Carb Mounting Studs

[Kevin (Mr T)]

I've put this on The Start Line because it hardly qualifies as technical!

 

Having had the carbs on and off recently, it's pretty clear that the studs on the inlet manifold are too long. As you wind the nuts off the lower ones end up fouling on the carb body and you have to pull the carbs away to finish removing the nuts.

 

Simple (if you know what you are talking about) question is, can these be cut down and if so, can you do it in situ? Alternatively, should I just leave well alone, on the basis that I shouldn't need remove them that often.

 

I wouldn't even be asking, but I have just ordered a brand new pair of 40DCOE151's to replace the old 112's on the car at the moment, so will be taking them off again soon

[Captain Colonial]

Unless it's fouling something that affects normal operation, my advice is leave well enough alone. Better that than too short!

[Lyonspride]

Too long on mine as well, I was tempted to shorten them on my bench grinder, but it's so rare they ever need to come off, that I didn't see the point.

[BillyPee]

I fitted new studs a couple of years ago when I serviced the carbs. Yes, they are a bit of a pain because of the fouling on the carb body. I'm not sure that they are actually too long though as IIRC there is not a great deal of thread showing out of the end of the nut once its tightened up. I'd leave well alone as its a fiddly job to get the nut on the studs and I always find that its harder to get a nut on a thread that has been shortened.

 

Did you have a specific problem with the carb bodies in order to go for a brand new pair?

[Kevin (Mr T)]

I fitted new studs a couple of years ago when I serviced the carbs. Yes, they are a bit of a pain because of the fouling on the carb body. I'm not sure that they are actually too long though as IIRC there is not a great deal of thread showing out of the end of the nut once its tightened up. I'd leave well alone as its a fiddly job to get the nut on the studs and I always find that its harder to get a nut on a thread that has been shortened.

 

Did you have a specific problem with the carb bodies in order to go for a brand new pair?

Because I couldn't get it to run perfectly, I ended up going to ATSpeed Racing, a local rolling road/Weber specialist.

 

Although he made a really good job of balancing the carbs and it did make a difference to the running, he was on the phone to Weber to try and sort out the idle jetting. No matter how big a jet he tried (I think he ended up with a 70 in as I recall), it was still running lean. His "Guru" at Weber identified the carbs as being made specifically for Alfa Romeo and apparently these have large progression holes, which causes this issue at idle and low revs.

 

He said these would be fine for racing, because of how hard you rev and, interestingly, it was originally built as a sprint car.

 

Bottom line, he could fudge it to make it OK, but was almost embarrassed that he couldn't do a proper job for me.

 

He said ideally I would fit a new pair of 151s and get them jetted so, with one birthday present outstanding, I negotiated with Mrs T that instead of a nice watch to remind me that I have turned 60, I would order a nice shiny pair or carbs to make me feel 20! 

[BillyPee]

Seems like you are a master negotiator. 

 

I'll be interested to see how this works for you. I have often considered getting brand new carbs to see if that will make the engine run that bit better.

[Kevin (Mr T)]

Seems like you are a master negotiator. 

 

I'll be interested to see how this works for you. I have often considered getting brand new carbs to see if that will make the engine run that bit better.

I'll keep you posted!

[garytipping]

Belated Happy Birthday Kevin, sound like a great present!

 

Gary

[Kevin (Mr T)]

Belated Happy Birthday Kevin, sound like a great present!

Gary

Thanks Gary