Fwd: [DeTomaso] Engine Misfire

[John Bentley (jab)]

Rule #1:

Mechanical things never, ever, fix themselves.  Do yourself a favor and
pull the heads and find out what is going on.  Chances are the last guy
to do the valve job didn't give enough valve guide clearance......

JB

 

-----Original Message-----
From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com]
On Behalf Of hoppe1
Sent: Saturday, January 06, 2007 8:20 PM
To: Asa Jay Laughton; sean mundy
Cc: detomaso at realbig.com
Subject: Re: Fwd: [DeTomaso] Engine Misfire

Install the new push rod and run a pressure test on that cylinder.  I
think 
if the valve is bent it will not hold presssure.  If the cylinder has
good 
pressure, I would run it.
Rich
----- Original Message ----- 
From: "Asa Jay Laughton" <asajay at asajay.com>
To: "sean mundy" <seanmundy at hotmail.com>
Cc: <detomaso at realbig.com>
Sent: Saturday, January 06, 2007 8:22 PM
Subject: Re: Fwd: [DeTomaso] Engine Misfire


> Sean,
>
> Normally, I'd say put a new pushrod in, adjust the rocker properly and
go 
> on your merry way.
>
> But. . .
>
>
> I'm betting you have a bent valve.
>
> Notice the top of the valve stem on that one valve that has the bent 
> pushrod.  Now, eyeball that against the second next valve over (i.e.
skip 
> a valve).  They should be about the same if the other valve is at it 
> highest point.  I'm betting the target valve is sitting slightly
lower, 
> slightly compressing the spring.
>
> You are in for a head removal dude.
>
> When was the last time the heads were off?  If not too long ago, just
don 
> the one head.  Otherwise, if it's been a long time, you might consider

> both.
>
> What caused it?  I'd bet you have adjustable rockers and one was not 
> adjusted quite right, perhaps too tight and during a spirited romp,
the 
> engine revved high enough to have the valve kiss a piston.  Ask me how
I 
> know. :)
>
> Asa Jay
>
> sean mundy wrote:
>
>> Well, I just figured out why my engine was backfiring.  I removed the

>> spark plug wire from the #5 cylinder and started the engine.  No more

>> backfire.  I removed the left bank valve cover and oh, oh, one of the

>> pushrods is bent. I think its the intake valve (the second one of the
two 
>> from left to right)?  The rocker arms also seem very loose compared
to 
>> the others on the head.
>> So, now what?
>> What caused this to happen?  Can I simply replace the pushrod?  Do I
need 
>> to remove the head for this?  SHould I take the head off and
determine 
>> why the pushrod bent?  Rebuild both the heads even though its only
got 
>> 32k on the motor?  Thanks for any advice
>>
>>
>>
>>
>
> -- 
> Asa Jay Laughton, MSgt, USAFR, Retired
>
> & Shelley Marie
> Spokane, WA
>
> 1973 Pantera L 5533
> [ASASCAT]
>
> ******************************
> http://www.asajay.com
> http://www.351c.info
>
>
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