340 stroker cam

-
dodgedifferent2

dodgedifferent2

Well-Known Member
Joined
Aug 8, 2008
Messages
3,133
Reaction score
992
Location
southwestern, Ontario
Ok i have a 340 stroker (418) which had a cam issue.
I am running ported indy 360-1 heads with the indy single plane intake.
10.5 compression
1.6 t&d roller rockers
4 inch molnar crank
.04 over bore.
It currently has a lunati solid roller 40200733

I run 4.30 rear gears
Passon 4 speed hemi overdrive
28" tall tires 325/50/15 nitto drag radials.
Manual brakes (power steering hyrdroboost)
Fitech fuel injection.
Tti headers with x pipe out the rear.
Car weighs about 3300-3400 lbs.

Now the one solid roller lifter broke a wheel axle and screwed up a lobe on the current cam.

I found the engine made gobs of power up high but I mainly drive on the street now with the kids. So a step down on the cam wont hurt my feelings much.

I am looking at going a cam down with 40200732 or comp 20-740-9

They are basically the same cam or should I see what else is an option?

 
dodgedifferent2 said:
Ok i have a 340 stroker (418) which had a cam issue.
I am running ported indy 360-1 heads with the indy single plane intake.
10.5 compression
1.6 t&d roller rockers
4 inch molnar crank
.04 over bore.
It currently has a lunati solid roller 40200733

I run 4.30 rear gears
Passon 4 speed hemi overdrive
28" tall tires 325/50/15 nitto drag radials.
Manual brakes (power steering hyrdroboost)
Fitech fuel injection.
Tti headers with x pipe out the rear.
Car weighs about 3300-3400 lbs.

Now the one solid roller lifter broke a wheel axle and screwed up a lobe on the current cam.

I found the engine made gobs of power up high but I mainly drive on the street now with the kids. So a step down on the cam wont hurt my feelings much.

I am looking at going a cam down with 40200732 or comp 20-740-9

They are basically the same cam or should I see what else is an option?
Click to expand...


What lifters??? If you broke one, you’ll break it again.

You need a set of Crane Pro Series lifters, or the real good Crowers (a FABO member works for Crower but I can’t think of his user name) or some similar lifter with a wheel diameter of .810-.815.

I’m betting your lifters have the .750 diameter wheel.
 
dodgedifferent2 said:
Ok i have a 340 stroker (418) which had a cam issue.
I am running ported indy 360-1 heads with the indy single plane intake.
10.5 compression
1.6 t&d roller rockers
4 inch molnar crank
.04 over bore.
It currently has a lunati solid roller 40200733

I run 4.30 rear gears
Passon 4 speed hemi overdrive
28" tall tires 325/50/15 nitto drag radials.
Manual brakes (power steering hyrdroboost)
Fitech fuel injection.
Tti headers with x pipe out the rear.
Car weighs about 3300-3400 lbs.

Now the one solid roller lifter broke a wheel axle and screwed up a lobe on the current cam.

I found the engine made gobs of power up high but I mainly drive on the street now with the kids. So a step down on the cam wont hurt my feelings much.

I am looking at going a cam down with 40200732 or comp 20-740-9

They are basically the same cam or should I see what else is an option?
Click to expand...

What lifters and what seat and open pressures?
If you went to a street solid rollers like an aggressive hyd roller with solid roller lifters on it.. you'd be problem free and power where you want it.

Call Herbert cams and ask about their. special grind street solid roller. I've had nothing but good experience with them and reliability. A lot of time it's about matching the right parts with the right cam for app. Running around town with over 500 psi open is kinda asking for problems. The rollers need a little more oil to live than a flat tappet, so there comes the higher rpm necessity driving to keep them lubed.

