milling the main for oil passages?

[Drift_FX]

i was looking to run theses bearings, but i have a few concerns...
Calico coated 5-Hole Main Bearing Set - Engine - Mazworx (http://www.mazworx.com/product/engine/nissan/nissan-sr20detsr20ve/engine-bearings/calico-coated-5hole-main-bearing-set)

since mine is on a det block i will have to machine out the oil passage for the other 4 holes. does anyone know the measurments for this? and wouldnt putting an oil passage under the bearing cause it to be more likely to spin due to pressure behind the bearing? or does the extra oil between the crank and bearing negate this?

i have a pretty built/high reving sr22vet (det block) and milling the main is pretty foreign territory. but im trying to make sure my bottom end can keep up with my head...

has anyone done this? and what are your opinions about this bearing setup for det blocks? also is the calico coating worth the extra $80 or is kinda a gimmick? im not to familiar with this type of coating...

[Mikester]

This doesn't answer your inquiry (probably not even remotely), but may be worth a quick review: http://zilvia.net/f/engine-tech/527208-race-bearings-food-thought.html

Interested to see input from someone who really 'knows' this stuff.

My lay question here is "Did you call Mazworx & ask them?" They are very good to their customers in terms of tech support.

subbed.

[Drift_FX]

yes i called mazworks and they didnt really anwser my question either.... however i stumbled across this and decided to call JWT and they were awesome.

Project Low Buck Nissan SR20DE Part 2 > MotoIQ - Automotive Tech, Project Cars, Performance & Motorsports (http://www.motoiq.com/MagazineArticles/ID/897/Project-Low-Buck-Nissan-SR20DE-Part-2.aspx)

so these bearings are not really designed for the purpose of lubricating the crank better(although they do that) it is to force as much oil into that hole on the crank as possible to get maximum oil to the rod bearings. the calico coating was recomended by JWT not only for its friction and oil repellant properties, but the fact it tightens bearing clearances, which increases the oil pressure between the bearing and crank which forces more oil into that hole. but JWT only recommended this if you know your crank is straight. there is a guys that comes into JWT this afternoon that is the expert on this and im going to give them a call back to get the exact measurments...

in the article above it perked my interest into a full crank scraper/windage tray as well....

ill keep you guys updated for the select few who want to buil high HP, high reving, reliable SR's

[Croustibat]

Actually more pressure due to closer tolerances means less oil flow.

Closer tolerances let you have more safety when revving high, and thats it.

[Drift_FX]

Actually more pressure due to closer tolerances means less oil flow.

Closer tolerances let you have more safety when revving high, and thats it.

whats your reasoning on this?

less oil flow throught the main bearing, sure. but sr's dont have issues with main bearing oil supply/wear. it doesnt allow as much oil to squeeze throught the bearing and crank on the main so it forces more into the feed hole for the rod, which is where SR's desparately need more oil flow...

[Prok0]

As far as the calico coating is concerned I would do it, I just yanked apart my motor (Forged pistons/stock rod with ARP hardware, and calico coated ACL bearings) it had about 40k on it, and the bearings looked almost 100% brand new, the only visibly wear mark was on 1 rod there was slight wear through the coating, all other bearings I could see the very faint mark that the tool put on the top of the coating when we measured for clearances and that is it.

Granted my motor was assembled in a clean environment, all parts were washed multiple times prior to assembly, and all clearances were spot on, the coating definitely seemed to hold up well. I will be ordering more calico coated bearings for my new bottom end.

[Croustibat]

whats your reasoning on this?

less oil flow throught the main bearing, sure. but sr's dont have issues with main bearing oil supply/wear. it doesnt allow as much oil to squeeze throught the bearing and crank on the main so it forces more into the feed hole for the rod, which is where SR's desparately need more oil flow...

SR dont have oiling issues, except when camshaft sprayers get blocked. Or oil pump is worn.

