Valve lifters…solid/hydraulic/roller tappet/flat tappet?

[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

[blykins]

In a SBF, the difference between a flat tappet and a roller cam is just a few hundred bucks. It's well worth it to dodge any break-in issues.

My criteria for choosing which cam is pretty simple:

If you plan to stay under 6000-6200, then a hydraulic roller will fit the bill quite nicely.

If you plan to spin the engine up over 6500-7000, then a solid roller is easier to deal with. The caveat to the solid roller cams is that you have to run high spring pressures. The lifters take a pounding from valve lash, so they will need to be monitored in 7500-10000 mile increments.

For most street engines, the hydraulic roller is the way to go. No break-in, no worries, no maintenance.

[xb-60]

Thanks Brent. So when you say the lifters take a pounding, that's only if the clearances aren't maintained to correct limits? If clearances are correct, and 7500 - 10000 mile intervals isn't a deal-breaker, then no other down side?
What precentage of motors do you build that have solid roller lifters?
Cheers,
Glen

[blykins]

Originally Posted by xb-60

Thanks Brent. So when you say the lifters take a pounding, that's only if the clearances aren't maintained to correct limits? If clearances are correct, and 7500 - 10000 mile intervals isn't a deal-breaker, then no other down side?
What precentage of motors do you build that have solid roller lifters?
Cheers,
Glen

No, they take a pounding just by nature. With a hydraulic lifter, there's lifter preload. The lifter is in constant contact with the lobe and the hydraulic internals absorb a lot of the action. With a solid lifter, there's valve lash, which is extra clearance between parts. If a high quality solid roller lifter was in constant contact with the lobe, it would probably last an extremely long time. However, with valve lash and no hydraulics to dampen the system, the "slop" in the valvetrain exposes the lifter bearings to a "shock" load when it re-contacts the lobe.

I'd say about 30% of my engines are solid roller engines.

[RICK LAKE]

xb-60 Glen Look at this from another side, what are you doing with the car?? shows, racing, autocross, roadcourse, or just street driver. Here are a couple of questions that will deceide what valve train to use also
Rpm limit and range of motor?
Motor size?
Amount of work done to heads and compression of motor
A BIGGIE Exhaust system, under car, side pipes,(street or race pipes) size of pipes?
Trans mission, how many gears, rearend ratio?
Top speed you like in your comfort zone?
Answer these question and we can come up with a good setup for the application.

there are plusses and minusses with running each valve train you have listed. I think most goods and bads are there. IMO a complete roller valve train is the first step. Matching the rest of the parts to this is important for power, sound,duribility, and even gas mileage too. I run a hydro setup for 6 years and race. No problems after getting Erson rockers. Limit of motor is 6,200 rpm with hydro crane roller lifters. A also run Beehive springs going on 12 years without any failures from BBC motors. I build torque motors not high RPM HP motors. 2 thing that are a no-no with a solid setup are idling the motor for any period of time and not check valve lash and keeping note on which ones needed adjustment. Fill in the questions and see where we go with parts and setup. Rick L. ps look at some of the buildup of your motor size for other ideas. DON'T get glassy eye with some of these dyno sheet in the rag/mags. They get a little over the top with numbers. Rick L.

[LightNFast]

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[xb-60]

Originally Posted by RICK LAKE

xb-60 Glen Look at this from another side, what are you doing with the car?? shows, racing, autocross, roadcourse, or just street driver. Here are a couple of questions that will deceide what valve train to use also
Rpm limit and range of motor?
Motor size?
Amount of work done to heads and compression of motor
A BIGGIE Exhaust system, under car, side pipes,(street or race pipes) size of pipes?
Trans mission, how many gears, rearend ratio?
Top speed you like in your comfort zone?
Answer these question and we can come up with a good setup for the application.

there are plusses and minusses with running each valve train you have listed. I think most goods and bads are there. IMO a complete roller valve train is the first step. Matching the rest of the parts to this is important for power, sound,duribility, and even gas mileage too. I run a hydro setup for 6 years and race. No problems after getting Erson rockers. Limit of motor is 6,200 rpm with hydro crane roller lifters. A also run Beehive springs going on 12 years without any failures from BBC motors. I build torque motors not high RPM HP motors. 2 thing that are a no-no with a solid setup are idling the motor for any period of time and not check valve lash and keeping note on which ones needed adjustment. Fill in the questions and see where we go with parts and setup. Rick L. ps look at some of the buildup of your motor size for other ideas. DON'T get glassy eye with some of these dyno sheet in the rag/mags. They get a little over the top with numbers. Rick L.

