 1,131
Likes: 4
From: Franklin MASS
Well its not that hard to understand....but I am not understanding why its just not firing. Once I get it off the trailer, I can do a compression test on it, and see what its doing
hey an ignition module will cause the same thing. it will fire a couple times and stop sending fuel. my car does it every 2 months or so. i'll just come back the next day and it starts fine. i'm almost postive its the module on top of the column. there is an adjustment on there 2 if you lossen the 2 bolts holding it on.
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Verdad Gallardo You should hear it spin. I swear when I heard it, I though the starter didn't engage. And the only thing was spinning was the starter. I was suprised to see the engine spinning.
Depending on the pushrod length, you could shim the rockers up to take away some preload. Now I get what your saying 2xLS1. Had a hard time visualizing it. With no compression it definitely won't start.
alright fellas...Im helping Rob down in NC and here is what we've got after tearing it down today. We hooked up my vaccum guage and turned it over. Needle didnt even flinch. Hooked up the complression guage, same results. Loosened the rockers on number 7 and left the compression guage hose screwed in the plug hole and blew a lung full of air into the cylinder. I didn't even get a hint of cylinder pressure. I could hear the air coming out. So with that in mind and it being a pretty new engine, I'm thinking the valves are bent. Im not real familiar with LS1s, only worked on a couple, but mechanics are mechanics. However, is there anything we are missing? We only did it on one cylinder but the way the engine sounds when you turn it over we only needed one cylinder. Need you thoughts ON THE PROBLEM AT HAND.
TECH Addict
Joined: Dec 2001
Posts: 2,907
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From: Bergen County, NJ
Originally Posted by 2xLS1
I think you using the term No Compression is confusing a lot of people here. Have you checked the "compression" with a compression tester. Are you just trying to say you are getting no combustion as in it's not firing? Sensors have nothing to do with compression. Only piston movement and valve events control that.
We checked the compression by the guage method. The engine spins as if the timing chain were broke but the rockers are moving. We haven't checked for spark and we can smell fuel on the plug we took out
Originally Posted by wicked_95z
alright fellas...Im helping Rob down in NC and here is what we've got after tearing it down today. We hooked up my vaccum guage and turned it over. Needle didnt even flinch. Hooked up the complression guage, same results. Loosened the rockers on number 7 and left the compression guage hose screwed in the plug hole and blew a lung full of air into the cylinder. I didn't even get a hint of cylinder pressure. I could hear the air coming out. So with that in mind and it being a pretty new engine, I'm thinking the valves are bent. Im not real familiar with LS1s, only worked on a couple, but mechanics are mechanics. However, is there anything we are missing? We only did it on one cylinder but the way the engine sounds when you turn it over we only needed one cylinder. Need you thoughts ON THE PROBLEM AT HAND.
Originally Posted by DanZ28
Also, on the whole 180* out thing, can someone tell me how that could be ok?
If youre not getting a hint of compression with a rocker pulled, its gotta be bent valves (unless you have a hole in every piston, which is rather unlikely). Time to pull the heads and inspect the damage. My guess is it wont be pretty.
Originally Posted by wicked_95z
alright fellas...Im helping Rob down in NC and here is what we've got after tearing it down today. We hooked up my vaccum guage and turned it over. Needle didnt even flinch. Hooked up the complression guage, same results. Loosened the rockers on number 7 and left the compression guage hose screwed in the plug hole and blew a lung full of air into the cylinder. I didn't even get a hint of cylinder pressure. I could hear the air coming out. So with that in mind and it being a pretty new engine, I'm thinking the valves are bent. Im not real familiar with LS1s, only worked on a couple, but mechanics are mechanics. However, is there anything we are missing? We only did it on one cylinder but the way the engine sounds when you turn it over we only needed one cylinder. Need you thoughts ON THE PROBLEM AT HAND.
Looking back at the original post, a short block was installed. Was there a cam already in the block or was a cam installed? Just trying to figure how the cam timing got off and bent the valves.
My guess is the cam was installed wrong and at a minimum you have 8 bent intake valves. I hope no major damage was done to the pistons or short block. Pull the heads and let us know what you find.