1981 straight six manual 4x4 project

[85lebaront2]

Woah! What a difference a carb can make...

I put on the carb from my 1968 truck and that was definitely the problem, or at least a problem. It idled way lower and the timing was drastically different (over advanced) compared with the old one.

I put the timing light on it and set it to 6* which is what the emissions sticker specified. The truck didn't like 6* very much. I bumped it up to 10* which was the other possible spec listed in the Chilton manual and it liked that much better. I don't know why some got 6* and some got 10* but I'm going with what works.

It still has a brief hesitation when I goose the throttle, but I don't have a vacuum gauge to check the carb ports. I tried a couple different ones with no change. I might try manifold vacuum if I can get the right adapter, but I don't usually drive by stabbing the throttle anyway.

After the carb change and timing, the truck runs smoother, and has way better response especially at higher rpm's.Before it sounded really awful at around 2,500... now it roars over 3,000 with ease and sounds healthy. It feels stronger while driving too, with better torque and pull throughout the rpm range.

After all the funny business I checked the cap and rotor and they were a bit toasted. I swapped in the cap, rotor, and wires from the '68. I checked the plugs also, and they seemed good. All were gapped pretty close to .042 and looked like this:

I traced and fixed a broken wire to the driver side low beam headlight, and pulled the blower motor to look for mouse activity. They have obviously been in there, although there was not much nest evidence. Tomorrow I will open the whole thing up and take care of business.

Because of the issues with the camper it's looking like we will head out Wednesday. I'm glad to have gotten the tune up stuff done though, and I'm hoping for better mpg results.

The speedometer is reading a bit lower than before the bigger tires. It's pretty close up through ~30ish, but 55 on the dial=60. On the odometer 1 mile = 1.165 actual miles. If I'm 16.5% low, I wonder if I could make a metric speedometer read as miles by going ~UP in driven gear tooth count? It might be one way to get it numerically correct even if the units are wrong

The reason for the different timing, manual vs. automatic transmission. A lot of vehicles were that way for years so they wouldn't spark knock if they were lugged down in gear.

[Ford F834]

The reason for the different timing, manual vs. automatic transmission. A lot of vehicles were that way for years so they wouldn't spark knock if they were lugged down in gear.

Thanks. At least I know why it was done, but wow it ran like garbage at 6*. Gary, even though I set it at 10* it was actually sounding better the higher I went (to a point). I might try giving it a little more. I can bring the timing light in case the altitude changes cause knocking but if it is safe to run it that high I will give it a try.

For operation mouse I think I'm going to have to remove the AC condenser and heater cores, blow them out with compressed air and wash them under running water. Then vacuum and wipe out the housing boxes with bleach water. I already washed out the upper ducts but I might do it again just to be thorough. My suspicion is that there is still mouse pee and feces in the fins of the AC and heater cores and that is where most of the smell is coming from. Whatever it is I have to find it. It is disgusting and unsanitary. Hantavirus comes to mind... I will probably get another blower motor to replace the eaten one, but not before the trip. I just don't have time and it seems to be working okay.

Well, I better get back to it, thanks guys for the info and advice! 🙂

[85lebaront2]

The reason for the different timing, manual vs. automatic transmission. A lot of vehicles were that way for years so they wouldn't spark knock if they were lugged down in gear.

Thanks. At least I know why it was done, but wow it ran like garbage at 6*. Gary, even though I set it at 10* it was actually sounding better the higher I went (to a point). I might try giving it a little more. I can bring the timing light in case the altitude changes cause knocking but if it is safe to run it that high I will give it a try.

For operation mouse I think I'm going to have to remove the AC condenser and heater cores, blow them out with compressed air and wash them under running water. Then vacuum and wipe out the housing boxes with bleach water. I already washed out the upper ducts but I might do it again just to be thorough. My suspicion is that there is still mouse pee and feces in the fins of the AC and heater cores and that is where most of the smell is coming from. Whatever it is I have to find it. It is disgusting and unsanitary. Hantavirus comes to mind... I will probably get another blower motor to replace the eaten one, but not before the trip. I just don't have time and it seems to be working okay.

