Leakdown , compression , or both?

[rebar]

Im looking at buying a used 85 vmax and want to check out the engine as well as I can.

Im pretty sure I know how to do a compression check but not sure on the leak down or if I need to do it.

Which test should I do? And does anyone have a link which discribes both or the leak down test?

Is there any other tests I can or should do to be sure the motor is healthy?

Thanks

 

[one2dmax]

A compression test will normally be enough though a leakdown can show other problems. It's hard to do the leakdown test (or takes more time). Biggest thing is take it for a ride. Get it warmed up and run it hard and shift it hard. If it seems to run well and not a big smoker then i'd probably say you're good to go.
Sean

 

[dannymax]

Im looking at buying a used 85 vmax and want to check out the engine as well as I can.

Im pretty sure I know how to do a compression check but not sure on the leak down or if I need to do it.

Which test should I do? And does anyone have a link which discribes both or the leak down test?

Is there any other tests I can or should do to be sure the motor is healthy?

Thanks

This covers it pretty well rebar:
http://www.dietersmotorsports.com/Compression-leakdowntest.htm

 

[rebar]

This covers it pretty well rebar:
http://www.dietersmotorsports.com/Compression-leakdowntest.htm

Good link thanks! I want to do one or the other and dont care about the time taken. The leak down must be better?

A few things not stated in the leakdown steps is how many psi do you pump it up? How long to wait for your second pressure reading?

It says you need to measure volume of air? :confused2: CFM ? or pressure loss?

 

[dannymax]

Good link thanks! I want to do one or the other and dont care about the time taken. The leak down must be better?

A few things not stated in the leakdown steps is how many psi do you pump it up? How long to wait for your second pressure reading?

It says you need to measure volume of air? :confused2: CFM ? or pressure loss?

I was wondering those things too but have only done compression testing and not C. L. T.'s. Think it might be a good idea to learn how tho.