Cam is in, car is running, now the TUNING begins!

[Sweet5ltr]

After nearly a year you have finally taken my advice, now get those gaskets on and ENJOY THE CAR! :hello2:

 

[Kern Dog]

I really hope to get something done soon. The daily commute beats me up and leaves me worn down to a nub. I feel great at quitting time but after 2 1/2 hours of driving home, I am burned out!

 

[dvw]

I really hope to get something done soon. The daily commute beats me up and leaves me worn down to a nub. I feel great at quitting time but after 2 1/2 hours of driving home, I am burned out!

First for what its worth many years ago my son had a 340 at 10.5-1, it detonated on pump 93. After installing thinner gaskets to get between .030-.033 quench it ran fine on 93. After reading this entire thread I've seen no mention of changing cam timing. Since cylinder pressure is a direct result of cam timing, why not retard the cam 2-4 degrees? Delay the intake valve closing, lower cylinder pressure. Easy test.
Doug

 

[Grabinov911]

I really hope to get something done soon. The daily commute beats me up and leaves me worn down to a nub. I feel great at quitting time but after 2 1/2 hours of driving home, I am burned out!

I hear ya brother! No longer do, but used to work in Westwood, CA - home of pretty UCLA girls, fancy movie star cars and the corner of the 405 and 10 freeways, the busiest freeway intersection in the nation. It would take me 30 minutes to get the first two miles from my office!

For what it's worth, i changed jobs and now commute only a short distance. It will change your life. You'll recover, but you GOTTA get a job closer to home!

 

[Kern Dog]

I appreciate the sentiments. I work construction and the commute distances are always changing. In Sept 2012 through March this year I was working 20 miles from home. I have 6 years to reach my 30 year pension. After that if I work anywhere, it will be a short drive!

Regarding cam timing: I have a Lunati 316/326 Solid in there now, degreed in at the recommended 106 centerline. Retarding a cam is supposed to have the negative effect of reducing power at low rpms.
I thought about trying the thinner gaskets to gain quench. The problem is, I am already at an average of 190 psi of cranking compression with the .039 gasket. A thinner one would only raise those numbers. I can't help but think that even with quench, there is a point where the cranking compression is just too much for the fuel we have here.

 

[dvw]

I appreciate the sentiments. I work construction and the commute distances are always changing. In Sept 2012 through March this year I was working 20 miles from home. I have 6 years to reach my 30 year pension. After that if I work anywhere, it will be a short drive!

Regarding cam timing: I have a Lunati 316/326 Solid in there now, degreed in at the recommended 106 centerline. Retarding a cam is supposed to have the negative effect of reducing power at low rpms.
I thought about trying the thinner gaskets to gain quench. The problem is, I am already at an average of 190 psi of cranking compression with the .039 gasket. A thinner one would only raise those numbers. I can't help but think that even with quench, there is a point where the cranking compression is just too much for the fuel we have here.

My bet is that your cam is ground on 110 LCA which means 106 is 4 degrees advanced. Installing it at 110 would actually have it in straight up. I'd rather keep the compression up and back the cam up a little. You can always move it back. The only cost is a timing cover gasket. Less work than pulling the heads. If you don't like it, move it back and then add gasket.
Doug

 

[Kern Dog]

The cam card listed the Lunati to be ground on a 108, making the 106 an installed 2 degree advance. Since I am more accustomed to milder engine builds, I went with their recommendation and degreed it to the card.
The heads were pulled in October. I had them ported and they are sitting waiting to be bolted back on.
During my long quest to stop the detonation, I've heard/read many times that my engine "should have ran fine" on pump gas with the 91 octane. I tried many things but kept hearing the knocking. After pulling the heads and seeing absolutely no signs of damage, it makes me wonder what the heck was going on. Either I was careful and lifted off the throttle in the nick of time EACH TIME I heard knocking, or what I was hearing was something else. What else could it have been though? What repetitive knocking sound could possibly occur under the same conditions? The knocking happened at full throttle using anything less than 110 fuel. I poured in some 110 leaded Sunoco and hammered the car without any knocking at all.

