working on long rod option for 3.7 and had some trash HR heads for mock up and here is how it works:
3.5HR block casting EYO
3.7VHR blcok casting EYO (same block as HR)
2 pick is 3.7 crank + HR conn rod + HR piston, way too tall
3 pick is 3.7 crank + HR conn rod + DE piston, still too tall
custom pistons will be needed! success!!!

 

Interesting. Crank is a direct swap?

Custom set of pistons would be a cheap way to get a stroker setup for the HR.

 

this is in a 3.7 block... soon it will be transfered to 3.5 block just to double confirm results... should be the same

 

I don't really understand your first post? It is a 3.7 vhr block that you are making a 3.7 L? or it is a 3.5 HR that you are making a 3.7?

 

He's combining parts from the 3.7 and 3.5 to come up with a "Long Rod" engine. In theory, this has several advantages. One of which is being able to rev higher or maintain high revs for longer periods of time without damaging the engine. It should also decrease the risk of spun bearings, and it keeps the piston in dwell for a longer period at TDC. There's some down sides as well, and I'm no expert, but this seems interesting.

Regardless, it's nice to see someone doing something new.

 

Looks interesting. Cant wait for updates

 

yes it is a 370z shortblock with 350z heads... the 3.7VHR rotating assembly will work but the 3.7VHR(EY) rods are little dumpy things and the pistons don't have exhaust valve reliefs... 3.5HR(JK) rods are the same size on the big and small end and a bit longer... obviously the JK rods and piston will put the piston over the deck at top dead center... so some experimenting (just because I have rotating assemblies from all VQ engines) to see if there was a piston pin height that would work from factory... DE piston is close (about .5mm too tall)... even if it did fit and would sit flush with the deck, the valve reliefs would be way too small (same as VHR)...

So today I took the crank out of an EYO 3.7 block and bolted it into an EYO 3.5 block, sits great!!! same piston height measurements as a 3.7 block further confirming that 3.7 and 3.5HR block is the same (at least EYO's there is another block variation for the HR but I don't have one to check measurements)

There is some pistons in work for this kit but they are 12.5 compression... IMO a bit high for street use (maybe an E85 motor) maybe take a few CCs out and be at 11.5-12.0 in compression but still would need to be conservative on the ignition timing, maybe if it gets popular an 8.5 compression for turbo cars could be planned

 

subscibed!!

 

At the same time a GTR crank fits into an HR block no problem (380RS)... except there is no boss for a crank driven oil pump (GTR uses a chain drive pump) and the snout is too long, now the GTR rods are 165.1mm and stroke is 88.4mm giving a rod ratio of 1.87... now the GTR uses a deck height way tall then the EYO block... so the plan is GTR crank (modified to use crank pump and cut shorter) + JK rods 151.8mm giving a rod ratio of 1.72 (worse than the DE's) now the AM performance cars use the 3.7 crank with 151.8 rods (1.76 rod ratio), and have lived to see 10k rpm... but the engine splits cranks down the main journals from the vibrations after 10 hours... ok for a multi million dollor race team paying $20k an engine.

As for a street use car... I propose VHR crank and rods with HR pistons (for clearance) into an HR engine, streetable cams S1s or S2s with 370z airboxes (to calculate the added air flow)... I am sure it will work without any additonal tuning of course some added tuning would help it.

For race car 3.5 HR crank with stock rods and a lightened piston can reach 9000rpm safely (with springs in the head of course) and let the beautiful HR heads flow!!!

 

I dont understand all that trouble to make the GTR crank fit.

 

Ive been looking into the GTR crank, I'm going with a custom dry sump oil pump(used Ebay) which will still be cheaper than a Nismo oil pump and moves the oil pump away from the crankshaft vibrations.

 

What are you doing with the car? Road race?

 

The GTR crankshaft is a stronger unit that has a higher nickel content. ie. Designed for high performance. Slight machining of the crank along with a custom piston( wrist pin moved up a few millimeters) and you'll have a 3.8 stroker for about $3500.

 

Just like doing what other say is impossible, honda guys have been doing this for years.

 

The 3.8 Stroker option is cool, but how many HR cranks have broken out there?

Cool find though.

 

HR cranks are extra stout but I'm saying GTR crank just for the extra displacement. If you go turbo then it's just extra insurance, besides 3.8 just seems much cooler than 3.7 .. The GTR is just more work but if it was easy then it would be honda civic.

 

Any more news here? On a website I saw a company is working on an HR oilpump setup to survive high revs. I would love a 9000 RPM redline.

 

Awesome concept, can't wait to see it come to life. Good luck!

 

It's been done. Very cool!

http://www.youtube.com/watch?v=WzFgDfMXxDU&sns=em

Pretty sure someone in so cal built these HR head VQ 37 motors.

 

That sounds orgasmic