Hydraulic roller Rhodes lifters in attempt to tame cam

[jake17201]

Have a street 408 that I’m trying to make a little more tame and smooth at idle
4 speed 3:55
408 eddy head
239 243 hydraulic roller on a 112 lsa - mrl grind
Vacuum is about 12 at 1000 rpm
89 la roller block 10:1
Timing is 20 initial 32 all in

Hughes makes a fast bleed magnum style lifter, I was thinking of using them on the intake side only to knock the edge of at idle and allow me to set a 900

Any experience with this ?

 

[dano]

Have you tried more initial with that cam? Is your goal a better idle or more vacuum for brakes?

 

[Ant]

Timing is 20 initial 32 all in

I don't see tame street cars with 20° of initial ignition timing.

 

[jake17201]

I get starter kick back at 22 deg initial. Car runs great. Love the power. But below 1000 she’s flopping around the engine bay like a fish. Mancini mag mounts are securing it the bay, tried a couple different carbs. Just can’t seem the get the engine to sit still below 1000 idle. Cranking compression is 170-175 on all holes. Brakes are working good at the 12ish inches provided

 

[RustyRatRod]

I get starter kick back at 22 deg initial. Car runs great. Love the power. But below 1000 she’s flopping around the engine bay like a fish. Mancini mag mounts are securing it the bay, tried a couple different carbs. Just can’t seem the get the engine to sit still below 1000 idle. Cranking compression is 170-175 on all holes. Brakes are working good at the 12ish inches provided

Jake what distributor do you have in it?

 

[jake17201]

Fbo box, ballast bypass, fire core distributor

 

[jake17201]

I was thinking of getting a Schumacher strap or the fast bleed lifters, last resort is a smaller cam about 15 degrees less at .050

 

[George Jets]

What ignition, coil and spark plug gaps are you running?


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[jake17201]

What ignition, coil and spark plug gaps are you running?


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Fbo setup, autolite 3924
Previously had one step colder on plugs, went warmer this time around

 

[George Jets]

Have found that the Mopar HEI ignition conversion with the 60,000 volt E-Core coils, and the spark plugs gapped at .050 ths are more friendly to a better idle.

Need to back down the timing 4° because the E-Core coils produce a faster hotter spark (that actually advances the timing in itself).

☆☆☆☆☆

 

[junkyardhero]

What ignition, coil and spark plug gaps are you running?

oh boy, here we go

 

[jake17201]

Have found that the Mopar HEI ignition conversion with the 60,000 volt E-Core coils, and the spark plugs gapped at .050 ths are more friendly to a better idle.

Need to back down the timing 4° because the E-Core coils produce a faster hotter spark (that actually advances the timing in itself).

View attachment 1716526939


☆☆☆☆☆

Have found that the Mopar HEI ignition conversion with the 60,000 volt E-Core coils, and the spark plugs gapped at .050 ths are more friendly to a better idle.

Need to back down the timing 4° because the E-Core coils produce a faster hotter spark (that actually advances the timing in itself).

View attachment 1716526939


☆☆☆☆☆

Interesting, never knew this existed
Went the FBO route thinking it was the best
I will look in to this, thank you

 

[RustyRatRod]

Fbo box, ballast bypass, fire core distributor

If it has a vacuum advance, just for kicks, try the advance can on manifold vacuum. You'll need to readjust the timing. That will allow the engine to start on just what's in the distributor and have full vacuum once running. Just something to experiment around with.

 

[RustyRatRod]

Also, should you decide to go with variable duration lifters, I would use the Rhoads Z-Max. Any other variable duration lifter is not adjustable for how much duration they take out. Rhoads Z-Max are adjustable. They must have an adjustable valve train and I assume you already have that.

 

[George Jets]

☆☆☆☆☆

 

[junkyardhero]

Need to back down the timing 4° because the E-Core coils produce a faster hotter spark (that actually advances the timing in itself).