Well, I better get back to it, thanks guys for the info and advice! 🙂

I believe you said it is a 1986 carburetor, does it still have any of the feedback carburetor stuff hooked up and if so is it functional?

Since you have a 1981 truck, it should still be Duraspark and just time it where it runs best.

[Gary Lewis]

The reason for the different timing, manual vs. automatic transmission. A lot of vehicles were that way for years so they wouldn't spark knock if they were lugged down in gear.

Thanks. At least I know why it was done, but wow it ran like garbage at 6*. Gary, even though I set it at 10* it was actually sounding better the higher I went (to a point). I might try giving it a little more. I can bring the timing light in case the altitude changes cause knocking but if it is safe to run it that high I will give it a try.

For operation mouse I think I'm going to have to remove the AC condenser and heater cores, blow them out with compressed air and wash them under running water. Then vacuum and wipe out the housing boxes with bleach water. I already washed out the upper ducts but I might do it again just to be thorough. My suspicion is that there is still mouse pee and feces in the fins of the AC and heater cores and that is where most of the smell is coming from. Whatever it is I have to find it. It is disgusting and unsanitary. Hantavirus comes to mind... I will probably get another blower motor to replace the eaten one, but not before the trip. I just don't have time and it seems to be working okay.

Well, I better get back to it, thanks guys for the info and advice! 🙂

Bill - I think it is a '68 carb.

Jonathan - If it doesn't knock/detonate it'll be safe. And your ears are much younger than mine so you'll probably hear if it pings, which is earlier than true knocking/detonation. But, as you go down in elevation the actual cylinder pressure goes up since there are more air molecules in each intake stroke. And higher cylinder pressure brings in pinging and then detonation earlier.

Here's an interesting read regarding detonation, engine timing, combustion chamber design, etc: http://www.contactmagazine.com/Issue54/EngineBasics.html

As for Operation Mouse, that sounds like a good plan. Somewhere there's residue that is causing the smell, and your plan should solve that problem.

[Ford F834]

Bill - I think it is a '68 carb.

Jonathan - If it doesn't knock/detonate it'll be safe. And your ears are much younger than mine so you'll probably hear if it pings, which is earlier than true knocking/detonation. But, as you go down in elevation the actual cylinder pressure goes up since there are more air molecules in each intake stroke. And higher cylinder pressure brings in pinging and then detonation earlier.

Here's an interesting read regarding detonation, engine timing, combustion chamber design, etc: http://www.contactmagazine.com/Issue54/EngineBasics.html

As for Operation Mouse, that sounds like a good plan. Somewhere there's residue that is causing the smell, and your plan should solve that problem.

Thanks Gary, luckily I still pass my hearing tests with flying colors so I should know if it starts to ping.

The carb is a junkyard take-off of unknown origin. I had to file the holes in the base to make it fit the '68. But it's an early one, no bowl vent...

[Gary Lewis]

Thanks Gary, luckily I still pass my hearing tests with flying colors so I should know if it starts to ping.

The carb is a junkyard take-off of unknown origin. I had to file the holes in the base to make it fit the '68. But it's an early one, no bowl vent...

My ears aren't what they used to be, as Scott is the one that heard Big Blue pinging when we went after Huck. I was able to hear the detonation, just not the pinging. But a slug of 91 octane on top of the 87 helped that a lot.

As for the carb, I didn't realize Carter made a side-draft carb.

[85lebaront2]

My ears aren't what they used to be, as Scott is the one that heard Big Blue pinging when we went after Huck. I was able to hear the detonation, just not the pinging. But a slug of 91 octane on top of the 87 helped that a lot.

As for the carb, I didn't realize Carter made a side-draft carb.

You know how those damn Y series Carters are, can't make up their minds, you have YF, YFA, YH and YS that I know of, maybe they made a YU?

