Quote: Joe, Wondering if you might add some thoughts about the development of the Hemi Pro Stock engine during your time with the Rod Shop, Mopar Missile and other programs at Chrysler, as you had a unique insider perspective . The Chrysler program resulted in some of the most innovative developments such as the crank trigger ignition, smart oil pan designs, high lift roller camshafts, etc., and common sense ideas like milling all of the un-needed weight from the cylinder block (bosses, freeze plug bump, webs, and even the thickness of the water jacket), restricting oil to the top end of the motor (less oil to the valve train means less has to get past the rotating assembly to get to the oil pan, re: reduced windage), etc. Just to get the reflective thoughts flowing, here are some questions:
1. Even with all the innovation of the Chrysler Hemi program, it seems like there was a reluctance to move from the NASCAR steel rod/heavy piston combo to an aluminum rod/light piston combo similar to the Ford 351 Cleveland, SBC and BBC and AMC. Any comments on this? Was durability the issue? 2. The dry sump oil system certainly adds weight to the front end of the car, but was probably a necessity when you are talking about super low cars such as Ken Van Cleve’s car, the Missile and even Carlton’s black B/A car. Any idea on how much horsepower was gained with the dry sump over a 7” oil pan, and was it enough to offset the added weight? 3. When did titanium valves first start being used in the Hemi’s? Thanks! Mark
Mark,
From my perspective, the PS Hemi development that was going on during the early 70's was a two step process. There were a lot of good engine guys out there running PS Hemi engines. Just look at what each and every team did and the success that was generated by their efforts. Absolutely, the Missile team led the way with the test program to try the new cams, piston technologies, and a ton of other innovations, but pretty much each team built their own engines utilizing the stuff that Chrysler fed them PLUS their own innovations and engine building techniques that became their signature. For instance, if Jake King, Dick Landy, Arlan Vanke, or Butch Leal felt they had a better way - then so be it and that is what they did. Sometimes, we had some bits and pieces on the car or utilized in the engine that had not quite made it out to the rest of the group and maybe that was one of the reasons we were so successful especially in the '73 PS season, but the rest of the teams would definitely be totally up to speed within the week so they too could use the same stuff if they chose to do so. What I guess I am attempting to say is - first, the Missile broke the ground development wise, and secondly - the Chrysler PS teams utilized the Missile data PLUS used their experience, skill, and techniques to further improve the engine development foundation we provided.
Now - for your questions... 1. I am probably not the best person to answer engine related questions but I do think that durability was an issue with aluminum rods. I remember when I was with Fons and the Ramchargers built a motor for us to test out in California. I am pretty sure it had aluminum rods but it broke after only a few runs. Our Missile engines used the steel rods and given the reciprocating weight of the piston / rod assembly, we had to change bearings every 10 to 12 passes. The pistons alone weighed a ton. It made for a lot of work but the reliability was alwasy there. To the best of my memory, we never broke a rod or had significant damage to a Hemi engine. Now we did tip some valves into the top of the piston ever so slightly now and then...but that was the price you pay. 2. The Missile Duster did not use a dry sump system. We used a deep oil pan with Mr. Hoover's kick outs and a swinging pickup. That was our standard. Using a dry sump was not yet on our agenda. Later, our 'A' engine program was going that direction but not our Missile deal. Also, I am not sure if Donnie used a dry sump on his B/A car or not. Oldfield may know and I will ask him. As far as hp gains from dry vs wet I honestly don't know, but I am sure the gains far offset any weight differences. 3. The question on Titanium valves is not something I actually know the answer to. I will ask Ted Spehar - he remembers all that stuff. My time was spent lashing valves - I was only in the engine room long enough to pick up more bearings and pick up or drop off engines for rebuilds...