**CITATION NEEDED**

 

[jake17201]

Before I throw in the towel on this cam I’ll give the manifold vaccum advance idea a try and keep tuning on the carb

I don’t feel like over camned the car with the 112 lsa cam and a 239 lobe…. But I guess that’s very subjective

 

[RustyRatRod]

Before I throw in the towel on this cam I’ll give the manifold vaccum advance idea a try and keep tuning on the carb

I don’t feel like over camned the car with the 112 lsa cam and a 239 lobe…. But I guess that’s very subjective

The cam in my slant 6 is a lot bigger than yours and it will idle at about 550 warm. It doesn't like it but it will. I have it sittin on about 750-800 normally.

 

[rumblefish360]

Have a street 408 that I’m trying to make a little more tame and smooth at idle
4 speed 3:55
408 eddy head
239 243 hydraulic roller on a 112 lsa - mrl grind
Vacuum is about 12 at 1000 rpm
89 la roller block 10:1
Timing is 20 initial 32 all in

Hughes makes a fast bleed magnum style lifter, I was thinking of using them on the intake side only to knock the edge of at idle and allow me to set a 900

Any experience with this ?

Yes, I’d try the ignition first and follow rusty rat rods advice on lifters. I use (and used) Rhodes lifters before a few times and they do what they say.

I have used them to tame down bigger cans than what you have. Honestly it’s more of a band aid fix for my mistake on the cam choice I made. BUT….

Use of the variable lifters on the intake is an unusual step and I’ve tried it. While I can say how well it’ll work on your application and combo, lowering the intake duration lowers the operational rpm range of the cam and engine until that lifter pumps up and no longer becomes a variable in changing duration.

RustyRatRod suggested the variable duration lifter that can vari the amount of duration to customize more so what your after. I used the regular Rhodes Hyd lifter back then.

239 down to 219????

I was thinking of getting a Schumacher strap or the fast bleed lifters, last resort is a smaller cam about 15 degrees less at .050

They work very well even though that is not designed to do what you want, but it’ll do it. I have used that torque strap several times before.

 

[TT5.9mag]

Need to back down the timing 4° because the E-Core coils produce a faster hotter spark (that actually advances the timing in itself

Stop spouting this nonsense. The coil has nothing to do with when the engine wants the ignition to fire.

 

[TT5.9mag]

Have a street 408 that I’m trying to make a little more tame and smooth at idle
4 speed 3:55
408 eddy head
239 243 hydraulic roller on a 112 lsa - mrl grind
Vacuum is about 12 at 1000 rpm
89 la roller block 10:1
Timing is 20 initial 32 all in

Hughes makes a fast bleed magnum style lifter, I was thinking of using them on the intake side only to knock the edge of at idle and allow me to set a 900

Any experience with this ?

Put more timing in it and fatten it up. 24-26 degrees at idle should smooth it out quite a bit.

 

[RustyRatRod]

Put more timing in it and fatten it up. 24-26 degrees at idle should smooth it out quite a bit.

Very likely. Costs nothing to experiment!

 

[crackedback]

Put more timing in it and fatten it up. 24-26 degrees at idle should smooth it out quite a bit.

Said he gets kickback at 22. Maybe needs better battery cables.

Bordering on rowdy with the cam and definitely big for a "tame" build.

 

[Jeremiah (jd)]

I'd be interested to kbow what the timing curve is like. Maybe you are getting mechanical advalce at 1000rpm. Does the timumg fall off a ledge at 900? I see this a lot with stupid MSD bushings that limit you to 18 degrees mechanical advance min. Should be more like 6 or 8 deg for most of the stuff I work on.

I agree with the opinion of more fuel and static ignitiin timing. Again verify that you are not getting into the mechanical Advance at chosen idle speed.

 

[RustyRatRod]

Also, check all the main battery connections, like @crackedback recommended. Don't overlook that!