The real JD 4520: Compression Issues

[Tx Jim]

Coyote Flats does not get cold . The place is however on my to do list to visit . https://www.timeanddate.com/weather/@5340338/climate

10°F a few nights ago is TOO COLD for my old bones!!!!!!!!

 

[Tx Jim]

Those 55 series were about the best a man could get back then. Most of the bugs were long worked out when those came.
That would have the 7.6 in it IIRC.
Does it rattle when ya shut it off, the last few turns like a tin can full of marbles?

No it doesn't rattle when engine is stopped.

 

[rockcreek4630]

If I am understanding you have not run this to even seat the rings since the high compression kit was installed if so that will change your compression readings some. Next if it starts better with a full tank of fuel it needs a check valve installed. The old joke with them tractors was there is a reason the parts department sells either by the case and not the can.

 

[used red MN]

While both the 4520 and the 44/4630 unitizes the same 6404T engine, the do call out different piston assemblies. The 4320, 4520, and 4620 all uses the same piston kit. The 4430 / 4630 do not share the same part number. What is the difference between the two, I will probably never know.

I installed a new Reliance high compression in-frame kit in my 4020 (1965 build year) a few years ago. When I did a compression test prior to tear down the compression was at 320PSI. Per my 4020-tech manual, compression should be between 450 - 475. I did not do a compression test afterwards, but she will start on a 20-degree day with no heat and hardly a misfire / white smoke.

I don’t see where you have said you have had the pump and injectors checked by a diesel shop?? If it is here somewhere I missed it, sorry in advance.
Since the cam is an unknown I would suggest checking it against the lift specs.
After that it leaves you to pulling the head and checking the cc’s of the combustion bowls in those Reliance “HC” pistons against a stock Deere piston. An old farmer I worked for a while had a 4520, it was summer in Kansas so anywhere between 70F and 100F we never had to use ether to start it. Of course I can’t guarantee it had the original engine almost everything he had was “tinkered with” like the 4020 that had extra cowling added by the dash to make up for the extra length of the engine in it that came out of some combine.

 

[brendonh]

The old joke with them tractors was there is a reason the parts department sells either by the case and not the can.

LOL!!! Yep!
Add to that, they sell you a case of john deere premium 80% ether. Not that 25-40% wimpy stuff that ya get from everyone else. It takes real ether and lots of it to make a Deere do anything!

 

[used red MN]

LOL!!! Yep!
Add to that, they sell you a case of john deere premium 80% ether. Not that 25-40% wimpy stuff that ya get from everyone else. It takes real ether and lots of it to make a Deere do anything!

The 40 series and up were not that bad. Most of the 30 series were not terrible if you kept good batteries and starters on them.

 

[brendonh]

The 40 series and up were not that bad. Most of the 30 series were not terrible if you kept good batteries and starters on them.

Our 4630 was reasonable. The 4640, we didn't use it much in the winter at all. The few times we needed it, just plugging it in was good enough. The 30 needed some sniff and the battery charger on any day less than 30* The day in January, the 30 is out at Grandpas, not plugged in, sitting on the auger, all ready do haul wheat in a couple weeks....the blizzard hits, no way to clean the snow off in town where we lived, so out to the farm we go, it's 5 below, wind blowing, fuel gelled up, took 5 hours a weed burner, 6 cans of ether, 2 cans of fuel thaw, and a set of fuel filters go get that thing running that day.

 

[used red MN]

Our 4630 was reasonable. The 4640, we didn't use it much in the winter at all. The few times we needed it, just plugging it in was good enough. The 30 needed some sniff and the battery charger on any day less than 30* The day in January, the 30 is out at Grandpas, not plugged in, sitting on the auger, all ready do haul wheat in a couple weeks....the blizzard hits, no way to clean the snow off in town where we lived, so out to the farm we go, it's 5 below, wind blowing, fuel gelled up, took 5 hours a weed burner, 6 cans of ether, 2 cans of fuel thaw, and a set of fuel filters go get that thing running that day.

Sounds like poor preparation to me, I also know “stuff” happens.

 

[brendonh]

Sounds like poor preparation to me, I also know “stuff” happens.

Oh it was for sure.
We were prepared to haul wheat from our bins to the elevator. We were not prepared for a blizzard to dump 20 inches with a 30mph wind. We knew about the storm, we knew about the wind. We expected, cause the forecast said, we were not getting the 20 inches, rather only trace to 2". Don't need snow removal equipment for that.... Well the storm wobbled, and we caught the punch in the teeth. Power outages, no way to move anything in town. The E-Z On loader only fits the 4630, so it's the one, and its on the tractor, but that is 4 miles north of town and not ready for anything on a -5 to 0* day like that day.... So yea, that poor thing was not setup in anyway for starting and moving in 0 degree weather. It was supposed to only have to run next week, when it was highs in the 40's, bright and sunshiny type day... I don't even think we had winter fuel in it. We had the poor starter so hot, I was shoveling grain scoops full of snow on it. She just sizzled and steamed that stuff of as fast as i could shovel it on.

