5 quick operation and Maintenance Qs

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I see you timed the engine at 30 degrees BTDC "under vacuum". Did you not unhook the vacuum advance? The timing when fully mechanically advanced should be 30 degrees at or slightly before 3000 RPM. That means no vacuum advance is hooked up. The vacuum advance should only be hooked up after you determine the mechanical timing is working properly and the engine will perform normally under all loads. Retarded ignition timing will give you problems setting the idle and overheating under a load at "operating" RPM, like on the highway. Also if you did set the timing with no vacuum advance connected did you check that the vacuum advance works properly when applying vacuum with a hand vacuum pump? You may have a vacuum leak in the canister that is leaning out the mixture. Sounds like it is either retarded timing in the cruizing RPM range or a vacuum leak causing a lean condition.
 
Interesting thought - here's what I did, I couldn't tell you if I did it wrong, but - I pulled the distributor apart and tried sucking on the vacuum line attached to see if I could move the plates and nothing happened.

I reattached the vacuum line to the carb and have a counter on a snap-on light that I used to count off degrees advanced. At idle, vac disconnected, and about 700RPM it sits at 8, when I pulled on the throttle, with line attached - I was able to count back from 28-30ish till it hit the mark again.

Is there a better way to set it under idle? When I bought the car, an exhaust valve had burned out, it ran kind of hot, and the timing was 18 degrees advanced, or rather, when you had the timing light on the passenger side, looking at the mark, the light pinged the mark almost parallel to the axles facing the passenger side. Am I reading the marks wrong and I am on the retarded side?

The way I came up with 8 was I searched all over the place and took a general consensus of what was "supposed" to be set to idealy, and 8 came up a lot.
 
Initial timing is not as important as "mechanical" total timing. with the engine at operating temp disconnect the vacuum advance and plug the port/hose. check and write down the timing. then lower the idle to see if it goes any lower and write down the lowest number you get. now slowly bring up the rpm to see when it starts to advance and write down the rpm. continue raising the rpm until the timing stops advancing and write down both the total timing and rpm at which it stopped advancing. If it goes beyond 30 degrees stop and retard the timing some and try again. now you have a picture of you timing curve. you can, if you like, check the timing at 100 or 200 rpm intervals all the way up to your max for a better plot of the curve. what is important is what is your max timing advance at what rpm without the vacuum advance hooked up? then set the top number too 30 degrees at the highest rpm you wrote down. you can now look at your idle timing at the rpm you previously got the lowest timing number. most of the /6 seem to like around 17 degrees at idle. but do not set your timing by that you will need to adjust your mechanical or vacuum advance limits to fine tune everything. Just start by getting total timing with vacuum advance unhooked set at 30 degrees. then drive it with the vacuum still unhooked and plugged. see how that goes.
 
Is your thermostat working? I know you said you just replaced it but one thing I've learned over the years is that you can never trust "new" parts out of the box.

If your thermostat isn't opening up, then you're basically trapping the coolant in the engine and not letting the radiator do it's job. When you threw in your new radiator, you should have filled it up with coolant and then ran it for a while. When the engine reached the operating temperature of the thermostat, did the coolant level in the radiator drop down? You can test your thermostat by placing it in a pot of boiling water to see if it opens.

Did you adjust your valves with the engine running? I know you're getting conflicting answers here but I can tell you first hand that adjusting them with the engine off will only do you a "satisfactory" job. Back in the day my slant needed a valve adjustment and I was too scared to do it with the engine running, so I did it with the engine off the way people were saying and they ended up being too tight. So I did them looser than "stock spec" and STILL they ended up tight. Finally grew some balls and did them the way Dan explained them in this thread and they came out damn near perfect.

http://www.slantsix.org/forum/viewtopic.php?p=72139&highlight=#72139
 
x2 ESP47. running adjustment is the way to go. way easier than u would think.
Did adjustments both ways, and valves were very tight done "Hot not Running", actually had a slightly lopey idle, but never had an over heating issue.
 
Voeltagear, I will have to do as you suggest tomorrow and let you know what numbers I get. I only have a simple timing light with no functions on it and have to borrow the complex one with the RPM indicator and advance light on it from my dad.

