149 engine teardown for cam replacement - Page 8

Mr Bob · #71 02-26-2018, 09:26 AM

Just another Senior moment J-Mech. I torqued it to 35 Foot Pounds. Don't know why I put 135. Even proof read it twice and still missed it. Thanks for keeping me straight. Did align the timing mark on the crank shaft with the timing mark on the cam gear. Checked it two or three times to be sure it was correct, but that does not mean it is. Turned the crank a couple times and it looked like the timing marks came together correctly. Thanks for every one's help and have a great day.
Bob

DieselDoctor · #72 02-26-2018, 12:59 PM

Keep up the good work Bob. You'll enjoy this tractor more than the others because you are doing the work and learning as you go. There is nothing better than hearing one run when you first fire it up after major repairs.

Mr Bob · #73 02-26-2018, 04:38 PM

I have been working on this tractor for 4 years off and on. Most all the metal parts were painted and ready for reassembly, but tab on camshaft broke and put reassembly on hold. Really hope to get it finished this summer. Most of all, I hope the engine fires up when I get it back together. Have a great day.
Bob

jbrewer · #74 02-26-2018, 06:42 PM

Quote:

Originally Posted by Mr Bob

I have been working on this tractor for 4 years off and on. Most all the metal parts were painted and ready for reassembly, but tab on camshaft broke and put reassembly on hold. Really hope to get it finished this summer. Most of all, I hope the engine fires up when I get it back together. Have a great day.
Bob

We hope so too Bob. If not, well...the crew is here....

Mr Bob · #75 03-01-2018, 09:31 AM

Yesterday the 12" ribbon gauge arrived that I had ordered. Going to check the piston to cyl. clearance today. Have a couple questions that are more than likely stupid to most. Hope some one with more knowledge than me will answer. I have 2 pistons. One that came out of engine at tear down, and a new one that I bought. Both are .010 over pistons. The old one went to the machine shop with engine block.
1. Do you oil the cyl. before sliding in piston and do you install rings to piston before sliding in piston? Reason I am asking about installing rings is because the page on the specs. says "Max ring side clearance", and not piston side clearance.
2. The cyl. was honed at the machine shop. Specs for ring end gap are different for a new bore and a used bore. Would I use the used bore figures or the new bore figures. I am really trying to get this right so please try to understand my confusion. Thanks to all that have helped and have a great day.
Bob

finsruskw · #76 03-01-2018, 09:59 AM

You do have a ring compressor I hope??

J-Mech · #77 03-01-2018, 10:11 AM

First of all, I hope you ordered more than one ribbon gauge. You need several sizes to see what the fit is. It isn't a "one size" deal. You need gauges from about .003" to .008" at least. I have them from like .0015" to .010". What size did you get?

Second, you check skirt clearance at right angles to the piston pin. So, the gauge will be placed on the skirt. See pic below:

piston.jpg

When checking the skirt clearance, I slide the wrist pin into the piston (DO NOT put the circle clips in, OR the rings on the piston), hold the piston upside down at the top of the bore, then hold the ribbon gauge to the piston, then slide it down. You need to do this in at least 4 places. So, like, 12 o'clock, 3 o'clock, 6, and 9. Make sense? You need to find the gauge that lets the piston slide in with some resistance, but not excessive force. How do you know what is excessive? With no experience, you don't. This is why I don't like people overhauling engines that have NO experience doing so.

For the measurement, you use the info in the book on the chart at "piston". I still don't understand why the book gives two different points of measurement on the piston.... it's the only book I've ever seen that on. Instead of trying to figure it out, I'll just tell you, the skirt clearance should be about .004" to .007" For the record, you have a new bore, not a used bore, so you will use the specs accordingly. You also have a new piston. Throw the old one in the junk pile. You are done with it now. It should never have went to the machine shop. Hope they didn't use it to fit to the bore.

On the rings. You have to check ring end gap. The book does clearly state how to do this. This clearance MUST be checked BEFORE the rings are installed on the piston. Make sure you do it. Read the part on how to check them, it should make sense.

J-Mech · #78 03-01-2018, 10:13 AM

Quote:

Originally Posted by finsruskw

You do have a ring compressor I hope??

Lets not get too far ahead here..... he hasn't even gotten the parts checked and fit yet.

But yes, he will need to get one if he doesn't have one yet.
Hope he also has a torque wrench that reads inlbs and low ftlbs.

Joe_K · #79 03-01-2018, 10:13 AM

I use GM assembly lube on automotive engines.

J-Mech · #80 03-01-2018, 10:50 AM

Quote:

Originally Posted by Joe_K

I use GM assembly lube on automotive engines.

This isn't an automotive engine. It is a splash lube, air cooled engine. The safest, best recommendation is to use at most, a heavy engine oil, like maybe a 15w-40. I suggest just using the oil you plan to run in it. That way you don't buy multiple oils.