Re-Rebuilding the 440-493 in a 1970 Charger

[Dodge Bros]

I read thru your thread. The engine bay is looking great. You have an awesome charger. I’ll add some thoughts to some of the engine issues, you already have most everything figured you though. The way in which the cam failed, with many tappets showing a lot of wear, that does appear to be a lubrication issue, likely do to that change in oil you made. Jmho

You already figured this out the hard way back when you went to the thicker head gaskets…but that Lunati cam is not really a cam that bleeds compression very well, and really is changing very little from the 528 purple cam for fuel requirements. At a glance it appears to be an early grind before Lunati aquired the Ultradyne’s grinds. The info provided in the cam card’s advertised seat duration rating are likely at a much lower tappet rating than most solid cams (most are rated at .020” tappet). That cam appears to be rated at closer to .012-.014” tappet, likely based from the original design lash at the tappet. If you want to compare it to other cams the advertised rating would probably be about 296 int and 306 exh at .020” tappet instead of the 316, 326 number printed on the cam card.

Comparing the Lunati’s earlier installed ICL position and the 528 Purple cam with the wider 112 LSA and it’s later ICL position you likely didn’t change your cranking compression much at all between those 2 cams, and provided very minimal changes in the engines octane requirements. The Lunati cam would be a little more pump gas friendly than 528 purple cam, but it was never going to make the difference you were hoping for. The Lunuati cam likely did really respond to race gas and higher compression with more top end. It is still going to run really hard with lower upper 9s compression, mostly street duty I doubt you will notice a power difference with less compression. Only thing you would notice is the idle will be a little snottier. Your new compression goals sound spot on to me if your using the Lunati again.

 

[Kern Dog]

Thank you.
To be clear, I had a Mopar 292-509 in the engine before switching to the Lunati. At the time, I was advised that a "bigger cam" may help reduce or eliminate detonation so I took the advice on the Lunati cam. A guy that posts heavily on FABO suggested the Lunati so I went with it.
Comparing cam specs, it is difficult to know what is what when each cam is measured at different points. I understand that there is a reason that companies measure at different points but when they all arbitrarily use their own methods that don't line up with others, it makes comparisons really difficult.
For years, Ma Mopar didn't publish their duration @ .050 numbers. They simply suggested that you multiply the advertised duration number by .85 and even that was a guess. This was not helpful to guys that wanted to compare products against the competition.
Given all of that....I was under the impression that the Lunati had a later intake closing point than the '509. The later intake closing is supposed to result in less cylinder pressure.
The average cranking compression with the '509 was 187.7. With the Lunati, it was 191. After installing the thicker head gaskets which dropped the static CR to approx 10.1, the average went to 159.5.
I advanced the Lunati 4 degrees and the numbers bumped up to an average around 165. I should have recorded cranking #s with the '528 cam but I can't find anything in my notes. I did record that the '528 idled a lot smoother and produced double the idle vacuum. I didn't drag race the car with either cam in place.

 

[Dodge Bros]

I didn’t catch that you had the 292 cam. The 292 has a little more seat timing than your Lunati cam, i think they are right around 300* at .006” tappet, 248* @ .050”,best I recall anyway. Like I mentioned that Lunati is likely in the neighborhood of 296*. With the lash taken out it is around 250* @.050”. The slight decrease in seat timing with the Lunati was why you had the slight increase in cranking compression between those 2 cams, installed ICL increased it some also. The 528 cam wouldn’t likely crank much different pressures either. For sure the 528 is the friendliest on the street. The bigger exh duration (extra 10* split) on the Lunati is the main gain in pump gas friendliness with the Lunati over the 509 or the 528. Other than that they will pump fairly closely for a compression test. If anything the I think the 528 would be the highest on cranking pressure, but it’s wide LSA makes the power a little smoother, it is able to run a little higher compression against the other two cams with the 108 LSA. You could swap any of those cams and have pretty similar octane needs.

 

[Kern Dog]

The car knocked worse when I pulled the '509 and installed the Lunati. This is where I started to get confused. The Lunati was supposed to reduce the knock but instead, it made it worse. It ran strong with 110 octane but knocked on 91. That is why I dropped the compression ratio with the thicker head gaskets.

 

[Kern Dog]

I'm getting ready to disassemble the steering and K member stuff. Back in 2003, I painted everything to avoid flash rust. Over time, the paint has chipped.
I just ordered some of this:

This stuff is applied to bare metal parts to keep them looking new...as cast or as forged whatever they may be.

