Crankshaft harmonics?
 

Can crankshaft harmonics/vibrations cause anything to happen in the valve train?

Re: Crankshaft harmonics?
 

Yes it can.

Re: Crankshaft harmonics?
 

I'm wondering if harmonics had a hand in my rocker to valve wear.
That is another thing that seems to be specific to my motor. Others have run same cams and springs trouble free.

Re: Crankshaft harmonics?
 

Art, although you have a timing belt, the harmonics and frequencies will transmit to the valvetrain due to the lack of dampening from a crankshaft that lacks counterweights.
I believe that a crankshaft with counterweights and the right harmonic balancer will solve a lot of your problems.

Re: Crankshaft harmonics?
 

Even though the crank checked fine I'm going to put in a stock crank. I don't believe 8 pounds will hurt me that much. And maybe I'll get rid of these "one of" problems.
My other motor with less cam, less compression, and a stock crank. Responded to rpm a lot better than this motor. It was half a second between bracket mode and race mode. This motor was only two and a half tenths. That's shifting 1000 rpms short and running taller tires.
It might go quicker with the stock crank.

Re: Crankshaft harmonics?
 

Art, I believe you will not notice that much of a change in performance.
Nevertheless, if you want to get the best out of the crankshaft, I would suggest your crankshaft to have some weight removed and probably change the shape of the counterweight and have the lightening done properly.
My choice and recommendation is Shaft Tech:
http://www.shaftech.com/modification.html

Re: Crankshaft harmonics?
 

Thanks for that, but I think I'll just use the stock crank and leave the trick stuff for a new owner. I went to the Billy Nees academy of race car finance (actually he might have got it from me LOL). I don't want to spend $1,000 or more on a crank.
The whole car is for sale for $12,500 LOL

Re: Crankshaft harmonics?
 

Does your 2.4 engine have a separate balance shaft ?---Trevor

Re: Crankshaft harmonics?
 

It was removed. Just about everyone that runs a 2.4 removes them. Without any problems.

Re: Crankshaft harmonics?
 

Which damper you running?

Re: Crankshaft harmonics?
 

I started running an Innovators West. I took it off because I thought I damaged it installing it. I sent it back and there was nothing wrong with it.
Now I'm running a solid metal pulley. This is an inline 4 cylinder. Quite a bit different than a V8.

Re: Crankshaft harmonics?
 

Art, running a solid metal pulley is a recipe for disaster on a high RPM 4 cylinder engine, especially if you do not have counterweights and no dampening.

Here is a link with some good discussion on the subject:

http://www.eng-tips.com/viewthread.cfm?qid=107602

Re: Crankshaft harmonics?
 

Artie, I would see if I could get Raymond Martin, (Baytown Texas?) to talk to me.

Re: Crankshaft harmonics?
 

It's just that there are hundreds if not thousands of people running the same block and crank setup. Most are street cars and they use the aluminum pulley to underdrive the alternator. When racing they shift at the same rpms as I do (within 500 rpms). A lot make twice the power I make and three times the torque.
The one substantial difference is they are turbocharged. And I have to extract as much power as I can because of my lack of pressureized air.
I ran a crank with the counterweights removed. I'm starting to see that most if not all of my problems since I put this motor in the car. Might be traced back to the harmonics. My first problem was a broken stator support in the trans. Another problem that nobody that runs automatics and these motors had ever heard of.
The first motor I built was a mild (get to know the combo) verision. It ran trouble free for 2 years. And when I wanted to go fast it was shifted at the same rpms. With over 200 runs (a lot with improper fuel mixtures) the bearings looked like the day I built the car.
With the new motor the bearings allways looked weird (like there were oiling issues) in places that should not show issues. This was verified by this this time the rod bearings had only one easy run.