Hey. I have a ’66 Dodge Charger, an all original car except for routine maintenance parts, 86,000 miles. If you were at the 2010 Chrysler Nationals in Carlisle, the car was in the Survivor tent.
My first inquiry, V8 Diet: Big Carbs or Little Carbs?, gives the background for this second inquiry.
The “leaking” 625cfm 4-bbl is still on the engine. I don’t see it leaking; I was told it was leaking by the installer, my car-buddy’s race engine builder. Why he left it on the engine is a concern, especially when he said he put the 750cfm back on the engine. He didn’t. The car is very difficult to start when cold, requiring much gas pedal pumping to get the engine running. The car used to start quite easily after being stored all winter. Let’s assume the 625 is leaking.
But there is, what I think, a greater issue: valve clatter, severe valve clatter; sounds like a diesel engine while running. Here’s what I know . . . when the new timing chain was installed, it was recommended to me to advance the valve timing about 4 degrees, a few degrees for future stretch of the chain, and a few degrees for better performance. I’ve learned that the installer claims he advanced the timing chain 8 degrees. I figure that’s the problem. I can reduce the distributor timing advance and stop most of the valve clatter, but then it’s a pathetic feeble machine. Is the valve timing the problem?
I trusted the advice of a friend, and it just hasn’t worked out too well. Frustrated and occupied more than usual with family care, my Charger sat in the garage all summer, missing the Mopar Nationals in August and Hershey next week. I’m considering having the engine rebuilt, and returned to factory specs. Naturally, the car isn’t going back to the previous mechanic. I’m seeking recommendations for an old school, Mopar-savvy engine builder who will make the engine what it should be and value its historical worth as well. I live in Bridgeport, West Virginia; grew up in western Pennsylvania. Who would you recommend?
You must first define leaking. Is it a bad gasket, bad needle valve or something else? Difficult to start when cold points to a choke problem. The other being hard to start after all winter could be bad gas, due to lack of stabilizer and condensation. You have too many options at this point, how does it start with a shot of starting fluid?
Is this rattle present at an idle and when the engine is not under a load?
If it’s present at an idle also this could be valve clatter. Did this clatter exist before the timing chain swap?
If it did not, and considering the 8 degrees cam timing advance (Ouch) what about the possibility of the intake valve heads tapping the pistons as they come up to TDC?
Unless you have an adjustable cam timing chain setup, it sounds like your installer set the valve timing advanced by one tooth on the cam gear. I can’t say if this is a good thing to do or not but would not be inclined to do as much as 8 degrees.
Thanks, folks. Let me respond to the early round of discussion . . .
waterboy: The leaky carb isn’t the main issue, though it ticks me that it was left on the engine and contributes to the frustration. When this engine is fixed, this carb goes bye-bye. By the way, I’ve loved the original Cougars since the first time I saw one as a kid. Nice ride. Something about hidden headlights just gets me.
Rod Knox: The literature I have shows the 361 having a 9.0 compression ratio. Before the timing chain swap, 93 octane premium was sufficient. The cam timing was changed by the new competition-type adjustable timing chain, another recommendation I agreed to do. Why did I take this car to a race engine builder? Stupid.
ok4450: I don’t hear the valve clatter at idle, and it doesn’t take much load at all to hear the noise. I don’t think we have valves tapping pistons, but I’m not driving it to be careful.
Wha Who? Yep, it is an adjustable timing chain.
I enjoy engine diagnostics as much as anyone, but I’m considering doing a complete rebuild and seeking recommendations for a reputable Mopar engine guy (or gal) that knows and loves these old big blocks, and can make them sing. What say ye?
The FIRST thing I would do is get rid of that 361 motor (basically a truck engine) and drop a 383 4V engine into that car. That’s what makes those cars RUN…The Holly carburetor is prone to leak either externally where you can see it or internally where you can’t…Advancing the valve timing is ASKING for trouble as the intake valves come very close to the head in that engine…Opening the valves early, BTDC, can reduce that clearance to zero…For what purpose?
JMHO, but I’d leave the 361 in there. That’s the motor the car was born with and a survivor car should remain intact. Then again, I’m a purist and like things the way Ma Mopar made them.
Since there is no rattle at idle this sounds like a severe pre-ignition problem and if it’s that bad the engine may not survive much of this.
What would I do? I’d put the cam back on the stock timing marks and keep the distributor timing about 2 degrees advanced at the most.
