TR2/3/3A TR3 Oil Cooler Question

[Deleted member 451]

I took a nice long road trip this weekend across Florida just over 400 miles total. After about an hour on the highway the oil pressure finally settled in at about 45psi at 2800rpm. This was in 80 degree weather on a sunny day. I have never given much thought to oil cooling as most of my driving tends to be around town or within 20-30 miles, but my wife enjoyed the trip so much shy thinks we need to drive it to Key West this summer. This would be about 350 miles one way and the weather would be around 90. I have no water cooling problems it runs right at 185 when moving and I have dual electric fans (one pusher one puller) that takes good care of it at stoplights in city traffic. I use the electric fans because I converted to rack and pinion steering about 4 years ago.
My question is; Where would be the best place to mount an oil cooler and how big should it be. What problems am I going to face?
Thanks for any help you can give.

 

[Alan_Myers]

Hi Bill,

If you have no cooling problems, an oil cooler might not be necessary.

If oil pressure is down (45 psi might be slightly on the low side) I'd first want to ask what oil you are using... 20W50? If so, reduced oil pressure is most likely due to some wear in the bearing surfaces, likely the mains and/or conrod big end bearings are the culprits because these have the most surface area. Simply renewing those bearing shells may be a better way to bring pressure back up. Before digging into that project, though, check the oil pressure with a second gauge to be certain you are getting accurate readings.

And, before commiting to installing an oil cooler, I'd suggest you install a gauge to monitor oil temp closely under various conditions. It should be a bit higher than the coolant temps you are seeing, probably in the range of 200-250F. Oils are designed to operate in this heat range. Overly-cooled oil can be as damaging as over-heated. Too-cool oil will give less lubrication to bearing surfaces and will not "cook off" engine impurities as well. This latter can lead to sludge in the engine and other problems. With over-heated oil the problems are also lack of lubrication due to thinning and much faster degradation of the oil.

Also keep in mind that the old coolant temp gauge might not be all that accurate. Have you double checked it lately?

However, it's true that in very hard driving situations TR2/3/4 can overheat oil and a cooler might be desirable. After checking the things listed above you might still want to install one, and there are several ways to do so.

Probably the easiest method is to just mount the oil cooler right against the front of the radiator. Done right, it won't rob much, if any, cooling effect from the radiator. It's important to keep the oil cooler right up against the front of the radiatior, not a few inches ahead of it. If there is a gap of one or two inches between the two, that can set up air turbulence that actually reduces the flow through the radiator, something to be avoided.

It's possible to mount the cooler elsewhere, hopefully some other TR3 owners will jump in with some suggestions.

On my TR4 it's getting mounted on the valance with it's own intake (similar to what's on TR250/5/6). Mounting on the valance moves it far enough forward of the radiator that I don't think it will cuase any problems with radiator air flow, plus it's an added air intake, increasing flow to both. One possible problem with valanve mounting is that the cooler is more vulnerable up front. It also needs longer hoses to reach that far.

A third common installation is inside the engine compartment, vertically oriented right next to the radiator, and with some air ducts cut through the rad shrouding to redirect some air to the cooler (for racing, some cars instead position it behind a headlight, which is left out to create an intake duct).

I think it's a bit of a tradeoff, though, whether to take some air flow away from the radiator and redirect it to an oil cooler *or* to flow the air through the cooler and then into the radiator.

Probably an adequate size oil cooler for most street TRs is a 10-row. That's what was used in the TR3 racers, once coolers were permitted. A 13-row is often what's sold by the Triumph vendors and can be used in slightly more demanding situations and/or if the engine has performance mods that generate more heat (increased compression, ofr example). A 16-row is about the largest size that might be needed on a TR. Mocal's oil coolers in these sizes happen to be almost the same width as the TR2/3/4 radiator, so are pretty easy to install using the first method mentioned above.

With any cooler, be sure to install an oil thermostat. That will help prevent over-cooling oil and the oil come up to operating temps faster. Mocal makes one now that's integral with a generic take-off sandwich plate at the oil filter. It's fully open at 185F. There are other types that go inline, but mean making 4 additional hose connections (adding to the cost of fitting and increasing the potential for leaks).

