Loose tolerance engine

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Holden 6 cylinder (1960s through early 80s) short stroke

Main Bearing diameter : 2.2"
Clearance : 1.6 to 2.4 thou (0.7 to 1.04 thou per inch)

Big end diameter : 1.9"
Clearance : 1.6 to 2.4 thou (0.84 to 1.25 thou per inch)

Oil Recommendation 20W-50

Holden 6 cylinder (1960s through early 80s) long stroke

Main Bearing diameter : 2.5"
Clearance : 1.6 to 2.4 thou (0.64 to 0.96 thou per inch)

Big end diameter : 1.9"
Clearance : 1.6 to 2.4 thou (0.84 to 1.25 thou per inch)

Oil Recommendation 20W-50

Holden V-8 (1960s through early 80s)

Main Bearing diameter : 2.4"
Clearance : 0.8 to 2.4 thou (0.33 to 1.0 thou per inch)

Big end diameter : 2.125"
Clearance : 0.07 to 2.2 thou (0.33 to 1.03 thou per inch)

Oil Recommendation 20W-50

Mini/Mini Moke

Main Bearing diameter : 1.75"
Clearance : 0.5 to 2 thou (0.29 to 1.14 thou per inch)

Big end diameter : 1.625"
Clearance : 1 to 2.5 thou (0.62 to 1.54 thou per inch)

Oil Recommendation 10W-30, 10W-40, 20W-50

Mini Cooper

Main Bearing diameter : 2.00"
Clearance : 0.5 to 2 thou (0.25 to 1.00 thou per inch)

Big end diameter : 1.625"
Clearance : 1 to 2.5 thou (0.62 to 1.54 thou per inch)

Oil Recommendation 10W-30, 10W-40, 20W-50

Ford Festive/Mazda 121 (thru to 1997)

Main Bearing diameter : 1.967"
Clearance : 0.7 to 2 thou (0.25 to 1.00 thou per inch)

Big end diameter : 1.57"
Clearance : 0.9 to 1.7 thou (0.57 to 1.08 thou per inch)

Oil Recommendation 10W-30

4Runner 20R (thru to 1997)

Main Bearing diameter : 2.362"
Clearance : 0.98 to 2.2 thou (0.41 to 0.93 thou per inch)

Big end diameter : 2.09"
Clearance : 0.98 to 2.2 thou (0.47 to 1.05 thou per inch)

Oil Recommendation 10W-40 through 20W-50 (above -7C)

4Runner 3VZE (thru to 1997)

Main Bearing diameter : 2.519"
Clearance : 0.94 to 1.65 thou (0.37 to 0.66 thou per inch)

Big end diameter : 2.165"
Clearance : 0.94 to 1.65 thou (0.43 to 0.76 thou per inch)

Oil Recommendation 10W-40 through 20W-50 (above -7C)


Doesn't seem to be a great deal of rhyme nor reason in the oil specs versus bearing clearances.
 
quote:
Originally posted by sbc350gearhead:

quote:
Originally posted by Patman:
Can I safely assume that my 95 LT1 350 engine uses these same clearances?
Click to expand...
Click to expand...
I can't say. The LT-1 is a gen 2 engine and is designed to spin to higher rpm and has more power than the vortecs.

LT-1 275-305 HP 325-335 ft lbs tq Redline
dunno.gif

vortec 250-255 HP 330-335 ft lbs tq 5000rpm [/QB]
Click to expand...
The redline is not all that high on my LT1, only 5800rpm (compared to 6250 for the LS1) I've always heard that the LT1 was very close to the original small block chevy, just that it got beefer parts, better heads/cam, the reverse flow cooling, optispark distributor (instead of a conventional one) and fuel injection.
 
I have no idea what constitutes a tight or loose engine, or where the cutoffs are one way or another. But I have been thinking a great deal about your heavier weight oil theory since our talk the other day. I am wondering if there is more to it than just clearances. My camry has a 2.2 liter 4-banger that holds 3.8 quarts of oil. That seems like a very small amount of oil, until I think about my truck and camaro which hold 5 quarts of oil for a 5.7 liter V-8. If my 350's had the same oil per liter of displacement as my camry, then they would hold 9.85 quarts. Maybe oil temperatures are different in larger engines. Maybe oil temps are higher in SBC's. Maybe the larger bore size (piston ring to bore area) has a different effect on the oil. Maybe the increased reciprocating weight puts more stress on the oil film at the bearings. I really have no idea, but I find your theory very interesting and I am going to try to gather more information on the subject. I am going to do some UOA's on my engines and see what I can come up with. After seeing your reports on RP 5w30, I wonder what my UOA's are going to look like.
rolleyes.gif


[ August 25, 2003, 10:32 PM: Message edited by: sbc350gearhead ]
 
quote:
My camry has a 2.2 liter 4-banger that holds 3.8 quarts of oil. That seems like a very small amount of oil, until I think about my truck and camaro which hold 5 quarts of oil for a 5.7 liter V-8.
Click to expand...
My puny 2.8 liter Audi motor holds already 5.3 quarts!

[ August 25, 2003, 10:37 PM: Message edited by: moribundman ]
 
quote:
Originally posted by moribundman:
Leo, I don't think that tight or loose clearances imply more or less quality or longevity per se.
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Well, I don't think they are a measurement of quality, but a measurement of "Precision" and maybe "efficiency"
Example: The M-16 rifle used in the military is built with very tight clearances. The result is a rifle that is very accurate, even over long distances and is much more predictable and repeatable. On the other hand, the Soviet AKs (Kalashnikov??) have much more looser clearances. The result is a rifle that you might be better off standing in front of it when they are shooting at you (I'm exaggerating a bit here), but it can go to places where an M-16 can only dream of. You can put that sucker in the water, sand, mud, grabble....pull the trigger and it will fire....all due to loose clearances.
Hope this help!
Rick
 
Heh you think thats small. My engine only holds 3.7L and its a 2L Turbo! I would like to think that there is enough oil left in the sump when im cornering hard at high RPMs..
 
quote:
quote:Originally posted by moribundman:
Leo, I don't think that tight or loose clearances imply more or less quality or longevity per se.