Many years ago a friend of mine had a '65 Sport Fury with a 361, very mild cam, and a 2-barrel carb on it. We even swapped cars (his Fury for my Roadrunner) on a couple of weekends and I thought the Fury ran very well for a 2-barrel motor. It had no problem boiling the rear tires anyway. Swapped cars twice, got stopped by the cops twice.
You’re running an older car on unleaded gasoline and with no EGR system in place. An operative EGR could help tame any rattling but to do that would require an intake change to an aftermarket w/EGR or a homebrew EGR setup.
Putting the cam back in it’s stock position may even cure or help that rattle or perk the engine back up. (All assuming the engine compression is good, etc)
Granted, I don’t know the particulars of all that has been done or the reasoning but I wonder about the competency of the ones working on the car based on what has been related here anyway.
To quote Jeremy Clarkson from Top Gear, “How hard could it be?”
IMHO, I’d time the engine right and get rid of the supposed 8 deg. of advanced valve timing, then see if the noises go away. If Chrysler thought this was such a hot idea, they would have done this at the factory. If you want to reap benefits from different valve timing, get an aftermarket cam and match it up properly with an intake/carb combination.
I agree with those that suggest getting rid of that 8 degree cam advance and seeing what happens. That’s enough to have the intake valves opening while the exhaust stroke is still in process and the exhaust valves opening while the power stroke is still in process. These could account for the diesel sound, as well as what sounds like valve clatter (but isn’t).
If you’re still hearing a clatter upon acceleration I’d then consider the possibility of pinging, and at that point you’ll need to look at the possibility of the cylinders getting too hot. I’d suspect that with the valve timing set back to spec and the ignition timing at 2 degrees 9as suggested by OK4450) the clattering will disappear. At that point you can try advancing the ignition timing a bit to see what you can get without clatter.
What else has been done to the engine? New heads? Porting? High rise manifold? Anything that might affect comppression?
Hey Caddyman, it’s the numbers matching engine in a survivor car. It has to stay. My thinking has changed from modifying this car to considering buying another for tire-smoking fun and a high “YeeeHaa!” factor at the track.
Nothing else hase been done to the engine, just timing chain and carb. At this point, my thoughts are to put this engine back to spec and just tweak the ignition timing. Perhaps an electronic ignition system that has a subtle appearance, and I need to get a good 2-bbl carb. I like the stock look on this car. It “wows” lots of folk. So many of these cars were cut up and modified, an original example is rare. I’ll try and remember to keep you posted as I go forward.
Still, no recommendations for a savvy Mopar mechanic with a heart for vintage engines . . . looks like I’ll just do the vital stuff myself: change out the carburetor and put the cam timing back to zero. Let’s see how this goes . . .
A couple of things here. The 361 and 383 are essentially the same engine. The 361 has the bore of the old 383 and the stroke of the new one. In 1966, they both used the LB block. If you pull the distributor, you will see LB stamped on the flat surface under the hold down clamp. Actually you don’t have to remove the distributor, just the clamp.
The Charger may be a little different, but in all the other 66 Dodges, the 361 came with a 2 barrel carb only. The 383 came with the 4 barrel. But anyone can take the 383 4v manifold and put it on the 361, or put on an aluminum manifold.
There is no such thing as a variable timing chain. A chain is a chain, but there are indexed timing gears available that are set to RETARD valve timing 2° or 4°. I have never seen a variable timing gear for this engine or seen one that retards 8°. The indexed timing gears are for high performance cams, not stock cams.
Do you have the (very) rare 4 speed or the torqueflight transmission?
I would suggest that you pull the valve covers and determine the source of the valve clatter. You may have worn out lifters. One way to tell is to put your finger on top of each rocker, pushrod end, while the engine is running. It should feel like a cushioned tap. If it hits hard or sharply, then the lifter has collapsed.
With the timing set a stock, you can run on midgrade. In the day, 4° advance on premium fuel yielded the most power and mileage, but that engine was designed to run on regular of the time.
One more thing, if this car was ever in California, make sure that it doesn’t have the vacuum advance disabler on it. It was a required retrofit for awhile until they figured out that it didn’t work.
Thanks for the tips. I’ll check out the lifters after I get the timing back where it should be. Responding to your other discussion . . .
The Charger’s 361 was stock with the 2-bbl only according to the literature I have; the 383 was available with 2 or 4 bbls.
Indexed is the right word, but call it whatever you want, I call it a bad decision for this engine. And I’m certain the cam timing was advanced, at least that’s the word they used.
No, the transmission is the torqueflight; shifts very tight.
The fuel . . . I run premium unleaded in the car, and I don’t mind adding octane boost. May I advance the timing to 4 degrees with today’s gasoline?
