lifter question

[blacdog2]

hey guys, well just got the new engine for my buddies 68 general lee charger ( 383) and have a question. it looks like the engine company pre run the engine due to oil being in it in place but, im used to chevys that have rocker arm studs to adjust the valves but see the 383 doesnt have them. so im assuming theres no adjustment or way to set the lifter preload?? like said im new to the in depth mopar build and appreicate all the help

 

[Cranky]

If the builder checked the preload to make sure it's within specs, then it should be good to go but if the heads were milled or a different head gasket was used, it can change the preload. Again, hopefully, it was checked before assembly. If preload is too tight, you can add shims under the rocker shafts....but if it's too loose, then you have to get longer pushrods or install adjustable rockers. 90% of my builds get adjustable rockers.

 

[racedodge]

if he is running the stock rocker arms with shafts, and there was not any head machining done.. then NO there is no adjustment.

the only time you have to REALLY worry about lifter preload on a mopar is when running:

1. adjustable rocker arms
2. head has been machined to close chamber size (i.e. milled)
- this causes for the pushrod length to be custom, hence checking lifter preload is mandatory

if neither of those things are taking place, and the pushrods you have are the OE stock (correct) length.. then dont worry about it.

hope that helps.

 

[Cranky]

In his case, the builder should be responsible for any screw ups but any time a new cam and lifters are installed, the preload should be checked. Not worrying about new parts and machine work is the fastest way to crater a new engine....just because the box or someone says the parts fit doesn't always mean they do and the way things are nowadays, that's more true than it was 30 years ago.

 

[69 Runner]

The slick way to deal with preload (especially if you're running the car in a class that doesn't allow anything other than O.E. rockers) is adjustable PUSHRODS. They are cheaper than adjustable rockers, and will go longer or shorter than stock.