 

[Mebsuta]

My regular old 383 HP used to knock, or ping, with lesser grades of gasoline (anything less than 91). It sounded like castanets. It would also diesel when I shut it off. This was just a regular 383 HP with 906 heads that had been surfaced a couple of times. The cam I was using was pretty mild (222 @ .050, .465 valve lift), but it was on 108 LSA, so it raised cranking compression a little bit, up over 160 psi.

Later I used 902 heads (I told them not to surface or mill when rebuilding) and the regular 383 HP cam on 115 LSA, and now it will run on 87 octane. I think the ethanol in gasoline now helps a lot. Lots of people hate E10 but I don't have trouble with it and I like it for that reason.

I just think your compression is too high, and you have this fierce race motor that wants to give you difficulty in the street.

 

[Kern Dog]

I got lucky and got off work early tonight. I'm heading out to the shop in a moment to start reassembly!

 

[Kern Dog]

I hear about how some guys can R&R heads or entire engines in record time, but I have had mixed luck doing so. Maybe some of it is because of the car.....
I have to say that having 2" headers makes this sort of job a real pisser. To get the heads off, the headers have to come out. To get them out, the center link gets unbolted, the trans linkage too. This of course requires lifting the car to what feels like an almost unsafe height so the angle is right for installing or removing these headers. I'd never switch to manifolds, but I can see why many people stick with them.
Going back together, most of the header bolts are easily reached except near #1 and #2 tubes. I sometimes forget to tighten down the starter leads before bolting the starter in place. They are almost impossible to reach afterwards with the headers in place.
I'm almost there, just a few things on the top side to finish. I have both the Fel Pro intake paper gaskets and the thicker Mr Gasket ones. I figure that the thicker head gaskets may require thicker intake gaskets to manitain proper intake port alignment.

 

[Kern Dog]

The Charger is running again! It was dark and cold once I finished up so I didn't drive the car except 20 feet or so to wash it.
I used NGK plugs this time. Timing is set to 19 initial, 33 total. I'm sure it can take more. I need to run out the rest of the 110 octane gas and fill up with 91. That will help determine my limits. I see that most guys run between 35-37 degrees of total timing so I'll probably set it to 35. I may need to rejet the carb to maintain the right Air/fuel numbers. My wideband guage was helpful before with that.

 

[Kern Dog]

Work has been taking up so much time lately, I haven't had much spare time to mess with the car. I did drive it today though and was quite happy to hear ZERO detonation at any time.
I have about a 90% to 10% ratio of 91 octane and the 110 that was left in the tank from before the teardown. Todays drive was during 50 degree weather too. Even given that, I'm sure that the car will run fine on straight 91 even at the common 100 degree temps we get here during the Summer.
The idle feels rougher and Idle vacuum is lower. I might need more initial timing than the 19 degrees I have now. Also, I'm sure the idle mixture screws need adjustment. It runs too rich at part throttle and at WOT, between 12.0 to 13.0 at part throttle and below 12.0 at WOT. The Air/Fuel guage will be helpful in determining the right jetting I need.
Power feels great out of the hole. Certainly more responsive than before. A few times it felt as if the seconadries were not opening fully. It seemed to make more noise at WOT than before.
Next weekend is a 3 day because of the MLK holiday. Maybe I'll get more time to tinker then.
Thanks for checking in, Greg

 

[Kern Dog]

I have driven the car several times now since getting it back together. For the most part it performs great. ZERO knocking at WOT like I had before. I have yet to dig into the car from the changes I made in late Summer/early Fall last year. Before I made any changes, I figured it would make sense to record my current stats. Today I took the wife along to map the fuel curve while I drove. She read the A/F guage while I drove:

Todays report:

* Idle in Neutral 1100-1200 rpms 13.1 to 13.5
* Idle in Gear 750-800 rpms 17.8 to 18.0 +

* Slow acceleration from 2000-3500 rpms 10,9 to 11.6
* Slow acceleration from 3000-5000 rpms 11.9 to 12.4

* Steady cruise @ 40 mph in OD 12.9 to 13.3
* Steady cruise @ 50 mph in OD 12.0 to 12.5
* Steady cruise @ 60 mph in OD 11.9 to 12.3

