MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Moss Radiator Shroud for MGB MK I?

Has anyone installed the radiator shroud being sold by Moss for the Mk I MGBs? How is the quality of materials and the effect on cooling?
Thanks,
Doug
Doug Brooke

Doug, I've seen the shroud displayed by Jeff Zorn from Little British Car Co. at shows, it looks like a quality product, but I have too many priorities to spend the $40(??) for it at this time and my car doesn't run too hot. I would be interested in hearing how effective it is too.

BTY, Jeff's prices are a little under Moss's, you might save a $ or 2, check his website. (I have no connection with LBCarco)

Bud
budman72

I just bought a shroud from Jeff for my 66B (Mark I). I haven't put it on yet, but at a show I was at on Sunday, I saw one installed, and it looked fine.

The shroud comes with an info sheet explaining how it works and percentage change in the cooling . . . but damned if I can find the sheet at the moment. If I can dig it out later, I'll add a post here with what it says.

Anyway, everyone I've talked to who has one recommends it as helpful to keeping the engine cooler at idle, when the measly three-fin fan doesn't do much in the way of cooling. Shroud forces fan to pull air through the radiator, instead of around it.

Also, don't forgot that there's supposed to be a piece of foam between the top of the radiator and the support mount, where you see an open space. I'd forgotten about it, until I saw some Bs at the show with them. A piece of air conditioner sealer foam will do it. I also saw a car with a piece of round water pipe insulation there. (It's a lot denser.)
Kim de Bourbon

Doug,
Interestingly, I posted this on the MGA area a couple days ago. Altho it is really specific for that application, the shroud's are so similar that I anticipate that my comments are at least in part applicable.

"When I installed a Moss type plastic shroud on my MGA, I had to make some additional modifications to get correct and effective fit. I did NOT have your problem, Mike, but I did in time have a problem with the plastic chosen buckling.

What would happen was that as it heated up, it expanded faster than the surrounding sheetmetal which holds it in place. This caused a buckling of the shroud out at the center of the top and bottom. This not only caused a small gap between the leading edge of the shroud, top and bottom, but also contributed to the opening at the rear of the shroud being distorted enough that its relationship to the tips of the fan became questionable, possibly causing some turbulence between the fan and radiator, and affecting cooling.

"To eliminate this possibility, I had to force the top center back against the top of the radiator and rivet it in place {to the sheet metal fan guard on the MGA radiator} with pop-rivets. On the bottom, I had to fabricate a sheet metal "strap" which clipped over the bottom edge of the fan opening, and then pulled the bottom center up tight to the bottom of the radiator, passed under the bottom tank, and clipped to the forward edge of the bottom tank. {In the case of an early MGB, perhaps a strap anchored to the radiator bulkhead or a clip like the one used on the bottom of the MGA radiator might work?}

"I am sure there are other ways to accomplish this, but the point is that it made for a much more effective shroud, and the question of fan turbulence and proper relationship to the fan was eliminated. FWIW."

Norman Fair made a good observation that a metal brace across top and bottom might be a better and easier move to the same end. A small sized L-extrusion would likely accomplish this if riveted to the top and bottom edges. Actually, the maker could mould these in place, but I suppose the cost might jump to a couple hundred dollars? I think a bit of aftermarket field engineering on our parts can do the job just as well.
Bob Muenchausen

I installed one of the Moss units on my 67BGT a few weeks ago. In an effort to solve an overheating/headgasket problem I had the head milled and decided to try the shroud. It took quite a bit of trial fitting and cutting to make it fit without the fan hitting it. After four or five cycles it worked. The car doesn't overheat now. Was it because of the shroud, the flat head surface or the new thermostat? Unfortunately I couldn't test it after each component replacement.

Chris B

Because of the climate around here and the internal engine changes on my '69 MKII I also tried the shroud. The catalogs say its only for MKI's but it fit perfectly fine with no adjustments necessary. I also fitted the yellow 6-blade fan and enlarged the radiator capacity and efficiency. No cooling problems even in 100+ deg.F heat in traffic in over a year now. Its quite comfortable to look at the Temp guage and see it rock steady at N while stuck in traffic.

Bob: The plastic mine is made of is quite hard and steady. Hasn't deformed at all since installation. Its possible that they've changed the formula or to another "better" (cheaper?) type.