 

[Hay maker2]

Yea,

I'd expect the 4020 to start better. They always have. Higher Compression. Cause.....no turbo.
That was the very gripe everyone had about Deere engines when they put turbos on them.....they won't start anymore.

Deck the head, put the high compression pistons in it, basically make it a 4020 again, and poof.....it'll start.

Oh, Buick, you can do that, and the head gasket will blow. Every time. (well it might not today, cause the gasket is modern, but in 1975, it didn't) It is the very reason Deere lowered compression. In fact, Deere struggled for 8 years on how to make a 404 and a 466 head gasket not leak. 6 or 7 different gaskets, 5 different bolt types, washers, no washers, Special, hi grade, low grade, 5 or 6 different DTAC solutions, torque the head this way, no that don't work, do it that way, retorque after hot, no don't retorque after hot, use these bolts and this gasket, blah blah blah..... for 8 years..... cause the head gasket leaked........ cause: too much turbo....so sayeth Deere anyway....

The solution finally came in for all 466 engines with the adoption of the 6076 way of doing things. I nice rubber coated, steel fire rings and silicone water rings, along with another new torque pattern.......torque turn method eh...hummm.. and new bolts.......again.......flanged this time.

Finally, fixed!! No more blown head gaskets! Well, it took longer to leak oil around number 6 this now anyway. I remember the first time I did this, I thought for sure I was going to bust the bolt with the breaker bar and fall off the ladder doing the last 90* turn.


Oh, it didn't help that a 4630, ours included, were usually turned up from 160hp to somewhere around 185 to 210. In fact, that might be the sole reason 404's and 466's couldn't keep their heads, but...Deere saw enough of it to go through a crap ton of work to stop the head gasket leaking...

Anyway, for this issue......personally. I wouldn't chase compression anymore. I'd chase starting.

Destroker kit, make sure it works and/or it's installed.
Replace or rebuild the injectors. Make them pop at 3800psi again, and have good nozzles in them. No streamers
Advance the timing by about 3 degrees on the pump. It'll start better, just know the limit is egt under max load fuel delivery cause of the turbo.
Overhaul the pump, it's gotta be almost perfect for your best chance at starting.
Biggest CCA batteries you can fit, use 00 cable size. Ground the battery to the starter bolt.
Overhaul the starter or use a nippondenso version, it'll have the gear reduction in it.
Ideally, the starter will crank that engine at nearly 300 to 500 rpm. This will make it start.
Oh, use full throttle, every time, just back it off when it starts hitting on all six smoothly and the tach is north of 1200 rpm

Anyway, my buck fifty on the matter and some stories from an old western kansas deere mechanic......i miss those days....working on those was fun.

All my John Deeres that have the closed center system has an electric destroker installed. The cost of this is cheaper than beating and replacing batteries. Pic of the destoke kit on my 4520 in question

 

[Hay maker2]

I don’t see where you have said you have had the pump and injectors checked by a diesel shop?? If it is here somewhere I missed it, sorry in advance.
Since the cam is an unknown I would suggest checking it against the lift specs.
After that it leaves you to pulling the head and checking the cc’s of the combustion bowls in those Reliance “HC” pistons against a stock Deere piston. An old farmer I worked for a while had a 4520, it was summer in Kansas so anywhere between 70F and 100F we never had to use ether to start it. Of course I can’t guarantee it had the original engine almost everything he had was “tinkered with” like the 4020 that had extra cowling added by the dash to make up for the extra length of the engine in it that came out of some combine.

Old injectors were tested. Some were not where they belong. Replaced with 6 new Deere pencil injectors.
As for the injection pump, this has not been rebuilt. I have been in contact with my pump guy that has rebuilt many pumps for me, and he does not feel there is a pump issue. His assessment does not rule it out, before I'm done I'm for sure it will be rebuilt.

 

[used red MN]

Old injectors were tested. Some were not where they belong. Replaced with 6 new Deere pencil injectors.
As for the injection pump, this has not been rebuilt. I have been in contact with my pump guy that has rebuilt many pumps for me, and he does not feel there is a pump issue. His assessment does not rule it out, before I'm done I'm for sure it will be rebuilt.

