Different Kohler K181 Camshafts

[MarkPalmer 81]

Unknown to me that Kohler did this, but a nice looking used cam I got for my K181 is a little different from the cam I removed from my engine, (off WH 867) the two obviously being from different spec’ed engines. The cam removed had the common centrifugal compression release that would bump open the exhaust valve at low RPM’s. The replacement cam I have (out of a K181 from a JD 110) has instead a centrifugal spark advance that retards the ignition points timing a bit at low RPM’s to reduce startup loading. Lobe positions, timing mark, fuel pump lobe and all else look to be identical. Wondering if anyone else has tried swapping these two cams on K181's and if there is noticeable difference in starting or running between the two?

-Mark-

[ol550 830]

Have only found the advance type cam in the 701 K161.

[TT-(Moderator) 1,145]

The two-piece spark advance camshafts were used up until the ACR system came out, which - near as I can tell - was somewhere in late 1964.

I have no idea about the comparison of the spark advance vs. ACR camshafts, but I do know that the area between the lobes on a K-181 (and later K-161) camshaft is machined for connecting rod clearance due to the longer stroke.

I honestly doubt you'd notice a difference either way, but I would probably stick with the newer ACR cam when given the choice.

[MarkPalmer 81]

I'm going to give the older spark advance cam a try, only because I have it and there looks to be very little wear on it. I would prefer using the newer ACR cam, but what the hey if it runs good than I'll be happy. If not I take it apart again. I noticed in the Kohler books that the ACR cam was the official replacement cam for all the older K181's with the spark advance cam, so at least I feel some comfort knowing the two cams will interchange, I'm just working a bit backwards in time.

-Mark-

[TT-(Moderator) 1,145]

Almost forgot......

Pre-ACR engines used the same tappet on both the intake and exhaust.

I believe the exhaust tappet on the ACR engines is shorter than the intake tappet, but won't swear to it without making a trip to the shop. :scratchead:

[MarkPalmer 81]

Almost forgot......

Pre-ACR engines used the same tappet on both the intake and exhaust.

I believe the exhaust tappet on the ACR engines is shorter than the intake tappet, but won't swear to it without making a trip to the shop.

Yes, you are correct that the exhaust tappet is shorter on the ACR engine. I do have the tappet set that was used with my non-ACR cam that are both the same length, and will be sure to check the valve stem to tappet clearances during re-assembly. Hopefully it will work with my current set of valves.

-Mark-

[buckrancher 2,694]

pre acr cams also need the point cam as it was not part of the camshaft like the acr cams

[MarkPalmer 81]

I do have the small section of the cam for the points, I had to reference it with my broken ACR cam to make sure it's in the right position in the flyweight fingers so the points timing isn't 180 degrees off. I can see where some fumbling might occur holding the two pieces of the cam together when putting it in the block before the pin can be slid through it.

-Mark-

[buckrancher 2,694]

there should also be alinement dimples on the cam and point cam

Brian

[Erby 15]

A long shot but I am having the same camshaft replacement headache - topic open on forum under engines C-81 Kohler engine keeps cutting out

Did you ever get the spark advance cam to fit into your K181 ACR version?

If so, all tips gratefully received!