1977 2500M Cooling
1977 2500M Cooling
Author
Discussion

jastx

Original Poster:

147 posts

176 months

Tuesday 31st July 2012
quotequote all
My M isn't very happy in our 35 - 37C temperatures here in Texas lately. It pegs the temp guage after several miles. Adrian once mentioned make sure the latest cooling updates are installed. Can you please tell me looking at these photos if my cooling system is the latest? Single pusher fan in front of the radiator, puller fan behind. A fiberglass shroud completely covers the back of the radiator directing air towards the puller fan which is completely enclosed by the shroud. Puller fan pic shows its shroud removed. I have not yet replaced it after my rack mount update -- may be contributing to my problem.

Thanks!

John




whitewolf

751 posts

188 months

Tuesday 31st July 2012
quotequote all
Not sure but i do run a taimar with the sand small rad.

Mines been recored, i run twin 8" fans on the rear of the fan from a kenlowe sensor in the swirl pot. Temperate relays for each fan as back up. Also new thermostat.


The kenlowe is adjustable so could knock it down a few degrees for the warm temp.


With my setup I've had it idling for nearly an hour fans working on and off as should do and was ok.


My only problem was a leaky otter switch and thermostat housing weep.

ATE399J

732 posts

259 months

Tuesday 31st July 2012
quotequote all
Looks like your "pusher" fan is the wrong way round, convex side of the blades should be closest to the radiator. The cowling (or the lack of) would probably make a big difference since your "puller" fan seems to be some distance from the rad. Fans need to be as close as possible if there's no cowl or all they'll do is suck air from the engine bay rather than through the rad.

Phil.

Slow M

2,862 posts

228 months

Tuesday 31st July 2012
quotequote all
Get/make the missing shrouding, and buy TWO pusher fans that have individual shrouding at their perimeter. This forces the air through the radiator, instead of simply pushing air AT it, and allowing the excess to escape out to the side(s). Also, make sure your fan clutch is working. OTOH, with the aforementioned set-up, you can get rid of the engine mounted fan.

Best,
B.

GadgeS3C

4,684 posts

186 months

Tuesday 31st July 2012
quotequote all
I believe that the US spec cars (based on the wiring diagram and this had 2 fans. As well as sorting out the issues mentioned above might be worth the upgrade.


thegamekeeper

2,282 posts

304 months

Tuesday 31st July 2012
quotequote all
nForget about "latest cooling updates" whatever they may be (no doubt we will soon find out). You dont say if the temp rises when you are moving or staionary so I,ll assume its while you are moving. It will certainly be the last of the 3 2500M cooling systems so other than upgrades to more modern materials, fans etc there should be no fundamental problem with what you have if its working properly and in good condition, its been OK for the last 35 years .

There are only 2 fundamental reasons temperature of cooling system rises above what it has normally been running at 1) More heat into system 2) less heat out.

Usually more heat in is a result of leaking head gasket, and as the car runs hotter then a failing gasket will get weaker and the ehgine will get hotter and the gasket will fail. Have the cooling system pressure tested to diagnose or eliminate.

Less heat out is more likely. People assume that because there is no water leaking from rad its ok. If its been in there a while several things can affect its performance, sludging up being the most likely so only a percentage of the radiator is cooling the water hence the gradual worsening of the problem over a period. Buy a now very inexpensive infra red temp detector and see if you have any areas that are cold, probably blocked, try flushing.

The primary function of the rad is to exchange heat from water to air, by far the most common problem in my limited experience is the front of the rad being blocked with flies etc and in a dry dusty environment just common build up of dust. Nobody ever looks at the front of a TVR crossflow rad, its hidden under the spare wheel! If air isnt passing through its not exchanging heat to air. Try GENTLY blowing with an airline from the back to the front of the rad, You will probably be amazed what coes out and thats all stopping air flow. If the cooling fins of the rad come out too then that indicates the next point about the state of the core. The ambient temp really is not that important, its the difference between the water temp and the air and with water at 88 degres and air at 35 there is a sufficient temperature gradient for effective cooling. The next commonest failing is the contact and therefore the efficiency between the cooling tubes of the rad and the cooling fins. Check if they are loose, if they are they wont be efficient.

Check your anti freeze strength and your ignition timing.

If its none of the above the blame global warming, something we need in UK right now, bring back leaded petrol.

ps the infra red temp detector is a VERY useful tool, can be used to measure brake temps, so detecting binding, wrong pad material etc, exhaust temps so helping find missfires and lots of uses around the house. Buy your wife one for her birthday.