* Faster acceleration from 2000-3500 rpms 11.5 to 12.0
* Faster acceleration from 3000-5000 rpms 12.6 to 13.1

* WOT in 2nd gear, 2000-3500 rpms 12.9 to 13.1
* WOT in 2nd gear, 3500-6000 rpms 11.8 to 12.5
* Repeat run 11.6 to 12.1

*********************************************************************

With this info, I see that I need to richen it up a bunch at idle in gear. It stumbled and stalled twice while leaving 2 different stop signs. I suppose that since this occurs at idle and not on the primary circuit, this is a matter of tweaking the idle mixture screws?
I wouldn't think it would need more accelerator pump volume would it?

The "Slow acceleration" between 2000-3500 and 3000 to 5000 showed it to be really rich. This was done at light throttle , I assume entirely on the primary circuit? This makes me think I need to use smaller primary jets.

Steady cruise at 40, 50 and 60 were done in overdrive resulting in a final drive of 3.05 to one. The numbers there are more like what I'm supposed to have at WOT.

The faster acceleration testing showed leaner numbers than the slow acceleration. This was still done without hearing the secondaries open. I'm not sure what to make of that. Maybe I need a power valve that opens sooner there? I have a 3.5 in the carb now.

At WOT it shows that the higher RPMs it goes fatter. I guess that is safer than leaning out.

I welcome any suggestions or comments on my findings.
My gut tells me to adjust the idle mixture screws to obtain a richer in gear reading. It tells me to lean out the jetting front and rear. I'm not sure what to do regarding the Power valve. I'm not sure if I should use a lower rated one than the 3.5 I have.
Please tell me what you think!

 

[Meep-Meep]

What carb do you have? Single plane intake or dual plane? Agreed the idle is way lean in gear and fixing that may be beyond mixture screws. You may need to try a different carb or metering block with larger idle fuel restrictions. Accel pump shot is not the answer here. WOT under load and max RPM should be about 12.5:1 A/F. I don't like the cruise ratio either and that may be a sign you need a different metering block. The emulsion tubes can play a big roll here. The number, size and position of holes will allow the mixture to be fine tuned within different RPM ranges and load characteristics. It's not just about jet sizes and PV's. But before you mess with the emulsion tubes, a smaller carb might help just because you will have a stronger vacuum signal. If you currently have a race Holley that may be at least part of the issue. Carbs like the DP series are really made to perform best under WOT. Not to go around in circles too much, but you also have a big lumpy cam, so you may be stuck with a certain amount of inefficiency. At that point tune for WOT so you don't burn the pistons down, get the idle as best you can and don't let it load up. High overlap has a way of messing up street driving characteristics. Or install a 114 LSA cam and have the tunability you are looking for.

 

[HT413]

What carb do you have? Single plane intake or dual plane? Agreed the idle is way lean in gear and fixing that may be beyond mixture screws. You may need to try a different carb or metering block with larger idle fuel restrictions. Accel pump shot is not the answer here. WOT under load and max RPM should be about 12.5:1 A/F. I don't like the cruise ratio either and that may be a sign you need a different metering block. The emulsion tubes can play a big roll here. The number, size and position of holes will allow the mixture to be fine tuned within different RPM ranges and load characteristics. It's not just about jet sizes and PV's. But before you mess with the emulsion tubes, a smaller carb might help just because you will have a stronger vacuum signal. If you currently have a race Holley that may be at least part of the issue. Carbs like the DP series are really made to perform best under WOT. Not to go around in circles too much, but you also have a big lumpy cam, so you may be stuck with a certain amount of inefficiency. At that point tune for WOT so you don't burn the pistons down, get the idle as best you can and don't let it load up. High overlap has a way of messing up street driving characteristics. Or install a 114 LSA cam and have the tunability you are looking for.

Thanks, meep, that's a lot of carb tuning experience right there.

 

[Kern Dog]

Since it appears that detonation is behind me, I might find that this big cam isn't right for me. I envy the immediate power of a torque rich engine and a moderate stall rated converter. Engines like that seem to give power at just about any point that you want it.

