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by ptuomov
Thu Dec 05, 2019 9:07 pm
Forum: Engine Tech
Topic: Rod strength
Replies: 35
Views: 1036

Re: Rod strength

I'm not an engineer, but I have read somewhere that they use a weight that they drop from some height to break the rods. Perhaps the 1500 lbs refers to the weight but the height is unspecified.
by ptuomov
Thu Dec 05, 2019 8:27 am
Forum: Engine Tech
Topic: 1JZ/2JZ “Supra” rod bearing options
Replies: 17
Views: 434

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

Here's another novice question about rod bearings. Suppose that you run Clevite H or HX type bearings. The big end bore specification is min/mean/max 55.024/55.033/55.042mm (2.1663/2.1667/2.1670"). Would you rather run a bearing in a big end housing that is 0.010mm (0.0004") too loose relative to th...
by ptuomov
Wed Dec 04, 2019 7:49 am
Forum: Engine Tech
Topic: when are 3/4 grooved main bearings needed for bbc ?
Replies: 227
Views: 5076

Re: when are 3/4 grooved main bearings needed for bbc ?

Does anyone have a Coriolis Meter aka fluid mass flow meter on a running car? That would be a bad a$$ way to debug a wet dump engine!
by ptuomov
Wed Dec 04, 2019 7:26 am
Forum: Engine Tech
Topic: 1JZ/2JZ “Supra” rod bearing options
Replies: 17
Views: 434

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

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 ...
by ptuomov
Wed Dec 04, 2019 5:13 am
Forum: Engine Tech
Topic: 1JZ/2JZ “Supra” rod bearing options
Replies: 17
Views: 434

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

What's the maximum rod journal oil hole size as a fraction of rode bearing length that you guys would recommend?
by ptuomov
Tue Dec 03, 2019 5:50 pm
Forum: Engine Tech
Topic: 1JZ/2JZ “Supra” rod bearing options
Replies: 17
Views: 434

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

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?
by ptuomov
Tue Dec 03, 2019 3:28 pm
Forum: Engine Tech
Topic: Plenum box with two inlets and one outlet
Replies: 8
Views: 1643

Re: Plenum box with two inlets and one outlet

I was going to say that a blow through maf sounds like a lot of trouble. But so does blending two maf signals, I don't know of many ECU's thay could handle that and I'd doubt the accuracy of using only one maf in a twin system. The Z32 was twin everything except airflow meter The box worked great. ...
by ptuomov
Tue Dec 03, 2019 1:19 pm
Forum: Engine Tech
Topic: Valve spring setting for turbo boosted engines ?
Replies: 28
Views: 1537

Re: Valve spring setting for turbo boosted engines ?

When we boost NA engines and see a need for more valve spring, I am not convinced it is the boost. I am still under the impression, there was always an issue in the valve train just a boosted application makes it much more noticeable. Again, give factual data showing the need for the higher spring ...
by ptuomov
Tue Dec 03, 2019 12:32 pm
Forum: Engine Tech
Topic: 1JZ/2JZ “Supra” rod bearing options
Replies: 17
Views: 434

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

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
by ptuomov
Tue Dec 03, 2019 12:30 pm
Forum: Engine Tech
Topic: Rod strength
Replies: 35
Views: 1036

Re: Rod strength

We’re working on these super light, non fragile new custom con rods. Bearings that fit these may be a little short:
A8A345B0-10CC-4443-B77A-9F6220C5B2DA.jpeg
The pistons should not score alusil, nikasil, or cast iron! Pin weighs more than piston and rod combined...

;)
by ptuomov
Tue Dec 03, 2019 11:04 am
Forum: Engine Tech
Topic: Plenum box with two inlets and one outlet
Replies: 8
Views: 1643

Re: Plenum box with two inlets and one outlet

Whatever happened with this? Did you guys end up using the box? How did it work? Anything done after that as far as modifying the box or making an entirely new one based on results gathered from this one? The box worked, but we relocated the MAF (and went to dual MAFs) so now there's a y-pipe there.
by ptuomov
Tue Dec 03, 2019 8:47 am
Forum: Engine Tech
Topic: Rod strength
Replies: 35
Views: 1036

Re: Rod strength

I fully understand the procedure used to split it even before I posted this, I was just very surprised that cracking at the same time 2 of the most meaty sections of the rod took only 1500 lbs of applied force! Here's a question: Do they press it with 1500 lbf force or do they have a rig that drops...
by ptuomov
Mon Dec 02, 2019 8:55 pm
Forum: Engine Tech
Topic: Wrist pin diameter and rpms
Replies: 21
Views: 673

Re: Wrist pin diameter and rpms

I think these brand new M139 wrist pins are tapered from the factory, at least as far as my eye can see:
221A52AA-5A79-472E-B262-BFCAFEC9C6A0.jpeg
by ptuomov
Mon Dec 02, 2019 8:20 pm
Forum: Engine Tech
Topic: Rod strength
Replies: 35
Views: 1036

Re: Rod strength

Is the problem (or the perceived problem) of fragility about powder metal vs. conventional forging? Or is it about designing the material to make the end cap crackable? There are conventionally forged cracked rods, but they also have to be heat treated etc. to be crackable. I have ancient non-cracke...
by ptuomov
Mon Dec 02, 2019 6:22 pm
Forum: Engine Tech
Topic: How to fight exhaust reversion when the primaries are way too short
Replies: 142
Views: 9875

Re: How to fight exhaust reversion when the primaries are way too short

The ls7 style collector resembles both an anti reversion cone and a pulse terminator box. Isn't it effectively running "zoomies" with back pressure at this point? It looks like it works because the CSA change is so massive the pulses can't really interfere with other cylinders. Or did I get that wr...