[Ford F834]

My ears aren't what they used to be, as Scott is the one that heard Big Blue pinging when we went after Huck. I was able to hear the detonation, just not the pinging. But a slug of 91 octane on top of the 87 helped that a lot.

As for the carb, I didn't realize Carter made a side-draft carb.

Thanks Gary, my phone app fixes the photo orientation, but assigns the same file name to all saves in the camera roll. When I upload to Nabble it just inserts the first photo with that file name over and over... I need to download more apps and find one that does not do that but I have not gotten around to it. When I shoot pictures specifically for the forum I try to remember to always shoot in landscape so that does not happen 🙄. I know, I know, it's lazy... just like that carburetor.

Operation mouse seems to be a success. Most of the offending material was urine soaked dirt packed into the fins of the AC condenser. Both AC and heater cores were removed, blasted out with compressed air and soaked in 10% bleach water all afternoon. The thick foam on the heat/AC door had to be scraped off. Too gross. I know the thick side was probably put there to insulate the heat from the heater core while using the AC, but it had to go. I can glue more foam there later and/or do the hot water shut off mod if it's a problem. Everything was scrubbed with bleach water and the odor seems to be gone. I get a faint whif here and there (probably from all the foam doors and foam seals in the housings) but I trust it will disappear with use.

I removed the sintered steel exhaust flange gasket and replaced it with a conventional one. I just could not get the steel one to seal correctly.

I emailed David about where he runs his timing, and tried his advice. I believe mine may behave a little differently because I am still running DSII ignition. I tried advancing it from 10* and it did not ping. However, it idled rougher and did not seem as good as it did at 10*. I also tried hooking the distributor to manifold vacuum and that was pretty much disastrous. It ran rough as guts and did not like the extra vacuum at all. Granted, I was not expecting to mirror David's settings as I am at 3,200' elevation and my set up is very different. At the end of the day I couldn't improve upon the results of 10* and Venturi port vacuum advance, so that's what I put it back to. My dad was amazed, he said that was the best running straight six he had ever heard.

The engine is so quiet and smooth that I am now hearing other noises that were masked before. There is still a lifter tick but it seems that it may be getting less. What is more obvious is a knock that sounds exactly like a diesel. This was worrisome at first, but I am 99.99% sure it is the transmission input shaft and associated gear noise. I went under the truck to retighten the exhaust flange after warm up and it was definitely loudest right at the front of the transmission and bellhousing area. As I drive the truck I hear way more gear whine than engine noise. I'm sure it's always been there but I couldn't hear it hooked up to that rowdy diesel. Plus I have no carpet in the '81 so the noise comes right through the tunnel cover. I guess if I'm straining to hear the engine over some subtle gear box noises that is a good thing.

One more day of truck stuff and packing... I'm almost "there". I've practiced my T-case low range shifts and I'm liking the 1-4 Lo then double clutch and continue in 2 Hi. That will get a mountain rolling with no high revving or beating on the clutch. The close ratio trans is going to be awesome for towing!

[Gary Lewis]

Thanks Gary, my phone app fixes the photo orientation, but assigns the same file name to all saves in the camera roll. When I upload to Nabble it just inserts the first photo with that file name over and over... I need to download more apps and find one that does not do that but I have not gotten around to it. When I shoot pictures specifically for the forum I try to remember to always shoot in landscape so that does not happen 🙄. I know, I know, it's lazy... just like that carburetor.

Operation mouse seems to be a success. Most of the offending material was urine soaked dirt packed into the fins of the AC condenser. Both AC and heater cores were removed, blasted out with compressed air and soaked in 10% bleach water all afternoon. The thick foam on the heat/AC door had to be scraped off. Too gross. I know the thick side was probably put there to insulate the heat from the heater core while using the AC, but it had to go. I can glue more foam there later and/or do the hot water shut off mod if it's a problem. Everything was scrubbed with bleach water and the odor seems to be gone. I get a faint whif here and there (probably from all the foam doors and foam seals in the housings) but I trust it will disappear with use.

