New head gasket for a mark ii square four

[simon.holyfield]

Motors that sit for a while, often even small amounts of sludge become detached and move through the oilways I wouldn't risk running it no matter what oil. Nev

Seconded. My #3 big end was in a far worse state than the others, and the sludge was on the point of blocking the tiny 3/32" port to the journal - the others were fine.

I wouldn't risk it, from what I've seen.

[paul.jameson]

A few trips, not exceeding 10 miles, sounds a good way of finding out just how much sludge there is in No 3 sludge trap. Talk to Bruce Longman's predecessor as Square Four spares organiser, David Jones, on 01526 832858. His square threw No 3 rod on just such a trip.

You may be lucky and get away with it. If you are unlucky, I would expect you to suffer in terms of availability of those spare parts in the back of people's sheds on account of your lack of caution.

[graham.wade]

I was pleased I took this advice, my square had been standing unused for years and fortunately I made no attempt to start it. The photo shows one of the sludge traps, the gunge had completely blocked the oil feed to the big end journal.

Regards
Graham

[Paul_Linden]

Gentlemen, you're scaring me! I might have nightmares now about blocked oilways!
Seriously, i'll take your good advice and strip the engine before running her again.

Graham - just out of interest, how many miles were on the clock when you took that picture?

[graham.wade]

Hello Paul,
Only 3,500 but I'm sure it has done far more than that. I don't know the history of the bike, but the bores are on standard, the oil in the tank was clean and everything generally looked good - until the sludge traps were removed.
Good luck with it, sounds like you have found a good bike.
Best regards
Graham

[simon.holyfield]

I was pleased I took this advice, my square had been standing unused for years and fortunately I made no attempt to start it. The photo shows one of the sludge traps, the gunge had completely blocked the oil feed to the big end journal.

Regards
Graham

Thats very similar to what I found. Which big end is that?

[graham.wade]

Hello Simes,
That is front left which I thought was No.4, furthest away from the pump. Previous posts suggests this is No.3.
They all had a considerable build up, but this one was the worst.
Regards
Graham

[Bob.Murphy]

Gentlemen, you're scaring me! I might have nightmares now about blocked oilways!

And you'd be right to be scared .

When I had my 'Square' I cleaned everything thoroughly during the two-year restoration (including re-sleeving the bores, new shells and so on). The sludge traps were full when I stripped it down. When completed it was shiny inside.

I then changed the oil every 1,000 miles (Castrol GP straight 50) and stripped the motor every year (around 20,000 miles per year) and although the insides were still shiny there was always some sludge in the traps.

I didn't have a separate oil filter (in 1970) so adding one may make a difference, but if I had another Square I'd still want to strip it annually.

(I get very, very tempted whenever I see a late one for sale and the 'Ex Bob Brassington' one almost had me reaching for the 'phone . . . One day I won't be able to resist any longer ).

Bob.

[Paul_Linden]

Thanks Bob, it's the first hand experience such as yours that convinced me of the way to go (strip and clean). Cheers!
Paul