changed plugs and working much better

I took the d-21 plugs out this morning and put it autolite 386 plugs. The difference is like night and day! I plowed 4 more acres and the tractor is running fine. It recovers well when it bogs down and when I pull the TA lever it recovers right away and smoothly. With the d-21 plugs it had difficult recovering when I pushed the clutch in.

I am a little worried that I might have damaged the engine with the d-21 plugs. Two of the plugs that I took out were discolored on the outside of the steel hex portion.

I think it is a little irresponsible for the Case-IH dealer to sell plugs that are too hot for the tractor. When I bought those plugs I told them that those were different than what they sold me the time before, but they assured me those were the correct plugs. What do you guys think?

Also, if less than 93 octane gas is damaging to the engine, that I have probably done some real damage to that engine. I have put about 500 hours on it with 89 octane gas. How can I tell if and how much damage I have done?

its not there fault , as there is different heat ranges for the application. you probably did not mention tractor usage. those are ok for light duty work or stop and starts. for regular field work he should have gave you D16's. he also should have known, but lots of these partsmen are not familiar with the older stuff and dont know themselves.
tractor vet is the gasoline guru.

Cousin has run a 656 for years on 89 octane but not doing heavy field work. You were smart to stop lugging it when it was not running right. It's an old plow tractor and pretty tough. If it's not missing, smoking, or using much oil you most likely have not hurt it

Ya should have been with me yesterday , I was on a 706 gasser that i sold to a close friend some twenty plus years ago and just did a major on the engine this spring.I spent about 12 hours on it pulling silage wagons with it , these are 18 foot H/S rear unload we were filling them to the roof and probable weighing in at around 28-30000 lbs . Our ground over here has shell we say a roll to it and some of them little humps and bumps are STEEP . It was working the 706 big time and it would pull down to 1000-1200 RPM in second high with a good run on the hills . 13000lb. tractor with 28-30000 behind ya on a hill ya had best pick a gear that will carry ya over the top with out pulling the T/A as if ya do you will spin out and then you can not hold the load on the hill and things get ugly real fast . she was a pawen each load up the hills at times she was getting a little light in the ft. end . Normally we do not use the 706's to pull these wagons but the rest of the fleet were doing other stuff .

I have some hard plowing spots in my field. Those spots will pull my 656 down to 1000-1200 rpms when in 2nd gear,also. I am using a trailer plow, 3-14's, and plowing 8 to 10 inches deep. When it pulls down to 1,000 rpm I pull the TA.

If ya have three point on that tractor myself i would be looking for a nice set of 540 semi mounts , you would be pleased with the way it would handle them . while working ground i would be pulling the T/A a little higher like 14-1500 . I was dragging the 706 down that far so i would not break traction . It is no fun tryen to keep a silage wagon straight backwards when it is dragging ya back down a hill.

Used ta pull hay wagons a lot with uncle Mike's 706. If the elders caught you with the torque back all three of them dad, uncle, Grandpa would line up to kick your behind. That thing will coast the torque is for plowing they would yell. Don't understand why you're using 2nd hi, just too handy to shift into low and pull up to the unload real easy and safe, same for reverse doesn't back up 10 MPH like 4th. Have fun and stay safe out there.

Running a plug that is too hot for the engine/conditions will damage the plug but not so much the engine. Thr hotter plug has less insulation, therefore the electrode runs at a higher temp, (to burn off deposits)
The entire plug may run a little hotter also, but this has very little effect on combustion chamber temp, as it must all be transferred via the mass in the cyl head. Negligible cht change noted at the piston dome, as the combustion is at the same time, and same place as a cooler plug.
89 octane is higher than 99% of the farmers used in 1946.

Running too hot a plug can very easily damage an engine. The hotter heat range plug will have a center electrode that runs at a higher temperature than a colder heat range plug. When that temperature gets too high it starts to cause preignition in the engine as the hot electrode ignites the fuel before the spark occurs. This has the same affect as advancing the ignition timing. If you look at the original post this is what was causing the problem with his engine with the D21 plugs. The engine could not recover the RPMs even when the load was removed because in effect the timing was way too early. Ideally ignition should occur only far enough before TDC that the burn is complete by 10° - 20° ATDC. Preignition may cause the entire fuel load to be burned before the piston reaches TDC.