I removed the sintered steel exhaust flange gasket and replaced it with a conventional one. I just could not get the steel one to seal correctly.

I emailed David about where he runs his timing, and tried his advice. I believe mine may behave a little differently because I am still running DSII ignition. I tried advancing it from 10* and it did not ping. However, it idled rougher and did not seem as good as it did at 10*. I also tried hooking the distributor to manifold vacuum and that was pretty much disastrous. It ran rough as guts and did not like the extra vacuum at all. Granted, I was not expecting to mirror David's settings as I am at 3,200' elevation and my set up is very different. At the end of the day I couldn't improve upon the results of 10* and Venturi port vacuum advance, so that's what I put it back to. My dad was amazed, he said that was the best running straight six he had ever heard.

The engine is so quiet and smooth that I am now hearing other noises that were masked before. There is still a lifter tick but it seems that it may be getting less. What is more obvious is a knock that sounds exactly like a diesel. This was worrisome at first, but I am 99.99% sure it is the transmission input shaft and associated gear noise. I went under the truck to retighten the exhaust flange after warm up and it was definitely loudest right at the front of the transmission and bellhousing area. As I drive the truck I hear way more gear whine than engine noise. I'm sure it's always been there but I couldn't hear it hooked up to that rowdy diesel. Plus I have no carpet in the '81 so the noise comes right through the tunnel cover. I guess if I'm straining to hear the engine over some subtle gear box noises that is a good thing.

One more day of truck stuff and packing... I'm almost "there". I've practiced my T-case low range shifts and I'm liking the 1-4 Lo then double clutch and continue in 2 Hi. That will get a mountain rolling with no high revving or beating on the clutch. The close ratio trans is going to be awesome for towing!

Apps are cheap, but I use Photoshop Express on my phone.

Yikes! That A/C system was GROSS! I'm glad you took everything apart and cleaned it, for your health's sake. And, I'll bet I know how filthy you felt when doing all of that as Huck was also that bad. Just working on him initially would almost cause me to retch.

As for the engine timing, if it works then it must be right. And you can't really use David's numbers as his system is quite different than yours. Different centrifugal advance and different vacuum advance, as well as a different carb that is quite lean, and that makes a difference is how much timing it'll accept. So the only way to tune it is as you've done - play with it until it works best. And, by the way, you really don't know for sure that your timing marks are correct unless you check the damper's mark against TDC. So, you may have more than you think, but what you have works, regardless of what it is. Well done!

On the noise, sometimes the pilot bearing causes noise - either in the pilot bearing itself or, more often, the input bearing on the transmission. A worn pilot bearing allows the input shaft to be positioned slightly differently each time the clutch is used. So if the noise is different after using the clutch then it might be due to a worn pilot bearing/bushing.

And I'm glad you are getting the shift out of low range down. As you said, you should be able to move a mountain, and once you get that mountain rolling the close-ratio tranny will let you keep it moving smoothly.

[Ford F834]

Thanks Gary, my phone app fixes the photo orientation, but assigns the same file name to all saves in the camera roll. When I upload to Nabble it just inserts the first photo with that file name over and over... I need to download more apps and find one that does not do that but I have not gotten around to it. When I shoot pictures specifically for the forum I try to remember to always shoot in landscape so that does not happen 🙄. I know, I know, it's lazy... just like that carburetor.

Operation mouse seems to be a success. Most of the offending material was urine soaked dirt packed into the fins of the AC condenser. Both AC and heater cores were removed, blasted out with compressed air and soaked in 10% bleach water all afternoon. The thick foam on the heat/AC door had to be scraped off. Too gross. I know the thick side was probably put there to insulate the heat from the heater core while using the AC, but it had to go. I can glue more foam there later and/or do the hot water shut off mod if it's a problem. Everything was scrubbed with bleach water and the odor seems to be gone. I get a faint whif here and there (probably from all the foam doors and foam seals in the housings) but I trust it will disappear with use.

