MGB: '70 GT distributor

Helllo all, just more questions on my running down systems on the old GT. Put a vacuum on the vacuum advance and the engine idle decreased, and the whole vacuum assembly on the distrib moved back and forth. Way too much. Haha sounds like it is working in reverse! Been looking around and Ebay has some appealing units. When out I could tell the advance was not working when pushing it abit, felt like no power.
The engine in my GT is not original equip. Head has no air pump inputs as in the manuals. The engine id plate has even been "lost"? see pic

Saw a rear axle disc brake conversion also on ebay today for the B's. Anyone an old SNL fan...."I've got the FEVER!"

there are two basic vac advance units. one for manifold vac and one for carb port vac. they would be "backwards" from each other.

How is yours connected to the vac? What if you changed it to the other source?

what is the number on the distributor (small numbers stamped into the dist body)? I think stock should be 41288 for a 1970 and this ought to be port vac. If it is 41491 that's a 71 and I think it is manifold vacuum.

don't waste your money buying yet another core from ebay. send the one you have to advanced distributors and have him rebuild it...i think he can even change out the vac advance to the correct flavor.

He'll probably be along later this evening

What Mac said.
As for your engine, the air rail ports have been plugged and it appears your Tstat housing has been ground off where the air pump ear was. I cant tell where the advance hose goes but I think I see it going over the VC at the rear.
RS

Thanks for the replies Mac and Robert.

Just on vacuum line to the distributor. It is from the SU manifold closest to the driver. I would not mind going for another distributor. Are the ones on EBAY that are from the UK really from China??? Complete units that take Lucas parts. They are inexpensive so I wonder?

I'm enjoying getting back into MG. When I drive it, I feel like I'm driving a car. Most new cars are so insulated which is nice also. Best of both worlds.

I'm going to be the first to say it - send your distributor to Jef Schlemmer!

Humm, what is the turn around time on a "Schlemerized" (SP) distributor??

Bryan

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it is not clear to me from your statement where you are picking up the vacuum. (SU manifold...there is only one) From the rear carb (the one closest to the driver) on the side of the heat shield away from the engine. OR the manifold (on the engine side of the heat shield) from the balance tube between the two runners.

Next, the distributor number. That will tell if it is stock 70 issue or not. The stock # was in my earlier posting. If it is, the vac line should go to the rear carb on the carb side of the heat shield. If it is not stock, it could be either way. Now...should you have the HIF-4 carbs (no float bowl on the side and the bottom of the carb is rather squared off) they you do not have a vacuum port on the rear carb and you will need a vac advance unti designed to work with manifold vacuum not carb vacuum (the two run opposite of the other, when manifold vac is high the throttle is closed and there is virutally no port vacuum. when throttle is open, there is little manifold vacuum but lots of port vacuum -- to the vac advance unit is going to run backwards if it expects A and gets fed B).

It will run with the wrong connection but it runs really weird.

Often Jeff has in stock items for return shipment. otherwise about a week is what I've seen. jeff@Advanceddistributors.com or find him here on the board (yes advanceDDistributors.com....two Ds ) While you are at it get his deal on the Pertronix AND a couple of his high quality rotors.

Bryan,
Welcome to the Experience. As you're in a warmer climate, replacing the seal between radiator and support will aid in cooling a bit.

Number 46 in the Moss catalog...

It is hard to tell for certain but I believe that the Tstat housing has been replaced with one from an early car as opposed to being ground off. The angle of the inlet is wrong, it should be a bit more parallel to the radiator. That one appears to be placing stress upon the upper hose where it comes off the casting.

Jim B.

Go with Jeff on the dizzy, and don't spend your money on the rear disk brake coversion.

That thermost housing is from an early B, '62 to '67, but it has been rotated so that it will point to the later radiator's input. The '68 to'74 used a cast iron assembly with a mounting boss for the air pump. The same housing was used for UK specifications but without the mounting boss. Send the distributor to Jeff. You won't be dissapointed. RAY

Thanks to all for the information. Looking into Mr S's site.