1972 Bobcat M610 problem

[dadsbobcat]

I am a novice mechanic at best, so i'm just looking for some advice on what one may feel the problem may be.. When using my dad's bobcat I was hearing a chirping like sound coming from the clutch area when the engine became under load such as turning or lifting. It did not make the sound when driving or when little power was required. None the less, it was always making the sound every time the engine had to work a bit more. I have greased the fittings but to no avail. This winter the same chirping sound has stopped but has been replaced by a constant hissing sound of air. When it's running I constantly hear this hissing or chugging of air as the engine runs. It gets worse as the engine is under load just like before. I believe its coming from the clutch area but cannot be sure. Do I have a seal out? Any ideas or suggestions would be extremely helpful. Am I doing more damage by continuing to operate the machine?

 

[6brnorma]

You say you are a novice so lets first establish exactly what you are talking about. The 610 does have clutches…….four……two inside each chain case. There are no grease fittings on those clutches as they are oil bath. I have never heard them make the sounds described.
The machine also has a "Variable" speed sheave (on the engine) with a zerk and the "driven" sheave (spring, under the seat) that has a zerk. The belt will make sounds similar to what you have described while riding on those sheaves.

 

[gearbox]

You say you are a novice so lets first establish exactly what you are talking about. The 610 does have clutches…….four……two inside each chain case. There are no grease fittings on those clutches as they are oil bath. I have never heard them make the sounds described.
The machine also has a "Variable" speed sheave (on the engine) with a zerk and the "driven" sheave (spring, under the seat) that has a zerk. The belt will make sounds similar to what you have described while riding on those sheaves.

I am thinking you may have a blown headgasket . Have it checked out right away and you may get by with a new head gasket . leave it go it could cost a head or even a set of jugs .

 

[dadsbobcat]

You say you are a novice so lets first establish exactly what you are talking about. The 610 does have clutches…….four……two inside each chain case. There are no grease fittings on those clutches as they are oil bath. I have never heard them make the sounds described.
The machine also has a "Variable" speed sheave (on the engine) with a zerk and the "driven" sheave (spring, under the seat) that has a zerk. The belt will make sounds similar to what you have described while riding on those sheaves.

It is indeed the variable drive sheave I was referring to. I just can't isolate exactly where the sound is coming from. It is a hissing sound similar to the sound an old john deere 2 cylinder might make when the petcocks are open.

 

[6brnorma]

It is indeed the variable drive sheave I was referring to. I just can't isolate exactly where the sound is coming from. It is a hissing sound similar to the sound an old john deere 2 cylinder might make when the petcocks are open.

Follow through on 'gearbox's' suggestion and eliminate the head gasket possibility. I normally do a compression check…….cheap and easy.

 

[dadsbobcat]

Follow through on 'gearbox's' suggestion and eliminate the head gasket possibility. I normally do a compression check…….cheap and easy.

I did a compression check.. The outside 2 cylinders had a full 120 lbs of compression. The inside cylinders were both only producing around 70 lbs of compression. Being a novice mechanic I am determined to change this myself. Can you give me any details that would be helpful such as sequence to tighten head bolts and torque on the bolts? Any diagrams that may be helpful.. I would greatly appreciate any helpful tips that would make this a successful project for me.. Thank you

 

[6brnorma]

I did a compression check.. The outside 2 cylinders had a full 120 lbs of compression. The inside cylinders were both only producing around 70 lbs of compression. Being a novice mechanic I am determined to change this myself. Can you give me any details that would be helpful such as sequence to tighten head bolts and torque on the bolts? Any diagrams that may be helpful.. I would greatly appreciate any helpful tips that would make this a successful project for me.. Thank you

It's not complicated. Clean both surfaces…….make sure there is no debris in the cylinders or on the two surfaces. Snug all bolts up then set your torque wrench to 22-24 lbs…….start with the center most bolt and work your way out doing opposite bolts each time until you have done each of them. Once you have done all the bolts ….. go back and do them all again just to make sure the torque is accurate on all of them.

 

[alchemysa]

It's not complicated. Clean both surfaces…….make sure there is no debris in the cylinders or on the two surfaces. Snug all bolts up then set your torque wrench to 22-24 lbs…….start with the center most bolt and work your way out doing opposite bolts each time until you have done each of them. Once you have done all the bolts ….. go back and do them all again just to make sure the torque is accurate on all of them.

FOR 610 parts diagrams and repair manuals (Free) Copy and paste this into your browser. The two top folders have just about everything you need including parts diagrams... http://ardiehl.de/Bobcat/ FOR VH4D Wisconsin engine repair manual and parts diagrams (free)... https://www.m-and-d.com/pdfs/Wisconsin/vh4d.pdf http://www.wincogen.com/files/downloads/winco_engine_maintenance/wisc_vh4d_repair_manual.pdf

 

[alchemysa]

FOR 610 parts diagrams and repair manuals (Free) Copy and paste this into your browser. The two top folders have just about everything you need including parts diagrams... http://ardiehl.de/Bobcat/ FOR VH4D Wisconsin engine repair manual and parts diagrams (free)... https://www.m-and-d.com/pdfs/Wisconsin/vh4d.pdf http://www.wincogen.com/files/downloads/winco_engine_maintenance/wisc_vh4d_repair_manual.pdf

(Ignore my previous post. He's the same thing with some spacing)
FOR 610 parts diagrams and repair manuals (Free)
Copy and paste this into your browser. The two top folders have just about everything you need including parts diagrams...
http://ardiehl.de/Bobcat/
FOR VH4D Wisconsin engine repair manual and parts diagrams (free)...
https://www.m-and-d.com/pdfs/Wisconsin/vh4d.pdf
http://www.wincogen.com/files/downloads/winco_engine_maintenance/wisc_vh4d_repair_manual.pdf

 

[dadsbobcat]

(Ignore my previous post. He's the same thing with some spacing)
FOR 610 parts diagrams and repair manuals (Free)
Copy and paste this into your browser. The two top folders have just about everything you need including parts diagrams...
http://ardiehl.de/Bobcat/
FOR VH4D Wisconsin engine repair manual and parts diagrams (free)...
https://www.m-and-d.com/pdfs/Wisconsin/vh4d.pdf
http://www.wincogen.com/files/downloads/winco_engine_maintenance/wisc_vh4d_repair_manual.pdf

Thanks for all the great links to manuals and diagrams. It was really helpful. My head gasket project turned out very successful.. Thanks again

 

[dadsbobcat]

It's not complicated. Clean both surfaces…….make sure there is no debris in the cylinders or on the two surfaces. Snug all bolts up then set your torque wrench to 22-24 lbs…….start with the center most bolt and work your way out doing opposite bolts each time until you have done each of them. Once you have done all the bolts ….. go back and do them all again just to make sure the torque is accurate on all of them.

Thanks for the advice. Everything is very helpful. I have a few more projects to deal with on the bobcat and hope you can give some advice in the future.

 

[6brnorma]

Thanks for the advice. Everything is very helpful. I have a few more projects to deal with on the bobcat and hope you can give some advice in the future.

Just a side note for anyone that may read this thread in the future. Alchemysa was kind enough to post a link to the VH4D engine on the Wisconsin site…..be aware that this is the standard VH4D and NOT the engine spec'ed out for the Bobcat. The Bobcat Wisconsin VH4D will have a different crank, crank gear, idler gear/bearings, distributor gear and distributor housing with output shaft. IIRC everything else is the same.