Hey guys, I need some help with a problem...my 460 pings under acceleration. I'll give you a little bit about the 460...ok, it's a 1977 model, from a Lincoln, with the 95cc chamber heads (D2VE-AA)...it's been rebuilt, 10:1 static compression, reworked heads, not sure what cam, it's fairly healthy, excellent lope, Holley 750cfm model 4150, with MSD ignition and Duraspark II dizzy, it's in a '76 F100 2wd mated to a C6. Uses an aluminum racing radiator, no power steering, just runs alternator and water pump. No headers, had a hard time fitting some so I said "forget it". I have used 92 octane with octane booster, doesn't help, I've retarded the initial timing to 10 degrees BTC, no help. I've unplugged the vacuum advance, seemed to help a bit, but is gutless. It is still running the stock timing curve. When cold, this baby flies, I love it. When it gets to its operating temperature, she is really terrible for pinging if you wanna unwind her...what kind of suggestions for modifications should I attempt (I'm capable of almost anything). I have thought of aluminum heads, but that is a last resort. I thought maybe I need to cool her down more, it runs at about 215 degrees at operating temp. I've heard or been told that maybe rejetting the Holley may help too? What y'all think?

Sorry for the incredibly long post!
Thanks Rad

 

Hi, radramrod2--

There are several different things that could be causing the condition you're describing--indcluding carbon in the combustion chamber that create "hot spots", incorrect "quench" in the combustion chamber, etc.

You said that the engine has 10:1 static compression ratio; what method did you use to calculate this? If you're going by what someone put in a catalog or told you, chances are it's not 10:1.

I would start off by trying a "carbon cleaning" procedure; this will clear any excess carbon out of the combustion chambers that could be causing the "hot spots".

To do this:

1.) Bring the engine up to operating temperature
2.) Remove the air cleaner
3.) Raise the engine speed a bit above idle (maybe to 1500-2000RPM), and start pouring water or transmission fluid down into the carburetor, at a rate that causes the engine to almost die, but keep it running. You can start off with about a quart of water/trans fluid (doesn't matter which kind).
4.) After you have poured about 3/4 of the fluid into the carburetor, speed the engine up a little more and then pour the REST of the fluid into the engine until it dies.

Re-start the engine and run it until all the smoke/steam has stopped coming out of the exhaust system.

This procedure will clean all the carbon off the tops of the pistons and off the surfaces within the combustion chamber; essentially, we know that water doesn't "burn"--it turns to steam, and by following this procedure, you are effectively "steam cleaning" these parts. Using transmission fluid has much the same effect on the parts, but it has detergent in it and since it's a different chemical composition, what it does is soften up the carbon and then the heat and pressure of combustion blasts the carbon off the surfaces.

IF that procedure doesn't fix your issue, chances are the issue is one of too much "quench" space.

"Quench" (sometimes called "squish") is the space between the top of the piston and the bottom of the cylinder head that is OUTSIDE of the combustion chamber, and this space should be NO MORE than about .045"!

Quench is necessary on wedge engines to provide turbulence within the combustion chamber, so that the mixture is fully distributed within the chamber, and to help prevent "hot spots" from forming, and subsequently causing multiple flame fronts from occurring (which is what happens when and engine "pings").

Most likely when the pistons were replaced in the engine, nobody paid any attention to quench dimensions, and that may be what is causing the problems you're seeing right now.

The only way to check this would be to remove the cylinder heads and measure how far below the block the pistons are.

The tops of the pistons should be NO MORE than .005" or so below the deck of the block; if they are, then you will need to have the block decked to return the correct quench dimension to the engine--OR--you MIGHT be able to use thinner head gaskets, depending on how much beyond .005" below the deck they are. Remember--you are shooting for NO MORE than .045" here, and most head gaskets are around .040"-.041" compressed.

 

Alright, so you're saying I need to take the heads off?
I did not build this motor, a machine shop did for another friend, of whom I purchased the truck. Yes, that is what was advertised, I don't believe it to be actually measured. Is there a way to overcome this without tearing the engine completely apart? If so that would be nice! I just spent some hard earned cash on this project and don't really want to pull the entire engine apart. I would be stuck with the motor also, warranty is done for and is only a year old motor. Maybe that's why he sold the trucks

 

Try the carbon cleaning procedures I outlined above FIRST, and if that doesn't cure it, then the next step would be to pull one of the heads off and check the piston top-to-deck clearance.

 

radramrod,
I would say put in a different thermostat first. Lower your operating temp first. You said it goes like mad when it's cold...so keep it cooler. 215 sounds a little warm anyway. I would put in a 160 thermostat and see what happens. Are you running an electric fan? I would also try that to keep it cooler. If it STILL pings after that, then try what Stonecoldtx is suggesting.

