Club 80-90 Forums

no need to buy any tools to pop a rocker cover off..

The tappets look ok, as far as I can tell. Nothing loose or untoward.

Melvin

Well, popped down to halfwits where they tried to sell me a tyre pressure guage!

So, starting with no. 1 cylinder - cos the plug's already out - and getting no reading or even a flicker of the needle. So I'm either not doingit right, or thing are worse than I thought! Going to google it and see what I've missed (the instructions are very basic).
Melvin

Batteries are a bit flat from yesterday as well, so may need to do this tomorrow.

Melvin

OK, I think Ive got it, all the plugs need to be out! The crap instuctions on the packaging appear to suggest one plug out at a time (this actually makes more sense to me, but then what do I know!)
Melvin

Yeah, all plugs out... Has to turn over at a fair rate of knotts to register a pressure reading!

OK, maybe I'm doing this wrong, the insructions with the tester (a Gunsen) are very basic, and it's quite tricky to screw into the plug holes, with the rubber hose and the dial bit flapping about, and maybe the battery isn't up to it any more! (Or the engine is really dead!)

Anyway what with the weather, the above difficulties and my increasing frustration , we've tried the tester on 2 cylinders (randomly 1 and 4) and not got so much as a flicker of the needle! Shouldn't we get some sort of reading? Even if it was really low? After all 1 and 2 cylinders are sucking petrol!

Melvin and the white elephant

Melvin,
This little online guide may help a bit. Must admit never bothered to do one, all my failures have been fairly major and obvious

Compression Test Tips

Mike

Thanks for the link. Battery's on charge again!

Melvin

Still no reading. 2 charged batteries, not a flicker. Anyone got a working 1.6 for sale?

Melvin

you should get some kind of reading regardless... with one plug out (the one your testing ) or all four.... put your thumb over the plug hole and get someone to turn the engine over , manually if need be and see if there is any pressure at all..

Even with no compressions the gauge should flicker. Have you got the pressure release screw near the gauge done up. You should also have the throttle wide open when checking compressions.

Thanks for the replies

Even with no compressions the gauge should flicker. Have you got the pressure release screw near the gauge done up. You should also have the throttle wide open when checking compressions.

The compression tester has a sort of springy button on it, is that what you mean? have tried with this button both depressed and not.

you should get some kind of reading regardless... with one plug out (the one your testing ) or all four.... put your thumb over the plug hole and get someone to turn the engine over , manually if need be and see if there is any pressure at all..

Just tried my thumb over 1 and 4 whle engine was turning over and felt nothing (this is with all 4 plugs out). Can it have absolutely no compression at all and still suck fuel into 1 and 2 cylinders?

Thanks

Melvin

Also,why would it blow fuel back out of the carb if there's no compression

I have been looking through you earlier posts and noticed you made adjustments to the tappets (forgive me if I read this wrong!).
Right... Lets start here! If we presume the hydraulic tappets are empty and you have done up the tappets to just touching plus one turn, it is possible this is lifting the valve slightly open and allowing air to flow past. Try loosening the tappet adjustments so they are only just touching again and see what happens.
Fingers crossed this may make some difference.

Ps. Since taking out all 4 spark plugs, have you noticed a change in cranking speed when turning over by starter motor? The speed should have increased and remain at a constant speed rather than speeding up and down slightly on each compression stroke.