[DeTomaso] I need some advice from you Fordies

Mon Jan 18 13:48:34 EST 2010

One of my theories is occasional drops in oil pressure cause hydraulic
lifters to partially collapse.  Once they collapse, the clearance at the top
of the pushrod goes from zero to maybe 0.300" (lobe lift at cam).  That much
clearance is enough to allow the pushrod to drop out of the rocker cup.
When the oil pressure is restored, if the pushrod is out of the cup, it will
try to open the valve too much.  I imagine it will hit spring bind first,
before hitting a piston with a valve.  Either one will bend pushrods.

We used to have a 68 T-Bird with a 429.  It bent pushrods on a regular
basis.  It was most likely due to the teenage drivers - pushing it too hard.

I don't think inline valve engines are as susceptible.  You hardly ever hear
about 5.0 or 351W engines bending pushrods, but you hear about it with 351C
and 429/460 engines quite a bit.

My other theory is the #8 intake is the most susceptible.  The oiling goes
along the passenger's side first, with a crossover at the rear of the block,
and then to the driver's side.  The pressure will be lower on the driver's
side, since the oil is bleeding off several places along the way.  Where the
oiling passages hit a dead-end or abrupt change, the oil will back-up, and
therefore there will be higher pressure.  That's why I think #8 intake is
the most susceptible, followed by #8 exhaust, #7 intake, and so on.  They're
on the driver's side, the farthest away from the "end-of-the-line".  And
that's why I'm using the front-to-rear line.  It helps equalize the
pressure.

That's also why I like solid lifters.  You still have to worry about oiling,
but if you do have a momentary drop in pressure, you're pushrods are safe.

-----Original Message-----
From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
Behalf Of Charles McCall
Sent: Monday, January 18, 2010 12:33 PM
To: 'Dave Londry'; 'John Taphorn'
Cc: detomaso at realbig.com
Subject: Re: [DeTomaso] I need some advice from you Fordies

I had all kind of engine problems in 2001 when my engine was rebuilt. It
would bent pushrods every 500 miles, and Mr. Drew and I suffered
tremendously on a cross-Europe trip that ended with the car on a flatbed and
me in a rental car. 

The causes were many, but one of them was that the stock guideplates were
sideloading the pushrods... the mechanic cut them apart and rewelded them so
that they would do their job - "guide" but not sideload. There were other
problems that contributed to a short engine life, but I would recommend
always checking to make sure that the guideplates aren't binding the
pushrods or you could have problems...

Charles McCall
1985 DeTomaso Pantera GT5-S #9375
"Raising Pantera Awareness Across Europe"
http://www.poca.com/index.php/gallery/?g2_itemId=2323
-----Mensaje original-----
De: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] En
nombre de Dave Londry
Enviado el: lunes, 18 de enero de 2010 19:07
Para: John Taphorn
CC: detomaso at realbig.com
Asunto: Re: [DeTomaso] I need some advice from you Fordies

Well damn. I wasn't going to think of that John.
And I have a MIG that just sits around doing nothing.
So you had one that wasn't damaged, but wouldn't line up with the stock 
guideplate?

dave
(rockershafts are less exciting)

