Page 1 of 1

803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 12:27 pm
by rogerowen
In my bid to replace an 803 with a 948, I learn that the carburettor is a different size - although the manifold on each appears to be the same (photo of 803). Should I be looking to find an HS2 and manifold from a 1098? or will I be able to fit an HS2 onto this older type of manifold?[frame]Image[/frame]

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 3:47 pm
by mike.perry
The 803 carb is an H1 11/8in, the 948 carb is an H2 or HS2 11/4in. I think that the mounting stud spacings are different. You would be much better getting a 1098 manifold.

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 3:51 pm
by brucek
The carb-inlet manifold shape is also different on the 948/1098. The 948/1098 is diamond shaped with rounded ends, the 803 is as you see in the photo a bit squarer. There are plenty of later manifolds around so finding one shouldn't be a problem.

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 4:35 pm
by rogerowen
Hmmm. Here's a picture of the manifold fitted to the 948 lump. Looks just like the 803 one to me - hence my confusion.[frame]Image[/frame]

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 4:39 pm
by bmcecosse
NO - that 948 manifold is NOT like the 803 one.. It can be used - but the later HS2 manifold is better.

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 5:26 pm
by brucek
Absolutely. It's the joint between the carb and inlet manifold that is different . Your 803 picture shows the carb and spacer block which is clearly a different shape to the carb mount on the 948 manifold in the later photo. The rest of the manifold is the same I think. By choice, the later 1098 one is a better unit, is as cheap as chips and is readily available.

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 7:02 pm
by mike.perry
If in doubt - Try it out

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 7:20 pm
by rogerowen
'Should have gone to Spec-Savers'. I think I can see what you say. Next Question.... what carb would have been fitted originally to the 948?

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 7:36 pm
by PSL184
Hs2

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 9:12 pm
by mike.perry
See my earlier reply, 1956-9 H2, 1959-62 HS2

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 9:46 pm
by rogerowen
OK, thanks!

Re: 803 vs 948 Confusion persists.

Posted: Thu Feb 09, 2012 9:56 pm
by rogerowen
Ah!, If there was a change in carburettors from H2 to HS2 on the 948, could this explain the different manifolds between early and late 948's? I have another 948 engined car (1960) and the manifold arrangement is completely different to the 948 engine I intend to replace the 803 car.[frame]Image[/frame]