Dougs951S

Guys, I need help getting the right rollers to do my timing belt. I have a bit of a bastardized car as some of you may know and while the car has never had an issue in the belt department *knock on wood* I dont think I have the correct rollers on it. My water pump is getting a bit noisy too so I'm thinking its time to redo the whole front of the motor. Car is an 86 engine, maybe ( I really don't know, and I'm the one who built it! ) with the updated water pump and 46mm idler roller. I'm looking to replace just the 2 balance shaft rollers and the timing belt tension roller since they have never been done under my ownership. I may replace the 46mm idler roller too if I determine it needs it. Besides the larger idler roller, what is the difference between early and late 951 roller kits? How can I find out what rollers I need? I'll be resealing the front of the engine while I'm in there as well. One last question, if I'm using an oil only cooled turbo, can I run a late N/A water pump for simplicity? Thanks in advance.

Edit: I see on the late 951 roller kits, one of the rollers ( not sure which one by looking at it ) has the bolt hole centered, whereas it is offset on the 86. Which roller is this, I will check it out in the morning and know for sure? What was the reason for this seemingly minor change? Also, what is the cheapest place to buy the rollers? Pelican only stocks some of them.

cruise98

The cam toothed roller is different between the early and late cars. Did you leave the stud or drill for the spring tensioner ?

Dougs951S

My car does not have the spring tensioner, so it must be an 86 block as I thought, and I do of course have the correct rollers on it. Thanks for jogging my memory of that little detail! When do people typically replace the 2 cam and 2 balance belt sprockets? Mine seem fine, I'm just curious If I should as it would add considerable expense to an already 450+ dollar job.

cruise98

I would inspect them. They do not seem to last very long. If they are rough, freewheeling or wobble, replace them. They do add up, but it is cheap insurance really.

Dougs951S

sorry I wasnt clear, when I said sprockets I did not mean the 4 rollers that typically come in a kit. I literally meant the sprockets, the 2 that are attached directly to the balance shafts, the one attached directly to the cam shaft, and the crank shaft sprocket. I will definitely be replacing the 4 rollers regardless, but it was my understanding that people did not typically replace the sprockets as they were just toothed cogs keyed to a rotating shaft.

cruise98

They are not a typically replaced part. Unless you run sans belt covers and spend a lot of time on Daytona beach, you are probably good.

Turbo17

As an aside, when I first did my belts, I read that the studs were a risk - particularly if the nuts holding the rollers on the studs had been tightened/loosened without proper countertorque.

Somewhere I saw the grim results of a busted stud that allowed the TB to come loose on our interference valve engine. With that in mind, and the recommendation to replace the studs that accompanied that story, I tried to find them.

Most were NLA or out of stock. Eventually I found someone who could special order them from Germany, but it didn't seem to be a common item that was regularly replaced during this job, so I left them alone. (I hate studs, having fought broken ones too often.) Does anyone here regularly replace studs that the rollers mount on?

Dougs951S

I think they should be fine, but I've heard advice to put a bit of blue loctite on the nuts, which I will be doing this time around. I did the belts about 18 months ago, but didn't do the water pump which I am now regretting. I figure this time around I'll do the job right which is rollers, belts, water pump, and front reseal. Then I wont have to worry about it for 3-4 years. I've heard that most people only replace the rollers every other belt job, so they should last 6-7 years. I'm also going to be installing an offset woodruff key this time around to advance my cam 4*.