Best oil cooler and temp difference????

[Backdraft#64]

Two questions.

First, what is the best oil cooler for our cobra's under race conditions not thaking origionality into consiteration.

Second, what is your experience with your oil temp under race conditons without an oil cooler vs. with one. I am looking for a tempature differance between having an oil cooler under race conditions vs not.

[Morris]

#64

Look at the Fluidyne Oil coolers at HRP..... I think it was the sportsman model.... we had to modify to mount it to the chassis....but it will cool the best of the bunch..... very deep and lots of surface area..... we use it with a oil Thermostat and bring our oil up to 210*degrees quickly and maintain the temp.

Under racing conditions .... water needs to be at 190*-200*degrees and oil at 220*...... this is the ideal temp when running motor hard..... with a conventional cooling system....

Racing and no oil cooler is not recommended..... especially when you come up behind someone....

Morris

[Jac Mac]

#64

After having two conventional air/oil type coolers fail I converted to a water/oil heat exchanger that fits in the bottom radiator hose. This unit is virtually bullet proof and not up front in a damage prone area. Temps are in the ballpark of those in Morris post above#2.

Jac Mac

[Curt C.]

220 oil racing temp? Really? That is just hot enough to boil off condensation ect. and about what factory OEM cars run on the street. My oil temp, with an Accusump and Harris oil cooler (approx 12 quarts of oil) will run 250 - 260 after a 30 minute session on a road course (85 - 90 degree day). What am I missing?

[Morris]

Curt

You need a larger oil cooler..... if you are going to try to go faster or compete..

250*degrees to 260*degrees is on the verge of over heating and will start to coke up.....

If you were really racing and came up behind another competitor .... your motor would over heat in a matter of half of a lap.....

Ideal temps to make horsepower is 200 water and 220 oil.....

Morris

[Jac Mac]

Curt,
Or you need to find out why your oil is so hot. To large a pump which can cause the relief valve to be in operation continuously and recirculate the oil in the pump or a baffle /windage tray that is not functioning as intended.
Caught a 1/4 mile dirt car that was cooking its oil due to a scraper rail that was deflecting the oil back at the crank under acceleration[351w].

Morris is right on the money!

Jac Mac

[DAVID GAGNARD]

Wholeheartly agree with Morris on the temps..........when I was still using conventional 15/40 oil, my oil temp would peg my 240 degree gauge in 3 laps......tried 3 different coolers with about the same results, switched to synthetic oil and my oil temp has not gone past 230 now, even on a 100 degree day...........water temp stays bewteen 180 and 190..........

also noticed that anything past 230 oil temp, I would lose about 10 psi of oil pressure..........

The temps Morris quoted are the standard by which the NASCAR boys like to run, they run those temps for 500 miles at a time.........
One fellow racer told me he likes to see his oil temp anyhwere from 250 to 270 , he still can't figure out why he blows a couple of engines every year!!!!!!!!!

David

[Curt C.]

I run synthetic 15-50 oil. Engine is a 351W with approximately 450 FWHP. Pump is a high Volume Melling; Canton road race pan with trap doors. Motor is about 7 years old with 5-6 track weekends per year on it and seems to be holding up OK. I will look into the pump and bigger coolers. I thought 260 was fine and that a good synthetic could go all the way to 300.

[DAVID GAGNARD]

Curt;

My race motor makes 472 fwhp and I normally shift at 6,000rpms, with a 7,000 rpm chip in the MSD box.......I do not run a high volume pump, I run a Melling HP oil pump, it can be adjusted for the oil pressure, but is standard volume......I think high volume oil pumps are hard on the cam/distibutor gears and are not always needed.......A very well know race shop told me that they never use high volume pumps on any race motor much less a street motor, but they do like the HP model oil pumps.........

Synthetic oil can and will tolerate more heat, but after a certain temp, I'd guess over 230 or so, your oil is so hot it's not doing the job it was meant for........

My race motor is a 331 cu.in. stroker based on a 302 block using the Chevy rods, smaller journals than the ford 302.......my street car has a 351-W and the main crank journals are 3" diameter, very large and produce a lot of heat compared to the smaller 2.25" 302 main journals..... I have done some track time with the street car/351-W and have seen 240 to 250 oil temps on a 100 degree day, both motors have road race baffled pans and windage trays.....

David

[Ital-cobra]

thanks

you guy's really know your stuff..........very helpful.

Great site...

Joseph

[Curt C.]

David, thanks for the info. I am aware of the larger journals in the 351W and the HV pump generating higher temps. I just thought I was well in the safe range. Sounds like our 351W engines run comparable temps. I am going to check the temps next time with the infrared temp gun. My sender is in the pan - top of the left side kick out to be exact. It is about time for me to rebuild the motor. I am going to talk with the engine builder and install an appropriate pump as well as check the baffling ect. A larger cooler is not a problem either. Thanks all for the info.

