Mike C160 251 #1 Posted May 25, 2022 (edited) Greetings Ok, just got done with my cranking issue, now on to some possible service. I have to replace the exhaust nipple as previously stated, But while i have the exhaust off it almost makes sense to look at and check out some other things. 1) valve clearance - I have no idea when it was last done. 2) There is a procedure for adjusting the automatic compression release lift. Is it worth checking these two things out? I am pulling the head to replace the head gasket as I can see its starting to weep. In for a dime in for a dollar? Your thoughts on this would be great. Cheers and Thanks. On valve adjustment, The manual doesnt speak about the compression release. One would think stationary at TDC it would be activated causing a 030 exhaust valve lift. So how does one check the exhaust clearance? Do you have to remove the cam cover and deactivate the compression release? The manual doesnt suggest this, but my moldy old brain does. Edited May 26, 2022 by Mike C160 Share this post Link to post Share on other sites
Snoopy11 5,714 #2 Posted May 25, 2022 (edited) 3 minutes ago, Mike C160 said: Do you have to remove the cam cover and deactivate the compression release? I could be wrong... the boys here will surely correct me if so... but I believe that if you find TDC, then rock the engine back a few degrees... then go back to TDC... it will alleviate the compression release mechanism... Don Edited May 25, 2022 by Snoopy11 1 Share this post Link to post Share on other sites
953 nut 55,224 #3 Posted May 25, 2022 Valve lash is set with the cam lobe away from the lifter. Section 9 of the Kohler Manual found on this site has some good information on ACR. 2 Share this post Link to post Share on other sites
Mike C160 251 #4 Posted May 25, 2022 (edited) 6 hours ago, 953 nut said: Valve lash is set with the cam lobe away from the lifter. Section 9 of the Kohler Manual found on this site has some good information on ACR. So doing some observation and reading, it would appear that the ACR is not in play at TDC. It would appear the ACS "releases the first 2/3rds of the compression stroke. And this reduces the required cranking force placed on the starter. Correct? Cheers Edited May 26, 2022 by Mike C160 I never said I could spell Share this post Link to post Share on other sites
Mike C160 251 #5 Posted May 25, 2022 (edited) Well, I decided that it was best to go ahead and check the operation of the ACR, adjust the valves and replace the head gasket. I had noted earlier it was starting to weep. So nothing surprising went i removed the head. I found the gasket was failing and the torque on the bolts had backed off. The head checked out ok, I am detecting less than .002 warp distortion. So I think its just a case of big thumper motor and a 45 year old head gasket gave us the goat. While the head was off, I did observe the operation of the ACR. I havent measured the ACR lift yet, but I will tomorrow. Ive quit for the day at this point. My observation suggest its most likely going to be within tolerance. But I did take the time to begin proper preparation to installing a new head gasket. Chasing the cylinder head bolt holes with a tap. Clean em' up and clean all the crud out of them. If you dont do this along with cleaning the bolts and washers as well, you wont get a proper torque reading. the resistance the bolt has going into the hole or grubby washers will rob part of the torque value and your head will not be torqued down evenly. Once this is done you can use compressed air to clean the dust out of the holes. Some guy dont do this and the head doesnt go down even. Then they wonder why the head cracked or it blew another gasket. The bore and valve seats look great tho! Better than i expected. That was a nice surprise. I have an old 8 speed I know needs to TLC. Burns a little oil. But not this one. It looks good to go. Cheers for now. Edited May 26, 2022 by Mike C160 1 2 Share this post Link to post Share on other sites
Handy Don 12,217 #6 Posted May 26, 2022 43 minutes ago, Mike C160 said: Correct? Exactly. 2 Share this post Link to post Share on other sites
953 nut 55,224 #7 Posted May 26, 2022 12 hours ago, Mike C160 said: I found the gasket was failing and the torque on the bolts had backed off. Once you fire up the engine and run it up to normal operating temperature for a while you will want to shut it down, cool it off and retorque the head bolts using the same sequence as before. 2 Share this post Link to post Share on other sites
Mike C160 251 #8 Posted May 26, 2022 Well, It wasnt an emergency but they did need adjusting. Intake was 016 and exhaust was 012. At least its done and i can sleep at night now An easy job but not too easy to get to. 3 Share this post Link to post Share on other sites
Handy Don 12,217 #9 Posted May 27, 2022 5 hours ago, Mike C160 said: An easy job but not too easy to get to. Hey you have adjustable valves. If you have to grind the stems to adjust it's even less easy! Share this post Link to post Share on other sites
Mike C160 251 #10 Posted May 27, 2022 13 hours ago, Handy Don said: Hey you have adjustable valves. If you have to grind the stems to adjust it's even less easy! Yeah I spose And you need some real good equipment to grind the end of that valve square and smooth too. However I still feel I paid the admission. Hood off, Exhaust off, Carb of, Fuel lines off, Cables off just to get close to the party. Share this post Link to post Share on other sites