I removed the sintered steel exhaust flange gasket and replaced it with a conventional one. I just could not get the steel one to seal correctly.

I emailed David about where he runs his timing, and tried his advice. I believe mine may behave a little differently because I am still running DSII ignition. I tried advancing it from 10* and it did not ping. However, it idled rougher and did not seem as good as it did at 10*. I also tried hooking the distributor to manifold vacuum and that was pretty much disastrous. It ran rough as guts and did not like the extra vacuum at all. Granted, I was not expecting to mirror David's settings as I am at 3,200' elevation and my set up is very different. At the end of the day I couldn't improve upon the results of 10* and Venturi port vacuum advance, so that's what I put it back to. My dad was amazed, he said that was the best running straight six he had ever heard.

The engine is so quiet and smooth that I am now hearing other noises that were masked before. There is still a lifter tick but it seems that it may be getting less. What is more obvious is a knock that sounds exactly like a diesel. This was worrisome at first, but I am 99.99% sure it is the transmission input shaft and associated gear noise. I went under the truck to retighten the exhaust flange after warm up and it was definitely loudest right at the front of the transmission and bellhousing area. As I drive the truck I hear way more gear whine than engine noise. I'm sure it's always been there but I couldn't hear it hooked up to that rowdy diesel. Plus I have no carpet in the '81 so the noise comes right through the tunnel cover. I guess if I'm straining to hear the engine over some subtle gear box noises that is a good thing.

One more day of truck stuff and packing... I'm almost "there". I've practiced my T-case low range shifts and I'm liking the 1-4 Lo then double clutch and continue in 2 Hi. That will get a mountain rolling with no high revving or beating on the clutch. The close ratio trans is going to be awesome for towing!

As most of you probably know, I took the ’81 to Death Valley over the holidays. I pulled our 1960 Streamline travel trailer, then unhitched and did some back country exploring. It was a really neat trip, and I am thinking I will share some of that via an off-topic travelogue thread for those who are interested while keeping the truck related issues here…

 

I wish I could say that my journey was problem-free, but unfortunately I had my share of misadventures.

 

Electrical gremlins. Lots of gremlins. Before I left I had low battery/bad battery symptoms. I had the charging system tested and was told it was all good but the battery was weak. I bought a new one (group 24-F), charged the other one and tossed it in the bed as a “spare”. Glad I did that because after a long trek out to the Racetrack playa my headlights went dim and the engine stalled just seconds after I found a safe place to pull over. New battery was dead as a rock. I put in my spare battery and swapped out the voltage regulator and drove the remaining 57 miles back to camp. The ammeter was acting crazy, showing nothing, then pegging to “C” or the half way hatch to “C” while revving. I’ve never seen more than a twitch out of these gauges.

 

The next day I checked the alternator wiring and the main “batt” lead had crispy insulation, but it was not freshly melted, it had been that way for a while. I didn’t like the look of the wire or terminal so I spliced in a new piece from my toolbox. This seemed to stabilize the gauge, but it still does not seem to charge at idle. After coming to a stop then revving up, the ammeter shows a strong charge. I think the alternator is about done. Mine has a two prong plug-in, but I’m not crazy about the quality of those connectors. I may replace it with one that has regular threaded lugs on the back.

 

Less than 30 miles from home I lost my emergency flashers. Still have flashing turn signals but no emergency flashers. I also lost my brake lights. I was the slowest thing on the road and didn’t use brakes much but obviously that needs fixed. I replaced the high beam foot switch but I was still having my headlights cut out when using the high beams. The tach died before I left, but after messing with the alternator it started working again… about 90% of the time anyway.

