My Tractor Forum banner

21 - 40 of 114 Posts

·
Registered
Joined
·
155 Posts
Discussion Starter #21 (Edited)
well, that explains why she smoked like a choo-choo train I guess... least I'm starting from STD and should have lots of material to expend. from my measurements above with everything being 3.25" or higher, I should be able to do just .010" over bringing it to 3.26" top to bottom in both X/Y. is that correct? I'm guessing let the machinist do his measurement and determine what the bore needs to be cut to and then after that is done have him provide me the new spec for the replacement piston?
 

·
Registered
Joined
·
908 Posts
Looking at your measurements, I'd say you're safe getting .010" over pistons and letting the machine shop bore to the piston sizes. You may (??) have some areas that don't clean up 100%, but it mostly depends on your "feel" as to what the actual measurement is. A tight "feel" can easily result in readings being large .001" - .003" and a loose fell .001" - .003" small! I like the second part of your statement...up to a point! Bring block to machinist, let him measure, and then STOP. Get pistons, give to machinist, and THEN let him bore!

As far as pits/small holes in top of block, don't worry about them. Even if they're right under the gasket, the gasket will seal. DO CHECK the top of the block AND the bottom of the head for flatness. I'm thing block will be OK and spec on head is around .003" -.005" flat. This is critical if you expect head gasket to seal!

You're doing fine, keep going! Bob
 

·
Registered
Joined
·
155 Posts
Discussion Starter #23
progress...got those stuck 4 phillips head screws holding the grass screen off. PB blaster, wait for 2 hours, tap with hammer...impact wrench....only wrecked one. :) flywheel came off no problemo.
 

·
Registered
Joined
·
155 Posts
Discussion Starter #24
got a quote from a local machinist to cut the bore - $100.00. I'll be delivering it fully disassembled. I'll get him to do measurements first as you suggested Bob. then I'll order the piston/crank/rings. what's the method of determining the usableness of the bearings or is it suggested to replace them at this time anyway? will post pics of the block shortly.
 

·
Registered
Joined
·
908 Posts
"then I'll order the piston/crank/rings." Inspect before ordering crank...that may be a little pricey! Check journals where main bearings mount. If no signs of bearings spinning (scoring on shaft), it'll be OK. Visually inspect rods and crank rod journal for scoring. If no deep scoring on rod journals or rod, get "Plastigage" from auto parts store. Follow directions on package and check clearance. If no scoring and clearance within spec, your good to go!

Plastigage: I haven't used that stuff in 45+ years and was very surprised to see it still available! Plastigage is a precision diameter length of soft plastic. Cut into a strip long enough to cover the width of the rod journal/the width of the rod. Clean crank & rod journal and lay plastigage on crank journal. Install rod and tighten rod bolts. I used to torque to about 50% and try not to rotate rod. Remove rod end cap and compare width of "crushed" Plastigage to chart on package. There's your rod bearing clearance! If my 71 year memory serves me correctly, Plastigage comes in different thicknesses for different bearing clearances. Get clearance spec and then appropriate Plastigage.

This is also a good check for your "feel" with measuring tools. Measure crank rod journal, measure rod bore...rod cap bolted with bolts snug... Calculate difference/clearance and check with Plastigage. I'd use Plastigage for determining usability!

Main bearings: Kohler manual says if they're not scored, rotate smoothly & quietly, reuse them. I'd replace them anyhow! Check jdparts for part numbers and them price out. If your budget can afford it, get'em! By your previous pics, your block looks REALLY GOOD inside, but I'd replace bearings anyhow. Your $$, your final choice. Bob
 

·
Registered
Joined
·
155 Posts
Discussion Starter #26 (Edited)
thx for your helpful info Bob. :) will pick me up some of that plastigage stuff. I watched Taryl use it. He's great for showing us DIYers how to gitter done. I have the block fully disassembled, cleaned thoroughly inside and out and painted on the exterior. head to the machinist hopefully tomorrow.
 

Attachments

·
Premium Member
Joined
·
269 Posts
painted on the exterior
All the machinist I know will hot tank everything before they do any work. I hope your time and paint wasn't wasted.
My guy bores the blocks before I order the pistons. .010 might look like it'll clean up by the measurements, but there is a good chance that once it's bored, it might have to go to .020 to get a good clean bore. . Out of the last 4 blocks I've had done, 2 had to go .020.