In my opinion this is probably the smoking gun. Are you telling your pump guy the compression doesn’t make spec? If so I would bet his answer is based on this. Sounds to me per other discussion on here the compression spec may be a “pie in the sky” number. I wonder if member @tim s would know what number a compression test on one of these after a rebuilt should show.

 

[Hay maker2]

Yea,

I'd expect the 4020 to start better. They always have. Higher Compression. Cause.....no turbo.
That was the very gripe everyone had about Deere engines when they put turbos on them.....they won't start anymore.

Deck the head, put the high compression pistons in it, basically make it a 4020 again, and poof.....it'll start.

Oh, Buick, you can do that, and the head gasket will blow. Every time. (well it might not today, cause the gasket is modern, but in 1975, it didn't) It is the very reason Deere lowered compression. In fact, Deere struggled for 8 years on how to make a 404 and a 466 head gasket not leak. 6 or 7 different gaskets, 5 different bolt types, washers, no washers, Special, hi grade, low grade, 5 or 6 different DTAC solutions, torque the head this way, no that don't work, do it that way, retorque after hot, no don't retorque after hot, use these bolts and this gasket, blah blah blah..... for 8 years..... cause the head gasket leaked........ cause: too much turbo....so sayeth Deere anyway....

The solution finally came in for all 466 engines with the adoption of the 6076 way of doing things. I nice rubber coated, steel fire rings and silicone water rings, along with another new torque pattern.......torque turn method eh...hummm.. and new bolts.......again.......flanged this time.

Finally, fixed!! No more blown head gaskets! Well, it took longer to leak oil around number 6 this now anyway. I remember the first time I did this, I thought for sure I was going to bust the bolt with the breaker bar and fall off the ladder doing the last 90* turn.


Oh, it didn't help that a 4630, ours included, were usually turned up from 160hp to somewhere around 185 to 210. In fact, that might be the sole reason 404's and 466's couldn't keep their heads, but...Deere saw enough of it to go through a crap ton of work to stop the head gasket leaking...

Anyway, for this issue......personally. I wouldn't chase compression anymore. I'd chase starting.

Destroker kit, make sure it works and/or it's installed.
Replace or rebuild the injectors. Make them pop at 3800psi again, and have good nozzles in them. No streamers
Advance the timing by about 3 degrees on the pump. It'll start better, just know the limit is egt under max load fuel delivery cause of the turbo.
Overhaul the pump, it's gotta be almost perfect for your best chance at starting.
Biggest CCA batteries you can fit, use 00 cable size. Ground the battery to the starter bolt.
Overhaul the starter or use a nippondenso version, it'll have the gear reduction in it.
Ideally, the starter will crank that engine at nearly 300 to 500 rpm. This will make it start.
Oh, use full throttle, every time, just back it off when it starts hitting on all six smoothly and the tach is north of 1200 rpm

Anyway, my buck fifty on the matter and some stories from an old western kansas deere mechanic......i miss those days....working on those was fun.

Tractor has two group 31 1050 CCA batteries, new 2/0 cables, cleaned mating surfaces as well as starter to case surface are all cleaned. Yes, I can attach the ground cable directly to the starter, I have done this in the past. I firmly believe in the in-line Nippendenso starters.

Several years ago, I did a starter comparison and measured actual cranking RPM's. I tested the Delco, Denso, and a gear reduction starter on my 4020. The Denso spun the tractor over the fastest and the gear reduction was the slowest. I posted all the results on YT and encourage people to look it up.
I'm also waiting for all of the response from the people who swear by the gear reduction starters but never did any actual testing to prove it out. Yes, the little starter MOTORS (not to be confused with start drive) scream when cranking, but all of them extra RPM's are greatly reduced in the gear reduction of the starter prior to the starter drive engaging into the fly wheel.

 

[Hay maker2]

Update: After reading though these post as well as sifting through my 4430 manuals I came to the conclusion that maybe in fact that the compression listed in the 4520-tech manual was wrong. At the same time, I check everything again, checked the valve lift which per the manual was within specification and still the 300PSI compression level.

At this point I adjusted the exhaust valve clearance from 0.020” to 0.028” as per the 4430 manuals so see if this would increase compression. When I did this, I left the compression tester installed and when I was turning the engine over by hand I could hear blow by. I sprayed soapy water around the compression tester, and it was not sealing in the head. I sprayed it again and spun it over with the starter and the blow by was incredibly, I still managed to get 300PSI on the tester. In repeated this with a second compression tester and on all cylinders. I could not get either compression tester to seal in any of the cylinders.

