MGA MGA 1500 Thermostat Blanking Sleeve

[ronzet]

MGA Affectionados,

My 1957 MGA is now on the road after a frame off and I am working out the bugs.

I neglected the boil-out of my radiator and had experienced overheating due to my negligence... This has been rectified..

However, It still runs on the hot side even with a 160degree thermostat installed. After much research I discovered that modern thermostats are not completely compatable with the 1500. It appears that the design of the head has a thermostat bypass that allows hot coolant to recycle into the engine elevating the temperature. The MGA GURU's site recommends a fix by using a blanking plate with a modern thermostate set inside.

Has anyone used this technique and what has been the results.

My option is this or purchasing an aftermarket original design from Moss or VB but, with some of the experience I have had with the 'made somewhere else' parts from these resellers I am a bit reluctant to shell out the $45 for a part that will last only a little while...

Thanks...

 

[ronzet]

Soooo, OK no takers....

I will receive the blanking plate from Moss this afternoon and will install it this evening along with a 160 degree thermostat as recommended by the MGA Guru site...

I let ya'all know how it turns out!!! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[burgundyben]

This may have been addressed on your car but here goes.

I had a 100M Healey, very nice car, had just been restored, but had an oil pressure problem, it was just not high enough, eventually one big end gave out so I pulled the lump to rebuild it, turned out it had been built with -20 crank and -10 shells on the big ends hence the problem. Lack of comms beween engine builder and machine shop I guess.

I thought I would replace the core plugs, think you guys call them freeze plugs, when doing this I had a poke around in the block, I found a great deal of rusty sludge in the bottom of the water jacket, took a great deal of effort to get it all out, had the block upsidedown on an engine stand with a long think tube fitted on a wallpaper steamer to wash it out. Agitatyed it with a welding rod.

The outcome was 60 psi oil pressure but she ran 15 degrees cooler. How clean is you block inside?

 

[ronzet]

burgundyben,

I rebuilt the engine having it bored out to 30/1000th over on the pistons and 30 under for the rod bearings and mains. The engine was hot tanked in the process and was pretty as a picture and clean as a whistle... My oil pressure is around 60psi and the puppy purrs (is that a mixed metaphore?? I don't think puppies purr)... anyway...

The heating problem has mitigated somewhat now that I have the radiator cleaned out... But, the original thermostat came with a blanking plate that prevented water from bypassing the radiator. I have no idea why MG's engineers designed the head that way but there it is...

I purchased a blanking plate and will install it this evening with a modern thermostat (per a recommendation) and give that a try...

Thanks for your comments and observations.. /bcforum/images/%%GRAEMLIN_URL%%/cheers.gif

Great car, bye the way... 100M.. /bcforum/images/%%GRAEMLIN_URL%%/thumbsup.gif

 

[ronzet]

MGA Affectionados,

I installed the thermostat blanking sleeve along with a modern design 160 degree thermostat in the A last night.

This seems to work well... My temperature dropped by 20 degrees and now runs nicely in the 175 degree range...

Just thought ya' should know.. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[Steve_S]

Thanks for the update. Still need to see this car of yours!

 

[RonMacPherson]

That "barn" you found, is that off towards Temecula?

 

[ronzet]

Ron,

<div class="ubbcode-block"><div class="ubbcode-header">Quote:] That "barn" you found, is that off towards Temecula? [/QUOTE]


In all honesty.. /bcforum/images/%%GRAEMLIN_URL%%/blush.gif I haven't the foggiest notion where the barn is located. I found the picture on the web and thought it fit my sentiment perfectly.. /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

 

[ronzet]

Steve,

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Still need to see this car of yours! [/QUOTE]

I posted a few pics on a different thread.. none of which are of the 'On the road' status....

Patience, my friend, patience.... /bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif

 

[ronzet]

Steve,

Pictures posted in thread 'the beat goes on'

Thanks for asking /bcforum/images/%%GRAEMLIN_URL%%/cheers.gif

 

[Rob_Edwards]

Glad to hear your car is running better. The only comments I'd make are:
1. 160ºF is too cold -- you'd be better off with the engine closer to 200ºF. Running it too cold wastes fuel, reduces horsepower, and increases engine wear.
2. The thermostat cannot prevent overheating -- it can only prevent overcooling. If the engine is making more heat than the cooling system can shed, it will overheat with a 160ºF thermostat just as surely as with a 195ºF.
3. I use a blanking sleeve + thermostat (195ºF) in my B and it seems to work well.

