Hi. I'm trying to get a single carb cylinder head for my 1968 A65 engine project. I've seen a head in good condition but I'm unsure if it will work on my 1968 engine. The head is part number 68-714. I believe that there were changes in bolt diameter at some time but what else changed? Any views and advice regarding the suitability of the 68-714 head for my engine gratefully accepted.
Regards
Tony
I belive the early heads had 5/16 bolts later ones were 3/8. When I changed my friends cylinder head from twin carb to single I just ran a drill down the holes to enlarge for clearance for the larger bolts.
The later rocker box ie the finned on will not fit the earlier heads as they are wider. So if using an earlier head you will need the earlier s.ooth rocker box.
Thanks guys. Anyone got any views regarding whether I can use a 68-714 head on a 1968 engine please?
Regards
Tony
:) :) :) :)
I suggest that you check what the stud arrangement is on you barrells. The early models had 8 x3/8" studs and 2 x5/16th (Plus of course the short stud down in the pushrod well). Later were all 3/8". BSA produced a service sheet to modify the old barrells and heads. There are still some unmodded around. If you find a head with the 5/16th holes just drill them through or have them machined.However there was also a change to the valves at a later stage but I cant remember the detail. That is not a problem providing you use valves to fit the head.
I have fitted a very old head to a newer engine with no apparent problem, except as above.,
I hope all works out, it usually does.
Mike 8) 8) 8)
Thanks Mike. That 68-714 head might be worth a gamble then.
Regards
Tony
Quote from: idie on 14 Sep, 2023, 10:51
The later rocker box ie the finned on will not fit the earlier heads as they are wider. So if using an earlier head you will need the earlier s.ooth rocker box.
This is not strictly true. Finned rocker boxes came out in 67 and Continued to fit all pre oif cylinder heads regress of if they had a finned cover previously or not. The OIF heads with the finned rocker boxes have the 5/16 outer studs and yes they are further out.
68-714 should fit without modification.
Thanks Allan. All good info!
Regards
Tony
Hi Tony, have you bought this head yet? I've just seen one advertised as A65 and after seeing the photos noticed it's for an A50.
You want 68-881
:) :) :)
Further to post about A50/A65----- the manifolds are also different and its my experience that A65 manifolds are becoming incrasingly difficult to obtain. Just a thought.
Mike 8) 8) 8) 8)
Hi Allan. I bought my head via eBay, from Twowheelspares. It has the inlet rockers in place, all the valves and an A50 manifold on it but I've managed to find an A65 manifold in Holland. Hopefully that's not the A50 head that you spotted and referred to in your last post. Hopefully my 68-714 head, once fitted with the A65 manifold will work with A65 barrels.
Regards
Tony
I've just measured the combustion chamber diameter of my 68-714 head and it's 66mm - according to my Haynes manual that means it's for an A50 (unless anyone knows different) - what a pain! The weird thing is I can't find any details anywhere on the internet regarding a 68-714 head - it's as if it doesn't exist - but I know it does as I've got one! It looks like that head will have to go back to the supplier.
Thanks for everyone's help.
Regards
Tony
Hi Tony,
I've got a late sixties A65 Head available if you want. Email me for the details editor@bsaownersclub.co.uk
Chris