This condition can cause holes to be burned through the center of the piston is some engines. In the IH engines the piston tops are thick enough, though sometimes you will see damage in the center of the piston, that the result is more likely to be scoring as the pistons overheat and expand from the early ignition. You will sometimes also find broken rings and ring lands although that condition is more apt to be caused by detonation.

Detonation is the result of combustion starting at two or more different locations in the combustion chamber. It usually is the result of too low of an octane fuel for the engine as that will allow spontaneous combustion to start elsewhere in the cylinder after the spark has begun ignition. This may also be caused by preignition because the early ignition causes increased pressure in the combustion chamber which increases the possibility of spontaneous combustion. It may also be caused by glowing carbon deposits in the cylinder. The ping you may hear is the two flame fronts colliding.

It has the 2 pt. fast hitch.

Thanks! I feel a lot better now!

The tractor is not missing, smoking, and is not using a lot of oil, so hopefully I am ok.

Ok so ya can get the straight prong and still use a 540 semi mount . I had my first set behind a Farmall 450 D with fast hitch and i could pull 4 just as easy as the 311' that i first bought.

... vet is right... in [u:d65664ad00]most[/u:d65664ad00] cases, a semi- or fully mounted plow will pull easier than a pull type. Load transfer is just better on [u:d65664ad00]most[/u:d65664ad00] tractor/plow set-ups, and with a good draft control system, it gets even better. I highlight [u:d65664ad00]most[/u:d65664ad00] because there are going to be exceptions to [u:d65664ad00]almost[/u:d65664ad00] every rule.

Very good explanation of what takes place in
combustion process. Far as D-21, they are a very
good plug BUT, only for light piddly type work.

Well, that is sure testing the overload torque I quess and not saying much for the five mph farming these tractors were designed for. ( I didn't design them , just work on them).

(quoted from post at 23:52:26 10/09/11) The ping you may hear is the two flame fronts colliding.

Click to expand...

Well, that part is a no. Metals ping, gas fronts do not. Pressure wave loads up the piston surface real heavy, and then pressure drops off and the piston rebounds at some point. A lot of parts are really upset about that time.

(quoted from post at 19:21:53 10/10/11)

(quoted from post at 23:52:26 10/09/11) The ping you may hear is the two flame fronts colliding.

Click to expand...

Well, that part is a no. Metals ping, gas fronts do not. Pressure wave loads up the piston surface real heavy, and then pressure drops off and the piston rebounds at some point. A lot of parts are really upset about that time.

Click to expand...

That part I would say is garbage in - garbage out. I have had instructors from several different sources, both propane and gasoline, give that explanation, none of which I felt gave a good reason for the cause of the pinging noise.

Kinda funny but I was raised on Champion plugs. Dad always preached to me that I should always use em. 1st time I had a problem was in 75. Did a tune up, drove 650 miles and had several misses at idle and fuel econemy was off. Took the plugs in and put em on a tester and had 3 bad plugs. But dad was a God to me and I still used em. Was home on leave and dads AC CA that ate plugs, 2 to 3 sets a year had a valve problem. So while dad was doing field work with the other tractor I pulled the head and took it in. Couple of days later I picked it and decided that when I put it back on I'd put new plugs in. The place I went didn't have the Champion plugs for so I got AC's. About 6 months later I was back home heading to Germany and and told me "that valve job fixed my plug problem"! I told him "dad I don't know, I put AC's in when I put the head back on". He got mad, went to town and got his Champions. About 2 months later he sent me a letter in Germany telling me how the Champions had failed again and he put the AC's back in and it was running fine. I still used Champions....until I bought a Bobcat with and Onan engine. That thing ate plugs every 20 hours. Well the engine was weak and I thought it was the engine. Did a complete rebuild and still every 20 hours it ate the plugs. I decided to try a different plug......fixed that problem right now! I don't use Champs any longer!

Rick

The trailer plow does a good job of plowing. Very even and level. Just pulls hard, I think. I remember my uncle pulling the same plow with an M. My Dad borrowed the tractor and plow once and pulled the plow in 3rd gear! Now, I don't see how that was possible!

You were on some very flat land. At best you will get 10 ton of corn silage in a wagon with no roof and filled with a self propelled chopper. If you were hauling haylage your numbers are way off.