Lifter seat height

[supertruck]

In the middle of my 340 build, I've decided to go from a hydraulic cam to a solid. Since I've already ordered the custom length push rods for the hydraulic setup, I want to avoid buying new ones if possible. I'm using the PRW adjustable roller rockers. The Crane anti-pumps I have are 1.580 seat height. The Comp Cams solids are 1.79 or 1.63 seat height. Am I correct in wanting the 1.63 Comp Cam solids since they are closer to what the hydraulics are, and will most likely work with the pushrods and adjustable rockers I have now? Or am I totally off base on this? Thanks for any help.

 

[mod5v]

If the pushrods are the ball-cup style you can probably get away with the .050" difference but did you take into account preload on the hydro lifter? If the Ball-Ball style the pushrod is more critical in the rocker area as there is a limited amount of undercut in the adjuster for oiling. also the pushrod length will have an effect of where the roller rides on the valve stem.

 

[supertruck]

Thanks mod5v. These are ball-ball pushrods. The pushrods were originally measured by taking the length at zero lash with the lifter not pumped up, then adding .040 to them. I guess to be safe I'll just get the lifters that come with the Comp Cam kit and re-measure. If I need new pushrods I'll order them or see if Smith Brothers can cut these down as needed.

 

[72Dart6pack]

Call & speak to Don. He made me a set a few weeks back for less than the Race shops charge. Oh yeah! He is the manufacturer for most of the aftermarket guys anyways. Ask nice and he will throw in 2 spare ones. Nice guy. Nice place. When I was there. He had 15,000 push rods in a single parts bin. That was for one of the places you listed.
Home - OE Push Rods - Manufacturer & Distributor

 

[B3RE]

Bill, I explained to Pete the issues you would have making that change. It isn't going to be just a pushrod length change. I told him to stay with the hydraulic and it would be fine, but he didn't seem convinced.

 

[yellow rose]

At .060 difference I'd measure again an order new pushrods. I'm pretty anal about that stuff. In the machining world, .060 might as well be 6 feet.

Some will scoff at that but most of them aren't machinists.

It's cheaper to do it right the first time, than to do it 2-3 more times later. And much more stressful.

 

[72Dart6pack]

Push rods are cheap. Get a new set. Follow my link. Order from Summit & ask them to throw in a few extra push rods no cost & see what they say?

 

[supertruck]

Thanks for all the help guys, especially Mike at B3 for putting up with me. I'm going to stay with the geometry correction kit until I get it right. The valve tip sweep is so good with his spacers. Both Pete, my engine guy, and I are just not happy with the amount of movement we're getting with the hydraulic lifters, that's why I decided to go with a solid cam. I'll measure again for the pushrod length and get new ones. This might all be due to a lack of Mopar experience. All my engine building is helping Pete with my solid cam race motors. Pete has plenty of experience in building street and race motors, but not Mopars. That makes us both a bit leery when we see something we're not used to seeing. Again, thanks for all the help.

 

[yellow rose]

Thanks for all the help guys, especially Mike at B3 for putting up with me. I'm going to stay with the geometry correction kit until I get it right. The valve tip sweep is so good with his spacers. Both Pete, my engine guy, and I are just not happy with the amount of movement we're getting with the hydraulic lifters, that's why I decided to go with a solid cam. I'll measure again for the pushrod length and get new ones. This might all be due to a lack of Mopar experience. All my engine building is helping Pete with my solid cam race motors. Pete has plenty of experience in building street and race motors, but not Mopars. That makes us both a bit leery when we see something we're not used to seeing. Again, thanks for all the help.

That's what I always say...Mike is a damn good guy.