Engine Builders - Minimum Roller Lifter / Dogbone Overlap?

[marjama]

Hey gang - a question for the engine builders here:

I'm working on building up a 363W with a custom FTI cam. I'm on round 2 on the camshaft due to issues with the first grind, and the second cam that was delivered has a much smaller base circle. When installed at TDC the lifters drop below the top of the dogbone leaving ~.040" overlap between them. Will this work?

Only realized this issue as I was planning to assemble for good. If it's not going to work I'd rather figure that out now than when I try to start the engine!

The engine is a Ford Boss 363W short block, Ford R302H lifters, stock dogbones and retainer. I'm generally pretty frustrated with FTI and the delays I've experienced and the total lack of customer support. More on this later in my build thread (which hasn't been updated for over a year!), but this is the engine for my Bronco. Just trying to keep it creeping along and get some parts out of boxes and where they belong!

Thanks!

 

[Broncobowsher]

I would be sending that picture to the cam grinder.

I can't find my last build photos, but I recall the lifter was above (not below) the spider. That looks way too low to me, and by you questioning it I am going to say it looks wrong to you as well.

That small base circle grind will probably work fine with a link bar style lifter. Which will probably be what the cam grinder will be quoting when they say it has worked fine in the past. I'm waiting for the suggestion to mill down the tops of the lifter bosses to get better dog bone engagement.

It might be time to get a new cam grinder.

 

[73azbronco]

Not good, call cam and engine guys.

 

[DirtDonk]

x3 from here. And I'm not even well versed in roller geometry! But that just ain't right no matter how you look at it.
Almost looks as if you could turn the dogbones over and get some different engagement. But that's not the way, and it's probably not doable anyway with that design.

And are you using stock replacement lifters? Does that manufacturer make an extra long version, perhaps for this very purpose?

Paul

 

[bronco italiano]

Perhaps the cam was intended for the link bar type lifters

 

[Broncobowsher]

Perhaps the cam was intended for the link bar type lifters

That was my thought as well.
They took a stock cam and reground it. Since you can't make the lobes bigger, they cut down the base circle. That makes the lobe higher off the base circle. Which is fine most of the time. But you are finding one of the times it isn't. I would even start questioning the alignment of the oiling ports to the lifters.

 

[marjama]

I'm with you guys. We'll see if the cam grinder agrees.

The cam came from FTI (very well known in the SBF world), and he had all of the specifications for the engine. Stock dogbones + R302H lifters which tend to be slightly longer than factory rollers. I don't think I should have to spend even more on new parts to fix this. The first cam he sent me was a larger base circle and worked perfectly with the dogbones (even with ~.600 lift). It was off by ~2° on LSA and he agreed it wasn't close enough. The first cam took a couple of weeks to arrive. The replacement only arrived after many months and a call to my cc company. His billet cams are now ~$580 shipped. I have pretty high expectations at that cost! I also get that replacing a custom cam is probably a real pain since it may not be likely to be easy to resell quickly. We will see how he responds - haven't had anyone say ".040" is plenty!"