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Compression test results?

Posted: Sun Apr 15, 2018 8:57 pm
by BYY922
I’ve just carried out a compression test on my ‘35 14. 1-5 recorded 130 psi and no.6-135 psi. Whilst they’re nice an consistent, I want to know what the bmep is supposed to be as per the factory spec?
Additionally, the plugs (Accuspark AC9CR) are oiling and sooty even though mixture and timing are correct so I suspect they may be too cold, your comments please as to good heat range/make of plug?
Im getting a big plume of smoke after idling or restarting hot so my guess is valve guides?

Re: Compression test results?

Posted: Sat Apr 21, 2018 10:57 pm
by GOY189
Can't help with bmep but the pressures achieved seem OK. The valve guides do not have seals on those engines. The Accuspark plugs cross ref to NGK B6PRES. Champion N8 or NGK B5ES usually work well, avoid the projected nose plugs (the P in B6PRES). Hope this helps
Mike

Re: Compression test results?

Posted: Sun Apr 22, 2018 7:23 am
by Phil - Nottingham
I use the B5ES in our 1939 16. BPR6ES is a colder plug

Re: Compression test results?

Posted: Mon Apr 23, 2018 6:40 pm
by BYY922
Thanks chaps. Any idea if anyone would have a set of guides/ valves and ballpark price?

Re: Compression test results?

Posted: Sun Apr 29, 2018 10:05 am
by GOY189
Meteor spares who advertise in Freewheel can probably help. Engine reconditioners may be able to knurl the guides to improve the seal, reface valves and recut valve seats that are beyond grinding.

Regards
Mike

Re: Compression test results?

Posted: Sun Apr 29, 2018 7:03 pm
by BYY922
I was always lead to believe that knurling lead to quicker wear due to the reduced surface area. I’d rather press in new ones, but appreciate the advice.