As for the thermostat, at 180* on my gauge, I can check and the hose up top is stiff, wheras before that the hose is limp and I can crush on it and it's cold. It may be a thermostat issue as I've seen so many conflicted things about drilling holes in them, not drilling holes in them, ditching them, getting a 160* one, a 195* one, a 180* one and I'm going through everything I have learned so far, because I myself, am stumped. A mechanical friend I went to just told me to swap the radiator, which I did, and after that he shrugged his shoulders and said "I-unno."

I boiled the old thermostat I had, which turned out to work. I've gone through three so far in the time I've owned the car. I'm hoping the one in it now works, since I have drained the coolant about 8 times in the last month to change parts here and there. I even took the thermostat out, before I got a new radiator, and the temperature skyrocketed within minutes, and almost boiled, but I shut her down. I'm worried to try running without one again. Right now the thermostat is 180* and the car runs around town at a constant 180, but goes to 210 on the freeway - and then higher. I know boiling with a 16lb cap is somewhere around 260* or something like that, but I would not like to drop another valve because this.

I'm going to check the timing, and see what I find, and then attack the thermostat and water flow again. I may even be making a zebra of it, and it's going to wind up being something stupid - who knows.

(Zebra: you hear hoofbeats, so you immediately assume it's a zebra, whereas a normal person would say "horse." you complicated it before you started.)

I want to do the adjustment while running thing, but the thought of it is honestly scary. I asked my dad to help me try it initally when the head went back on, but he said quote "that sounds stupid, I've never done that" so... ya know. Dads.
 
Serj22 said:
Voeltagear, I will have to do as you suggest tomorrow and let you know what numbers I get. I only have a simple timing light with no functions on it and have to borrow the complex one with the RPM indicator and advance light on it from my dad.

As for the thermostat, at 180* on my gauge, I can check and the hose up top is stiff, wheras before that the hose is limp and I can crush on it and it's cold. It may be a thermostat issue as I've seen so many conflicted things about drilling holes in them, not drilling holes in them, ditching them, getting a 160* one, a 195* one, a 180* one and I'm going through everything I have learned so far, because I myself, am stumped. A mechanical friend I went to just told me to swap the radiator, which I did, and after that he shrugged his shoulders and said "I-unno."

I boiled the old thermostat I had, which turned out to work. I've gone through three so far in the time I've owned the car. I'm hoping the one in it now works, since I have drained the coolant about 8 times in the last month to change parts here and there. I even took the thermostat out, before I got a new radiator, and the temperature skyrocketed within minutes, and almost boiled, but I shut her down. I'm worried to try running without one again. Right now the thermostat is 180* and the car runs around town at a constant 180, but goes to 210 on the freeway - and then higher. I know boiling with a 16lb cap is somewhere around 260* or something like that, but I would not like to drop another valve because this.

I'm going to check the timing, and see what I find, and then attack the thermostat and water flow again. I may even be making a zebra of it, and it's going to wind up being something stupid - who knows.

(Zebra: you hear hoofbeats, so you immediately assume it's a zebra, whereas a normal person would say "horse." you complicated it before you started.)

I want to do the adjustment while running thing, but the thought of it is honestly scary. I asked my dad to help me try it initally when the head went back on, but he said quote "that sounds stupid, I've never done that" so... ya know. Dads.
Click to expand...

Sounds like your thermostat is fine. Are you sure the cap is fine? Call around and see if any parts stores or shops can test it. It'll take less than a minute to test. That's really weird that your temperature skyrocketed within minutes without the thermostat in. Are you sure your gauge is reading correctly? Seems odd to me.

Trust me, the adjustment while running isn't scary at all. Oil isn't going to be spitting out or anything crazy like that. Just follow Dan's instructions by lowering the idle about as low as it can go while the engine still runs smooth. Then just stick the correct sized feeler gauge in there and feel the rockers chomp down on the gauge. Then place a socket with an extension on the adjuster nut and feel it wiggle back and forth in your hand. Eventually you'll get used to it and you can just cruise up and down the rockers adjusting them fairly quickly. I use Dan's "loose slip" feel when I adjust mine because I'd rather have them slightly loose than tight. I normally go through the valves 3 times because you'll see that once you finish them, you'll go back and check and some will be tighter or looser than you thought. Just remember that you need two different sizes depending on whether you're doing the exhaust or intake valves and that there are two intake valves next to each other in the center...so it's not exactly every other valve.
 
