MG Sports Cars

have not sent surge tank yet, I plan to remove it monday 2-8-2016 at the work party we're having in Jonesville, NC.

I plan to drive RM without a surge tank or maybe do a temporary tank. any comments??

I also hope to fix the fan for demisting/defrosting

along with a few other bits like gauges

Next RM work party tentatively 2-8-2016 in Jonesville, NC


all interested petrol heads invited to assist

primary task to do:

pull the dash and fix a few things like gauges,

controls for heat/demist,

map light,

radio antenna,

change the steering shaft for one with electric power steering,

plan for future A/C,
remove cooling system surge tank for mods by Jim Blackwood


Lexington style BBQ provided
wear appropriate garage attire

start at 10 am finish no later than 7:00 pm

The cooling system overflow/surge tank was successfully removed, surprisingly it was a greater challenge than anticipated. Just a guess but, we think it may have been installed without the bonnet in place. So no other tasks were completed.
RM is now in storage in Jonesville, NC. all but one the hoses that once were connected to the tank are plugged. a one quart overflow tank is zipped tied in but it's not a recovery tank it's just an empty bottle to catch overflow.

I do not plan to drive RM until we sort out a tank to insure cooling as good as prior to the removal of the custom made tank made by Jim Blackwood

I'm puzzled about why the 5/8 hose was connected to the water pump also not educated enough to know why the heater core was plumbed into the surge/overflow tank, but what else is new, I'm a helper not a mechanic, my education is in history not engineering.

Thanks PJ, do you have my address?

The reason the surge tank is connected to the water pump inlet (using the heater return spigot) is to provide a drain to the tank and place it at or near inlet pressure, making it a low pressure point in the sealed system.

This allows vent lines from various other locations to flow towards the tank. Note, pressure differential across the pump frequently can and does exceed the value of a system pressure cap, bringing up a host of issues I'll not address right now, but the point is, there is a pressure drop across the radiator and another across the thermostat. This means the inlet side of the radiator is at higher pressure than the surge tank and any air in the system will automatically flow from bleeds placed at the system high points to the tank and constantly remove any air from the system. This is very helpful for efficient cooling, and where as here the radiator is mounted low it is quite essential.

Without the drain it would be difficult to design a comparable self bleeding system.

Plumbing the heater return into the tank is just a matter of convenience. Hose sizes and fitting locations made it the easy choice, as again, the tank is a low pressure location and promotes circulation of the coolant, with the supply side connected to the high pressure side behind the thermostat.

There are design considerations that vary between downflow and crossflow radiators, with the downflow design generally being the simpler one.

Oh, and I didn't make the tank. Gary did, using dimensions I supplied to him. I thought it turned out rather well considering.

Jim



Edited 1 time(s). Last edit at 02/09/2016 11:25AM by BlownMGB-V8.

how apt a work day march 21 for RM in jonesville, NC?

Dale from Motion machine drove RM yesterday, I'll resize photos soon and post. Im on a 3 day road trip getting points for the Moss motoring Challenge 2016.

Its the final year for this year long scavenger hunt, I may be in your area sometime this year.
If anyone wants a couch surfer, pm me I hope to visit all 48 staes this year taking selfies.

Quote:

how apt a work day march 21 for RM in Jonesville, NC?

I think we can make that work.

It is getting tough to juggle the Roadmaster, 2 different ChumpCars in different directions, actually make race in the TR6 (I was sick & did not make the treck to VIR), Jim & Melinda Watson's Springtime in the Smokies, our 20th annual British V8 Meet.......and oh yeah, I need to work on my car, too! ;)

The Roadmaster is now in Tennessee....

Here's Jim Watson, probably at a cruise-in near Knoxville.

great photo, RM looks mean from that angle

How's she running?

The Roadmaster was delivered to Blackwood Labs at 2:00 today.

Took it for a ride around the block and noted a couple things needing attention. I ordered a new heater valve (TR-6 valve, $30) and will try to build a new surge tank before Louisville. Otherwise I was impressed with how nicely it drove.

I'm tracking down the stock gages I sent out for the car and will continue to look into that problem.

The car needs a 3rd gear synchro, if anybody has one in good shape from a T5 we could use it, or possibly install a new one if someone could recommend a good source. Unless I'm mistaken, changing that will require the countershaft to be dropped down and the mainshaft removed, any pointers on the proceedure are appreciated.

It looks to me like it may be possible to adjust some or most of the play out of the steering rack. The one from Jim W. turned out to be not MGB. So, I will do that adjustment and report back. I've talked to Mikey about EPS.

I'll also have a look at how the A/C compressor might be mounted.

Jim

I would like to coordinate its arrival in Louisville with you in order to obtain parking, etc.

We need TWO sets of keys.

No problem Rick, when do you plan to get there?

Jim

I'm arriving on Saturday, June 11th.

