Solid Roller vs. Hyd. Roller - Pros/Cons?

[RodKnock]

Well, I honestly don't have the time nor inclination to respond Brent or Barry and will yield the floor to their vast experience and expertise in this matter.

[Barry_R]

Actually at 1.27/cube your torque number seems pretty rational for a strong build, although your power peak RPM seems low compared to the torque peak. I usually see +/-1500 RPM between them - your's is a comparatively narrow 1000 - you might have more "in the bank" if you can find out why it stopped there. Or you may have something in the combination stunting the lower RPM torque or forcing the curve upward. I sometimes see really brutal torque "bumps" from IR setups when they hit the resonant tuning length.

I have, however, seen some FE dyno data posted around the net with torque at 1.5 or 1.6 per cube and that simply ain't right. It might happen in a Super Stock or dead serious race package with tons of compression and cam - but not in the land of pump premium and hydraulic rollers.

[Dimis]

Thanks to all who have PMed and responded.
It was greatly appreciated.

FWIW:
After some deliberation and research, I've ended up opting for solid rollers.
Why? Here's my logic:

1. The "professionals" prefer them for their builds.
a) KC used them for his personal Kirkham
Finish my engine for Kirkham
b) Barry uses them in his grocery shopping Torino (as per earlier in this thread Post #55 & #60).
c) last but not least - Brent mentioned he prefers them for his builds, and particularly recommends them for non daily drivers.

2. It suits my combination of parts better.
Accordong to Jay Browns book the TW was still pulling when most others had maxed out.
The Hydraulic rollers will quit just as the tunnel wedge would wake up.
To paraphrase Blair Patrick from Fordfe - "it's all about the combo combo combo."

3. Power and RELIABILITY will still be there!
The only thing that's changed is the cost.
...and while it will cost a little more, it is a better principle to over engineer this, than to skimp or compromise and risk valves kissing pistons. In the big scheme of things though the cost is not excessively more, and IMHO worth doing.

4. Despite peak numbers being higher drive-ability should remain the same
...particularly in the "range" that I mostly intend to use it.
I conclude this by attributing the extra HP to the extra Rpm.
Driving below 4k the engine should more or less drive much the same.
There just won't 50hp difference at 1/4 throttle, particularly if the car is cammed relatively the same.
The cubic inches doesn't just increase the max power numbers, if I understand it right, that's just a bi-product of allowing the engine to behave more respectably at low rpm with the same sized cam.


Now if there are flaws in my logic... Meh...
You live and learn, and so far this is what I've learned.

Thx again.

[RodKnock]

Dimis, sounds like a very well-researched and intelligent choice. Congrats and we look forward to hearing your Cobra alive and breathing.

[lippy]

Originally Posted by Dimis

Thanks to all who have PMed and responded.
It was greatly appreciated.

FWIW:
After some deliberation and research, I've ended up opting for solid rollers.
Why? Here's my logic:

1. The "professionals" prefer them for their builds.
a) KC used them for his personal Kirkham
Finish my engine for Kirkham
b) Barry uses them in his grocery shopping Torino (as per earlier in this thread Post #55 & #60).
c) last but not least - Brent mentioned he prefers them for his builds, and particularly recommends them for non daily drivers.

2. It suits my combination of parts better.
Accordong to Jay Browns book the TW was still pulling when most others had maxed out.
The Hydraulic rollers will quit just as the tunnel wedge would wake up.
To paraphrase Blair Patrick from Fordfe - "it's all about the combo combo combo."

3. Power and RELIABILITY will still be there!
The only thing that's changed is the cost.
...and while it will cost a little more, it is a better principle to over engineer this, than to skimp or compromise and risk valves kissing pistons. In the big scheme of things though the cost is not excessively more, and IMHO worth doing.

4. Despite peak numbers being higher drive-ability should remain the same
...particularly in the "range" that I mostly intend to use it.
I conclude this by attributing the extra HP to the extra Rpm.
Driving below 4k the engine should more or less drive much the same.
There just won't 50hp difference at 1/4 throttle, particularly if the car is cammed relatively the same.
The cubic inches doesn't just increase the max power numbers, if I understand it right, that's just a bi-product of allowing the engine to behave more respectably at low rpm with the same sized cam.


Now if there are flaws in my logic... Meh...
You live and learn, and so far this is what I've learned.

Thx again.

Dimis,

I chose solid rollers for largely the same reasons, with the addition of (1) the sound of a solid roller engine is different, and incredible, and (2) from my limited experience but Brent's extensive experience, the power delivery for a solid roller engine feels different and comes on stronger at mid-RPM, sort of like a roller coaster.

BTW, I don't care that much about the dyno numbers per se. I know they can vary. But the combination of parts in this build, and Brent's care and attention to detail, definitely will yield great results. I'm very happy with my experience with Brent and I'm looking forward to providing some real feedback on this build once I get the engine on the road (dropping it in this weekend!)

-Lippy

[Dimis]

Lippy, Truth is I only went solid rollers cos I was jealous of yours.
That's just how shallow I am.

And I told Brent I want 2 carbs so that mine could be better than yours
And that I wont be paying him a cent unless it has at least 639hp which is one more that yours because it really really really matters

Now if people reading, believe that ^ There's NO saving them


In all serious - Your build certainly did help pave the way for me.
I'm grateful you allowed Brent to post it.

