Author Topic: Gnarly4X's 22RE Rebuild  (Read 195520 times)

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Gnarly4X

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Re: Gnarly4X's 22RE Rebuild
« Reply #900 on: May 08, 2017, 04:45:50 AM »
UPDATE MAY 8 - AM

Without degreeing* the 261C cam…  and it annoys me to think I should have to go to the extra expense and time to degree a camshaft to prove its specs are correct as published by the supplier.  BUT… that* is the suggested safe bet.

After more physical inspection of the stock cam profile.  Using the typical FSM procedure for adjusting valve lash, the measurement with a feeler gauge will be at the following location on each cam lobe:

From the front - in degrees from base of circle (opposite lobe peak)

#1 Intake….…90
#2 Exhaust…..90
#3 Exhaust….180
#4 Intake……180
#5 Intake……180
#6 Exhaust…180
#7 Exhaust….90
#8 Intake…… 90

Since the noise I’m hearing seems like rockers?, and knowing that the lash measurement on number 1 cylinder, which is done at 90 degrees from lobe peak, measured tighter than cam spec - .007” and .009” - after re-adjusting the lash at the base of the circle.  So… that may indicate that the ramp of the lobe on the 261C starts earlier than the stock cam.
In other words, if the ramp has started at 90 degrees from base, the lash adjustment made at that location will make the base circle measurement looser, a valve lash greater than the cam specs…. possibly causing excessive rocker tick?
In cam profile design, it makes sense to slow the closing of the valve before it hits the valve seat… helping reduce valve bounce and slam noise.

I am assuming the 261C has the same 110 degree lobe center as the stock cam.

The only two cylinders, that are adjusted according the procedure in the FSM that could affect the “correct” cam spec adjustment are 1 and 8.

Tod at engbldr did, in fact, suggest that I adjust the lash at the base of the lobe circle.  So, I will re-check and re-adjust the valve lash at number 1 and 8 cylinders and see if that makes any difference in the noise I’m hearing.  I will also carefully not over-torque the rocker cover.

NOTE:  For those of you who are running aftermarket performance cams in a 20/22 and may not be savvy on this procedure (base circle valve lash adjust), for this engine you only have to do this for number 1 and number 8 cylinders… unless otherwise recommended by the cam supplier.

Gnarls…. that’s just my opinion, it may be worthless.
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

 
 
 
 
 

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