[DeTomaso] Update - cause of death - blown engine

[Asa Jay Laughton]

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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