Got done with a 103" build:

DarkHorse balanced crank and rods & Lefty bearing
.010" cleanup of the cylinders
CP forged pistons (10.75CR)
Heads ported and polished with new valves (recessed back to 10.5:1CR)
MLS head-gasket
S&S Quickee pushrods (setup for zero lash and then the recommended 24 flats)
S&S roller tappets
S&S 585 cams
S&S cam plate and oil pump

Primed up the oil pump by leaving the gas connection unhooked and cranking for 10-15 seconds and repeated a few times. Connected the tank and fired it up...the rear cylinder seemed to quiet down normally as the lifters pumped up but the front cylinder continues to clatter sounding like the lifters are failing to pump-up.

note: oil pressure appears to be in the normal 27-30PSI range for a S&S pump/ cam plate combo

Any ideas or suggestions?

 

Sounds like classic lifter pushrod chatter. Either one of those front lifters failed out of the box which can happen but real rare or zero lash wasn't found correctly and you need to extend those pushrods a little more.

 

I'll give that a shot and reply.

 

Yea That definitely sounds like a lifter failing to pump... recheck the preload and set to 27 flats. Then take it for a good 20 mile ride. Lots of times there is one liter that just wants to be stubborn. Don't beat on it just ride smooth. There was another guy just a week ago had he same problem and was chasing everything. Finally took it out for a good ride and that one stubborn lifter finally pumped up...

 

Looks like the front exhaust pushrod may have been riding on the EZ start ledge or the lifter could have just burped cause it was pretty loose in there when I double checked. Now I've gone back thru them all and am just waiting for the obligatory bleed down to ensure they spin by finger pressure after adjustment.

...thanks for the feedback

 

We like to load the lifter to .140", or 27 flats/4.5 turns with a 32TPI pushrod thread, and .200" total lifter plunger travel.
Scott

 

Take a look at the pushrod tubes also. Only takes a little rubbing to make a lot of noise.

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Thanks guys!

Took the advice and went with 27 flats (4.5 turns) and double, triple checked my work...it fires right up and purrs.

 

Cool...... Glad to hear... Ride safe man....