Building the Nissan R35 GT-R VR38DETT For Safe Bolt On Power!

Howard applies engine oil to the bore to give the rings and piston some initial lubrication the first time the engine is started.

The crank has already been positioned and the bearings and engine bed plate installed.  Because it’s hard to align bore a bedplate which the VR is equipped with as opposed to main caps and this is a simple quick limited power build, we opted to use the stock torque to yield main cap bolts as opposed to studs to reduce the main bearing bore distortion. With this sort of made specifically for the bore size ring compressor, the pistons go in really easily with no need for tapping.

The rod bolts are torqued down and the bolt stretch is verified via a micrometer.

Now the engine short block is assembled!

We used ARP head studs since we had them.  For most simple motors like this, the stock torque to yield bolts are plenty strong enough.  The stronger studs and higher tightening torque cause upper bore distortion as well as valve seat distortion.  This must be compensated for in machining. Also, the unyielding studs can cause really high clamp forces as the aluminum block expands at twice the rate of the studs.  Because of this we only tighten the studs to the high end of OEM spec in an engine like this.

Howard drops the heads in place. We had subjected the heads to a fresh radius valve job using a Newen CNC valve seat cutting machine.  These valve seat machines also do a great job of matching the seats to the valve bowl and the radius gives great flow.

10 comments

  1. i had always heard that Nissan engines, particularly the RBs, were underpowered in comparison to how robust they were. Those days, apparently, are long gone when we get 500+ HP out of bolt-on upgrades.

    1. Less surface area to maintain the oil film so less pressure needed before getting bearing wear. Good oil flow and pressure can somewhat mitigate it.

  2. Very nice article, really accessible, will there be updates?

    Also, I couldn’t help wonder, was there any discussion about the downpipes getting coated? Did any other goodies get thrown in “since you were in there anyway?”

    Been a reader since SCC and still miss that magazine!

    1. Other than the PC9 coating on the pistons, the parts were kept mostly stock. This was a customer car and they just wanted their car back. Though it may not seem like a lot was done, the total gets up there pretty quick thanks to the GT-R tax.

  3. Great write up guys. Just to add some context:

    The original motor was stock with about 90k mi on it, most of which was spent with the boost up for WOT on E85. It was not in fact bad gas that lead to failure but rather an accidental downshift at WOT which resulted in a low RPM load on the OEM rods. If that had not happened, my guess is the engine would still be alive. That tune had a reduction in torque as mentioned in the article. But even with the motor build, that mistake should not be repeated. if you have a GTR – don’t let that happen!

    The owner just dynod the new setup and the results were impressive with the stock turbos. The head work appears to have netted a consistent gain in TQ across the rev range; but more impressively the peak TQ RMP was lowered by over 700 RPM’s down to 3,500 RPM’s.

    Great build guys. Hi Howard, Mike and Martin.

  4. I’ve really loved all of these modification articles / videos on the project GT-R. I was wondering if you would be making a video comparing the modified car’s performance to a stock car? Maybe quarter mile, 0-62, and a few laps on a track or Auto-X?

    I think it would be really great to have some sort of benchmarking so that owners will know how the mods improve the car in more sure terms.

    Thanks,

  5. could you be so kind to share you piston to wall clearance along with main and rod bearing clearance. this seems to be a very secretive issue when it comes to building a vr38 motor for about 1200hp or so.

Leave a Reply

Your email address will not be published. Required fields are marked *

*
*