I Need Engine Experts! 340 Roller Lifter and Pushrod Issue
I want to update folks on the status of this:
Regarding the significant angle between the lifter and pushrod:
This is what it is, and there is nothing really that can be done about this given the parts that I have. The angle is made worse by a taller lifter, so a solid lifter is a possibility to reduce the angle (and lift losses), but for this engine, the hydraulic lifter is the right way to go, especially given that this is a street driven car.
My measurement of the losses for this was likely in error. By calculation for this application, it looks like (all other things perfect) that the angle means you only get 94.6% of the cam lobe lift transmitted to the top of the pushrod. Not ideal by any means, but still workable. (Knowing this, I would definitely use 1.6 rockers in the future.)
Regarding rocker geometry:
I called and spoke with Mike at B3 Racing engines this morning. What a super guy and based on our conversation, I highly recommend him.
The rocker arms for this engine are contacting the valve stem in a decent spot, but the shaft is no doubt lower than ideal. His kits (custom made for each application) improve this geometry. The biggest gain, from my perspective, is that the improvement in rocker geometry means the valve will spend more time when it is near fully open. Ultimately, this means better flow, and we all know our engines improve with better flow.
The gentleman that now owns this engine needs to make decision if he wants the kit from B3 Racing. The biggest issue we have now is time so he may go with the geometry as it is and upgrade later in the year. If he does this, the downside will be that he will need to buy another set of pushrods. Either way, I will do some extra clearancing of the heads to hopefully cover any future relocation needs, be it in 3 weeks or 3 months.
(P.S. I will almost certainly order one of these kits for my 400 based stroker motor as I think they will improve my geometry on that.)
Now time to make progress with getting this thing running!
Again, I want to offer a humble and sincere Thank You to everyone that contributed ideas! :thumbsup: