Bobcat 6??

[Shaf]

I purchased a Bobcat, I think 610, but not sure how to tell, previous owner wasn't sure either, about 1 1/2 years ago for a specific project. I was building a small pond in the back yard. I paid $3000 for it off of the local Craigslist. I had it no more than a couple weeks and the headgasket blew, also put burn on the head. I bought a new gasket and head off of ebay and it ran for a week or less and blew again. This time it didn't ruin the head, I bought another gasket off of ebay and ran for a little while and blew again. Probably stupid, but I finished the project last summer running on 3 cyl's working in short spurts. Then, last winter I tried clearing the snow from our 250' driveway and something else happened, maybe the other cyl, don't know haven't pulled apart yet. Sorry for the long winded introduction. I have several questions: How do I know which Bobcat, which engine, I have? I had sent pictures to the ebay guy and bought a head for a Wisconsin VH4 or VH4D. One bolt in the head near where it was blowing, had a heli-coil insert. Why would it overheat and blow the head gasket?

 

[OldMachinist]

The D at the end of a Wisconsin model number means it has stellite valves and seats other than that the engines are the same. When you have an engine apart you can tell which one you have because stellite valves are non-magnetic. The main differences between the Bobcat 600 and 610 are they increased the rpms and put a higher capacity pump on the 610 and added some ballast weight. They both used the Wisconsin VF4D engine and the machines are the same physical size. The 600 was rated at 25HP and the 610 at 30HP.
The main reason an air cooled engine overheats is the cooling fins are clogged(dirt, grease, insect and rodent nests). Reasons beyond that are improper valve clearance, carbon build up on the heads and pistons and a exhaust restriction.

 

[OldMachinist]

The D at the end of a Wisconsin model number means it has stellite valves and seats other than that the engines are the same. When you have an engine apart you can tell which one you have because stellite valves are non-magnetic. The main differences between the Bobcat 600 and 610 are they increased the rpms and put a higher capacity pump on the 610 and added some ballast weight. They both used the Wisconsin VF4D engine and the machines are the same physical size. The 600 was rated at 25HP and the 610 at 30HP.
The main reason an air cooled engine overheats is the cooling fins are clogged(dirt, grease, insect and rodent nests). Reasons beyond that are improper valve clearance, carbon build up on the heads and pistons and a exhaust restriction.

 

[Shaf]

The D at the end of a Wisconsin model number means it has stellite valves and seats other than that the engines are the same. When you have an engine apart you can tell which one you have because stellite valves are non-magnetic. The main differences between the Bobcat 600 and 610 are they increased the rpms and put a higher capacity pump on the 610 and added some ballast weight. They both used the Wisconsin VF4D engine and the machines are the same physical size. The 600 was rated at 25HP and the 610 at 30HP.
The main reason an air cooled engine overheats is the cooling fins are clogged(dirt, grease, insect and rodent nests). Reasons beyond that are improper valve clearance, carbon build up on the heads and pistons and a exhaust restriction.

If they both used the VF4D, does that mean I don't have either, or someone changed the engine? Thank you for the spec sheets, I'll look this weekend and see if I can figure out what I have? I pulled the Bobcat into the garage for the winter. I thought I might pull the motor to fix, maybe I don't need to? It also could use good cleaning, looks like everthing in there is caked with old oil, hyd oil or grease. The heads don't appear to have clogged fins, but I'll look a little closer. I have never head the 2nd head off and the tins are still there, but I didn't see any carbon build up on the 1st. I haven't looked at valve clearances or exhaust restrictions, but will look through the winter. I've read in a few places that if all the tin isn't in place around the engine, that would cause it to overheat, guess because it disrupts the airflow. I also read somewhere, maybe here?, that sometimes the distributor mechanics rust and leaves the timing advanced, blowing the head gaskets? When replacing the head gasket, I'm not sure the heli-coil would allow me to tighten, it felt like it was giving. I didn't torque it though, guess I need to buy one if I'm going to go much deeper into the engine? I am not a mechanic by trade and I know I'm a little over my head. I used to work on my motorcyles when I was younger and cars til they started putting space shuttle stuff under the hood and dashboard. But any advice or knowledge you can impart is appreciated.

