JAKE ADJUSTMENT ON ISX

[Rawze]

(07-13-2019 )DosGatos Wrote:  Did the overhead from scratch; loosened up everything but didn't remove the shafts. I have about 60k on the new rocker shafts and had rotated the shafts. Don't keep notes so no clue what happened when I installed the replacement shafts.
Following the instructions starting with the flat ends set to the block and final torque to 90lb I have a consistent .090 +,- running clearance. Odometer is 835k so was expecting less. Looking over the head I see all the freeze plugs are unpainted. Can only guess the head was rebuilt but I have no service records from the original fleet or second owner.

that is much better. When they start getting below 0.030" travel from the detent position to the top of the valve stem, its time to replace the head.

[Signature620]

Why are you torquing the shafts to 90ftlb?? They are supposed to be 22ftlb + 60deg.

[Rawze]

(07-14-2019 )Signature620 Wrote:  Why are you torquing the shafts to 90ftlb?? They are supposed to be 22ftlb + 60deg.

I think 90 ft-lbs is about where you end up when you do the 22 ft-lbs + 60 degrees(one flat of the bolt head). Some people do it this way, does not really seem to hurt anything for the rocker shafts any ways. - 90 seems to be the minimum however,.. with the torque+ method, you will end up at roughly at 105 most of the time instead of 90, but 90 will hold it just fine.

opinion only...
- Personally,I don't know why the red maker states doing it this way for the rocker shafts, unless in the past they used stretch-bolts? -- My only other guess as to why it statres ti do it this way is so that the rocker shaft is fully seated against spring forces before fully tightening it?. So some moron does not tighten and torque one bolt at a time while the others are not even installed yet? -- Not sure, but these days, the retaining bolts are not of the stretch type, so I would think that a set torque would suffice just fine as long as someone does them all at 22 first.

- If unsure, use the torque+ method, find out what the average torque ended up being and set them all the same. Just don't do something like that for more critical components like say the head or bottom end bearing caps. those components use stretch-bolts and have a torque+ method for this very reason.

[DosGatos]

(07-14-2019 )Signature620 Wrote:  Why are you torquing the shafts to 90ftlb?? They are supposed to be 22ftlb + 60deg.

Recommendation of 90 from Hammerhead. I started with 22ftlb and worked towards 60deg checking the torque along the way. Turned out to be close. Went with 90 for convenience.

[Signature620]

My torque wrench measures them anywhere between 90 and 125 once the turn is completed. I'm not your boss but I think it's worth taking the extra few minutes for that torque turn method.