[JBCOBRA]

Oil that is not hot enough (under 200*) is worse than 260* 280*
Oil has to be hot enough to work right. Hotter than the water, also.
So, if you are just putting around and can't get decent oil temps, get rid of the cooler because chances are you will never need it anyway.
JB

[Ant]

My Cobra has a dry sump system, with an approx 2 gallon oil tank, fitted end of passengers footwell, plus the engine is all alloy, the pump scavenge plumbing was going to incorporate a -16AN fitting 13 row oil cooler, mainly to give some cooling if necessary, and also to look like a race Cobra, and I could fit the number plate over the cooler opening to deflect air if the temperature is to low!
I would be surprised if a cooler was necessary, and if so a heat exchanger might be a better idea to get the oil to a suitable level of 190F, and I would emagine the oil could go a bit higher even though the water system is removing heat.

Another issue with this system is on startup circulating cold oil of a greater quantity, considering two 110volt inside oil tank heaters, set up in series so I can run our 230-240v power to pre heat engine oil. Sometimes I think my system is overkill and sucks $$$$$$$ but I guess try and do it once ........!

[Morris]

Ant

We've been running the Dry Sump for many years and now we are using one on KMP 259......

A thermostat would be better then a Heaters in the tank......

With the thermostat the oil temp is up to 210 with in a few minutes or a few miles......

Btw we are using 17 quarts of oil with our system and the thermostat controls the oil temp whether we are on the track or street...

And -12 Aeroquip is fine .....-16 is to big....

And the bigger concern is making sure the motor can breathe.....

Morris

[Ant]

Morris,

Tank heaters, I was thinking of cold start up, to have warm oil there straight away, and with the oil cooler air duct blocked off, would I achieve what the thermostat does?
I am using -12AN for most lines apart from, tank to oil pump, and scavenge port back to tank, I have thought these lines are monstrous, so I might adjust size, as they are harder to bend, take up more room etc.

Breathing, the oil tank has two 1/2npt ports both going to a separate breather to get rid of oil scavenge air, the penske valley cover has a -12AN fitting which will go to the breather tank, I am hoping that will be enough for a dry sump system!

[Morris]

Ant

With the oil cooler blocked off .... you will still not get the motor up to 210-220*degrees.....

Only with a Thermostat will you get the oil up to temp ....unless you are flat out on a race track.....

As far as breathing is concerned .... you are on the right track..... but you need to add another breather on the bottom end of the motor ...... like where the mech fuel pump use to be .... make up a block off plate with a -12 line going up to the breather tank..... add a check valve so it lets pressure out and not in....

Also you need the equilivant of two 1 1/4"inch breather tubes for the motor ..... if it's making lots of HP..... for the street one will do....

The original breather tanks worked well back when they were making lower HP.... but now days .... a good motor will make a lot of HP and needs a lot of breathing....

Go over to KMSAC ..... Kirkham motorsports auto club ..under forum and you'll see how we did the breather system on KMP 259..... it caused us a lot of leaks until we got the motor breathing.... and lowered the pressure in the motor...

Morris

[Backdraft#64]

Thanks for the replys

ANT I had the same thought as you with the heat exchanger VS the oil cooler.

I instaled a heat exchanger on the top radiator hose not the bottom. Prior to the heat exchanger install I did not have an oil temp gage so I do not know what temp I had under open track conditions. With the heat exchanger The oil temp comes up nicely under normal street driving 200 to 215, at the track I hit 250 to 265.

I was told it did not matter if ithe heat exchanger was instaled in the top hose or bottom hose. The top hose install was very clean without hassle.
Botton hose install could be done but would be difficult.

How much diference in temp would there be from top to bottom hose install of the heat exchanger and how much would that change oil temp?

Thanks so much for all the replys.

[Ant]

I had the oil cooler blocked off on my BBC Cobra and it made 260, at the track, unblocked it and it came back to 220.

Morris, will have a look at your website, Have looked at a lot of Muscle race cars here in NZ, some with 900bhp, they run a piddly wee breather out of one valve cover and use the scavenge to do the rest, and appear to have no problems!

Surely with the -12 out of the valley cover, and a -16 going back to the tank sucking will cover the pressure. Your recommendation to take one from the old fuel pump cover is a good idea, if I find the others not enough, or I could take one out of the valve covers (which I have just welded up the holes) you have got me thinking now!!!

Your comment about two 1 1/4" breather tubes for the motor, is this in addition to what I have mentioned I intend on doing, thats a lot of breathing?

[Ant]

Morris,

Went to your website on Kirkham Motorsports, I get the strong idea you like speed, quite a radical Cobra, what sort of HP are you running?

Car looks great, my car has similarites but I am not going to bother with spoilers etc, I have driven a Cobra at 180mph with no aids it got a wee bit light in the steering.

Re breather system, I am running a Peterson round breather which has a large gap around the circumference of the spun lid, if this isnt enough I will install another breather tank or line with filter on end from block, I am hoping my Yates Nascar based engine doesnt require as much breathing as a HP FE engine.

[Morris]

Ant

The Peterson Breather was the first breather we had on KMP 259..... it is not enough.....for hi rpm's and hp.....

The dyno showed us when you are making good HP ....then you need 2 each 1 3/8" inch breathers on the motor .......

And you need to vent the Dry Sump tank with the two -12 lines at the top running to a 1 3/8" breather just for the Dry Sump Tank.....

The pump can't keep up with the amount of air the motor is moving.....

Horsepower is something we just don't talk about.....

Lap times is all that counts....

Morris