carbon build up

[29Coupe348]

i am in the process of changing my cam, lifters, springs, and valves...i took ti all apart today, and i noticed excessive carbon build up on the pistons, valves, and plugs...what may be causing this?, and how can i prevent it?...its a basically stock motor with a comp 268h cam and 3x2's, and a pertronix in the distributor.

[johnnyrod]

Maybe a bit more long highways runs to help keep it cleanes out. A lot of short euns tends to build carbon. I hope this can help. John

[29Coupe348]

well, if it wasnt excessive, i would think the same...do you think maybe not enough spark?

[johnnyrod]

I allso have 348 tri power with a 340 hp cam 288/300 duration. I have the petronix and I thouht that the spark was a bit weak so am going to the peronix 2 system. Do you run it out on some long cruises. John

[fatride]

Could be oil from worn valve guides not carbon!

[29Coupe348]

new valve seals, and guides were put in last year...the only reason i took it back apart this year is because i think that the springs i used were too heavy, so im going with a single spring. so i figured since its apart, i'll change the valves, and seals.

[raymar58454]

It could also be carbon from oil getting past the rings. Could be a canidate for the 20 mule team which we got into a discussion under GM engine knock post in the general discussion forum. Check it out .

Ray