Chevy Rods

[Lextreme II]

Hey Gang,

I have been working very close with my engine builder and research on my own. The 1uzfe stocks are very strong already with 6 bolt main, its almost bullet proof. However, our stock pistons are really bad. Most of the problems with the first generation pistons are the ring lands. I have personally seen few engines with the same ring lands crack pattern.

Anyway, make long story short. I have been reading and matching off the shelf products from the domestic arena. Here is what i found.

Chevy Rods:
Large journal 2.100"
Piston Pin = .927"
Rod length 5.7"

UZFE (All uzfe engines):
Crank End (big end) Diameter 2.165"
Pin End (small end) Diameter .864"
Rod length 5.7455"

As you can see the numbers are pretty close. The Chevy larger journal is about .065" smaller and the pin size is .063 larger and the rod length is about .0455" shorter. The rod length and pin size is not an issue. Custom pistons will take care of that.

The Chevy rods are dirt cheap. Forged H-bean rods capable of handling 1000 hp is about 350 usd. Here is the solution:
1. Machine .065" off the 1uzfe crank
2. Get a set of custom pistons to make the whole thing work. The custom pistons also use chevy pins. Machining .065" off the crank is no big deal. Chevy have smaller crank than uzfe and they are making huge power. Machining that little amount would not be a problem at all. Since the crank is machined to Chevy rods size, then we can use chevy rods bearings too and they are also dirt cheap.


What do u think? Here are some pictures of 1uzfe and 3uzfe rods:


Here are few pictures of H-bean Chevy rod. The first rod is from Eagle and the second rod is from Scat.

Boy, with the above combo..... you save money on parts and you will have a bullet proof shortblock.

 

[toyotav8boat]

rods &pistons

sounds great
another group buy on pistons????

pete

 

[Zuffen]

As the Chev rod is shorter than the 1UZ why not fit a new little end bearing to the chev rod that effectively shortens the Chev rod to 1UZ specs and use 1UZ or the Ross group purchase pistons?

 

[elhsupra]

Since you have to grind the crank down, why don't you offset grind it? That way it will make the difference up from the rods and you can use the pistons from the group buy.

 

[Lextreme II]

There are many ways to make it work. The method Eric and Rod mentioned are also good for the Ross or stock pistons. Here are some math i am playing around with:

larger journal is about .065" smaller
and the pin size is .063 larger and
the rod length is about .0455" shorter

If you put in a bearing for the pin side with .063, then we grain half of the rod length of .063 which will increase the rod length from 5.7 to 5.7315. Therefore the Chevy rods only .0315" shorter and with standard crank reduction, we are only .0315" and should not be a huge problem at all. It just lower the compression slightly.

However, with the grind Eric mention will take care of the .0315" difference. However, if you guys are interested in a group buy. I can work with Ross and modify the pin size and location slightly to make it work perfectly for the first generation 1uzfe.

 

[Zuffen]

Lex,

Just so I have this right you're looking at having Ross make new pins for the pistons that will fit the Chev rod. We would then need to machine the pistons to accept the pins.

Am I right in my understanding?

It makes sense to me.

 

[JDMfantasy]

This is all pretty interesting...
I'm looking to lower my compression as well, so having a slightly shorter rod length may be beneficial. Does anyone know what the new compression ratio would be off hand? Say you grind the crank down the .065 required for the Chev rods, and dont mind having the shorter rod length, the Ross pistons (pin hole) would then need to be machined from the .8xx up to the Chev .9xx diameter, correct?? I've got myself all confused.......

 

[Lextreme II]

Rod,

You can use your current Ross pistons with a pin bearing to make up the size difference. However, machining the Ross pistons might work too.

 

[autronic]

Guys:

In order to use Chevy small block rods in an 1UZFE engine you have to use
the older Chevy SB 327 rods with a 2" big end. The later Chevy SB 350 have
a 2.1" big end.


The 1UZFE rod measures 52.0 mm with the bearing in place, take the bearing
out and the big end measures 55.0 mm.

The Chevy SB 327 rods have a 2" bore ( 50.8 ) when measured with the bearing
in place, take the bearing out and the big end is roughly 54 mm. This is
about 1 mm smaller than the 1UZFE and the rod can be macined out to take the
bigger 1UZFE bearing.

The Chevy SB 350 measures 2.1" ( 53.34 mm ) with the bearing in place and
about 56.6 mm without bearing, this is to big and this rod can not be used.


The pictures shows 3 different connecting rods:

Left: Chevy SB 327 with 2" big end, longer 6.0" centre to centre distance
Centre: Lexus 1UZFE
Right: Chevy SB 350 with 2.1" big end, stock 5.7" centre to centre distance


You have to machine the Chevy rods go get them to fit anyway. The Chevy SB
rods are wider at the big end, .940" ( 23.87 mm ) vs. 22.9 mm for the 1UZFE,
so about 1 mm have to come off and this can be done in a lathe and while it's
in the lath why not modify the big end diameter to accept a Lexus 1UZFE big
end bearing ?


