Compression test results?

Post Reply
BYY922
Posts: 11
Joined: Wed Jan 03, 2018 6:25 pm

Compression test results?

Post by BYY922 » Sun Apr 15, 2018 8:57 pm

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?

GOY189
Posts: 557
Joined: Sun Oct 19, 2008 5:08 pm

Re: Compression test results?

Post by GOY189 » Sat Apr 21, 2018 10:57 pm

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

User avatar
Phil - Nottingham
Posts: 357
Joined: Thu Oct 09, 2008 10:45 am
Location: Nottingham

Re: Compression test results?

Post by Phil - Nottingham » Sun Apr 22, 2018 7:23 am

I use the B5ES in our 1939 16. BPR6ES is a colder plug
P2/P4/P5/P5B/LR's - EXJ 8**/2**8MY & others

BYY922
Posts: 11
Joined: Wed Jan 03, 2018 6:25 pm

Re: Compression test results?

Post by BYY922 » Mon Apr 23, 2018 6:40 pm

Thanks chaps. Any idea if anyone would have a set of guides/ valves and ballpark price?

GOY189
Posts: 557
Joined: Sun Oct 19, 2008 5:08 pm

Re: Compression test results?

Post by GOY189 » Sun Apr 29, 2018 10:05 am

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

BYY922
Posts: 11
Joined: Wed Jan 03, 2018 6:25 pm

Re: Compression test results?

Post by BYY922 » Sun Apr 29, 2018 7:03 pm

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.

Post Reply