96 LT1 compression test
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96 LT1 compression test I want to run a compression test before i get too carried away with this newly acquired LT1. (Sitting on a stand in my garage) I have a book coming but hoping you guys could help in the meantime. It is supposed to be completely stock, has pretty much everything in place to my knowledge (ECU, wiring, all sensors etc) I know to take all plugs out and block the throttle body wide open. I am also going to fill the oil pan with oil as it is currently drained. Also there is no fuel source.
My question is, is there anything I need to do to protect electronics, like ground out the ignition or anything? I am thinking there will be no spark anyway but just want to make sure as I am not familiar with LT1. I am going to bump start using starter motor and trigger bump starter. Also is there anything else I need to do to perform this test correctly?
My question is, is there anything I need to do to protect electronics, like ground out the ignition or anything? I am thinking there will be no spark anyway but just want to make sure as I am not familiar with LT1. I am going to bump start using starter motor and trigger bump starter. Also is there anything else I need to do to perform this test correctly?
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Thread Starter
On The Tree
Joined: Feb 2018
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Thread Starter
On The Tree
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From: PDX-OR-USA
Plugs out,
Give each hole just fine spritz of oil if it hasn't run in a while.
a Leakdown will tell far more than just the compression test.
And you can use a leak down tester for both checks.
Just turn with the starter, and I would make sure there is oil in the engine..
Give each hole just fine spritz of oil if it hasn't run in a while.
a Leakdown will tell far more than just the compression test.
And you can use a leak down tester for both checks.
Just turn with the starter, and I would make sure there is oil in the engine..
Thread Starter
On The Tree
Joined: Feb 2018
Posts: 163
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Plugs out,
Give each hole just fine spritz of oil if it hasn't run in a while.
a Leakdown will tell far more than just the compression test.
And you can use a leak down tester for both checks.
Just turn with the starter, and I would make sure there is oil in the engine..
Give each hole just fine spritz of oil if it hasn't run in a while.
a Leakdown will tell far more than just the compression test.
And you can use a leak down tester for both checks.
Just turn with the starter, and I would make sure there is oil in the engine..
I wouldn't worry about using oil for the cylinders at first. If you run into a bad cylinder you can then use an oil pump can and put in a few squirts into the cylinder to see if compression rises. If it does it's most likely the rings are worn. If not then you may have valve/top end issues. Also if there's a manifold and throttle body on this engine, block open the throttle blades.
Worn out cylinders are usually on the bottom side of the cylinder from both gravity and piston thrust. That's why straight angle engines last a bazillion miles. The cylinders wear evenly. When you put in oil gravity will take it exactly where it needs to go.
Worn out cylinders are usually on the bottom side of the cylinder from both gravity and piston thrust. That's why straight angle engines last a bazillion miles. The cylinders wear evenly. When you put in oil gravity will take it exactly where it needs to go.
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I wouldn't worry about using oil for the cylinders at first. If you run into a bad cylinder you can then use an oil pump can and put in a few squirts into the cylinder to see if compression rises. If it does it's most likely the rings are worn. If not then you may have valve/top end issues. Also if there's a manifold and throttle body on this engine, block open the throttle blades.
Worn out cylinders are usually on the bottom side of the cylinder from both gravity and piston thrust. That's why straight angle engines last a bazillion miles. The cylinders wear evenly. When you put in oil gravity will take it exactly where it needs to go.
Worn out cylinders are usually on the bottom side of the cylinder from both gravity and piston thrust. That's why straight angle engines last a bazillion miles. The cylinders wear evenly. When you put in oil gravity will take it exactly where it needs to go.
If I were to guess with a stock cam it'd be maybe in the 180 to 200ish area? I remember doing one on my car when it had about 30K miles on it with a 211/219 cam and LPE heads and it was in the 205-210lb area. Did one again with the same heads and a GM847 cam at 90Kish miles and all cylinders were right around 180. What is also important is that all cylinders are within 10% of eachother.
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If I were to guess with a stock cam it'd be maybe in the 180 to 200ish area? I remember doing one on my car when it had about 30K miles on it with a 211/219 cam and LPE heads and it was in the 205-210lb area. Did one again with the same heads and a GM847 cam at 90Kish miles and all cylinders were right around 180. What is also important is that all cylinders are within 10% of eachother.