Where do I find a single-groove crank pulley?

[barteet]

Hi, Everyone,

 

I was looking at the datsunzgarage.com website recently and he had an interesting sub topic on crank pulleys and their respective weights.

 

The lightest one was the single groove pulley, and I've looked at a few motors in junk yards but don't see these things thick on the ground.

 

I'm wondering if it's an L20 item? Anyone know?

 

Thanks,

 

-jeffrey

[RTz]

1) I usually find them on 240's. I'm also pretty certain there is an aftermarket company or two selling them. You might check with zccjdm.com

 

2) If you are doing it for weight purposes, I might advise against it, especially if you plan to spin the motor at high RPM. Generally, a heavy front damper and light flywheel/clutch is better for our L6's.

[primer&rust]

Search Ebay (cheapest), Summit Racing for Professional, or MSA for Products 80055 Nissan L-Series Damper. They are cheap, brand new, but be warned they are super hard to get these things installed because they are a extremely tight fit and probably should be machined to fit better. I messed up the threads on my crankshaft bolt torquing the pulley down and had to pick up another crankshaft bolt at the wrecking yard. I also bought some large washers at Lowes to help put extra pressure on the pulley to pull it down onto the crankshaft snout which helped alot. These pulleys also require a narrower belt than stock. If you get this pulley either get it machined larger or make sure you have plenty of time to get it installed and some big breaker bar to do the job or maybe air impact.

[1 tuff z]

as far as i knew the only oem single groove crank pulley nissan supplied was for the non-us market [second groove used to drive the emissions-air pump]. i sourced one from portugal last year after searching for a year or two. not inexpensive...

[TimZ]

2) If you are doing it for weight purposes, I might advise against it, especially if you plan to spin the motor at high RPM. Generally, a heavy front damper and light flywheel/clutch is better for our L6's.

 

I'll second that. While generally the info on that site seems pretty reasonable, the comment made about 1 lb from the flywheel = 10 lb from the car doesn't really hold for the crank pulley. This is because they are referring to the loss in rotational inertia that results from the weight reduction of the flywheel, which varies with the square of its diameter where the weight was removed. Because the diameter of the crank pulley is much smaller, especially where the bulk of its mass is located, reducing weight there will have a much smaller effect. Not really worth it if that's your only goal.

 

Now, if you are planning on making an engine that actually makes power above say 6000rpm, then an upgraded crank pulley might be worthwhile, but you need to get one that is actually a proper harmonic damper, not just a light pulley.

[Gollum]

I'd... third that? Anyhoo, I'd change to a single groove for aesthetic reasons long before performance reasons. Something that many people think they get and yet fail to properly implement (myself included in this statement) is weight in relation to leverage. A 20 pound rim can actually "seem" lighter to your car than a 25 pound rim with it's weight more around the outside diameter. Leverage leverage leverage. The crank pull as tim stated is much smaller than a flywheel, and won't have a huge impact. And as stated, you want something out front that will DAMPEN vibrations, not help them come out more!

 

All that said, if you're in the stock RPM range we're just splitting hairs aren't we?

[bradyzq]

Since I haven't actually looked closely at my Z's crank pulley lately, I'll cover my a** by saying this should apply to any old car and is general in nature....

 

Coupla things:

 

Sourcing ANY crank pulley from a scrapyard or donor engine means you're buying 40 year old rubber dampers. Sooner or later this will start to be a problem for all Z owners, regardless of the RPMs they're spinning at. So,IMO, a new damper/pulley is relatively cheap insurance. The original ones certainly don't owe us any more service at almost 40 years worth!

 

Same goes for the crank pulley bolt. I wouldn't buy a used one if I broke the original. I would spring for a new one.

[blue72]

be warned they are super hard to get these things installed because they are a extremely tight fit and probably should be machined to fit better.

 

I believe that problem only manifested itself in the first few batches they made. I ordered and installed the same Performance Products single row pulley about a year and a half ago and it slid all the way down the crank snout by hand, just like an OEM damper.

[m4xwellmurd3r]

I got one recently from Performance Products and it had to be sanded down with some emery cloth before i could get it to fit. First one was ordered from MSA and failed after 5 months of street use. A single email to Performance Products and I had a brand spankin new one at my door step, no questions asked. Same thing, it was a really tight fit and needed some sanding/etc to get it on, but this time no failure. (the first one's dampening material had seperated and caused it to start spinning round and round)It's a great part for the price imo, and Performance Products definitely care about making sure their stuff is up to standard.