My scratch-build 88 engine was getting there, but I decided the cylinder head condition wasn't good enough to continue the project, so I bought a replacement Head (EBay) and built that one up (actually a really good buy- excellent exhaust pipe and spark plug threads, and the valve seats look as new).
When I came to final assembly, my inlet manifold doesn't fit the stud spacing, and when I measured it all up, the penny dropped, and I found I have different Heads - the 'new' one has a 1.00" bore for each inlet tract and the old one has 0.900" bore. So this head is for a 99? If so, with the right carb set up, will it be ok on an 88? The essential spigot fit at the top of the cylinder barrel matches exactly.
All comments (apart from "you muppet") greatly appreciated.
Dave Comeau's 'Atlantic…
Dave Comeau's 'Atlantic Green' website compares lots of heads. The inlet ports for 88SS and 650SS are oversize for their 1 1/16" carburettors and have sleeves inside to bring them back to size. If yours is 1" it must be earlier. Gordon has asked the key question...which way do the studs lie? Side by side, or one above the other?
- Log in to post comments
Head
Any Norton twin head with one inch port will work fine . The only difficulty will be the different port angle on the downdraught head needing SS pipes and the manifold studs layout which changed in 1959 with the introduction of the head with milled off fins between rocker fixings and again with the downdraught head , I fitted 650 SS carbs to my 88 std motor with no issues at all . I don’t think they made 650 heads with 1” ports . You just need the right manifold for your head.
- Log in to post comments
Headaches with Heads
Hi Russ.........some photos of your 2 cylinder heads would help with your ID crisis.
As a rule, from around 1956 onwards, the 77, 88 and 99 models all used the same cylinder heads and carbs up until the SS variations arrived. Most with a 1" bore for the manifold. The manifold having 1.5" vertical stud spacings.
Up until 1959, these heads had a casting number on the top........probably T2225. After 1959 the casting number became 22707. But this head had vertical manifold spacings of 1 5/8". Plus just to add to the confusion, the first 650SS cylinder head used the same casting number but had a different horizontal twin manifold set-up and exhaust ports that were more widely splayed.
If one of your cylinder heads has 0.90" intake bores then it is probably from a Model 7 but possibly from an early Model 88. Both available before 1956. The casting number would probably still be T2225 unless it is a pre-1952 item in which case it might show T2212. Possibly even 2140 for one of the first Model 7s built.....1949/50. But these would be made form cast iron and not Alloy unless they were Racing Heads.
See the attached photos for a few ID clues.
- Log in to post comments
Domi inlet manifold confusion
Thanks all (as ever) ......it seems my newly rebuilt cyl head is probably a 99 model, but will work ok on the 500cc engine, if I can figure out the carb jetting adjustment needed for the larger inlet tracts.
FYI my "old" head has 'T 2225' and my "new" one shows '22707Y' although these may be casting numbers rather than Norton finished part numbers.
- Log in to post comments
As far as I am aware, the 88 and 99 used the same heads. I have on occasion swapped heads between 88s and 99s without a second thought. Your manifold is a bit of a puzzle though. Perhaps someone with deeper knowledge than me can enlighten you (Phil?)
The only manifold difference I have observed is between standard and SS heads. Standard heads having vertical stud spacing and SS having horizontal stud spacing.
Pictures would help.