Leak down /compression test

I found an engine at a local wrecking yard, it is the LA 360 with roller cam (1990 dodge ram)

The engine has not been pulled yet, and it is available for $450 After it is paid for, they will do the compression test, leak down test, run it, check for smoke, noise, etc. if it passes these tests, it is considered sold as a runner. If it fails tests, it will be sold as a core and the money refunded to the purchaser.

My question is: what is considered to be good / acceptable numbers on these tests? I was told over the phone that the compression should be between 150-170, with all cylendars similar to each other. Z'at sound right?

And how about the leak down test? The guy on the phone was not a tech and didn't know.

Also, I am specifically looking for an 88-91 LA 360, as I have learned right here, on this most awesome site, that this engine will basically bolt in as a replacement for my 318, and it has the roller cam in it.

So that brings up this question: how can I tell by looking at it if it is genuinely the engine I am in search of? Will there be a number cast into the 360 block stating that it is the roller model?

HELP!!

And thanks!

Compression tests are ok but the leak down test is the tell tale on the condition of the engine. Up to 25% leakage is still a solid engine. 25 to 40% is considered moderate and shows it has some wear that will need addressing in the near future. The good thing about the leak down is it will let you know where the issue is, air coming out the carb- leaking intake valve. air out the exhaust leaking exhaust valve and air out the dipstick would be worn rings or other piston issues.

as far as the compression test.....the numbers should ALL be over 150psi....and there should be less variation than 5-8psi across the board.

should look like:
1- 152
2- 155
3- 151
4- 152
5- 151
6- 152
7- 153
8- 151

long as the block casting date is 88/89/90/91 and it has 3 6 0 cast into the other side.....you should be Golden.

The 89 model year was the first year for the 360 roller cam motor.

Thanks, guys

As far as the leak down test results go, I'm not sure I fully understand. Are they going to tell me at the salvage yard if it is, say, 25%, where the leak is coming from? I am likely not going to be able to be there for the test.

Kelly,
Thanks for the reply to the questions I asked in the "private messages" section. I didn't see your reply 'til after I posted this thread. I think it would be useful to copy /paste it here. I know you have gone over this subject before, but it may likely be very useful for others, too.

bighammer said:

Thanks, guys

As far as the leak down test results go, I'm not sure I fully understand. Are they going to tell me at the salvage yard if it is, say, 25%, where the leak is coming from? I am likely not going to be able to be there for the test.

Kelly,
Thanks for the reply to the questions I asked in the "private messages" section. I didn't see your reply 'til after I posted this thread. I think it would be useful to copy /paste it here. I know you have gone over this subject before, but it may likely be very useful for others, too.

Click to expand...

Hopefully they will. If they don't ask them where the leakdown is going. The tell-tales of a leak-down test are not only the numbers but where the air is leaking past. The dipstick means passed the rings (normal). The intake or carb=passed the Intake valves, and out the exhaust means passed the exhaust valves.

If you buy a L-D testor I recommend the OTC ($45). It's a handy tool.

The fastest way to see if it's the good one is see if it's throttle body injected. It will have "360" cast in above the starteron the driver's side, and the casting date on the passenger side will be '88 or newer, and it will have the TBI on it.