[Jeepbeeper]

put in a new 151 iron duke... not even 1000 miles on it.
Has an intermittent knock that sounds like a lifter.
We pulled all the lifter rods, and rolled them on a flat glass
surface, and none are bent and none have flat spots on the tips.
All lifter rocker arms are torqued at 20 lbs. as manual says
between 17 and 23 lbs of torque.
New oil 10/40 weight in engine.
Valve springs new and at 100 lbs. resistance. So they are
at required test lbs. of push back.
The sound appears to be comming from possibly the rear of the
engine. But i cannot pin point the source exactally.
We dont think its a rear bearing , because there is not a constant knock. The knock is loud at start up, and dissipates
to a , (what i would consider a lifter ting sound),
In all my mechanical experiance..this one has me stumped.
The sound seems to travel around different locations of the engine...but definately near the rear.
Does anyone think the noise could be within the clutch assembly?
I'm really haunted with this traveling sound.
ANY HELP would be welcome, as this engine is NEW, and
should NOT be making any noise at all.
Thanks in advance!\

[John C]

Stamped steel rockers may be your problem. I had an issue with my 258 tapping and it turned out to be one of my "new" rocker arms. Stamping specs seem to be rough at best. After the tapping issue found as much as .006 difference in the set for the 258. Apparently they rely on the hydraulic lifters to take up this difference, it doesn't allways work. May not be your problem but worth looking into.

[Jeepbeeper]

Originally Posted by John C

Stamped steel rockers may be your problem. I had an issue with my 258 tapping and it turned out to be one of my "new" rocker arms. Stamping specs seem to be rough at best. After the tapping issue found as much as .006 difference in the set for the 258. Apparently they rely on the hydraulic lifters to take up this difference, it doesn't allways work. May not be your problem but worth looking into.

Thanks John C
I will look into it this sunday...though i dont have hydrolic \
lifters...so i cant gadge the suckers lol.
One time when we started the jeep early in the morning,
it LOUDLY BANGED for a few strokes, then went to that loud \
tapping sound, and then within 10 seconds of starting it just
ticked off and on like a lifter..
ok..the rocker arms bolt on at 20 lbs. so you can tighten them
forever, and they dont do any more.
the rods are clear inside..i held them to the sun, and saw light..
and I'm at a loss right now...I'm going to check the crank, and drop the oil pan and see if everything is tight...after i do that,
I dont know what to do.

[John C]

If you don't have hydraulic lifters then it isn't lifter tap. Could be a worn lifter bore. Once you get that oil flowing it will quiet it down. I hope this isn't the case because a bad lifter bore means tear down and machine. What does your oil presure look like? Don't count out a bad cam lobe, solid lifters can wipe a lobe quickly if you have a dry start. You can make a tool to measure push rod length. Take a turn buckle (like what you use to level a screen door) and put a piece of all-thread in one side. Insert it into the push rod tube. Turn the nut until it is snug on the rocker arm. Pull it apart and measure the distance with a dial caliper. Measure at point where cam has no lift. Also use this set up to put a dial gauge in the rocker arm tip to check lift and rocker arm consistency. Takes time but answers a lot of Q's. This method is how I found the inconsistencies in the 258 rockers.

[Jeepbeeper]

Originally Posted by John C

If you don't have hydraulic lifters then it isn't lifter tap. Could be a worn lifter bore. Once you get that oil flowing it will quiet it down. I hope this isn't the case because a bad lifter bore means tear down and machine. What does your oil presure look like? Don't count out a bad cam lobe, solid lifters can wipe a lobe quickly if you have a dry start. You can make a tool to measure push rod length. Take a turn buckle (like what you use to level a screen door) and put a piece of all-thread in one side. Insert it into the push rod tube. Turn the nut until it is snug on the rocker arm. Pull it apart and measure the distance with a dial caliper. Measure at point where cam has no lift. Also use this set up to put a dial gauge in the rocker arm tip to check lift and rocker arm consistency. Takes time but answers a lot of Q's. This method is how I found the inconsistencies in the 258 rockers.

it does have hydrolic lifters..sorry..im working on two engines right now lol.
ok im talking bout the 151 iron duke.. i can pull off the side
block cover and expose the hydrolic lifters...but what good will
that do me...crap im at a loss still.
I'm prayen it wont have to be pulled ..the engine...just put it in 2
months ago lol.
Ok. sunday i will rip it a new butt..and see just what the heck
is going on....im feeling there may be a dry spot somewhre..but only at start up...being a new engine..i bet there could be a oil return hole partually pluged...or I just might find a gremlin
in there drinken budwisers on my cam shaft!
Bas****!
Lemme drink another iced tea, and hope for the best..
Wrench in hand.. and a mean attitude..i'm bout to
go hunten wabbit.
thanks john c.
Hey..measuring the rods...what could it be if all the rods measure
the same... clue me in man....i aint got time for this bull right now lol.
thanks for your help...I'm not ASE certified. but my father was
a mechanic....he is just never home to answer my questions at
10 o'clock at night lol.
thanks man in advance!