Cam/lifter life - flat vs roller?

[J.Jensen]

Is there a big difference between cam and lifter life in flat vs roller lifter setups?

With flats requiring a break-in period and maybe even the heads coming apart to change springs after break-in, and rollers being able to run steeper lobe angles - I can't see any reason to build a new engine with a flat tappet cam except saving a little on cam and lifters?

[PSB]

The only reason I can see for using flat tappets is if you have an older block and don't want to mess with a roller lifter retrofit. There are plenty of options to retrofit an old block, but it does add cost.

[750hp]

Hydraulic rollers are the best combination of power and reliability. Solid rollers can run even more aggressive profiles to make more power on the right engine, but then the downside is lifter life (and the nagging thought that one of them will fail and leave a trail of destruction inside your engine).

A properly run in flat tappet camshaft (solid or hydraulic) will last almost for ever.

Of the 4 options of solid/hydraulic and flat/roller, the only one with a shortened service life is the solid roller.

[J.Jensen]

Why does a solid roller have shorter service life than a hydraulic roller - and what is short? 1000 miles? 10000 miles? Highly dependent on use and spring rates?

The rolling part of the lifter in contact with the cam is the same for both is it not?

[blykins]

Solid roller cams have lash and generally higher spring pressures. Those two combined don't make it a fun scenario for a lifter.

Hydraulic roller cams will generally go 100000+ miles. Solid roller lifter life is somewhat reduced, and that reduction is also based on the quality of the lifter.

[Hotfingrs]

For my money, if you're going to use a solid roller, then Crower lifters are the only way to go. I ruined two engines using other well known brands, and spent quite a bit of time on the phone talking to manufactures before going with Crower. Current engine has been in the car for six years, plenty of 8000 rpm+ shifts, .740 lift on cam, and 200 lbs+ closed and 600 lbs+ open and never a problem. Driving around 1500 miles a year, while the other lifters didn't make 800 miles with the same specs.

[blykins]

Crower is good, but I also trust Morel and Isky. For street solid rollers that will see a lot of driving, I use nothing but bushed lifters.

[lippy]

Originally Posted by Hotfingrs

I ruined two engines using other well known brands, and spent quite a bit of time on the phone talking to manufactures before going with Crower.

Which lifters failed? I'm assuming they used needle bearings. Some details on the build and failures could be really helpful. Thanks.

[J.Jensen]

Can one safely do 10-15k miles on a good set($1000?) of solid rollers with regular lash check?

[Hotfingrs]

Lippy,

Same specs as posted. Comp Cams was the first lifter that failed. Broke the roller off of two lifters and when I pulled the engine there was another five lifters without any bearings left in the rollers. After calling Comp Cams and telling them that I got less than 1000 miles on their lifters, their response was.... that's great, those lifters are only supposed to last 800 miles and the springs 1000 miles. Every manufacturer that I talked to told me I couldn't run those spring pressures on the street. When I talked to Crower they asked me if I was happy with the springs I was running, and I said yes. They said keep using them because you won't have any problems with our lifters. I've been using them for the last 10 or 11 years now.

[blykins]

Originally Posted by J.Jensen

Can one safely do 10-15k miles on a good set($1000?) of solid rollers with regular lash check?

Yes, and then some.

[J.Jensen]

Would you recommend a solid roller for a hp peak around 6500 but with the option to pull a little further if you run out of gear on the straight?

[blykins]

What engine platform?

[J.Jensen]

8.2" sb with webers and a suitable head selection for the cam you´d select.

[blykins]

You could hit 6500 and a little over with a hydraulic roller in a SBF with some careful parts selection. FE's are a little more unforgiving in that respect.

I just dyno'd a 347 that made peak hp at 6000, but wouldn't float the valves until about 6700-6800.

[olddog]

I'm just a guy who reads and fantasizes about engines. I did build a few many years ago, but an expert I am not. That said I have an opinion.

Flow through the engine is what makes power. The heads, intake, exhaust is where most of the flow comes from. The better these components are the less aggressive the cam profile needs to be. I would put my money in the heads and intake to get the power I wanted, and stay with a nice hydraulic roller that lasts and lasts and does not have to have the valves adjusted all the time.

To me a solid roller cam is for an engine that is raced and needs every last fraction of power. These engines get pulled down frequently and checked, so longevity is not an issue.

They can be ran on the street, but why go to all this trouble when it just isn't necessary? On the street, who can tell the difference between 500 hp and 550 hp by the seat of their pants?

[CHANMADD]

Well.......If one reads how most guys use and drive their cars..most would be happy with ..300hp and a hydraulic cam. There was a "how fast have you had your car" thread , and very few have even been over 100mph.

[601HP]

Originally Posted by olddog

I'm just a guy who reads and fantasizes about engines. I did build a few many years ago, but an expert I am not. That said I have an opinion.

Flow through the engine is what makes power. The heads, intake, exhaust is where most of the flow comes from. The better these components are the less aggressive the cam profile needs to be. I would put my money in the heads and intake to get the power I wanted, and stay with a nice hydraulic roller that lasts and lasts and does not have to have the valves adjusted all the time.

To me a solid roller cam is for an engine that is raced and needs every last fraction of power. These engines get pulled down frequently and checked, so longevity is not an issue.

They can be ran on the street, but why go to all this trouble when it just isn't necessary? On the street, who can tell the difference between 500 hp and 550 hp by the seat of their pants?

I like your summary olddog. If I had built and driven in like manner, I'd have gone into my engine far fewer times and tossed less $'s toward it. But......I switched to a solid roller cam about 15 years ago. I like pushing this car's engine toward its limits. I kinda look forward to the occasional under valve cover inspections and adjustments.

In contrast, my daily driver is a Toyots Yaris. Its a predictable little car that requires minimum attention. I rarely see the tach above 3,000 rpm.

David

[xb-60]

What about an update on that 347 Brent? It's been over a month. Is it finished?
Cheers,
Glen

[blykins]

Which 347? The one on page 1 of this thread? It was dyno'd and delivered a long time ago.