MK2 square- fitting cyl. head......

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bob cottam
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MK2 square- fitting cyl. head......

Postby bob cottam » Fri Mar 09, 2018 8:09 pm

Hi All, finally time to re-fit cyl head on my `58 square after extensive re-build. Never been here before so I have been doing a "dry run" so to speak in order to figure out any possible pitfalls when I do the job for real.
I have gone to great lengths to avoid any stud pulling issues with 303 stainless waisted studs, Otto gasket etc etc, and studied Bruce Longmans torque settings chart for the applicable combination of above studs /nuts/gasket.
On my dry run I note that the two centre nuts at the rear of the head, and the four central sleeve nuts cannot be tightened with a socket due either to close proximity to head casting/ presence of the oil transfer pipes in the rockerboxes- (only on a British Bike!!)- come to that- the four downwards studs from the head cannot be socket accessed either....... anyone any ideas how to torque these correctly with no socket, or it it a game of what feels right?
Bruce also suggests cutting a slot in the head gasket from each of the four central rocker block studs to the push rod tunnels- to drain any oil that may get down the stud holes from the rockerbox and prevent subsequent leaks- Anyone done this ?- what was the result?

All tips/wisdom greatly appreciated in advance, Regards, bob C

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simon.holyfield
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Re: MK2 square- fitting cyl. head......

Postby simon.holyfield » Fri Mar 09, 2018 8:44 pm

A pitfall I have come across with those nuts Bob is this.

You will have realised that they use reduced hex nuts I guess. I use a small ring spanner on these with a spring balance, but the issue is that on my head the casting is not clean around those nuts (the rear two) with the result that spanner access is even worse than usual, The casting needs cleaning up around the rear nuts to allow the spanner to get better access, a job I will do when the head is next off. I'd have a close look at the two rear nuts and make sure you can get a spanner on them and turn it.

The area I am talking about is shown in a picture in this blog post.

http://ariel-square-four.blogspot.co.uk ... -down.html

My bike is a Mk1 - ignore this if the Mk2 is not the same!
cheers

Simes

'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'78 CX500
http://ariel-square-four.blogspot.com

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robjameson
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Re: MK2 square- fitting cyl. head......

Postby robjameson » Sat Mar 10, 2018 12:03 am

I know you can buy ring attachments for torque wrenches, and you could use a crows foot, but I don’t know the access issues, so I’m unsure if that helps or not...
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Re: MK2 square- fitting cyl. head......

Postby mbovino » Fri Mar 16, 2018 9:53 pm

I've heard of a technique where the opposite end of a double-ring spanner is fitted with a bolt, two washers, and double nut so as to jam the bolt from coming loose. A torque wrench and socket can then be applied to the bolt/nut assembly to tighten the subject nut in the opposite ring. Though it sounds counterintuitive due to the increased length of the wrench assembly, those who've "calibrated" by testing both with and without the double-ring spanner claim the torque applied is accurate. I'm sure the same would work with an open-end spanner if that is required to fit in tight quarters.

I am considering fitting a new Otto head gasket on my Mark 1 due to oil leaks from I presume the pushrod tunnel. I am curious to know more about the idea of cutting slots in the gasket to let oil drain away from the central studs. Could that be the source of the leak; actually running down the studs from the rocker boxes and out of the stud bottoms? Seems a dab of gasket shellac would cure that on assembly. I can't pinpoint the leak, but it seems to be coming from an area just below where the head meets the cylinders. I would love to know what I'm aiming for before I tear into it.

bob cottam
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Re: MK2 square- fitting cyl. head......

Postby bob cottam » Sun Mar 18, 2018 8:41 pm

Hi mbovino- Bruce Longman refers to this issue in the literature he supplies with Otto gaskets. Apparently, oil leaks around the head/barrel joint can be caused (as I understand it) by oil finding its way down the sides of the 4 (large)rockerblock studs from the rockerboxes. When it gets in there, the heat cycles of the engine expanding and contracting can "pump" trapped oil past the gasket leading to weeps.The recommended solution is to cut small slots in the head gasket from the stud holes to the push rod tunnels to allow any oil to drain and prevent any pressurization, along with a little strategically applied gasket goo to the sleeve nuts/rockerblock bases etc, to stop the oil getting in there in the first place....

I overcame the problem of socket access to the sleeve nuts by cutting an old 3/8" drive socket into 3 slices with a grinder, and welded the drive square part onto a thin section of the hexagon end in a stepped figure of 8 shape,using a small piece of flat steel plate as a connector and throwing away the centre slice of the original socket. This allowed me to slip the hexagon part under the oil pipe and onto the sleeve nut, leaving the drive square sticking out to the side of the oil pipe. It gives about 90 degrees of turn before it has to be re-positioned, -worked a treat and due to its compact dimension, would have little effect on the torque figure as only about 12-14mm extra leverage Bob C.

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Re: MK2 square- fitting cyl. head......

Postby mbovino » Sun Mar 18, 2018 9:58 pm

Bob,
Thanks for the tips. That now makes perfect sense as I couldn't logically figure out the path of how oil is leaking from that area. I purchased my Otto gasket set from Draganfly and unfortunately did not get Bruce's suggestions. I tried to google his name to find out more but could only find the man, not the tips. I'm sure it's out there somewhere.

I'd love to see a photo of the tool you made. If you have a photo, kindly forward it to me at mjbovino@gmail.com.

Thanks,
Mike

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Re: MK2 square- fitting cyl. head......

Postby bob cottam » Mon Mar 19, 2018 10:00 pm

Hi Mike , here it is. Sure is ugly but works fine- I actually used a socket that was a size larger than the hex-so it would " rattle" on if space was really short, and given that I would only be tightening to low torque, it would not slip. I needn`t have worried- there was plenty of room to slip it under the oil pipe after I filed the welds to minimal...Bob
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adrie.degraaff
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Re: MK2 square- fitting cyl. head......

Postby adrie.degraaff » Tue Mar 20, 2018 5:47 am

What a beauty :D .

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Re: MK2 square- fitting cyl. head......

Postby mbovino » Mon Jul 09, 2018 7:37 pm

Very clever socket adaptation. I surely have a spare to sacrifice for the cause!


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