Timing Belt Options

[R32 TT]

Hi guys. I've just tried a new Gates Belt from Just Jap (Gates HSN 150T) but it doesn't fit. I have a Gates 152T but in the NEO compound (the 'weakest' of the Gates options) and this "just" fits - but I am concerned about getting the best material I can for the belt. Obviously don't want a failure.

Looking at the guide and doing searches brings up the Dayco 94407 belt. This is also 152T, 25mm wide. This says it is Chloroprene compound - so not sure how this compares in strength/temp to the Gates Neo. Does anyone know?

Then I found another Dayco belt, 94843. This appears to be 153T, 25mm wide and made of the HSN compound, which as far as I can make out is the 'best' compound. I've seen a few threads about people having a little trouble fitting belts at 150/152T, so maybe this 153T belt could be the ticket? It is certainly more expensive than the 94407, so hopefully this indicates it is the superior belt..

Any comments on this one? Anyone know their belt 'compounds' or suggest an even better belt?

Here's a couple of links on the two Dayco Belts:

Dayco 94407

Dayco 94843

Edited October 25, 2010 by R32 TT

[JonnoHR31]

why doesnt the gates belt fit?

[Fry_33]

I know that this is a little old but thought I'd at least give a quick reply..

NEO = Neoprene which is also known as Polychloroprene.

The different types of rubber compounds the belts are made of give the belts different temperature resistance ratings as well as oil resistances. You can also Nitrile, and HSN (Highly Saturated Nitrile). I would sat that you would want to at least match whatever the material of the standard T1040 timing belt is.

There's a number of ways to do the conversion so it all depends on the method you use as to which belt/compound option you have. I think that there were approx 5-6 belts that were possible to use for this. I'm just going off what someone else told me so someone here might be able to correct me on that.

[JonnoHR31]

the 150t belt from gates is for 2 tensioners in the standard locations, down the bottom next to each other.

the 152t belt needs the tensioner relocated as per the 30det guide. not sure bout the other belts

[R32 TT]

Whoops! Sorry guys, pretty average of me to post a question and then not reply...

Ok, Just trying to go back through my notes on what I found out back at the time.

Bottom line is, as JohnnoHR31 points out, the JustJap belt is for the two tensioners at the lower position. I should have known this from the start as I have read this before - but somehow I just read "suits RB26/30" and bought it. I will add though that the guys from JustJap were very good about it and happily refunded me the dollars not only for the belt, but also for freight - which I fully expected to have to pay for. Great service, thanks guys.

The belt they supply is (from memory) a Gates T306. This is 150 teeth x 23mm wide. It is in the HSN compound (which as FRY_33 points out) is the strongest, most heat/oil resistant compound.

For my application, with the higher mounted tensioner, I needed a 152T as per the guide. In fact for me (and some others) even this is a tad short. I used a 153T and it is the full 25mm wide and in the HSN compound. The part number for that is a Gates T317. The 152T version is a Gates T291, also HSN, also 25mm wide.

So bottom line is, when building one of these motors, you obviously want to put the strongest most reliable belt you can find on. Getting a 25mm wide is what you want, and getting an HSN Compound is 'better' than the Chloroprene compound. Both Gates and Dayco offer belts in both types of compounds - so be aware that you should check this out as well as the number of teeth/pitch etc. And for those of you struggling to make a 152T belt fit - there is a 153T !

Cheers

[webber]

If anyone who is interested i have some Brand New Gates Racing Rb30 Twin Cam Timing Belts (150T for std position tensioner / idler),

Cheers

[chairman]

which belt do use if u run both tensioner above water pump ? as this block doesnt have flat machiend spot