The car was purchased new in Pennsylvania, my brother bought it used in 1973. I bought it in 2003 and brought it to West Virginia. The most west this car has been is Beaver, Pennsylvania.
I’ve really enjoyed the feedback on my inquiry. I’ll keep you posted if I remember. Thanks, man.
I’m in agreement with you about advancing the cam timing, especially 8 degrees, being a bad decision.
It’s possible with the cam advanced that much the compression could be way too high due to the intake valves closing sooner.
It would be interesting to run a compression test on this engine and see what the gauge shows.
Low compression generally means engine wear of course but compression can also be too high and this opens up a new can of worms.
My memory is very hazy on this but I think I read of a post a few years back where someone had advanced the cam timing on a Mitsubishi Eclipse and they thought the compression was “normal” (their word, not mine) at 230 PSI on each cylinder.
When pressures get that high even on an aluminum head engine with an EGR system it can be impossible to control engine rattling and the eventual destruction of the motor itself.
You’ve got a great car there and one that is to this day not appreciated as much as they should be. There’s a 66 or 67 Charger sitting in a neighboring town that I’ve been trying to get a line on for quite a while. The car is sitting at an abandoned house with the motor out and on the ground. This one is a 383 car that has been parked since 1980 and the stunning part is that it’s rust free, has an automatic console, factory tach and A/C, and the interior does not have a tear in it. It’s amazing the car has been sitting there for decades without decaying.
I finally tracked the owner’s name down (lives out of state) but so far have not heard anything back.
OK4450, I think we’re all in agreement that the OP’s first step should be to put th ecam timing back to stock. However, I have a theoretical question for you: why would heavily advanced cam timing increase compression?
It would seem to me that the intake valve woud be opening while the piston was still rising in the exhaust stroke, exposing the cylinder to the low manifold pressure as well as the exhaust scavanging at an earlier point. Then by closing earlier it would close while the piston was still trying to draw air in, reducing pressure. It would seem to me that compression would be lower rather than higher.
I know you know engines to a level beyond most, and definitely beyond me. Your comment lost me. What am I missing?
Explaining that is very difficult and space consuming as it leads into cam duration, overlap, and so on along with countless camshaft profiles and how they are affected.
In a very brief nutshell, when the piston starts on the way up on the compression stroke the intake valve is usually not completely closed. Advancing the cam timing means that is is closed and the fuel/air will be squashed a bit more tightly.
The cut and paste below probably articulates this far better than I can and in fewer words.
Advancing the cam timing moves the valve opening and closing events earlier in the cycle. Since the relationship between the intake and exhaust lobes cannot be changed, advancing or retarding a cam affects both the intake and exhaust valve equally. Also, the most important thing advancing or retarding a camshaft affects for engine power is when it closes the intake valve. For example, if the camshaft is advanced, the intake valve closes sooner. This typically increases cranking compression on a high-duration race cam. The result is more torque and power in the lower rpm ranges. But as the rpms increase, the velocity of the air/fuel charge in the intake ports also increases dramatically and the early intake valve closing hurts power
On the other hand, if the camshaft is retarded, the intake valve will close later (usually sometime during the compression stroke). As you might expect, this drops cranking compression and hurts low-rpm power. But as rpm increases and cylinder filling is aided by the extreme velocity of the air/fuel charge in the ports, a retarded camshaft will help power. Usually, the change-either advancing or retarding-should be less than eight degrees. If you need to go more than that you should consider using a different cam
Back to reality, in the case of the OP’s Charger I don’t believe advancing the cam on a 2 barrel motor is going to accomplish much because the rest of the breathing capacity (carburetor throat, cylinder heads, intake manifold, and possibly the exhaust system if it’s a single) are still choking it down in relation to what they’re trying to do.
My hat’s off for having a numbers matching survivor Mopar even if the alternative (a built 440) will make it really scream. I cringe every time I see those over-restored trailer queens being run through the Barrett-Jackson auctions on TV. This is especially true of a straight original car that was gutted and modified, or Resto-modded as they say now. This type of idiocy can also be seen on many of those TV car shows with the now defunct American Hot Rod being one of the worst offenders out there along with Overhaulin’. Those people are a disgrace to the hobby.
Make sure BOTH ignition advance mechanisms (centrifugal and vacuum) are working properly…And set the valve timing where it belongs…
Numbers matching?? What numbers?? What does that mean? About all you can do, with considerable effort, is to determine that the car body and engine block were manufactured during the same model year…
