More update. I noticed that the idle rpm was not consistent. One time it would rev nicely to 900 with 12 inches of vacuum, the next it woud struggle at 800 or less with 9 inches. Also, one day it would feel that the knock is gone, only to return the next. So, I suspected that the centrifugal advance is sticking. It used to stick a month ago, but I had sprayed it with "liquid wrench" and seemed to get it unstuck. But it was stuck again, the timing was very erratic with rpm.


A brief test however from 4000 to 5000 on second gear (it is about 20 mph/1000 rpm) seems to indicate that the performance is improving. But you can hear the spark knock. In most of this video, the transmission is locked on 2nd gear and accelerating at part load monitoring vacuum. At the higher rpm the knock dissapeared, and you can hear the engine at WOT from about second 51 to 55.

 

Further timing retardation with the current distributor eliminated the knock at the lower rpm as well. I will still need to limit the centrifugal advance for optimum performance, but right now the tming is not the real issue. The real issue is dirt in the carburetor, which I will have to be cleaning up regularly with carb cleaner for the next 100 or 200 miles. (too lazy to clean the tank).


But I will revisit the timing issue soon. I think that the harmonic balancer may not be innacurate after all. If we believe the mark on the H-B, I now have about 12-13 degrees BTDC at about 900 rpm. This will probably grow to about 33-35 at 4000 rpm. Anybody knows what this engine with this camshaft would need to have (again, cam is 224 at .050, 260-280 total, .477-.488 valve lift, 58 overlap. Does anybody know what should I try to shoot for at around 2000, 3000, and 4000 rpm? From what I have read from other sources, modified engines do not need any additional spark advance past 3000, and the max advance is around 35.


Thanks. I am looking forward to testing what I have with the cleaned up carburetor, now that the engine seems to be free from spark knock.

 

Mopar Performance recommends 35 degrees total mechanical advance locked in at 2000 rpm.

 

Haven't seen a 440 with iron heads that could not use 37 to 39 total.

 

Also, the other question would be, what should the timing be at 750 or 1000 rpm? Right now, at about 13, the idle is very slugish, and the vacuum is very low. Of course, part of the problem is a large vacuum leak between the carb and manifold. Apparently, this was what made me think that the centrfugal advance was erratic, the rpm was not constant due to that vacuum leak (I have two gaskets there, and the 4 nuts fairly tight, but the vacuum leak persists). But regardless of the vacuum leak, the engine idled much better and had more vacuum when it was advanced +5 or +10 BTDC from where it is now, and I had about 15 inches of vacuum, despite the vacuum leak (which was apparently there, I just did not know it).


Once I get these issues resolved, I will then work on enriching the carb further, and then replace it with a Q-jet that I got. (I have an 800 cfm AFB, which is maxed out on the jets and the car is still lean at WOT, but still seems to run strong).

 

I gave my spare distributor to the engine builder to recurve it. He apparently has a distributor machine. The springs were very tired and weak, and apparently it would advance fairly rapidly to the max rpm. This is not the distributor that suffered the detonation, but the two units felt similar. This one has also functioning vacuum advance.


Anyway, given that my engine is not too different from the stock HP cam (I have about 0.027 more intake lift and 15 degrees more overlap), and given that the stock HP cam distributor contiunes advancing up to 4000 rpm, and given that in my last test the knck did not go away until around 3500 rpm, I will have th e curve as follows. Full advance (~35?) at 3000. Advance at idle ... 18 degrees? Right now the 12 at idle feels sluggish with poor idle (despite the vacuum leak) and poor response.


Any thoughts?

 

35 degrees total mechanical advance. All in at 2000 rpm. Disregard idle timing!

 

Update.
First, the big problem I had with carbretor clogging and missfiring and backfiring ... turns out the problem was electrical. Crazy, because I definitely had some crud in the fuel, but not enough to make the car run so bad, or even stall, which it did. Turns out that the alternator was over charging, and the ignition system was acting up after it got hot. The points got eroded, and the dwell was down to 25, so even with the new voltage regulator, sometimes acts up just a little bit.


I have the new distributor form the engine builder. This is set up so that at 1900 it gives about 12 additional degrees (from idle) and then another 4 at 3000. Right or wrong, this is it.


