22 replies to this topic

[Ethel]

It's best to remove all the plugs and give the battery a rest between testing cylinders. About a teaspoons worth should do, dribble it down the side of plug hole and allow it a few minutes to run around the piston rings.

[bmcecosse]

Should be ALL plugs out - and throttle open, hot engine, fully charged battery. Don't understand how the reading could drop to 5 bar on the 'good' cylinders with that head change! I assume you set the valve gaps after you did the swap ?

[Noodles]

Yep I did the valve gaps. I don't understand either, I have bought a new compression tester because I don't think I trust my cheap one.

Just to top it all off it decided to dump all its coolant out the bottom hose whilst in cambridge. (luckily right outside halfords)


P.S I will re-test tomorrow with all plugs out and with new tester

Edited by Noodles, 05 December 2009 - 10:23 PM.

[dklawson]

As above, hot, all plugs out, throttle wide open, fully charged battery. However, don't feel that it's carved in stone that you stop at 6 revolutions. If the gauge looks like it is still "climbing" at 6 revolutions, give it a couple more to see where you end up.

[Ethel]

I wouldn't bother about a new tester if it involves spending money - try the one you have on another car.

It's just a diagnostic tool, to help you identify faults - not to create them.

[Noodles]

Hi all, finally got round to re-testing with another tester and got these results

1 - 11
2 - 10.4
3 - 10.5
4 - 11

I think my very cheap e-Bay tester was the problem. Are these compression figures ok? So I suppose it must be something other than the bores?

[Big Guns]

As it's down a little between 2 + 3 you may have a head gasket problem waiting to happen! Having said that, when you swapped heads I assume you changed the gasket? If so the head itself may have a minor problem between the 2 cylinders.
Cheers......Dave

[Noodles]

Yer I did change the gasket. But I did notice a blueish tinge to between the 2 and 3 on the old gasket, as if it had been getting to hot?