My Tractor Forum banner
21 - 40 of 84 Posts

· Registered
Joined
·
503 Posts
Thanks for the tips from you both.

How do I determine if the valves need anything?

I’ll clean up the piston and get better pics. Assuming I need a new piston, is gtgravely the best place?
GT Gravely is good. Or Richards Lawn and Garden is another go to place. As well as Jacks is another place I check and get a price from.
 

· Premium Member
Joined
·
5,926 Posts
How do I determine if the valves need anything?
I usually just eyeball them, unless I have a reason to think there's something busted. Since the jug is off, it's easy to get a valve spring compressor on there and take off the keepers, then slide them out. Just inspect the valve where it hits the seat, and the seat itself. (Note that on this engine there is no seat per se, just a milled area in the casting). If both are smooth and clean looking, I look no further and button it back up.

If you see rough areas, especially on the seat, you may need to do a bit of grinding.

But this engine was running, correct? So it can't be too bad.
Assuming I need a new piston, is gtgravely the best place?
Probably. I dunno who has good prices these days (it's been a few years since I bought a piston) but GT certainly is a plausible option.

Once you get that piston cleaned up, mic it too. Looking again at that pic, it's pretty funny. There's what looks like holes and gouges in there, but if that's just dirt, and the it mics out ok, I might retract my comment about replacing it. If it turns out that all you have to deal with are those faint gouges toward the top, you should be able to dress those out with a very fine file, and keep using it.
 
  • Like
Reactions: kyavion

· Premium Member
I use scissors! Twice a week.
Joined
·
11,008 Posts
That valve spring compressor probably won't work, as the valves are in the block, so you don't have the clearance on the spring end that that particular tool needs. You probably need something more specific/custom for that particular block.
 

· Premium Member
Joined
·
5,926 Posts
Actually, I think that tool might work. Since the jug is off, you've got all kinds of room on both ends.

The two questions I have, looking at that are:

1. What's the dimension inside the C clamp body? You probably need 8-9 inches because the valves are moderately long, and you need room for whatever screw thing goes in there.

2. What's it got on the other end? I couldn't tell from the pic. You need something with a sort of cup-like arrangement to push on the spring retainer, with a hole in the side so you can get the keeper out.

The one I use for this job is different. It's a sort of lever arrangement, with a handle the you push to close it up. It does have a screw adjustment, but only to get the size roughly right. It's not exactly like this one, but similar


There's no problem re-using the piston pin clips.
 

· Registered
Joined
·
711 Posts
Discussion Starter · #27 ·
Just looking around. Would something like this work as well?


or

[
 

· Premium Member
Joined
·
5,926 Posts
No, you don't want one for OHV engines, you want something suitable for a flathead.
 

· Registered
Joined
·
711 Posts
Discussion Starter · #31 · (Edited)
Thanks for sharing that link. Not that I intend to be being doing this much in the future, but would the Briggs tool I posted allow valve removal without the jug being taken off? Also, I dont mind spending a little extra if there’s a tool that would work for both this c-8 engine and my CCKA down the road.
 

· Registered
Joined
·
173 Posts
you don't need anything fancy to remove OPE valve springs this is what i use works for flat head and ohv
https://www.amazon.com/Lisle-23300-...lve+spring+compressors&qid=1672664342&sr=8-15
Been using one similar to this on B&S, Wiscy, Kohler and Gravely since 1972.

The carbon on the intake side, is it like a caramelized grit? I recall seeing this type carbon on low volume oil pump engines. A little unusual and would prompt me today to look for a cause.

The carbon on the exhaust side is normal.

Need to find root cause of the poor burn.

Just an observation.
 

· Premium Member
Joined
·
5,926 Posts
The one in post 30 will work fine. I don't see how the one in post 29 works.

Note that it'd be difficult to remove the valves with the jug in place. You need something which will reach in through the little door on the valve cover/tower/whatever thingie, and still have enough travel to pick up the spring enough to get the keeper off. RI (or anybody) have you successfully done it that way? I always take the jug off first . . .
 

