Cams: solid flat tappet vs. hydro roller?

[Excaliber]

Solid roller lifter with less than 8,000 miles on it is what led to my "Engine Build Blog" thread when it let go! Darn lucky it didn't take out the rest of the engine with it.

Hydro rollers are better, from what I hear. But I went back to a flat tappet and am VERY happy with the engine over all (and over haul).

[AmericanPie]

Originally posted by FUNFER2


I agree with the solids. I've had no problems with mine. 600 lift-252 duration. Roller Earson rockers. Adjusting the valves take's less than a hour, from removing the valve covers, adjusting the valves & buttoning it all up again. Things like, using all studs, rubber gaskets & the valve lash tools, help in a faster job. After the engine build, I lashed them twice. Since then, only twice per year. With a flat tappet, you can hear & feel when they get loose. I'm happy with my set-up anyway.

Kevin,

Can you give me some more info on your cam? Brand? Part #? It sounds like a nice hot street grind.

Larry

[FUNFER2]

I sure will. I'll e-mail the specs.

[Keithc8]

This is a very much talked about subject. The camshaft choice depends on what will be done with the engine. Two things kill the solid roller lifter bearings, to much spring pressure and lack of oiling at a idle. The solid roller technology has come a long way since a few years ago with force fed roller lifters oiling the roller bearing and this is helping longivity. When choosen a solid roller camshaft you need to know the use street or strip, this makes all the difference in the choice of lobes and and spring pressure. The hydraulic camshaft are only used when the engine does not need to turn over 6300 to 6400rpms and there are a lot of the FE engines that guys do not want to turn higher than this and we are getting 650HP out of them by this rpm. The hydraulic flat-tappet and the hydraulic roller both suffer from this problem and it is due to the hydraulic lifter not being able to stay pumped up. The more you lighten the valve train and the thicker the oil and the higher the oil pressure the more rpms you will get out of a hydraulic camshaft. We have some hydraulic roller FEs that will turn 7200rpms but they have titanium valves and retainers. The solid flat tappet works well for rpm amd longevity but it has some draw backs as well. You need to break most solid flat-tappets in with lower spring pressure to let the lifter rotate and break the camshaft in. Once the camshaft is broke in you then add more spring pressure because with out enough spring pressure the valve will float and break. There are mild solid flat-tappet camshaft as well as aggressive lobes. The more aggresive the lobe the harder to break in and more likely to were out in the future. We have alot of cars come in with solid flat-tappets that have the lobes wore of because the builder did not break the camshaft in or installed to much spring pressure.
The question is much more complicated than which is the best? Which is the best for me and what am I willing to do for the extra power? Your engine builder needs to know your needs and power you want to make. The new solid roller stuff with the right lobes and springs will go 15,000 to 20,000 miles. You also have to remember the guys at the cam companys do not know much about a FE engine and the new blocks that are out that oil throught the lifter galleys as most old blocks do except for most of the 427 blocks that were not drilled through the lifter galleys. Know what you want from your engine and then decide on the camshaft but make sure you have the right lifter, spring pressure, rocker system and pushrods.
We have been using the ceramic lifters in the NHRA stock eliminator and circle track engines for about 10 years now. We can run 200 seat and 450 lbs open pressure with them. We do this so we can turn the engines 8000 to 8500rpms with stainless valves and higher with titanium. Hope this helps a little on the camshaft issues. Thanks, Keith Craft

[RICK LAKE]

Keithc8 Keith I talk to 3 valve companys about running titanium valves on the street , this is without coatings and they all say that the heat cycles kill the valves. I got 1 tech who said he has been running them in his everyday drive and had 10k without any problem. There is always one. Oiling of the rollers seems to be the killer on roller lifters, I am thinking of grooving the lifter bores so the oil runs down the lifter and hits the wheel area. They do this on SBC motors. Start with a .010 groove and see what happens. A single plane manifold with a plastic center will let you look inside the galley with the motor idling and watch the motor oiling. The other idea is a sprayer system to put oil on the cam shaft. I have been trying Lucas oil in my truck motor and let it sit for weeks. I start it up after 2 weeks and the motor is quiet without rocker noise for the first couple of seconds until oil pressure builds up. Climbing or clinging oil may be an answer to helping the problem. Have you tryed a set of beehive springs on one of your motors yet? Thanks Keith. Are you going to enter in the engine masters challenge?? Rick Lake

[Ant]

Keithc8,

Going from your post on Ceramic lifters used with circle track engines for 10years, would they be an advantage for wear compared to other lifters, I dare say the camshaft still wears but the lifter stays convex?

With the Shelby aluminium blocks and the Priority oiling system, has the camshaft lifter oiling situation been improved?

[Keithc8]

I have used a set of the BeeHive springs on one of the nice FE engines we just finished and they seemed to help a little with the rpms. This piticular engine had a hydraulic roller camshaft and did not fall of much up to 6500rpms and at that point I did not know if it was the lifters or the dual plane intake manifold. The springs we use were some of the NASCAR springs that Comp does not make any more.
We have seen no real wear on the camshaft with the ceramic lifters because they stay turning all the time without any hurting the camshaft.
I have used the Titanium valves on very few of the street engines but the ones I have used them in seem to be doing fine. We use them all the time in the Dirt Late Model engines we build
and we will put about 1000 miles of hard racing on them with a lot of heat cycles without any problems yet. If I was going for anything above 20,000 miles I would look at the stainless.
The other thing that is nice about the ceramic lifters is that we can change camshaft as much as we want and re-use the lifters and do not have to break in the camshaft. You do have to watch floating the lifter as they will shatter and make a mess. Thanks, Keith