 

Besides electrical gremlins my other major issue was engine stalling and cutting out after getting a tank of bad gas in Furnace Creek. After seven more partial fill-ups from other sources it finally went away, but it was quite unnerving especially since I was not 100% sure that it was “just” bad fuel. But I had two spare carburetors with me and 10 gallons of known good gas in cans so I kept going…

 

One morning we were headed to Beaty for fuel and I smelled antifreeze. There must have been a heater core shut off installed at one time that was replaced with a barbed union. A plastic barbed union that decided to collapse. Fortunately the primary hose was long enough to reach the heater core when routed over the air cleaner snorkel. I lost about 2 gallons of coolant but I had spare coolant and water.

 

This hose routing ended up biting me in the behind. On my way home I noticed it wasn’t idling very smooth. By the time I got in to Kingman it was flat out running like crap and would not idle at all. I managed to get it parked out of the way and have a look. The pressure on the snorkel plus LOTS of back road vibration had worked the four screw loose that join the carburetor base plate to the carburetor bowl assembly. It was just wobbling around and creating a colossal vacuum leak. Fortunately it was a pretty easy fix for a guy who brought extra carburetors with extra screws on hand. Still it was no fun at 11pm and 37*F.

 

So now that I got all that nastiness out of the way, let’s talk a little about how it performed. Fuel consumption was not great, but sure could have been worse. After the carb change, just running about empty I was getting 15mpg. I was hoping for better with the 3.00 gears but I never got a “highway” run either. With the (quite heavy) 28’ camper attached it was getting 10mpg under the worst conditions you could throw at it. High winds and steep uphill grades. I was in 2nd and 3rd gear almost the whole way to Flagstaff. Once the terrain became a mix of uphill downhill I was getting 11-12. Note that this was very slow going. The fastest I went with the camper was 55-60mph  on the dead flat. More often I was sub 50mph in 4th, 35-ish in 3rd, and 25-ish in 2nd. The straight six can do it, but it turned the drive to Death Valley into a 2-day event to get there and all day + all night coming home. While in the park, the fuel consumption was still between 11.5-13.5, but a lot of that was slow, rough, steep back roads. For example the Titus Canyon run is 27 miles long but requires 3+ hours. Much of it is best done in low range on the transfer case. I didn’t expect great mpg numbers out of that kind of driving.

 

I will say that the close ratio diesel T19 is an AWESOME gear set to have with the straight six, and an AWESOME gear set to have for backcountry driving. For towing the gear jumps are much kinder than the wide ratio 3 speed + granny models. After all the worry over the start out gear I found that 1st gear starts were fine most of the time. No low range needed unless it was up a hill or I needed more control. 4th to 3rd is seamless. Jump to 2nd left me wishing for a 2.5, but still not bad at all. And for back country, I found myself loving the four close gears while in low range. I thought they would be redundant since they are all so low but they are totally not. You always have the ideal gear for any speed you want to travel based on what the road roughness will allow. I just love it, and it decides my close ratio vs wide ratio dilemma on my diesel build. In the past I always shrugged off the popping out of gear downhill thing. On this trip it drove me nuts. Combined with the rattling noises it is obvious I will either have to rebuild or find another one. It also does not shift as smooth as I remember, but perhaps it does not like the oil I used this time.

 

Brakes. The hydroboost is fantastic, but I am finding out that the pads and shoes get hot pretty easily. There is a 10 mile 9% downgrade into Panamint Springs from the park Even empty (and ~not towing) my brakes were pretty hot by the bottom. Ditto coming back into the park from Emigrant pass down to Stovepipe Wells. My pads and shoes are carbon fiber semi metallic. Maybe there are better ones? I still had stopping power but I definitely smelled them burning and they were fading some. I checked my rear shoe adjustment just to be sure they were not dragging and all was free.

Seats. After spending many long days in the saddle (both interstate and back roads) I have to give the captain chairs two huge thumbs up, and say it is one of the very best things I have done to the truck. The jury is still out on the seat pan mounting system, but if any of you decide to go that way, you will definitely want the 40/20/40 receivers. The Bronco style don't fit right and shove the belt up into your neck.

This update is already too long, so I will leave it at that. Sorry if my spelling is sub par, I am working with a shattered phone screen.