 

start with the simple stuff first carbon rarely causes that much pinging, but cleaning it will not hurt, and eliminates that issue, the major cause of pinging is lean condition (too much timing actually causes a lean condition so what exactly do your plugs outer ring look like should have a grey carbon around about 3/4 of the dia min. if not you are definatly running lean, also you could have too hot of plugs in there pretty commen if you used the plugs listed for a 77 check them but I bet you are going to end up atleast 2 heat ranges colder. next yes get a colder thermostat in there 215 is too hot, that engine should be no more than 195, and I would prefer 185, the higher temps were introduced to help with computor controls on newer engines but shortens the life of the entire engine, and they are lucky to have 8.5:1 comp.
if you advertised comp is 10:1, and the piston deck hieght isn't right then yes you won't have a proper quench to help with detonation, but you also won't have 10:1 more likely 9:1, and that should run on 92 + octane bosster without a problem even without proper quench which indicates a tuning problem not a deck hieght problem always start with the cheap, and easy issues first not last.
I just reread your post, you are running D2 cyl heads they are open chamber, and no amount of decking of the block will ever create any quench. if my suggestions don't work then you will need to get different heads go with 73 or later heads as they are closed chamber but still the bigger chamber to keep the compression reasonable.

 

I'm afraid I'm going to have to disagree with you on that one, monsterbaby; carbon is the MAIN cause of "hotspots" on older engines, and when I was working on cars for a living (I changed careers 9 years ago), that was the FIRST thing that we always did, and it usually cured the problem in probably 75%-80% of the cases, if not more. Keep in mind, though, that these were high-mileage engines, and had developed a thick coating of carbon on the tops of the pistons, due to long-term oil consumption issues (burning, not leaking)

I agree with you here--it certainly can't hurt, and probably will eliminate the cause of the ping, if it is indeed caused by carbon.

Although a lean condition can cause ping, its unlikely to be the cause here, because the engine runs fine when it's cold, and if I recall correctly, it only begins to ping when the engine gets "hot" (higher than normal operating temperature). If that's the case, it's more likely that the engine is running a little too RICH, but that can also cause ping, too.

In my nearly 30 years of working, on and around cars, I don't think I've EVER heard that one! I guess you'll have to 'splain how ignition timing has an effect on the air\fuel mixture to me!

Well, I'm gonna have to disagree with you here as well--and the late great Smokey Yunick would disagree with you, too (take a look at his "adiabatic engine" concept--you should be able to find information about it on the web). This is a very common fallacy and misunderstanding about how the combustion process works.

To explain a little better, let me just cover a few physics fundamentals for a minute, and how they apply to internal combustion engines:

1.) An engine is nothing more than an "air pump"; it works by heating air that enters a cylinder and expanding that air. The expanding air creates a high pressure on the top of the piston, and that acts upon the reciprocating assembly by forcing the piston down in the cylinder.

2.) Air expands at a CONSTANT RATE relative to the temperature of that same air; (i.e.: at a given air temperature, there is "x" amount of distance between each air molecule). The more air molecules in a given cubic foot of air (density), the more force it can exert on the piston top when it is heated by the combuston process.

Therefore, if you can maintain air that is much cooler as it enters the cylinders, and if you can maintain the engine as hot as it can possibly be without boiling over, you will create maximum power and the combustion process will be the most efficient.

Thus, 215-degrees is not "too hot" to run an engine, assuming you can isolate the fuel and air from the heat before it goes into the engine.

A good example of this is the fact that diesel engines run MUCH better when they're hot than when they're cold--that's why you see trucks running all the time instead of being shut off.

Well, another point I'm going to have to disagree with, but instead of trying to "re-invent the wheel" by attempting to explain it myself, I'm going to refer you to the KB Pistons website where this article talks about proper quench area:

http://kb-silvolite.com/article.php?action=read&A_id=35

I think the KB Pistons outline why, if this is not carbon creating hotspots, it pretty much has to be a "deck height problem", and is not a "tuning problem".

I agree completely, and that's why I outlined the carbon cleaning process as what he should try first to attempt to alleviate his pinging issue.

As a sidenote, I was fortunate enough to work with the Late Great Smokey Yunick back in the late '70's, when he was evaluating parts for Buick.

A few years later, I joined a division of GM, and worked there for 8 years.

My last job working on cars was as a shop foreman at a Ford dealership, but that was 9 years ago; doesn't mean I haven't kept up with engine fundamentals, theory, engineering and all the OTHER things that make an engine run (and run well!), I just have a new occupation these days.

I also worked with KB Pistons a few years ago to help design the KB 385 piston for a Ford 408 Stroker. I wanted to build a stroker that had a longer piston, both for better oil consumption control and to move the piston pin out of the oil ring land, and that required the use of a shorter connecting rod. I found that they already had a piston that had the right dimensions, but they had discontinued it (it was a 366 c.i. stroker Chevy Smallblock engine design).

I convinced them to re-tool the piston so that it could be used in a 408, and worked with them on some of the details. Two years later, they FINALLY had them completed, but with the new, "stepped dish" piston top design.

Here is a link (again to the KB site) that talks about their "stepped dish" design, and mentions this piston specifically:

http://kb-silvolite.com/article.php?action=read&A_id=37

There is a LOT of good information on that site about pistons, theory, engine design, etc., so it would behoove anyone to visit it and just browse through their articles.