This way it is possible to use the Chevy SB 327 rods without regrinding the
1UZFE crankshaft.

 

[autronic]

The pistons can then be ordered about 1.1 mm taller and with Chevy SB pin
( .927" - 23.54 mm ) instead of the 1UZFE pin ( 22.0 mm )

 

[autronic]

Zuffen:

There is enough "meat" in the pin bearing to move the piston 1.1 mm
up, but it's not something I'd do to my rods, I have heard of people
doing it with mixed results.

 

[Zuffen]

Autronic,

Can you give me some more information on the mixed results.

I figure if we are machining the bore of the big end why not machine it off centre so you gain about .5mm in the bottom end and this only leaves .6 to find in the top end.

I haven't spoken with any specialists but it sound interesting.

Has anyone thought to ask the manufacturer of the rods if they could build a modified Chev rod to fit our engine? Whilst I don't expect it to be cheap it has to be better than the prices we are seeing quoted for custom rods.

 

[Lextreme II]

There couple of options to make it work. The older rods i also looked. Matter of fact the older rods are dirt cheap too. NASCAR use those rods and they are resold on ebay for less than 80 a set. "Type Carrillo Rods on ebay" The 5.7 is very similar to the 1UZ and the crank diameter is very similar. Regardless it will not be a perfect fit. The 1UZ has 2.165" and Chevy has 2.100".

If you use the older rods, then we would need to machine the 1uz crank a lot more.

The pictures shows 3 different connecting rods:

Left: Chevy SB 327 with 2" big end, longer 6.0" centre to centre distance
Centre: Lexus 1UZFE with 2.165 big end with 5.7455"
Right: Chevy SB 350 with 2.1" big end, stock 5.7" centre to centre distance

I talked to Ross yesterday about few changes and they say it not a problem using the 5.7 and move the pin position down slightly.

Here is what the engine builder need to do:
1. Machine .065" off the stock 1UZFE crank
2. Machine .060" off the Chevy rod (Crank side)

The stock thickness of 1UZ rods (crank side) are .880" and the Chevy rods are.940"

Machine the above and custom make the pistons would be perfect along with ARP all round...

 

[Zuffen]

Lex,

The mods you describe were good up until the custom pistons!

What if we want to keep stock pistons or even the group purchase pistons?

Will the mods work with the Ross pistons from the GP without modifying the pistons?

 

[Lextreme II]

i need to call Ross about the pin adapters for the pistons....

 

[SCV8]

It looks like you'd need to grind the crank regardless to, and that offset alone would get you to within .013-.014 of the original deck height.That would allow you to use stock-sized pistons.
I would imagine that it would counter-productive to take material from the rods.

 

[1UZ-HZ]

I'm not adding anything technical here but I really beleive, and I'm sure I'm not alone here, that the rods will have to fit the Ross pistons a few of us have already bought. Otherwise they are totally useless for most of us going for big HP(which is what they are desinged for).

 

[TOBES]

Lets try this again with the correct journal size (I found the engine specs??)............

The 1UZ rod is 145.93mm long (5.745" x 25.4mm)
The SB Chev rod is 144.78mm long (5.7" x 25.4mm)

We need to find 1.15mm to place the piston at the same deck height....

The lexus crank journal is 51.98mm (2.0465" x 25.4mm)
The Chev small journal rod is 50.80mm (2.0" x 25.4mm)

We need to grind the 1UZ crank Journal by 1.18mm to suit the Chev rod.
By offset grinding the crank 1.18mm the piston is still short of the correct deck height by 0.56mm.

Not too much of a drama for FI where we can accept the lower compression...

Perhaps we can install an 0.56mm offset bush in the pin end to accomodate the 1UZ pin dia.......
Or use an undersize chev bearing to increase the offset.....

On the positive side we have just stroked the motor by 1.18mm to around 4.15l....

We are told the stock crank is good for 1000hp plus so reducing the dia of the crank pins by 1.18mm should still allow sufficient strength. As Lex says the Chev small blocks make good hp and survive.

 

[TOBES]

Sorry, had to edit the last post as I worked off Lex's apples vs oranges dimensions.

Autronic is correct in that the large journal chev rod will not work as the bearing ID is 2.1" and the lexus rod journal is smaller at 2.0465". The only option is the 5.7" small journal rod at 2.0" bearing ID.
From the figures in the last post the approx 0.6mm lower deck height should not affect the Ross piston users too much.

What is the effect on the squish area's in the head?
How much meat is there in the deck and can they be cut to reduce the difference? Do the liners sit proud of the deck and do they need to be removed before the deck is cut? Probably need to port match the inlet manifold afterwards....

 

[Zuffen]

Decking the block 0.60mm is ugly. You also end up with manifold and water bridge problems.

It would make the engine lower in height so may suit some.

My choice would be to have new little end bushes made for the rods.

Machine the little end oversize but in the correct position then have a new little end bush made to fit the 1UZ or Ross gudgeon (or piston) pin.

This would stop any problem with an offset bush rotating and maintain the correct squish figures.

I think we need the superior intelect of JBrady about now.