torquing camshaft sprocket bolts without damage?

Hi All,

I'm putting on new camshaft sprockets and wonder if anyone has any tips for how to secure the shafts during the bolt -torquing process. I'm afraid of damaging the lobes if I put them in a vice. Or maybe I should tighten the bolts with the camshafts installed in the engine using tension from the cam chain? I don't know, these are precision parts, I don't want to F it up.

Thanks!

Don't install the sprocket bolts tightly until the cams are in the motor, and everything is timed and set. It's the last step.

Normally, I will have the sprockets attached with the bolts loose when I put the cams into the motor. Then I will remove the sprocket bolts and let the sprocket slide down to the smaller diameter area of the cam shaft. That way, it's real easy to walk the chain over the sprockets to get the timing right.

You get the chain and sprockets timed correctly (with the camshafts approximately in the right postion for 1-4TDC), then slide the sprocket and chain combo onto the camshaft's sprocket hub. Then rotate the cam slightly to get the bolts to line up. Once this is all together, the chain and camshaft will stop the sprocket from turning enough to torque the bolts. If not, then it's real easy to put a wrench on the crank to stop it from turning. If it seems like it's still hard to stop it from turning, then you are likely using way too much torque. Since it is now timed, you can rotate the crank to get to the other sprocket bolts.

Remember, you can have the tensioner in place and tensioned while doing this, but release it before installing the valve cover. I'm sure you've seen the warning, but in case anyone is reading this:
home.comcast.net/~loudgpz/GPZweb/CamsKZZ...KZZXZR550500400.html

...and use some threadlock, there is a guy here who had those m6 bolts let go on a ZR550 and wrecked a valve.

I'd also use new high tensile steel m6 cam cap allen bolts, cheap enough new and old ones can stretch and can break. Use threadlock and tighten by feel when you have set the cam timing, not with a tourque wrench imo. In my old days i have broke a few of these with a manual and big tourque wrench and it is really difficult job to extract a broken bolt from here. Most big tourque wrenches for cars and head bolts etc even if calibrated are pretty innacurrate at low settings .

Tyrell Corp wrote: .......... In my old days i have broke a few of these with a manual and big tourque wrench and it is really difficult job to extract a broken bolt from here. Most big tourque wrenches for cars and head bolts etc even if calibrated are pretty innacurrate at low settings .

For sure, if a torque wrench calibrated in FOOT pounds is used there will likely be a problem. Even the very best torque wrenches are not accurate below 20% of their upper range, so using a FOOT pound wrench and converting INCH pounds to FOOT pounds normally will cause a problem even if the conversion is done correctly. The only torque wrench that should be used on those cam cap bolts is one that is calibrated in INCH pounds, and even then, the specified torque must be in the 20% - 100% portion of the wrench's range. Ed

Just the info I was looking for, and more, thanks very much!

Tyrell Corp wrote: ...and use some threadlock, there is a guy here who had those m6 bolts let go on a ZR550 and wrecked a valve.

Alas, that was me; still trying to clean up the mess. I'm actually wondering if I should loosen the sprocket bolts off the sprocket didn't fall off and retorque just them to make sure that they're OK. I'm just a afraid of breaking a bolt if they did, in fact, use thread lock on that one.

I've always found all of those parts to be very strong and never had an issue with just using a nromal torque wrench. I think it's important to get every bit of old threadlocker off the bolt as it may prevent proper threading later... not to mention little bits of the stuff dropping into the cam chain tunnel.

loudhvx wrote: Don't install the sprocket bolts tightly until the cams are in the motor, and everything is timed and set. It's the last step.

Normally, I will have the sprockets attached with the bolts loose when I put the cams into the motor. Then I will remove the sprocket bolts and let the sprocket slide down to the smaller diameter area of the cam shaft. That way, it's real easy to walk the chain over the sprockets to get the timing right.

You get the chain and sprockets timed correctly (with the camshafts approximately in the right postion for 1-4TDC), then slide the sprocket and chain combo onto the camshaft's sprocket hub. Then rotate the cam slightly to get the bolts to line up. Once this is all together, the chain and camshaft will stop the sprocket from turning enough to torque the bolts. If not, then it's real easy to put a wrench on the crank to stop it from turning. If it seems like it's still hard to stop it from turning, then you are likely using way too much torque. Since it is now timed, you can rotate the crank to get to the other sprocket bolts.

Remember, you can have the tensioner in place and tensioned while doing this, but release it before installing the valve cover. I'm sure you've seen the warning, but in case anyone is reading this:
home.comcast.net/~loudgpz/GPZweb/CamsKZZ...KZZXZR550500400.html

One thing I'm not clear about this - at what point am I installing and tightening the camshaft caps?

Getting close to riding again (hopefully)!!!!!

That is done when you install the cams, basically the first step, roughly near 1-4 TDC. In the above quote, it is assumed this is already done. But the sprocket is still loosely attached at that point (so you can roughly tell where the timing marks are at), and the chain is not on the sprockets, and the tensioner is loose. You don't want to fight the chain while installing the cams. It's enough of a juggling stunt to get the camshaft lowered into position evenly with the cam caps.

By the way, get yourself a 10mm nutdriver, or nutdriver attachement for your 10mm socket. You should never need any more than very light torque to seat the camshaft. If a bolt binds, then you are doing something unevenly, and need to start over, or back out some of the camcap screws.

Since we're on the subject... make sure to wick out all of the oil from the cam cap bolt holes. Make sure there is nothing in any of the holes. Oil or sealant in the holes is what promotes stripping the threads. This is also especially important on the valve cover bolt holes as well.

Sealant and oil do not compress, but also don't have any friction against the bolt, so it makes the bolt feel easy to turn, but the bolt cannot go into the hole... thus it's instant thread removal.

In case you read that before I was done editing it, I added a few details.