Luigi
Luis

Mine appeared to be some sort of high density Polyurethane or Polyethelene. It was fairly ridgid at room temps, but once well heated on the road (guessing a temp of about 150 F + ) it became more pliable and it was after a few month's use that it seemed to develop the buckling I mentioned. I am not sure if there may have been a change in plastics or there is more than one supplier??? I just mentioned it as there might be others who could be faced with the same problems.
Bob Muenchausen

Doug-
Having a power-enhanced engine I was concerned about overheating while pulling through the mountains on hot summer days. The sole example of the plastic fan shroud that I've seen was buckled, just as previously reported in this thread. I fabricated a shroud out of heavy gauge aluminum sheet metal and reinforced the attachment flanges by riveting on thin steel strap. I also added a circular flange around the fan aperture that has its front and rear edges repectively equal to the leading and trailing edges of the fan blades so that the drawing power of the fan would be maximized rather than having the fan just whip air around inside the engine compartment. If this sounds like a horrendously difficult project, let me assure you that it's not. If you remove the radiator, can use a measuring tape, use a yardstick to draw the lines on a large piece of cardboard, you can lay out the design and have any sheetmetal shop do the bending and welding. Paint it any color you like.
Steve S.

Thanks to everyone for your insight and suggestions. Not sure which route I will take, but I will certainly consider the information that I've gained here.
Doug
Doug Brooke

Hi Ya'll,
Correct me if I'm wrong. What I understand from your conversations is that - in the current Moss catalog, page 66, Fan Shroud #459-685 is for '62-67' only, BUT - it will fit in a '71 MGB ?
If so, I'd like to get one. I've had 2 cars blow thier engines from overheating, so I'm parinoid. Any words of wisdom would be appreciated-
Bill
William Powell

William-
The most common causes of overheating are a bad thermostat or crud in the cooling system. The first is easy to fix, but the second takes some serious work, but you can do it yourself on a Saturday morning. Rust and mineral deposits are excellent insulators, trapping heat inside the engine. After 20+ years of service, you'll be amazed at what's in the system. Drain the system, refill it with plain water, and add some radiator flush. Run the engine with the heater valve open and let the solution circulate, then drain the system and remove the radiator and flush it with a garden hose. Now comes the fun part. Put it back in the car and hook up the hoses. Now pour in some hot water heating system descaler and fill the system with water again. Run the engine with the heat valve open, then drain the system. Remove the radiator and flush it out with a garden hose. This time you'll be astonished at what will come out. Reinstall the radiator and refill the system with a mixture of 25% antifreeze and 75% distilled water. Be sure your radiator cap is in good shape. If you don't know how old it is, it's cheap to replace.
Steve S.

Steve S,
REMOVE THE RADIATOR? That sounds like a scary operation for a novice but upon further examination I see that there's only 2 hoses (top & bottom) and 4 bolts. Am I right? I want the whole heating system flushed out - sparkleing inside- and refilled with a cooling solution that would guarentee never to overheat.
Might as well replace the hoses while I'm at it and also the fan belt.
R'grds,
Bill
William Powell

William, it should be six bolts and two hoses. Pretty easy, but getting the hoses off are a pain. Yes, good idea to replace while they're off. I bought the Teflon type (can you fry in them?) cost a little more but they do they seem very strong./

If you have the original metal fan I would replace it with the six blade plastic. The plastic fan is more efficient and there have been threads on the BBs lately of blades coming off and ripping into the car.

And to answer your question about the shroud, yes it should fit, mine did, but take what was said above into consideration. You may need to "enhance" it a little to fit your car. The shroud fits onto the six bolts that hold the radiator on the engine side.
Luis

Steve S, if you have a digital camera, or a scanner, might it be possible for you to send me a JPEG of your custom shroud?
Ken R
Ken Rich

William-
If you're really afraid to do it yourself, your friendly local radiator shop will be only to happy to take your money to do it for you. Be sure to tell them to add a petcock to the bottom of the radiator (May as well make paying somebody else worthwhile by having tham do something that you can't do yourself.)
Ken-
Sorry, but I have no digital camera (still using 35mm film), and wouldn't know how to operate a scanner (New Age Dinosaur). I'm thankful to have the skills to post on this BBS.
Steve S.