 

[Meep-Meep]

Yep. As I said long ago, use the cubes to your advantage. You can do quite a bit with 500 inches power wise and still drive the car as a daily commuter if you had to. A tight converter will help a lot with drivability and overall efficiency too. You can also power through taller gears and OD, but they better be strong!

- - - Updated - - -

So what did you end up compression wise?

 

[Kern Dog]

To answer a few questions first:
I'm using a dual plane Edelbrock RPM intake and a Grant Demon 850 VS carb. The compression with these head gaskets comes to 10.07 to one.

I found that with the ratio drop, my dynamic ratio dropped off nicely as well. Because of that, I'm curious as to how I'd do with a milder cam and a tighter converter. The 9 3/4 converter I have feels lazy under 3000 rpms where 90% of my street driving is done. Rolling along at 45 or so, ( Any cruise speed really) tipping the throttle to speed up to pass, the tach rises & the engine speeds up without the car reacting as fast as I'd like. If I floor it, it responds but it feels too loose at part throttle.

 

[Meep-Meep]

That's about what I expect out of a 9.5" converter. I'm running a 440 (non stroker) and have a TCI 11" I believe. It's the street Fighter that was available from Summit at the drop of a hat so that's what went in. And I have to say for my mild combo it seems to do very well. Blip the primaries and the tires break loose. You might look into something like that but perhaps not with the big cam. The idea is to have the converter tighten up right around your torque peak, and with a big lumpy cam that comes at a higher RPM. On the flip side my converter in your 500" monster with a low overlap street cam would tend to stall a bit higher. You may very well end up with a stock type converter but beefed up for the power. Focus on 1500 - 5000 RPM grunt and I think you will be a happy camper.

A side note. I am at 10.1:1 CR and 190 PSI. Depending on the carb and intake I can go from no detonation to death rattle. The car ran it's best in death rattle mode but suppressed with race fuel. I have a lot of fuel curve mapping to do but nonetheless I might be at the verge of pump 91. I suggest you stay away from 190 PSI and even suggest 9.5:1 but it might be too late for the latter.

 

[Kern Dog]

What the hell...It has been 4 1/2 years, why not post an update?
To all that looked at your screens and saw a HUGE increase in alerts today, it was because I went back and read this whole 7 page thread just for the sake of nostalgia. I hit the alert buttons too many times to count.I like reading old threads and stuff...It helps show how things have changed over time.
The thicker head gaskets solved my detonation problem, period. No knocks, no pings, even in 100 degree weather. The cranking PSI went from the 191 range down to 165-168 !
I didn't leave the combination alone though. I got tired of the lazy part throttle performance of the big cam and loose converter. It was a great straight line performer at WIDE open throttle, a great burnout setup....but I wanted it to feel more like how a late model performance car feels at part throttle. That meant a smaller, milder cam and a tighter torque converter.
First though, I tried advancing the Lunati cam. I knew from when I degreed it that I had a HUGE amount of piston to valve clearance several degrees before and after TDC so I moved it to a 102 centerline. THis moved the cranking PSI up about 2 points. It idled slightly better, felt a little more responsive but still felt lazy at 40-55 mph in overdrive. I still blamed the converter for most of that but I figured that the cam shared some of the blame.
I switched back to direct drive and sold the Gear Vendors. I had Lenny at Ultimate Converter Concepts build an 11" converter for it and swapped the 3.91 diff for a new 3.55 setup. With this, the car was greatly improved but that rough idle was still bugging me. I swapped in a Mopar 528 solid cam. The idle vacuum nearly doubled. The rough idle and lope was almost totally gone. That was a bit of a bummer, I would have liked to kept a little more lope but sometimes you take what you get. Cranking PSI went to 175, NO knocking and better street manners by a long shot.
I miss the WOT performance of the Lunati sometimes. I still have it stowed away with the lifters kept in the proper order. I don't know if I'll reuse it though since I am adding A/C to the car soon.
Thanks for tuning in, thanks for all the advice. It all worked out though it sure was a long road to get there!