Water & Oil Temps

Speedy Goomba · Post by **Speedy Goomba** » Tue Dec 07, 2004 7:48 pm

Darin,
We've had the same results as you with mine and my fellow racer's testing. Our engines are quicker and faster the colder that are ran out. My ET's will fall off if i'm hotlapping.

We tune for 140 degrees as thats typically where we run them at (bracket racing).

My friends in stock eliminator run their cars ice cold to make a fast pass, but this is accompanied with double zero weight oil.

my question, what are you guys using for gear oil in the rear?
i'm currently using 75w-90 synthetic gear oil (mines street driven as well as raced)

Darin Morgan · Post by **Darin Morgan** » Wed Dec 08, 2004 10:12 am

Rogers Performance wrote:Darin i know you are talking drag engines but in circle track we have the oil temp at 250 to 280 before we qualify and the engine water temp at about 100.After 2 laps at loudon NH our oil temp drops to 120 to 150 are you saying that if we could keep the engine water and oil temp cold it would be better.When i dyno my cicle track stuff i set the water temp at 190 and oil to 210 for the pull yes it takes a long time to get it there but i have been able to keep it with in 10 deg of doing it that way from pull to pull using moblie 1 30w and i keep my clearance tight mains .0025 rods .0018 and oil pressure dry sump 50 LBS i see my best dyno number when the oil is that hot never tryed the water colder or is this strickly all drag racing and will not relate to circle track.
MIKE

If your engine runs on alcohol this is a mute point. Is this an Alcohol engine? If so, I wouldn't even start the engine if it was under 165F. Im kidding of course. Alcohol engines are very happy at 200F. I am referring to normally aspirated gasoline burning engines only used in Drag Racing.

This really only relates to Drag racing engines. We have a unique situation in Drag Racing. long waits between rounds allow us to take measures to cool the engine down. You don't have that luxury. I don't think you could put a large enough water to air heat exchanger on that engine to get in down to 120 degrees and if you found one, it wouldn't fit in the car. Your trying to dissipate an enormous amount of BTUs over a short duration of time. .

Darin Morgan · Post by **Darin Morgan** » Wed Dec 08, 2004 10:26 am

Speedy Goomba wrote:Darin,
We've had the same results as you with mine and my fellow racer's testing. Our engines are quicker and faster the colder that are ran out. My ET's will fall off if i'm hotlapping.

We tune for 140 degrees as thats typically where we run them at (bracket racing).

My friends in stock eliminator run their cars ice cold to make a fast pass, but this is accompanied with double zero weight oil.

my question, what are you guys using for gear oil in the rear?
i'm currently using 75w-90 synthetic gear oil (mines street driven as well as raced)

We have tried some of the 40w Synthetics in the rear end and burned them up. We are back to the 75W. Our engine oil that we use in the Pro Stock engines is 005W. It like pouring alcohol in the engine. Its so thin it still shocks me that it can set up a proper hydrodynamic wedge in the bearing and carry the loads we put on them but it does. The additive packages in these oils are so complex its amazing. They have just the right balance of phosphorus and molybdenum and other assorted chemicals I am not aware of. One little tiny mistake in the formulation and they wont make power. These new Synthetics are a Mad scientist paradise. When they work they really work! Did you know that we can run our main bearings ALL YEAR! We never replace them unless there damaged and that almost never happens. We run .004 on the mains and .00375 on the rods and .002 on the wrist pins. If you tighten anything up more than that at the temps we run these things, you will fry the bearings. Someone here asked what piston to wall clearance we run. That depends on the piston design and manufacture. We use or should I say, test every manufactures piston. They all take different piston to wall clearances due to there design and metallurgy. We run CP pistons the tightest at about .007 and they seem to run the best so far.
.

rfl28 · Post by **rfl28** » Wed Dec 08, 2004 3:36 pm

darin.... would you recommend that synthetic oil in say 540-555 bbc drag race stuff? and can you say what brand you like to run?....i run my bearing clearances in the bbc stuff around .003 rods and .0035 mains...thanks , bob

Speedy Goomba · Post by **Speedy Goomba** » Thu Dec 09, 2004 12:42 pm

Thanks Darin!
This is all very interesting to me, this is the most enlightening web forum i've been on.
I'm using 5w-30 mobil 1 in my engine now, next year i might switch to 0w-20 if it does more bracket racing then street driving.
Have you had any particular oil you use with the greatest success in your lower RPM bracket engines? (super series engines).
I may do some testing with similar weight royal purple, redline and mobil 1 this season if the time allows.

thanks!

ChrisU · Post by **ChrisU** » Thu Dec 09, 2004 1:01 pm

Darin,

How is the wear on the wrist pins with that much clearance? Is that clearance due to the high vacuum?