The car doesn’t exist yet, and the engine doesn’t exist yet…..but it definitely will eventually. So, I’m in the planning / gathering information / theorizing / gathering bits stage, with folders filling with information. One of the larger ‘bits’ is the engine, hence the question about things like lifters.

Here are my thoughts about what I want in an engine, and these are idealistic:

Vintage appearance 302, with stock capacity except for cleanup overbore
Intended use is street
RPM range is 2000 to 7000. I want reasonable (but not stump-pulling) torque at the lower end to suit my preferred diff ratio, and that free-revving feeling at the top end. Target power and torque figures aren’t that important, as the power-to-weight will be good, no matter what the power is.
Heads would preferably be CI for authenticity, but I’m also persuadable towards alloy heads.
Exhaust will need cats, will be undercar but both pipes exiting ahead of rear wheel on driver’s side; pipes sized to suit engine, not eye.
Gearbox will be a WR Toploader
Diff ratio will be 3.07:1
Top speed? Not important.
Reasonable cost
Fuel consumption not excessive, however this is low down the list as annual mileage will be low.
I should also add that emissions tuneability may, or may not, be an issue. Let’s say at this stage it’s not an issue.
Webers, as this is a wish list.

Thanks for your interest,
Cheers,
Glen

[Gaz64]

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

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.

[blykins]

Yes, and I would watch about spinning the engine to 8000 rpm. How the engine was balanced would be the least of my concerns there.

[CHANMADD]

The motor that I built can live...believe me at 8000rpm all day long.I have built a lot of race motors in my time. The bottom end determines whether or not the motor is going to live at high rpm or not, and the balancing is extrememly important when a motor is expected to live at high revs. Besides having the correct crank and rods, the pistons and all the reciprocating components all need to be correctly weighted to each other...the balance does not simply mean that the crank spins without a vibration. The complete package ,like cc'ing the heads, combustion chambers and ports, not that they just look nice ,but they all need to be exactly the same.
Most all the builders I see here are new to this and do not grasp all that is involved in making an engine live at all rpm's. Most seek highest horse power to put in these little cars that is actually overkill completely.Like expensive ignition systems that do nothing extra above idle..????.
I have taken apart many "Proffessionally Built" engines that don't perform right because they were not properly balanced/blueprinted, even to the point of cracking bell housings, that are blamed on everything else. Overkill is not always the correct answer.
Likewise I do not like to run to much tire , so as not to strain the driveline....I would rather spin the tires than break a sideshaft or driveshaft......which I have seen more than once,and inevitably leaves one on the side of the road.

[blykins]

So what kind of engine is it, and what parts did you use?

[ERA Chas]

Originally Posted by blykins

So what kind of engine is it, and what parts did you use?

According to his gallery, an SBC. Do you know of a rev kit made for SBF Brent?

[CHANMADD]

By the way I too am a Mechanical Engineer.

[CHANMADD]

Rev Kits
Here is one I found real quick

[ERA Chas]

Originally Posted by CHANMADD

Rev Kits
Here is one I found real quick

Thank you Chan but I should have made my question more specific. The OP is planning an 8.7 deck and this particular kit is for the 9.5. I've not seen a kit for 8.7.

[CHANMADD]

I am sure it would just require a different spring, ....should'nt be too hard to find. The same manufacturer would probably be able to supply it.

[blykins]

I haven't seen any.

The reason is probably because it's such a tight fit on a 302 block. You can't even pull roller lifters out without jerking the heads off first.

You'll see different opinions about rev kits as a lot of builders don't use them. What is important for a high revving solid roller is adequate spring pressure and I start using stud girdles or shaft rockers starting around the 7000-7500 mark. Spinning an engine to 8000 rpm takes more than what most people realize. Making power at 8000 takes a LOT more head and cam than what most people realize as well.

I wouldn't recommend a solid roller for the OP. I think it would be more expense and maintenance than necessary for what he's looking to do.

[ERA Chas]

Originally Posted by blykins

I haven't seen any.

Making power at 8000 takes a LOT more head and cam than what most people realize as well.

Thanks Brent-didn't think so. I think Olsen and Rem would have used them in the day for Dragon Snakes or rr cars if available.

Yes and even the OP's desire for 7000+ with power would be much better served with modern AFR's or similar with shafts or stud girdles and stiff springs-not a rev kit. And certainly not iron heads unless Brzezinski has a killer head design.

Since he said top speed unimportant, at least a 3.54:1 or steeper would give him the zing he wants with such a combo.

[CHANMADD]

I agree ,for most purposes a nice hydaulic roller cam in a 302 is more than adequate.Like I said 350 hp in a Cobra is plentyfor most applications.

[blykins]

350 is plenty, 600 is perfect.