BNR32 Oil Pump Drive Issue

[240zdan]

I would like to add two very important considerations to this post before people go out tearing their cranks out and fitting collars. There would be two reasons to fit a collar. One is to widen the drive, another is to reduce the clearance.

Reducing clearance is bad. The oil pump gears cannot be stressed by a crankshaft doing its thing, this can cause oil pump gear breakage. Forget about the slop caused by running loose clearences breaking the gears. There will be slop regardless with a flat drive system if you have the clearences required for this faulted system. .005" extra slop isn't going to make or break the gear.

As far as widening the drive goes, that can do two things. Spread the drive load to the entire width of the gear, or spread the damage to the entire width of the gear. It all depends how balanced your bottom end is, the condition of your damper, and how high you rev.

Having said that I have been running a narrow drive that has seen 7500rpm and plenty of rev limiter for 7 years.I pulled the pump due to low pressure (loose backplate screws) my oil pump gear and drive looked perfectly normal.

FWIW heres a pic of an oil pump gear ruined by a full width drive The full width drive is NOT a solution, and not worth doing IMO. The full width drive still wants to spread the gears apart, moreso than the narrow drive as a matter of fact! Perhaps this is why Nissan engineers tried to narrow the drive on early GTRs.
The only way id pull the crank is to install a spline drive conversion. For now ill just keep my damper in check and make sure I don't rev past 7.5k

[FRRACER]

Above reasons are exactly why we developed the spline drive kits, eliminates the uncertainly and double guessing what RPM is safe to use on a given type of oil pump. The Reimax has very very loose clearance. The narrow drive contact patch would be a 1/3 of that length ways.

[tommytomatoes]

Above reasons are exactly why we developed the spline drive kits, eliminates the uncertainly and double guessing what RPM is safe to use on a given type of oil pump. The Reimax has very very loose clearance. The narrow drive contact patch would be a 1/3 of that length ways.

The reason Reimax use the clearance is to compensate for flex of the crankshaft at high rpms. How much clearance/play do your spline drive kits have?

[FRRACER]

Clearances on out spline drive setup are measured totally different and you cannot compare the two. We stress tested several clearances at different variations and came to fine one that worked best for us. Primarily when the back and forth chatter occurrs when hitting the limiter on the flat drive you will always have the pressure in the same spot and sooner or later this is where the cracks develop and fail. You also need to factor in cavitation which even occurs on the mother of all pumps - the Tomei one.

[Bruizer]

Darn, I have a Tomei pump... Guess I'll be rebuilding it sooner than planned. Hopefully it doesn't take out everything with it.

[MarusGTR]

Clearances on out spline drive setup are measured totally different and you cannot compare the two. We stress tested several clearances at different variations and came to fine one that worked best for us. Primarily when the back and forth chatter occurrs when hitting the limiter on the flat drive you will always have the pressure in the same spot and sooner or later this is where the cracks develop and fail. You also need to factor in cavitation which even occurs on the mother of all pumps - the Tomei one.

Got any more info on that cavitation phenomena? Its the first time I'm hearing about it for oil pumps. Water pumps, sure, that's what the N1 is for, but I didn't think you could vaporize oil that easily.

[Bruizer]

yeah, curious. These cars have been around for 26 years now but I've yet to hear much about that stuff. especially on the tomei.

[FRRACER]

Nothing new. cavitation does occur with oil pump and once with poor drive designs are easily affected.

https://www.highpowermedia.com/blog/...ump-cavitation

FYI mod works garage have been using our kits on all of their recent rebuilds and tuned engines with out any issues .. Not that there were going to be any but when you bring out new things that people do not understand or appreciate there is always that fear factor. We have shipped many of our spline drive kits to Canada it's one of our biggest markets.