need suggestions for drag racing...

[FastFox]

hey all...

I have a small block Ford set up for drag racing and am looking for suggestions for what oil to run...

I would prefer to stay away from $15/qt Royal Purple, $20/qt Mobil1 Racing, etc... The engine has a wet sump oiling system and takes 10 quarts per oil change.

The engine is set up with .0023 rod bearing clearance and .0024 main bearing clearance. Piston to wall clearance is .0085, as suggested by the piston manufacturer.

This is a naturally aspirated 355 cubic inch engine with a hydraulic roller cam in front of a three speed automatic. I shift at 8400 rpm and cross the stripe at 8700 rpm.

The engine is "chilled" between rounds down to ~50*. Water temp after a pass is usually ~130*.

I have been leaning towards Lucas Pro Stock 0-20 oil but is only available mail order.

I have also considered Mobil1 5w-20 with a bottle of ZDDPlus. This would be the most economical solution and also the easiest to obtain from the local Walmart.

Any and all suggestions are appreciated...

 

[MrMeeks]

A Petro. based 5w-20 and the zddplus additive will do well.

 

[jmaster]

do you want to run "synthetic, blend or conventional?

does it have to be a X-W20 oil? i would run a thicker oil especially in a race application.

how much do you want to spend per quart?

 

[MrMeeks]

THe piston fit seems very loose to me.
Maybe a 5w-20 is too thin for the loose piston fit.
Will this engine use a thermostat? an engine cannot produce max. power if it's operating temp. is too low.

 

[The_Eric]

Originally Posted By: MrMeeks
THe piston fit seems very loose to me.
Maybe a 5w-20 is too thin for the loose piston fit.
Will this engine use a thermostat? an engine cannot produce max. power if it's operating temp. is too low.


When a the piston manufacturer says .0085, that's what you do. They've got the R&D to back it up. Clearances that big suggest they're a forging, not a casting which would require a more normal spec. Forging will grow and move more than a casting, thus the need for more clearance.

I too would stay away from run of the mill 20 grade oils and their lower HTHS. You really don't need lots of zinc with a hyd. roller cam. If fuel dilution is an oil (causing you to change oil more often), stick with a 30 or 40 grade dino. If you've got your tune really sorted out, give M1 0w-40 a try.

A side note: If you haven't already, you may want to consult the piston manufacturer about flogging that engine with such low coolant temps. If the engine (pistons) are too cool, they could have a tendency to rock in the bore since they may not be fully expanded. Rocking pistons could lead to poorer ring seal and collapsed skirts.

 

[FastFox]

Thanks for the replies fellas...

I too was concerned with the piston to wall clearances... The pistons are 2618 forgings and are custom units from Diamond. The bore was actually done first and that is the clearance Diamond specified and made the pistons for...

Running the engine as cold as I do is worth approximately .08 to .1 in ET. I race in a heads up class so I need every advantage possible.

I would prefer a synthetic oil so it will stay thin at the colder temps.

The carb is square jetted with no power valves so it does have a tendency to dilute the oil. We have a rule that does not allow us to tow the car to the lanes or from the scales. I usually change the oil every 10-12 passes.

Prior to "chilling" the engine between rounds I ran Brad Penn 10w-30. It seemed to do Ok as I did not have any oil related failures. We are trying to get our program to the "next level" and are now focusing on all of the "little details". You know, the ones that are only worth 1 or 2hp...

Some of the folks in my class are running the Lucas Pro Stock 0-10, Royal Purple XPR and Joe Gibbs XP1. The fella that won the points for the year, however, does run Mobil 1 0-40...

If you all have any more suggestions I really appreciate it...

 

[buster]

M1 0w40

 

[The_Eric]

If you are intent on a 10 or 20 grade oil, you'd better do some talking with Amsoil, Redline or Royal Purple. To be honest, I don't know how well an over the counter 20 grade oil will take care of your engine. Also, in the interest of cost savings and engine life, you should consider sending some samples of your oil out for analysis. This may allow you stretch your drain intervals with no ill affect on your mill...

 

[Hemi426]

Drag racers usually change oil too often to justify the cost of synthetics. A lot of the drag racers around here use Brad Penn Penn Grade 1 race oils. It comes in many viscosities, has a lot of zinc and phosphorous, and some is synthetic or semi-synthetic. Check out www.bradpennracing to see what they offer.

 

[SteveSRT8]

The pistons get hot before he's staged, no matter the coolant temp.

Seriously, look at Amsoil's Dominator oil. It's being used by a few real racers and it is exceptional.

 

[FastFox]

Last night I spoke to a buddy of mine that builds engines for some circle track folks including an ARCA car and several Super Late Models on what oil they run in their engines...

He stated that one guy that runs a Super Late Model has tried Royal Purple XPR, Gibbs, Redline and Amsoil. He said there were no improvements on lap times compared to "off the shelf" Mobil 1 10w-30 from Walmart. He did say they noticed the engine ran cooler with the Mobil 1 by about five degrees in the summer. He also stated when he goes through the engines during the year the bearings look perfect and are normally put back in and used again...

He went on to say that unless one is using a flat tappet cam the high zddp oil is not needed. He stated the most important thing in selecting an oil for a race engine is that the viscosity is correct for the bearing temp. He suggested putting a temp sensor in the pan so that I could see the oil temp and then he could make a suggestion on what viscosity to run...

 

[punisher]

Just one of those situations where it's easy to overthink and overspend on a non problem.

Normally aspirated, always cool oil, 9qt pan, fuel dilution, no alcohol?, nothing too exotic................run the cheapest oil you can "afford" and err on the side of changing it more often than you think you need to.

Now, to define "afford". Afford refers to the cost of an exotic/expensive oil vs HP gain and the time it saves you at the end of the 1/4. You might gain a couple HP using a thinner expensive boutique oil, and in a perfect world that will lead to a quicker time. If that fraction of time is what you needed to get to another round, and a bigger payday, and there is no cheaper way to get that time, it might be worth it to shell out the cash for the high priced lube.