The entire herbert setup using a Kmotion spring, k800, only sets you back about $700
 
For no particular reason, I'd talk to Bullet Cams and go with what they recommend. I guess that's because you will get better service than from Comp....you'll talk to a real person who has some experience. I'd also show them the courtesy of having your cam specs in hand when you call; simply providing a company's part number will most likely cause them to think "How the F*ck do I know what that number means? This guys expects me to take my time to look up his cam, when he should show up with that in hand."
 
The heads were setup by shady Dell speedshop a few years ago. The springs were setup for the lunati camshaft at that time.

I am running the bam lifters with the .815 roller and .180 offset to help clear the intake. Purchased from the now defunct MRL. Heads are pushrod oiled.
 
dodgedifferent2 said:
The heads were setup by shady Dell speedshop a few years ago. The springs were setup for the lunati camshaft at that time.

I am running the bam lifters with the .815 roller and .180 offset to help clear the intake. Purchased from the now defunct MRL. Heads are pushrod oiled.
Click to expand...
Axle on wheel , no bearings. I'm not into that on the street. Idc what anyone says.

You run the part for the app. Sticking higher end race stuff in a street motor doesnt mean itll work or last. In a motor that doesn't throw oil everywhere constantly will have issues. Street for street, race for race. OEM went needle bearing for a reason...and it wasn't cheaper.
 
dodgedifferent2 said:
The heads were setup by shady Dell speedshop a few years ago. The springs were setup for the lunati camshaft at that time.

I am running the bam lifters with the .815 roller and .180 offset to help clear the intake. Purchased from the now defunct MRL. Heads are pushrod oiled.
Click to expand...


Then the other option is, because you have dam good lifters is you don’t have near enough spring load.

In May I did a .660 lift street roller and the grinder wanted 240-260 on the seat minimum. It could easily take 280 on the seat and that is a street roller lobe.

IMO, anything under 240 on the seat won’t support any decent lobe.
 
yellow rose said:
Then the other option is, because you have dam good lifters is you don’t have near enough spring load.

In May I did a .660 lift street roller and the grinder wanted 240-260 on the seat minimum. It could easily take 280 on the seat and that is a street roller lobe.

IMO, anything under 240 on the seat won’t support any decent lobe.
Click to expand...
Good thing that's your opinion.

OP, run what the grinder say... and tell him how high, realistically, you will rev it... if you find it revs past where you said.. re think the spring.
 
Talk to the lifter manufacturer, see what their take on the failure is.

For real street stuff, I like to keep the spring loads as low as possible.
I also like the cams to have conservative ramps.

If the lifter that failed is an intake with the offset...... that wouldn’t be surprising to me.
The offset cup loads the bearing unevenly.

Edit- I Looked up the cam specs and recommended springs.
Looks reasonable for a street/strip combo.

Do you know what springs were actually used on the heads, and the installed height?
 
Last edited:
PRH said:
Talk to the lifter manufacturer, see what their take on the failure is.

For real street stuff, I like to keep the spring loads as low as possible.
I also like the cams to have conservative ramps.

If the lifter that failed is an intake with the offset...... that wouldn’t be surprising to me.
The offset cup loads the bearing unevenly.
Click to expand...
I share the same thoight on the side load of the offest. I also agree with the rest.
 
MOPAROFFICIAL said:
Good thing that's your opinion.

OP, run what the grinder say... and tell him how high, realistically, you will rev it... if you find it revs past where you said.. re think the spring.
Click to expand...


Cam grinder lies, and have about spring loads.

The lie about spring loads being a measure of a junk lobe is wrong. That’s marketing and lies by competitors, you know, you’re running a brand A cam and you have issues so you call call cam grinder B and he says “those lobes that need all that spring are JUNK, my lobes don’t need all that” when in fact, he is full of ****.

Never forget, the spring manufacturers ain’t making springs with 260 or more on the seat just because they think it’s cool.

Undersprung roller cams kill parts.

Obvioulsly, the OP could also have pushrods that flex, which kills parts, but that usually shows up in other places, like making the adjusters come lose, fracturing valve locks (that’s the first tell when a set of heads comes in that the spring loads are down) or broken inner springs.

