leakdown test...asking for tips and tricks

[mark '87 930]

I will be performing a leak down test in the weeks to come and have a few questions on how to ensure certain items are done correctly.

1) With the engine hot.. do you still remove the IC and all else? or just get in there. I ask because I am curious at how warm the engine needs to be for the test to be done well

2) What is the simplest and most accurate way of finding TDC for each cylinder? Should I remove the Dis. cap and check?

3) Those plugs are going to be hot.. should I very slightly loosen them before I warm up the engine?

[Eagledriver]

You only need to remove what is in the way of getting the plugs out and the tool attached. Find TDC with the marks on the pully and the direction the rotor is pointing. Once you find one you can do the others in the firing order only having to turn the crank 120 degrees at a time. You don't need to loosen the plugs first unless you think some of them are going to be "stuck".

-Andy

[Johan123m]

I'm going to do the same thing and I want to put another Q to the list...

- Can a leak-down test be correctly performed with the engine out of the car and not hooked up?

[Determined]

Bump, I had the same question as Johan.

Alex

[haycait911]

yes, you can do a leakdown with the engine out. but, the results won't be quite the same or as accurate as if the engine was at operating temp, although should still give you a good idea what's going on inside. Don.

[Rick V]

If you perform a leakdown test on a cold engine your numbers will be high. The rings and such woun't be "expanded" along with the rest of the engine bits.
If you do it on a cold engine you are going to be looking for simular numbers not low ones.
Don't worry Mark, where the engine is hot, you won't be having to put your hands on. Just grab a set of "mechanics" gloves to help with the plug temps.

[mark '87 930]

Thanks for all the input. My biggest thing was the TDC.. but with the lines on the crank and the distributor, I should be fine.

Thanks again.

[rattlsnak]

Why are you doing a leak down? Is there a problem with your performance/engine?

[mark '87 930]

Not really... When I got the car, the lowest number was an 11%.. and the rest were between 3% and 5%.

It's just something I want to do (kinda like a make work project)! I'm not sure if the car has ever been apart other than a valve adjustment, so I'm curious about the ondition of the heads.

I plan to do a compression test as well. Overall, I'm not unhappy with the performance at all, it's actually great, I just want to make sure everything is ok. No engine rebuilds for me...not now anyhow, summer is just peakig it's head!

For reference, the car has 98K miles on it.