I can bring the car down Saturday, just let me know when and where and I'll meet you.

Jim

Almost have the Roadmaster ready for the Louisville meet. I made a new surge tank and it's installed. Re-routed the drain so it can function as it should. I'd be happy to explain the details in person if anyone is interested.



I also installed the new fuel pump that was bought for the car. Honestly guys, I don't know if this made any sense. That's at least the 3rd pump of that type that has been on the car. This engine has the ability to instantaneously suck down fuel like almost no other one in the fleet. If we are having a starvation issue maybe we should bite the bullet and install a *new* high flow pump of a type suitable for the use.

I installed a TR6 heater valve on Jim Watson's recommendation, then found it needs the GT6 valve which works opposite of the TR6 one. (They look almost identical) One of those is on order and may get here tomorrow or the next day. If so I will install it. Anyone want to buy a new TR6 valve? (Hasn't had fluid in it yet)

I also installed the new replacement steering column we've been carrying around for a year, after checking the rack shims and universal (both good). The play is gone, part was in the column's slip joint and part was at the steering wheel hub. All gone now. Charles and Mikey are working together on an EPS unit using the old column, which is good because it fits better than the replacement.

The heater knobs have mismatched gearboxes, one old style and one new. Sorry, it's all we had to put in at the time. So for now, I've installed a new knob on the left so the heater valve can be adjusted. We need an old style gearbox to fix this problem.

Haven't had time to do anything about the gages yet but the good news is that I have a full set including the voltage regulator. The tach can be run off one coil pack and the speedo can be run off a cable. I see no real problems there, it just needs to be done.

Jim

The metal fuel line to the carb body needs a brace. It was leaking fuel at the carb due to vibrating loose.

While I had it on the rack I test fitted two A/C compressors, or rather tried to. A Sanden and a GM A4 "pancake" compressor. Neither one would fit in the low spot on the driver's side between the frame and the block. That spot is definitely a non starter.

That leaves the location in front of the driver's side head, and above the oil pump drive where the distributor used to be, basically two variations of the same place. The A4 should fit here. The Sanden might but it'll be very tricky, and hood clearance gets into the picture. (Incidentally I do not have a known good A4, just a questionable take-off.)

This location will require a complete re-routing of the upper radiator hose, including re-welding of the thermostat neck and extension, but this can be done. However, nothing will happen here until after Louisville.

Jim

OK, I've done everything I will be able to do before the show. As it now stands, the car is in very good shape and comfortable to drive. The steering is a little stiff from the solid bushings in the column but hey, no play. The new EPS will fix that.

It still has a lean bog on acceleration, the pump can't keep up. 3rd synchro is unchanged.

But hey, temp holds steady at 190 with no problems, and best of all it now has a full compliment of functioning gages!

Stock Fuel, Tach, Speedo, and Temp. Curved bezel style. White faced Oil pressure and Voltmeter in the center. Doesn't look bad really, at least it is symetric.

I think the fuel gage will be accurate but still have to check it out. At about 3/4 I put in 4.4 gallons.

The tach seems reasonably close. Shows about 1700rpm at 70mph in 5th. That was a trick btw, I wired the supply from one (EDIS) coil pack through the tach, tried both polarities and picked the one that gave the lower reading, then used a screwdriver to adjust the calibration pot for the lowest reading. Didn''t have a dwell tach to compare it to but at least it is usable and best of all, no mods to the 4 cylinder tach. We could run Dan's spreadsheet to see how close we are, the rear tire size is 245/45-17.

The speedo reads 10% low, so 70 mph @ 77. With a 19 tooth gear installed, a 17 should bring it to within 1 mph. That was also a trick. Hey Guys! I found how to use a stock speedo cable with a T5!! All you need is the nut off a GM speedo cable. File the inner cable end down so it fits in the GM drive gear, then cut the threads off the big nut on the MG cable leaving a washer. Sand down the outside of the washer to fit in the GM nut (a belt sander works nice, letting the washer spin on the cable to get an even perimeter) and then bolt it up! Presto!

The temp gage is wired to the wrong sender but it is usable until we can install the correct one. I didn't have an identifiable MGB sender to use. At 190 the needle is a bit south of the "N". I made a mark with a sharpie. With the right sender it will read like any MGB.

So you may ask, why didn't we use stock gages originally? Mainly because we didn't know how to make the speedo and tach work right. We did not have EDIS at that point so we couldn't use the single coil pack trick, and we did not have a mechanical drive for the speedo. Thanks to Steve DeGroat for that btw, I pulled the drive out of the 4 speed he brought up for the Chump Car and it works great. (Also Steve, the tool kit you donated for the RM is now back in it's spot behind the driver's seat.)

And that's about it.

Rick, I will call you a bit later to coordinate.

Jim

Wow Jim you've gotten a lot done!