MADJAK's NA8 - 200+HP N/A

[speed]

That panel looks fantastic. Great job!

[949Racing]

Dropped in to to clarify a few things

The knife edged crank from us shown earlier in this thread was an experiment from 2010. Not a customers engine, just something we were playing around with. We ran it at 8500 rpm for quite a while before it cracked a main cap and spun a main bearing. The crank survived so we sold it to a shop friend and advised them to keep it under 8200. Since then we have stuck with minimal modification to the OEM cranks for all our engines, including customer engines. Al journals get micro polished, crank get deburred and balanced separately. For some a few special engines, we get the clutch assembly and balance the entire assembly with damper. We have found that the OEM crank is good for long periods up to about 8300rpm. With sustained revs past 8500, the life of the main bearings is reduced considerably. For that reason we recommend our billet crank option which has lived past 9500rpm in dry sump engines. The billet crank has 4 counter weights to the OEM cranks 8. The 4340 billet crank has a much higher modulus (stiffness) the OEM forged crank so it keeps its shape better at high RPM.

[zossy1]

Dropped in to to clarify a few things

The knife edged crank from us shown earlier in this thread was an experiment from 2010. Not a customers engine, just something we were playing around with. We ran it at 8500 rpm for quite a while before it cracked a main cap and spun a main bearing. The crank survived so we sold it to a shop friend and advised them to keep it under 8200. Since then we have stuck with minimal modification to the OEM cranks for all our engines, including customer engines. Al journals get micro polished, crank get deburred and balanced separately. For some a few special engines, we get the clutch assembly and balance the entire assembly with damper. We have found that the OEM crank is good for long periods up to about 8300rpm. With sustained revs past 8500, the life of the main bearings is reduced considerably. For that reason we recommend our billet crank option which has lived past 9500rpm in dry sump engines. The billet crank has 4 counter weights to the OEM cranks 8. The 4340 billet crank has a much higher modulus (stiffness) the OEM forged crank so it keeps its shape better at high RPM.

Thanks for the heads up. That's useful info - we only push ours to 8200-8300 so perhaps we could take more off... Maybe next time

[madjak]

Thanks for the extra info Emilio. It changes my plans a bit. With the Honda manifold I would like to pick the revs up from my current limiter @ 8300 to at least 8500 or more. I'll need supertech duals so it won't be until later in the year.

I have a spare engine that this crank will go into. If I go for something radical I plan on thrashing it in there first before moving it to my race engine.

What do you guys think about lopping off the 4 counterweights like the cast SOHC crank? I've heard of the SOHC cranks reving to 8500 and our crank is forged though I'm not sure if that means its much stronger. I'd probably also take a little off the other weights but nothing as drastic as the one referenced above.

In terms of bearing wear, given my previous bearing failure I'm doing an annual engine refresh at least in terms of bottom end and lifter clearances. The engine would probably see a max of 15 hours work so I can probably get away with a little bearing wear.

The engine is out atm...my rebuild last year used oem bearings as ACL weren't available. Given the oil pressure dips under brakes and the failure last year I wanted to have a look at the big end bearings. It all looked good and is now back together with ACL bearings and a DIY sump baffle. Next event is next Friday so I'll know then if it has helped.

[949Racing]

In national level SCCA road racing, 10-15hrs is acceptable life but we don't really cater to that customer. Most of our US customers are racing with NASA or other groups with different rulesets and want a much longer lasting engine. Never experimented with deleting counterweights. Let us know what you find out. In the end it's an undersquare enging with short rod ratio designed for max revs of 7500 (JDM version) so hanging out at 8500 is going to shorten the lifespan no matter what you do to it.

[madjak]

Its not all wired up yet but it's mounted in the car for this weekend. Looks very serious!

[Magpie]

Very serious!

[Apu]

Very impressive!

[rascal]

Nice job....

What is the keyhole used for next to the green light?

[madjak]

Nice job....

What is the keyhole used for next to the green light?

I'll be removing the key and steering lock from the column. The little key will be used for security and to disable ignition, injectors and fuel circuits without having to trip the main breaker say if I want to check the logs on the ecu.

[speed]

Prepare for take off!

[beavis]

Nice job....

What is the keyhole used for next to the green light?

I'll be removing the key and steering lock from the column. The little key will be used for security and to disable ignition, injectors and fuel circuits without having to trip the main breaker say if I want to check the logs on the ecu.

I use the removable steering wheel as my security.

[madjak]

Yeah me too... If I leave the car outside over night I also take out the ECU, and even if someone has all that, I'm pretty much the only person that can start the car anyway.

The key is handy though at events when I'm out at lunch or something. I don't want to carry around the wheel and there can be enough public around that it's risky leaving a car in the pits.

[madjak]

It was a good weekend down at Collie. I set a new PB on the track of 51.93. Also my new sump baffle is working well and stopping any drops in oil pressure under brakes. Here is my last run of the day:

[The American]

looks and sounds awesome! I've never been to Collie, but that looks like crushed limestone beside the track? I imagine the dust cloud would become reasonably epic in the event of a proper 'off'

I just googled Collie lap records - 51.93 is a very good time