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SU Carb rebuild

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M

MichiganTed

Senior Member
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Rebuilding my SU carbs and I found:
- a ball bearing blocking the short 5/16" rubber balance tube that's between the body of the two carbs
- homemade gaskets between the damper piston housing and the body of the carbs

It's obvious these carbs have been worked on before. Any thoughts about the ball bearing? I mean what was someone trying to do here? And since the kit didn't come with the damper housing gasket (part breakdowns don't show it either) I have no plans on putting one back in.
 
It sounds like you have late model carbs on an early engine. The early carbs didn't have those tubes, so the ball bearing may have been a convenient means of blocking off the tubes.
 
I still trying to determine what kind of Frankenstein I have,
- 65 AH Sprite should be a 1098 motor
- but the tag on the block is 9C-U-H (orange paint) which is a 948
- the head is painted green, 1098??
- AUD 404 tag on the carb which is 1275
- and in the trunk (I should say boot) is a cam in a Perfect Circle box #229-1755 with empty engine gasket boxes.

Any help to sort this out would be much appreciated,
 
As far as I know, the MkII did also come with the 948. A common performance option is the 1098 head (marked inside the valve cover as 12G295) and that head worked well with the HS2 carbs, but I thought it was only the MkI Sprite that came with the H1 carbs. The AUD404 is really the same as those that came with the 1098.

I don't think that cam was for the Sprite engine.

Personally I went with the HS4s

DualHS4Carbs.jpg
 
The 948 came with the Sprite MkII but everything went to 1098 in about Nov ''63 or so. By '65 they all (originally) had 1098's.
Ted- the green color of the head is just paint. The only way to tell what head that you have is to lift the rocker cover and look at the number.
As Trev said it sounds like those are late model 1275 carbs which are perfectly good and will make your car do just fine.
As far as I have ever heard the dashpots have no gaskets. If you want the car to leak a little less you could hook the 5/16" tubes to an engine breather and simulate a PCV system. Won't hurt anything and will save you some oil.
BillM
 
Thanks for the carb pic. And I agree, that cam box is likely just a box. Great idea to use those tubes for a breather,
 
65 came with the 10CC engine (1098 big crank 59HP). When these engines are overhauled the tag is almost always removed and seldom refitted so I am betting you have a 948 engine. Head is apparently not original. Unless the power output is satisfactory I think I would be shopping for a good 1275. Before doing so though check the left front side of the block. There should be the engine size cast in the block.

Kurt.
 
On the block:
Left front is "MOWOG" and below that is "14" in small numbers
Left center is a great big "950" and below that "243" in smaller numbers,
Left rear is "2A" and below that "799"

I'm reading the big "950" as the engine size, bummer,
 
I'm sure the engine will do the well. I have no plans to race her. It's just that when you find you've the got the wrong motor I'd prefer to error larger. But I'll know soon enough. Carb's are ready, compression and oil pressure is good, spin on filter installed, new coolant hoses, vacuum advance isn't working but she sparks and I have the mechanical advance working - good enough for a test run!

Thanks everyone,
 
I own a '73 Spridget that I bought just for the 1275 engine (to rebuild and put in my racer).

But the '73 is too nice to scrap, so I'm putting a spare (rebuilt) 948 in it.
I had a box-Sprite with a 948 in it many years ago and it was a lot of fun.
They are decent little engines and give amazing gas mileage.

If you think you can't have fun with a 948, ~Here Is A Video~ of my racer sporting a stock, low-compression 948 engine (35 HP).
It was the only assembled, running engine I had at the time so I threw it in and ran this event.
 
So looks like you still had fun,but lots of looks behind you all through the race for over taking traffic.
 
Unless the power output is satisfactory I think I would be shopping for a good 1275. Before doing so though check the left front side of the block. There should be the engine size cast in the block.

Kurt. [/quote]

Did'nt mean to be hard on 948's. They are great engines but I'm afraid I think like most of the population and always feel the need for more power. That kind of thinking is probably why we can't buy a car in this country that gets as good of gas mileage as we could a couple of decade's ago. As mentioned the 948 is capable of great gas mileage.

Kurt.
 
Nice video, thanks for sharing - maybe I will run that 948 around a track!

Kurt your right - never heard anyone complain they have to much engine power.
 
Jim_Gruber said:
So looks like you still had fun,but lots of looks behind you all through the race for over taking traffic.
Click to expand...

There were 'Vettes, E-Types, Mustangs etc in that race, so even with a good 1275, I'd be watching the mirror all the time. :laugh:

By the way, that was a handicap race (slower cars start first....most laps after an hour wins).

As a result, I won!
grin.gif
 
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