Roller Camshaft Rpm Range

[Slantsix64]

What do you guys think the operating range of this camshaft is?
I run out of steam at 5100 RPMS with my 5.9 ported heads rpm air gap 750 Holley vacuum secondary.

218/224 @ .50 .478 lift 106in 114 ex

 

[273]

The cams rpm is dependent on the combo it's in. You think it would do better than 5100 rpms though, what are you using for valve springs ?

 

[cookietruck]

Is it a stroker motor?

 

[junkyardhero]

The cams rpm is dependent on the combo it's in. You think it would do better than 5100 rpms though, what are you using for valve springs ?

what no graphs or charts?
*tsk tsk*
you're slipping!

 

[273]

what no graphs or charts?
*tsk tsk*
you're slipping!

Here you go a roller in a stock 5.9l headers and 4 bbl

What's wrong with graph's ? pic is supposedly worth a 1000 words

 

[junkyardhero]

pic is supposedly worth a 1000 words

woah, woah buddy. we don't need AJ up in here...

anyway. these might be helpful to OP

(DV's stuff purposefully left out)

so just off these charts, that cam has a theoretical operating range to about 5~55


so running out of steam around 5K seems about chalk. upping the carb might net some R's if the exhaust is up to the task. also, if it's a knock off air gap that too may be an issue. heck, even the ignition may play a role there too.

there's a whole mess of variables here and any single or combination of them could result in the scenario.

 

[Bewy]

With a 5.9, I would say that cam will be done by 5000-5200 rpm. It is not a very big cam, the 050 duration is very close to the 440 Magnum cam.

 

[273]

With a 5.9, I would say that cam will be done by 5000-5200 rpm. It is not a very big cam, the 050 duration is very close to the 440 Magnum cam.

I'd say it would probably peak there but shouldn't be done especially with ported heads (depending on porting) cid cam and heads main ingredients for powerband, intake exhaust can tune for stronger and narrower or broader and longer rpm range.

 

[Slantsix64]

Damn, I was hoping that it was lack of fuel feeding the motor in the top end, I still have the stock fuel pump and 5/16 fuel line

It’s not a stroker motor, stock bottom end 5.9 ported heads, Hughes valves and retainer kit.

Maybe I should of went closer to the magnum 400hp camshaft

 

[Slantsix64]

The engine will start popping/choking if I go past 5200 rpms manual shifting

Timing is 12 initial and 18 mechanical

 

[273]

Damn, I was hoping that it was lack of fuel feeding the motor in the top end, I still have the stock fuel pump and 5/16 fuel line

It’s not a stroker motor, stock bottom end 5.9 ported heads, Hughes valves and retainer kit.

Maybe I should of went closer to the magnum 400hp camshaft

I'd say it's probably in the tune or something, guessing you upgraded valve springs.

Power shouldn't drop sharply off at 5100 rpms.

 

[Slantsix64]

I'd say it's probably in the tune or something, guessing you upgraded valve springs.

Power shouldn't drop sharply off at 5100 rpms.

Yes I did upgrade valve springs, when the power drops off I can hear it pinging that’s why I was leaning more towards fuel delivery. My total timing comes in at 2800 rpms I don’t understand why it’s pinging at 5000rpms

 

[DMC_78]

Damn, I was hoping that it was lack of fuel feeding the motor in the top end, I still have the stock fuel pump and 5/16 fuel line

It’s not a stroker motor, stock bottom end 5.9 ported heads, Hughes valves and retainer kit.

Maybe I should of went closer to the magnum 400hp camshaft

Interesting post for me. I built a very similar combo with the Hughes version of this cam.

 

[TT5.9mag]

What carburetor? And what’s the fuel pressure at 5000 rpm WOT?

 

[TT5.9mag]

When a camshaft falls out of its rpm range the engine doesn’t “pop and bang” or “ping”. They just don’t continue to make power. You can keep revving it till the cows come home or the valves meet the pistons. You sir have a fuel or tune up problem.

 

[teringer]

Check your timming at 3000 and 5000rpm you could have too much timming a lot of people never check it at top speed and have seen many engines break timming chains and destroy the top end when the exhaust valves sizes in the guide from donations in circle track engines

 

[Dart Frog]

I think you need more valve spring. popping that you're describing sure sounds like valve float. Were you precise on installation height of the valve spring. If your installation height wasn't correct valve spring pressure could be off.

 

[Slantsix64]

Dang I honestly only measured piston to valve clearance. I ran the Hughes retainers and locks springs kit.

 

[Slantsix64]

60ft was 1.9

 

[Slantsix64]

What carburetor? And what’s the fuel pressure at 5000 rpm WOT?

It’s a Holley 3310, fuel pressure I don’t know there’s no gauge on it. I’ll probably install one I’m guessing the fuel pressures should stay at constant 6-7 psi even in the upper rpm’s

 

[middleagecrisis]

If you’re going to go to the expense and effort to change the cam from what you have, I would personally go bigger than that. Did Ken recommend that cam for you?

 

[cookietruck]

My guess is valve float if it starts missing/popping.

Stock rockers?

Which hughes springs and did you verify install height?

 

[TT5.9mag]

It’s a Holley 3310, fuel pressure I don’t know there’s no gauge on it. I’ll probably install one I’m guessing the fuel pressures should stay at constant 6-7 psi even in the upper rpm’s

Ive had that same problem with 3310s. I bet it’s lean. Measure fuel pressure as a start. Don’t chase valve float just yet.

 

[360duster]

Something´s wrong with your engine, we ran this cam in a stock bottom end 5.2 with home ported cylinder heads - best et 12.7 with 3.55 gear (70 4dr Valiant). I really liked this cam, it worked great.

Michael

 

[Slantsix64]

Ive had that same problem with 3310s. I bet it’s lean. Measure fuel pressure as a start. Don’t chase valve float just yet.

thats what i was thinking, its starving in the upper rpms fuel delivery issues, i have 70 primaries and 76 secondaries 10.5 PV in the carb best runs were with the white secondary spring.