Cam to Crank Gear tolerances

i have my cam and gear installed on my build.
balanced cam gear with a torque cam.
WITHOUT any of the valvetrain installed, i have a .007 lash in the cam gear.
i have to do some math to find out the degree of variance.

but this seems a bit too much, what are your thoughts?

just trying to dot my I's and cross my T's

IH manual gives 0.0015 - 0.013" backlash, so you're within spec.

Never measured one myself. That does seem more than I'd really expect, though I don't see any reason to be too concerned. Maybe try a different gear if you have one and see what that one is at?

IDIoit said:

i have my cam and gear installed on my build.
balanced cam gear with a torque cam.
WITHOUT any of the valvetrain installed, i have a .007 lash in the cam gear.
i have to do some math to find out the degree of variance.

but this seems a bit too much, what are your thoughts?

just trying to dot my I's and cross my T's

Click to expand...

A bond...jsmes bond gear...

I know its off topic but did you ever consider decompressing your motor to be more like a 7.3 PSD?

since this is pretty much my first IDI build, i did not want to change too much.
i could have cut the pistons down, but it was not in the cards for this build.
im really really close to getting this back together.
only thing left is the valvetrain, which will be stock, vs. the roller rockers i purchased,
(they are still incorrect)
oil pump and pick up. to be cleaned and installed.
and then everything bolted back together.

sense the demise of my powerstroke, i wont beable to go as far as i wanted with it, this round anyway.

no mufflers said:

I know its off topic but did you ever consider decompressing your motor to be more like a 7.3 PSD?

Click to expand...

Tangent

I decked my pistons 0.015" to support higher boost. My numbers show that's good for about a 1 point drop in the CR, down to about 20.5. I think some folks have taken more, however you can't go down too much before it starts becoming very hard to start. It is also possible to weaken the piston crown dangerously if you take too much off, though i expect you'd have to be pretty aggressive for this to really be a problem. Biggest concern is going to be cold starting, IIRC someone went down to 18-19:1 and it wouldn't start without ether below about 70*. Taking too much off will also change the air flow in the cylinder & prechamber which could cause issues, especially if using a very high fueling rate. (as would be likely with high boost numbers). Stock the majority of the air is packed into the prechamber, so most of the combustion can happen within it and it completes as the gas flows out. With a severely decreased CR the prechamber will have a minority of the total air, so you'll get partial combustion within the chamber and essentially a mixture of high temp combustion gas and raw fuel passing out into the main chamber. I would expect this will result in the perchamber running hotter likely more erosion of the chamber throat possibly enough to cause damage over time.