Here's the deal...I have a 75 2ltr and a 76 2tr? I only need one...going to sell the other one. Both are FI. Supposedly the 76 was just rebuilt...actually I would call it freshened-up i.e. new rings.

I did a leak down test on the 76 and all cylinders were about 3-5 % leakage...OK, then I do the 75 and it has even less leakage..NO WAY...that can't be right. They both can't be in that good of shape...must be doing the test wrong.

Am I doing this leak down correctly?
1) Bring piston to TDC
2) Air compressor is set to 100 PSI
3) throttle body open
4) Connect tester that has two guages
5) According to the directions I turn the knob cw (bottom of first gauge) until the guage on the right reads "0" (far right at end of yellow zone).
6) Leave at constant pressure and then watch the needle. Read the amount of leakage.
Does the numbers on the gauge on the left mean anything?

I know the motors are suppose to be warm, but I'm primarily looking for a differential between cylinders this should be OK test.

Question 1: Am I doing the test correctly?
Question 2: What else can I do to help decided which motor to keep?
No need to post a picture of either motor (unless you want)..they look pretty much identical. I'm leaning toward the 75 just because it looks like it has never been touched...not knowing what kind of job the mechanic did on the 76.
I need your advice!

Do you have a stop watch???

Cause your gunna need one....

Time VS Pressure drop..

Go google and search HOW TOO use A Leak down tester. yada, yada...

That will keep me from writing a whole article on the subject.

As the results are to a degree... Subjective

If the engine doesn't have a stock ring pack. And they are set up loose for a purpose, or the rings have no oil on them, or a seat/valve has a little piece of carbon on it. Again... you may get erroneous data.

Google da crap out of it.... Cause a leak down test can do more thaqn most people think it can.........

C

C

If you've been around long enough you should know you shouldn't get rid of any of them. Thars gold in dem dare motors.

First time I've seen someone wanting to find something wrong with one of their engines

Leakdown tests are a great way to judge and engine's integrity.. Unfortunately unless the engine is warm the results are generally not accurate..

Warm and @ TDC- thats the rule

I would figure out which one of them has the best chance of survival and use it but also keep the other until it proves itself...

Hell I'm in the process of building a spare engine for my teener.. I would keep both engines, the one not being used I would freshen it up and use it when the one in the car needs to be pulled and worked on. I'd keep it.

with Strat. Keep it. You'll need it someday. Back on the road in one day!!!