[Fot] Accusump & bearing coatings

[Tim Murphy]

Ibve been told that the coating is so thin that the journal size does not
have to be changed to accommodate it.  I think it may even say that on
Calicobs web site.  I wouldnbt think 0.00025 to 0.00030 inches added to
the bearing thickness would make too much difference, granted thatbs a half
a thousandth on the diameter.  I have found that measuring the bearing bore,
the bearing shell thickness and the crank journal can add up to probably an
error of +/- 0.0002 to 0.0003 just in the stack up of the estimated measuring
error.  That is unless you have access to some really good calibrated
metrology equipment.  Measuring to 1/10,000 of an inch is pretty darn hard,
even with good equipment.



Tim



From: toodamnfunky at comcast.net [mailto:toodamnfunky at comcast.net]
Sent: Wednesday, September 15, 2010 12:19 PM
To: Tim Murphy
Cc: Randall; fot at autox.team.net; Bill Babcock
Subject: Re: [Fot] Accusump & bearing coatings



I read on Tony's site that he uses Calico for bearing coatings applied at .25
- .30 mil.

( per Calico )

In my upcoming build I plan to cryo treat and nitride the crank and coat the
bearings.



Does anyone know if an allowance needs to be made for the bearing coating when

cutting a crank? and should the rod bearings be coated as well and again with
the

allowance for the coating on the rod bearings.



Jim G




----- Original Message -----
From: "Tim Murphy" <timmurph at fastbytes.com>
To: "Bill Babcock" <billb at bnj.com>
Cc: "Randall" <TR3driver at ca.rr.com>, fot at autox.team.net
Sent: Wednesday, September 15, 2010 10:53:23 AM
Subject: Re: [Fot] Accusump

One other thing, we're using the coated bearings which I know some other
folks are using on the TRactor motors.  I would think that would also help
prolong the life with a "cold" start.  I don't know which coating the
machine shop sent them out for.  I think it was to the guy here in Wisconsin
who I had heard more or less invented the bearing coating when he was
working at Mirro Aluminum and doing work on coated pots and pans.

Tim

-----Original Message-----
From: Bill Babcock [mailto:billb at bnj.com]
Sent: Wednesday, September 15, 2010 10:54 AM
To: Tim Murphy
Cc: 'Randall'; fot at autox.team.net
Subject: Re: [Fot] Accusump

Probably only worthwhile if you pull the plugs first, otherwise you're
probably shortening the life of an already overworked starter. Of course if
you do that make sure you disconnect the power lead to the coil, or you're
sending sparks everywhere and shortening the life of an overworked coil,
distributor, and plug wires. Then reconnect everything quickly and fire it
up. Or flip on the ignition switch with an accusump connected and wait for
your oil pressure to peak at 20 pounds and start it while the system is
fully pressurized.

Hmm, I wonder which is better.

On Sep 15, 2010, at 8:17 AM, Tim Murphy wrote:

> Is there any advantage to cranking the engine without ignition until the
oil
> pressure comes up and then flipping the ignition on to fire it?  If would
> seem the loads on the bearings with just cranking it over would be quite a
> bit less, and less damaging, than actually firing the engine immediately.
>
> Tim
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