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

[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]

........................

[xb-60]

Originally Posted by LightNFast

Glen,

Shelby’s 289 “High-Rev” Cobra engines were rollers and produced about 390HP @ 7000. So even back in the 60’s they knew it was better to roll…

Kurt,
Yes I’ve read a few old tests where rev limits of 7000 or even higher were mentioned for 289s. These were probably accompanied by grumpiness at lower revs, but that being almost 50 years ago, I’m assuming that developments in cams / heads / carburation / fuel injection has made available better compromises.
One of my other cars is a mid-seventies Alfa twin cam (unmodified) with side draft Webers. This engine has stacks of grunt from not far above idle, and at the 6000 redline, it feels like it wants to keep going forever. My daily driver, an Australian built ‘cooking’ V6, is redlined at 6200, sees the redline at least once a day and loves it. That’s what I want in a 302.
Cheers,
Glen

[zrayr]

Originally Posted by xb-60

Kurt,
Yes I’ve read a few old tests where rev limits of 7000 or even higher were mentioned for 289s. These were probably accompanied by grumpiness at lower revs, but that being almost 50 years ago,........."
Glen

I routinely shift at 6,500 to 7,000 rpm. The engine is an essentially stock 289 Hi-Po K code. It is a flat tappet engine, with a stock Hi-Po cam. There is no grumpiness at any rpm, idles fine at 900 and is smooth to 7,000+ rpm. In a nine year time span I've got over 45,000 miles on the engine. Seems very durable to me. With good lubrication, meaning an oil with plenty of zinc, there are no issues with cam or lifter wear. Been using Mobil 1 15w-50 the entire 9 years.

Z.

[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

[blykins]

We'll have to have a talk.....

There's a familiar saying, "You can't have your cake and eat it too..."

With a small displacement such as a 302, making horsepower at 7000 rpm will pretty much insure that you won't have any power at all at 2000 rpm. The cylinder head and cam necessary to make horsepower that high will knock you out of any low end power. Even with a stroked 302 (331-347), you can definitely make horsepower at 7000, but you won't be making much at all at 2000.

Coupling a very high strung engine with a 3.07 rearend is also not the best route to take. You certainly have weight on your side with a Cobra, but using a 3.07 gear with an engine without a bottom end is like getting on a bicycle and taking off in 10th gear. You will have no power or acceleration whatsoever in the lower rpms and it will really labor the engine.

My advice would be to hit somewhere in the middle. A stroked 302 (331-347 cubic inches) would be the route to take. If your plan to use 3.07 rear gears is definite, then I would choose a cylinder head and cam to take advantage of that. You would need more low end and mid range power with a higher rearend gear. If I were building this engine for you, I would cam the engine so that the horsepower peak would be around 5500-6000, so that you actually would have some power at 2000-2500 where you'll be spending a lot of your driving time.

I may sound like a broken record as I say this on all the forums and in all my magazine articles, but plan the engine around the rpm range that you will be running in the most. There's nothing wrong with wanting horsepower at 6500-7000, but just remember that when you move the horsepower curve to the right, it takes away power from the left. And when you start with a very small engine to begin with, you really cut yourself short.

As for the heads, there are some nice flowing cast iron heads out there, specifically the ones from RHS.

[xb-60]

Thanks Brent. Definitely agreed that the engine needs to be friendly in its main operating rev range. What I do want to avoid though is an engine that really feels like it’s tapering off after say 5500. I want the same eagerness approaching the redline that my other two cars show, so if an engine has that, but a redline of ‘only’ 6200 to 6500, then I could be talked around. When I say ‘eagerness’ at or close to redline, I don’t necessarily mean ‘big power’, I just don’t want it to seem like it’s starting to strangle. That make sense?
Cheers,
Glen