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-   -   4.3 Has Me WHIPPED! (http://www.hotrodders.com/forum/4-3-has-me-whipped-75024.html)

stjohn 11-29-2005 04:56 PM

4.3 Has Me WHIPPED!
 
Bought a truck the other day from a man who said it wouldn't start.Ran a compression check,no compression on #3,the other 5 were at 195.Pulled the valve cover and all 3 intake rocker studs were pulled out of the head.Drifted these back into place and adjusted the valves.It started but ran real rough,wouldn't idle.Ran another compression check,read same as the first one.I suspected a holed piston or bent valves.Pulled the head,no bent valves and a good piston that goes up and down.I sure could use some help here.Dale

poncho62 11-29-2005 05:09 PM

Did you put the plug wires back on in the right place?

How was the rocker arm movement when you put the rocker arms back on?

stjohn 11-29-2005 05:27 PM

All the rockers moved but I didn't measure the lift.Dale

machine shop tom 11-29-2005 05:31 PM

SOMETHING caused those studs to pull out. My guess is the timing chain jumped and caused the valves to hit the pistons and that interference caused the studs to pull. Another thought is the valves were adjusted too tight by somebody and the valve springs bound up and pulled the studs. I would check the pushrods and see if any are bent.

tom

ChevelleSS_LS6 11-29-2005 05:31 PM

do the valves on the dead cylinder fully close or are they stuck?

stjohn 11-29-2005 05:51 PM

It didn't appear that any valves contacted pistons.The passenger side valve train looked alright,pushrods looked o k,although I didn't roll them on a flat surface.I'll check everything closer tomorrow and take the head to the machine shop to be checked and pinned.Thanks for the replies,I have a feeling I'm missing something simple.Dale

advanced design 11-29-2005 06:14 PM

I've ran across a few 4.3's with a rough idle that turned out to be a sticky valve, ran . The compression and leak down were OK but the problem showed up on a running compression test.

stjohn 11-29-2005 06:31 PM

One thing I did notice was with the pushrods removed I tryed to push in on the lifters with a screwdriver.Only 2 collapsed about 1/4 inch.the other 4 were tight like a solid.

stjohn 11-29-2005 06:43 PM

Why would just the intake studs be pulled.And just that bank?1 and 5 were partially pulled and #3 was all the way out laying on top of the head.

schnitz 11-29-2005 07:34 PM

Quote:

Originally Posted by machine shop tom
SOMETHING caused those studs to pull out. My guess is the timing chain jumped and caused the valves to hit the pistons and that interference caused the studs to pull. Another thought is the valves were adjusted too tight by somebody and the valve springs bound up and pulled the studs. I would check the pushrods and see if any are bent.

tom

I would agree and I'd be willing to bet that the springs aren't exactly stock tension either.

Quote:

One thing I did notice was with the pushrods removed I tryed to push in on the lifters with a screwdriver.Only 2 collapsed about 1/4 inch.the other 4 were tight like a solid.

Sounds right on if the valves were adjusted too tight. And judging by the last post (if I remember the right way to set a 4.3), that would do it. But I may be wrong.



In a while, Chet.


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