Re-Rebuilding the 440-493 in a 1970 Charger

[Wietse]

Depends on the cam maker I think, my valve springs are at #150 seat pressure for my hydr. flat tappet. (around #340 over the nose)
Supposed to remove the inner damper for break-in though.
Need to check what are requirements for break-in for the cam he is using and what springs/pressure are tolerated, don't go by general guide lines.

 

[Dodge Bros]

Checking a cam for low lifts like .003-.004 tappet isn’t going to gain any info on a performance cam. That is SAE type info for emissions parameters, some cam grinder call it “true seat timing”. You can’t really use that type of info for any type of useful calculator to predict much of anything. It will just confuse you. By the time the engine get’s up into it’s power band and has deflection & absorbs the shock of the valve terrain the actual timing events are well behind that. For comparison, an old OEM big block magnum cam has more seat timing at .004” than any of the cams so far in this thread. If you have ambition to check the specs out on a cam for seat timing, work backwards from 009” lift out at the valve for closing and opening points. Measured off the actual cam. That .009 at the valve, is .006 tappet with 1.5s that many hyd cams are advertise at. On different rocker ratios work backwards to the tappet lifts, on solid that it is after the lash is taken out. I have found it useful, it cuts thru a lot of advertising BS, like what was on that Lunati cam card. Check it not just on the closing side, but on the opening side as well.

Some say that seat timing do not matter, and the .050” are all that matters. I think that is complete BS. There are a bunch of small cams that by the time the valve is at .050” tappet the other valve is shut. Those .009” valve lift points (.006” tappet lift with 1.5 rockers) are the main reference’s for cams overlap, (overlap triangle). It tells the cams intensity to .050”, which on assymetric’s cam’s is different between the opening and closing. That can have a large effect on DCR. That old Lunati was probably a symmetrical cam, with its original masters designed back in the 80s. That much overlap and much for exhaust restrictions on that type of cam tends to add lot of extra heat up the into the intake air charge. That would be my guess as to why it wasn’t pump gas friendly compared to the 509 purple cam. By my rough calculations the Lunati and a 509 have close to the same overlap. The Lunati has a few more degrees by .050” after the lash, and is likely a .842” lifter profile. From what was described on the cam change to the 509 I think it is always going to be a bit of a temperamental pump gas cam. There is a lot more to this than just pumping compression, no argument from me. If the car spent it’s life go back in forth to the drag strip, sure, put that Lunati back in. If you want to drive it a lot, there are much better cams options than that Lunati. With a point lower compression there will be a lot of good options for cams better than that one. More $$$ is the only down side.

 

[PRHeads]

The way I’m understanding it....... in this example, the Lunati had the highest cranking pressure, was the most octane dependent(the most ping)...... and made the most power(car was the fastest).

I’d say....... if you’re on the edge of having detonation issues, or are straight up having them already....... and you swap the cam and the cranking pressure is higher with the new one........ you haven’t solved the issue.

With a point lower compression there will be a lot of good options for cams better than that one.

Agreed.
With the thick head gaskets the compression was lower enough so that the 528 cam worked satisfactorily, which imo was a better cam for the application, overall.
I’d be looking at something along those lines myself.

 

[Dodge Bros]

I would say that is pretty spot on PR. I have been on board with the drop in compression. After Kern described some of the things that occurred with the Lunati cam swap, I don’t think I would go back with it even with the compression drop.

A couple years ago I shipped a custom Bullet cam overseas to help with someone’s detonation issues . It was someone’s daily driver in Middle East, running E heads. That was only pumping 160 psi before I did the custom cam. Lol, you think pump gas sucks in CA. We have it pretty good!

 

[Kern Dog]

I added air conditioning and a 5 speed to make the car more comfortable to drive.
Fast is fun but a sweaty asscrack and frazzled nerves from 4000 rpm freeway trips puts the kibosh on fun right away. It must be human nature to always want more or to change things. A year or so after pulling the Lunati to install the ‘528, i was missing the power that the Lunati provided.
I often remember the good times and forget the bad times.
The appeal of the Lunati at this point is that I know the power it made and I’d be able to breath easier regarding break in. I’ve had mysterious “no spark” issues crop up on first fire. It is very frustrating to deal with that at a time when it is crucial to start and run right away.
That said, I’m not committed to anything yet but a roller sure alleviates the anxiety of a camshaft break in procedure.

 

[Fran Blacker]

What about advancing the Lunati some if you lower the compression. Think it would improve street driving. Any comment PR heads/Dodge Bros? I get your reason for not buying a new cam and lifters it's a crap shoot.

 

[Kern Dog]

I did advance the Lunati after having it set up as first directed. The low speed performance improved. With the thicker head gaskets, it didn’t knock with the Lunati.
One more nugget regarding the Lunati....
I’m going down 3-4 tenths of compression while closing my quench distance from .087 to around .045. I’m no expert here but isn’t quench supposed to help reduce detonation?

 

[Kern Dog]

I stripped down the K member to prep everything for refinishing.

