quote:

Originally posted by TD3550:
.0030/.0035. After 400 hits on the 598 steel rod and 300 on the 632 steel rod. (L19) only. Good billet pump. AND only RP XPR 20/50 full synthetic.
Q16 fuel... Send it. I have better things to do than beat a dead horse on spec clearances. Like go have a beer.

quote:

Originally posted by NortonRacing:
I would be curious to see how much HP you would pick up on a serious bracket engine when going to light weight oil and smaller bearing clearances. On some NA stock head 4 cylinder stuff I have seen over 5% gains but we are talking 200 HP total. NASCAR and Pro Stock have been running 0 weight stuff for years so its not thar it cant be done.

Personally I feel like tighter clearances and low weight oil get a bad reputation from people who have not done a lot of research. You actually lose load bearing capacity at high clearance in relation to the oil weight being used. Small clearances and heavy weight oil will typically over heat the bearing before failing.

So did tight clearances cause the failure or improper oil?

Factory spec for LS1 main clearance is .0007 to .0021, you see 800+ hp stock bottom ends all the time. When they fail its usually a major parts failure and not bearing related so what's that story tell?

quote:

Originally posted by NortonRacing:
I would be curious to see how much HP you would pick up on a serious bracket engine when going to light weight oil and smaller bearing clearances. On some NA stock head 4 cylinder stuff I have seen over 5% gains but we are talking 200 HP total. NASCAR and Pro Stock have been running 0 weight stuff for years so its not thar it cant be done.

Personally I feel like tighter clearances and low weight oil get a bad reputation from people who have not done a lot of research. You actually lose load bearing capacity at high clearance in relation to the oil weight being used. Small clearances and heavy weight oil will typically over heat the bearing before failing.

So did tight clearances cause the failure or improper oil?

Factory spec for LS1 main clearance is .0007 to .0021, you see 800+ hp stock bottom ends all the time. When they fail its usually a major parts failure and not bearing related so what's that story tell?

quote:

Anything is possible but that story is pretty hard to believe to be honest especially coming from one of the most experienced and famous teams of all time.

quote:

Originally posted by SCDIV1:

quote:

Originally posted by NortonRacing:
I would be curious to see how much HP you would pick up on a serious bracket engine when going to light weight oil and smaller bearing clearances. On some NA stock head 4 cylinder stuff I have seen over 5% gains but we are talking 200 HP total. NASCAR and Pro Stock have been running 0 weight stuff for years so its not thar it cant be done.

Personally I feel like tighter clearances and low weight oil get a bad reputation from people who have not done a lot of research. You actually lose load bearing capacity at high clearance in relation to the oil weight being used. Small clearances and heavy weight oil will typically over heat the bearing before failing.

So did tight clearances cause the failure or improper oil?

Factory spec for LS1 main clearance is .0007 to .0021, you see 800+ hp stock bottom ends all the time. When they fail its usually a major parts failure and not bearing related so what's that story tell?

Pro Stock cars are towed to the lanes, everything is controlled from water temp to oil temp and they run dry sumps...

NASCAR I can't say for sure but I doubt they run zero weight oil for a full race in hot conditions.....
Qualifying, yea sure maybe but not depending on what their rules dictate. If you hurt an engine during qualifying and have to replace it there usually was a penalty.....you start in the back no matter where you qualified..

I know many Stocker guys that might drain some oil and use thin oil if they have a heads up and it sometimes ends up roasting a bottom end.....

You can't win if you don't finish and a few HP means very little in most categories the way we race....

As an engine builder, you cannot afford to take chances with customer engines......you go with what works best and unless you spent the time and $$ to test your changes for reliability you don't chance it.

NASCAR- PRO STOCK and other high end race venues with big budgets can explore it all

I have no doubt whatsoever tighter clearanced engines and thinner oils can live and do....but I'm not going there.....

quote:

Originally posted by 1320racer:
No reason too, these are bracket engines engineered to go hundreds of passes with nothing more than oil changes and the occasional lash check.

That said, Rich built my engines from 1999 to 2008 without issue and my 11:1 cast iron oval port headed 468 in my Chevelle couldn’t be touched by similar engines in similar yet lighter cars with more, compression, cam, heads and carbs.

quote:

Originally posted by 1320racer:
No reason too, these are bracket engines engineered to go hundreds of passes with nothing more than oil changes and the occasional lash check.

quote:

Originally posted by SCDIV1:
R-M and other GM teams ran 366 cube BB's back in the weight to cubic inch era

They used 409 cranks once Reher and some others discovered that would work in a 427 block

The Honda journal size came later down the road and probably trickled down from NASCAR as they developed their 358's...

They welded a ton of material on GM aluminum heads on the decks so as to be able to angle mill the heck out of them and roll the heads over....

I saw lots of things come thru the shop I worked at going back to the late 1970's and into the 1980's

I saw small block iron heads with intake ports so large I could not really tell how they got that big !! Plenty of epoxy....

quote:

Originally posted by Yellow Ticket:

quote:

Originally posted by 1320racer:
No reason too, these are bracket engines engineered to go hundreds of passes with nothing more than oil changes and the occasional lash check.

No Kidding, but some people still think everyone cares how much someone can do with so little. Give me low maintenance over .05 for this style of racing.

quote:

Originally posted by TD3550:

quote:

Originally posted by SCDIV1:
R-M and other GM teams ran 366 cube BB's back in the weight to cubic inch era

They used 409 cranks once Reher and some others discovered that would work in a 427 block

The Honda journal size came later down the road and probably trickled down from NASCAR as they developed their 358's...

They welded a ton of material on GM aluminum heads on the decks so as to be able to angle mill the heck out of them and roll the heads over....

I saw lots of things come thru the shop I worked at going back to the late 1970's and into the 1980's

I saw small block iron heads with intake ports so large I could not really tell how they got that big !! Plenty of epoxy....

Then you had to come across Joe Mondello heads?
A friend of mine still has a set of his heads on the shelf. A lot in here don't know know who he was. Back in the days of running what they call RTE. Run Tuff Eliminator.

quote:

Originally posted by CURTIS REED:
Why is this thread even here? I thought this guy already knew everything? LOL

quote:

Originally posted by I Hate Dragsters:
There is a ton of reading discussing bearing clearances, oil viscosities, and applications.
Bearing and oil manufactures go into depth detailing the relationships, if you feel like diving in that rabbit hole.