I then installed one injector at a time, sprayed it down, and spun the engine over; none of these had any blow. I can tell you that there is a lot more compression then 300PSI, the manual is correct at this point. I reassembled everything, bleed the air out of the injector lines, and she started up with ease. No miss fires, no white smoke, not hardly a couple of cranks and she was running smooth.

Thanks for all the replies.

 

[Powered By IH]

Update: After reading though these post as well as sifting through my 4430 manuals I came to the conclusion that maybe in fact that the compression listed in the 4520-tech manual was wrong. At the same time, I check everything again, checked the valve lift which per the manual was within specification and still the 300PSI compression level.

At this point I adjusted the exhaust valve clearance from 0.020” to 0.028” as per the 4430 manuals so see if this would increase compression. When I did this, I left the compression tester installed and when I was turning the engine over by hand I could hear blow by. I sprayed soapy water around the compression tester, and it was not sealing in the head. I sprayed it again and spun it over with the starter and the blow by was incredibly, I still managed to get 300PSI on the tester. In repeated this with a second compression tester and on all cylinders. I could not get either compression tester to seal in any of the cylinders.

I then installed one injector at a time, sprayed it down, and spun the engine over; none of these had any blow. I can tell you that there is a lot more compression then 300PSI, the manual is correct at this point. I reassembled everything, bleed the air out of the injector lines, and she started up with ease. No miss fires, no white smoke, not hardly a couple of cranks and she was running smooth.

Thanks for all the replies.

Ya know, that was a thought that I had earlier. Was going to say something but then forgot about it until now.

Oh well.

 

[used red MN]

Update: After reading though these post as well as sifting through my 4430 manuals I came to the conclusion that maybe in fact that the compression listed in the 4520-tech manual was wrong. At the same time, I check everything again, checked the valve lift which per the manual was within specification and still the 300PSI compression level.

At this point I adjusted the exhaust valve clearance from 0.020” to 0.028” as per the 4430 manuals so see if this would increase compression. When I did this, I left the compression tester installed and when I was turning the engine over by hand I could hear blow by. I sprayed soapy water around the compression tester, and it was not sealing in the head. I sprayed it again and spun it over with the starter and the blow by was incredibly, I still managed to get 300PSI on the tester. In repeated this with a second compression tester and on all cylinders. I could not get either compression tester to seal in any of the cylinders.

I then installed one injector at a time, sprayed it down, and spun the engine over; none of these had any blow. I can tell you that there is a lot more compression then 300PSI, the manual is correct at this point. I reassembled everything, bleed the air out of the injector lines, and she started up with ease. No miss fires, no white smoke, not hardly a couple of cranks and she was running smooth.

Thanks for all the replies.

Looks like brendonh nailed it, try to meet the compression spec was “Ghost hunting” but the who knows if your tester adapter was leaking off compression. The use of two compression testers in my mind and I’m sure others usually would confirm a valid test. I am surprised by this because by looking at the parts diagram it shows pencil injectors for the vertical install pumps like you described is on yours. I don’t think you would have to search a very big circle of tractor mechanics to find one that has an old pencil injector modified for compression testing. Be that as it may.
I hate to doomsday you but there is a possibility you are going to find the pump head is worn out and it is not going to like to start for you when it’s hot. All the best to you, hope it proves to serve you well. Looks like you have it painted up pretty nice anyway.

 

[Fritz Maurer]

What turned out to be the problem after 3 pages of having everyone believe it was low compression?

 

[Powered By IH]

What turned out to be the problem after 3 pages of having everyone believe it was low compression?

OP just said:

At this point I adjusted the exhaust valve clearance from 0.020” to 0.028” as per the 4430 manuals so see if this would increase compression. When I did this, I left the compression tester installed and when I was turning the engine over by hand I could hear blow by. I sprayed soapy water around the compression tester, and it was not sealing in the head. I sprayed it again and spun it over with the starter and the blow by was incredibly, I still managed to get 300PSI on the tester. In repeated this with a second compression tester and on all cylinders. I could not get either compression tester to seal in any of the cylinders.

Compression testers were leaking I guess.

 

[Glen D Anderson]

FWIW

While this is not an exact apples to apples comparison, the Reliance high compression kit we installed in our '72 4020 resulted in 380 - 400 PSI cranking compression tested right after engine assy. Was planning on retesting after break-in but never got around to it.......

Prior to the overhaul, the engine had mostly sub-300 PSI readings as I recall. Due to engine wear of which most was valve leakage.

The head was rebuilt with all new valves & seats with protrusion set right at max. spec.

 

[Glen D Anderson]

At the time I remember not being very impressed with the compression readings wondering what, if any, difference the "High compression" kit actually made over stock pistons.