I'm also grateful for Brent's time, energy and guidance through the whole process. The experience with this build has been that good, that I'm somewhat melancholy it's nearing an end.

[1795]

Dimis,

Just be careful as you get used to the car. When both of those four barrels kick in it is a lot of torque! Mine breaks loose pretty easy with all of that power. Nice to see another FE with dual quads.

Jim

[patrickt]

Jim's advice is sound. I have a hundred horsepower less and, last summer, when I was installing the adjustable vacuum secondary gizmo I had trouble on the street getting my secondaries to open fully because the rear wheels were spinning loose. I've been driving that car going on eight years and it's almost second nature to me... but the very few times that I go heavy on the throttle is still scary. And wheel spin at any speed over, say, 40 MPH, on the street is not only stupid, it's potentially dangerous as well. Just remember that if you're revving 3500 RPM in, say, 3rd gear, and for some reason you just decide to floor it, you have a 50/50 chance of wrecking your car.

EDIT - This is the gizmo of which I speak: Theoretical Vacuum Secondary Question

[RodKnock]

Originally Posted by Dimis

Lippy, Truth is I only went solid rollers cos I was jealous of yours. That's just how shallow I am.

And I told Brent I want 2 carbs so that mine could be better than yours
And that I wont be paying him a cent unless it has at least 639hp which is one more that yours because it really really really matters

But we all pale in comparison to rodneym's twin Paxton FE and that Cammer build Keith just posted.

Makes my 500 HP 482 (maybe even less depending on the dyno) look like something the dog just pooped on the lawn.

(just kidding)

[blykins]

Originally Posted by Dimis

Thanks to all who have PMed and responded.
It was greatly appreciated.

FWIW:
After some deliberation and research, I've ended up opting for solid rollers.
Why? Here's my logic:

1. The "professionals" prefer them for their builds.
a) KC used them for his personal Kirkham
Finish my engine for Kirkham
b) Barry uses them in his grocery shopping Torino (as per earlier in this thread Post #55 & #60).
c) last but not least - Brent mentioned he prefers them for his builds, and particularly recommends them for non daily drivers.

2. It suits my combination of parts better.
Accordong to Jay Browns book the TW was still pulling when most others had maxed out.
The Hydraulic rollers will quit just as the tunnel wedge would wake up.
To paraphrase Blair Patrick from Fordfe - "it's all about the combo combo combo."

3. Power and RELIABILITY will still be there!
The only thing that's changed is the cost.
...and while it will cost a little more, it is a better principle to over engineer this, than to skimp or compromise and risk valves kissing pistons. In the big scheme of things though the cost is not excessively more, and IMHO worth doing.

4. Despite peak numbers being higher drive-ability should remain the same
...particularly in the "range" that I mostly intend to use it.
I conclude this by attributing the extra HP to the extra Rpm.
Driving below 4k the engine should more or less drive much the same.
There just won't 50hp difference at 1/4 throttle, particularly if the car is cammed relatively the same.
The cubic inches doesn't just increase the max power numbers, if I understand it right, that's just a bi-product of allowing the engine to behave more respectably at low rpm with the same sized cam.


Now if there are flaws in my logic... Meh...
You live and learn, and so far this is what I've learned.

Thx again.

Drive-ability will change a little. When you move the power band up, you take away from the bottom end and incidentally it will make idle and off-idle performance a little "soggier". If it were a 4000 lb Galaxie with a 3.00 rearend, it would be one thing, but a 2400 lb Cobra is another. You also have cubic inches in your favor. The cubes help "dumb down" a single plane intake and will generate a broader curve in and of itself...in comparison to a smaller displacement engine.

If you would compare a dyno sheet between the engine that you originally spec'd and the way we're going now, you'll see the curves move toward the right, which makes less horsepower available towards the left. Again, not that it matters....when there's an ample amount available everywhere.

All-in-all, this is what I call "riding the fence". There are tow truck engines, then there are race engines (high compression, higher rpms, etc.) and then there are engines that ride the fence. It can get very tedious as you focus on the intimate details, and since every guy has his preference on behavior, an engine builder has to "feel them out" and see exactly which way to go. It's tricky sometimes.

[fordracing65]

Originally Posted by blykins

Drive-ability will change a little. When you move the power band up, you take away from the bottom end and incidentally it will make idle and off-idle performance a little "soggier". If it were a 4000 lb Galaxie with a 3.00 rearend, it would be one thing, but a 2400 lb Cobra is another. You also have cubic inches in your favor. The cubes help "dumb down" a single plane intake and will generate a broader curve in and of itself...in comparison to a smaller displacement engine.

If you would compare a dyno sheet between the engine that you originally spec'd and the way we're going now, you'll see the curves move toward the right, which makes less horsepower available towards the left. Again, not that it matters....when there's an ample amount available everywhere.

All-in-all, this is what I call "riding the fence". There are tow truck engines, then there are race engines (high compression, higher rpms, etc.) and then there are engines that ride the fence. It can get very tedious as you focus on the intimate details, and since every guy has his preference on behavior, an engine builder has to "feel them out" and see exactly which way to go. It's tricky sometimes.

But that's why your the best at it...

[Danr55]

Hey Rod knock, please send your dog to my yard!