John Taphorn wrote:
> Dave
>
> If you own a MIG, the task is relatively easy.  I removed my 
> guideplate, cut it in half with a sawzall.  Then refit the two pieces 
> of the guideplate in the head and align them so as the rocker's roller 
> tip are dead center on the valve stem tip.  Shielding the rest of the 
> engine from potential weld splatter, tack the guideplate with your 
> MIG.  Then remove the guideplate and finish your weld safely away from 
> the engine.
>
> I did do mine before the engine was in the car and it certainly made 
> it more accessible.  Remember to disconnect your MSD should you be 
> using one.
>
> JT
>
> ----- Original Message ----- From: "Dave Londry" <davel at emspace.com>
> To: "Will Kooiman" <wkooiman at earthlink.net>
> Cc: <detomaso at realbig.com>
> Sent: Sunday, January 17, 2010 8:56 PM
> Subject: Re: [DeTomaso] I need some advice from you Fordies
>
>
>> Will
>> Yes there is a big difference in the centering of #8 intake & exhaust.
>> No crack in the guide plate though, they all have that stamping mark
>> through the 5 in the part number.
>> No metal has come off the roller yet and the mark is in line with the
>> edge of the valve stem,
>> so I think it will be OK after I get it lined up. Bent pushrod is a
>> good thought.
>> Anyhow I'll take it off and have a good look. And I'll align them all.
>>
>> Any warnings beyond "don't drop hard shit down the oil drains"?
>>
>> Taking off the right cover is harder than I thought.
>> It's pinned down by the support on the hard coolant line to the swirl 
>> tank.
>> Looks like I'm going to have to ask the coolant line to flex a little 
>> bit.
>>
>> Next time it'll seem normal, but it's an adventure this time.
>> Hard on the knees too.
>>
>> thanks for the advice.
>> dave
>>
>> Will Kooiman wrote:
>>> Wait a minute.  I just noticed how far #8 intake is off.  #8 exhaust 
>>> looks
>>> centered.  The guide plate also looks cracked - by the PN.
>>>
>>> Take it apart and see if anything is broken.
>>>
>>> It might be as simple as a bent pushrod.
>>>
>>> -----Original Message-----
>>> From: Will Kooiman [mailto:wkooiman at earthlink.net]
>>> Sent: Sunday, January 17, 2010 6:26 PM
>>> To: 'detomaso at realbig.com'
>>> Subject: RE: [DeTomaso] I need some advice from you Fordies
>>>
>>> It could be as simple as the guide plates being too far to one side.  I
>>> spent a lot of time aligning my rockers.  I didn't have to 
>>> cut/reweld them.
>>>
>>> Before you tighten the rocker stud, you can slide the guide plate 
>>> left and
>>> right (and up/down).  If you slide it to the left, the rocker tips 
>>> slide to
>>> the right - and vice versa.  You keep fudging with it until they're 
>>> in the
>>> center for both intake and exhaust.
>>>
>>> I don't know about the galling.  I'd guess it's due to oiling (lack
>>> thereof).  One of the reasons I went with Crane Gold Race rockers is 
>>> because
>>> of comments I heard about how it handled oiling.  On one engine, I 
>>> cut the
>>> tops off of an old set of valve covers, and ran the engine.  If you 
>>> try it
>>> without valve covers, you'll shoot oil like a little oil well.
>>>
>>> I also spent a lot of time making sure nothing was rubbing or 
>>> binding. Most
>>> of my intake pushrods were rubbing the guide plate (in the wrong 
>>> place -
>>> they always rub on the edges).
>>>
>>> If it were me, I'd remove the rocker and inspect it more closely.  
>>> If it's
>>> discolored, it probably overheated.  I'd think a little blueing is 
>>> okay, but
>>> I'm not an expert.  If it has galling, I'd replace it for sure.  A new
>>> rocker is cheaper than a new valve.
>>>
>>> I'd also check the alignment of the rockers - especially #8.  The 
>>> rollers
>>> should be centered on the valve stem.
>>>
>>> -----Original Message-----
>>> From: detomaso-bounces at realbig.com 
>>> [mailto:detomaso-bounces at realbig.com] On
>>> Behalf Of Larry Finch
>>> Sent: Sunday, January 17, 2010 5:29 PM
>>> To: detomaso at realbig.com
>>> Subject: [DeTomaso] I need some advice from you Fordies
>>>
>>> Is this the situation where sometimes the roller guides need to be
>>> cut, sectioned and welded?
>>>
>>> I'm book learned, but have no first hand knowledge... ;-)
>>>
>>> Larry
>>> _______________________________________________
>>>
>>> Detomaso Forum Managed by POCA
>>>
>>> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>>>
>>> DeTomaso mailing list
>>> DeTomaso at list.realbig.com
>>> http://list.realbig.com/mailman/listinfo/detomaso
>>>
>>> _______________________________________________
>>>
>>> Detomaso Forum Managed by POCA
>>>
>>> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>>>
>>> DeTomaso mailing list
>>> DeTomaso at list.realbig.com
>>> http://list.realbig.com/mailman/listinfo/detomaso
>>>
>>>
>>>
>> _______________________________________________
>>
>> Detomaso Forum Managed by POCA
>>
>> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>>
>> DeTomaso mailing list
>> DeTomaso at list.realbig.com
>> http://list.realbig.com/mailman/listinfo/detomaso 
>
>
>
_______________________________________________

Detomaso Forum Managed by POCA

Archive Search Engine Now Available at http://www.realbig.com/detomaso/

DeTomaso mailing list
DeTomaso at list.realbig.com
http://list.realbig.com/mailman/listinfo/detomaso

_______________________________________________

Detomaso Forum Managed by POCA

Archive Search Engine Now Available at http://www.realbig.com/detomaso/

DeTomaso mailing list
DeTomaso at list.realbig.com
http://list.realbig.com/mailman/listinfo/detomaso