Edited by thegamekeeper on Tuesday 31st July 18:09

baldies

29 posts

287 months

Tuesday 31st July 2012
quotequote all
Thought my experiences with my 79 Taimar might help.
I run a std upright rad with a single fan behind the rad - no problems in UK temp.
Last year I had my "tired looking" rad recored with 3 cores as per Adrian Venn, I also fitted a set of new water pipes.
The fan had to be fitted the opposite way round to previous in order to clear the rad, is only approx 10mm clear of the rad, with no apparent reduction in cooling ability.
However I have had a un-related cooling problem caused by the seal failing on the 13lb expansion tank cap.
New expansion tank & rad caps fitted & all is well.
Recommend you consider new caps + water pipes as well.
MikeS

heightswitch

6,322 posts

272 months

Tuesday 31st July 2012
quotequote all
thegamekeeper said:
nForget about "latest cooling updates" whatever they may be (no doubt we will soon find out). You dont say if the temp rises when you are moving or staionary so I,ll assume its while you are moving. It will certainly be the last of the 3 2500M cooling systems so other than upgrades to more modern materials, fans etc there should be no fundamental problem with what you have if its working properly and in good condition, its been OK for the last 35 years .

There are only 2 fundamental reasons temperature of cooling system rises above what it has normally been running at 1) More heat into system 2) less heat out.

Usually more heat in is a result of leaking head gasket, and as the car runs hotter then a failing gasket will get weaker and the ehgine will get hotter and the gasket will fail. Have the cooling system pressure tested to diagnose or eliminate.

Less heat out is more likely. People assume that because there is no water leaking from rad its ok. If its been in there a while several things can affect its performance, sludging up being the most likely so only a percentage of the radiator is cooling the water hence the gradual worsening of the problem over a period. Buy a now very inexpensive infra red temp detector and see if you have any areas that are cold, probably blocked, try flushing.

The primary function of the rad is to exchange heat from water to air, by far the most common problem in my limited experience is the front of the rad being blocked with flies etc and in a dry dusty environment just common build up of dust. Nobody ever looks at the front of a TVR crossflow rad, its hidden under the spare wheel! If air isnt passing through its not exchanging heat to air. Try GENTLY blowing with an airline from the back to the front of the rad, You will probably be amazed what coes out and thats all stopping air flow. If the cooling fins of the rad come out too then that indicates the next point about the state of the core. The ambient temp really is not that important, its the difference between the water temp and the air and with water at 88 degres and air at 35 there is a sufficient temperature gradient for effective cooling. The next commonest failing is the contact and therefore the efficiency between the cooling tubes of the rad and the cooling fins. Check if they are loose, if they are they wont be efficient.

Check your anti freeze strength and your ignition timing.

If its none of the above the blame global warming, something we need in UK right now, bring back leaded petrol.

ps the infra red temp detector is a VERY useful tool, can be used to measure brake temps, so detecting binding, wrong pad material etc, exhaust temps so helping find missfires and lots of uses around the house. Buy your wife one for her birthday.



Edited by thegamekeeper on Tuesday 31st July 18:09
The other thing to add..Before you do any of the above...and only if it has been OK at all other times....Check your thermostat...
It seems to me however that you feel your problem has become worse after doing work to your car and removing the shrouding...put it back!!

N.


Edited by heightswitch on Tuesday 31st July 18:28

thegamekeeper

2,282 posts

304 months

Tuesday 31st July 2012
quotequote all
heightswitch said:
thegamekeeper said:
nForget about "latest cooling updates" whatever they may be (no doubt we will soon find out). You dont say if the temp rises when you are moving or staionary so I,ll assume its while you are moving. It will certainly be the last of the 3 2500M cooling systems so other than upgrades to more modern materials, fans etc there should be no fundamental problem with what you have if its working properly and in good condition, its been OK for the last 35 years .

There are only 2 fundamental reasons temperature of cooling system rises above what it has normally been running at 1) More heat into system 2) less heat out.

Usually more heat in is a result of leaking head gasket, and as the car runs hotter then a failing gasket will get weaker and the ehgine will get hotter and the gasket will fail. Have the cooling system pressure tested to diagnose or eliminate.

Less heat out is more likely. People assume that because there is no water leaking from rad its ok. If its been in there a while several things can affect its performance, sludging up being the most likely so only a percentage of the radiator is cooling the water hence the gradual worsening of the problem over a period. Buy a now very inexpensive infra red temp detector and see if you have any areas that are cold, probably blocked, try flushing.

The primary function of the rad is to exchange heat from water to air, by far the most common problem in my limited experience is the front of the rad being blocked with flies etc and in a dry dusty environment just common build up of dust. Nobody ever looks at the front of a TVR crossflow rad, its hidden under the spare wheel! If air isnt passing through its not exchanging heat to air. Try GENTLY blowing with an airline from the back to the front of the rad, You will probably be amazed what coes out and thats all stopping air flow. If the cooling fins of the rad come out too then that indicates the next point about the state of the core. The ambient temp really is not that important, its the difference between the water temp and the air and with water at 88 degres and air at 35 there is a sufficient temperature gradient for effective cooling. The next commonest failing is the contact and therefore the efficiency between the cooling tubes of the rad and the cooling fins. Check if they are loose, if they are they wont be efficient.