Once it's bored, I get the pistons and then he hones the cylinder to size.

BTW, I get all my internal parts from Norm at "I Save Tractors" (.com) Very good parts. I've haven't had any problems with them at all.
 

·
Registered
Joined
·
155 Posts
Discussion Starter #28
thx for the info. I've ordered stuff from Norman in the past. the block internal area is a medium gray color. it's in very good condition. the bore has no visible grooves, marks on it except at the very top near the head - from carbon I presume. The hot dip you mention is a chemical solution that does what exactly? the boring is just for the sleeve where the piston rides. Sounds like an unnecessary step in my case. I'll check with the machinist to see if this is required.
 

·
Premium Member
Joined
·
3,460 Posts
The hot dip is just cleaning the block. It fully immerses the whole block, and gets all the oil/sludge/dirt out of all the passages in the engine.
 

·
Registered
Joined
·
155 Posts
Discussion Starter #30
block is @ the machinist. checked out his boring/honing rig. like a big drill press with a large 3 blade stone hone on the end with varying set of stones for cutting.
 

·
Registered
Joined
·
908 Posts
Hopefully, he'll bore the block first. Honing will take the taper out, but not any out of round condition. And I KNOW I'll get a debate of whether or not honing will make a bore round if it's not round to start with! Bob
 

·
Registered
Joined
·
155 Posts
Discussion Starter #32
Hopefully, he'll bore the block first. Honing will take the taper out, but not any out of round condition. And I KNOW I'll get a debate of whether or not honing will make a bore round if it's not round to start with! Bob
he seemed to think from visual inspection and my measurements that the honing would true it up. is shooting for .010" over.
 

·
Registered
Joined
·
155 Posts
Discussion Starter #34
I just finished sanding down the head 180 grit, followed by 220 grit (wet). Used .003 feeler guage after to determine if it is flat. Looks good. Is there any good product to apply to the fins to clean the aluminum up? It is pitted..looks crappy.
 

·
Registered
Joined
·
155 Posts
Discussion Starter #36
just heard from machinist. block is good to go @ .010" over. and as was stated earlier they will dip it in the tank to clean out any material likely pooching my paint job :oops:
 

·
Registered
Joined
·
155 Posts
Discussion Starter #37
block back. paint survived well...:) the machinist took out the stud on the top of the block and the oil dipstick tube. Should that tube be sealed when I put it back into the block with any type of sealant? I have some black permatex RTV silicone stuff...would that be advised?
 

·
Registered
Joined
·
908 Posts
I don't have any hands-on experience with a K241, but I can't see where a little sealant on the oil tube would hurt anything. Put a small amount of RTV on tube and install. Any excess will be pushed up and make a nice seal at the top where the tube meats the block. Don't put any into the hole in the block as that may be pushed down into the block...probably wouldn't hurt, but definitely won't help!

Do you have any type of assembly lube? Auto parts carry many varieties/names and most are pretty good. I used to use STP and never had problems, but you can get a dedicated pre-lube. Coat rods & rod journals, cam shaft journals & cams, and tappets & tappet bores. Coat EVERYTHING that is metal to metal! I even put it into piston ring grooves...smokes a little on start-up! Bob
 

·
Registered
Joined
·
155 Posts
Discussion Starter #39
I don't have any hands-on experience with a K241, but I can't see where a little sealant on the oil tube would hurt anything. Put a small amount of RTV on tube and install. Any excess will be pushed up and make a nice seal at the top where the tube meats the block. Don't put any into the hole in the block as that may be pushed down into the block...probably wouldn't hurt, but definitely won't help!

Do you have any type of assembly lube? Auto parts carry many varieties/names and most are pretty good. I used to use STP and never had problems, but you can get a dedicated pre-lube. Coat rods & rod journals, cam shaft journals & cams, and tappets & tappet bores. Coat EVERYTHING that is metal to metal! I even put it into piston ring grooves...smokes a little on start-up! Bob
I have lots of oil and grease. I have fogging oil that I use to coat the cylinder and piston and carb when I put things away for the winter. question on the bearings. I coated them lightly with engine oil and put them in plastic baggies until I put them back in the block and bearing plate. should they be greased or just use plain engine oil on them?
 

·
Red Plaid is Timeless
Joined
·
949 Posts
A long time ago building race engines, we used a 50/50 mix of STP and white lithium grease for assembly lube.
 
21 - 40 of 114 Posts
Top