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JP timing set alignment
https://www.slantsix.org/forum/viewtopic.php?t=51128		 Page 2 of 3
Author:  Dart270 [ Sun Feb 17, 2013 10:04 pm ]
Post subject: 
I assume the crank gear is seated fully onto the machined crank surface (plane perpendicular to the crank axis).

This just happened to me too, and I posted about it here. It was not the timing set but the crank and block match up. I tried 4 different kinds of timing sets (incl stock) and they all did the same thing.

I threw the crank gear on my lathe at work and chopped 0.055" off the back surface and now it is perfect.

Rick, if you want to bring it to PF, I could do it for you and mail back, or we could even do it on Sunday on your way home! Took about 10-15 min to do it. You will have to make a good measurement of the offset so we know how much to cut.

Lou
Author:  Rick Covalt [ Mon Feb 18, 2013 3:39 am ]
Post subject: 
Quote:
I assume the crank gear is seated fully onto the machined crank surface (plane perpendicular to the crank axis).
Yes it is seated well.

I will drop you a PM

Thanks
Author:  Exner Geek [ Mon Feb 18, 2013 7:00 pm ]
Post subject: 
Be careful with this. I seem to remeber that somebody, probably Barry Harrison did some machining to supposedly improve the allignment of a JP set and wound up having the chain break. The crank gear should snug up against the step on the crank but if that won't do it I would do more checking before doing any additonal machining. Try measuring the distance from the mounting surface to the teeth on the JP gears and compare it with some other double roller sets.
Author:  Dart270 [ Mon Feb 18, 2013 10:18 pm ]
Post subject: 
Thanks for the insight, Seymour. Hope to see you in a week for some Slanted hangout time!!

Lou
Author:  Rick Covalt [ Tue Feb 19, 2013 4:48 pm ]
Post subject: 
Quote:
Try measuring the distance from the mounting surface to the teeth on the JP gears and compare it with some other double roller sets.
Well, I used my last spare double roller gear set on Denny's truck so I don't have any to compare it to. But I do have a bone stock silent gear set, which I just installed and the same mis-alignment is there on them also. So I don't know that it is a problem with the JP timing set. I did measure the depth of the recess in the cam gear to the face that rides against the block and it is exactly the same at on both sets @ .185. So that depth puts the cam in the same location with both sets. As I look at it it seems to me that the cam location should be set by the cam gears face. And since both sets I have are the same they would appear to be right.
Also the crank can't move because it has a thrust bearing. So that leaves the shoulder that is machined on the crank that the lower gear sets against. Since I am not removing the crank I will just have Lou trim the back of the gear down to get the proper alignment. The actual measured mis-alignment is @ .095"

I am not sure how getting the gears lined up could cause a chain failure but I am certainly willing to listen and be taught. If anyone else has any thoughts on this please let me know.

Rick
Author:  Fopar [ Tue Feb 19, 2013 5:40 pm ]
Post subject: 
Measure the back of the new crank gear to back of that sprocket, compare to stock.

Richard
Author:  Rick Covalt [ Tue Feb 19, 2013 6:23 pm ]
Post subject: 
Not sure I follow Richard? :?: :?:
Author:  emsvitil [ Tue Feb 19, 2013 7:21 pm ]
Post subject: 
Would flipping over the crank gear help at all?

(maybe timing mark is on wrong side)
Author:  Fopar [ Tue Feb 19, 2013 7:23 pm ]
Post subject: 
How far from the inside end of the piece (the end that fits against the crank) to the back side of the gear. That is the part you are thinking of trimming, so you should find how much or if you even need to trim.

Richard
Author:  Rick Covalt [ Wed Feb 20, 2013 3:12 pm ]
Post subject:  Thrust Washer?
I spoke with Will and he mentioned making sure the cam lobes were centered in the lifter bores. After I removed the head and took a look, it appears that the cam could be shifted about .020-.030 towards the front to have them centered. By doing that it does help the 2 gears alignment issues some.

My question is does anyone know where I can get a .020 -.030 thrust washer? ID needs to be 2" outside can be 2 1/2 -3" I didn't know if anyone had any shims from something that may fit? Maybe from a rear or something.

Rick
Author:  emsvitil [ Wed Feb 20, 2013 5:07 pm ]
Post subject: 
Try www.mcmaster.com

search 'thrust washer'

quick search and I found 7 (depending on material) that are

2" ID
3" OD
.125" Thick


For thinner search

'shim washer'
Author:  emsvitil [ Wed Feb 20, 2013 6:26 pm ]
Post subject: 
You could put washers between the camshaft gear and block to align the gears where you want shifting the whole camshaft forward.

Then put some shims between the gear and the camshaft to shift the camshaft back where you want.

As long as the shims are thinner overall than the recess in the gear, everthing should be fine.
Author:  Rick Covalt [ Wed Feb 20, 2013 6:35 pm ]
Post subject: 
Quote:
You could put washers between the camshaft gear and block to align the gears where you want shifting the whole camshaft forward
Yes, that is my plan. I found exactly what I wanted to MacMaster Carr

Thanks ,

Rick
Author:  emsvitil [ Wed Feb 20, 2013 7:09 pm ]
Post subject: 
I also found this:

http://www.competitionplus.com/drag-rac ... -tool-set-


This easy-to-use tool set allows for quick and effortless measurements. Simply mark the cam lobe with a marking fluid such as machinist blue layout marker or dry erase marker, install the cam, and then place the tool in the lifter bore. Next, turn the cam over to mark a line around the cam lobe, and then remove the cam. Simply measure the distance from the edge of the lobe and change shims to achieve the correct lobe to lifter alignment. Safeguarding your camshaft is that simple with the Camshaft Lobe Center Marking Tool Set


My question is

What's the correct alignment?
You get a measurement, but I can't find a spec for this measurement anywhere.........
Author:  DadTruck [ Wed Feb 20, 2013 7:21 pm ]
Post subject: 
my first thought was that the lifter bore would be centered to the cam lobe,, i.e. the scribed line would be in the center of the lobe,, but then remembered that flat tappets need to spin as they wipe across the face of lobe,, and to do that they need to be slightly off center with respect to the lobe,,,,so
Quote:
What's the correct alignment?
is a good question..
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