MG Sports Cars

Jim:

KUDOS!!!!

I was tickled to watch the videos! Sounds awesome!

[Glad to see the car didn't have an electrical fire. :-) ]


Whatever you want to do on the carb, I'm all for it. (You come up with something easily tuneable, and I'll volunteer to dyno tune it!)

I was there for the Q-Jet jet change, folks. It's ridiculous. Carb is only good out of the box. It would take HOURS on the dyno to get it right... :-( :-(

Max

Max is right, but to be fair there were one or two things we were missing on the jet change that makes it a little faster and easier. It's still ridiculous in my opinion but not nearly AS ridiculous. Most importantly is to drive out the pin from the accelerator pump pivot (just far enough to clear the arm, it is then pried back into place with a screwdriver. A bit hokey but it works.) Enthusiasts claim that with practice, hooking the choke linkage isn't really that bad either. We don't agree, but... at least that can be left off until the thing goes together for the last time. Last but certainly not least, later model Q-jets have a mechanism called APT, stands for part throttle enrichment or something like that, and the spare Q-jet that we have does have one of those, provided I didn't lose too many parts. It's a screw in the center of a conical dome on the float bowl and can be used to tune the primaries without pulling the cover. Of course, putting that on the carb that is on the car and working would mean making sure all the parts are there, swapping the base plates to get the right throttle linkage and other stuff, and again, some enthusiasts say the earlier carbs are actually a little better. I'm guessing we just need to put the original jets back in the current carb (and a new accel pump piston would be a good idea) and it'll run pretty good. We never did adjust the idle mixture screws either, but that can wait until the radiator and fan are sorted.

Speaking of which, it now appears that our best option on a fan is the Flex-a-Lite 298 that Graham found some time back.



[www.summitracing.com]

This fan pulls 4500 cfm and should fit. I can do a little more careful measuring to be certain before we order. It costs $369 which seems like a lot, but so far we've not found anything else that will do the job. It does not appear to come with any kind of a thermostat switch however. To get that we would have to order the #295:

[www.summitracing.com]

Which costs $90 more but has a variable speed control.

We have about 1 month left before the car goes to Pete's place. Now I have no doubt that Pete can do just as good of a job with this part of the project as I can, maybe better. I thought I'd try to build the front structure before it goes there if I could, but there's no point in messing with it until we have the parts and one of you may be able to find these parts at a better price (wholesale maybe?) or a suitable substitute. But we can afford to do this and it has to be done if the car is going to be driven at next year's meet.

I'm asking for your input, advice and suggestions. How should we proceed?

Jim

Jim, I have had excellent results on my Midget using the GM thermoswitch that simply screws into the head or manifold wired to control a relay. They are available in several heat settings, I use a 212 degree unit, and cost less than $15. Combined with a 190 degree thermostat the coolant can circulate at speed without the fan and the fan only comes on when the temp rises above 212.

I'm also a fan (no pun intended) of using Bosch fans that I get at the salvage yard from BMWs and Mercedes. They move a lot of air, cool great, and are very high quality units considering that they have to live up to the manufacturer's warranty needs. The downside is that someone would have to fabricate brackets and shrouds for them. Here's a two speed unit from a Merc I'm installing on my MGA project to reference the size. That's a TR4 radiator it's attached to. If I remember correctly it cost me $35.




Edited 1 time(s). Last edit at 08/05/2009 01:15PM by Bill Young.

Fair enough Bill, and that represents the other end of the spectrum. Time verses money. I just read a thread where the owner was complaining about fan noise and certainly a variable speed fan will eliminate most of that. Is that a consideration worth an extra $75? He would have said it was. Also, we cut corners on the radiator. We think it will be big enough but won't know until we drive it. What will it cost us to rework the front of the car if we have to go to a thicker core radiator later on? Plus, we now have to have it rodded out which means removing it and making at least 2 trips to a radiator shop and paying whatever they charge for the service. There is no shop right around the corner that I would trust so that means at least an hour's driving time doubled or even tripled. Did we save anything over the cost of a $150 aluminum radiator? In reality maybe not. We bought a set of tin valve covers for $75, paid 2 shipping charges (all donated actually) and the upper lip had to be bent to clear the head casting and they still leak. Would we have been better off with aluminum covers made by the same manufacturer to match those heads? Maybe. So I guess the point I'm making is that I personally have a very limited amount of time available to work on the car before turning it over and I'd rather make that time count as opposed to spending it running errands, rummaging through junkyards, and reworking parts to get them to work the way they should have worked in the first place.

Incidentally though, Pete's place should be a lot closer to you than I am, maybe you could help him sort out the fan? I could make suggestions, maybe even run over that way every now and then. We do have nearly a year after all to make it driveable.

