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Compression readings Z1B......
Moderators: chrisu, paul doran, Taffus, KeithZ1R
Compression readings Z1B......
Hi all,Can anyone let me know the correct compression rating i should be getting when engine is cold on my Z1B? i have seen various values stated from 100 psi (service limit) to 150 psi....Cheers Pauljac...
PAULJAC47,,,,,"She may not look like much, but she's got it where it counts, kid."
-Han Solo
You can't polish a turd, but you can roll it in glitter
Salad is what real food eats.
Anon
PUM 673
-Han Solo
You can't polish a turd, but you can roll it in glitter
Salad is what real food eats.
Anon
PUM 673
Ok........ before anyone slags me off for trying to help - I have read that .....
You should check compression of a warm engine
The range is wide to take in many variances (engine build tolerances, carbon build up, some ring wear/leak, etc).
Depending what you get, will give some indication on engine wear....
If its getting toward the lower end, you can then retest with a bit of oil down the bores.... If the comp goes up its most likely ring/bore wear. if it remains the same, could be valve wear
Also, there shouldn't be more than 10% difference between each cylinder
You should check compression of a warm engine
The range is wide to take in many variances (engine build tolerances, carbon build up, some ring wear/leak, etc).
Depending what you get, will give some indication on engine wear....
If its getting toward the lower end, you can then retest with a bit of oil down the bores.... If the comp goes up its most likely ring/bore wear. if it remains the same, could be valve wear
Also, there shouldn't be more than 10% difference between each cylinder
And on the 7th day... Zeds were created!
Just curious, now i have rebuilt top end before was running fine just smokey on start up...was getting 125 psi when warm on three pots slightly less on one.yet my a4 gives 150 psi on all four!!!.By the bye you dont have a decent colour coded circuit diagram for a z1b by any chance? or a description of the operation of the brake outage relay and the brake circuit wiring?? Cheers Paul J..
PAULJAC47,,,,,"She may not look like much, but she's got it where it counts, kid."
-Han Solo
You can't polish a turd, but you can roll it in glitter
Salad is what real food eats.
Anon
PUM 673
-Han Solo
You can't polish a turd, but you can roll it in glitter
Salad is what real food eats.
Anon
PUM 673
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DogsbolloxofZ1B
- Hardcore
- Posts: 1440
- Joined: 28th Feb 2006
- Location: Near Chichester
Have I read this correctly, it seems to me that your getting less psi now than pre head rebuild! Did you have the valves re-faced & seats cut or just lap the valves with grinding paste? If the latter I'd say you've got a valve or two letting by. As said before squirt a small amount of oil in the bores & retest on a warm engine with throttle wide open. If the readings stay the same you need to inspect the head again. Valve clearances all OK?
Mike
Mike
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