I have a LQ9 6.0 that I installed a 236 duration Torq II cam and is in a 2001 GMC Sierra RCSB and was displeased on the performance and the idle sound. I used to have a Thunder Racing 224 duration and was a powerful cam and had a nice lopey idlebut not aggressive. Well I decided to pull the 236 cam back out and put the 224 cam back in and to my surprize I'm a tooth off on the timing gears. How wiil this affect the way it runs and idle. I was told it would have a choppy idle but it sounded tamer than my 224 and was kinda a dog until upper RPMs. I was told that this is because it's in a truck but could it have been because I'm a tooth off?? I'm at the point of removing the cam (it's all torn down) but have stopped until I get some answers. PLEASE HELP!!!

 

leave the cam in. re-adjust the timing and drive the truck. timing is KEY when it comes to any valvetrain set-up. make 100.000000000% sure that after you adjust the timing it's correct this time.

 

Will I notice a difference??

 

I think that may be a big cam for a truck, IMHO . but I would still put it back in and give it a shot, since you have it already.

 

Each tooth its of I believe is 8 degrees of timing. Maybe more. Probablty not safe witha big cam on pump gas.

 

I agree, why turn back now?

 

Well I re-installed it this time straight up but I'm into a bigger problem. I stripped the threads on the crank and now I don't know what to do??

 

Negative, each tooth is about 2 degrees.

How did you strip the crank threads, trying to put the pulley back on with the stock length bolt?

 

Well kinda, I used a longer bolt to start it but bottomed it out then I couldn't get it to come back out so I stayed on it with a impact until it did. The threads didn't look that bad but as soon as I installed the stock bolt and got resistance I stopped and pulled it back out and the threads looked chewed up. That's where I'm at now, I don't know what to do???

 

I thought it was 8 my bad.

 

Jermzz is right, ~8 camshaft degrees. 44 teeth on the cam sprocket. 360/44=8.181818

 

Timing is referenced at the crank sprocket, not the cam, hence the timing marks on the aftermarket crank sprockets. One tooth on a crank sprocket is 2 degrees. You are right on the one tooth on the cam sprocket being 8 degrees, but I personally don't think this guy is adjusting his timing using the cam gear. If he was 8 degrees off, bye bye valves/pistons.

 

The crank gear has 22 teeth. Where you getting 2 degrees? 360/22=16.363636

Cams are advanced & retarded by the cam gear. Cam makes 1/2 revolution for every crankshaft revolution. Therefore, a tooth off at the cam gear makes it 16.363636 degrees off at the crank. But when talking about cam advance or retard degrees, aren't we talking camshaft degrees? I used to be well versed in all of this stuff, but age has taken its toll on my memory, so I'm not 100% certain .... but should be close

 

For reference so we can look at something...


When we talk about advance/retard we are talking about how far the cam is actually advanced or retarded, but *most of us* adjust it using the crank sprocket for timing reference. I wish I could find the damn rollmaster instructions laying around here. I would take a pic and post it up.

 

Yes, you are correct that timing is measured in crank degrees. If the chain was off one tooth on the cam sprocket, it would be 8 cam degrees or 16 crank degrees. If the chain was off one tooth on the crank sprocket, it would still be off 8 cam degrees or 16 crank degrees. Youre thinking about adjustable timing sets, where each keyway is offset by two degrees. Just cause the next keyway is under the next tooth dosnt mean each tooth is 2 degrees. Dont forget that the crank dosnt turn when you turn the sprocket to the next keyway, you pull it off the crank snout and reinstall.

 

I was talking in reference to the timing marks on the adjustable crank sprocket which I thought was the issue at hand, not the actual degrees the cam is advanced retarded. Yea, bad approach on my part, my bad. 8 cam deg = 16 crank deg. Not negating that.

 

I thought my math was better then that

 

um..his last question was what to do since he stripped the threads on his crank snout. thats all good info, but I think we need to try to find him some info on if he can rethread or do something about re-installing his crank pulley. I dont have a clue, other then to maybe chase it with a thread chaser and us a slightly larger bolt.

Ski

 

I dunno if thats safe. If it can't be cleaned out to use the origional sized bolt he might be SOL. I've never heard of that happening before. If you cant torque it to spec the bolt will back out. Sometimes it backs out even if you do. lol.

Hopefully someone will chime in whos either had the problem or knows for sure. That would really suck if he needed a new crank.

 

So another crank gets fucked up with the longer bolt method. Way to go to everyone who still recommends doing it that way.