2010 THP 150BHP Compression test

[glennedb]

Hi all, does anyone know what the compression output is for this engine if i do a compression test..thanks in advance.

[BenS]

11:1 I think. It's probably in the manual.

[Jamie@SPTuning]

Just measure all cylinders and compare results, a bad cylinder will show straight away.

[glennedb]

Thanks all.

[Jamie@SPTuning]

Ratio is 10.5:1

[Czar]

Hi all, does anyone know what the compression output is for this engine if i do a compression test..thanks in advance.

What your asking is, does anyone know the cylinder compression pressure, and not the static compression ratio !!

To make things easy, a simple equation of, if you know the static compression ration, which as Jamie has already mentioned, is 10.5:1

The equation is; we all know that 1 atmosphere is 14.7 psi at sea level, so we take 14.7 multiply by the first number of the compression ratio, which in this case is 10.5 and either leave it at that, or divide by the last number of the ratio, which is 1

So we should have:

14.7 X 10.5 = 154.35 psi we can leave it at that or divide by 1 your choice, LOL

If you do get a cylinder with a low psi pressure, this does not mean it's developed a fault, you have to remember that the piston rings rotate continuously during operation, so you may end up with all the expansion gaps alighned, given a zero compression reading !!

Sometimes the piston rings become stuck from carbon debris, again they could well be stuck with all the expansion gaps alighned, try a few drops of oil directly into the cylinder/s run the engine to full operating temperature, retest, if there is still a low or zero pressure cylinder, perform a leak down test, then repeat or repair as necessary.

[glennedb]

Cheers Czar for that calculation...but im just a steelworker so im just sat here with spit dribbling down mi chin........But yes it was the psi reading i was after...thankou!