Alloy head bolts

[orabanda]

Hi All,
Can someone please supply the lengths of the bolts which make up a set for (a) a 1954 A7 SS, and (b) a 1958 A10 Super Rocket?

Should all or some of the bolts be of a "waisted" type?

Thanks,

Rickity Dick

[muskrat]

G'day mate, the SS and the SR are the same length, the longer 6 are wasted. Sorry can't help with measurements right now.

[wilko]

I wouldn't recommend alloy bolts as they will keep stretching each time you re-torque. Steel is better.

[Rocket Racer]

I wouldn't recommend alloy bolts as they will keep stretching each time you re-torque. Steel is better.

brilliant 

[RichardL]

Richard,

I assume you have no question about the part numbers. It seems that Burton Bike Bits http://burtonbikebits.net  lists bolt sizes on their price list. My A7 and A10 are both apart right now, so I will try to get measurements off of the actual bolts this evening.

Richard L.

[trevinoz]

Richard, (Rickity)

Head bolts are:-     Long, waisted - 3", original bolt- 13/16" thread, pattern- 1" thread.
                           Medium, waisted, 2-5/8', original- 7/8" thread, pattern- 1" thread.
                           Short, plain shank, 1-5/8", original- 11/16" thread, pattern- 1-1/16" thread.

We shall see if Richard L's measurements are the same.

I suppose it's a matter of time before they call you "wrinkly".

Trev.

[RichardL]

Better than "shriveled".

[orabanda]

Trev,
As long as they don't call me late for lunch!

You are a gentleman and a scholar, but just a tad too cheeky; a typical Eastern sider

As for you, manosound: - Thanks as well!

Richard

[RichardL]

Richard,

Here are the dimensions of my head bolts shown in the photos. I didn't follow good engineering practice because the number of decimal places isn't consistent, but I think you will get past that. Obviously, I didn't round to nominal dimensions (like, in 1/16 ths of an inch), but just entered the caliper readings for the one bolt measured of each type. The A10 bolts should be correct stock or replacements. I think the bolts from the A7 are stock or correct replacements also, but I really don't know yet, not having gotten too much into it since purchase in November. Also included is a picture of the head of one of the A7 bolts where "Wiley R" is formed. I would be interested to know if anyone is aware if this signifies an original part.

Richard L.

P.S. The drawing is something of a mess because of using the A10 seat as a photo table. Sorry about that.

[trevinoz]

Richard L.
                  Wiley bolts were original fit. Quite a few heads about the bike were so marked.

Trev.

[bikerboy]

I have found this useful in the past

http://stainlessbits.com/link12.html

You look for the part number of the bolt/nut and it gives you the spec

[beezermacc]

I find that the head bolts supplied by the likes of MCA and Wassell are too short. If you measure the depth of the aluminium plus the depth of the threads and add about 2mm for the thick washer you'll find that the bolts supplied are about 8-10mm too short. I've come across a few people stripping threads recently. I have obtained some high tensile socket cap bolts which I have cut to the correct length to ensure using all the available thread in the barrels.

[bsa-bill]

correct length to ensure using all the available thread in the barrels.

I think this is maybe not so good, how do you know if your clamping or bottoming
(plus if my last project is any guide there needs to be room in there for POs accumulated crud, not that anyone here would allow that to happen)

[Briz]

I find that the head bolts supplied by the likes of MCA and Wassell are too short. If you measure the depth of the aluminium plus the depth of the threads and add about 2mm for the thick washer you'll find that the bolts supplied are about 8-10mm too short. I've come across a few people stripping threads recently. I have obtained some high tensile socket cap bolts which I have cut to the correct length to ensure using all the available thread in the barrels.

Yes, I've found this. Especially the shortest bolts. Inadequate thread engagement.
The way to avoid bottoming out is to test & measure.
I too used top use quality allen bolts, but harder to find now in BSF threads.

[beezermacc]

correct length to ensure using all the available thread in the barrels.

I think this is maybe not so good, how do you know if your clamping or bottoming
(plus if my last project is any guide there needs to be room in there for POs accumulated crud, not that anyone here would allow that to happen)

I run the bolts down into the barrels without fitting the head, measure the free length under the socket cap and compare this with the depth of aluminium of the cylinder head. Obviously it is necessary to do this sort of check when using non-standard parts, but better than using the commercially supplied stuff which is too short and leads to stripped threads.