TIMSPEED

Does SOLID roller, mean the block is entirely a roller motor? Ie: Hydraulic Roller Cam, Hydraulic Roller Lifters, Roller-tip Rocker Arms? I've always wondered if that's what it meant.

Nathan Plemons

It refers to the lifter only. A hydraulic lifter can self adjust somewhat and not require the frequent adjustment that a mechanical lifter does. A roller lifter allows for far less camshaft and lifter wear, however they still need to be adjusted on a regular basis. A hydraulic roller lifter is kinda the best of both worlds, low wear and no real need for adjustment, they do have their downfalls however. A hydraulic lifter can only bleed down so fast, else it will "pump up" and your valves won't close all the way in the high RPM's. This robs horsepower and can possibly cause damage. I'm only guessing here, but I think a very good set of hydraulic rollers would be about at it's operating limit as you approach 7k RPMs.

A solid roller lifter is your best performance bet, it can handle almost any of the RPM's you want to throw at it, but again they have to be adjusted frequently.


Help at all?

TIMSPEED

YES! :D I get it now, a SOLID ROLLER = type of lifter. ok ok ok.

Smitty's75

Actually it refers to the cam grind that requires a solid roller lifter,,,ie you can't put solid lifters on a hydraulic cam and visa versa,,it a solid roller cam or a hydraulic roller cam.

JAKE

Good question. Wow, this could take some explaining. Sometimes the things many of us take for granted can be really complex to explain, but I'll try.

SOLID roller simply means the engine has a roller camshaft that has been ground for and has mechanical roller lifters which will need period adjustment to the lash. Lash is the clearance between the valve stem tip and the rocker arm when the lifter is on the base circle of the cam.

Base circle is that area when the lifter is not rising or falling. Picture an egg; the end of the egg OPPOSITE the pointed end is the place we call the base circle.

Solid roller doesn't have anything to do with the rocker arms and there are NO hydraulic components involved. It deals only with the cam and lifters.

Here's the deal as I see it.

There are four basic families of lifters.

Flat tappet hydraulic
Flat tappet mechanical (solid)
Hydraulic roller
Mechanical Roller (solid)
Some engines don't have lifters at all, but we won't get into that.

Now the differences:

Each kind of lifter has to be matched to a specific, matching type of camshaft and vice versa. There are a very few exceptions, but it's best to always check with the cam maker if you want to consider changing.

In other words, there are a few types of camshaft profiles ground for mechanical lifter cams that can you use a hydraulic lifter on, but these are the exception rather than the rule.

So what's the deal? The ramps on the camshaft lobe dictate which type of lifter is called for. Lifters for hydraulic flat tappet cams are different from the same cam with the same specs but that has been ground for mechanical (solid) lifters.

Mechanical cams/lifters are the type that must be periodically adjusted.
Hydraulic cams/lifters are the type that has internal valving that automatically adjusts and they do not require periodic adjustment.

Almost all cams that come in engines from the factory in today's engines are hydraulic, either flat tappet or roller. Back in the 60's, some engines came with mechanical flat tappet cams and lifters, but not many come that way any more. Maybe some imports, etc.

Flat tappet lifters are just that, flat on the bottom. Well, not exactly flat but compared to roller lifters - which have a needle bearing roller on the bottom - it's easy to tell the difference.

There are power differences among the different types of cams/lifters, but you didn't ask about that so I'll shut up now.

Hope this helps.

Jake





[Modified by JAKE, 6:14 PM 3/22/2002]

red-y

Jake - Thanks for the detailed response - even though it was not my question.
Nice to see the details.. :cheers:

TIMSPEED

Yes, thanks for clearing that up..now when I talk amongst my friends, I won't look like a fool.

CFI-EFI

Well done, Jake.

MSR

autoxer, fyi, some grinders have dual-role lobes, now. these are cams that will run as tight-lash solid rollers (.010" hot clearance), or hydraulic rollers. just change lifters/springs depending on which you want.

results are pretty good, too. i know of a 396 lt-1 vette that made 475rw with one of those.