-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Terrible Tom
Sent: Wednesday, January 31, 2007 9:35 PM
To: dakota-truck-moderator@bent.twistedbits.net
Subject: Re: DML: cyl 1 and 7 don't fire
Jamie Calder wrote:
> A while ago I posted a problem I had with my '93 318 where cyl 1 and
> 7 don't fire. A compression test shows there no compression at all in
> those 2 cylinders. Before I take the valve cover off for further
> inspections, would anyone like to speculate? Why those 2 cylinders at
> the same? Are those 2 always in the same position? What would cause 2 to
go at once?
> What would be the best case scenario? Rockers or pushrods, right?
>
> Thanks,
> James
>
>
1-8-4-3-6-5-7-2 - is the firing order. The number 1 and number 7 are the
front and rear two on the drivers side bank... Why the two are not getting
compression, is a little odd.
You either have a situation where the timing is off, and the piston is
hitting TDC while you have a valve open, you have burnt/broken valves, or
you have damaged pistons.
Odds are - if the timing has not been fussed with, and the chain in intact,
you have bad valves. I could see if you had no compression between two
common cyls, (indicating a hole on the block or head)... but two opposites?
Its not impossible to have fubard pistons... but it would take some serious
destructive force to take out two of em.
Why do I not suggest rings? Because even with bad rings, you should still
have SOME compression, be it very low. If you have ZERO compression, I'm
suspecting valves.
-- ------------------------------------------------------------ Get a freaking rose tattoo and deal with it... ------------------------------------------------------------ three busted-ass daks, a gas hog, and a rollerskate http://members.aol.com/silvereightynine/ AIM & Yahoo: SilverEightynine ------------------------------------------------------------The chain is intact, it still runs on 6 cyls. It's a double roller with the tensioner installed with only 30,000 miles on it so I doubt it skipped. It would seem the timing is good and not the issue. The pistons and rings have the same low miles on them also. KRC ported and rebuilt the heads, new springs, brass guides etc. Still has the original valves and stamped rockers though. Defiantly not saying new stuff doesn't break though...
I'm sure I'll know a lot more when I take the cover off.
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