Back in 2003, I painted everything because I didn’t want anything to collect surface rust. The k member, UCAs and LCAs were painted black. The steering linkage and strut rods were painted a dark gray metallic Since then, everything has chipped and scratched a bit. I decided to strip the k member with a wire wheel on a 4.5” grinder.

 

[Kern Dog]

These will get epoxy primer, base black and a semi gloss clear.
For the rest, I’m going to strip the paint, sandblast then treat them to the RPM Rust Preventative Treatment from ECS.

 

[furious70]

Man, don't you wish you had just swapped the cam?

 

[PRHeads]

what was the compression with the old pistons and thick gaskets vs the new pistons and normal gaskets?

Since you ran the lunati with the lower CR(thick gaskets) already, then swapped to the 528, you should have a pretty could feel for the “cause and affect” difference between the two.
Imo, those two cams represent a difference I would consider to be more than “one step” apart.
Meaning....... there is some area in between the two where you could lean either more towards the power aspect of the lunati or the drivability aspect of the 528, without going all the way to either end of that spectrum.

 

[Kern Dog]

I would certainly consider a roller cam that is something between the Lunati and the ‘528.
To summarize:
The engine started out at 10.8 to 1 with .039 head gaskets and the ‘509 cam. I switched to .060 head gaskets and a Comp XE 285HL. It failed so I swapped in another. It failed so I pulled the engine, honed it and put it back together with the .039 gaskets and ‘509 thinking I could get by with mixing a little race gas and tuning to get it right.
It knocked at anything over 3/4 throttle.
I swapped in the Lunati and it knocked worse.
I put in .075 head gaskets and it didn’t knock. It ran strong but idled a bit rough. I advanced the cam 4 degrees and it smoothed out a bit and still did not knock. I wanted a bit smoother street manners so I installed the ‘528.
The Lunati saw 10.8 to 10.9 compression and 10.1 compression and seemed to do fine with both but the 4 degree advance made it slightly more livable.

 

[Dodge Bros]

Do you recall where you set the ICL position with the Lunati?

Lunati or the 528, a roller cam could make gains everywhere on top end power, average power, and drivability. Maybe not much difference in drivability on the 528, it is a pretty small cam.

It sounds like your ending up with the compression not far from where it was ran before, any improvement’s will just a better quench, better quench certainly won’t make anything worse. But, if the Lunati wasn’t pinging before with the thicker .075” cometics, the tighter quench isn’t really adding much over how it ran before. Sitting in traffic with the A/C on, the Lunati would for not be a cam I would want to run on the street a ton.

 

[Dodge Bros]

Wow. I did not catch that this last cam was third one to go flat…

Time too look at rollers…

 

[Wietse]

Those rollers run a lot smoother with those rounded profiles

 

[Kern Dog]

Do you recall where you set the ICL position with the Lunati?

This was my first attempt at degree-ing the cam. I set it to exactly what the cam card called for. 106. I later advanced it to 104.

 

[Kern Dog]

The K member had a few sloppy welds so I rolled out the MIG and cleaned it up a bit.

The lower control arms were wire wheeled, then sandblasted....

I keep finding little bits of paint hiding here and there. The goal was to clean these up and coat them with the RPM paste to keep them looking like freshly made parts. I'm not a restoration expert by any means but I do like to follow some factory type methods. I'm leaving the steering linkage in a natural type finish. From what I have read, the lower control arms are supposed to be natural finish too. I'm going to round off some rough edges and brush on the RPM paste on these LCAs and see if I like the look. I don't know how long this coating lasts but once it wears off, I suppose all I'd need to do is clean whatever surface rust I see and reapply the RPM paste.

I didn't want to put the steering linkage in the sandblaster. The sand would surely get into the tie rod ends. Instead, I wire wheeled everything then scrubbed the surface with 400 grit sandpaper with soapy water. I'll have to do this a few more times to get the sheen even. I may use a red Scotch Brite pad if needed. These will get the RPM paste.

This is the RPM paste I mentioned:

 

[beanhead]

Nice work dude

 

[Fran Blacker]

Doesn't that RPM paste need to be periodically need to be redone? If so I'd satin clear them. Great job!

 

[Dodge Bros]

This was my first attempt at degree-ing the cam. I set it to exactly what the cam card called for. 106. I later advanced it to 104.

I still do cam timing like the Mopar performance books with 2 more degrees installed advance to closer simulate what the timing is actually doing when the engine is operating and not just being cranked over on the engine stand. It has always made sense to me to use numbers that are closest to how the engine is operating. The extra 2 advance would not apply though if your cars is running a belt or gear drive, just for roller timing chains. 104 is where I would install the cam to run it on 106 to match up with the cam card. Installing it at 106 to me is straight up running on 108.

Appears 106 is the ideal place where the intake and exhuast triangle is squared up at top dead center. It is completely squared up at 105.5. It will probably run of 4* either side of that on the ICL. ICL Installed on the negative side of that is open header territory.

I think the Lunati would run the hardest with full exh, A/C, manual trans car installed at 102, the cranking compression would go up about 8 lbs, but I would knock it back down with the intake lash tightened to .016-.018”, and the leave exh at .024”. That is what I would do if it was my car with the Lunati.