Rb25/30 Timing Belt (A New Way)

[Wetherhead622]

Hello every one . I'm new to the rb25/30 build . I have that shit block that makes it hard to run the timing belt. ( no flat surface . I got the top tensioner Drilled and tapped . I know if you run it the normal way with the new location It's a 152 tooth belt . And run with the other way a 150 tooth belt .

I put a 150 tooth belt on with just the top (relocated tensioner) with no left one . It seams to work fine ? Car starts and runs the timing marks line up and that .

My question is has any one tried this ? And is this a possible way to run this set up

[Ben C34]

Nissan could have done that with the rb25 and choose not to.

I think the belt would slap around too much

[Shoota_77]

As Ben says it leads to a very long section of unsupported belt. Under normal circumstances you probably won't notice anything but if you're pushing for big power you might end up with bad timing fluctuation due to the flapping belt.

A Ross Balancer and Crank/Cam sensor setup may fix this though. For a measly couple of grand....

[Wetherhead622]

Thanks for the reply . The motor won't be pushing over 300ktw

Im going to get the slo mo camera if looks ok I'll run it and if it flaps round I'll changw it to a diffs to set up

[jiffo]

No idler on the Toyota JZ engines, although they have a much more heavy duty tensioner system.

BUT…..they run a proper cam and crank angle sensor, not like the thing Nissan runs from the exhaust cam.

I have a theory that Nissan only fitted an idler as they were experiencing too much timing scatter.

Fitting the extra pulley halves the belt harmonic to a level acceptable for most RPM applications.

If you're not using an idler, I'd investigate fitting a JZ tensioner instead of the fixed Nissan design PLUS look into a Ross or similar crank trigger setup.

[Shoota_77]

I've just put a tensioner on either side with mine. Hoping that is enough to be able to maintain tension either side of the crank. I wanted to try another tensioner (3 total) at some point in the belt but doesn't seem to be room. Time will tell if it works ok.

[Wetherhead622]

I'll have look in to the 1jz tensioner as my friend is rebuilding one . I just trying to find a better way to run the belt. As I can't run the lower lide pully

[Ben C34]

It's not like you are actually looking for a better way, you are just looking for one that works in your case

Can't you just get the correct block? Have you seen when guys have made a plate to go where the idler should be?

Edited October 27, 2014 by Ben C34

[Wetherhead622]

I ended up testing the way . I found that it had a little bit of slap as some said it would . So I now have changed to a new way again it seams to be the best way for me . I would change blocks but the motor is in the car . Thanks for every ones help

[Ben C34]

That's better.

Ages nizpro did a similar setup with both idler and tensioner above the water pump. I think auto speed has an article on it still.

Edited October 28, 2014 by Ben C34

[Na boy]

I made a plate