Looks like I need to check out the forum it little more often. My first two roller cams were just mopar stock cams reground by OC.
I could usually get maybe 55 to 60 runs before the lifters started digging into the camshaft lobes. But that was a whole sesaon for the wagon. I did purchase two steel cams from OC and installed one last year and ran the car with no problems. Think that cam was around 280* duration @ 50 and .660'' lift. Installed height is 1.900 so their is a good selection of valve springs to pick from.

So... the problem is. Ken gets these cams from LSM and they are kind of hard to deal with. Once they make the cams, that are all the same pattern, are only roughed in, Ken has to finish grinding them and there are only small changes he can make. Lobe centers, duration, lift and stuff like that. Finding the cam profile to meet everyone's needs might be a challenge. Also LSM needs an order for 20 cams before they start. Ken doesn't want to get stuck with all the unsold cams so it would to be like a group buy. right !!

You can get more power from a roller but it's a lot of extra money that could be spent somewhere else.

Oh.... with all the extra spring pressure you need for the roller lifters, it's really hard on camshaft bearings. Forgot to mention that little tid bit.

I agree, you need to visit more often!

_________________
Hyper_pak

Thanks a bunch for the real-world experiences, Dave. I was hoping you would chime in.

Lou

_________________
Home of Slant6-powered fun machines

I still think a mushroom tappet setup might be a viable option for a slant. I only wish I had the time to do a "proof of concept". I did purchase a couple of different lifters just to see if it would be feasible to adapt them into the slant. Looked at both a VW beetle, and Ford "Y" block tappets. Sleeve the lifter bores, counter bore the bottom of the lifter bore, and have Oregon cams grind a cam. Would have to speak to them to see if they could do a correct pattern on a "normal" core.

_________________
Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

I wonder like you about the mushrooms.
But weren't they a little before the roller cams starting taking hold?
Why did they fall out of favor?

_________________
Hyper_pak

Probably the biggest reason was they have to go in through the bottom.

Rollers provided all the benefits at twice the cost.

_________________
Official Cookie and Mater Tormentor.

Mushroom tappets become popular in the 1970's in NASCAR and then trickled down to other genres. Roller cams have been around since the late 1950's. As Slantzilla said, the biggest draw back to mushroom tappets is they have to be installed from the bottom of the block....with the block turned upside down, making cam swaps impossible without pulling the engine....!

_________________
There's no such thing as too much cam....only not enough engine!

Does anyone know how to properly design (or find/copy) a mushroom-tappet cam? I guess you can just use a cast blank, but do the lobes need to be bigger (base circle)?

About 28 yrs ago, I was given a set of 12 brass bushings to press into a Slant block to allow use of VW mushroom lifters. Still in my toolbox, IIRC. Might be crazy enough to try it...

Lou

_________________
Home of Slant6-powered fun machines

Lou, the lobe profile specs are specific to a mushroom tappet cam vs. a regular flat tappet. Many cam companies have them in their lobe library, so it shouldn't be difficult to get their recommendations to suit your needs. Making a cutter for the bottoms of the lifter bores will be a challenge for some, but don't forget to add that to the equation...

_________________
There's no such thing as too much cam....only not enough engine!

Understood.
But what about a roller used with a peanut head.
How do remove those lifters?

_________________
Hyper_pak

Roller lifters are inserted into the lifter bores the same way a flat tappet hydraulic or solid lift lifter is, from the top side of the engine. To remove them you simple lift them upwards out of the bore from the cylinder head side of the block....

What made the mushroom tappets obsolete was quickly advancing cam profile technology and being able to grind cam profiles on a traditional flat tappet lifter platform that exceeded what a mushroom lifter could benefit over them previously. Plus, the simplicity of removing the lifter in the conventional manner made the mushroom tappet fade away....

_________________
There's no such thing as too much cam....only not enough engine!

What type of cut is needed on the bottom?

_________________
2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Since the base diameter of the mushroom lifters are larger than the lifter bores, you have to spot face a counter bore on the bottom side of the lifter bore to allow the mushroom portion of the lifter to have clearance on it's most upward part of its travel so it(the mushroom portion)doesn't hit the block in the cam tunnel. So its basically a recess for travel clearance....but necessary!

_________________
There's no such thing as too much cam....only not enough engine!

If I am not mistaken, the reason mushroom tappets/cams became popular, was racing association rules that said "flat tappet cams/lifters only, no roller cams". The mushroom setups allowed more aggressive profiles then the smaller dia lifters. and still met the letter of the rules.

_________________
Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

The first of next week I'll call Kent at OC and get his input on using the mushroom type lifter on our slant six engines.