Author Topic: Jkson 6/1 rebuild  (Read 111007 times)

38ac

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Re: Jkson 6/1 rebuild
« Reply #30 on: January 23, 2015, 12:08:27 PM »
Because it was torqued down over that much protrusion I can tell you without looking at it that your head is not flat. At the risk of sounding like a smart arsed know it all this is one of those deals where if your only going to go halfway as in not correcting the protrusion than just leave the head  alone as your just wasting time and money if you mill it flat. Excessive liner protrusion (to an extent)  very much helps to seal the highest pressured joint in the gasket, the top of the liner. Problems is its harder to seal the water jacket. The head bends down around the sleeve when you torque it down and with a little goop around the water passages you wont leak any water.  This works OK until you take it down for decoking, then  you need to have a head gasket on hand because the gasket is ruined during disassembly.  If your going to put some hours on it and thus disassembling for decoking   you would be ahead to get that protrusion down to .001-.003 if your using Indian sandwich gaskets or .000-.001 if your using the Gaskets to Go modern type with fire ring. Then you will need no goop and it will come apart without ruining the gasket. The difference in  spec here being you need some squish to hold the liner down tight with the Indian gasket, it is built into John's gaskets via the fire rings. Also if your going to pay someone to correct the protrusion my suggestion is to have a machinist make the correction in the counterbores in the block instead of sleeve. This is because the Indian sleeves are real consistent in my experience and come overhaul time you can drop one in and it will very likely be OK. If you correct the sleeve plan on having to do same to your replacement sleeves come overhaul time. 

Just some things to think about
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Gippslander

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Re: Jkson 6/1 rebuild
« Reply #31 on: January 23, 2015, 02:01:01 PM »
Because it was torqued down over that much protrusion I can tell you without looking at it that your head is not flat. At the risk of sounding like a smart arsed know it all this is one of those deals where if your only going to go halfway as in not correcting the protrusion than just leave the head  alone as your just wasting time and money if you mill it flat. Excessive liner protrusion (to an extent)  very much helps to seal the highest pressured joint in the gasket, the top of the liner. Problems is its harder to seal the water jacket. The head bends down around the sleeve when you torque it down and with a little goop around the water passages you wont leak any water.  This works OK until you take it down for decoking, then  you need to have a head gasket on hand because the gasket is ruined during disassembly.  If your going to put some hours on it and thus disassembling for decoking   you would be ahead to get that protrusion down to .001-.003 if your using Indian sandwich gaskets or .000-.001 if your using the Gaskets to Go modern type with fire ring. Then you will need no goop and it will come apart without ruining the gasket. The difference in  spec here being you need some squish to hold the liner down tight with the Indian gasket, it is built into John's gaskets via the fire rings. Also if your going to pay someone to correct the protrusion my suggestion is to have a machinist make the correction in the counterbores in the block instead of sleeve. This is because the Indian sleeves are real consistent in my experience and come overhaul time you can drop one in and it will very likely be OK. If you correct the sleeve plan on having to do same to your replacement sleeves come overhaul time.
Just some things to think about

Yes I understand your advice. BTW the guy I bought the roid from here , has had some replacement head gaskets made here in Australia , he very kindly gave me one I will take a pic of it tomorrow
« Last Edit: January 23, 2015, 02:04:33 PM by Gippslander »
Gippsland is in the S.E. corner of mainland Australia

BruceM

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Re: Jkson 6/1 rebuild
« Reply #32 on: January 23, 2015, 04:07:06 PM »
+1 My early experience exactly matches 38ac's scenario for what happens with excessive liner protrusion.  My head became concave from the liner force, and coolant leaks were a never ending problem.  Fix it now, you'll save yourself a lot of time, $, and headaches. 



Gippslander

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Re: Jkson 6/1 rebuild
« Reply #33 on: January 24, 2015, 08:08:05 AM »
Pics of the head gaskets . The original Jkson I pulled out and the Australian made which looks a bit thin and fragile to me .



« Last Edit: January 24, 2015, 09:04:42 AM by Gippslander »
Gippsland is in the S.E. corner of mainland Australia

Gippslander

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Re: Jkson 6/1 rebuild
« Reply #34 on: January 29, 2015, 07:49:46 AM »
I have found a problem. I suspected that my wrist pin is loose in the bush ,  I did some measuring

The wrist pin is 1.2495"   The bore of the bush is 1.2545"

The wrist pin is loose in the bush , it falls right through the bush . I think I will have to fit a new bush ?

