[DeTomaso] Update - cause of death - blown engine

Will Kooiman wkooiman at earthlink.net
Mon Jan 11 00:08:36 EST 2010 

Good idea on the tape.

I have my procedure too - do's, don'ts, and so on.  Too boring to list - and
besides, like I said, I'm not a professional, so it isn't worth repeating.

My comment on the new torque wrench was to get one that was easier to dial
to the proper torque.  I probably thought it was on 67, but it was actually
on 42.  It's 15 lb/ft per rotation.

I will say this, though.  Up until it blew, it was making a lot more power
than it ever has before.  I'm really close on the ideal 351C (for me).  If
Tod B. can get his alum blocks ready, I'll be in Pantera Nirvana.

-----Original Message-----
From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
Behalf Of Asa Jay Laughton
Sent: Sunday, January 10, 2010 10:48 PM
To: 'De Tomaso List'
Subject: Re: [DeTomaso] Update - cause of death - blown engine

The brand of torque wrench isn't necessarily the key.  The key is making 
sure it's calibrated.  I'm sure your local Snap-On dealer can help you 
with that though.

I've only done a handful of engines myself.  My first ones were during 
the time I spend earning my Automotive Technologies degree.  I don't 
remember what sparked it, probably something that had happened to other 
classmates, I can't be sure.  On every engine I've built, I never button 
it up the same day I torque it.  I go through all the proper torque 
procedures, then walk away.  The next day I come back and check the 
torque on all the bolts.  After a couple days of that as I perform other 
stuff, I put the pan on.

That's still no guarantee something won't break.  However in my own 
mind, it allows me opportunity to make sure it's right -and- make sure 
nobody else messed with it.

The other thing I do is duct tape all the ports, exhaust ports, intake 
ports, manifold etc.  One of the first engines in our class promptly 
bent a valve and punched a nice hexagon shaped hole in the top of a 
piston.  Somehow, the partners on that one had managed to drop a nut 
down the cylinder.  So my partner and I did a quick inspection, then 
taped all the ports shut.

:)
Asa Jay

Asa Jay Laughton, MSgt, USAFR, Retired

& Shelley Marie
Spokane, WA

1971 Mach I Mustang  [ASA JAY]
1973 Pantera L 5533  [ASASCAT]
    
******************************     
http://www.asajay.com
http://www.teampanteraracing.com
  



Will Kooiman wrote:
> The bummer is I know I torqued the rods.  I even used a rod stretch gauge
to
> measure the stretch - just for grins.  I can't explain, however, why it
only
> took 40-50 lb/ft to loosen the bolts.
>
> Also - I'm definitely not a professional, but I've put together several
> engines - maybe 10 or 15.  This is the first time anything like this has
> happened.
>
> I'm going to put the next one together too, but this time I'm going to
make
> damn sure the torque is correct on all of the critical bolts.
>
> I'm also going to buy a better torque wrench - probably snap-on.
>
> -----Original Message-----
> From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com]
On
> Behalf Of Asa Jay Laughton
> Sent: Sunday, January 10, 2010 9:23 PM
> To: 'De Tomaso List'
> Subject: Re: [DeTomaso] Update - cause of death - blown engine
>
> wow
>
>
>
>
> Asa Jay
>
> Asa Jay Laughton, MSgt, USAFR, Retired
>
> & Shelley Marie
> Spokane, WA
>
> 1971 Mach I Mustang  [ASA JAY]
> 1973 Pantera L 5533  [ASASCAT]
>     
> ******************************     
> http://www.asajay.com
> http://www.teampanteraracing.com
>   
>
>
>
> Will Kooiman wrote:
>   
>> I pulled my engine today.  I haven't taken it completely apart, but I
>>     
> pulled
>   
>> the pan.
>>
>>  
>>
>> The official cause of death is:      The #4 rod cap came off.  It appears
>> that the rod bolts were not properly torqued.
>>
>>  
>>
>> Here's what I found inside the pan:
>>
>>  
>>
>> The #4 rod cap was not attached to the crank.  A rod bolt was in the pan.
>> I'm sure the other rod bolt is in the pan somewhere, but I haven't found
>>     
> it
>   
>> (haven't looked through the sludge).
>>
>>  
>>
>> The #4 rod cap was in one piece in the pan.  It was flattened out.
>>
>>  
>>
>> I found the #4 rod bearing.  It is still in a half circle.  I haven't
>> examined it very much.  It was getting dark, and I had to do chores.
>>
>>  
>>
>> The #8 rod is broken in half.  The cap is still on the crank.  I
>>     
> previously
>   
>> thought it was the #4 rod that was broken.  I couldn't tell for sure
>>     
> because
>   
>> I was looking down the #4 bore -- which had the #4 piston lodged sideways
>>     
> in
>   
>> it.
>>
>>  
>>
>> The #8 piston has the pin broken out of the piston.  At first I thought
>>     
> the
>   
>> piston came apart to cause the destruction, but it looks like the crank
>> counterweights cut it off after the rod broke and the piston dropped into
>> the crank.  The counterweights have some debris on the leading edge to
>> support this theory.
>>
>>  
>>
>> The #4 main cap (between #3/7 and #4/8) is cracked at the base.
>>
>>  
>>
>> The #4 cylinder is cracked.  I think this happened when the #4 piston
went
>> sideways.  I don't know about #8.  I haven't removed the driver's
cylinder
>> head.
>>
>>  
>>
>> The #4 rod journal is gouged slightly on one side.  It looks like it got
>>     
> hit
>   
>> after the rod came off.  If the bearing had spun, it would have cut
>>     
> grooves
>   
>> along the entire circumference.  I think the crank is going to be
>>     
> reusable.
>   
>>  
>>
>> I just bought a new torque wrench -- in case my old wrench was
inaccurate.
>>     
> I
>   
>> checked the #8 rod.  It was only torqued to 40 lb/ft.  It is supposed to
>>     
> be
>   
>> torqued to 67.  I checked a few of the other rods, and they were in the
>> 40-50 range too.
>>
>>  
>>
>> I checked a couple of the inner mains (ARP studs).  They were around 120
>> lb/ft.
>>
>>  
>>
>> I don't think the torque wrench is bad, otherwise the mains would be off
>> too.  The inner head bolts were correct too.  The outer head bolts have
>> always lost torque due to the excessive heat compressing the aluminum.
>>
>>  
>>
>> I'm guessing that either
>>
>>  
>>
>> a)       I set the torque wrench incorrectly when I did the rods or
>>
>> b)       I didn't use the proper procedure to torque the rods or
>>
>> c)       Both.
>>
>>  
>>
>> I did not torque it, loosen it, torque it, loosen it, torque it.  I used
>>     
> the
>   
>> grey moly grease that came with the rods on the threads and under the
bolt
>> heads.  I snugged them up with a ratchet, and then I torqued them to
about
>> 35 (don't remember -- I usually go about ½ of the final torque), and then
>>     
> I
>   
>> torqued them to 67.  I measured the bolt length before and after they
were
>> torqued.  I didn't write it down, but I'm pretty sure they stretched
>>     
> 0.004".
>   
>>  
>>
>> The block is probably reusable with a sleeve, a new #4 main, and a line
>> bore.  It will probably cost more than it's worth, though. The crank
might
>> be reusable.  The #4 and #8 pistons are obviously trash as are the #4 and
>>     
> #8
>   
>> rods.  Everything else looks like it's in good shape.
>>
>>  
>>
>> I'll do pictures eventually.  It's going to be at least 2 weeks, though.
>>     
> I
>   
>> have a lot of non-car-stuff going on -- going out of town next weekend.
>>
>>  
>>
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