I can’t wait to read the before and after results of a roller cam.
I'm getting close to switching to a roller cam in the big block!
- Thread starter Kern Dog
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Hemirunner
Well-Known Member
Once you go roller, you’ll never go back to a flat tappet. They have their place in low buck builds and restoration engines and such but in a performance engine, roller cam all the way. Sounds like you’re in good hands with this one.
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Since my other engines have held together with the milder cams and springs, (Also with vintage parts) they will stay that way.
THIS car has always had the biggest camshaft, stiffest springs and highest compression of the cars that I have. It is also the one that I drive the most and unfortunately, it has had 3 flat tappet cams go bad out of the 5 that I've used in this block. At a glance you'd think that there is something wrong with the block but you have to consider all the factors. High performance parts are under a lot more stress than 318 parts and that stress can reveal weaknesses that are not usually seen in milder engines. The roller design should alleviate the risks that I've dealt with for years.
THIS car has always had the biggest camshaft, stiffest springs and highest compression of the cars that I have. It is also the one that I drive the most and unfortunately, it has had 3 flat tappet cams go bad out of the 5 that I've used in this block. At a glance you'd think that there is something wrong with the block but you have to consider all the factors. High performance parts are under a lot more stress than 318 parts and that stress can reveal weaknesses that are not usually seen in milder engines. The roller design should alleviate the risks that I've dealt with for years.
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Summit racing has the lifters in stock but since I'm not in a hurry, I'm going to wait until Dwayne Porter can get a set to have sent to me. He has been a friendly and helpful Mopar guy and I want to do right by him.
There are all the other things to buy along the way which as weird as it sounds, the delay helps matters.
It is purely in my head but paying ONCE in a large chunk of money just eats at me. It defies logic to make 5 purchases that still come to the same total but for some reason, I don't feel as bad doing it that way.
Other car guys must have the same mindset too though. We all know (or ARE) the guy that buys an abandoned project cheap and spends about double to get it completed as it would have cost to buy a finished car.
I sometimes feel like in another life, I lived in the Depression where you had to be frugal just to survive.
There are all the other things to buy along the way which as weird as it sounds, the delay helps matters.
It is purely in my head but paying ONCE in a large chunk of money just eats at me. It defies logic to make 5 purchases that still come to the same total but for some reason, I don't feel as bad doing it that way.
Other car guys must have the same mindset too though. We all know (or ARE) the guy that buys an abandoned project cheap and spends about double to get it completed as it would have cost to buy a finished car.
I sometimes feel like in another life, I lived in the Depression where you had to be frugal just to survive.
Hemirunner
Well-Known Member
I’m not sure how you drive this particular vehicle, but we tend to be rough on things in my world. Have you considered putting solid lifters on the hydraulic roller cam and tight lashing it? If it’ll see some spirited high rpm action, it may be food for thought. I’m sure you’ve discussed it all with Porter.
BSB67
Well-Known Member
For clarity, you mean solid roller lifts, correct?
I'll double down and ask what's the advantage over a solid roller cam?
Curiousyellow71
Well-Known Member
This is over simplifying, but roller cam failures happen when a lifters roller bearing gives up. When the rollers bounce it is hard on the needle bearing or bushing. If you run a solid roller lifter on a hr cam which has no lash ramp about the only lash the lifter will see is when the engine grows. So there is less lash. If we set a engine with aluminum heads to 0 cold..it is about .007 hot. Iron headed engine even less. Less lash is less lifter bounce. Hopefully prolonged lifter life more comparable to a hydraulic roller lifter, but with less mass and no hydraulic cushion which is why the hr lifter gives up power at the upper rpms.
The next thing to consider the intensity to .050. Typically a softer open is needed for a hydraulic lifter to work. With a solid roller the softer open is easier on the lifter on the street. You can have a solid roller ground with the same intensity but it will still have the lash ramp. They make roller cams that can be used for hydraulic or solid lifters as well, we run one from Bullet. It's silent. You would never know it has a hybrid roller cam. It's not going to make as much power as a solid roller but hopefully out last it. Downside compared to a Hydraulic lifter is you have to run the some lash as a hybrid still has lash once its hot.
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Greg,
I'm sure you know this but you will most certainly need new pushrods as well - the roller lifters are much taller than the old ones. When you mock everything up, make sure your valvetrain geometry is where it needs to be, then measure and order your pushrods.
I'm sure you know this but you will most certainly need new pushrods as well - the roller lifters are much taller than the old ones. When you mock everything up, make sure your valvetrain geometry is where it needs to be, then measure and order your pushrods.
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