Lunati Hydraulic FT Cam users..........

I have a Lunati 10200704 (60404 when I bought it) in my 340, up until a little over a month ago I was running it with the Lunati cam kit "high performance" lifters. Those are the ones with the wire retainer. I put about 25k miles on the engine with them. Cold start up if the car had been sitting more than a day or two it always had a little bit of a lifter rattle for a few seconds until the lifters pumped up. They always did, it always ran fine, but I never had a ton of confidence in those lifters just because they always seemed to leak down faster than they should, at least IMO.

A few weeks ago I broke a pushrod. Not bent, this is a Smith's Brothers pushrod and it just flat out snapped clean off right at the end of the pressed in ball down at the lifter end. No warning, no changes, fired it off to go to work and just like that it was running rough. And no obvious damage to the outside of the push rod to indicate it hit anything either. I was suspicious of the lifters because I never really liked them, but again, I hadn't had any real issues with them and nothing had changed. So I sent the push rod back to Smith's and they sent me a new one, said they looked at it under a scope and it looked fine, one of their senior guys said he hadn't really seen anything like that and they weren't sure what happened. At least according to the guy on the phone, but I don't have any reason not to believe them as they warrantied the thing anyway. So I put it back together with the new pushrod and fired it off after inspecting things as best I could without tearing it down further. The car had been sitting a couple weeks at that point, so I expected the cold lifter rattle and sure enough I got one. Except louder, and they didn't pump up. For a lot longer than I was comfortable with. I shut it down, tried again, same thing even with a cold oil pressure pushing 70 psi. Nope, lifters done, not pumping up. I'm not a fan of coincidences, so, that pushrod probably belonged to a lifter that had bled down completely.

I replaced them with a set of Lunati Micro-trols, so far no issues and no cold start lifter rattle either. But only a couple weeks on them at this point. I inspected the cam and old lifters when I pulled the intake to change out the lifters, the cam looked fine and looked right for about 25k miles. The lifters, not so much. They weren't flat, but, they definitely looked like they were more than 25k miles old. Hard to explain, they didn't hurt the cam any and they weren't worn out, but they were pretty tired looking for only 25k miles. And when I pulled them none of them were pumped up, but, I waited to tear into it until I had the replacement lifters so that was kinda expected. The lifter on the pushrod that broke initially seemed the same as the rest of them - no damage, no less resistance, nothing out of ordinary compared to the rest other than generally looking more tired than a 25k mile lifter should look IMO. The micro-trols looked great, definitely a higher quality lifter straight out of the box compared to the HP ones.

My 340 has a 9.8:1 compression ratio, it has ported 308 heads, the recommended Lunati double springs to go with the 704 cam, Hughes rocker shafts with ductile iron adjustable crane rockers (1.5), Smiths pushrods, Eddy air gap intake, 750 Holley DP, Doug's headers, high volume oil pump, Milodon road race pan with a windage tray, pushes 70-75 oil psi cold and about 30 psi hot idle with Brad Penn 10-30w. It's my daily driver so that's why it has a hydraulic cam, not a weekend only or strip only car that I want to be adjusting rockers on all the time with a solid lifter set up. I have run solid lifter set ups before, they're not a big deal either but this one is going to stay hydraulic unless I keep losing lifters. Hopefully the Lunati micro-trols will hold up longer than the wire retainer HP's did and I can revisit the whole hydraulic vs solid vs roller when I build the next engine for it.

Just my experience with them, I'm not a professional engine builder or anything.