There are so many people bashing these engines saying they are not reliable, and use ultra thick oil to get "the good oil pressures", when they really should replace their worn oil pump ... The way these pumps are made and regulated means the more pressure, the less flow; and if it cant give recommended pressure with recommended oil thickness, it means it does not produce enough flow. Therefore using thicker oil only leads to even more reducing the flow, ultimately killing the engine. Now if you are making more pressure at the bearings, oil flow will go the easiest way, i.e. the place with the least pressure. I dont know if it will go where you want it; i think it would go to the spray bars.

That is where the "CAs and SRs are crap because they eat their main and end bearings" come from. Not enough pressure while clearances and oil are ok ? Change your damn oil pump. Using fancy bearings wont make the pump work better. Not saying coatings are bad, but really if you get oiling problem, get to the root of it. Which, on these engines, is the pump and the spray bars for head problems. And blocked breathers.

[racepar1]

Actually more pressure due to closer tolerances means less oil flow.

Closer tolerances let you have more safety when revving high, and thats it.

Closer tolerances mean less pressure leakage and higher actual oil pressure downstream in the system. It may result in less flow due to the reduction in leakage, but that is simply a by-product not the determining factor. Higher oil pressure lubricates better and, as you stated, holds up to higher RPM better.

You're simply thinking about it all wrong. The flow is not the important factor it is the pressure in the system that is important.

[Croustibat]

Pressure is mandatory for hydrodynamics bearings (non roller turbos, mains and big end bearings, camshaft bearings), where flow is important for cooling.

Yes, flow reduction is a by product of increased pressure, that is exactly what i was trying to say. There is a point though were trying to increase pressure actually hinders flow so much there will be a huge pressure and flow loss after the place it happens (just like a roller bearing oil pressure limiter. This is wanted at a turbo, not at main and end bearings )

[Drift_FX]

SR dont have oiling issues, except when camshaft sprayers get blocked. Or oil pump is worn.

There are so many people bashing these engines saying they are not reliable, and use ultra thick oil to get "the good oil pressures", when they really should replace their worn oil pump ... The way these pumps are made and regulated means the more pressure, the less flow; and if it cant give recommended pressure with recommended oil thickness, it means it does not produce enough flow. Therefore using thicker oil only leads to even more reducing the flow, ultimately killing the engine. Now if you are making more pressure at the bearings, oil flow will go the easiest way, i.e. the place with the least pressure. I dont know if it will go where you want it; i think it would go to the spray bars.

That is where the "CAs and SRs are crap because they eat their main and end bearings" come from. Not enough pressure while clearances and oil are ok ? Change your damn oil pump. Using fancy bearings wont make the pump work better. Not saying coatings are bad, but really if you get oiling problem, get to the root of it. Which, on these engines, is the pump and the spray bars for head problems. And blocked breathers.


let me clarify, i didnt mean issues as in its a crappy system. i meant that the oiling to the rods is the weakest point in the system and can become an issue for highly modified/ hight hp motors.

and secondly i am refering to building a brand new motor, not polishing a turd. so the old worn out oil pump comment was irrelivent.

[wangan_cruiser]

so the old worn out oil pump comment was irrelivent.


i think he meant in general that people says ca and sr are unreliable due to the fact that they do eat their bearings for breakfast no matter what. but in reality these motor sat down in yards for days exposed thru climate changes. before making it in here shits makes the oil pumps seized.

[Croustibat]

i think he meant in general that people says ca and sr are unreliable due to the fact that they do eat their bearings for breakfast no matter what. but in reality these motor sat down in yards for days exposed thru climate changes. before making it in here shits makes the oil pumps seized.

Yes, that.

Well not only. Time takes its toll too, even if an engine has not been left lying around, at some point an oil pump change is needed. And at that point most people just see low oil pressure and ... put thicker oil to get the good pressures again. Which kills the engine "while oil pressures are good", as the price to pay for more pressure on a worn pump is "very poor flow".