Air-cooled CU engine oil leak / low compression

[ben50]

Hi,

I put it in for a compression test as I was having difficulty starting it, especially after a week or two standing on the drive. It was making sucking/vacuum noises and popping a bit then conking out. Once started and up to temperature it seems to run fine until a long uphill, but that's to be expected with an old engine i guess.

The garage has completed the compression test and as it was low and inconsistent across the cylinders, (90 120 60 70) they have reset the hydraulic tappets, garage said I'd set them incorrectly after replacing the pushrod tubes in February (although I'd followed what I thought was the correct way to do this). Then they ran the engine for 15 mins and re-did the compression test. It was a bit better this time(100 120 90 95), and they have suggested that it may improve once I've taken it on a few long runs.

I drove from Bristol to Woolacombe and back a couple of weeks ago and all seemed to be going well, still struggling up hills, but able to keep up with most of the motorway traffic. On the return journey though, we stopped at the services half way home and there was steam/smoke rising from the exhaust, on closer inspection once it had cooled down there seemed to be oil dripping on to the exhaust, at first I thought it was just coming from the dipstick as this never seems to stay in place, but I've just been out and started the engine to check it over and there is also oil emerging from above the alternator see video below.

Are these thing likely to be connected? Is it a further indication of money needed? The garage said that if the compression/starting didn't improve that I'd probably need the engine rebuilding, which would be approx 18 hrs labor plus parts (£1500?). I was thinking that's a lot to pay out and that maybe with not too much more I should look at going subaru, gti or tdi to get more power for my money.

https://goo.gl/photos/ftVFcxiGH7eTe6hW8" onclick="window.open(this.href);return false;

If it makes a difference the engine is currently running twin 40 dellorto's and an electric fuel pump,

Cheers in advance, Ben

[bigherb]

The oil leak is possibly the rear crankshaft seal behind the fan leaking and the oil being flung around by the fan. Not really going to cause low compression more as a result of leaking compression pressurising the crankcase.

[ben50]

Thanks for the reply, bigherb.
So I guess either way the engine is going to have to come out, but hopefully not immediately?