ESP47 said:
Sounds like your thermostat is fine. Are you sure the cap is fine? Call around and see if any parts stores or shops can test it. It'll take less than a minute to test. That's really weird that your temperature skyrocketed within minutes without the thermostat in. Are you sure your gauge is reading correctly? Seems odd to me.
Click to expand...

I wasn't aware anyone tested caps, but I can hunt around. The current cap on it is a vented 16, and is the second one I've bought so far. I guess that doesn't necessarily mean it works. The temperature gauge I had didn't work well, but it could tell when it got hot. With the thermostat in, it gradually climbed to the overheat range, and with it out, I got about 2 minutes of driving in and it shot up there consistantly.

Before I fixed the head, and it was running on 5 cylinders, it did a similar thing, after I fixed the head and it was running on all 6, it overheated faster, and would not cool down. The gasket is on correctly, and there's no blow-by coming from the valve cover. I also cleaned the water outlets on the block before the head went back on.

After I replaced the water pump, the car heated up slower, but would not cool down.

After I flushed the radiator, the car heated up, and cooled down kind of, but not very well.

After I replaced the radiator, the car heated up, and now cools down. It still gets to 210* though, and I feel that's a little much. With the heater on in the car, it sits at about 205 on freeway.

I replaced oil filter, and checked pump - made sure they weren't clogged - no issue there. The carb's been readjusted several times, and no matter how I change the fuel, it seems to be the same. I'm checking timing later today.
 
Ok, so brought it to my dad the other day with his timing light setup. Rechecked and changed timing as you mentioned, voeltagear, and got about 18 at idle pretty consistantly while moving the distributor. (700) I managed to get it to go to 30 around 2700RPM and it did not increase after that. I left the vacuum cap on and drove it. Nothing really changed. Car seems to sit one nick behind 210 on the freeway (maybe 200?), and I never really push it over 3500 on the freeway. But after a bit more driving,m the temp started to accelerate back over 210.
 
3500 RPM is pushing. Now that you know your timing is looking good without the vacuum advance, do you get any more advance with the vacuum hooked up? If not your vacuum diaphragm is done and needs to be replaced. I run around 3K on the highway maybe push to 3200 if I wanna keep up at 80. 3.23 gears in mine. What rear gear are you running? 3.55 I bet. Or your torque converter is slipping. That would cause some heat. Also how is you air cleaner connected. Do you have the stove pipe on that goes to the exhaust heat exchanger? could be getting hot air from the preheater being closed all the time (the little door in the air cleaner inlet). I'm gonna read from the beginning again and see if there is anything I missed.
 
Read the whole thread again. Notes- 1. You "richened the carb a bit", if you are talking about the idle air adjustment screw it does nothing to add fuel in cruise or power mode. Would require jet or metering rod change for that. 2. I need to check on the head pictures, I bought my 76 with the cam bearings in the pan because the oil hole is different on early vs. late heads- hydraulic lifter heads have no oiling hole for the rocker tube (i think). 3. you didn't say if you did a running adjustment on the valves, you gotta try it at least. It's fun, fast, and sure as hell can't hurt your diagnosis. I actually did my very first one outside with a thunderstorm warning in effect and finished before the rain started! 4. Why did it get hot so much faster with the thermostat out? Was that while idling or driving? You are making a crap ton of heat which is caused by Lean A/F (vacuum leak) or retarded timing (which you determined is good), or additional heat from another source (trans cooler maybe). Or the engine is REAL tight or dry (head/cam oiling issue). I imagine if this was the case you would notice a starter working hard to turn it over or some clattering noises.

My brothers car does something similar but it's controllable. Up hill above 80MPH in cruise mode (over 10 inches vacuum) it goes lean and will heat up to about 200 degrees. Adding some throttle cools it, (hard since it will quickly go over 100MPH) or slowing down works too, LOL. He's got some built 360ci Horsepower!

not stumped yet- just putting the pieces together. Do you have more pics of the head and block? Hope I am helping, would love to see you be able to CRUISE at whatever speed/RPM you want without worries sooner rather than later.
 
