BiTurbo228

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

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.

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.

Just caught this one, love a good Scimitar. Especially the SE5s.

I bought an alloy rad from the States that was a really nice design (good thick cores), but sprung a leak where the fins joined the end tanks. Then bought a cheapy eBay special alloy rad (not actually all that cheap) which has thinner cores, but seems to have held up. Probably just unlucky...

Don't I know it! £300 a pop...

I feel like I've got some shims somewhere, but I'd need to find them...and then post them from the UK anyway. TBH it's the finding that will probably take the time...

Maybe what you need is two basic bike mufflers The stock SD1 exhaust has a swan pipe tip and if you stick a straight one on that pulls fumes into the cabin. Maybe a side exit might help, even if it's not a full swan neck. I've got proper side pipes on my SD1 and it's fine while driving along. Does steadily gas you when you're stationary though...

Well, that sounds like a saga and a half! Always the way when you're working to a tight deadline, though I must admit I haven't had the whole 'bitten by a cat I was trying to help' thing happen to me specifically... Sounds good though. Sounds real good.

Probably smarter. I just took one look at the price of remanufactured master cylinders or my Mk1 and thought 'screw that for a game of soldiers'. Been thinking of trying to do a servo-into-twin-masters things somehow as that'd open up opportunities to do something similar with my SD1, but not got that sussed yet.

Not sure what your engineering stuff would say about it, but I've made a twin master setup to work with mine. Cut out the middleman of a pendulum box and just made a plate that bolts to the bulkhead: A T2000 might be on the upper limit of what I'd want to drive on the street with manual brakes, but hopefully it'll be fine!

No mine was fine interestingly enough, though I did end up doubling up on the copper washers as my helicoiling wasn't as straight as I'd have liked it (did it on the car which was a fun experience...). I think I did give it a bit of a light blocking down to take off any high spots and raise any gouges that might make sealing trickier.

Yeah I've got a straight plug with a copper washer in mine. The tapered one mashed the threads before it sealed and I had to helicoil it.

Yeah maddening. Checked for shaft vibration on all your auxiliaries?

Glad the bottom end's fine. I read on Guy Croft's site a while ago that sometimes the turbo blocks can develop a warp that robs power, possibly due to a manufacturing defect as it seems to be random. Not sure if it affects other blocks, but if the crank spins freely it's probably not that. What are the rings like on the pistons? Any of those caked up? I remember when I rebuilt my Triumph engine the first time I forgot to clean out the ring gaps and it was very stiff to turn in patches.