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Posted

All part of the R&D process, this shit happens even on the well trodden path of engine building. Need a couple spare engines in the shed right?

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Posted

I was going to say its time to find the Hybrid version for more compression and then realized the 4GR doesn't a hybrid version

5GR crank for less stroke?

https://www.youngstarmotor.com/sale-42301339-steel-material-automobile-engine-crankshaft-for-toyota-5gr.html

And some 5GR rods I am guessing to suit the lower stroke :p

While I was having a look around, they are in development for the 2GR

https://denstoj.com.au/products/2gr-toyota-engine-rocker-retainer-kit-by-denstoj?srsltid=AfmBOorA3rvKUNaD8zbd5PGwaiuHbx6VQzbMclxuEL08FcnIcIKc-o-J

They already do an FA20/FB kit

https://denstoj.com.au/products/fa20-fb-rocker-retainer-kit?srsltid=AfmBOoqp3gIOVdFmXS5jl8vM456uqwKgQtf4XRqkrwI0kNtDUUw1qWOz

And one for the GR corolla/Yaris etc

https://denstoj.com.au/products/g16e-gts-yaris-gr-rocker-retainer-kit-by-denstoj?pr_prod_strat=e5_desc&pr_rec_id=a7fc8dd21&pr_rec_pid=7004431941798&pr_ref_pid=7603717374118&pr_seq=uniform

Even for the 4G63 :p

Edit: Looking closer I don't think that kit solves the problem if the pin is falling out more googling required

Posted
4 hours ago, shrike said:

5GR crank for less stroke?

https://www.youngstarmotor.com/sale-42301339-steel-material-automobile-engine-crankshaft-for-toyota-5gr.html

And some 5GR rods I am guessing to suit the lower stroke 😛

 

The longer term plan if the 4GR goes well, and there arent any insurmountable issues. 
Is to get a 3GR and then put a 2MZFE crank in it. 
This gives exact same bore and stroke as a 5GR, but uses parts that are a bit easier to source here.
A friend has a 2MZ for me in storage, and there's a few 3GRs at pickapart at the moment.
However it looks like the greater difficulty, well before the current stroke length is a limiting factor. 
Is getting the valvetrain to play along.

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Posted

3GR heads would offer benefits in much bigger valves. Probably not worth getting one for these teething stages, but as an evolution it would be neat.

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Posted

I'm sure you've thought of this Dave, but if the cam is the same, will the 2gr rockers also solve your head falling apart issues? pun intended. 

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Posted

The rockers and hydraulic lifters, vvt pulleys and lots of other bits are all exactly the same between all of them.

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Posted

I think from memory, Windom, Camry and the weird import Avalon. If I remember the larger capacity is in the Highlanders of same period and maybe Prado?

I always thought the 2mzfe was a pretty cool motor 15 years ago, but newer stuff surpasses it now

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Posted


Wiki says: 
image.png.cedfaf2e6d618d71914e2be4a86dcb68.png

So not hugely common. But still cheaper and easier than sourcing a 5GR crank from China.
I'm glad I've got one set aside for me already, so I can see if it will actually work.

Posted

It'd be interesting to know what length the 2MZFE rods are. I've got the 5GR rods at 154.38mm which is the odd one out of the GR family. Not sure what that does to your piston compatibility.

There's a few estimates and fudges in my calcs, and they're for a 2GR with various different crank lengths, but dropping to a 69.2mm crank from a 77mm crank shaves about 350kg off the peak weight exerted upon the crankpin at 10,000rpm (assuming forged pistons and rods). That's down from 3397kg peak to 3056kg.

For reference your 1NZ was at about 1702kg at 9000rpm with forged internals, but it did have a weedy little crank. 2JZs start to show increased wear rates above about 2700-2800kg, but will run to 3000-3250kg if you don't mind about that. BMW S54s are at about 3350kg at 8000rpm, though they have semi-complex issues around bearing failures that no-one's found a definitive cause for (some fail at 8000rpm, but there's enduro cars running 8200rpm and ~3500kg with no issues). RB26s start experiencing issues between 7600rpm/2100kg and 8750rpm/2800kg, but it's oil pumps that they grenade so that's probably torsional vibrations. KPR's short-rod 4AGE at 10,000rpm is a smidge under 3000kg.

Who knows whether these limits are anything to do with peak crankpin loads or not, but it's good to see that at least 10,000rpm on a short-stroke GR doesn't seem wildly out of the realms of these other high rpm engines.

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Posted
15 hours ago, Roman said:

The rockers and hydraulic lifters, vvt pulleys and lots of other bits are all exactly the same between all of them.

Oh wow. I'd assumed 4gr would be lower spec than a 2gr.. Now I'm a little worried my lifters to rattle themselves to pieces with RPMs. Redline is at 6500 or something silly low though. 

 

 

 

@BiTurbo228 super interesting comparison. Only advantage in a GR motor is the V6 crank is probably more compact (and hence less distance between supports) than a straight 6 in JZ, RB or S54. Who knows what the limiting factor will be!

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Posted

Yeah these have super grunty 6 bolt main bearing caps.
2 more bolts come in through the sides of the block.
But there are two rods between each bearing cap. So win some lose some, I guess.

I figure this is one of the cases where the modular nature of these motors works in my favour. As it's all setup to be strong enough for the 3.5 (or arguably 4 litre) versions of this engine. 
So I'll have some more spinny forces going on, but nothing near the loads people are throwing at boosted 2GRs making 700hp or whatever.

image.thumb.png.4783102e0943582ddba0d367eb498011.png 

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Posted
10 minutes ago, Rhyscar said:

Oh wow. I'd assumed 4gr would be lower spec than a 2gr.. Now I'm a little worried my lifters to rattle themselves to pieces with RPMs. Redline is at 6500 or something silly low though. 

It seems more likely that a VVT pulley would be the first thing to go. 
There have been some failures even with standard 2GR motors.
But you get lots of notice as it will rattle on cold starts if the pin isnt engaging.

Or otherwise having a rocker fall out. 
Someone said that Toyota revised the valve springs to a beehive type to address the issue that the earlier motors had with firing the rockers out occasionally.
However I'm not sure at what point that changed.

Although, a lot of these things are a non issue if you're keeping to factory rpm limit, for the better part.

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Posted
11 hours ago, Rhyscar said:

@BiTurbo228 super interesting comparison. Only advantage in a GR motor is the V6 crank is probably more compact (and hence less distance between supports) than a straight 6 in JZ, RB or S54. Who knows what the limiting factor will be!

Yeah a lot of the issues with the I6s will be something to do with torsional vibrations, which the V6s will be much more resistant to. Even though the crankpins are shared, they're so much more compact than the long noodly cranks of I6s. Judging by Roman's picture the GR crank has proper flying arms between adjacent crankpins rather than the sketchy offset-ground pins of things like old Buicks, so that should help a lot with stiffness too.

I was half thinking about torsional issues and half thinking about pressure on the oil film between big end bearings. All exciting stuff we get to find out about :grin:

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