[Fot] Distributor gear failure

[Bill Babcock]

I've heard anything more than 10 pounds per thousand RPM is a waste of power.
On Mar 28, 2011, at 4:50 PM, Greg & Alison Blake wrote:

> Interesting thought about too much oil pressure.  Whats too much?
>
> -----Original Message-----
> From: fot-bounces at autox.team.net [mailto:fot-bounces at autox.team.net] On
> Behalf Of MadMarx
> Sent: Monday, March 28, 2011 11:50 AM
> To: fot at autox.team.net
> Subject: Re: [Fot] Distributor gear failure
>
> Maybe it is a combination of things.
> - Too much oil pressure which rises the gear load
> - high lift cams which don't continuously spin, they have a pulsing
rotation
> caused by valve and springs
> - high revs which can cause resonances on the front part of the cam where
> the gear sits
>
> This could result in some kind of pitting that starts to end the story.
>
> But very difficult to tell.
>
> Chris
>
> -----Urspr|ngliche Nachricht-----
> Von: Tony Drews [mailto:tony at tonydrews.com]
> Gesendet: Montag, 28. Mdrz 2011 18:45
> An: MadMarx; fot at autox.team.net
> Betreff: Re: [Fot] Distributor gear failure
>
> Interesting theory.  Jack did not have too much oil pressure when the
> gear failed.
>
> - Tony
>
> At 11:37 AM 3/28/2011, MadMarx wrote:
>> Could it be an oil pressure issue?
>> When I installed the cam I also installed a new crank with a smaller
> bearing
>> clearance.
>> The oil pressure was pretty good after that.
>> Cold close 100 psi, hot around 85-90 psi.
>> I didn't change the relive valve and ran that engine several races with
> this
>> high oil pressure.
>> Maybe the gear failed from too much stress caused by the oil pump?
>>
>> Had Jack too much oil pressure?
>>
>> Chris
>>
>>
>> -----Urspr|ngliche Nachricht-----
>> Von: fot-bounces at autox.team.net [mailto:fot-bounces at autox.team.net] Im
>> Auftrag von Larry Young
>> Gesendet: Montag, 28. Mdrz 2011 18:19
>> An: fot at autox.team.net
>> Betreff: Re: [Fot] Distributor gear failure
>>
>> I have been watching this discussion with interest, because I would like
>> to know if there is some gear alignment method I don't know about.
>>
>> I'm familiar with the failure that Jack had and do not believe it was
>> due to a problem with the blank.  Back in 2005, I purchased two blanks
>> from the UK and had them ground.  One went into my car and one into
>> Jack's  Mine never failed.  Jack's failed immediately after he had
>> another problem with a valve hitting the top of the cylinder liner.  I
>> believe the force of  the impact was transmitted through the pushrods to
>> the cam causing deflection and misalignment of the gears.  This occurred
>> at the 2006 gathering at Hallett.
>>
>> More recently I have gotten more than 20 blanks from Racestorations in
>> the UK.  Chris has had the only problem with a gear.  The vendors, Moss,
>> BPNW, etc., must sell large numbers of cams ground on new blanks, yet we
>> don't hear of may gear failures.
>>
>> - Larry Young
>>
>> On 3/27/2011 4:07 PM, Kramer, Robert wrote:
>>> Uncle Jack came to the conclusion that the aftermarket blanks had
>> incorrectly hobbed gears for the distributor drive. I've stayed with
>> regrounds ever since.
>>>
>>> Bob Kramer
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Bill Babcock
billb at bnj.com
503.936.7660
www.bnj.com