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Old 09-05-2010, 11:33 AM
giddyup306 giddyup306 is offline
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Join Date: Sep 2010
Location: Nebraska
Posts: 17
Default K321 +.030" Rebuild Questions (ACR, Turning Torque, Points Gap)

Hello everyone. Let me start by saying that I did some searching, but I couldn't find what I was looking for. I'm sorry if this has been covered a million times before...

Anywho, I'm in the process of rebuilding a K321S for my Dad's '76 1450, and it's been fighting me every inch of the way! I was told by two small engine shops that rebuilding these small engines are more trouble than they are worth. Boy were they right...

For starters (pun) some how the nut on the starter backed off, and was binding. After rebuilding the starter the battery had gone south (froze last winter). The throttle shaft on the carb was wore too bad and even though there is a rebuild kit, I had to get a new one. After all this I had a wierd problem where it would intermittenty not want to crank. It seemed to just do it at random. Sometimes I could crank on it for 30 seconds. Other times it would not crank at all. I was convinced that this was an electrical problem, but I couldn't find anything wrong with the starting circuit. It seemed like when I pulled the spark plug that it would try to crank (but sometimes it wouldn't) when that happened. I then checked the ARC to find out that it was not functioning at all! This is funny because I never touched the cam or the valves. The machine shop did all that when they put in the new valves. This leads to my first question. Is there a better set of instructions on how to set the ACR? I didn't take the spring off, so I'm not 100% on how it goes back on (or if anything is even missing). The pictures in the Kohler manual are a joke (I have the old style ACR). I decided to take the engine out at this point and disassemble and reassemble it double checking everything. When I went to check the rod bolts this is were I found something grossly wrong. When I built the engine, I used the manual that came with the rebuild kit. They told me to tighten the rod bolts 10 ft. lbs. MORE than what the Kohler manual said. It also said nothing about torqueing them 20% over then loosining them and retightening them. I did this and the turning torque was literally cut in half. This leads into my next question. I didn't see anywhere in the manual whre it said anything about turning torque on these engines. Even after retorqueing the rod it still seems to turn too hard. It turns pretty easy with a 1/2" rachet, but I can't turn it over by hand. To me this just seems wayyy too tight. On a lot of modern 4 cylinder engines I can turn the crank over with my bare hand if the spark plugs are out. I do realize that the K321 isn't broken in yet, too. I do have a mic to check the crank, but I don't have a cock-it-lock-it-rock-it gauge to check the big end of the rod, and see if the machine work is right. What is the rod suposed to be at when you measure it with plastigague (once again I didn't see that in the service manual)? This is a .010" undersized rod BTW. Last one... In the rebuild manual it said to double up head gaskets if you have hard starts, or experience spark knock. I don't like this idea, and think it would be better to adjust the plug gap. What should that be set at for the .030" overbore? I read in the Library that it might run anywhere from .015-.020".

Also to add insult to injury I forgot/lost how the throttle and choke cables go on this thing! I know I should have been paying attention, but I started this project 5 years ago. I have too many projects going on at once, and my dad lives about 80 miles away from me, so it's hard to find time to work on this stuff when you work all the time. He wants it to work this winter because it has a snow blower.

Thanks in advance and have a safe and fun Labor Day Weekend!

Mike


PS the link for the K series manuals gives an error in the Technical Library section.
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