Roller or Flat Tappet? Mild 440 build prep

[Thunderdan]

Getting an engine build plan together for my '78 Monaco A38/E86. The engine is the factory High endurance cast crank 440 and all appears to be original and will be disassembling soon to verify. The rest of the drivetrain is original; 727 and 9.25 diff with the 2.71 open gears. The objective here is torque, durability, and enjoyment, not 6000+ RPM blasts as I'm keeping the 2.71 gears. Planning for ~400-425hp with ~9.25 compression and may go with TF 240's or work on refreshing the original 452's with some mild porting (I have some off a donor motorhome longblock that I can use to save the originals) with reconditioned factory crank/rods and KB pistons with a complete balance as well as RPM intake and headers. While I know it'll need the proper springs regardless, my concern with a relatively mild build is whether a flat tappet cam will suffice in this build- and last - or if a very mild hydraulic roller will be needed to avoid the real chance of eating a cam/lifter and pulling it all back out again after the gamble loses. I plan to run high-zinc oil either way and I's fully aware that a roller cam requires $2K+ in an investment in the valvetrain over a flat tappet with pushrods, distro gear, and cam button hardware, but will it be necessary at this moderate RPM and mild power level?

 

[PRHeads]

In my mind if comes down to budget, and your comfort level with the risk of a HFT cam failure.

For sure, from a power standpoint, a HFT would get it done.

 

[furious70]

I would not invest in a roller for that build personally, and my next build is using a small solid with edm lifters. Hopefully I don't regret it

 

[Kern Dog]

I've used the Mopar Performance 528 solid with EDM lifters....it held up fine until like an idiot, I switched to a modern oil that claimed to have "Extra ZDDP".

I was told later and I found supporting evidence through published articles that any oil with an API rating after SG has a strong detergent package that serves to wipe away the ZDDP as fast as it touches the metal. In short? Oil like this offers far less protection than dedicated classic engine oils do.

Better oil?

 

[Thunderdan]

I've used the Mopar Performance 528 solid with EDM lifters....it held up fine until like an idiot, I switched to a modern oil that claimed to have "Extra ZDDP".

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I was told later and I found supporting evidence through published articles that any oil with an API rating after SG has a strong detergent package that serves to wipe away the ZDDP as fast as it touches the metal. In short? Oil like this offers far less protection than dedicated classic engine oils do.

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Yea, I've read that and I believe the The Oil Geek also had a YouTube video noting that the detergent package is the issue with the newer high zinc oils not protecting the flat tappet cam/lifters.

I pulled the factory lifters out of the motorhome 440 and they are in fantastic shape so I'm tempted to have those resurfaced to use in combination with a mild hydraulic flat tappet, which may eliminate the risk on the lifter side, but that still leaves the risk with a new cam itself being the failure point and, again, even the "high ZDDP" oil not doing its job.

 

[lewtot184]

I do similar builds to what you're wanting. First, i'd ditch the 425hp goal. To do 425hp net you will need more than TF heads by themselves. I think the TF's are over kill. Keep in mind the engine you have now probably nets about 250hp. A 375-380 net hp would be a simpler and more satisfying goal for a mild build. Chase torque with that tall gear. Stealth heads, a CH4B, 800avs, and a moderate cam (you will have upgrade exhaust for a lumpy cam). Picking up a net 125hp, plus 100lbsft of torque, without getting stupid, would be fun. Actually, you could do this with work on your iron heads and kb184 pistons. Alum heads will need a flat top piston.

 

[JARRETT LYNCH]

The readline oil tested pretty bad on the oil geak youtube vids I watched. Amzoil tested pretty good. I like the Amzoil classic oil.

 

[Kern Dog]

The readline oil tested pretty bad on the oil geak youtube vids I watched. Amzoil tested pretty good. I like the Amzoil classic oil.

In retrospect, I should have researched before switching. I had no idea that such destruction could be the result. I ended up pulling the engine to go through it all. It turned out to be a better running and performing engine than it ever was so while it was not convenient, it did happen when cash reserves were good. I rebuilt the front suspension, added bigger brakes too.

 

[Geoff 2]

Get your factory lifters refaced & try & find a cam company that has [ or will grind ] a cam for Chrys 0.904" lifter size [ Comp does, just had one ground ]. The area under the curve will be close to a mild hyd roller cam, much less expense & less component parts that can fail. Using a Dremel on the lifters, grind a small groove from 1/8" of the lifter base to the oil groove for extra oiling. Use a cut-off wheel, go about 0.020" deep, not critical.

 

[Rebelrouser]

I would not invest in a roller for that build personally, and my next build is using a small solid with edm lifters. Hopefully I don't regret it

From my experience the issue is not the oil or oiling it is the way the tapers are ground on the cam lobes and lifter. You can take a small file and cut a groove in the block lifter hole to increase the oil flow. Used to do it on engines with big flat tappet cams worked very well.