Voeltagear said:
not stumped yet- just putting the pieces together. Do you have more pics of the head and block? Hope I am helping, would love to see you be able to CRUISE at whatever speed/RPM you want without worries sooner rather than later.
Click to expand...

I appreciate it. I would like to stop looking at the temp gauge with fear myself, considering I drive this car every day.

What kind of pics do you want of the head/block? I'll put up what I have of the head. It has a new set of SOLID lifters in it (not hydraulic) and new rods. One of them broke and another cylinder had the exhaust seat go out, which warranted the head removal and repair.

1. Oh... well, it seems that would be why nothing changed when I set the idle air mix screw... I didn't even think of that. Desperate times I guess.

2. I'll show you all the pics I have of the head off in a moment.

3. I did it with the motor warmed up, set to .10 and .20 respectively by using a dummy dizzy cap with holes in it to check the cam position.

4. I don't know why it heated worse with the thermostat out. I drove it and did not get very far before I had to shut her down. The temperature just would not drop in that case at all. When I set the head back on, I also checked to make sure the pushrods could rotate when they did not have pressure on them, and made sure oil made its way up to the rocker shaft and across each arm to the valves. Also could the transmission be causing the cooler to act up? The old radiator barely functioned, this one keeps a constant temperature at least. But the tranny cooler is brand new as is the rest of the radiator. I don't see how it could effect it as much.

The only issue I really hear is the lifters, which seem like a lot of people just say they are audible, and once the car heats up, you don't hear them anymore. I also have a video of it running before and after to help. Just give me a moment to upload it all. This whole thing has been quite frustrating. It's confused a lot of mechanics I've talked to in person, but to be fair a lot of them are "parts changers".
 
Photos I found that I took:


Re-machined and ready to install head: (dont worry I cleaned the cylinder walls up of all the carbon before I put the head back on. This was just a mental run of all my parts.





Cleaned up camshaft - machine shop said good to use:



When head was busted with a gas soak to find leaks:





Block before cleaning - coolant flew out of those holes in the back willingly when I turned it over, and I cleaned them out just so I wouldn't have to deal with them later.



Once of the pistons in the center (I think it was #3) had a forward mark on it, and I noticed none of the others did. Perhaps it was replaced at one point?





And a video of me and my dad waiting on oil to hit the rocker arms on first startup after the valves were adjusted cold. (later adjusted warm).

[ame]http://youtu.be/Y2eMGlW-Stw[/ame]

He was asking if I had an oil pressure gauge and I told him it was just a dummy light, not numerical.
 
I wonder, is the bottom end hydraulic? (probably not but was wondering) what did the lifter look like? was there a spring clip on top? or just a solid machined piece? my lifters are not audible at all cold or warm with the valve cover on.

I also noticed you have no snorkel so that idea is out, the heads seem to be interchangeable with slight diff but you have spark plug tubes so you have a mechanical head. There is only one way the rocker arm shaft goes on (can physically be put on backwards/upside down) be careful to put the oiling holes in the right place/orientation for the rockers.

One thing I like to do for Fine tuning and finding running/driveability problems is have a vacuum gauge in the car when I drive. See this page for diag with a vacuum gauge. http://www.secondchancegarage.com/public/186.cfm

Is the Exhaust open/free flowing? You checked for vacuum leaks I think, the carb throttle shaft can leak causing lean condition but it would have to be pretty loose. Check the fuel sending unit hose from the tank to Body for collapse/pinch- may be starving the fuel pump. Does your dad have an infrared temp gun- could check temps on the trans cooler lines, exhaust, coolant hoses. See where the heat is coming from to help focus the search.
 
No temp gun. Where would be a good place to get one (cheap)?

The carb I just rebuilt and I checked the throttle blade, no play in the shaft at all really so I doubt it could be leaking that bad on the ends.

I will check the fuel line, I had not thought of that. The float level is adjusted correctly too. I don't know if the fuel filter is a good diagnostic device, but sometimes the whole filter is full of fuel and it's pulling, other times it just a small pool at the bottom pulling up, and sometimes it looks like nothing in there at all. There's a picture of the type of filter i have above. I don't know if that means anything or not.