But before I replaced the distributor, I wanted to deal with the vacuum leak. So, I took the carb off and filed the base. Most of the vacuum leak is gone (may be all). No lag as accelerating from a stand still. But vacuum is still low. I still have the old distributor (unknown advance, it has worn out springs), but it is now advanced to the point that it barely wants to knock. At light loads up to 2000 it is borderline knock. And I still have only 14-15 inches of vacuum at 900-1000 rpm idle, and about 10 when you put it in D (600 rpm). When driving, a very light hill at about 1500 rpm (speed 40 +) I only have 10 inches. The other way it was about 17 and the car needed no gas to keep on going (high idle).


So, even with the new distributor, I doubt any of this will improve, because I will not be able to advance at low rpm anyway ...


I am thinking that may be there is some carbon build up and the car needs some high speed to clean up? May be more octane boost and some more advanced timing?


Other than that, the engine is smooth, and low rpm response reasonable. A brief WOT test from 2500 - 3200 (borderline knock) felt OK, I am sure the engine would grow at 4000 rpm as did before and pull hard to 5000, but could not test that.


So, carbon build up?

 

In your case...... I would suggest using...Water injection
Just my 2 cents

 

I have heard of using water spray on an idling engine, or revved up engine, to clean up carbon deposits. Could that be what you were suggesting?

 

Try it without the vacuum advance hooked up.....then let us know.

 

No.......
This might help...

https://en.wikipedia.org/wiki/Water_injection_(engine)

 

While the new distributor (not yet installed) has functioning vacuum advance, the current distributor has a hole in the canister, so it is not even connected to the carburetor. I am wondering if it is possible for the canister to vibrate and generate erratic timing, but that sounds unlikely, I have had plenty of 440 distributors with a hole in the canister.

 

I am not sure if this is appropriate for light load. I think this is appropriate for a high compression ratio engine (mine is only 10.5, may be a bit less), or high boost and at high loads, where all the surfaces of the heads and pistons are hot, and no condensation is likely. At light loads where my pinging is occurring, it sounds inappropriate.


May be octane boost. I just need to drive the car more and see what happens. However, the old distributor has to stay on there for now, I think that the more rapid advance of the newer will make things worse and/or force retarded timing at the higher rpm. Some experienced folks I have talked to tell me that deposits cannot form so rapidly (about 1200 miles since the new cam/heads), but may be some high speed driving will help. The engine seems to be running right over 3000 rpm, but I need real estate to run the car there for extended periods.

 

I'm not a fan of vacuum advance distributors on performance builds, I usually disconnect and recurve without. My luck with old distributors, these things are fifty years old, isn't the best without a compleat rebiuld.

 

The new distributor recurve that I described is without vacuum. The vacuum will add to that. In theory, this is good, because it should improve part load gas mileage when cruising, which is what you do most of the time. In practice, given that this engine seems to be knocking at part load, I am not sure how much it will help.


I am still having issues with the ignition. After a brief WOT the ignition acted up again, briefly. I think I should try to file the points with some fine sand paper, may be they are pitted due to the past high voltage they were exposed to, and that's why the dwell is reduced. Eventually, when I figure out the source of the pinging, may be I will install the new distributor.... but for now, I may have to stay with this one. I will take my timing light tonight and see what is the curve on this one, from 1000 to 2500.


Good news is that during the brief WOT, the engine felt very strong in the 3500-4500 range, just like it did about a month ago.

 

I replaced the distributor. Since the advance curve is about the same, the spark knock response was more or less the same, no surprise there. But the old distributor had fried points, which may have been causing some missfire even at the cruising loads, requiring less vacuum for the same load. Also, the vacuum advance seems to be heling. It gives the engine more torque in the 15-10 inch vacuum, so you do not have to load the engine as much.


Even though I did not drive the car much yet, I expect some improvement ... and less fuel consumption.

 

Got the chance to give the car a long 80 mile drive in the hill country. It turned out that I still had pining in the 1500-2000 rpm range at under 8 inches, which unfortunately was hard to avoid due to the terrain and traffic. Once the rpm reached 2500 rpm though (75 mph), you could get over the steepest hills with more than 10 inches, ans no problem there. I wanted to put as high speed on the car as possible to burn up any carbon deposits, if these are indeed the trouble. But I could not run it much more than 3200 or so for any extended period. Part of the problem is the wind noise makes it harder to listen to knock, so I was avoiding any throttle positions that would reduce vacuum below that.


Anyway, on the way back there was less pinging, but that could be due to the possibly higher conentration of octane booster.


I hope that the engine can tolerate part load pinging with minimal risk of holing the pistons.