In order to install an oil cooler on a TR 4-cyl., it's common to convert to a spin-off filter first. This provides a place to put the generic sandwich plate with ports for the oil cooler hoses. Another approach is a specially made sandwich plate that goes under the TR's filter head itself. Greg Solow at the Engien Room in Santa Cruz California is the only source I know of for this type.

One concern with an oil cooler is that the routing of the oil send it to the oil filter first, then on to the cooler before being returned to the engine. This helps prevent normal engine particulates from gradlually fouling the cooler, and also helps protect it against high pressure spikes.

Besides the usual cooler, there are some other approaches to cooling the oil in a TR. One is to simply enlarge the sump pan capacity by welding on additions. The extra oil and oil sump pan surface area will do a lot to improve cooling.

Another is to install tubes through the length of the oil sump pan itself, that will allow extra air to pass through. This has the benefit of being a "passive" improvement, no moving parts to go wrong or extra plumbing connections to leak. However, there is also no way effective way to control the cooling... i.e., no thermostat... and by itself this will reduce the total volume of oil in the engine a bit. (Might be better done in conjunction with increasing the pan's capacity.)

Yet another possibility is to add an Accusump (or similar) instead. This is an accumulator for oil, which is kept under pressure and "injected" into the oiling system at startup and, say, during hard cornering if the oil pump pickup is uncovered and sucking air instead of oil. An Accusump gives an extra measure of protection. There are both manual and automatic models of these. The extra oil capacity and storage of oil in an external container will help keep oil temps under control a bit, too, although this isn't the primary purpose.

There are a few possible downsides to an oil cooler. One I've already alluded to is contamination. It's practically impossible to clean out an oil cooler and over time it will gradually get fouiled with particulates from normal engine wear. So it should be protected by filtration "upstream" and might need to be replaced every so often, perhaps every 25,000, 50,000 or 75,000 miles depending upon how the car is driven, if there is any bearing failure, etc.

Another possible concern is that it's difficult to get a complete drain and change of oil when a cooler is installed. Invariably, some oil is trapped in the lines and cooler. This can be quite alot, depending upon how the cooler is installed and how the plumbing lines are run.

Each and every plumbing connections is a potential source of leaks, and the cooler itself can be damaged by a flying rock or similar with more catastrophic results, or can even be damaged by unusually high oil pressure.

There is also a lot of cost involved with the hoses and fittings. I prefer to make up my own stainless steel braided lines and I don't really trust the normally cheaper rubber hoses (which probably were used for original installations). Doing this, you'll be using AN10 or AN12 sizes, and some of those bigger hose ends go for $25 apiece! It adds up fast!

One thing to watch out for, many of the Triumph vendors sell coolers with British pipe thread fittings, as were originally used. In the US it's harder to find hose ends to fit these, so you might choose a cooler that's got more common AN fittings instead. I've found https://www.racerpartswholesale.com to have good prices and selection of coolers, thermostats and adapter plates. https://www.summitracing.com or https://www.jegs.com are good sources of the hoses and fittings.

Oh, by the way, in my opinion you might be best served by removing the pusher fan entirely and only using the puller. A pusher fan will in many cases partially block air flow. A puller fan is more efficient. Plus, removing the pusher fan will make more room for an oil cooler if you decide to mount it directly in front of the radiator.

 

[Guest]

Bill, rather than add an oil cooler onto an already crowded area, why not consider changing your electric fans to electric fan. I would consider using the largest puller fan you can get, perhaps a 16" model. An even more adventurous possibility would be to go to an aluminum radiator and a Spal fan with shroud. Check out Ron Davis Racing. They will build you a new aluminum radiator with a shrouded Spal fan custom fitted to that radiator. (assuming you no longer have a crank fan.) The Spal-brand fan is top quality and is designed to run almost continuously, not that that would be necessary. The shroud would enclose the uncovered area of the back of the radiator and better direct your air flow. A stock TR3 with proper cooling should not need an oil cooler. Just change your oil every 2000 miles. I ran my TR3 all over creation for years and never had heating issues, except when the ice melted and my beer got too hot.

