My Tractor Forum banner
Cancel
Create thread New Forums

New to me Gravely L8

Jump to Latest
1 - 20 of 55 Posts
D

dealdan

· Registered
Joined
·
34 Posts
Discussion starter · #1 ·
I recently acquired a gravely L8. I was tinkering with it trying to work out all the little issues I found. I got the tractor running and I started noticing smoke coming from the exhaust. I pulled out the spark plug and found oil on the spark plug. So I proceeded with pulling off the engine head. Below are pictures of what I found

There is a lot of carbon build up on all the surfaces. The cylinder walls look good. No scratches or cracks that I can see. So to determine where the oil is coming from, what do you all think should be the next steps?

 
#2 ·
dealdan said:
I recently acquired a gravely L8. I was tinkering with it trying to work out all the little issues I found. I got the tractor running and I started noticing smoke coming from the exhaust. I pulled out the spark plug and found oil on the spark plug. So I proceeded with pulling off the engine head. Below are pictures of what I found

There is a lot of carbon build up on all the surfaces. The cylinder walls look good. No scratches or cracks that I can see. So to determine where the oil is coming from, what do you all think should be the next steps?

View attachment 2636874 View attachment 2636875
Click to expand...
If I had to guess , rings are worn .
 
Discussion starter · #4 ·
I guess my next question is, where can I find a good guide for how to rebuild the top end? I see a number of threads that get to the point of needing to rebuild the top end but I haven't found anyone yet that really does a good step by step with pictures. My issue is, not only have I never done anything like this on a gravely, I have never done anything like this on any engine. I've tinkered a lot with engines but never anything as major as this.

Can you all recommend some threads to look through or maybe a youtube channel?
 
#5 ·
dealdan said:
I guess my next question is, where can I find a good guide for how to rebuild the top end? I see a number of threads that get to the point of needing to rebuild the top end but I haven't found anyone yet that really does a good step by step with pictures. My issue is, not only have I never done anything like this on a gravely, I have never done anything like this on any engine. I've tinkered a lot with engines but never anything as major as this.

Can you all recommend some threads to look through or maybe a youtube channel?
Click to expand...
The old manuals are a good source of information.

GravelyManuals.com - OldGravelys.Info: Gravely Manuals & Parts Lists: Walk-Behind Tractors

chipmanuals.gtcoa.com
I would clean all the oil up and put the head back on run for 5-10 minutes and take the head off to see where the oil is coming from to plan your next move .
Have local machibe shop bore ,hone and gap rings address the valves and reassemble.
 
#6 ·
dealdan said:
I guess my next question is, where can I find a good guide for how to rebuild the top end? I see a number of threads that get to the point of needing to rebuild the top end but I haven't found anyone yet that really does a good step by step with pictures. My issue is, not only have I never done anything like this on a gravely, I have never done anything like this on any engine. I've tinkered a lot with engines but never anything as major as this.

Can you all recommend some threads to look through or maybe a youtube channel?
Click to expand...
I would also try to find a old service manual for that engine. My Kohler K321 rebuild went a lot better after I had the parts list and the service manual.
 
Save
Reply Quote Like Like
#7 ·
dealdan said:
I got the tractor running and I started noticing smoke coming from the exhaust.
Click to expand...
Very common, Clean up the carbon & reassemble. Most of the time after running it for about 10 hours the rings reseat and the oil burning stops or reduces to an acceptable level. Only then would I revisit the issue.
 
Discussion starter · #8 ·
Well I feel like every time I look at this machine I find more issues. I took the cylinder apart and found that the piston was badly scored at the top from the carbon build up around the rim of the cylinder. Additionally the piston ring gap measured in at about 0.037". It looked to me that the manual said they should be between 0.012"-0.020". I am waiting to receive a bore gauge so I can measure the cylinder bore and see where I'm at with that. I'm still hoping that the bore may be good enough so I don't have to get it rebored. I took the valves out and they had a lot of play in the valve stems and the valve surfaces were worn concave. The valve seats in the block still seemed okay.

To cap it all off, I noticed that at some point one of the exhaust port ears had gotten broken off and someone put a wood screw in to hold it on. So my parts list at this point is valves, valve guides, piston, piston rings, and maybe a new cylinder.

Anyone have any clever solutions for fixing the exhaust port ear? I'm not super confident in my brazing ability. It seems like a common issue but the threads I found just mentioned trying to find a new cylinder. Is the 7.6hp cylinder functionally the same? From what I can tell, the made a couple changes to the sealing surface of the head but all the dimensions were the same.
 
#9 ·
dealdan said:
Well I feel like every time I look at this machine I find more issues.
Click to expand...
Normal due to the abuse they are given.
dealdan said:
Is the 7.6hp cylinder functionally the same?
Click to expand...
Yes similar but the 7.6 is much beefier and better. At this point I would be purchasing a 7.6 jug since the ear will be a challenge to you. I would be reaching out to Rob of western MA, very reasonable.

