And you're probably sick of them. But for everyone who has an SU alloy manifold, I'd love it if you went out to yours and checked out the part numbers on them. I got another one in the back of my wagon when I got it, and I'm trying to figure out the differences that John Parker mention. John, do you happen to have any part numbers that I can look at?

Anyway, the two manifolds that I have appear to be the same from the exterior. Their main part numbers are both 418404, but on the other side of the manifold, my current installed one says JM 2, and the one from the back of my wagon says JM 3.

Anyone have any clue what the numbers are/mean? Were all the alloy volvo SU manifolds the same part number but with differing JM whatever numbers for different versions?

Pictures are HERE with the caption below stating which manifold the pictures are of.

In any case... The JM 3 one has longer studs for the carbs which would allow me to run my phenolic spacers... But the question is, should I? I need to find some gaskets...
--
Kyle - '68 142? - Oregon Volvo Tuners?

My guess is that the JM numbers refer to some admin detail, like YOM, Lot#,
or maybe even position in a multicavity mold. Measure the bores and if they
are the same the manifolds are the same. Unless modified, I'll bet they are
all the same (at least the ones with the same p/n).
--
George Downs Bartlesville, Heart of the USA!

I've got two here today. One says VOLVO418404 and has no other markings. It does not have a port for a vacuum fitting in the center, and it has short studs. The other says 418404 JM2 and it does have the fitting, also with short studs. No other apparent differences.

I've never run phenolic spacers and I've never had a fuel vapor problem as long as the correct heat shield was installed. I don't suppose they can hurt anything.

Rhys has lotsa gaskets.

The only differences I've ever noticed are vaccuum outlets. The studs to which the carbs bolt are replaceable. Any good hardware store should have longer ones that would allow for the spacers. I always have used the spacers, and still have had fuel vapor troubles. I've even doubled the spacers up and used two heat shields and had problems...

Gaskets should be easy to find. Or make 'em out of a cereal box and rtv blue.

-Matt
--
-Matt I ♥ my ♂

I shoulda said I never had problems with SUs that were not worn out. Leaky throttle shafts mean you gotta tune them rich at idle, and I have had hard hot starts in that condition. I don't think installing spacers is the smart fix, tho...

Phil S.=Leaky throttle shafts mean you gotta tune them rich at idle, and I have had hard hot starts in that condition.

When I put on my DGV, that's the exact condition my SU's were in. Would not restart hot unless you waited at least a 1/2 hour. Unless you had a can of starter fluid....

Andrew, do you have a alloy SU manifold? What are the numbers on it?
--
Kyle - '68 142? - Oregon Volvo Tuners?

The one I have here in Australia is part # 418404 and JM3. As far as I know it came off a 122S year unknown although on the 1966 model I had had a similar manifold.
TimC

The one that flows best is identical to that one, on the outside,
and has no part #. The difference is the shape right after the face where the
carb bolts on.

John
V-Performance.com

Interesting that it has no part number... How many of these have you come accross? The shape right after the face where you mount the carb you say? Well, can one of these manifolds be modified a bit to match one of these other ones you speak of?

FWIW, I was reading the Intake Manifold Theory found at www.grapeaperacing.com, and from looking at my manifolds, I came up with some thoughts...


This edge right inside the opening does not match the flow of the middle of the manifold right after that opening. I'm thinking of porting(or rather, blending/radiusing) the manifold here in this area to get rid of the sharp ridge, and just have a smooth opening that is all blended into one shape that flows along with the manifolds inner walls. This current shape that shoots the carb's air/fuel mix over a sharp edge and then allows it to follow the walls of the manifold doesn't seem optimal to me. I also want to clean it up a bit on the other side of the manifold where it leads into the head because it's sort of the same situation, although much less extreme and reversed. Blending in the runners in these two areas for smooth flow(I don't mean polishing anything) would be a good thing, no?

Or is that bit that doesn't match the rest of the manifold there for a reason?

John(and everyone else), why do people usually put on spacers in between the carbs and the manifold? It effectively increases the runner length, and increases the volume in between the carbs and the intake valves. Does the increased volume between the carbs and intake valves improve high RPM running? I think I was getting that impression from what I had time to read from that article... All of your thoughts?
--
Kyle - '68 142? - Oregon Volvo Tuners?