Is my 360 done?

westie47 · Feb 4, 2020

So, I decided to do a compression check on my 360, all of the cylinders were between 110-115. When I got the car, he started it and I didn't see any blue smoke. Does this mean I have a low compression engine or is it super tired?

Don Frelier · Feb 4, 2020

Typically that would be on the low side but if they are all similar readings then maybe not.
Q.s
1. You pulled all the plugs, throttle wide open?
2. Gear reduction starter?
3. What cam? A big cam with lots of overlap will lower the number.
4. Did you check your pressure gauge against a known good gauge.

FYI my stock 77 360 had about 160 lbs with 100k on it.

westie47 · Feb 4, 2020

Don Frelier said:
Typically that would be on the low side but if they are all similar readings then maybe not.
Q.s
1. You pulled all the plugs, throttle wide open?
2. Gear reduction starter?
3. What cam? A big cam with lots of overlap will lower the number.
4. Did you check your pressure gauge against a known good gauge.

FYI my stock 77 360 had about 160 lbs with 100k on it.

I bought a brand new compression tester, the engine won't start so those readings are from just cranking, using a screwdriver on the starter relay...I have no idea of any of the engine specs...I'll be pulling it this weekend to clean it up and regasket. I may change the cam.

Ernie ingling · Feb 4, 2020

Try this squirt @10 cc oil in cylinder then test if it comes up then rings/cylinder wear. Stays the same do a leak down test to determine if valves.

33 IMP · Feb 4, 2020

If you pull the heads, measure how far down the hole the pistons are at tdc. The only way to get an idea of your compression ratio.
Edit: NOT intended as an insult, but are you sure it's a 360? Numbers on the side of the block with 360 as part of the number?

TN Mopar · Feb 4, 2020

Sounds like he took the readings with the engine cold
He said it wouldn't start
Its a good sign that they are all within 5 of each other
Don't read too much into the numbers just yet
You have enough compression for the engine to fire and apparently no dead holes
Now look at the electrical
Check for spark
If that checks out check for fuel

westie47 · Feb 4, 2020

TN Mopar said:
Sounds like he took the readings with the engine cold
He said it wouldn't start
Its a good sign that they are all within 5 of each other
Don't read too much into the numbers just yet
You have enough compression for the engine to fire and apparently no dead holes
Now look at the electrical
Check for spark
If that checks out check for fuel

I've got fuel, no spark....I ended up basically ordering all new electrical for the engine compartment....starting fresh...dropping the motor, replacing everything, then start it. I know it runs smooth already.

dvw · Feb 5, 2020

Those numbers don't bother me. They're all plenty close. A stock 360 may not even be actual 8.0-1. Bigger cam will make numbers even lower.
Doug

Is my 360 done?

westie47

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Don Frelier

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westie47

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Ernie ingling

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33 IMP

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TN Mopar

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westie47

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dvw

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