Oil Q

[bigrob]

The previous owner told me that Keith Craft, builder of my motor, recomends using regular Castrol 10-30. He had been changing the oil every 2000 miles, which I like!! I was thinking of maybe going with M1 syn. What do you guys think?

Grazie!

[jwoodard]

Keith recommends against synthetics until after 6K miles. For my engine he spec'd Castrol 10W40, which I've been using faithfully.

[bigrob]

My motor is heading toward 13,000 miles. I am always a little skeptical about switching, but I would feel like the motor would be better protected with a synthetic.

[rsb427]

better listen to builder! synthetics get lots of praise but not long ago people found out that some oils are good for newer engines but not older ones like flat tappett cams. new oils lack the zinc needed in those high friction areas unlike newer motors which have roller cams and different metals so take oil seriously I had friends lose a flat tappett cam in less than 1,000 miles to find out they didnt use correct oil, I use dello 400 diesel oil myself in my solid lift 390 ford lots of drag racers use it to. good luck hope this sheds some light!

[bigrob]

Originally Posted by rsb427

better listen to builder! synthetics get lots of praise but not long ago people found out that some oils are good for newer engines but not older ones like flat tappett cams. new oils lack the zinc needed in those high friction areas unlike newer motors which have roller cams and different metals so take oil seriously I had friends lose a flat tappett cam in less than 1,000 miles to find out they didnt use correct oil, I use dello 400 diesel oil myself in my solid lift 390 ford lots of drag racers use it to. good luck hope this sheds some light!

You make alot of sense & I am probably gonna stay with the Castrol. I think I will feel better that way. This is always a hot & crazy topic & I've seen so many different opinions on the other 3 forums I belong to for my vehicles. It can really get your head spinning!

Thanks for the input!!

[ERA2188]

Keith said "I recommend any good 10w 40 regular oil like Castrol" just change it frequently. I am getting a couple cases of Brad Penn - great oil - high zinc level. RD

[thorconstr]

I don't know about small blocks, but if you want to develop a leak in a big block, use synthetic!

[vector1]

i drank a bunch of castr'oil one time and developed a leak. i don't think it was synthetic.

[DougR]

Rob, As far as I'm concerned there is only one rule for oil: Use what the engine builder recommends. He knows that engine better than anyone so do what he says.

Having said that, If I only drove my car on the street, I wouldn't bother with syn. I use it only because of the abuse and high temps when tracking the car.

[bigrob]

Originally Posted by DougR

Rob, As far as I'm concerned there is only one rule for oil: Use what the engine builder recommends. He knows that engine better than anyone so do what he says.

Having said that, If I only drove my car on the street, I wouldn't bother with syn. I use it only because of the abuse and high temps when tracking the car.

I appreciate the info! Thanks Doug. I am gonna stay with the Castrol!
I am wondering why everyone with a K. Craft motor has mentioned 10-40, & mine calls for 10-30? Would engine size & different build components call for a different weight?

[speed racer]

The tolerances in the bearings make the difference in oil weight. Its like ball bearings 10 weight is one size and 30 is larger and so on. the oil companies mixed them together to create 10-30 ect... remember when their was #1 and #2 oils 10 weight and 20 weight all the same size molecules. If the tolerances are to tight to high oil pressure and oil will not find its way in the small places.Not saying there is anything wrong with multi weight oil.Don't raise the gas prices again oil companies.

[vector1]

alright on a serious note. i just visited the local book store and picked up a book how to build chevy small block circle track racing engines and there is an article in there about diesel engine oils. comp cams did a lot of research on oils and flat tappet camshafts and came to the conclusion that many of the diesel engine oils have high pressure friction inhibitors as good or better than any of the previous automotive oils. oils to look for are ci-4 plus, ci-4, and cf-4. these oils should be used at least through the break-in period along with comp cams camshaft break-in lube oil additive. there is also a short list of oils such as castrol tection extra 15-40, chevron delo, delvac 1300, and shell rotella.

just something to think about fwiw. i think the oils are now in the cg to ch range so things might have changed. book copyright 2007.

[lineslinger]

Originally Posted by bigrob

Would engine size & different build components call for a different weight?

Yes, reread your specs..

[Got the Bug]

Roush recommends 10-30 and that the oil be changed every 3,000 miles or 3 months. I also run the Castrol 10-30.

Side note about oil. I know a guy who works at Honda Racing and I asked him about oil. They use off the shelf oil. The brand is driven by the sponsor, but Honda has to validate and approve the oil. Supposedly only one brand of oil didn't pass the test (starts with a Q).

[DougR]

Originally Posted by bigrob

I am wondering why everyone with a K. Craft motor has mentioned 10-40, & mine calls for 10-30? Would engine size & different build components call for a different weight?

Rob, If in doubt, place a call to K.Craft. Let them know what engine you have, serial #, build date, etc. They should be able to direct you to the proper weight oil for your engine.

[Bob In Ct]

Just for the record, you don't get 10W-30 by mixing 10 weight oil with 30 weight oil, you get something closer to 20 weight oil. Both multi-viscosity and straight weight oils get thinner as they get hotter. The multi viscosity oils (thanks to additives) just thin down less.

I'm always amazed at how many Cobra owners prefer heavier oils even though most of us have oversized crankcases and oil coolers. I know if someone came out with a 20W-70 oil There would be a rush to pour it in. I always wonder how much of the oil some guys are pumping is just going out the bypass.

Just my $0.02

Bob

[Rick Parker]

Bearing clearances at operating temperature dictate the viscosity requirements, regardless of engine make, or size. But I agree that your engine builder should be consulted.

[RodgerH]

Originally Posted by Bob In Ct

I know if someone came out with a 20W-70 oil There would be a rush to pour it in.

And here it is!

http://www.gopurepower.com/store/ite...em&itemKey=645



Rodger

[bigrob]

I have already sent an email to K. Craft on this oil weight question. I have gotten no response as of yet. I will call on Monday. I dont think the PO got this wrong, but I want be be absolutely sure!

Thanks all!