It can also kill a lifter if you have the idle RPM too slow.

I seriously doubt that the OP has the spring load too high. What’s that old saying??? Too much spring load and only YOU know. Too little spring load and EVERYONE knows.
 
I'm saying to use what you need. I'm NOT saying to use as high psi as you think you can get away with.
You should always pitch in the middle if you're trying to give accurate 'non biased/non preferenced' advice if youre trying to teach someone. Spring loads for cam A vs cam B dont translate to one being a junk lobe. Every grind has it's own requirement.
And yes , that's a good way to put it with the analogy...but you're speaking in generals when he clearly said the range was higher than he needed to begin with. So now the cam gets smaller.. and your generalization screams for more spring... well ****, we need to know where he is at seat and open before anyone can offer a good path of advice. Anything connected to mrl should be avoided fwiw.
 
MOPAROFFICIAL said:
I'm saying to use what you need. I'm NOT saying to use as high psi as you think you can get away with.
You should always pitch in the middle if you're trying to give accurate 'non biased/non preferenced' advice if youre trying to teach someone. Spring loads for cam A vs cam B dont translate to one being a junk lobe. Every grind has it's own requirement.
And yes , that's a good way to put it with the analogy...but you're speaking in generals when he clearly said the range was higher than he needed to begin with. So now the cam gets smaller.. and your generalization screams for more spring... well ****, we need to know where he is at seat and open before anyone can offer a good path of advice. Anything connected to mrl should be avoided fwiw.
Click to expand...


I looked at the spring Lunati called for, and that’s what I’d use on a HR lobe with solid lifters. They are 60 pounds down.

Then I looked up the Comp grind he posted, and they want a spring with 160 on the seat. That’s barely above SFT loads running on a roller lobe.

Most cam grinders lie about spring load. Too little spring load is way worse than too much.
 
Another issue...

I'm planning to use Isky Gold Stripe springs (not sure of which ones yet)...they're expensive. But...the guys who run them all say the same thing - they last and last.

The point being....I think a lot of guys start out with a spring that's OK in terms of pressures but the spring start to die and they all of a sudden have problems and wonder why. My inherent laziness drives a lot of decisions...and a set of springs that I don't have to mess with once they're in there has value.
 
yellow rose said:
I looked at the spring Lunati called for, and that’s what I’d use on a HR lobe with solid lifters. They are 60 pounds down.

Then I looked up the Comp grind he posted, and they want a spring with 160 on the seat. That’s barely above SFT loads running on a roller lobe.

Most cam grinders lie about spring load. Too little spring load is way worse than too much.
Click to expand...
Well lol you looked at least, I didn't.
That's WAY too low.
220 is a low end seat psi for a solid roller, and the roller lifter still failed... damn...offset or not..that's a pos . There has got to be another culprit, or else.. their just ****.
 
dodgedifferent2 said:
Ok i have a 340 stroker (418) which had a cam issue.
I am running ported indy 360-1 heads with the indy single plane intake.
10.5 compression
1.6 t&d roller rockers
4 inch molnar crank
.04 over bore.
It currently has a lunati solid roller 40200733

I run 4.30 rear gears
Passon 4 speed hemi overdrive
28" tall tires 325/50/15 nitto drag radials.
Manual brakes (power steering hyrdroboost)
Fitech fuel injection.
Tti headers with x pipe out the rear.
Car weighs about 3300-3400 lbs.

Now the one solid roller lifter broke a wheel axle and screwed up a lobe on the current cam.

I found the engine made gobs of power up high but I mainly drive on the street now with the kids. So a step down on the cam wont hurt my feelings much.

I am looking at going a cam down with 40200732 or comp 20-740-9

They are basically the same cam or should I see what else is an option?
Click to expand...

With 4 ;30 gears /power up hi ??
 
Very interesting. Hummmm
Not a horribly low cruise RPM.
 
You must log in or register to reply here.
-

Back
Top