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trevinoz
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'58 Sq 4 Cylinder head removal
#803221 03/28/20 11:01 pm
Joined: May 2009
Posts: 348
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Britbike forum member
Joined: May 2009
Posts: 348
Decided to disassemble my 1958 Square Four as it has not run in several years and have read enough disaster stories about engine blow-ups because of sludge in the crank oil pathways. The only handbook (owner's manual) is particularly unhelpful so thought I'd ask the experts since this is my first attempt at working on a Sq 4 engine.
The book shows a diagram containing 18 head bolts and suggests a tightening (thus, I assume, the reverse for loosening) sequence, but my head appears to have only 10 bolts visible on top and 4 nuts on studs underneath the head. I know there have been various iterations of the heads over the years and wonder whether mine is different or am I just blind? Also, the bolts that hold in the rocker spindles - do they go deep into the barrel and therefore must be removed to lift the head or can they be left in place as they come out with the head?
Hopefully, these questions are not too stupid and someone can help - I'd rather be safe than sorry.
Thanks in advance,
Paul.


Paul

'74 Commando - Interstate
"74 Commando - Hi-Rider, possibly
'65 Atlas, mostly anyway
'15 R1200 GS Adv
'51 Vincent Rapide
'58 Ariel Square Four
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Re: '58 Sq 4 Cylinder head removal
Paul Sammut #803313 03/29/20 7:47 pm
Joined: Feb 2014
Posts: 660
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Posts: 660
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Hi
There are a couple of videos on the net showing Sq4 engine dismantling such as
https://www.youtube.com/watch?v=QwC9a2DPMiw
That was just the first one I saw, so search

John

Re: '58 Sq 4 Cylinder head removal
Paul Sammut #803345 03/29/20 11:00 pm
Joined: May 2009
Posts: 348
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Joined: May 2009
Posts: 348
Thank you John - I've looked hard but did not find anything. The chap that made those videos didn't include a video of the head removal, unfortunately, as he "didn't know what he was doing". There are no others - at least according my friend, Google.

As it happens, it doesn't matter as I figured it out and feel a bit silly - all I had to do was remove the rockers and that included the extra 4 head bolts I was looking for.

Also, thank goodness I'd decided to disassemble the engine as I was headed for disaster - as I removed the push-rods, I noticed that numbers 5 & 6 (my numbering system, counting from right across to left) were deeply gouged. In the push-rod tunnel there was a broken tappet bolt and nut sitting on top of the cam followers! I checked all the valve adjusters and all 8 are intact. The broken part must've fallen in at the time of a previous build and not been noticed by the p.o. or whomever the builder was. I hate to think of the swarf circulating in my oil and I will inspect the entire engine very carefully.

Cheers all,

Paul


Paul

'74 Commando - Interstate
"74 Commando - Hi-Rider, possibly
'65 Atlas, mostly anyway
'15 R1200 GS Adv
'51 Vincent Rapide
'58 Ariel Square Four

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