 

[YankeeTR]

A puller fan is much more efficient than a pusher..the pusher does block air flow in many cases.

 

[fad64b]

I to have noticed this same condition with my TR3 oil pressure starts out 65 to 70 psi but on long rides on hot days engine temp is normal but the pressure tends to fall.

It has been suggested to try an oil cooler they are used on the MGB but I still can't figure where to install it. Here is another link for radiators.

https://www.cooledbyice.com/index.html

 

[prb51]

Depends on where you live. I'm putting a cooler on this summer as in Az. it overwhelms the oil. My car will run 185 degrees and the oil pressure always normal in normal weather but in 100+ degrees the oil thins.
If your car runs 185 then an additional elec. fan will not help that although in the 80' low 90's my car's oil pressure stays high.
Others in the Phoenix club have mounted the cooler below the lower rad opening after cutting an opening there. I will do this as I have a 56 small mouth and there is no room behind the valance bodywork and radiator. A TR3a may have enough room for the mounting in front of the radiator.
This fixes the oil viscosity issue and the pressure in extreme heat.

 

[Andrew Mace]

Advice given by Alan and others seems great, but frankly I just don't see a problem based on the information given. If you're not using a good 20W-50 oil, by all means switch to it for the hot temperatures. Meanwhile, 45 psi at speed when hot isn't exactly low oil pressure. 10-15 psi WOULD BE.

 

[JFS]

I mounted an oil cooler vertically against the right hand side of the radiator. I made an aluminum shroud to fit. The engine is modified, and I had problems with overheating. I fitted a puller fan behind the radiator. I punched louvers into the bonnet. And then I removed the oil cooler because the engine frequently ran too cool here in Wisconsin; however, I have driven it in 90 - 100 degree temps without the cooler without any overheating issues. The cooler really isn't necessary on a street car in the midwest, IMHO. Definitely use a thermostat if you do use the cooler, and be sure not to let anything rub against its ss hoses -- they'll chew it apart.

 

[Alan_Myers]

I mounted an oil cooler vertically against the right hand side of the radiator. I made an aluminum shroud to fit. The engine is modified, and I had problems with overheating

So, your experiences confirm that vertical cooler mounting and "robbing" some of the radiator's airflow might cause problems.

and be sure not to let anything rub against its ss hoses -- they'll chew it apart.

Quite true!

There are a few relatively possible solutions to that, though.

One is to wrap the s/s hose with coiled "wire wrap" that comes in various colors and sizes. The plastic wrap helps protect anything the hoses might rub against.

Also, some rubber lined clamps can be used to fasten the hoses various places, to help prevent abbrasion.

Finally, there is a relatively new type of hose being made that can help: Earl's Performance Pro-Lite 350 is available at https://www.summitracing.com (probably others like https://www.jegs.com too). This particular hose uses a black, nylon braided exterior covering, rather than stainless steel. It's lighter weight, too. Tends to be a bit more expensive than the stainless steel stuff, though, and needs to be used with special fittings. But, it might solve the problems and is said to be tough stuff. (I've not used it yet, but might do so when I revise my cooler mounting and will need longer hoses.)

I punched louvers into the bonnet.

That's another good point. In the quest for additional cooling, it's sometimes overlooked that giving the hot air an easy route *out* of the engine compartment will also help alot. Air flow gets somewhat trapped in the engine compartment, with the driveshaft tunnel being the most likely exit (adding to cockpit temps, too). The higher your cruising speed the more this "damming up" of air inside the engine compartment is likely to have some effect on how much air can be pulled in through the radiator.

Some sort of air outlet is less easily done on TR2/3 than on TR4/250/5/6, where fender vents can be fairly easily installed. On the earlier cars, hood louvers like you used are probably the most common solution (just keep them clear of the ignition, to help prevent rain getting in and causing problems!). A bank of rear opening, inverted louvers across the hood right behind the radiator might be used to allow air out well there. Another set of rear-facing louvers nearer the rear edge of the hood can vent that area.

