High dollar composite lifters

[Alex22]

open pressure means little to me. i do like to see the number but the seat pressure is where it is at.

Why does seat pressure means so much more than open pressure? Is it because that is where the cam spends most of its life?
If there is not enough pressure at the seat when the valve closes it may not stay shut and the valve will bounce off of the seat causing it to pound the face of the valve. Monster springs don't damage the face of a valve, weak pressure at the seat does. The pressure at full open has more to do with how well the lifter stays attached to the cam.

what is the stock seat height on this head we use? sometimes mopar uses a bastard height and its tough picking springs.

1.64"
Back in the day it was not uncommon for Chrystler and AMC to use a lot of random sizes for everything in their engines. Some blocks would not be machined properly at the factory so they would overbore just 1 cylinder to .010 or .020 over and put a small stamp on the block. If one spring pocket didn't come out right I wouldn't be supprrised if they put a different spring in instead of junking an entire head.
The 4.0's were built correctly from the factory and I have yet to hear of Jeep using the old tricks in their newer engines.

~Alex

[Flash]

Here is a though.......................

We know that the harmonic of the cam is what cause the timing change to snap a higher rpm.(over stock)
I my be completely of base here, but here go's..................................

Lets say we are spinning the motor in this Harmonic zone, were the timing change is being abused and trying to brake BUT There was no lifter, push rods or spring pressure on the cam............would that harmonic be there????????

(Does any one now how much lighter the Composite lifters are compared to a standard ones? )

It has been suggested, that if a roller cam was made that was tough enough to allow are eng to run safely at 6500 RPM, that it would be more appealing.

OK NOW TO THE MEAT OF MY THOUGH.
If the lighter composite lifter, could us less spring pressure with out floating,.......wouldn't this put less stress on the cam/chain causing the Harmonic to be less or maybe even moved up the RPM scale further............................................


Flash

[1bolt]

well, if I've got a correct understanding, the Cam is prone to the 5300 harmonic because A) its longer than most cams (longer means less rigid all things being equal a longer cam will flex more laterally (end to end) and torsionally (like ringing out a wet towel). And B) because it only has 4 bearings, there's a lot of room between the bearings for the cam to vibrate...

What causes the vibration? The rest of the valve train, so yeah lower stress from the valve train, is like plucking less hard on a guitar string, the harmonic would still "sound" (unless the cam was made more rigid or shorter or longer thus changing its natural frequency or "tune") but it might not be as violent a vibration.

If you pluck a guitar string lightly you get the same note as if you pluck it hard, only the volume of the sound is different... Volume is amplitude... amplitude is basically how gentle or violent the harmonic is. It's the height and depth of the wave form.

So lighten the lifters, put titanium valves in, lighten the spring pressure or put roller lifters in, and the harmonic will vary in amplitude... probably considerably lower. Just how much is anyone's guess, enough to rev safely past the mid 5k RPM range on a regular basis? Maybe...

Barney Navaro took the same basic block design and spun it past 5k all the time on the way up to 7,000 at Indy... but he had a fuel pump on the end of the cam.... which had to act as somewhat of a harmonic balancer. So it's not an insurmountable problem.

[Flash]

Thanks 1bolt!
Always Enjoy you thoughts and insight!

So it's simple....Roller cam, Composite lifters, alu rocker arms, titanium valve retainers and locks. Twist it to 7,000 rpm...............ah, Pocket change

.....It would be nice to keep the stock spring, a cam that you know need stiffer spring. add a light composite lifters and twist it up,(rpm).... a little bit more.........In theory any was

Flash

[John]

1 bolt, I think you have a fine grasp on this, just modify the oiling system now.
John

[1bolt]

yep oil starvation at the crank is the next problem according to Lee Hurley. Fixed by cross drilling.

Lightening the valve train will have lots of other beneficial effects besides the theoretical benefit of passing the harmonic. lower resistence on the cam lobe will equal less heat, less wear and less friction, less mass will make it rev faster and higher.

I would say that if composit lifters can be had for significantly less than a roller cam. then they would be a great upgrade. Just knowing you wont wipe a lobe from ZDDP/poor lifter quality issue might make them worth a couple hundred more than regular lifters... but $500-600 seems pretty hard to justify on a bang for your buck basis.

[1bolt]

oh by the way I just looked at that lifter company linked earlier in the thread and what do they say right on the opening page:
"Helps Eliminate Valve Train Harmonics"

For what its worth I hadn't read that before I posted my opinions above, seems to corroborate the idea that less mass in the valve train lowers the effects of harmonics. If you can take manufacturer selling points as at least somewhat truthful

[Alex22]

I plan on calling up 4secondsflat tomorrow on my lunch break to find out what the lifters are actually made out of and how much they weigh, because up till now everybody is assuming they are lighter than stock steel ones. It does appear to be an aluminum body with an insert pressed into it. If it is a ceramic insert I would stay very far away from them. My boss said that a few years ago Joe Shubeck had a booth at the PRI show showing off his ceramic lifters, last year he didn't have a booth there and all he head was people cursing Joe up and down and talking about how a ceramic lifter broke and wasted entire race engines ($20,000+ in damage to some). Maybe these are a different composite, but I have checked around and have not been able to find out any info on these specific lifters.

~Alex

Edit: Try not to take this is me pissing in your Cheerios. If you would like to try them just be aware of what has happened to other engine builders, and report back to us how you like them.

[Flash]

Psssssssssssssssssssssssssssssss

It would be vary nice to know if/or, how much they weigh........keep up informed

Flash

[1bolt]

yeah what Flash said.

FWIW Ceramic lifters have been around for a some time, and yes back in the 90's there were some cases of ceramic lifters actually breaking shattering with pieces ending up in the oil system, and the resulting completely f'ed engines. From what I remember even back then they were isolated, and only happened with some particularly brittle ceramic lifters under extreme valve train loads.

Anyway I agree it seems like something worth looking into... I was wondering if the black end wasn't some type of carbon or kevlar composite.

[Alex22]

I talked with one of the guys at 4SecondsFlat today. The lifters have a steel body with a ceramic face on them. He said that he has been running the same set of lifters in his car for 6 years with no problems. When I mentioned all the horror stories about the ceramics he said "let me guess, you heard it on the internet." I told him about the area shops and about what the builders at PRI were saying. He just dismissed them as "builders fault/not setting them correct." I'm staying far away from these, I just don't want to chance my daily driver.

They still have the steel body so they might be a few grams lighter than the standard lifters, but don't count it as a miracle cure for the harmonics.

~Alex

[Flash]

Hmmm Yeah i was hoping that you were going to say that they are 1/2 the weight or something
the lifter is probably the heaviest part in the valve train(I no spring create pressure/weight)

My self i still find them vary interesting,...............if you were testing a bunch of cams, the composite would pay for its self in a big hurry......................................


Alex22, You didn't happen to ask him what the "cam life" was compared to stock lifter, did yeah?


Flash

[Alex22]

The guy seemed a little grumpy, maybe I just woke him up from a nap or something.
Flash, the number for 4SecondsFlat is listed on their websit, but remember you are talking to a salesman and not your machinist.

~Alex

[Muad'Dib]

There only about 136 miles from me in Cottage Grove Oregon.