Rb25 trigger kit and timing misalignment

[drifter17a]

Hey all,

 

I’ve got an RB25 with a trigger kit that includes a crank wheel, and I’ve hit a wall trying to sort a timing belt tracking issue. The belt either rides right on the edge of the cam/crank pulleys or walks slightly forward once the engine starts. It tracks okay-ish for a moment, then creeps right to the edge—and honestly, it’s stressing me out.

 

I’ve spent hours removing and reinstalling the belt, double-checking everything:

 

• Tensioner setup is good, checked multiple times
• Idler pulley and washers are all in the correct places
• Followed the RB25 timing procedure step-by-step

 

 

The only thing I changed was the rear crank washer—I swapped the OEM one for a Neato version, and it made things worse. The belt now sits even more forward than before. I’m beginning to think the crank trigger wheel itself (from the trigger kit) is the issue—poor design or slightly off dimensions.

 

What’s strange is that with the previous belt setup, it actually ran fine for a couple of years—around 4,000 to 5,000 miles, even with hard driving and high RPMs. But even then, the belt was always riding right on the edge, and I know that’s not ideal or safe long term.

 

At this point, I’m debating whether to:

 

• Machine a few mm off the crank trigger wheel to bring it back in line, or
• Replace it entirely with a better-designed unit

 

 

Only thing is, I already have the Cherry Hall sensors, bracket, etc.—I just want to replace the wheel only, not the entire kit. Anyone know a brand or supplier that sells just the crank trigger wheel on its own?

 

Would really appreciate any feedback—especially from anyone who’s run into this exact issue and found a reliable fix.

 

Thanks in advance.

[GTSBoy]

Are you suggesting that the kit did a cheap and nasty job of just jamming the wheel in between other things and caused the misalignment?

I mean, we normally do this with an integrated crank trigger wheel, not something bodged on. It's not 1995 any more.

[Dose Pipe Sutututu]

Post up some photos

[drifter17a]

The trigger kit I have is similar to the one in the link below. While going through Facebook, I saw someone else mention a similar issue, and I’m starting to think this could be related to the crank gear itself. I understand these parts are CNC machined, but maybe some earlier versions or individual pieces might have slight inconsistencies—it just doesn’t look right in my case.

https://www.facebook.com/share/16an8evZd9/?mibextid=wwXIfr

I originally installed the crank gear using the thin OEM washer, but as shown in the attached photo, the timing belt walks very close to the edge. When I tried using a Nitto washer—which is thicker—it actually made the issue worse. The belt walks about 1mm off the front edge, which raises more concern about alignment.

 

I’ve gone through the full process of elimination:

 

• The tensioner pulley and bolt are brand new and installed correctly. The bolt isn’t bent and is oriented properly.
• The back of the tensioner and the idler pulley are clean and seated correctly.
• The idler sits slightly more forward, which I understand is due to its design.
• I’ve experimented with both tight and loose belt tension, but it makes no difference. As soon as the engine runs, the belt immediately walks forward again—even if I reset it beforehand.

 

 

At this point, I’m considering replacing the crank gear with your Race Version 1 (12-tooth), but before purchasing, I wanted to ask:

 

1. Are you aware of any alignment issues when using this gear?
2. Would this gear help keep the belt aligned correctly, or could the walking still occur?
3. Does it work with a standard missing-tooth crank and rear washer?
4. Is there any specific crank setup or install procedure required?

 

 

For reference, I’m not using a front washer, as the PRP crank gear seems to replace the need for one.

 

Looking forward to your advice.