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A65. I removed the head to address coil binding. Upon reassembly I annealed the copper gasket before fitting the head.
I've put probably 100 or so miles on it since.
I have not re-torqued the head bolts since reassembly.
Now I'm getting a bit of oil seepage from the back of the cylinders around the push rod tunnel.

I know I should re-torque the head after a few runs. Is it reasonable to expect that tightening the rear head bolts will address the oil seepage?
Or should I take it apart and evaluate?

Thank you

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I have never had to retorque following the initial torquing procedure so your issue may come down to one or more of the following.

1) some of the bolts may be too long, test for them without the washers, if they thread all the way by hand, only being stopped by the head of the bolt against the aluminium head then they should be fine.

2) the threads in the barrel are toast, I’ve known of 2 which have failed in the area you mention. Both started off with 5/16” rears, then I took them out to 3/8”. They then were helicoiled. (Might be worth noting that all 5 of the bolt Holes in my current barrel have now been helicoiled. I never had an issue since doing this.

3) either the head or barrel surface isn’t flat. Use as thick a gasket as you like, if it’s not flat then it won’t seal, copper gaskets aren’t a wonder stuff that fills the cracks.

4) the bolts being used are just shocking, the threads are a bad fit and are of poor quality.

5) or... you need to re-address your head torquing procedure. Take them all up about 5ftlb at a time, don’t go beyond the torque limit. Then slacken each one, one bolt/nut at a time and retorque before moving onto the next one. If you put a mark on the head and the head of the fitting you will see it actually
Goes further. (This is not the same as torquing another few ftlb) the setup will have settled, and your just re-applying the correct torque to the settled part. This is on par with doing a 500mile retorque.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

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do a compression test and see if it is anything more than a cosmetic issue

test comp before and after torqueing ..........i have never bothered annealing head gaskets sometimes annealing makes them to soft so definitely re torque if you have used an annealed gasket


"There's the way it ought to be and there's the way it is" (Sgt Barnes)
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Allan, how much do you slacken after initial torquing?


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Originally Posted by Nick H
Allan, how much do you slacken after initial torquing?

I take it back enough so that it is free to turn by hand, you don’t want to take it out again.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

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What I do is use bearing blue between head and cylinder and sand high spots till there is even contact. Then I clean and fit a solid copper gasket with a smear of super sealer on each side. I torque it down adjust tappets. I use super sealer no base gasket because I don't want it compressing and having to adjust tappets.

One stock iron cylinder we had pulled a crack just under the rear bolts at the pushrod tunnel make sure where your oil leak comes from.


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Mark, I did a search on "super sealer" and got a variety of products, none of which suggested automotive use.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
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This one.

https://www.ebay.com.au/itm/302369853726

It's called three bond Supersealer it's a grey RVT silicon. It's not stringy like some. It's what is often used on Jap bikes. I've used it since putting a triple together with wellseal and having the case joints all leak because the R40 dissolved it. If you can imagine the work in that. If I put the rocker cover on with supersealer when it sets I could take the screws out. Need to tap it off.

Some of the Jap 2strokes recommend it on head gaskets rather than skimming if they are a few thou out. It seems to prevent seeps.

Last edited by Mark Parker; 11/30/20 5:24 am.

mark

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