 

[OldMachinist]

If they both used the VF4D, does that mean I don't have either, or someone changed the engine? Thank you for the spec sheets, I'll look this weekend and see if I can figure out what I have? I pulled the Bobcat into the garage for the winter. I thought I might pull the motor to fix, maybe I don't need to? It also could use good cleaning, looks like everthing in there is caked with old oil, hyd oil or grease. The heads don't appear to have clogged fins, but I'll look a little closer. I have never head the 2nd head off and the tins are still there, but I didn't see any carbon build up on the 1st. I haven't looked at valve clearances or exhaust restrictions, but will look through the winter. I've read in a few places that if all the tin isn't in place around the engine, that would cause it to overheat, guess because it disrupts the airflow. I also read somewhere, maybe here?, that sometimes the distributor mechanics rust and leaves the timing advanced, blowing the head gaskets? When replacing the head gasket, I'm not sure the heli-coil would allow me to tighten, it felt like it was giving. I didn't torque it though, guess I need to buy one if I'm going to go much deeper into the engine? I am not a mechanic by trade and I know I'm a little over my head. I used to work on my motorcyles when I was younger and cars til they started putting space shuttle stuff under the hood and dashboard. But any advice or knowledge you can impart is appreciated.

The head gasket is the same on the TH,TJ,VE,VF,VH,W4 Wisconsin engines so likely you still have the VF4D. Yes, if some of the tin is missing the engine could run hot. If the timing was stuck advanced it would be hard to start. If the Heli-Coil was properly installed it should hold the right torque. I uploaded the section of the service manual for the engine here. http://www.mediafire.com/file/dzmdifmkimm/wisconsin_engine_service.pdf

 

[OldMachinist]

The head gasket is the same on the TH,TJ,VE,VF,VH,W4 Wisconsin engines so likely you still have the VF4D. Yes, if some of the tin is missing the engine could run hot. If the timing was stuck advanced it would be hard to start. If the Heli-Coil was properly installed it should hold the right torque. I uploaded the section of the service manual for the engine here. http://www.mediafire.com/file/dzmdifmkimm/wisconsin_engine_service.pdf

I did a little further digging and found a reference to the 610 having the VH4D engine so the spec sheet ether has a typo or there was a change sometime during the build years. I found the reference to the VH4D in the general service section of the service manual where it shows how to set the timing.
http://www.mediafire.com/file/jnmytjzwgjj/general_service.pdf

 

[OldMachinist]

I did a little further digging and found a reference to the 610 having the VH4D engine so the spec sheet ether has a typo or there was a change sometime during the build years. I found the reference to the VH4D in the general service section of the service manual where it shows how to set the timing.
http://www.mediafire.com/file/jnmytjzwgjj/general_service.pdf

Here's image of the tin that should be there.

 

[jerry]

I had a 610 vh4d and the distributor does have a centrifugal advance in it and it was rusted up tight in mine. Take the point mounting plate out and you can see it down there.

 

[Shaf]

I had a 610 vh4d and the distributor does have a centrifugal advance in it and it was rusted up tight in mine. Take the point mounting plate out and you can see it down there.

Thanks Jerry, I'll check today.

 

[Shaf]

Thanks Jerry, I'll check today.

Thanks OldMachinist, the diagrams are great. The bottom tin was laying in the bottom of the engine compartment unbolted. I've been looking at ebay and other websites for a service manual. I've seen them advertised as 7?, 100, and 304 pages. Can all of these be correct. My first inclination would be to buy the 304 page manual, do you or anyone have advice on what manual(s) I should have in my garage.

 

[OldMachinist]

Thanks OldMachinist, the diagrams are great. The bottom tin was laying in the bottom of the engine compartment unbolted. I've been looking at ebay and other websites for a service manual. I've seen them advertised as 7?, 100, and 304 pages. Can all of these be correct. My first inclination would be to buy the 304 page manual, do you or anyone have advice on what manual(s) I should have in my garage.

No need to buy a manual I've uploaded the rest of the sections this morning.
http://www.mediafire.com/file/zqr4yzbzjjj/610_parts_manual.pdf
http://www.mediafire.com/file/mjikwojizmm/alphabetical_index.pdf
http://www.mediafire.com/file/jzribgw2nqm/deutz_engine_service.pdf
http://www.mediafire.com/file/2zmtvwzjt0y/drive_system.pdf
http://www.mediafire.com/file/znaumzuyoh3/foreword.pdf
http://www.mediafire.com/file/ojzjymmfm44/hydraulic_system.pdf
http://www.mediafire.com/file/vkitjotbmz2/petter_engine_service.pdf
http://www.mediafire.com/file/j0q0ltiii5r/specification.pdf
http://www.mediafire.com/file/znnu01fztyg/troubleshooting.pdf

 

[Shaf]

No need to buy a manual I've uploaded the rest of the sections this morning.
http://www.mediafire.com/file/zqr4yzbzjjj/610_parts_manual.pdf
http://www.mediafire.com/file/mjikwojizmm/alphabetical_index.pdf
http://www.mediafire.com/file/jzribgw2nqm/deutz_engine_service.pdf
http://www.mediafire.com/file/2zmtvwzjt0y/drive_system.pdf
http://www.mediafire.com/file/znaumzuyoh3/foreword.pdf
http://www.mediafire.com/file/ojzjymmfm44/hydraulic_system.pdf
http://www.mediafire.com/file/vkitjotbmz2/petter_engine_service.pdf
http://www.mediafire.com/file/j0q0ltiii5r/specification.pdf
http://www.mediafire.com/file/znnu01fztyg/troubleshooting.pdf

Thanks very much for you help. I pulled the head this morning and took a few pictures, maybe it will tell you something. The only thing it tells me is that I have a problem, I knew that before. I have to run an errand right now, but I'll try to post them in a little while.

