The Heart of a Record Breaker II:  The Doctor Is In

by Chuck Johnson

In our last story, we covered the basic design of our land speed record breaking engine we've dubbed the SR15VET 20V.  This time around, we'll take a deep look inside the engine and detail its build with none other than our resident Nissan guru, Nick Hunter of 5523 Motorsports.

nick hunter, 5523 motorsports

We like to call him the zombie vampire because we're ass clowns who find the need to humor ourselves at the expense of others.  Put all the ass-clownery aside though, take a deep look into Nick Hunter's track record of building Nissans, and you'll quickly understand how he earned his real nick name "the 23 Doctor."  (Translating 2-3 into Japanese you get ni-san.)  Nick's nickname (no pun intended), was initially earned through his experience repairing thousands of Nissans as a master tech at a local Nissan dealer. However, the nickname was quickly solidified through the multiple VQ35DE race engine builds he executed for Grand Am race teams as well as the likes of Dai Yoshihara and his Abu Dhabi drift car.  Throw in the slew of SR20DET, RB26DETT and VR38DETT street car builds he has executed over the years and there's no need to justify the nickname any further.  Let's take a look at the Nissan Doctor in action.

It just so happens that Nick Hunter was one of the first in the US to figure out how to install a SR20VE head on a SR20DET block.  Although most everything lines up, there are a few things that need to be addressed to make the SR20VE head swap happen.  Since the VVL head doesn't line up exactly with the RWD SR20DET block, plugging this drain hole in the block is one of the modifications that needs to be made.

To accomplish this, Nick Hunter drilled out one of the factory oil drain holes in the block with a 45/64 drill bit and then used a ½-14 tap to thread the hole. Nick then threaded a stainless steel plug in place.

Upon receiving the engine block back from the machine shop, amongst some of the many things that Nick Hunter measures and verifies, is the flatness of the block's deck along with the bore diameter and cylindricity.

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Dan DeRosia
Dan DeRosialink
Monday, October 21, 2013 7:18 AM
Huh; the 54C main bearing and groove behind them reminds me of the evolution if the Mazda 13B main bearings to having similar holes and backup grooves.

The VE build is interesting stuff; be looking forwards to more.
Monday, October 21, 2013 7:51 AM
I thought I remembered something from the Dave Coleman SCC days when he had to underdrive the stock water pump due to cavitation or something. I assume this is either not the case on your motor or it has been resolved.
I'm always amazed at the Frankenstein-ing we can achieve. Especially with Nissan stuff. My Datsun 510 has parts from more cars than I can count. Or maybe I should start counting :)
Chuck Johnson
Chuck Johnsonlink
Monday, October 21, 2013 9:13 AM
Jeffball610- Coleman is experimenting with shrouding the impeller wheel like a a turbo pump. It's yet to be proven or tested at this point. On this motor, we stuck with under driving the water pump with an oversized WP pulley.
Monday, October 21, 2013 10:48 AM
Any issues with the undamped crank pulley? I know the debate has been raging for years.
Chuck Johnson
Chuck Johnsonlink
Monday, October 21, 2013 10:57 AM
I think issues vary engine to engine, with some engines being more vulnerable to crankshaft harmonics. The BP Miata engine seems to be one of those that can't tolerate an undampened crank pulley and will lose a bearing quick. On the other hand, I've run billet crank pulleys on SR20's for years (including SE-R cup cars) and haven't had an issue yet... this was with the stock crank though. Since this crank was destroked, we ended up running a modified ATI damper before speed week. I think the G Spec unit is still a good solution for the factory 86 MM crankshaft guys doing a VVL swap.
Monday, October 21, 2013 12:22 PM
There is definitely an impeller design change for 2001+ RR SR20DE. Not sure if Nissan has rolled up the part numbers for the older SR20. We've been using this pump with good results in the NX.
Monday, October 21, 2013 12:24 PM
Oh, and the OEM RR SR20DE MLS Exhaust manifold gasket. No more scraping!!!
Chuck Johnson
Chuck Johnsonlink
Monday, October 21, 2013 12:50 PM
I believe we are using an exhaust manifold gasket from an S15. Its similar to a the RR gasket but with more layers.
jonathan thiffault
jonathan thiffaultlink
Monday, October 21, 2013 5:01 PM
I build a ae86 with a sr20vet, and i use that g-spec crank pulley and spacer, i dont know why but after something like 5 or 6 events, i explode my brand new sr20vet oil pump, do you think it can be because of the harmonic that come from that pulley that doesn't have damper. You know, the oil pump is mount right on the crankshaft. a lot of people on forum told me that but i dont really know, what do you think
Tuesday, October 22, 2013 7:54 AM
chuck - yes, S15 SR20DET exhaust manifold gasket

Jonathan - yes. the issue you are experiencing is a result of uncontrolled harmonics. the powered metal G rotor gears are susceptible to cracking even with a proper balancer, but add to that no balance and high RPM and you have a recipe for failure. this is a topic of heated debate, and i've got my own theories that i've proven and disproven over the years which i'd be happy to share, however i'd like to do so in a different forum. maybe chuck can help me with this (... hint hint... we talked about that idea i had the other night! :/ )

dgerrys - nissan still offers the original 53J water pump. the impeller did change for the roller motor, but i don't believe that nissan ever did a pump with a backing plate for the SR20 (the N1 RB water pump uses a backing plate, but i've never seen a factory offering for the SR).

dave colemans modified pump is sitting on a shelf at my place... still waiting to be tested! that being said, underdriving is super important on SR20's when operating at higher RPM's. a pressurized cooling system would solve this issue, but i can't recall anyone attempting this.
Wednesday, October 23, 2013 11:58 AM
Ohh man I can't wait to tackle this swap.
Saturday, October 04, 2014 8:53 AM
Did you guys bore up holes for CYL #1 in the headgasket or any other alterations to the headgasket prior to install to improve cooling for #cyl1 ?
current discussion in my build is whether if we should make a slightly smaller dia hole that whats on #cyl2 on #cyl1 or not.
Saturday, October 04, 2014 9:33 AM
The headgasket we use is from the T30 Xtrail GT (SR20VE) and it is unmodified. I would strongly recommend NOT adding any holes around the #1 cylinder. Think about the coolant path through the engine - pump feeds the front of the block, water is then forced to migrate towards the rear of the engine and then is fed through the gasket into the head which discharges at the front. The later model headgaskets tend to have holes added on the exhaust side of each cylinder as you want fresh cold water to cool the exhaust side of each combustion chamber, but the SR cooling system is poorly designed to begin with so making changes without having an engine to possibly write off for testing purposes is probably a bad idea!

That being said, this SR15VET is using a stock RWD pump, stock T30 MLS headgasket, stock head bolts, no thermostat, and a KOYO radiator WITH NO FANS; and it will only get hot (above 200*) if it is allowed to sit stationary after a few dyno pulls or a high speed run. even then, if you hold the engine speed around 2000 for 30 seconds, water temp will start to drop.

hope that helps

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