A couple possible concerns with louvers: At speed pressure from the windshield can cause air to enter the louvers, instead of exiting. So, louvers should be placed to close to the windshield. Also with louvers any catastrophic oil leak from the engine might spray a lot of hot oil out onto the windshield, something anyone racing with a Brooklands or other type of shorty windshield, especially, might want to think about!

 

[Jim Lee]

Hi JFS,

I am just wondering what temperature you considered too cool if it was on your tr3? I have been seeing some much lower temperature since recoring my radiator and was curious what you did to raise the temp if you did.

I am in North Carolina and my temperature gets just a few degrees past the tick mark BEFORE what I assume is the 'normal' 6 o'clock needle reading of 185. It does get up to 185 after I turn off the car after a run. Did you have any specific poor running symptoms when it was running too cold.

Thanks very much,
Jim Lee

 

[JFS]

So, your experiences confirm that vertical cooler mounting and "robbing" some of the radiator's airflow might cause problems.

After rereading my previous post, I see that I didn't say what I wanted to say. Mounting the cooler vertically alongside the radiator, not in front and to the side of it, did not rob the radiator's airflow at all. I found this vertical mounting an excellent way to add the cooler to a wide mouth TR3A, but hoses supplied may not be long enough if you buy a kit. The third sentence about the engine being modified should have been the first sentence of the post.

I fitted the cooler, installed my shroud, fitted the puller fan and punched the louvers all at the same time -- about 15 years ago. The result was overkill, so I removed the cooler and the engine has been running at normal temp all these years.

I am just wondering what temperature you considered too cool if it was on your tr3? I have been seeing some much lower temperature since recoring my radiator and was curious what you did to raise the temp if you did.

During the cooler months on a longer drive outside of the city the temp would fall well below 185 normal -- I do not recall actual temps, but I felt uncomfortable driving long periods of time with the lower temps. The engine also took a lot longer to warm up after start up. The engine seemed to run well enough at the lower temps; my concern was for unnecessary wear. Pulling the grill to cover and uncover the cooler did not seem like a viable solution. Modified engines usually need some rebuilding sooner than stock engines and during the 20yrs that I've been running it, I've only had to rebuild the head about four years ago. Pulling the grill to cover and uncover the cooler did not seem like a viable solution. To raise the temp, I simply removed the oil cooler.

 

[prb51]

Are the gentlemen running oil coolers that allow the engine to run too cool using thermostats with the oil coolers. I would think an oil cooler/thermostat set up would negate the 'too cool' issue by system shutdown.
I also agree that 45psi isn't really a problem.
Where have the TR3 small mouth guys mounted their oil coolers? I don't think there is a location anywhere but below the radiator opening with a panel cut out.

 

[JFS]

Are the gentlemen running oil coolers that allow the engine to run too cool using thermostats with the oil coolers. I would think an oil cooler/thermostat set up would negate the 'too cool' issue by system shutdown.

No, I did not run an oil cooler thermostat. In retrospect, the thermostat would have been a viable solution; however, I really didn't need the cooler so I think its removal was the better solution -- but perhaps not for a TR3 living in Arizona.

 

[prb51]

Yea, I don't do a great deal of city driving as I'm in the country but many live in Phoenix proper and 110 sitting at a traffic light can push things a tad. Cars in great condition experience the oil thinning/drop in pressure with fresh 20-50.
The oil cooler has fixed this issue for those that have tried it but everyone runs a thermostat to allow for proper running temp at start up and in cooler weather.

 

[Guest]

If one does decide to go with an oil cooler, consider the below mounting configuration as an alternative to simply bolting it on. These coolers are all made out of aluminum and because they all seem to just be bolted to something, they vibrate, and they crack. I have a friend that dropped his whole oil pan load of oil because the poorly mounted oil cooler cracked. His good fortune is that it happened in his driveway and he was able to save his engine. This mounting hardware came from Earl's Fittings, somewhere on the web, and is put together with stainless all-thread and fasteners and I guarantee you it does not vibrate. (I have posted this before but wanted to emphasize the seriousness of loosing one's oil.)