 

[Shaf]

No need to buy a manual I've uploaded the rest of the sections this morning.
http://www.mediafire.com/file/zqr4yzbzjjj/610_parts_manual.pdf
http://www.mediafire.com/file/mjikwojizmm/alphabetical_index.pdf
http://www.mediafire.com/file/jzribgw2nqm/deutz_engine_service.pdf
http://www.mediafire.com/file/2zmtvwzjt0y/drive_system.pdf
http://www.mediafire.com/file/znaumzuyoh3/foreword.pdf
http://www.mediafire.com/file/ojzjymmfm44/hydraulic_system.pdf
http://www.mediafire.com/file/vkitjotbmz2/petter_engine_service.pdf
http://www.mediafire.com/file/j0q0ltiii5r/specification.pdf
http://www.mediafire.com/file/znnu01fztyg/troubleshooting.pdf

I am having trouble pasting the pictures here and not sure why. I've changed to HTML, I copied the picture, but when I paste it's all white? Do I still have a setting incorrect?

 

[OldMachinist]

I am having trouble pasting the pictures here and not sure why. I've changed to HTML, I copied the picture, but when I paste it's all white? Do I still have a setting incorrect?

The image has to hosted on the web like on PhotoBucket. If it's just on your computer it won't work.

 

[Tazza]

The image has to hosted on the web like on PhotoBucket. If it's just on your computer it won't work.

If you didn't torque the head down, your gasket can and will leak.
The other thing it could be, is the fuel mixture. If its too lean it burns hotter and can damage head gaskets and valves.
Just a few possibilities.

 

[Shaf]

The image has to hosted on the web like on PhotoBucket. If it's just on your computer it won't work.

You said the heli-coil shouldn't be a problem if it was done right. You can see it upper middle. Looks suspect to me. I know when I tightened the head up last time, it didn't feel good. You can also see the starter below, what cylinder # is this?

These are the two heads, left one I pulled last year. I was surprised to see it didn't burn in the same spot, it's one bolt over? I don't own a torque wrench, but I will soon. I also didn't know the tightening sequence. I wonder if that wasn't part of my problem?

The distributor inside, looks in rough shape. The tab on the bottom wasn't holding screw, it's split if you can see it in the picture.

I took this picture and sent it to the guy when the head blew the first time.
As you can see, I know shortage of gunk either.

 

[Shaf]

I am having trouble pasting the pictures here and not sure why. I've changed to HTML, I copied the picture, but when I paste it's all white? Do I still have a setting incorrect?

No I didn't torque it down, I don't own a torque wrench, but I will before I put it back together. The guy I bought it from said he bought it for one project and that was done and he just wanted to get his money back. He said he didn't have any problems with it, other than replacing the starter? He also put new vinyl over the seat and welded on a roll cage.

 

[OldMachinist]

No I didn't torque it down, I don't own a torque wrench, but I will before I put it back together. The guy I bought it from said he bought it for one project and that was done and he just wanted to get his money back. He said he didn't have any problems with it, other than replacing the starter? He also put new vinyl over the seat and welded on a roll cage.

When viewing the engine from the flywheel end, the number 1 cyl is on the left bank nearest the flywheel and the number 3 cyl is directly behind #1. On the right bank, starting nearest the flywheel are #2 and #4. The head bolt tightening sequence is on page 17 of the engine service manual I uploaded and they should be torqued to 22-24 ft-lbs. If the Heli-coil won't hold then it may have to be fixed with a solid insert if there's room for one.

 

[Shaf]

When viewing the engine from the flywheel end, the number 1 cyl is on the left bank nearest the flywheel and the number 3 cyl is directly behind #1. On the right bank, starting nearest the flywheel are #2 and #4. The head bolt tightening sequence is on page 17 of the engine service manual I uploaded and they should be torqued to 22-24 ft-lbs. If the Heli-coil won't hold then it may have to be fixed with a solid insert if there's room for one.

Can the head bolt be drilled and tapped to a 3/8, or do I need to purchase a new head? A friend of my told me to put in 2 heli-coils one on top of the other, would that work? Thanks again for all your help.