Author Topic: stripped head bolts  (Read 3009 times)

Offline coater87

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stripped head bolts
« on: 26.04. 2009 14:07 »
 Hi,

 Looking at the head bolt holes on my barrels, someone at one time jammed some odd thread down the hole and made a mash of them- completely gone.

 I am not sure a heli-coil repair would hold here. First, can these be fixed properly or am I best off looking for new cylinders? This is a real shame as they are at standard bore.

 Lee
Central Wisconsin in the U.S.

Offline a101960

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Re: stripped head bolts
« Reply #1 on: 26.04. 2009 14:26 »
I had a couple of questionable threads on my cylinders. I had helicoil inserts fitted by a local engineering shop and so far they have held (8 years) and I have had the head off 2 or 3 times in that period with no discernible problems.

Offline bsa-bill

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Re: stripped head bolts
« Reply #2 on: 26.04. 2009 14:52 »
Most common helicoil repair used to be the sparkplug hole on alloy heads, if it holds there ( and they do  ) should be ok on a couple of head bolts

All the best - Bill
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline coater87

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Re: stripped head bolts
« Reply #3 on: 26.04. 2009 15:52 »
 Guys,

 This isnt just one or two, its ALL of them. I have no idea how or why these guys did stuff like this...

 Do you still think the heli's will work?

 Thanks,
Lee
Central Wisconsin in the U.S.

Offline a10gf

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Re: stripped head bolts
« Reply #4 on: 26.04. 2009 16:03 »
Quote
why these guys did stuff like this
Maybe had a leaky gasket, tightened up everything extra+++ tight, one thread went bust, then retightened the others to compensate, then...

Since it's in good shape otherwiswe, it's very worth salvaging, bring it to a renowned machine workshop, good chances they will have the solution.

e

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Offline Dynamo Regulators Mike

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Re: stripped head bolts
« Reply #5 on: 26.04. 2009 17:26 »
Lee

Just fitted Helicoil type inserts to my barrels. Made sure they were 2 x diameter inserts to suit the length of bolt thresd in hole. Jobs a good 'un. Manufacturers claim repaired thread is stronger than original and I have no reason to doubt it.

Mike
Mike Hutchings
A10, B50, T800; 1,2,3 (& DVR2)
Director, DRL www.dynamoregulators.com

Offline bsa-bill

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Re: stripped head bolts
« Reply #6 on: 26.04. 2009 17:45 »
Sorry Lee did not spot it was all the bolts, would think it would be alright though, if your in doubt take it to a shop and ask, there are other insert available.

All the best - Bill
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online A10Boy

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Re: stripped head bolts
« Reply #7 on: 26.04. 2009 18:22 »
Lee,

I'm with manormike on this, a helicoil fitted properly is as good as the original thread.

In the absence of head bolt torque settings, some people will get their longest bar and hang onto it with gritted teeth. Obvious this isn't necessary.

You don't say whether you have a cast iron or alloy head. Personally, [and I know people might disagree with this], if its an alloy head I would use a composite gasket and torque to about 32 ft/lbs. If its a cast head I would use a solid copper gasket and torque it to 36 ft/lbs. either way, your helicoils will be fine.
Regards

Andy

1960 A10 - Black Golden Flash
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Offline coater87

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Re: stripped head bolts
« Reply #8 on: 26.04. 2009 19:19 »
 Thanks for the help guys,

 I am just looking over the pile of bits I have, and this looks like it will be a common problem. The kids who tore this down to chopper it used an awful lot of Honda parts, including the bolts....must have been shinier!

 I am just trying to get an early idea of what needs doing here, as I have decided to crate the whole mess up and send it to Wes Scott Cycles for a sound going through.

 BTW, is there anyone on here who has a lot of A10 parts on E-Bay? I have had a look at the UK site and cannot believe the selection you guys have- sure are lucky. Over here, we have one or two good sellers, then of coarse the Taiwan stuff and the guy from Chicago.

 Oh yeah, its an iron head.

 Lee
Central Wisconsin in the U.S.

Offline BSA_54A10

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Re: stripped head bolts
« Reply #9 on: 27.04. 2009 13:52 »
Lee,
Never Never ever buy anything from the "guy in Chicago"

Go to any Brit site and ask for some one to verify the varasity of Marshal from Chicago but don't hold your breath waiting for some one to have a good word to say.
If all the threads are cactus then I would seriously consider going to the next size larger bolt
Bike Beesa
Trevor

Online RichardL

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Re: stripped head bolts
« Reply #10 on: 27.04. 2009 14:47 »
Lee,

Must agree with Trevor. Marshall has a lot of bad press and doing anything with him over the internet or other remote communications is probably a problem. I have purchased a few things from him by rummaging through his shop (I don't know if that still exists) and at swap meets. The point being, all is OK if you are standing there looking at the part you want, making your own judgements and expecting no guarantees.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online groily

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Re: stripped head bolts
« Reply #11 on: 27.04. 2009 22:00 »
I think it would be very hard to go that route unless you wanted to drill the head through to take the oversize bolts (assuming they could be got anyway with, say, 7/16th BSF shanks and the small head required to get spanner clearance on these engines). When I had one stripped thread in the barrel of mine, it was luckily on a hole that could be equipped with a stud, so I made one with a 7/16th BSF thread into the barrel and standard 3/8th diameter up top, to take a one-off deep nut. It was the rear right-hand-side hole behind the plug. The holes in the centre of the engine wouldn't, I think, allow the use of a stud and nut unless the engine were taken out to put the head on, which is taking things a bit far.
And such solutions aren't pretty, however functional! Helicoils offer a better answer, which I'd have adopted had I known they were OK for these sorts of applications at the time. It was the folk here who clarified the suitability of helicoils then; the advice is still good, and I think certainly the best option if the whole lot need sorting out.
Bill

Online trevinoz

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Re: stripped head bolts
« Reply #12 on: 27.04. 2009 22:47 »
I have used helicoils in barrels and have had no problems whatsoever.
 Trev.

Offline BSA_54A10

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Re: stripped head bolts
« Reply #13 on: 28.04. 2009 09:21 »
I have nothing against helicoils but as you still have to drill and tap every hole, using bigger bolts just deletes one step.
It is ultimately up to you, but there is always more than one way to skin the proverbial cat.
If you se inserts then try and get a set with the longer inserts as you can cut a too long insert down ( with a Dremil & cut off wheel).
The kits usually come with the short ( 1x diameter) inserts which are really only good in thin alloy.
The longer the insert the less chance of it winding out and don't forget to drive them in 1 full turn below the surface.

Bike Beesa
Trevor

Online groily

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Re: stripped head bolts
« Reply #14 on: 28.04. 2009 12:17 »
Yes, you do still have to make bigger 'oles - but will oversize BOLTS pass down through the head? And will they do up? They already have undersized heads for their shanks. That seemed to me to be the problem there. And was why I made a stepped stud in the one case I was faced with, over which the head could be lowered. Always several ways to skin the cat, absolutely, I'm all in favour. But I wouldn't want to enlarge all the holes through the cylinder head if that's what it would take. But maybe they're big enough already?
Bill