Well, I don't think they are a measurement of quality, but a measurement of "Precision" and maybe "efficiency"
Click to expand...
Yes, but will the tighter motor stay within specs and thus precise and efficient for as long as the looser motor?
wink.gif


How much wear and tear is there in a microfinished Nissan V6 engine after 200k miles compared to, for example, an Audi V6 engine? Have both engines worn the same amount? Are both still within specs, and which motor will stay longer within specs?

Reading up on current trends, I have noticed that there is increased talk about new "efficient" engines wearing out prematurely in Europe. People there warn now of buying used diesel engines with over 200k KM on the engine. 200k KM used to be NOTHING for a diesel! I also hear a lot of gas engines with Long Life Service that suffer engine damage. I also hear again of sludge in new motors. A lot of things may contribute:

- extended drains/Long Life service (up to 20,30, 40, 50k KM!)
- L(ong)L(ife) oils (low HTHS)
- engines built for low consumption, high efficiency

Personally, I'm pretty put off by what I hear about the latest engine designs.

[ August 26, 2003, 01:18 AM: Message edited by: moribundman ]
 
quote:
Originally posted by Last_Z:

quote:
Originally posted by Patman:
Here are the clearances for the LT1:

http://csce.uark.edu/~jgbertr/rb/engine_specs.jpg


Can you guys tell me if this is a rather loose engine, and if my theory on it liking a low 40wt best is correct or not?
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What about a 02 Z??
Thanks
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I believe the LS1 also likes an oil that is a high 30wt to low 40wt, as the best LS1 UOAs have been with oils in this range. Just wait until 3MP puts Amsoil in his Z28, I am confident his wear numbers will be lower since this oil is slightly thicker than M1.
 
quote:
I don't understand these numbers. Mine are like that too. That is a huge range!! Are they saying that brand new it has to be the smallest value and as it wears it is still acceptable until the largest value?
Click to expand...
No, those figures represent clearances that are within specs.

I'll give you an example:

Main Bearing Oil Clearance: 0.018 to 0.045 mm
Service Limit: 0.10 mm

That means, if the main oil bearing clearance is anywhere between 0.018 and 0.045 mm, then the this bearing is within normal specs. If the clearance reaches 0.10 mm, then the bearing has reached the end of its life.

I guess, in this example the main oil bearing clearance could also be expressed as 0.0315 mm +/- 0.0135 mm for a sound bearing that is within "new" specs. 0.0315 mm would be the mean value for the bearing clearance, +/- 0.0135 would be the allowed manufacturing tolereance.

Please, anybody correct me if I'm wrong.

[ August 26, 2003, 02:23 PM: Message edited by: moribundman ]
 
Hmm, that doesn't make sense...why don't they express it that way then?

And seems like that could create some problems, especially for that 5.7 SBC. It looks like they want the #1 to be smallest, next 3 a little more open, and the #5 to be most open. But if that entire range is an acceptable value, you could have a .002 #1, a .0015 for #2,3,4, and .001 for #5...entirely the opposite of what they want.
 
How does clearance volume play into the equation??? A SBC 350 and SBC 400 can both be running 0.003" main bearing clearance, but the clearance volume on a 400 sbc will be larger due to the larger main journal size. (Volume is a function of clearance, bearing width, diameter)

Does anyone know if this has any effect on required viscosity?
 
quote:
Originally posted by moribundman:

quote:
My camry has a 2.2 liter 4-banger that holds 3.8 quarts of oil. That seems like a very small amount of oil, until I think about my truck and camaro which hold 5 quarts of oil for a 5.7 liter V-8.
Click to expand...
My puny 2.8 liter Audi motor holds already 5.3 quarts!
Click to expand...
I've got ya beat, my 2.5L Duratec holds 5.8quarts (in the SVT form) but I safely fill it with 6quarts, especially for Autocrossing.

It may hold just a tad bit more, with the oil lines for the TURBO!!!
wink.gif


TB
 
quote:
I don't know if others are posting clearances or tolerances. I posted the clearances of my engine, and I skipped the tolerances.
Click to expand...
these are all clearances, tolerances would read with a target size and variance +/- number i.e. .0015" +/-.0007"
 
I don't understand these numbers. Mine are like that too. That is a huge range!! Are they saying that brand new it has to be the smallest value and as it wears it is still acceptable until the largest value?
 
Is this stuff getting over your heads guys?
I'll start with you 350sbcgearhead.
You are building this 350 SBC for racing.
The class you are racing in specifies a flat tappet camshaft.
The cam is dependent on its lubricant from______?
The specs on the factory crank allows you to choose a clearance for the rods and mains.
Do you pick the tightest clearances yes or no?
(nothing to do with oil viscosity or journal size)
The engine Gru from the trick of the month club tells you to use full groove main bearings.
Do you take his advice since they will allow more oil to get to the bearings?
You are going to run very high compression with suspect quality and octane fuel.
There lies a high risk of ignition detonation.
Would that require you to run tighter rod bearing clearances?
You are going to use a factory block and crank.
The crank may flex under high load.
Does crank flexing affect main bearing clearances?
What is more important?
A high pressure oil pump or a high volume pump?
Engine oil flows in and out of crank and rod bearings.
Would adding a groove in the bearings help the load capacity by increasing the volume of oil flowing into and out of the journal and clearance area?
I'll stop here and let you guys chew on this for a while.
fruit.gif
 
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