The Rover-Landers of BC

I just did a pressure test on my 2.25l series IIa and I was wondering what was a normal amount of pressure for these engines... I got 85psi +/- on average and the wet test proved to be about 90psi +/-...

Was the engine hot when you did the test? You did hold the throttle wide open during the test as well - right? I think that really good numbers for a 7:1 head are about 140 and for an 8:1 head somewhere around 160. If I saw 120's across the board on a used engine I would be content.

Make sure you remove all plugs and hold the throttle wide open. If the numbers are not as high as you would like,try the test again with a little oil. At least then you should know where the problem lies.

Mike

The engine was hot, but I did not have the throttle wide open nor did I have all the other sparks plugs, I'll try that tonight.

Thanks!

Wow this is exciting, , can some one tell me what is going to make it go round with all the plugs out. I remember at a founder DAY, we used my truck with a crank in a contest. and kept taking plugs out to see who could start it fastest, and i think we got down to the winner with 3 out,. but it wasnt going to run with 4 out i didnt think. , . lol. oh well will watch the wonders of modern mechanics unfold i guess...rcmx

Good advice to have the plugs out, and the throttle open when doing a compression test as you'll get the truest assessment of each cylinder if everything else is just freewheeling along.

But you should do a "dry" compression first, and a "wet" second. Dry being after the engine has run and therefore any oil collected in the cylinder has been combusted, wet being a couple of shots of oil from an oil squirt can immediately before the test.

In my experience, if the results of both wet and dry tests are within about 20 pounds, and all 4 cylinders are similar within about the same range, (and that range is around 120), your compression is OK. Like John said, higher on a newer, higher compression engine, but on a used engine, 120 would be quite acceptable.

If there is a significant difference between wet and dry readings, it usually means your rings are worn. If there are one or two cylinders that are significantly lower than others but not significantly different on wet or dry tests, it usually means a burnt valve. If two side by side cylinders have low wet/dry readings it often means a burn out of the head gasket between two cylinders.

Obviously there are situations where more than one thing is wrong and the compound readings can't be figured out until the engine is pulled apart.

Happy testing.

Dave

If you don't take all the plugs out you can get false readings on a blown head gasket for example.

Mike

i think the part i was missing was the turning over with just the starter, it has been 7 years. since we did it, so i forgot, . oh well. rcmx