[DeTomaso] BBORR engine failure clues

Will Kooiman wkooiman at earthlink.net
Thu Apr 30 12:35:32 EDT 2009


The only broken cams I've heard of were due to something else breaking
first.

Wait a minute.  I seem to remember one of the magazines, Hot Rod, Car Craft,
??, breaking a camshaft.

I don't think you're running enough spring pressure to break it.  I don't
think you can run enough spring pressure with a flat-tappet to break a cam.

It could be a cracked camshaft core that just finally broke - but I doubt
it.

The cam retainer plate might have come loose, which could have allowed the
cam to walk forward enough for the back journal to come out of the bearing -
and then it would have broken.  But I seriously doubt that's possible.  All
the lifters and the distributor would have prevented it from walking forward
that far.

It could be bad ju-ju.  My cam broke on that road last year.

It could be a broken rod.

If you cracked a piston on #4 or #8, the pieces could have lodged into the
camshaft.  It would have snapped the camshaft pronto.  If the lifters drop
far enough, it will expose the oil passages and you'll see low oil pressure,
and probably melted bearings on #4 and #8.  That's how my camshaft broke.
That's also my final answer.

-----Original Message-----
From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
Behalf Of michael frazier
Sent: Thursday, April 30, 2009 10:44 AM
To: asajay at asajay.com; pantera list
Subject: Re: [DeTomaso] BBORR engine failure clues


Ok, now back to my problem.  This engine does NOT have roller lifters.
Everytime I open a post hoping someone has
great info about my failure or is willing to give me a new engine or parts I
see...JUST KIDDING, JUST KIDDING!


I'm pretty sure it looks like a broken cam with 2 cylinder's lifters down
and oil in the bell housing area.  I don't have any 

experience with this.  Are there any common causes for this.  I assume it's
a result of torsional loads, but?  What kind of

collateral damage is likely?  I can imagine some block damage, bent valves
etc.  Thanks for any info...and that was good info on roller lifters too.
:)

Michael
 
> Date: Thu, 30 Apr 2009 07:58:53 -0700
> From: asajay at asajay.com
> To: detomaso at realbig.com
> Subject: Re: [DeTomaso] BBORR engine failure clues
> 
> Very good point Gray, thank you for clarifying.
> 
> Asa Jay
> 
> Quoting Gray Gregory <rgg at gregorycook.com>:
> 
> > Asa,
> >
> > You can add me to that list too. I agree with John that solid roller 
> > lifters are a problem waiting to happen and are not worth the extra 
> > hp for a street driven car, of course that's just my opinion!
> >
> > It's important that we separate solid roller lifters and hydraulic! 
> > The modern engines you talk about all have hydro roller lifters and 
> > the shock absorption effect the hydro lifters give you eliminates 
> > the problem of the needle bearings failing from the shock as the 
> > lash is taken up.
> >
> > Gray
> >
> > -----Original Message-----
> > From: detomaso-bounces at realbig.com 
> > [mailto:detomaso-bounces at realbig.com] On Behalf Of Asa Jay Laughton
> > Sent: Wednesday, April 29, 2009 11:43 PM
> > To: detomaso at realbig.com
> > Subject: Re: [DeTomaso] BBORR engine failure clues
> >
> > I don't see them as a "frequent" source of engine failure. I've seen
> > more engine failures talked about due to broken valves, overbores that
> > "windowed" a cylinder wall, broken cams, worn mechanical lifters,
> > sheared distributor pins, and the list goes on. I've only heard of one
> > failure due to a roller lifter going out, and that was today from John
> > Taphorn. So I'm not really seeing any data that roller lifters are a
> > frequent source of failure.
> >
> > For what it's worth.... most modern engines only use roller lifters now,
> > which is why most cam grinders now have lower profile grinds for use
> > with roller lifters. It used to be if you wanted to use roller lifters,
> > your cam selection was very limited, usually to strip and track only
> > grinds. Nowdays you can get a good street grind for everyday driving.
> >
> > Is it worth it? Heck yea... reduced friction, reduced load, both of
> > which lead to better gains in HP. Modern components last a lot longer,
> > etc. What's not to like about them?
> >
> > 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
> >
> >
> >
> >
> > pantdino at aol.com wrote:
> >> To admit my ignorance:
> >> Seems like these roller cam followers are a frequent source of engine
> >> failure.
> >> Is it really worth it? Do you really gain that many HP?
> >>
> >> Jim
> >>
> >>
> >>
> >> -----Original Message-----
> >> From: John Taphorn <jtaphorn at kingwoodcable.com>
> >> To: michael frazier <red3644 at hotmail.com>; pantera list
> >> <detomaso at realbig.com>
> >> Sent: Wed, 29 Apr 2009 8:16 pm
> >> Subject: Re: [DeTomaso] BBORR engine failure clues
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> Michael
> >>
> >> I believe that you stated you were running a solid roller lifter cam.
> >> The
> >> excess lash occurs as the needle bearings in the roller's wheels turn
> >> to
> >> dust. The base of the roller then rides on the cam lobe and the wear
> >> rapidly against one another.
> >>
> >> Welcome to solid roller hell from one who has made the journey.
> >>
> >> JT
> >> ----- Original Message -----
> >> From: "michael frazier" <red3644 at hotmail.com>
> >> To: "pantera list" <detomaso at realbig.com>
> >> Sent: Wednesday, April 29, 2009 9:36 PM
> >> Subject: [DeTomaso] BBORR engine failure clues
> >>
> >>
> >>
> >>> I had a chance to pull the distributor, intake and valve covers
> >>>
> >> tonight.
> >>
> >>> The dist. gear is pinned tight where it should be. The rockers
> >>>
> >>> (intake and exhaust) for the back two cylinders, 4 & 8, are loose and
> >>> almost off the springs. Lifters are down. That's as far as I've
> >>> got...any new thoughts? I'll keep you posted.
> >>>
> >>> Michael
> >>>
> >>> _________________________________________________________________
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