I run about 20" of vacuum, but wp clearance at around .008-.001 and just have not been happy with the wear charactoristics. I tried Casidium coated pins this year, aluminum rods and about 20" vacuum and the wear was no better.... same clearances, n/a comp type small block.

I was considering opening up the clearances in the wp's to around .0012-.0014 this season to see the results and now see you are running .002....

Chris

shawn · Post by **shawn** » Thu Dec 09, 2004 3:10 pm

Chris,
Are you running a piston with forced pin oilers in them?
Shawn

ChrisU · Post by **ChrisU** » Thu Dec 09, 2004 3:15 pm

YEah the pistons have the oilers, and the rod has an oil hole on top and GRP puts an X in the top of the pin bore, but the bottoms of the pin bores(in the rods) just looks terrible at the end of the season...

The engine that I put the Casidium coated pins in, looked fine the prior year with only about 12" of vacuum, but this year, same engine, more vacuum, same clearances the casidium coating seemed to be a waste... didn't help stop the galling.

Grocerius Maximus · Post by **Grocerius Maximus** » Thu Dec 09, 2004 5:12 pm

ChrisU wrote:YEah the pistons have the oilers, and the rod has an oil hole on top and GRP puts an X in the top of the pin bore, but the bottoms of the pin bores(in the rods) just looks terrible at the end of the season...

The engine that I put the Casidium coated pins in, looked fine the prior year with only about 12" of vacuum, but this year, same engine, more vacuum, same clearances the casidium coating seemed to be a waste... didn't help stop the galling.

Is it possible it isn't a lubrication failure but the pins flexing or bending?

ChrisU · Post by **ChrisU** » Thu Dec 09, 2004 6:44 pm

Wouldn't think so with a .180 wall pin but I guess it's possible. But again, same pins the previous season, same lube, same clearances and no galling with less vacuum.

RPM is about 9200 with 3.75 stroke so the piston has some speed.... The new pins will be .990, as opposed to the .927's it had. We'll see if that along with some clearance helps.

Guest · Post by **Guest** » Thu Dec 09, 2004 9:47 pm

Chris, did you see significant power gains going from 12 to 20 inches? I guess it must be worth the extra trouble, but not if it only pays off in a couple horsepower.

learner · Post by **learner** » Fri Dec 10, 2004 11:47 am

I think your going to find that your going to have to use a rod with a pressure fed pin from the crank pin on an application with that much vacuum.

Tryeverything · Post by **Tryeverything** » Sat Apr 30, 2005 11:50 am

Hi Darin, We are currently working with a 632 BBC with Big Chief heads for the 1/4 mile drags and are trying different engine temperatures for our burnouts and launches due to very strong opinions. As we start this engine we have zero valve lash. After allowing heat soak in the engine we set the valves at near 160 degrees and adjust to .025 on both intake and exhaust as per our engine builders specs. He is well known and has credibility. When starting this engine cold we experience occasional carburetor fires and sour running until 150 degrees. When it hits this temp, HANG ON. Our adjusted altitude stays roughly at 7500 feet and at under 150 degrees has a hard time with the burnout. With a single four barrel, powerglide, and over 2300 lbs. we run 8.0's @ 168 mph. Any thoughts or feelings would be greatly appreciated. MIKE

Joe Airflow · Post by **Joe Airflow** » Sat Apr 30, 2005 7:39 pm

Chris, it sounds like your pins are ovalizing and galling the pin bores. Have you tried opening up the clearances? .002 used to sound like a lot, but if that's what it takes to keep the pins from burning up then it becomes a necessity. We have been using .002" in high hp engines especially bigger bore engines where cylinder pressure becomes more critical. in heavy nitrous engines we have even gone .0025" and used heavier pins. As far as water / oil temps go, you will have to try them at whatever temps you will see at the track. run the engines as cold as you can and tune accordingly and you will always make more power. Drag stuff we can run them ice cold (ambient), but the circle track stuff is impossible to keep cold. The trends have been to use the biggest radiators you can. even the prostock / comp stuff have been getting pretty big. Some look like they pulled the rad out of the tow rig they're so big!
Joe.

Robert Kane · Post by **Robert Kane** » Sat Apr 30, 2005 7:48 pm

Darin, I am curious what side clearances on the rods do you use? With .00375" on the rods do you get a lot of oil on the cylinders?
also are the clearances different between forged alum rods and the billet ones?
and one more question, has anyone tried putting an oil feed hole in the area between the oil and 2nd rind with a feed to the pin bore to use pan vac to pull oil scraped by the 2nd through to the pin?

Don Terrill’s Speed-Talk

Water & Oil Temps

Engine temp vs valve lash etc.