Detonating 493 and what I did to stop it.

[Kern Dog]

Its been awhile since I have posted about this, but I have a few updates to pass along.

I built this 440/493 in 2004. I wanted a fast streetable engine that would run on pump gas. I bought a rotating assembly from an ad in a magazine. The vendor told me that the compression ratio would work with pump gas. I have learned since then that many factors come into play to determine if an engine will run right or knock itself to death.
Over the years I have tried a few things to eliminate the knocking. All the while I have kept the same pistons in the engine.
The specs:
440 block, .030 over 4.35 bore Pistons sit .012 below deck. 4.15 stroke. .039 head gasket thickness, 4.410 bore.
Edelbrock aluminum heads, 84 ccs when new, probably 82 ccs after being resurfaced a few times.
Lunati 316/326 Solid Flat Tappet cam 261* intake, 271* exhaust duration @ .050. .556 lift INT, .578 EXH. Installed at 106.
The calculated compression ratio is 11.04 but when I measured the thickness of the gasket, it measures closer to .035. The .035 number makes the CR 11.14.  This with a quench distance between .047 to .051. The engine would knock at WOT on 91 octane even with total ignition timing limited to 30 degrees.
In 2004 when I first built the engine, I used the Mopar Performance 292/509 cam. I had it installed at 4 degrees advanced and the engine knock was terrible. I had a dyno shop tune the car. They rejetted the carb and recurved the distributor but I would still get detonation.

[Cooter]

I'm convinced with my iron headed 440 @ 10.8:1, that even todays "premium" fuel is just sh*t.
Mine has nowhere near the overlap of your cam but still a bit and it rattles.
Put true 100 octane in tank and no knock.
I even calculated out the .040 'quench' BS...still rattles. Even with aluminum heads, best to play it safe and stick to 10:1 on iron heads, and no more than 10.3:1 or so with aluminim heads.

Newer cars can get away with it due to electronics, but old school motors just can't.

[Kern Dog]

In 2006 I decided to try using a more modern camshaft, so I went with a Comp XE 285 HL. At the same time, I pulled the heads and installed .060 Cometic head gaskets. The engine ran great and didn't knock even with timing advanced to 35 degrees total. That cam went flat within about a month, so I swapped in another. The second cam went flat within the next couple of years. The engine didn't knock but it did start to burn oil and smoke at WOT. I put the 292/509 cam back in. The smoking still annoyed me.  I tried changing PCV valves, intake gaskets and valve stem seals because I suspected that oil was getting into the chambers somehow. I found some wear on the valve stems so I pulled the heads to replace a few valves. I didn't have the money to buy another set of Cometics, so I went back to the Fel Pro .039 gaskets since I had a few pair left over. The smoking was diminished but the knocking came back. This to me was proof that the thicker head gaskets did help stop the knocking.
In the Spring of 2011, I pulled the engine to stop the smoking problem. The machinist found that the rings were heavily worn but that the cylinders cleaned up just by honing. He told me that the knocking was probably from oil burning so I went back with the thin Fel Pro gaskets. I thought that NOW with fresh rings, clean chambers and all, the knocking problems were gone. I was wrong about that.
This year after a 1000 mile road trip, I decided that I had enough of this crap. I started asking around about what to do. Many suggested a change to a cam with a LATER intake closing. Upon the advice of a respected member of another Mopar website, I went with a Lunati solid flat tappet cam. Well, that cam ended up making things worse since it actually increased the cranking compression by an average of 5 lbs per cylinder. At this point, I decided to pull the heads yet again.

[Kern Dog]

The pistons all had crud on them. I suspect oil may have been getting in through the valley pan.

[Kern Dog]

I cleaned the pistons with solvent and looked for signs of detonation. I found no markings of any kind. Each piston looked totally fine without any damage of any kind.

[Kern Dog]

I was told that detonation leaves marks like an ice pick.

[Kern Dog]

Many builders like to talk about how "quench" can allow a high compression engine run on pump premium gas. When I have mentioned that I wanted to go with a thicker head gasket, they advised against it. They felt that I'd lose quench and might still detonate. While I appreciate the advice, I have a hard time believing that if I went with a thinner head gasket to get a better quench distance, I'd be okay with 11.24 compression. I am limited to 91 octane here unless I use race gas. My cranking compression is an average of 191 psi already. A thinner head gasket and higher CR would surely bump me to near 200. Can an engine with that high of a number run on pump gas? I have a hard time believing that.
I ordered a set of .075 Cometic MLS gaskets. Quench be damned, I'm moving forward with the thick gaskets. My ratio will be 10.07 and I'll be able to advance the timing to 35-36 degrees. Many have told me that the gains of running more ignition timing will MORE than make up for the loss of power from losing 9/10ths of a point of compression. Add to this the gain from porting the heads and I should reach to goal I've been reaching for since 2004: A fun, fast, streetable engine.