The lifters look like a candle stick holder, no springs. A large ring on top with a bowl in it, a smaller ring at the waist, and the same size as earlier at the bottom with a slight bevel downward to it where it contacts the cam. The old lifters were pretty worn and the bevel was worn into the lifter (which I was told by the machinist was a bad thing) he replaced them as part of the deal.

Also yes, no snorkel on the cleaner, it is a custom made open element filter I built. It uses some newer chrysler filter that's larger and a cut up version of the "charger 225" cleaner lid.
 
Temp gun is $20 at local hobby shop or walmart, maybe cheaper at Harbour freight. If you could use one and "Confirm" the coolant is too hot, over the thermostat temp at the top hose. I know you have put in a different temp gauge. just a suggestion.

Did you happen to check/verify the oil holes in the rocker assembly when you had the head off? The reason I ask again is the cam lobes and "lifters bevel" get their lubrication from the oil running across the rocker and down the pushrod. And you mentioned the lifters were thought to be worn (with only 80K?). I found a thread on slantsix.org that shows the oil holes and am asking if it is ok to post here.

The fuel gets pretty hot and evaporates in the the fuel filter, haven't had any running issues due to this only heat soak starts that I have to crank to refill the float bowl. most of the time the fuel in mine is at least 3/4 full if not completely full while running. If you look at the filter after shut down you will see the fuel boil! Maybe try to cool the fuel and see if it helps (an ice pack enough run time to test?) I have been meaning to do the fuel line mod that has been posted but it has never been that big of a concern to this point for me.

Again does the timing change when the vacuum is hooked up? Don't know why it would get that hot without working but can't hurt to get it working properly working.
 
Double checked and the vacuum advance is functioning. I went to drop off my kids, and made a cheap mount by duct taping my phone to my leg (perfect I know) just to help get an idea of what's going on on my way home. Naturally I am a terrible movie voice actor, so bear with me. The temp fluctuated from 180 - 210 in the video, and back down. This was only a 15 minute commute from the point where I start the video, to the point I exit. I say "idle around town" a lot, but I just mean driving slow, at low RPM. Not idle...

I will have to get a temp gun from harbor frieght. I was under the impression they'd be more expensive. I don't mind buying my own if they're that cheap. I'm sure I'll get enough use out of it.

I would like to see that photo on the oil issue. I'm not 100% sure on what you mean. I saw oil travel down the top of all the rocker arms, and I am positive it is installed the same way it came out. Some of the bolts were longer than others so I clearly marked it to be sure i had the correct orientation. The rods all coated with oil and the oil seemed to cohere around them and spin.

[ame="http://www.youtube.com/watch?v=EUVhMOup1NY"]1968 Dodge Dart heating issue Slant - YouTube[/ame]

The top dead center section of the water temp gauge is 180. The next dark mark is 210, and then 240, etc...
 
So voeltagar, today I did a more thorough check on timing, because I felt I may have not had it right still.

At 8* at idle, the car would be "all in" at about 30-32 and it didn't seem to go higher. The vacuum was disconnected.

At 18* at idle, the car would be "all in" at 48, and with vac attached, would move to 54 at a high rpm.

I drove it in both cases on the freeway. With the 8, I was able to maintain the 210* temp with a little increase.

At 18, I had a noticable increase in heat (220), but it seemed to drive better.

Tomorrow, I'm purchasing a heat gun and then going to see what happens from there.
 
Yeah 48 is TOO high for mechanical advance. You should be hearing a bit of pre ignition under WOT. Mine likes 28 with regular unleaded. See how much more you get at idle with the vacuum advance connected to the PCV vacuum port. This will give you full vacuum advance so you can see how many degrees it adds. It looks like you only got 6 degrees? Does the can have a hex shape where the vacuum port is? if so it is adjustable.
 
Voeltagear said:
Yeah 48 is TOO high for mechanical advance. You should be hearing a bit of pre ignition under WOT. Mine likes 28 with regular unleaded. See how much more you get at idle with the vacuum advance connected to the PCV vacuum port. This will give you full vacuum advance so you can see how many degrees it adds. It looks like you only got 6 degrees? Does the can have a hex shape where the vacuum port is? if so it is adjustable.
Click to expand...