 

[Kern Dog]

All this time and I had no idea you had a lift in your garage! Awesome.

 

[68 Sport Satellite]

View attachment 1301925

We need a HAHA emoji.

 

[MarPar]

We need a HAHA emoji.

 

[PRHeads]

The car knocked worse when I pulled the '509 and installed the Lunati. This is where I started to get confused. The Lunati was supposed to reduce the knock but instead, it made it worse. It ran strong with 110 octane but knocked on 91. That is why I dropped the compression ratio with the thicker head gaskets.

The concept of curing a detonation problem caused by a higher CR than what the desired fuel to be used will tolerate is fundamentally flawed...... if you’re trying to maintain “high performance”.

In the case of swapping the 509 for the lunati ..... the Lunati cam did it’s intended job.
Allow more air and fuel into the engine, and increase power by producing higher cylinder pressure.

There is way more going on with the relationship between the overall engine combination and the cam than just the intake closing point.
The Lunati cam was more effective at boosting the “running dynamic compression” than the 509 was.

You’d have to put in a cam that was just “waaay too big” to work with the CR in order to make the motor inefficient in the rpm range where the detonation is most prevalent.
Big enough to “bleed off” cylinder pressure.
You’ve got to numb up the motor.

Cylinder pressure is power.
You want as much as the octane you’re using, in your particular combination will tolerate........ if you want power.

in KD’s combo, the lunati pumped up the cylinder pressure(more power) beyond what was seen with the 509 cam.

To try and guesstimate how much different the cam would have to be, you could play with an on line dynamic compression calculator, and keep adjusting the intake closing point until the cranking pressure is enough lower than what you have, to get to a point where it might not knock.
Then fill in the blanks for the rest of the events to go with that....... while keeping in mind you’re trying to make the motor less efficient.

What you’d likely end up with is something not at all well suited for the overall combo, that was kind of a dud to drive......... but it might not have a spark knock issue.

 

[Wietse]

What if he had retarded the 509 cam to bring down the DCR, you will lose some power spirit but it shouldn't it become less sensitive for detonation?

 

[Kern Dog]

The concept of curing a detonation problem caused by a higher CR than what the desired fuel to be used will tolerate is fundamentally flawed...... if you’re trying to maintain “high performance”.

In the case of swapping the 509 for the lunati ..... the Lunati cam did it’s intended job.
Allow more air and fuel into the engine, and increase power by producing higher cylinder pressure.

There is way more going on with the relationship between the overall engine combination and the cam than just the intake closing point.
The Lunati cam was more effective at boosting the “running dynamic compression” than the 509 was.

You’d have to put in a cam that was just “waaay too big” to work with the CR in order to make the motor inefficient in the rpm range where the detonation is most prevalent.
Big enough to “bleed off” cylinder pressure.
You’ve got to numb up the motor.

Cylinder pressure is power.
You want as much as the octane you’re using, in your particular combination will tolerate........ if you want power.

in KD’s combo, the lunati pumped up the cylinder pressure(more power) beyond what was seen with the 509 cam.

To try and guesstimate how much different the cam would have to be, you could play with an on line dynamic compression calculator, and keep adjusting the intake closing point until the cranking pressure is enough lower than what you have, to get to a point where it might not knock.
Then fill in the blanks for the rest of the events to go with that....... while keeping in mind you’re trying to make the motor less efficient.

What you’d likely end up with is something not at all well suited for the overall combo, that was kind of a dud to drive......... but it might not have a spark knock issue.

I still don't know that much about the dynamics of bigger cam to "bleed off" cylinder pressure but I have learned that what you have written here is true. That method is a Band-Aid at best. Thanks for spelling it out better than I could.

 

[RemCharger]

Also I believe overlap plays a significant role, and I didn't see or interpret it from your lunati card, but iirc the 528 is 60* and the 509 is 76.
I put a 528 way back in a smogger over a 509 for the reason of dcr and torque.
Ran 12.10s in a full body stock 64 dodge.

 

[Geoff 2]

It was Harvey Crane that introduced the '050' number for cam selection. He claimed [ & I think he got it right or pretty close ] that this was where meaningful cam action started & was [1] more accurate for comparing brand A cam with brand B and [2] gave more accurate info on the expected power range . This was at a time when Herbert was advertising cams with 400* of duration & cam companies were dreaming up these nonsense numbers.

 

[Wietse]

You are right there Geoff.
It's good they set a certain point to compare different brands instead of throwing some crazy numbers.

