'58 SQ4 REBUILD

Singles, twins and fours.
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berniejones
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Re: '58 SQ4 REBUILD

Postby berniejones » Fri Apr 12, 2019 9:54 am

Yes, toolbox looks right to me but modified to carry instruments that could only be seen if your head was in the back of your knee!
If you can't get another one then a GRP repair using 'woven roving' sheet on the back and epoxy resin will work well, then fill the front and sand flush.

When you say the oil pump is OK I'm a bit sceptical if it's the original.... I replaced mine ('56 rusty dismantled basket case) with a Morgo pump as part of the rebuild. The BSA-style geared pumps never over impressed me even on the singles and twins but on the SQ4, with double the bottom end to lubricate and the top end coming from the feed side I just didn't want to risk all the time and cost of the rebuild with the original style pump. Might be worth getting the thoughts of others on that topic. Also, I think that the increased flow rate to the top end helps to keep the camshaft lobes better lubricated as the oil drains back down helping to reduce wear.

I still have a box of bits from my rebuild - mainly engine and clutch parts and a few chrome nuts and bolts. Let me know if you have a list of bits that I might be able to help with.

Enjoy your project - I suspect it won't be a quick one!

Cheers,
Bernie
'56 SQ4
'52 BSA M21
'61 Dommie 99
'81 T140
'54 Sunbeam S8
AOMCC# 4631

KenGriggs
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Re: '58 SQ4 REBUILD

Postby KenGriggs » Fri Apr 12, 2019 4:44 pm

john.bebb wrote:Hi Stewart - if you're not against sane upgrades; - strongly suggest an Iron Horse alternator - 12v 300W - then you can see, be seen & fit heated grips, an en suite closet & whatever takes your fancy... recommend you do NOT use cheaper alternatives to the Iron Horse device...
Have Kirby Rowbotham do your distributor & fit Boyer Bransden ignition...
As for brakes - if you can get hold of one... the Grimeca 9" 4LS is a superb device & requires NO mods to forks.
Cheers, John


I'll second that on the Iron Horse alternator. It's a dead easy replacement for the standard Lucas dynamo, and until you look closely you'd never know the difference. However, having a 12v system with a good alternator easily beats the standard 6v setup, and all your battery charging worries go away. Seeing as you probably haven't got a good 6v battery anyway, it's a bit of a no-brainer. You can use a modern 12v battery inside a dummy case, so it looks the same. Dummy cases are available, but I made my own as a glass fibre moulding.

roger.fellows
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Re: '58 SQ4 REBUILD

Postby roger.fellows » Fri Apr 12, 2019 7:12 pm

Drags do a 'CNC machined steel' replacement body so that your MAZAC item can be discarded if that sounds better Stewart. I don't think the original pumps were inadequate - that would probably be a common theme on here if it were the case. Having said that, I've gone for a MORGO. Whatever you use needs setting up carefully as regards the working together of the spiral gears. There have been instances of MORGOs 'blowing up' due to misalignment.

If you fit a cam spray bar, the top end may need less oil - and blow less through the valve guides. I can't 'do the maths'.


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