· Registered
Joined
·
173 Posts
You need something which will reach in through the little door on the valve cover/tower/whatever thingie, and still have enough travel to pick up the spring enough to get the keeper off. RI (or anybody) have you successfully done it that way
Yes I have removed valves with the jug in place. You might have to remove the carb or be adjacent to the exhaust manifold and muscling the tool in, but it can be done. Poke the keepers with a small screwdriver to loosen & then use a small magnet to retrieve.
This what I use:
Bumper Rectangle Automotive exterior Bicycle part Gas


Tire Wheel Automotive tire Synthetic rubber Tread
 

· Registered
Joined
·
711 Posts
Discussion Starter · #35 · (Edited)
@RI-GravelyMod - You had asked if the carbon was like a caramelized grit. It’s a very fine grit, but I would not say it’s sticky or caramelized.

@jrd - You had asked earlier if this was a running machine. Yes, it is a new to me machine, and it seemed to be running fine. That said, I haven’t used it much—just a couple times to mulch up some leaves. I just lifted the head to replace the gasket since I’m not using it right now. Nothing was wrong with the existing gasket.

So I wiped down the piston. There appear to be some scratches as seen in these pics, but I can’t feel anything unless I use my fingernail across them. Those vertical streaks cannot be felt. It’s the small indents that can be felt if I drag a nail across them.

Automotive lighting Headgear Automotive tire Auto part Personal protective equipment


Light Automotive tire Gas Automotive wheel system Auto part


Automotive tire Drinkware Fluid Gas Auto part


Automotive tire Gas Automotive wheel system Auto part Machine


Below are pics of the valves. I don’t really know what I’m looking for, but they appear seated ok. The shadows make one side seem high in the pics
Wheel Tire Automotive tire Tread Locking hubs


Wheel Tire Automotive tire Product Locking hubs


Tire Automotive tire Tread Automotive design Wheel


Tire Wheel Automotive tire Motor vehicle Product



Below are a couple pics of the cylinder. I haven’t honed it yet. It’s rough on the end as seen in the pic, and on that same end the lip is a bit sharp. The other end of the cylinder is smooth as can be. When I hone, I assume I should get all that smoothed out?

Automotive tire Fluid Rim Automotive exhaust Automotive wheel system


White Automotive tire Light Synthetic rubber Automotive wheel system
 

· Premium Member
Joined
·
5,926 Posts
That's not the worst scoring I've seen, by a long shot. But it's not pretty. I'd say somebody ran that machine a while very low on oil.

The piston looks much better that the earlier pic, that must have been dirt/oil on there.

Cheapest fix: Put new rings in, put it all back together, pretend you never saw it, and use the machine for the next 10 years :)

I suspect you don't want to go that cheap. In that case, mic it first, to see how worn it is. If it's within spec, or even close to it, hone it, in particular the top of the bore where the scoring is worst. I wouldn't try for a glass smooth finish, just clean enough that when you run your fingernail over it it doesn't feel rough. Replace piston and rings.

The really correct fix, it's it's worn past spec, would be to bore it. Then hone, new piston etc.

If it was my machine, and it had been running beforehand, I'd try to go for the cheap fix.

[Later] Actually, that's not quite right. I'd hone it to remove the rough stuff, esp at the top. And I would mic it. But I don't believe it's too far out, based on that marks on the piston and jug. So if it mic'ed out reasonably ok, I'd just hone it and put rings in it and be done with it.
 

· Premium Member
I use scissors! Twice a week.
Joined
·
11,008 Posts
You can't really tell what state the valves are in, just looking at them when they are installed. You need to at least open the valves enough to see the mating surface on the valve and the valve seat, to see if there is any carbon buildup holding it open just a bit, or corrosion/wear so it leaks a bit.
 
21 - 40 of 84 Posts
Top