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Size of the nuts that hold the carbs on

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wkilleffer

wkilleffer

Jedi Knight
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Hi everyone,

I thought last night would be the night that I got my car running, but I ran into a bit of trouble.

Everything but the carbs is now back on. The carbs would have been back on too, except that I seem to have lost the nuts that hold them on to the studs that stick out of the manifold.

Are those nuts something I should be able to find at a hardware store or auto parts store? If so, which size and thread pitch do I need to look for?

My car's a 1974 MGB with an 18GK engine and HS4 carbs, if that makes a difference. If these are available locally, I'll have the car running and drving by the end of the day.

Thank you,
-Bill
 
Don't remember the thread size, but 5/16 x 24 sounds right. I do remember that you use a 1/2" wrench. Take the wrench to the hardware store. Remember it is fine thread.

I guarantee you will find the old nuts after you buy new ones.
 
When working on British cars, don't go by the size of the wrench! The threads could be just about anything. FOr example Whitworth. In this case, the thread sounds correct though.
 
Steve, on the later stuff it's nearly impossible to find a Whitworth fastener. A couple on the lever shocks come to mind.
Jeff
 
maynard said:
I guarantee you will find the old nuts after you buy new ones.
Click to expand...

Yeah, I'm expecting that they'll be on the garage floor the first time I back the car out. I've pretty well scoured the area, but that's where they'll be.

Thanks to everyone for the assistance. I'm off to the hardware store, or lunch first, depending on what SWMBO says.
 
Jeff - "...it's nearly impossible to find a Whitworth fastener". There are more BSF and/or BSP fasteners and plugs than one realizes on the MGBs. Below is a list of the ones I have identified.

Right Side Rear of Block
Oil Pressure Take Off Adapter - 1/4 BSP
Adapter for Oil Cooler Line/Filter Pipe - 1/2 BSP
Nut on End of Oil Cooler Line/ Filter Pipe - 1/2 BSP
Coolant Drain Plug - 1/4 BSP
Oil Pan Drain Plug - 1/4 BSP

Left Side Rear of Block
Oil Gallery Plug (Above Relief Valve Cap) - 3/8 BSP
Relief Valve Cap - 1/2 BSP

Other Items Using British Thread System
Shock Fill Cap 5/16 – 26 BSC or BSB

All carburetor fasteners are British Association sizes, mostly 2BA. A 4” adjustable Whitworth spanner works fine on all the nuts.

That said, the nuts for holding hte carburetors tothe intake manifold are 5/16 - 24 SAE.
Cheers,
 
The car's alive now. Did the carb tuning thing and took it for a spin. Seems to run nice, just sputtered a couple of times. I couldn't get the exhaust bolts all the way tight, so it probably shouldn't be in the rotation just yet. But it's running now.
 
Jeff - I suppose that we shoud refer to "British fasteners" or "Imperial fasteners" instead of Whitworth, since all of them use Whitworth or BSF heads (BSF being just the next size down Whitworth - i.e. a 3/8 BSF bolt has a 5/16 Whitworth head). The interesting thing is that even the pre war and T series cars didn't have any actual Whitworth fasteners in them (the T seres had only one), but all the fasteners, including the metric bolts in the XPAG engines have Whitworth heads, with the exception of the fastenes on the rear axles of the later T series cars, which had Unified National Fine (or SAE) threads and head sizes.
Cheers,
 
And don't forget about the French-threaded fasteners with Whitworth heads, found on many pre-war cars!

I should have said British thread instead of Whitowrth in my above post. /bcforum/images/%%GRAEMLIN_URL%%/smile.gif
 
Steve - I'm not sure about the pre war cars (depends when it was that Morris bought the Hodgkis factory), but I did refer to their use in the T series cars in my last post - "including the metric bolts in the XPAG engines have Whitworth heads". For those not familiar with the T series cars, the XPAG engines used in them used an old French standard metric bolt (Now days called a fine metric thread) with Whitworth heads on them. They are derisively called the Nuffield Mad Metric fasteners.
Cheers,
 
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