Good luck!
 
Discussion starter · #10 ·
I started looking on Ebay at jugs but most of those ones seemed to be in similar or worse condition than mine. Who is Rob of wester MA? Does he have a business selling gravely parts or is he a private individual?
 
Discussion starter · #13 ·
Okay I'm torn. I have measured my cylinder using the ring gap method in the service manual (where you put a ring a half inch from the bottom and top) and I came out with 0.003". The service manual said that it needs rebored once that number gets to 0.006". I also measured the bore with a bore gauge and found that it was on the high side of within spec. I'm thinking then I should just try to fix the exhaust flange some how and then buy a new standard piston and piston rings. It seems a shame to scrap a cylinder that is in pretty darn good shape because of a broken ear.
 
#14 ·
dealdan said:
Okay I'm torn. I have measured my cylinder using the ring gap method in the service manual (where you put a ring a half inch from the bottom and top) and I came out with 0.003". The service manual said that it needs rebored once that number gets to 0.006". I also measured the bore with a bore gauge and found that it was on the high side of within spec. I'm thinking then I should just try to fix the exhaust flange some how and then buy a new standard piston and piston rings. It seems a shame to scrap a cylinder that is in pretty darn good shape because of a broken ear.
Click to expand...
You can't simply add new rings , they won't seal .
The cylinder needs to be round for new rings .
See thread below
 
Discussion starter · #16 ·
Okay I’ve been looking for the parts I need. I called Richard’s but the price for the parts was much more than I’d like to spend. The labor for the machine work I thought was very reasonable though.

I found an eBay seller called lil red barn power equipment supply that sells aftermarket parts. The cost is significantly less than trying to get oem parts. Does anyone have any experience with these aftermarket parts? I know you get what you pay for, but to be fair, I’m guessing oem prices are driven up by lack of supply.
 
#17 ·
dealdan said:
Okay I’ve been looking for the parts I need. I called Richard’s but the price for the parts was much more than I’d like to spend. The labor for the machine work I thought was very reasonable though.

I found an eBay seller called lil red barn power equipment supply that sells aftermarket parts. The cost is significantly less than trying to get oem parts. Does anyone have any experience with these aftermarket parts? I know you get what you pay for, but to be fair, I’m guessing oem prices are driven up by lack of supply.
Click to expand...
I'd call gtgravely , nothing listed but he may have some parts .
 
#18 ·
I've only bought parts from lil red barn through amazon (haven't installed/used them yet, bought a kind of rebuild kit for my Kohler CV23S from their amazon store), but they did botch my order. They sent me the wrong rings with my kit, and I happened to notice there was too much clearance between the rings and piston. They did send out the right rings when I told them about the problem.

So far, the only actual negative things about the experience w dealing with them are:
-the rings came with a generic sheet indicating how the rings should be oriented, depending on the profile of the ring. But there's nothing to indicate which ring should be on top and which should be the middle ring
-they repeatedly botched the name on the mailing label, so it was a hassle to pick up the package at the post office.
 
Discussion starter · #19 ·
Okay its been a bit but I finally assembled all the parts I needed. I ended up getting the piston and rings from lil red barn. The quality seemed good and I was able to figure out the ring orientation without too much trouble, though I do agree, the sheet was pretty generic. GT Gravely was able to supply the valves, valve guides, and gaskets.

I went back and forth on how to fix the exhaust. I considered a new cylinder, but the old one was in honestly really good condition and I hated to scrap a cylinder that was in such good shape. I also considered threading the exhaust port and making a custom exhaust manifold. This was doable for me, but it was quite a lot of work. I ended up building a jig to hold the cylinder in my mill, machined the surface flat and cut out a shelf for a block of steel that i then bolted to the cylinder. This ended up working really well. It is quite solid.

I also decided to replace the oil lines. One of them was crushed and so I replaced all the 1/4" ones. I got an air cleaner and got it mounted as well. I managed to get it all put back together today and it started right up. Unfortunately I didn't have oil pressure, but it was encouraging that it ran. It sounds like it might be a priming issue since I replaced all the oil lines and the oil filter. I decided it would be a good idea to inspect the oil pump and when I took it apart, I found it had no gasket. So I guess I have something else to order.

All in all, it is slowly coming back to life.
 

Attachments

#20 ·
A quick tutorial on priming your oil pump.

 
Save
Reply Quote Like Like
1 - 20 of 55 Posts
About this Discussion
54 Replies
10 Participants
Last post:
3/4-wrench
My Tractor Forum
posts
4.4M
members
246K
Since
2005
A family friendly forum community dedicated to all Tractor owners and enthusiasts. Come join the discussion about specifications, modifications, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
John Deere Forum Craftsman/Sears Forum Backyard Round Table: L & G Tractor Related Topics Introductions Walk Behind Mowers