proper pushrod length

[Texas charger 73]

I'm building a 360 with stock bottom end, Hughes whiplash hydraulic cam with sidewinder aluminum heads.. fel pro 1008 head gasket(0.039 thickness).. i have stock stamped rockers or a choice of 273 adjustable rockers.. i need to find correct pushrod height as I'm unsure if stock pushrods will work anymore... I'm new to this and i haven't really messed with adjustable rockers much.. i have both comp adjustable push rod checkers...ball to ball and cup to ball from 6.800-7.800 length... any tips or tricks to make sure i do this correctly?

 

[440Coronet500]

Since you have a hydraulic flat tappet camshaft you'll need preload on the lifters. You should install each set of rockers and measure what length would give you zero lash. To get the desired preload on the lifters just add that amount to the length. On your adjustable rockers only 1-2 threads should be protruding out the bottom of the rocker. I'd also recommend replacing the original locks on those 273 adjustables with a set that has lock nuts. 440'

 

[747mopar]

^^^ Like he said, 1-2 threads showing.

 

[Texas charger 73]

Since you have a hydraulic flat tappet camshaft you'll need preload on the lifters. You should install each set of rockers and measure what length would give you zero lash. To get the desired preload on the lifters just add that amount to the length. On your adjustable rockers only 1-2 threads should be protruding out the bottom of the rocker. I'd also recommend replacing the original locks on those 273 adjustables with a set that has lock nuts. 440'

How do I get and/or determine zero lash?

 

[Curiousyellow71]

http://www.b3racingengines.com/techpages/MoparRockerArmGeometry4.asp

This is good resource when your doing anything custom.

 

[Texas charger 73]

This is what I came up. With for adjustables with cup/ball pushrods.

Closest pushrod length I found is 7.342

 

[Texas charger 73]

Two different hydraulic. Lifter preload. Everything I have read says 0.020-0.040, but hughes says there lifters are 0.080-0.090

 

[Curiousyellow71]

Turn the engine and do each valve...When the exhaust valve starts to open adjust the intake. When intake valves is all the way open and starts to close adjust the exhaust.

Tighten till 0 lash and you will start to compress the lifter.
Pretty common to give them one more turn in on a hydraulic cam and be towards the top end of the travel. Sometimes it takes more if the lifters still chatters.

 

[Texas charger 73]

here is what i came up with for the adjustable 273 with Hughes hydraulic cam
6800 length pushrod collapsed
8 turns out @ 0.050 plus 6.800 equals 7.2
plus Hughes lifter preload of 0.090 plus 7.2 equals 7.29
minus 0.0150 for cup gives me total length of 7.14

does this seem correct...i found proform pushrods 66417c with length of 7.190.. these should work

 

[RemCharger]

8 turns out on the adjusters? .090 compressed in the lifters? Put up a pic of the assembled rocker/pushrod..

 

[Texas charger 73]

8 turns out on the adjusters? .090 compressed in the lifters? Put up a pic of the assembled rocker/pushrod..

8 turns out on the adjustable pushrod checker... 0.090 preload on the lifters in per hughes specs, its there cam and lifters

 

[Texas charger 73]

8 turns out on the adjusters? .090 compressed in the lifters? Put up a pic of the assembled rocker/pushrod..

here is the sheet from hughes.. i have cast block aluminum heads and lifters #5001 it says 0.090-0.095 preload