Crazy custom timing chain tensioner

[Dan Baldwin]

Long/short:

If this device keeps the chain stable at 9k, at reasonable levels of pretension, then obviously my reservations were unfounded!

 

Jeff, are you using one o' these?

 

I've never stroboscopically checked my cam timing accuracy at 7.3k, but with the stock guide it does make good reliable power up there. Of course, I doubt if I would notice even +/- 3 degrees with my measuring methods...

 

A question:

Does everyone install the stock curved guide with the chain pretensioned, or leave some slack?

[jeffp]

Hi Dan, well yes I do have one of those tensioners. I like the design, I have looked over the method and spacing of the idlers, which had had a mod done to them to move the top idler/adjuster down about an inch. I am going to run it on the car myself. I NEVER liked the stock tensioner on the engine, and I am sure my cam timing was changing.

The assembly, when installed on the engine tensiones the chain perfectly, and the thing I was really impressed with was the fact that I could push the tensioner tight with my finger, the chain was tight everywhere, but not to tight if you know what I mean. Then I turned the crank with an indicator on the cam lobe, and there is no slack, play in the cam operation. The cam moved exactly with the crank, I couldn't even get it to lag the crank by one degree. That is good enough for me.

[Tony D]

Yes, and to answer the question that begs to be asked on our Bonneville 2-Litre "Why not just use an S20?" we would LOVE to do that, it can make the 320HP and give us the speed we need easily, unfortunately the rules for "production class" dictate that 500 examples of any given model used in competiton had to be available within a production year, and alas the 432 would not qualify. Otherwise THAT would be the direction we would go.

 

So as it stands, we wait to see what this does on the dyno, and hope the cam stays put for those runs at least. If the power is not there, it will be a short season in G-Pro... >:^(