Quote:
Originally Posted by xb-60
Last time I rebuilt an engine, it was a simple solid lifter setup with flat tappets. That was …hmm…a while ago. Things have changed with lifters since then.
So, my questions….
- Is it a no-brainer to go the roller tappet route, or are there circumstances where flat tappets are preferable? I know the cam lobe tip radius is larger on a roller cam, so maximum lift is maintained for longer. I assume cam lobe and lifter wear is less on a roller setup.
- What are the benefits of hydraulic lifters over solid lifters apart from maintenance and arguably noise? (I say ‘arguably’ because I like the noise).
- Conversely, what advantages do solid lifters have over hydraulic lifters.
I need an update to bring me into “C21”
Cheers,
Glen
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Glen,
The roller cam lobe has a larger radius nose, the reason being the lifter only has wheel contact ( a line of contact ), versus the sweep of a flat tappet cam across the base of a flat tappet lifter.
You can certainly get more aggressive lobes with a roller, versus flat tappet ramps limited by tappet diameter.
Solid roller wheels suffer from the pounding of tappet clearance, once the wheels skid and flat spot, it's goodbye to the cam and lifters.
Each has their advantages and disadvantages.
The higher you wish to spin the engine, the more it costs to have adequate parts for the job, the more likely for long term failure, and the more periodic maintenance required.
A roller cam of either tappet type will give a better spread of torque, than a flat tappet cam of comparable duration.
I'd go for a solid roller every time, but if you don't ticker with your own engines, I'd recommend you either pick a mild - warm hydraulic roller or a solid flat tappet as the maximum.