[DeTomaso] BBORR engine failure clues

Gray Gregory rgg at gregorycook.com
Thu Apr 30 10:17:24 EDT 2009


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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