 

well I also worked on vehicles until about 11 yrs ago, I am ASE master auto teck, Chev Certified Journyman, ATRA certified (although that one doesn't apply here) was offered a job teaching at a teck school before I even graduated, and recieved the second highest score ever achieved in that school (would have been the highest but I took off for 3 days when myfuture wife got sick 750 miles away, and ended up in the hospital now shes an ex but thats another story)
Now first thing this engine has been rebuilt, and by that I assume he means recently which means carbon is more likely not the problem,
Next you mention the deck hieght problem and refer to a kb piston web site, but look at his post again, he is using open chamber heads there is NO quench area to be had no matter how much you deck the block, and 9.0:1 piston Will run on 92 octane fuel all day long even without quench
Running the engine with high engine temps does create hot spots (refer to your post on this in relation ship to carbon it also creates hot spots in the heads without carbon) which will cause pinging, and since he is not running an intake that will isolate the intake charge from the heat of the engine, that creates a problem, and the factory began raising engine operating temps to meet epa emissions standard, but heat kills oil thus reducing the life, of both the oil, and the engine plus excessive heat will harden seals etc, etc, etc.
and as far as deisels running better when hot than cold yes upto a point and that bieng about 170deg, and that is NOT the reason they are left running, they are left running because the driver is probably sleeping, and trying to stay comfortable either with heat, or AC, plus a large deisel engine running at 200 deg is probably on ;the verge of melting the turbo, and they also begin to loose power at that temp, my first hand experience with this is I am an over the road truck driver now, that is my new proffession, your suggestions on heat are correct on paper but do not work in reality do to the increased temp of the intake charge which in turn expands the air reducing the amount of air entering the cyl reducing the power (this is why turbo deisels are intercooled to help reduce that them, and inturn make a denser air charge), and when its cold first you probably have the choke on for awhile, but this goes back to my point that you are running it hot reducing the effiecancy (excuse my spelling it's terrible sometimes) of the intake charge.

 

I have read else where that the D2VE head is prone to detonation problems.

http://www.reincarnation-automotive....ns-1-index.htm

 

The above link seems dead. Try: http://www.network54.com/Forum/threa...eid=1093563141 this is a discussion od this head.

 

im having a similar problem just as RadRamRod; i have an 85' F-150 with a
460 (10.5:1 CR) from 71' Lincoln Mark III w/DOVE-C heads, dura spark II ignition, accell super coil, and autolite Platnum Plugs, and C-6 trans w/ stock converter and 3.55 gears. it would ping unbelievably , i called comp cams that recommended initia; timing of 8-12degrees btdc. factory specs for this engine in the car was 6 degrees btdc. i run 93 octane premium and it still pinged one thing i found was that since i have hedders instead of the manifolds the temp gets a little hotter under the hood and with the performance style air cleaner that i had the engine when warm was breathing the hot air . i went back to a factory lincoln style 460 4-v air cleaner and installed the fresh air hose from the air cleaner to the original spot in the core support beside the radiator and its nite and day pinged 50% less, next i disconnected the spark advance . and ran it 30 degrees total , 14degrees intial + 16 centrifugal. made even more difference now i only notice a slight ping accellerating from highway speeds i also running the edelbrock performer rpm intake with 160 stat and edelbock 750 carb, im ondering if the rest of the pinging at mild highway acceleration is due to lean condion because i changed the metering rods ad used the leanest cruise calibration available but 2steps richer on the power calibration , gas mileage is 12mpg city. and also it tends to heat up to the L in normal on the temp gauge when constant speed of 75-80 highway and heats slightly when in traffic for long periods , it has clutch fan from the lincoln , new radiator 2row for 85 F-250 460: 160stat, new temp send unit, 16inch auxillery elect fan mounted on front of a/c condenser set to come on at 210 that tends to hold temp once it goes up and slowly brings it down in traffic or holds it until im moving again. also has fan shroud, new waterpump with backing plate on pump with serpintine belt drive system from 89 460EFI set up .last im wondering if some of the heat is comming from the 355 gears because the engine sounds awfully tight at 75mph till the point i dont like to push it harder. it now has stock tires p235/75/R15! Fellas im thinking of changing the gear , i dont wanna lose the strong take off but want to gain a ore relaxed highway engine in which id dont have to be afraid of going after those sorry chevys on the highway , my choices are :
327:1 (LIncoln MarkVII) fact 3.08, fact 3.00 or 2.73 (police crown vic)

 

Why don't you just install an OD or an OD transmission?

 

beeturbo,
How tall are those tires? I am getting ready to put a 460 in my 53, and then make a trip from Washington state to Florida. I had planned to put 3:55 gears in the rear, but what are you taching out at at 70, and how tall are your tires? I have 33 inch tires.

 

i believe the tires r 29 inch tires, but im stepping down from the 355's its just too much and wit the torque of a 460 u really dont need it , i did some checking and the 69-71 lincoln markIII came out with 2.47 ratio later the 77-79 lincoln
markV came out with 3.00 gear so i'll probably go 3.08 or 3.00the pick up is lighter than a lincoln so it'll still perform.

 

Anyone got that tachometer calculator? I want to keep the RPM's at aropund 2000-2200 with 33 inch tires and a C-6 transmission....what gears do I need?