larry-larry-larry(in that order..lol)
it is not an issue in a pure stock aplication with all stock tolerances.
cam journals that is. now with motors with no cam bearings a few things
happen.
1 the bores do wear , resulting in a place where the oil pressure is not
properly retained evenly around the cam.
2 the uneaven wear in the bearing bore results in a hot spot on the bottom
side of the bore due to a tight tolerange on bottom side
3 the 2 above reasons will result in oil pressure "bleeding off" around the
cam bearings and causing oil pressure to be lower that it could be
potentially be.
4 a higher lift cam will need to be properly suported in it's bearing bores
or any inconsistency in suport can lead to a camshaft catasrophic failure.
oil pressure is the life blood of an engine. the name of the game is
proper lubrication with proper distribution. if a weak link is left
ignored it can lead to premature or catsstrophic failure.
an interesting side bar to this is this. many shade tree mechanics do
engine rebuilds at home. since cam bearings are not very easy to replace
without a proper tool , without damaging them ,they tend to be left ignored.
but! the oversight is usually the first step to bottom end failure due to
poor oil pressure from first start up. many owners install a high volume
oil pump or a high pressure relief valve spring. in an engine with new
internals and worn cam bearings it is a false indicator when the gauge reads
"incredibly good pressure". in the 1500's case you might not too bad off
but if you are doing it once and going to do it right , the added expense is
not a bad investment in your cars future. it is not just something neat to
do that will go unseen in the car's future.
chuck.
----- Original Message -----
From Larry Macy <macy at bblmail.psycha.upenn.edu>
To: <mgraziano@mindspring.com>; <Daniel1312@aol.com>
Cc: Spridgets <spridgets@autox.team.net>
Sent: Sunday, October 08, 2000 2:40 PM
Subject: Re: Re: Camshafts
> >>>>On 10/6/00 1:06 PM so and so (Daniel1312) said. (And I quote:)
>
> >
> >Get in contact with APT and see what they say.
> Well I looked on their web site (www.aptfast.com) and what a cluster f**k
> that is. I spent well over an hour and could not find anything, unless I
> had the part number. And I could find no way to find out what the part
> number was. Last update was on my last birthday - December of 1999 (send
> those cards and letters now folks, don't forget the checks)
>
> So I called, lady answering the phone was very nice, but unknowing in the
> parts area. The folks I need to talk to will be in on Tuesday. So I will
> call back.
>
> On a side note.
> >>>>On 10/6/00 1:06 PM so and so (mgraziano@mindspring.com) said. (And I
> quote:)
> >If I had the cash, I would have had the cam and block ground for cam
> bearings.
>
> Why is there such an issue with the cam bearings?? anyone ever have one
> fail? The journals are like 1 inch, or less, from the oil galley. I have
> yet to see one go bad, or hear of anyone that did. I was asked yesterday
> if I was gonna have the galley enlarged, I think not. Besides all the
> pressure issues that will engender. I have 90,000 miles on the engine in
> the car and it didn't break at the cam journals, or at least I hope that
> is not what is wrong. I suspect not. Why fix something that ain't broke.
>
> Seems to me that the KISS principle applies here. Why add another piece
> to the puzzle. Yea I know that this is one of the few engines that has no
> cam bearings, but so?? It works. The cam is not subjected to the side -
> to - side forces that a crank is. It just, basically, goes round and
> round. As long as there is oil there, which there would be unless the
> pump failed, what is wrong with no, soft WEARABLE material, cam bearings?
>
> Somebody give me definate failures on the cam bearing issue and I might
> rethink my decision to forego this "modification".
>
> Remember, I worked on industrial engines and any failure was always at
> the crank, never the cam.
>
> Just wondering out loud.
>
> Larry
>
> Larry Macy
> 78 Midget
>
> Keep your top down and your chin up.
>
> Larry B. Macy, Ph.D.
> macy@bblmail.psycha.upenn.edu
> System Manager/Administrator
> Neuropsychiatry Section
> Department of Psychiatry
> University of Pennsylvania
> 3400 Spruce St. - 10 Gates
> Philadelphia, PA 19104
>
> Ask a question and you're a fool for three minutes; do not ask a
> question and you're a fool for the rest of your life.
>
>
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