K321 +.030" Rebuild Questions (ACR, Turning Torque, Points Gap)

[giddyup306]

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.

[R Bedell]

The link to the K Series Service Manual in the Technical Library Section works for me.

However, Kohler material is best suited if you use Microsoft's Internet Explorer Browser.

[giddyup306]

Originally Posted by R Bedell

However, Kohler material is best suited if you use Microsoft's Internet Explorer Browser.

There's no IE available for Linux.

[R Bedell]

We have no control over what Kohler's site requirements are.

I personally use FireFox and I notice I have problems viewing their site.

If your E-Mail can accept a 15 Meg File, I can send it to you.

[Matt G.]

Here's a direct link to the PDF service manual from Kohler's website.

How far apart was the engine, and were Kohler or aftermarket parts used? You say you have an undersized rod...was the crank turned to the 0.010" under standard undersize? If not...there's your problem. Other things I have seen cause this are too little crank endplay or an improperly assembled electric PTO clutch. Even a rebuilt engine is not that tight, and you should be able to turn it by hand. The ACR is unlikely to be causing the problem, as the starter should be able to spin it over with no problem, even if the ACR isn't functioning. If it turns hard, that has nothing to do with the ACR.

You don't need to double up head gaskets...the compression ratio is very low on these to begin with. The plug gap is independent of engine bore size. I can't remember the plug gap off the top of my head; I know for the twin cylinder Kohlers, it's like 35 thou or something. 10-20 is way too small. 30 thou would probably work. The service manual I linked to will have it.

Oh, and if your small-engine shop says these aren't worth rebuilding...find a new shop. That's pretty poor advice on their part.

Here's a picture of the throttle/choke linkage.

[Hubman]

Originally Posted by R Bedell

We have no control over what Kohler's site requirements are.

I personally use FireFox and I notice I have problems viewing their site.

If your E-Mail can accept a 15 Meg File, I can send it to you.

You can use Skype as a way to send large files . I believe it allows any size file to be sent . Both party's would need to download and install the free skype program .

[giddyup306]

Just thought I'd update...

Before I made my original post, I had the engine on the bench with the electric clutch and the head off. It still seemed to turn hard. I ended up taking it apart where the rod and the crank were the only things that were together. It was way too tight! The crank should have been turned .010", but I don't know if he did it right (he might have just polished it or something). No, I am not using Kohler parts. I know that OE parts > aftermarket parts, but it was either use the cheap stuff that my dad wanted to buy, or see this tractor go to the junk yard...

I can't remember what the brand of the rebuild kit is, but when I ordered it I ordered it .010" on the crank, and .030" on the piston. The rod has a hole drilled in it, so it should be .010". So either the machine work wasn't done right, or the rod was mismarked.

Want to know what really makes me angry? I asked the guy how tight the rod should be when measuring it with plastigague and his exact words were "put it together and don't worry about it". He usually does good work, but if I took it back it would A) take forever to get back, B) he'd probably tell me to eff off. That's what happens when you have no competition.

Speaking of crappy machinists, the guy that did the heads for my Town Car (different machine shop) effed them up royally. Before I even took it out of the machine shop I noticed that one of the heads had a huge gouge in the middle of it. I made him rework both of them before I left. I got the heads back on the engine turning it by hand, and one of the valves was sticking bad. When I took the valve out I noticed that he had only lapped them, and didn't do the three angle that he charged me for. That turned a 12 hour job into a 20 hour job. He wouldn't rework the head claiming that I must have overheated the engine (the engine never ran, nor did I crank it over with the starter). He also wouldn't reimburse me for the head gasket or TTY head bolts. By the time it was all said and done it cost be about + $200. I found out after the fact that the dealership I worked for had to take back the last 5 things including my heads to have reworked.

Long story short I took it to a guy that I knew would get it done right, and I'm having him double check everything. Even if the ACR wasn't working when he got it, he should have told me that it wasn't.

I guess I'm in the wrong field. I'd love to do crappy work, charge people an arm and a leg for labor, and then tell them tough crap when I don't do something right.

The guy I took it to won't be able to get at it 'till the end of next week tho.

[Merk]

Here is a good example of what happens when you buy a cheap rebuild kit and not having the correct gages to check part(s) out after machine work was done. I wouldn't use a kit that has different torque settings that a Kohler manual has.

Standard pratice for me is to check ALL machine surfaces before and after machine shop does their thing. The machine shop will give me a written copy of the measurements if I request them. It will cost a few extra $$$.

Plastigague is a poor substitute to check the diameter of the rod journasl. Plastigague is a poor substitude to check anything in my book.
Any crank that has the crank journal undersize .010 should be mark/stamped .010 on the crank. That is standard policy in my area. That should an industry standard.

by giddyup306
In the rebuild manual it said to double up head gaskets if you have hard starts, or experience spark knock.

Is the rebuild manual the Kohler one or the one that came with the kit? What page is that infomation about installing 2 head gaskets if the info came from a Kohler manual?

How did you determind that the motor needed a .030 piston?