Check your anti freeze strength and your ignition timing.

If its none of the above the blame global warming, something we need in UK right now, bring back leaded petrol.

ps the infra red temp detector is a VERY useful tool, can be used to measure brake temps, so detecting binding, wrong pad material etc, exhaust temps so helping find missfires and lots of uses around the house. Buy your wife one for her birthday.



Edited by thegamekeeper on Tuesday 31st July 18:09
The other thing to add..Before you do any of the above...and only if it has been OK at all other times....Check your thermostat...

N.
Good point but the magic infra red tool will detect that. Just having a closer look at you pics the top RHS of the rad , the most crucial part where the top hose goes in looks in poor condition, you have an OGT core which is the best copper core you can have but its starting to look a bit second hand

the other tim

136 posts

169 months

Tuesday 31st July 2012
quotequote all
It's also checking the water pump, impellers have been known to rust away, fall off or break up depending on material. Worth bearing in mind most temperature guages are sensed in the cylinder head, the above mentioned heat sensing gun would give a better idea as to what's going on.

baldies

29 posts

287 months

Tuesday 31st July 2012
quotequote all
In addition to my earlier post, thermostat is being replaced this weekend, then the whole system will have been replaced in last 12 months.
Adrian recommended the non-contact infra red temp measurement device as very useful, Maplin do 2 different types: pen @£25 N62LK, or gun type @£30 N75KH.
MikeS

Slow M

2,862 posts

228 months

Wednesday 1st August 2012
quotequote all
1000 pardons. I didn't read your post carefully. Reinstall the shroud.

jastx

Original Poster:

147 posts

176 months

Wednesday 1st August 2012
quotequote all
Thanks for the advice. I will pick up a heat sensing gun, reinstall the shroud, make certain the pusher fan is actually "pushing" and check all apsects of the cooling sytem.

I should have mentioned, I have only driven this car about 15 miles since I bought it over a year ago -- about 10 of those was one short trip to a friend's when I discovered the cooling issue. So, I have no baseline for how it runs, except from the mechanics in California I spoke with when I bought it. The car has only 4,400 miles on it, original owner. It's all there, it looks excellent. It has all the receipts and was gone over completely in 2008, including a new radiator, cooling system flush and temp sensor, tranny and diff service, brakes, clutch, fuel and water hoses, plugs, points, wires -- many other things to bring it out of hibernation. It was a rare find, also White just like my '74 2500M, so I had to buy it even though I really had no time for it then.

Unfortunately, it has a few issues I wasn't expecting. None serious compared to what you guys do with your cars, but frustrating. I can't drive it and get it inspected until I fix them and I haven't had the time with other responsibilities. Aside from the cooling issue, the engine runs poorly - one carb appears to have a stuck needle valve. I bought the best recommended rebuild kits and will rebuild them both again with good parts. The shocks and springs are original so are also shot. There are several minor electrical gremlins as well.

I want to get it starting and running well without overheating (don't we all!) so I can drive and enjoy it. I don't know the details of working on this car. I need to understand the cooling system component by component so I can check each one and know what I'm looking for. Some of the responses help a lot -- any advice or procedures would be appreciated. Pointing to info on the internet would also be great, like this site for rebuilding the carbs: http://www.buckeyetriumphs.org/technical/Carbs/Car...

Thanks again,

John

Grantura MKI

817 posts

180 months

Thursday 2nd August 2012
quotequote all
Might I suggest, since you have limited time/mechanical abilities that you send the carbs out to Curto in New York for a proper refurb?
Cheers,
D.idea

jastx

Original Poster:

147 posts

176 months

Friday 3rd August 2012
quotequote all
Thanks, D.

I didn't know about Curto in NY but I have seen excellent comments about Paltech, here: http://www.paltech1.com/id4.html. However, I bought the car to tinker and learn. I do have the mechanical abilties, just not the experience of doing some of these specific things. I also have some local expertise to advise and have already purchased the rebuild kits. I have to make the time, but when it's done I'll have the satisfaction of doing it myself and understanding it and will hopefully be able to pass on my experience to others like you amazing fellows do. That's the best part of forums like this...the people you get to know.

John

Slow M

2,862 posts

228 months

Friday 3rd August 2012
quotequote all
Congratulations on the car, as it's a relative novelty, to you.

Best,
B.

Grantura MKI

817 posts

180 months

Saturday 4th August 2012
quotequote all
One thing I would like you to do is remove the crap USA smog items if you do not need them for your local...no since pumping any hot air into the motor.
Cheers,
D.