As you might have guessed playing lame duck isn't a role I'm real comfortable with but I'm giving it my best shot. If I get a little impatient I hope you will all understand that it comes from being goal driven and not from anything done or not done by any of the group.

Jim

Jim, I didn't mean to imply that anyone had to do any junk yard treasure hunting. I just wanted to offer an alternative for the guys to consider. If time permits and I could get a good diagram of the area we're dealing with I could probably work up something here and ship it to Pete. The temp switch is definitely an easy thing though if you don't need the variable speed, an off the shelf GM part available at any auto parts store. Hook that up with switched power to control a common Bosch relay and you're in business. Works great with around a 190 degree thermostat in the engine and a 212 degree fan switch. That allows the engine to run on the highway without the fan if the radiator and air flow are ok and then switch on the fan when the temp climbs a bit in traffic.

re: $90 for a thermostatic switch and variable speed fan...

I don't know... perhaps a thermostatic fan switch makes the car a little more "idiot proof", but FWIW I've never had a thermostatic fan switch on my car and I've never missed having one either. It's just not that hard to turn "on" a fan manually, and a thermostatic switch would be easy enough to add at a later date anyhow.

Noisy fan? What a sissy thing to bitch about! If the mufflers are loud enough, there's no way you're gonna hear an electric fan. I thought this car was supposed to be badass? If so, fan noise should be the least of your/our worries. Celebrate loudness! "Open up your engine, let'em roar. Tearing up the highway like a big ol' dinosaur!"

Variable speed fan? I do not think that is necessary... unless the fans you buy sound like a jet engine and are maxing out the limits of their bearings. Then I could see where variable speed fan control would be useful.

My father's 455 streetrod had a temperature issue at speed. Despite improvements in air ducting he felt it was still running too warm. His rear mounted fan had a shroud and he removed it to see if it would improve the situation. It did not help, BUT removing the shroud did not cause any overheating at idle (so he left it off).

Ultimately, he fixed the problem by replacing the "corrugated" flex hose with a preformed rubber hose. Now it stays cool at speed and idle. Looks like you guys already figured that one out.

For my Sprite, I mounted a fan behind the radiator and it is on/off with a thermostat as Bill described. Cheap, and effective.

Bill, the dimensions are 17 x 27 x 3 and it's just a big ole' rectangular space. Since the lower fitting will need angled in the shroud will have to provide for that at the bottom driver's side corner. The fan from Summit may actually be too thick depending on where that 4" clearance is needed. does that give you enough info to start with? We can bolt it to what is left of the frame rails after cutting those for clearance.

Jim

Curtis, point well taken. But you'd be amazed at how comfortable this "big ole dinosaur" is going to be to drive.

Jim,

You think my fan's that came off the 2002 Camaro Z28 would work? I'm not going to be using them. If you think they would work , take them! I could do some measuring in the morning!

They just might Calvin, they look about right. I'll print that out and go out in the morning and take a good look at it. I think the critical area is going to be at the water pump pulley, I'll get an accurate measurement of exactly where that is in relationship to the rest of the radiator and we can see if we have enough depth at that point as well as how the box fits. And thanks. Do you have any of the wiring for the fans?

Jim

Calvin, I have some measurements for you to look at. All Right/Left directions are facing the rear of the radiator, or seen from the driver's position. Visualize the water pump pulley shaft as being a 3" diameter circle. The center point of that circle is centered 3" down from the top edge of the radiator core and 12-1/2" to the right of the left hand edge, 14-1/2" left of the right hand edge. Total width 27". This circle is just over 3" from the face of the core. It might interfere with the lip surrounding the right hand fan, or it might not. If it does it may be possible to trim the lip slightly if interference with the fan blades does not result. If it does, it may still be possible to slightly trim the tip of each fan blade for clearance, and we have another 1/4" or more at the edge of that circle.

Now visualize a second circle, 6-1/2" in diameter. The center of that circle is centered 9-3/4" below the top edge of the radiator and 13-3/4" to the right of the left hand edge. So yes, this circle is 1-1/4" shifted to the right of the top circle. This lower circle is 3-3/4" away from the face of the radiator core. It may interfere with the lip surrounding each of the two fans. If it does, about the only thing we can do to help it is to tilt the bottom of the radiator forward.

That's about it. Please take a look and let us know how it compares. Overall size, 27 x 17"

Jim

OK Jim,

Looking from the driver seat again here facing the fan motors. My measurement 0/0 corner would be the passenger side at the top. I'm measuring everything from that corner.(Top photo) (even though the corner was broken off some how , maybe find that piece somewhere).