I did find that Hughes Engines had their old series cams advertised duration taken at .008" and given the duration at .050".
Their current generation camshafts does not even tell the "advertised" duration anymore, only the .050".
Advertised numbers are a theory anyway, very hard to determine exactly while degreeing a cam and not as meaningful as the .050" readings.

 

[PRHeads]

I still don't know that much about the dynamics of bigger cam to "bleed off" cylinder pressure but I have learned that what you have written here is true. That method is a Band-Aid at best. Thanks for spelling it out better than I could.

It’s absolutely a band aid....... and not all that effective one in many cases.

In your case, 187psi on the gauge was too high for the fuel you were using.
165 worked okay.
How much would you have to change the cam(while leaving the rest of the combo as is) to get the cranking pressure to go from 187 down to 165?
It’s not going to be a “few degrees”.

(Edit- after playing around with a Wallace calculator, looks like the actual intake valve closing point needs to be delayed about 12* to lose roughly 20psi cranking pressure.
One way to get there would be to go from a 292*-108lsa cam in at 104........to a 304*-112lsa cam in at 110.

Lowering the compression from 11.2 down to 10:1, and retaining the original 292/108 cam in at 104 shows the cranking pressure to drop 19psi.
However, with this approach you get to retain the appropriately sized cam.)

Basically, the approach would be to use some low intensity old school lobes with long slow ramps........ long duration, and a wide lsa to delay the intake closing point quite a bit, along with kill off the effectiveness of the overlap
Then you could also use an intake manifold that was less effective in the lower rpms to further reduce the effectiveness of the overall induction system in that range.
The goal being to reduce the “running dynamic compression” enough to lower the cylinder pressure to the point where the crap gas won’t ping.
Oh yeh, slowing down the advance curve might be necessary as well.

If that doesn’t sound like something that would deliver a rewarding seat of the pants driving experience for a street car........ you’re right.

 

[Kern Dog]

I’m a little slow sometimes but I get there eventually.
The dished pistons are what I should have had in this engine all along. I bought the rotating assembly from a company in Tennessee.
Suppliers back east have access to higher octane gas than we have here. He assured me it would run fine on pump gas. I should have done my own research though.

 

[PRHeads]

If you install a solid lifter cam back into the engine, and you want to know the “true” intake closing point, you’d need to have the valvetrain at least partially installed while the degree wheel was still installed.
With the cam degreed in to the desired position, set the lash on an intake valve to the desired hot operating lash.
Rotate the crank around until the intake valve is on the closing side, nearing the closing point.
As it gets very near being closed, check to see that there is still tension on the pushrod.
As soon as you feel the pushrod no longer has tension on it, read the degree wheel for the number of degrees ABDC.
That’s your true intake closing point.

If you’re using a hyd cam, you need to use a solid lifter and have the clearance set to like .002-.003” lash.

 

[Kern Dog]

Excellent idea, Dwayne.
I am still considering options regarding the camshaft. The only thing keeping me from re-using the Lunati is the risk of future failure. Most people seem to do well with the proper oil and spring in place. I seemed to get by with the VR-1 and the Edelbrock springs with the Lunati.
I know that there are no guarantees in life or this hobby.

 

[Nxcoupe]

To be filed in the “While I am here” file.....
I decided to pull the power booster and master cylinder and switch to an aluminum manual master cylinder.
This setup is OEM for a 73-76 A body.

View attachment 1297073
Back when I first swapped front discs on the car in 2000, I didn’t know what parts interchanged. I took this booster from a wrecked Dart and dove in to see if it would fit. To my surprise, it bolted up as if were supposed to be factory equipment.

View attachment 1297074

View attachment 1297072


I did replace the master cylinder some time ago.
While a bit bulky and heavy, it is a reliable setup. All together, it weighs...

View attachment 1297076

View attachment 1297077

I used this same setup when I put a hemi in my 71 Cuda back in the day. Worked great and cleared perfectly.

 

[Nxcoupe]

The replacement valve springs came on Monday.


View attachment 1299608View attachment 1299612

Looking at the tech sheet....

View attachment 1299613

The highlighted section shows the max lift with the springs....

View attachment 1299614

How can this be right? The '528 cam and 1.6 rocker arms were at .563 lift.
The Lunati was even higher and I didn't have any troubles. Am I reading this right?

I know I'm probably late to the party, but that is hydraulic roller seat pressure. It will wipe the lobes on break in. I had an issue with eddy apec springs with one of their flat tappet cams. Wore 2 cams out on break in because customer brought the parts and insisted I use them. Springs were about 50 psi at the seat too high for a flat tappet.