I didn't hear any pinging at all when it was pulling 48. I had my head in the engine bay pulling on the throttle while my dad held the gun on the other side of the motor, so I would assume I'd hear it, but it wasn't under load either - once I ran it down the street, it was still not audible. I set it back to 8 at idle, and yes, at any point I got 6 degrees of vacuum advance - at least that was the average. The other thing, is the PO (or someone) adjusted the distributor lock to stop at 18 adv idle, and the top is about 5 adv idle. There's no way to retard it on the visible spectrum that's been setup.

What do you mean by "can"? The carbeurator? Or the vacuum attached to the distributor? If the latter, the vacuum diapraghm is round.
 
Yeah the vacuum diaphragm will have a hex shape just behind the vacuum port if it is adjustable. Spark "Knock" will be most noticeable after the curve, meaning when most if not all of the timing is in under WOT and driving. I don't get any until 3500 in second WOT with 30-32 degrees. I also get a very distinct ping that is different when the vacuum advance is too much under light throttle. More like a tapping on the engine block.
 
Idle timing is 8btdc. Got the temp gun. Got as much info from "hot stuff" as I could get I think.

Temperature gauge is reading at 195 in car. Assuming these are all hotter as they are surface temps. Don't know the efficiency of cooling in that thickness of iron.

Top of the head by valve cover 172
Head right next to temp sender 175
Top of radiator 150
Upper Radiator Hose 132
Lower Radiator Hose 110-120
Water Pump body 165
Exhaust Manifold Runners 420-425
Intake Manifold runners 285
Engine Block 180

The thing I think is really odd, is the fuel line (hard part) is 180*, then goes to 250 on the filter, and cools to 150 towards the carb.
 
Well my experience with temp guns has been they are very close to the PCM temp in a OBDII vehicle. I use the Scan tool and a temp gun to verify readings are correct in cases where a fan is not functioning properly or the gauge is reading something other than normal. Your gauge "should" read the same as the thermostat outlet within 1 or 2 degrees. As for the fuel line issue there is a mod posted on this forum to get it away from the exhaust heat and another on building a heat shield for the carb. This isn't a fix for overheating. Compare your thermostat outlet and temp gauge sending unit heat gun reading to your in cabin gauge. if it off by 15-20 degrees then you are only getting to 190-200 on the highway. But you have said it continues to climb over time. in post #69 you said, "With the 8 (degrees timing), I was able to maintain the 210* temp with a little increase" that would put you at exactly 195 degrees. right where your thermostat should operate. If it is still rising beyond that then try dropping to 6 degrees initial. Since you only have 6 degrees vacuum advance you can connect your vacuum advance hose to "manifold" vacuum (tee off of the pcv hose) for 12-14 degrees at idle which will give you a better/cooler idle. When you accelerate vacuum advance drops toward zero so it does not effect acceleration timing advance.

If the temp continues to climb then you are probably running too lean. My slant carb runs on the edge of power enrich and cruise (about 7-8" vacuum) at highway speeds especially if there are elevation changes. On my Carter BBS I cleaned and polished my metering rod and made sure the metering jet had no oxidation/deposits in the bore. I had to use a torch cleaning file to my jet clean. This helped reduce temps in the exhaust and raise my vacuum reading on the highway. Gave me better gas mileage and uphill climbing power.

You are getting closer. Soon you will be able to rest easy knowing that the engine is running beautifully and as cool as it wants to be.

Have you done a running valve adjustment yet. He he...
 
Exactly. It does still climb over time. I have never driven far enough yet to experience what happens after that increase, but am hoping the in-car gauge is wrong. I'll do more tests. I have the timing throttled back to 6 as of before I even read this - I figured it might help. I'll get a T and adapt the vacuum to the PCV line and see what happens. I thought a lot on the carb being an issue. Currently it's the Holley 1920 and I just rebuilt it, but as far as jetting, haven't done anything to it, because frankly I don't know how. I just put the ball bearings where they needed to be, and replaced every part with a new one.

I have a new intake and a carter BBD ready to go, but don't know about the fuel delivery on the new carb either. Maybe someone on here builds or checks them on the cheap?
 
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