[deepockets]

wow, that's quite a story. so did you get past the cams going flat? what did you do to make things good there?

[cudaken]

 Red, what is your engine temperature? I have read here on the site that many people think 200 to 210 is OK for a BB Mopar? When I first read that I was going what the %$# are they talking about!   To me anything over 180 it is time to start looking for a places to pull over if I can not speed up. Hotter the car runs the easier it is to knock.

Have you made sure the fuel system is not to lean?

Are you sure the timing ring on the damper has not slipped? You could be running more timing than you think.  

Was the block deck height ever checked? I had one that was -.20 under blue printed deck height.

How much oil is the motor using if any?

My self I would be a little alarmed by the scratches in the last picture of the cylinder walls.

If the motor is running well and not smoking use some octane booster or water injection.

Cuda Ken

[Kern Dog]

The "flat cam" problem could have been a few things. I talked with Dwayne Porter over the Summer. He said that in 2005 or so, a "perfect shitstorm" came about where camshafts were cast with with softer metal, the lifters were being outsourced and built with inferior materials AND the oil companies dropped the levels of ZDDP in the engine oil without telling anyone. These events conspired to deliver the kiss of death to many enthusiasts. He also said while no flat tappet engine was immune, the milder the cam and valve spring, the better chance of survival. Since then, many people have experienced failures like I did.  I thought I did everything right as far as using plenty of cam lube and doing a proper break-in procedure. Both cams had one destroyed lobe. I went back to the Mopar 509 because I kept the lifters in order and I was short on cash.

The engine temperature has always been between 160 and 180. It has never boiled over or felt hot. I've never smelled coolant.
I run an AEM wideband Air-Fuel meter in the car. I jetted and adjusted the Demon 850 carb to run around 13.0 at WOT, 14.0 to 14.8 at idle and at cruise.
I never checked the deck height of the bare block, but I did check the distance of the piston to deck at TDC. Every cylinder checked out at .012 below deck, so the decks are square.
At present, the engine does not smoke at any time. Cranking compression is REALLY even among all cylinders. I read that anything below 10% variation between cylinders is okay for a street engine. My lowest was 185 and my highest was 192. That is a variance of less than 4 %.

[deepockets]

I have on order with Dwayne a solid for my build. went with the nitriding on the cam and edm lifters. i'll be running it on a test stand to break in the cam with just the outer springs. also using joe gibbs breakin oil. if it goes flat, god wanted it to.

[Kern Dog]

Funny... blaming GOD for a cam failure!
I went with Howards EDM lifters with this Lunati cam. I also figured that I need every advantage I can find to avoid another flat tappet failure. If i wipe another one, I'd be an idiot to NO step up to a roller cam.

[cudaken]

The engine temperature has always been between 160 and 180. It has never boiled over or felt hot. I've never smelled coolant.
I run an AEM wideband Air-Fuel meter in the car. I jetted and adjusted the Demon 850 carb to run around 13.0 at WOT, 14.0 to 14.8 at idle and at cruise.
I never checked the deck height of the bare block, but I did check the distance of the piston to deck at TDC. Every cylinder checked out at .012 below deck, so the decks are square.
At present, the engine does not smoke at any time. Cranking compression is REALLY even among all cylinders. I read that anything below 10% variation between cylinders is okay for a street engine. My lowest was 185 and my highest was 192. That is a variance of less than 4 %.

Red, only question I asked you did not answer was if you checked your timing ring.  Never know, it happens.

   Cuda Ken

[Supercharged Riot]

You should look at my build thread
I have pics of pistons that detonated.
Ur engine looks safe for another round
Good luck

[Kern Dog]

Sorry that I forgot to answer about the harmonic dampner. I checked it when I degreed the cam. I was happy to find that the TDC mark was correct.

[warpspeed]

My engine knocked fairly badly when first put on the road ten years ago. 

First thing I did to stop the knock was change to a higher octane which helped eliminate it completely.  So, I thought about what I could do to fix it without the race gas.

