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1JZ/2JZ “Supra” rod bearing options

General engine tech -- Drag Racing to Circle Track

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ptuomov
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1JZ/2JZ “Supra” rod bearing options

Post by ptuomov » Sun Dec 01, 2019 12:47 pm

What are the best 2JZ rod bearing options for high rpm boosted engine? CB-1628HX, CB-1628H, or Toyota factory bearings? Or something else?

This is for a different engine with a similar 52mm crankshaft journal, a little shorter stroke, about same component weights, turbos, and a comparable 8000 rpm practical redline as a mildly hot rodded Supra.

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by ptuomov » Sun Dec 01, 2019 1:48 pm

For what it’s worth, here are the clearances they run in Supras from the factory:

http://www.2jz.se/application/files/531 ... rances.pdf

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by jed » Sun Dec 01, 2019 2:51 pm

Which bearing you use is determined by what oil clearance you want and what weight oil will be used and is
The oil synethic or mineral.
5 main factors in oil clearance are
1. Shaft size
2. Housing bore
3. Bearing wall thickness
4. Bearing crush
5. Torque applied to bolts
Once you determine the clearance wanted install the bearing in the rod and torque to spec.
Measure vertical housing bore then subtract shaft size. Mix and match bearings to achieve the clearance wanted.

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by ptuomov » Sun Dec 01, 2019 3:03 pm

jed wrote:
Sun Dec 01, 2019 2:51 pm
Which bearing you use is determined by what oil clearance you want and what weight oil will be used and is
The oil synethic or mineral.
5 main factors in oil clearance are
1. Shaft size
2. Housing bore
3. Bearing wall thickness
4. Bearing crush
5. Torque applied to bolts
Once you determine the clearance wanted install the bearing in the rod and torque to spec.
Measure vertical housing bore then subtract shaft size. Mix and match bearings to achieve the clearance wanted.
Yes, but which 2JZ bearings? I assume there’s more eccentricity, for example, in “race” bearings and bearings people use with strokers... ...but assume makes an a$$ out of u and me. I’d also assume that race bearings are harder for detonation. I think we can at least match or improve on the Supra rod big end deformation at high rpms.

The basic clearances with Supra bearing specifications are close to where I want them:
5F93F007-3308-4A42-A1F5-993AD8A278BA.png
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Re: 1JZ/2JZ “Supra” rod bearing options

Post by ptuomov » Sun Dec 01, 2019 3:23 pm

The “hot rod magazine” recommendation of 0.001"/in or 0.1% of journal diameter is pretty loose for the rigidity of the Porsche or Supra crankshaft. Tighter clearances hold load better because of the geometry, one just needs stiff parts and good manufacturing tolerances. Then there’s the oil viscosity, flow, and cooling — we are running 10w-60 or 20w-50 types of synthetic oils.

2JZ was designed in the 1990's (or maybe 1980's if you count 1JZ) so it has tighter target bearing clearances than 928 that was designed in the 1970s. The minimum clearances are about the same. There's no mystery to that in my opinion, the big thing with both engines is not to go below the minimum. The minimums for both engines are about 0.04% of the journal diameter.

In my opinion, for custom rod prices, we have to get them at least as good manufacturing tolerances as Toyota factory got in the 1990's.

In bearing clearances, in my opinion, one needs to really pay attention to the minimums. The minimum specified for 928 is 0.020mm. (The minimum implied by journal and big end bore tolerances for 928 is 0.016mm, which would be out of spec.). So the 928 can run them reasonably tight within the range.

2JZ has tighter range midpoint, but the tolerances are tighter and therefore the minimum specified is actually a bit larger than 928 at 0.023mm. This additional 0.003 may reflect higher rpms that Toyota run factory stock. (2JZ implied minimum is 0.013mm, which is significantly smaller than the minimum clearance.)

So 928 minimum allowed clearance is 0.020 and 2JZ minimum allowed clearance is 0.023. In practice, the 2JZ bearings have much more eccentricity, so where the bearings bind they are looser than that where it counts.

The 2JZ rod and bearing on 928 journal is expected to give target 0.041mm clearance, which is about right in my opinion and not too far from Conventional wisdom. The 2JZ X rod bearing would give target 0.057mm which is too large for my taste, but it would probably run ok still. But I don’t really know.

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by ptuomov » Tue Dec 03, 2019 12:32 pm

So any comments on King vs Clevite vs stock Toyota vs any other rod bearing makes for Supra?

Here’s where they’ll be going:
FDE6E441-E129-4198-8AA9-04F464575543.jpeg
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Re: 1JZ/2JZ “Supra” rod bearing options

Post by bentvalves » Tue Dec 03, 2019 5:44 pm

KING xp series bearings p-max black and call it good I reckon.

I wonder who manufactures the bearings for Toyota however, just cause.

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by ptuomov » Tue Dec 03, 2019 5:50 pm

bentvalves wrote:
Tue Dec 03, 2019 5:44 pm
KING xp series bearings p-max black and call it good I reckon.

I wonder who manufactures the bearings for Toyota however, just cause.
Why the cheaper Kings rather than the more expensive Clevites? Other than price? Or did I check the prices wrong?

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by bentvalves » Tue Dec 03, 2019 9:21 pm

King has been my bearing of choice for sometime now after reading all the positive reviews online. Supposed to be some of the better bearings available according to many builders.

they have some sort of new coating process out as well, its not p-max black but something or other along the lines of a nano composite. saw the ad in engine professional recently.

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by ptuomov » Wed Dec 04, 2019 5:13 am

What's the maximum rod journal oil hole size as a fraction of rode bearing length that you guys would recommend?

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by KnightEngines » Wed Dec 04, 2019 6:54 am

I use ACL race, have them in 1300hp 2j's at .0025" clearance.

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by ptuomov » Wed Dec 04, 2019 7:26 am

KnightEngines wrote:
Wed Dec 04, 2019 6:54 am
I use ACL race, have them in 1300hp 2j's at .0025" clearance.
Cool thanks. ACL fully back in business after the financial difficulties?

Also, it’s interesting that you’re using almost exactly double the stock 2JZ stock rod bearing clearance specification. Do you think the stock bearing spec is too tight for higher rpms (what’s the redline for your engines), or just that little loose never hurts anyone too much?

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by KnightEngines » Wed Dec 04, 2019 7:56 am

I was looking after a drag 2j for quite a few seasons, reading the bearings at freshen time led to .0025" being about right.
That one had crower rods, a bit over 1300hp at around 8200rpm if I recall correctly.
Cheaper rods may want a little more, those crowers were tough, it once had a boost line fitting swapped around & went over 50psi, lifted the head, pushed out the mls gasket, crossfired & split the plenum.
It bent the gudgeon pins in the JE pistons a solid .020", the rods shrugged it off.

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by steve316 » Wed Dec 04, 2019 9:08 am

that is what I would call a good recommendation for crower & acl .

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Re: 1JZ/2JZ “Supra” rod bearing options

Post by jed » Wed Dec 04, 2019 9:35 am

Tony do you know what kind of oil an weight??

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