Maybe heat up the rod and press out the bush ?

« Last Edit: January 29, 2015, 07:51:58 AM by Gippslander »
Gippsland is in the S.E. corner of mainland Australia

38ac

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Re: Jkson 6/1 rebuild
« Reply #35 on: January 29, 2015, 01:39:50 PM »
Lister technical data shows .0045 as the maximum allowable clearance for the wrsit pin. I never could find a new fit spec so I hone the bushing until the pin is a slip fit. You dont have to heat the small end to remove the bushing or install it but you do need an appropriate driver.
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dieselgman

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Re: Jkson 6/1 rebuild
« Reply #36 on: January 29, 2015, 03:44:45 PM »
A quick seat-of-the-pants method is with the use of your hands and eyes... any perceptible rock in that pin generally indicates excess wear (or slop) in the bushing.
A slip fit means the pin easily slides back and forth without perceptible drag when fitted dry.

dieselgman
« Last Edit: January 30, 2015, 11:23:52 AM by dieselgman »
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Gippslander

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Re: Jkson 6/1 rebuild
« Reply #37 on: January 30, 2015, 07:47:01 AM »
This is a new unused engine I have and the wrist pin should not have that much of a gap in the bush . Just goes to show how the Indian tolerances are less than we should expect them to be .
Gippsland is in the S.E. corner of mainland Australia

Hugh Conway

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Re: Jkson 6/1 rebuild
« Reply #38 on: January 30, 2015, 05:49:25 PM »
This is a new unused engine I have and the wrist pin should not have that much of a gap in the bush . Just goes to show how the Indian tolerances are less than we should expect them to be .
I recently bought a new (Indian) wrist pin for my 6/1. same problem. Bush measures well within tolerance, wrist pin is undersized.
Cheers,
Hugh
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dieselgman

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Re: Jkson 6/1 rebuild
« Reply #39 on: January 30, 2015, 05:59:30 PM »
Our experience with them is that the bushings must be re-sized to properly fit with the pins. Use of a hand-powered precision reamer is adequate in most cases. If done in a machine shop, then an alignment jig may be employed to guarantee a straight and true bore. It would appear that many of the Indian parts are considerably less precise than one would hope for and expect.

dieselgman
« Last Edit: January 30, 2015, 09:11:55 PM by dieselgman »
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carlb23

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Re: Jkson 6/1 rebuild
« Reply #40 on: January 30, 2015, 09:07:32 PM »
After reading this regarding the wrist pin play on your engine I checked mine since i have my engine apart.  My was at .003 clearance. I don't expect to be re-assembling my engine for a few more months when the weather in Southern New Jersey is a little warmer. 

Carl.

Gippslander

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Re: Jkson 6/1 rebuild
« Reply #41 on: January 31, 2015, 09:24:24 AM »
George utterpower's CD , he recommends that the crankshaft  journal should be polished . 

I had a look at my crank journal with a X 60 loupe and it does need a polish . Emery cloth is what most people use ?
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dieselgman

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Re: Jkson 6/1 rebuild
« Reply #42 on: January 31, 2015, 12:38:21 PM »
I have seen some of the shafts that were left pretty rough and needed a 400 grit polishing. Most would do well with 600 grit. We spin ours in a lathe and use 1 1/2" wide cloth rolls to effect the polishing. They can be buffed up to a mirror finish without too much time and effort. A machine shop setup uses the lathe plus a holder that spins the cloth roll along with the crank for final polishing.

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Gippslander

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Re: Jkson 6/1 rebuild
« Reply #43 on: February 03, 2015, 07:39:22 AM »
Been doing some filing  ;)

I have to remove the four large studs from the case . What is the best method of doing this ? I have a stihlson wrench but it might damage the studs .


« Last Edit: February 03, 2015, 08:04:55 AM by Gippslander »
Gippsland is in the S.E. corner of mainland Australia

dieselgman

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Re: Jkson 6/1 rebuild
« Reply #44 on: February 03, 2015, 08:46:47 AM »
Best way is with a stud puller attachment to your socket wrench, you can also "double nut" each stud and simply pull with a socket.

dieselgman
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