I went to 93/94 octane and put an insulator between the carb and intake.  Whow, that was good.  But, not quite enough.  So, I had to go do some more insulation by making sure the gas line isn't touching the engine on the way to the carb.  The hot engine brought up the temperature of the gas to the carb and caused a problem too.

Lastly, I had to take the distributor apart and weld up the weights  to stop the timing from going too high.  That was the final thing I had to do to stop it.  I used our friend Rick Ehrenberg for the help I needed to get that done.  The mopar distributor was over advancing the timing at speed.  It was fairly obvious as I looked at the timing, starting/idle timing all the way up to speed.  The diferential was way too much.

Now, the engine doesn't knock. It runs really hard no matter what the temperature. And my cam is a street/strip cam which is fairly agressive.

One other thing I noticed after taking it down last weekend, is the heat crossovers were not closed off.  Not sure if that would be a problem with a hotter intake and cause the knocking also, but, I don't really like that idea for a street driven car.  My other car with a 340 has them blocked off and that engine doesn't like cold driving temperatures.  (AT ALL!!)

One thing I noticed with my car ititally, is it didn't knock at all before it warmed up.  So, that was how I deduced the need to cool off the gas going into the engine beyond the carb.  Then the timing would never set correctly.  Either the timing was set too low for starting/idle to get the right timing for full advanced or the full advance was too much, which caused the knock, when the start/idle was correct.

[Kern Dog]

Good points, Warp.
The heads I have do not have a heat crossover. I don't drive it in cold or rainy weather anyway. Regarding the distributor, I have made some adjustments to mine in the interest of stopping the knock. It didn't help. I ran some 110 leaded gas and it didn't knock at all. That told me that the detonation wasn't permanent. I didn't want to be obligated to run race fuel at $60 for a 5 gallon jug.

[cudaken]

Red, did you look into water injection? I used it 25 to 30 years ago when I had my 426 Maxie with 12.5 to 1 compression. Sunco was gone so was 102 octane. At one time it was talked about a lot in Hot Rod, Car Craft and other magazines. Here is a link I found.

https://www.youtube.com/watch?v=HkPFZWd8wj4

While the video talks about boost engines, same thing applies with your problem. I am old and live through the time when High Performances Car owners where scrambling for any means to keep there cars on the road.

You have a old problem, so maybe looking at old ways to fix it might help? 

Cuda Ken   

[warpspeed]

Yep, race gas is expensive.  I think I will stick with the low compression engines for fun driving around.  High test is expensive enough.  I want to make  a 383 stroker for my 71 Challenger.  Not sure that will ever come to pass now.  Outside influences are going to stop that for sure now.  Good luck finding an answer.

[Kern Dog]

I have read about water and the water/methanol injection systems. I can't recall if they use a spacer plate under the carb like a nitrous oxide kit. Currently my air cleaner is very close to the hood. I don't have the room for a plate even 1/4" thick!
These head gaskets should make the difference that I need. If it doesn't, something else is very wrong inside....

[SRT-440]

Snow Performance has nice meth/water kit for N/A...and it does use a 1 inch plate under the carb...however, I think I read someone didn't use it and put the nozzles in the  chrome air cleaner lid. Not sure that would work tho.

[cudaken]

Snow Performance has nice meth/water kit for N/A...and it does use a 1 inch plate under the carb...however, I think I read someone didn't use it and put the nozzles in the  chrome air cleaner lid. Not sure that would work tho.

You can plume it into the air cleaner through the bottom plate. Places the nozzle over the carb. That is how I did it back in the day before there where under the carb plates.

Good luck and hope the thicker gaskets does the trick.

Cuda Ken

[Kern Dog]

Things have been so hectic lately with work, long commutes, busy weekends....
Today the boss decide to let us all leave early. I haven't seen my house in the daylight in awhile, so I'm heading out to the shop to begin reassembly!

[Kern Dog]

The heads are on. Headers too.
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!   

Todays work went well. Not too many snags. Spark plugs are not much fun on these cars with headers. That may have been the biggest hurdle. I used NGK plugs this time, 2 steps colder than the Champions I was using before. I set timing to 19 initial and 33 total. I'm sure that I could advance it more. I need to run out the 110 gas and refill the tank with 91 octane. After that I'll reset the timing and consider rejetting the carb to achieve the ideal Air/Fuel readings. The wideband guage should be a big help there.
I have a Rev-n-nator ECU that I'd like to use. I tried it before when I had the 509 cam and nearly 11.0 compression but the engine detonated worse than ever even with timing retarded as per their instructions. I like the idea of having a rev limiter.