Date: Tue, 4 Mar 1997 08:09:11 -0800
From: Mike West <mwest@CDSNET.NET>
Subject: Re: Mike West - Straightness of rod..

>Hi Mike
>
>Im after a little advice from you but thought that it may benefit other
>members of the list as well.
>I have a shaft that I have to determine whether it  is straight or not. I
>have a DTI and stand and thats it...whats the cheapest way of finding out
>whether this thing is straight or not? I have heard that rollling it on a
>sheet of glass would help but what should I be looking for?
>
>Your advice is welcome and much appreciated.

 - - - - - - - - - - - - -

 Nick, you neglected to tell me what shaft or rod so now I have to
do all of them and hope you aren't talking about a shotgun.

 The lowly Pushrod is first:  Runout is .3mm (.012")
If you're using heavy valve springs, cut that number in half.

 This one is easy enough to see on a piece of flat glass or even a kitchen
table. 12 thousandths is easy to see with the eye when you
roll it.

 The cam shaft is next and now you need the dial indicator with stand
 a pair of "V-blocks" and a surface plate about 12" square.

 Setting the v-blocks on #1 and #3 bearing surfaces, you measure the runout
on the bearing in between.

 Should not exceed .02mm (.0008").

 On to the crankshaft:  set it up on the same bearings and measure out
there in the middle on the #2 .

 A new crank should have 00.00 runout, per Bentley.

 A wear limit is set for this and should be not more than .03mm (.0012").

 Equipment as indicated above should run you $200 for plate and v-blocks.
Not practical for one unit.

 Any decent machine shop should do this for you for the cost of a
few minutes labor. Say 15 minutes.

 Bob Hoover is pretty sure this bent crank thing is the major cause
of low miles on rebuilt engines. More so than Align-boring.

 I would have to agree, particularly if it isn't even checked.

 Anyway, run it down to a competent shop and have them check it.
It really is cheap insurance.

 west

Re: Mike West - Straightness of rod..