Talking fan motor center location first. Right fan center 8 1/4" down from top of straight edge (0) (Not from the little tabs up on top edge), 6 1/2" right to edge (0)

Left fan center, 11 3/4"down from 0 edge at top. 19 1/2" right to edge (0)

From fan shroud outside circle to fan shroud outside circle "Across" full width measurement from 0 side to left side would be the furthest measurement is 26 3/4" (not using the tabs or straight edge measurement)(top photo).

Measurement from 0 down edge to edge 18" for shroud... could do 1/2" trim top and bottom for your 17" measurement? Probably wouldn't bother anything.

The depth of fan motors are from motor face to 1" lip furthest measurement of fan shroud (You can trim this back some) (bottom photo) 5 1/2"


From your measurements on the 3" diameter water pump pulley 3" down and 12 1/2" from the left edge, and with just over 3" from radiator face, would bring you close to the right fan but I think it will clear fine (Don't know where your fan belt rides on this pulley) The bottom photo with the 1" lip on the top of shroud(close to my wall in the photo) you will have a 2" clearance there away from the shroud face. Maybe a 1/4" to 5/8" or more from the fan shroud circle on the outside of the circle( not the fan blade). Good to go there!

The 6 1/2" diameter pulley 9 3/4" down from top and 13 3/4" from left hand edge, and 3 3/4" away from radiator( look at the top photo and look at the"right" fan support blade for the fan motor, at just below 9 o'clock position blade, outer edge, you will see a tab with a small hole on that support blade. If you measure 1" to the left from that hole, that is the center measurement for your 6 1/2" pulley center. With the 3 3/4" depth to radiator
clearance you have there,.... from the back face of the shroud to the fan shroud circle lips for both fans measure 2 1/2" out (bottom photo) if you added 1" for the depth for the top lip you would still have a 1/4" clearance still.

I think this fan setup might work for you!

I don't have any wiring for the fans, but it is a standard 2 male spade clip type GM connection.

Can you understand my garble on this, by golly I think this will work for you? I can weight it in the morning!

Is there anything else sticking out from the engine?

That is very good news Calvin! What is the overall width btw? It sounds almost like it was made for our application. There's nothing else sticking out from the engine, and I think we have room to trim back the frame rails and pan to clear. So I guess the next thing would be to get it here and test fit it. Is there anything else I can do to help with that?

Jim

The overall width measuring from the the 4 plastic tabs that stick out to hang the shroud from, from tab to tab across is 28 1/4", but if measured outside to outside shroud fan circles across is 26 3/4" cut those tabs off and mount it some other way for your 27" across radiator.

The fans are 12 1/2 " diameter circles.

If that is your address where your avatar is? I'll send it there for you. Monday will be the day I will send it. I will clean it up from all the dust on it and box it up for Monday.

Gotta love the sound of Gunpower Rd in the Blackwood forest labs!

Just maybe I can source the wiring from my friend if I have the time before Monday.

Calvin

That'd be great Calvin. The address is correct, and we really enjoy it here, far enough out to avoid the worst of the traffic and noise but close enough to be convenient. The address was just a bonus! We feel very lucky to be here. If you ever find yourself in the Cincinnati area make plans to stop by. You're always welcome.

Jim

The fan shroud that Calvin sent came in today. After some initial trimming here is the first fit:









If you can see it, the only place where clearance is inadequate is where one strut hits the lower pulley and that is easily remedied.

Jim

Well it looks like it fits in there like we thought would. "Great" I'm glad it went to good use.

Calvin

"Water Wetter" to help for temp reduction? For future think, gads of (2)x 1" row alum. rad's in Jegs for $165. Knocksensor helpful? Your eardrums probably overwhelmed with "other" sounds? Good Luck, roverman.

Preparations are underway to bring the GT to Pete's place in Sidney, Illinois in a little over a week, where a number of us are planning to gather for a cook-out or some such activity. This will mark a transition in our build program, as we move further from the actual fabrication and conversion and more towards tuning and refinements. Towards that effort, Dave VanWyck has been attempting to get some fiberglass fenders to us, we're still working on that. I expect we will find a chance to sit down informally and discuss where we are and what should be attempted between now and next summer. As always the goals have to remain somewhat flexible, but sorting out the radiator and carb certainly are near the top. Pete has given me every assurance that the car will be well cared for, but at the same time we must acknowledge that he and those who come to work on it must drive and test the car in order to tune it properly. I think we are placing it in good hands. As a driver with racing experience and a consciousness and respect for the cars of others, including his customers, Pete can be relied on, and he certainly is familiar with high powered automobiles. I have satisfied myself that at low speeds the car is safe and tractable, but as we develop power we will need to be ever alert for any signs of trouble and I can't think of anyone better equipped for that task.

So the next week and a half will be a busy time for me, as I get things ready on this end. I know several of us will not make it to Pete's for various reasons but look forward to seeing those who are there.

Jim

Looking forward to seeing you and the Roadmaster this weekend.