 

Made some good steps recently. I bought a set of tuning springs for the metering rods, and now the metering rods move towards enrichment at a lower load threshold. I chose the 7 inches, it was probably opening before at 2 or 3 inches. The low load low rpm knock was gone. I advanced a bit and tried again, still gone, only some WOT knock remains. Next step is drill out the secondary jets from .119 to .125. Idle is still sluggish at 10 or 11 once it warms up, less than that cool. I still need to advance a lot more to revive the low speed operation, and I am not sure that this change is enough, but at least it is better than before.


This 800 cfm AFB is clearly inadequate.



Somebody was telling me that premioum fuel down south during the summer is not always as premioum as its supposed to be. You buy 93, but it may be far less. This may be part of the problem, but I never had such problems with the other 440.

 

It has ben a while. Making slow progress, I have had widows when the engine ran great, but have been taking some backward steps too. Much of it is due to me trying to do it on the cheap, too many other projects ...


Anyway, I put new plug wires on the car, hoping to eliminate a WOT miss that has developed. No improvement. I put a new coil, and to my surprise, the part load knock returned. I found a very dark spot last night, and tried to look at my plug wires. It was a christmass tree under there. My mechanic was telling me that probably my spark plugs are deffective, and built up too much resistance (even though only 1500 miles on them). Three plugs that I pulled out at ramdom had a tan coating on one end, and a black on the other (this was not a "plug cut" test after a WOT run, it was a normal plug check after I parked the car and let it cool down). No excess carbon or wetness or any type of deposit build up on the plug. Any comments on the theory?


What spark plugs should I buy for this engine?


Thanks

 

Some bad news on this update.


First, to my surprise, when I advanced the timing to about where it should be, the spark knocked at part load went away. Did this as a test, and worked well. The exhaust valves may have been getting too hot, causing the spark knock. I think I was forced to retard the timing in the past, due to the stupid Aderblock AFB having too heavy springs on the metering rods and delaying the enrichment.


Anyway, but here is the bad news. I isolated the miss on #5, and it turns out there was water in there. My guess is that the mechanic I had working on this 1400 miles (and two years) ago did not torque down the heads properly.


Since the exhaust manifold has been recently removed, I hope that this job will not be extremetly tough. I asked around, and this work may be about $500 at a mechanic. But given my terrible experience with mechanics, I am inclinded to start on this myself. The only tricky part may be the installation of the pushrods. The shop manual is talking about some sort of pushrod alignment.


Any thoughts?

 

I have been trying to remove the exhaust manifold. I got all the bolts/nuts but one. Not the very last, but the one in front. I have been able to loosen it some, but I cannot turn it out. I cannot fit a socket. The short 9/16 socket is too short, and the driver hits the manifold. If I use an extension or a longer socket, there is intereferane with the steering column. The wrench that I had used to loosen has very limited stroke.


Options that I may have is purchase a short wrench, or try a swivel 3/8. What other options do I have? Most of you may be used to headers (which may be even harder, do not know). Having these big engines in smaller cars must be even more difficult than what I am going through! This is not really that much fun!

 

Oh yeah, forgot to mention. At least two of the head bolts were loose. I could tighten them with about 30 ft-lbs. That was probably the reason the gasket failed.

 

Check it all to make sure it all flat.... Hope it's not hurt too bad... Good luck

 

I will check it for flatness.


Now, I am stuck with removing that exhaust manifold. I will try a short 9/16 wrench, a 9/16 wrench with a built-in socket, or a 1/4 drive 9/16 socket. Any other suggestions? Again, the problem with a regular extension on a 3/8 socket is that it hits the steering column, without extension the socket driver hits the exhaust manifold.

 

Use a wrench or a socket to remove the nut's....

 

Thanks RH, that was very useful indeed!


The 1/4 driver did it. Not sure if I will be able to tighten that nut much with the same tool though. You guys using these BB engines on the tiny cars are brave, or ... but let's not get into this


Got the head off last night. There is clear blw through the gasket between 3 and 5. But only 5 had a clean piston. Head looked flat.


But here is the crazy part. That mechanic had promised oversize valves for more power. The valves were identical to stock, 2.08 and 1.74. Looks like I got cheated. The only "out of stock" I have here is the .477-.488, 268-280 cam, so I cannot hope for much more than 380-400 hp ...

 

Where you planing on Hogging out the heads? If not, Me personally... I dont see much gain in that combo... Just my 2 cents

 

That was the plan. To port the heads and install larger valves. We were hoping for something over 400 hp.


I think, as is, I will be in the 375-400 hp.


Anyway, got the head back on last night. I need to check the other head and see if the mechanic failed to tighten that one too.

 

Sounds like the heads got torqued.... It appears to me as if they should have been torqued of a couple heat cycles...