Vibrating problem

[soulman67]

Heres the problem, it will vibrate and shake for a few seconds then run smooth for a few seconds constantly from idle to highway running speed it stays at the same rythm. The truck hasn't lost power, doesn't knock or smoke. The truck is a 96 K3500 6.5 TD auto with 220k miles, I wondering what yall think is wrong with it.

[Bnave95]

Not much to go on with your details.
Is this at first start? Does it just at idle(cold) or just does it now and then at idle once warmed up?
With the miles you have and not knowing the history of your truck we could through alot at you.
Any chance you could give more details on what you know about your truck? What has been done in years past?
Things you have done?

[soulman67]

Well I found out what my problem was, the harmonic balancer spun off the crank. It took a cunk off the end of the crank too. Looks like I need a new engine or maybe I'll build a wild 6.5

[redbird2]

I build my own for my truck, I've had better luck with it that the rebuilds I've been install in customer trucks over last 3 or 4 years. Anymore we purchase new engine and install them we seemd to have better luck that way. If you are confident in your engine building skills you can build your self a nice engine. When I build mine it balanced blueprinted, splayed mains, 20 over, ported and polished heads intake runners matched to the heads, 40 Hp injectors, gear to gear timing installed after orginal build( need truck to make west coat trip before parts came in) did everthing for under 4000.00 runs great

good luck

[soulman67]

well today I patched it with some JB weld, it still vibrates a little and it made a 4 hour trip from my parents house to mine. I am just hoping it will stay together till the end of the symester, I am a machinst student at TSTC. I plan on rebuilding the whole truck to like new. I build and restore classic cars as a hobby. I do have some radical plans for the engine but I don't know if I want to try them out on the engine for this truck.

Like custom grinding a much larger cam, grind valve reliefs in the pistons for clearance, balance it port match heads and polish the exahuast ports. Use all the hotrod tricks, and figuring out how to improve the injection pump for more fuel. Put that solid egde program to work.

[tommac95]

Soul--
>>don't know if I want to try them out on the engine for this truck
Most hotrod tricks aren't totally relevant to low revving engines.

If you do splayed mains, this would be good project. Be sure to read the 3-part discussion of RonnieJoe's rebuild.