If you're interested, here's a little thing I put together about thermostats:
https://www.mgcarz.com/thermostats.html

HTH!

 

[Steve_S]

I run a cool thermostat as well. In the So Cal summer, temperatures can reach 110+ degrees. Getting the car down to 170 instead of 180 on a long decent can make a big difference on the next climb. It's easy to overheat on the long, steep grades of the local mountains.

160 is too cool for optimum efficiency, but it won't harm the engine. My MGC runs no hotter than 160, sometimes much lower. The TC typically runs from 40C-90C depending on its mood. But the A and the Bs heat up pretty quickly on their own so the cooler thermostat helps.

 

[Rob_Edwards]

Hate to disagree, Steve, but over the long term it will harm the engine. A too-cool engine will not drive contaminants (mainly fuel that washes past the rings t cold start, and water that is a by-product of combustion) out of the oil as quickly. This creates engine wear. This, coupled with an oil cooler on a B (do As have coolers?) that keeps the oil too cold most of the time, will greatly increase engine wear....

HTH!

 

[DonK]

On my 1600... every summer I remove the thermostat and insert the Moss blanking sleeve. With a supplementary electric fan running at stops and in slow traffic, the temp holds at around 180 degrees -- even in the sun -- even at 95+ outside temperatures. Just got a beautiful polished aluminum radiator from Pace Products in England, which should eliminate the need for repetitive re-soldering of the reservoir on the old black painted radiator; and the car does have a small oil cooler. Before I did all this stuff, we suffered constant summer boil-overs -- especially when climbing hills and/or when holding at over 3500 revs. My aim is to have a reliable year-round car that can be a daily driver. I think we're pretty close to that now.
DonK

 

[Steve_S]

Defining "too cool" is the difficult part. Doug Smith advises that 120-160 will do no harm to a C engine. Some engines need to run 230+ (not an MG!). My B has typically run from 160-180 for its entire life. The engine has gone roughly 100K miles between builds.

BTW, some MGAs do have oil coolers. It was optional. Their effectiveness on a stock MGA is questionable due to the mounting location.

 

[ronzet]

Gentlemen,

This is a great topic. Just to fill in the blanks on my A, even with a 160 degree thermostat, along with the blanking plate, my car runs in the 185-195 range. I may be running the carbs a bit lean and will undertake an adjustment and balance as time permits this weekend.

Suffice it to say that the flushing of the radiator, addition of the blanking sleeve along with the 160 degree thermostat has made a marked improvement in the cooling performance.

Once the car has had a bit of a break-in period along with the necessary adjustments and tweaking, should the engine start to run below the 175 degree level, I will replace the thermostat with one of a higher rating.

Keep in mind that I live in San Diego where people run for heavy woolen lined clothing with the air tempurature reaches anything below 65 degrees.. so a high ambient temp is pretty much the norm...

By way of advice, based upon this recent experience, cutting corners as I did in the installation of the original, unflushed radiator, is ill-advised and downright hazardous to your car.....

 

[Rob_Edwards]

Wow -- I'd never want to see an engine at 120ºF as normal temperature. That's far, far too cold as far as I'm concerned.

Ron, your engine running 185-195ºF with a 160ºF thermostat is a perfect demonstration that a thermostat only set the minumum temperature, not the max. 185ºF is a little chilly for where I like to see my B. I think 200-ish is a better place to be....

HTH!

 

[ronzet]

Rob,

Thanks for the comment. I like to see my A running in the 175-195 degree range and agree with you that anything lower creates its own set of problems.

My B runs closer to your 200+ range under normal operating temp. My first 'A', a 1957 1500 that I owned back in 1965, ran below 200 when the car and the engine was less than ten years old so I guess that is where my lower temp bias comes from.... /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

 

[Steve_S]

My MGA runs best around 175. The BGT runs bets at 195. the B roadster likes 175-180. Funny how similar cars can ahve such different personalities.

 

[DonK]

Re: location of oil cooler on MGA: you're right. Blocking the radiator creates a minus that may not be compensated for by the plus of having the oil cooler. I've been considering lower positions, though the thought of road-debris damage has kept me from making the move. Re: cooling in general, it DOES help to run with lowest possible proportion of anti-freeze to water. Highly variable temps, like we have in the midwest, make the exact best proportion problematic. Also: I've never tried that aftermarket shroud sold by Moss and others. The new aluminimum radiator seems to make it unnecessary.
DonK