Comparing some of my original hipo lifters (C3OZ-6500-A) to a set of Ford Motorsports 289/302 lifters (M-6500-A302) and note the orifice in the Motorsports lifter is much smaller in diameter. Anyone know Why Motorsport made the orifice change in the later lifter design?
Making the hole smaller would increase the oil pressure.
Quote from: Royce Peterson on April 29, 2024, 10:51:52 AMMaking the hole smaller would increase the oil pressure.
My guess would be that it was done to decrease the oil flow to the rocker arms. I think that the smaller diameter in the discs would increase oil pressure to a very small degree.
Frank
Flow and pressure are inversely proportional so that would be the case.
I put the question to Motorsport and got a bureaucratic non-answer. "The A302 lifter was an off the shelf purchase from Johnson." No comment or awareness of any Ford specifications. LOL
Quote from: csxsfm on May 02, 2024, 02:11:08 PM"The A302 lifter was an off the shelf purchase from Johnson." No comment or awareness of any Ford specifications.
That answer tells me to go direct to Johnson and avoid the upcharge for putting the "off the shelf" part into a Motorsport box.
https://johnsonlifters.com/Products/Mechanical-Flat-Tappet-Lifters/5215#3204128-applications
After delving into the grey matter of what's left of my brain, I have come to the conclusion that it probably really does not matter what the size of the hole in the lifter disc might be unless it is smaller in diameter than the hole in the cupped ends of the push rod. The reason being is that the smallest hole or orifice in the lifter/pushrod/rocker arm is what is going to dictate the flow/pressure of this oiling circuit. If I remember correctly (big if) the smallest hole or orifice is the pee hole in the pushrod socket of the rocker arm that piddles oil on the rocker ball and indirectly down to the valve guide area. Please correct me if this isn not the smallest orifice. SOOOO, if all of the internal lifter pieces are similar in both of the lifters that the original OP compared, disc hole diameter size is probably a moot point.
Thanks, Royce for the good discussion and for FORCING me to think.
Frank
But if in either case if the "hole" in the lifter shell presents a greater flow capacity than the intended leakage rate down-stream then perhaps there's a different intention?
Perhaps this dimension was just carried over from the hydraulic lifter, here adopted so as by presenting a smaller exposure to the engine oil gallery the valving in the lifter isn't so influenced by pressure fluctuations and with reduced flow rate capacity into the lifter's hydraulic reservoir better control is had and reduced tendency for "lifter pump-up"? :-\
Heck, I don't know, but I thought it sounded good anyway? ::)
Scott.
I think the Ford guys may have already answered the question. They bought an off the shelf part that was different from what the engineers had designed. They use the same part number - because it doesn't matter. Flow and pressure are likely unaffected by the different hole size.
FYI the specific "off the shelf" lifter Motorsport used was the A-2000 from Topline/Hylift/Johnson.
Why purchase from Ford who no longer manufactures these solid lifters, but buys them from an outside ( Johnson ) source.
Then Ford marks them up for double of what you can actually purchase these on the after market yourself from a reputable vendor ?
Also keep in mind that valve springs are cooled by the oil flow and not enough can cause them to get hot and fail faster than they would otherwise. That is the main reason that Nascar engine builders put oil sprayers under the valve covers to help keep the springs cool.
Roy
Quote from: TA Coupe on May 02, 2024, 11:28:06 PMAlso keep in mind that valve springs are cooled by the oil flow and not enough can cause them to get hot and fail faster than they would otherwise. That is the main reason that Nascar engine builders put oil sprayers under the valve covers to help keep the springs cool.
Roy
Big Plus 1
Quote from: FL SAAC on May 02, 2024, 05:27:37 PMWhy purchase from Ford who no longer manufactures these solid lifters, but buys them from an outside ( Johnson ) source.
Did Ford Motor Company actually manufacture the original lifters for these engines? Somehow I just don't think so. :-\
Scott.