There used to be someone who had done all the design and fabrication work that Steve S. mentions and was marketing a shroud very much as he describes. Whether they are still out there or not, I don't know, but I bet a search on Google might dredge up their efforts, if they are still around. Seems like I saw these ads in either the NAMGBR or NAMGAR mags.

Paul Kile, if you are out there, do you recall these and who might have been marketing them??
Bob Muenchausen

Thanks anyway, Steve, and thanks for your lead, Bob. Don't be fearful of these technologies, Steve. Be fearful of how quickly your "investments" )(ha ha!) become next to worthless. I switched from Mac to Windows 98 at age 60, and taught myself scanner skills and digital editing at 62, and i really am a dinosaur- still believe in odd ideas like the value of work, marriage, and family, and personal responsibility, and law and order and respect and democracy. And LBCs. And especially, the MGB.
Ken R
Ken Rich

Ken-
Yup, know what you mean. I still cling to those ancient and hallowed beliefs, too. Today I learned from a secretary how to put up a screensaver. I'm catching up. I've even bought a program that uses a magic box to turn spoken words onto print on the screen. That should speed things up. Maybe I'll even find out how to run a scanner someday and then I can get my personal website up (finally). I'm not really stubborn, but my wife describes me as a determined soul. I'm a glutton for punishment, too. But then, you know all about that. We MGB owners always have that in common.
Steve S.

The 62-72 MGB's used a long shaft water pump. If you fit the plastic fan you have to fit the short shaft pump or the fan is too close to the rad. The plastic fan usually overcomes the cooling problems on the early cars. Interestingly, I fitted the rad from my 67 GT to my 7o Rdstr and had no cooling problems, put it back in the GT & it o'heats in traffic.!! Perhaps that's why they went to the recessed grille???
In our 72 B race car (130 bhp at the wheels) I had a '78 rad recored with a high efficiency core & fitted an electric fan. It ran so cool I had to fit a thermostat. Never needed a fan even in heavy traffic! so took it out.
Garth Bagnall

FYI, Doug and all, I finally found the instructions that came with the MGB Radiator Shroud. (No, I haven't installed it yet!) This is the one sold by Moss and VB.

Says this shroud fits all '62-'67 MGBs with the original 3-blade metal fan, and that clearance is tight by design. Says installation takes about 20 minutes (40 mins. without air tools).No need to disconnect radiator hoses.

Here's what it lists as "Radiator Shroud Effectiveness Data"

----------------------

At idle (1200 rpm), this shroud increases measured average velocity of air over the radiator surface from 13.3 feet/second to 16.0 feet/second.

This average velocity increase results from drawing air through the sides and corners of the radiator that previously (without a shroud) had very little flow. Air flow measured through the center area of the radiator showed no change.

The net effect is a 20 percent increase in average velocity, which is equivalent to a 20 percent increae in the volume of air being drawn through the radiator (cfm).

This increased cooling capacity wil lengthen the amount of time you are able to leave your MG idling on a hot day before overheating, or even prevent overheating entirely, depending on the outside temperature, your idle speed, coolant mix, etc.

This shroud will NOT lower your normal operating temperature. That temperature is reached quickly without radiator involvement, and is determined by your thermostat (usually 160 degrees to 180 degrees) The shroud WILL, however, increase your MG's capacity to cool, thereby keeping your car from exceeding your normal operating temperature as severely or as often as without a shroud. In essence, it helps delay or prevent overheating.

At speed, the radiator shroud is much less important. Non-rigoroug experimentation shows approximately an 8 degree drop in operating temperature at 55 mph on a 75 degree day. This figure is based on operating an MG without a thermostate (in order to reach a steady-state condition) both with and without the shrod while recording the gauge temperature.

Other important points for maximum cooling:

1. Make sure you run a proper 50/50 coolant/water mixture
2. Use a surfactant additive like Water WetterŪ for great efficiency.
3. Make sure your coolant system is full, and your radiator cap fits tightly to avoid evaporative loss.
4. Make sure you are not missing the foam rubber packing piece for sealing the air gap at the top of the radiator
5. Make sure your timing is properly set. Poor timing = overheating.
6. Make sure your thermostat opens fully to allow maximum coolant flow to the radiator.
7. If your radiator is old and filled with mineral deposits, no amount of "extras" will be a better remedy than a new core.
Kim de Bourbon

This thread was discussed between 13/06/2002 and 21/06/2002

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.