What's the difference between polyeurethane and nolathane bushes if anyone knows or if there is even a difference :-s
And which is better???
Cheers

Afaik all urethane bushes are approximately the same in terms of strength/longevity. AFAIK 'nolathane' is just a trademark/brand name - a bit like how 'disprin' is a brand name of one of the various 'aspirin' tablets on the market.

Alledgedly there were some on the market (and I can't recall which brand) which were made slightly differently and were a bit softer than regular urethane bushes, but I've never heard of anyone actually saying that that was their experience in practice - (i.e. it seems it may have just been a marketing thing)

The 'usual' advice applies. Urethane in general is sturdy, but it has very little 'compliance' (or more simply, it has less 'give' or ability to be squahed etc.

As such, this material works absolutely BRILLIANTLY for suspension bushes that are more like a 'hinge' and only rotate around on that bush - like inner control arm bushes on the dattos. Leaf spring bushes too (for the most part).

But when they need a bit of give, because the suspension part inside them is moving at an angle - not like a hinge, but like the castor bar/castor bar bushes - then they don't 'really' have enough compliance. Depending on your luck (and just how much of an angle they are subjected to on a regular basis) and how sturdy the castor bar is, this _can_ see you eventually splitting teh urethane bush. On minis (and I've mentioned this before) they can actually chew through the (already borderline, and some 40 years old or more) castor bars. But on the minis, rubber just didn't last long enough.

Interestingly it was the front half of the castor bar bush that always tore up well before the rear. And so some clever fellow (and it certainly wasn't me, I probably wouldn't have thought of it in 10 lifetimes) tried something - they got a set of rubber and urethane castor bar bushes, and fitted the urethane halves to the front, and the rubber to the rear. This allowed 'just enough' compliance to keep the caster bars happy, and the urethane at the front halves stood up well over years of use. I've taken that trick and applied it to the datsun (and some other cars).

Similarly valiant upper control arm bushes - the bolts end up on angles vs the bush as that is how they adjust the upper arm position to dial in camber and caster. SO use of urethane on the upper bushes will see them chewing out the bush, or the bolt, or even cracking and tearing the control arm locating bracket off the chassis rail/inner guard (it was already a weak spot on the vals, and urethane bushes make it doubly so)

Now theoretically if you made really short castor bars to dial in something (random figure for sake of argument) 15 degrees of positive caster, that would put the control arm at enough of an angle with the bush/bolt that it would tear something over time. But within the range of realistic caster settings you'd get on any streeter (even one that sees some occasional track time) it shouldn't be a problem at all to run them for the control arms.

In the rear, it can vary from car to car. What's not usually initially obvious with leaf springs is that if one wheel rises, then the diff is not only compressing the spring on that side, but it's also trying to twist both springs on an angle (when viewed from the rear of the car). This will obviously be resisted to some extent, and as such, leaf springs have a sort of 'built in' sway bar effect. If you hypothetically converted a 1200 to 4 link rear suspension, (and various weights and geometry was done to be identical to how teh axle would travel/move with the leaf sprung rear) and the same spring rate, you'd actually have slightly different handling as you'd lost that effect. Reason I bring that up is that replacing the leaf spring bushes with urethane will increase the sway bar effect. I don't want to cause panic here, the effect isn't astronomical, just thought I'd add it for trivia.

One last thing - I have never heard of it being the case on any other vehicle, but I do know that a while back (probably over 10 years) there was a brand of urethane lower control arm bush for valiants that had the inner diameter too large. Not by a mile, but perhaps a millimetre or so. It would physically 'fit' together but it allowed enough movement, that they were in fact worse than most 5 year old rubber ones. The problem with them is that if that bush falls apart (or has too much play to begin with) it allows the control arm and torsion bar to move upwards on the val, and it will rub the drag link. This then wears down the torsion bar, so you end up with softer spring rates. One of the first things to do when looking at any used torsion bars (when sourcing later/v8 spec bars to stiffen the front a little) is to check them carefully for that tell tale wear sign.

So after all that, bottom line - generally it'd be rare that there's much of a difference brand to brand, and beyond that, give some consideration to where they will be fitted. If it's a hinge joint, like control arm bush, or sway bar D shaped bushes, they are fantastic, if it is for something that flexes/angles (not a hinge) like castor bar bushes, then urethane is not so ideal, but quite possibly a half and half setup could be had. (btw I did them in the datsun about 2 months back, and the rubber halves were dirt cheap. The urethane ones a little more, but not 'risking bankruptcy'

I use Pro Bushes (brand) over nolathane.
They do have a small degree of compliance,
and have good grease grooves moulded in.
Make sure to use plenty of the lithium based grease on all surfaces and the through bolt.

Awsome thanx for all the info !!!! Really helps cheers

So would you say this holds?

For comfort, use original Nissan bushings

For racing, use urethane (e.g. "poly", Nolathane or Delrin) for:
* LCA bushings
* Leaf Spring end bushings
* Anti-sway bar D-shaped bushings
For racing, use rubber for
* Anti-sway bar end bushings
* Tension Rod bushings
* Diff pinion snubber
* Strut bumper
* Shock bushings

pretty much yes. Thanks for posting that - as I totally left out bump stops (like on the pinion, but also, more broadly for all cars of all makes in general any bump stops - some control arms have them - of course we're mainly looking at the rubber bump stop on top of the strut tube/insert, which basically is the same thin don a different way)

Tension rods/caster bars/brake reaction rods (there might be other names out there for them too - anyone care to add to that?) CERtainly rubber for 99% of cases, but I'd again suggest the half and half option for that specific bush/component.

I suspect a good 'case' could be made either way for leaf springs. Whilst most would tend to go urethane all round on that, one might also look at using a urethane bush at the front leaf eye hole, since that takes most of the load (esp when the car is moving - the rear wheels 'push' the car forward through that front leaf eye bolt. The rear eye/bolt is (relatively) less stressed - along for the ride, at least as far as drive forces are concerned (still obviously gets put under stress with suspension compression/holding the car off the ground) Running rubber bushes for the rear leaf eye etc, might give just a bit more compliance. If tht is the case, then rubber vs urethane could be experimented with. The difference here would be that urethane all round would have more resistance to body roll/twist of the leaves - so it would have slightly more of that 'pseudo' sway bar effect. Rubber rear bushes would be like a little smaller diameter sway bar equivalent effect. So it could be used, theoretically, to alter corner exit (in particular, but also mid corner) oversteer.

Our tech article Tension Rods says this, so I added 'reaction rod':

Quote:

Speaking of bump stops for the front struts, I have just realized that my '81 B310 does not seem to have any. Are they missing or did the car never have them? I am accustomed to seeing the later front wheel drive [B12, B13 etc.] cars using the one piece bellows with the bump stop molded into the top of it. My B310 uses a rubber bellows but it is sandwiched on top of the coil spring and incorporates no bumper.

My question is, if someone were to badly bottom out the front suspension on a B310, what would keep the strut shaft from bottoming out in the insert and being damaged?

Has anyone ever added a conventional bellows/bump stop from a later car? I have an extra pair of rear strut bellows from the rear of my B12 4WD wagon that seem to fit perfectly.

Mike

Your struts may have more compression than your suspension is capable of, if so no worries. I'm not sure if stock Datsun KYBs are like that or not.

The "bound bumper" fits up at the top of the piston shaft and may not be visible after installation. Here's the B110 unit, the B310 unit is similar but the bumper is beveled on one edge. #2 in this photo:

Thanks very much David. My car does not have the [number 2 in the photo] bound bumpers. I am installing a pair of n.o.s. Koni strut inserts and will use the one piece Sentra bellows and bumpers.