So where are we, we'll I switched to a smaller pulley and seem to be make 8-9 psi which is better than 12!
My current issue are:
1. The engine seems to bind when hot, only if I stop and re-start, it's like the battery is a bit flat. Not sure if this is just normally
running in or indicates a problem?
2. Little bit of smoke from the breather, this could be because I'm running 10w40 running in oil or it's fooked
3. It sounds like a bag 'o' nails under load, I'm thinking either fooked or timing?
Looks like I'll be getting my spanners out again, compression test results on a warm engine with WOT (in PSI):
So it's a 2 cylinder ATM, which explains why it sounds like it's misfiring!
I need to work out if it's the head or the pistons. I replaced all of the piston rings (checked they were correctly aligned at 120 degrees t
each other) and the exhaust valves.
I think I'm going to take the head off, align all the pistons to the same height pour 50 ccs of oil in the and check every hour or so, unless
anyone's got any better ideas, probably do the same test on the head....
So my thinking, given the limited mileage (about 50 miles under load) I think the rings are still to properly bed in and no. 4 is probably ok. No. 2
has a slight leak on the head, and nos. 1 and 3 aren't really trying, so I'm going to get some new inlet valves whip the head off regrind
the inlets and check for sealing and see where I am at that point.
Carrying out a compression test with the cams removed will not achieve anything, if the inlet valve is closed how is it going to allow air in to be
compressed? A cylinder leakage test on the other hand will work as the air is supplied via the spark hole
So the results with the cams off:
All cam off tests were run with the cylinder starting in bottom dead centre, as the inlet valves wouldn't be opening so I needed to start with a
known amount of air to pressurise. I ran no. 3 twice to make sure it wasn't an error.
I think what this is telling me is no.1 the shims are too big preventing the valves from closing properly. No.3 is the pain as I don't know if
this is a valve seating issue or piston rings not sealing.
I've decided to send the head off to re cut the valves seats...
When i rebuilt my blacktop (had done 80k in donor car + 20k in my car), the valve guides on all the exhaust valves were worn beyond spec, i had them
replaced while the head was being ported.
I didn't have any sealing issues at the time, but have repaired quite a few vw engines where the seat wears oval due to valve guide wear
allowing the valve to wobble as it closes, you may have the same issue.
I'd thought I'd get away with not getting them cut, to be fair on 3 of them I would have but for how long?
I don't have access to an air line so trying to run a leak down test is a non starter, although if I'm still down on pressure on no.3 then
I might have to...
Had the valves re-cut and replaced the inlet valves, so now all new valves, lapped the valves and shined to spec. N0.3 Still 25 PSI. Took the piston
out and no.3 has collapsed. So what's going wrong? I should be down around 9 PSI and I've not seen a consistant max boost higher than 9,
timing should be conservative enough, see below? I'm now thinking forged pistons and I think rods too as I'm not sure you can split them