LawnBoy Engine dismantling, cleanup and rebuild #2

[Russ2251]

I'll give the 300 stuff a shot and see how it holds up for me. If the same thing happens that happened to you, I'll check for uniformity

Will be much easier to do this when engine is disassembled.
Trust me.
Available here:
http://www1.mscdirect.com/cgi/nnsrhm

 

[kibble]

more to get! I tried to get it but it said they were sold out. Can't I just get lapping stuff at the auto store that'll do the same thing?

Oh, today I went to a power equipment rental place out a ways from where I live, it's the first place I shoulda gone to begin with! They have use parts and stuff up the wazoo! When I explained to the lady that I had a LB engine I was fixing up to use on my kart, she said: "Oh! I have a go kart too!" and took me around the lot and showed me what she had. she was running a Tecumseh motor on a small kart with a t.c. She says she gets up to about 45mph.

Anyway, I was gonna take the carb I have for the pressure washer and see if she can find me a similar sized, adjustable one.

I received the 300 today and the fuel line. I'm still waiting on the seals and now that you told me I should lap it, I have to get something to do it with too. Oh, and I took the HL239B apart because I had a feeling it was dirty inside...it was. So I'm gonna have to clean that too.

 

[Russ2251]

When I explained to the lady...

Was she good lookin'? If so, give me her number.

Can't I just get lapping stuff at the auto store that'll do the same thing?

Yes, I was just pointing out what I use. 320 grit is what works, so shoot for that.

 

[kibble]

Was she good lookin'?

NO!!!!! But she IS nice!

Ok, I'll go look for some compound.

 

[Russ2251]

Took a 40 minute run today with zero head leakage. Very promising. I could smell excess Permatex '300' burning off.
Smells like a cross between rotting slug carcasses and a chocolate latté.
Yum...I think I'll cook some up and make soup.
Care to join me ladies?

 

[kibble]

Smells like a cross between rotting slug carcasses and a chocolate latté.
Yum...I think I'll cook some up and make soup.
Care to join me ladies?

I got the lapping compound today. I'll be lapping the head this weekend hopefully and putting the thing back together! I'm still waiting on the PTO side oil seal, however.

Oh yeah, and I did notice on the repair manual that it says to use some stuff on the oil seal and make sure there's no oil in it when you put it in to avoid blowing out the seal. What do you recommend?

 

[Russ2251]

What do you recommend?

Do exactly what they say. No probs here.

 

[kibble]

That's just the thing, it doesn't name anything, it just says: "Use some type of seal protector to prevent damage to
the seal lip and slide the seal down the crankshaft."

Can I just put a thin coating of some lubricant on the shaft to prevent it from being damaged on the way in? there's nothing much on the shaft to damage it in the first place.

I'm wondering if you have a different manual than I have.

 

[Russ2251]

I'm wondering if you have a different manual than I have.

No different. Only 1 manual which covers DuraForce (Lawn-Boy) and R*Tek (Briggs & Stratton).

Can I just put a thin coating of some lubricant on the shaft to prevent it from being damaged on the way in?

Yes, any oil will do.

About seals:
On older model engines (non DuraForce) it was OK to press in seals once crankcase was assembled.
This is NOT OK on DuraForce. Seals should be assembled onto shaft and then nestled into crankcase half as shown in figure #85. Eyeball seals to make sure they are straight and not canted or tilted in seal bore. This is stated in manual and is important.
Also, I smear a very thin coat of Loctite #515 around circumference of seals.
I do this because we are forcing these engines to 'jump through hoops' as opposed to cutting grass. I have no doubt that crankcase pressures are above the grass cutting norm.

 

[Russ2251]

Mr. Kibble:
Out of curiosity, what is top ring shape (cross section)? Are rings pinned?

 

[newrider3]

Oh, today I went to a power equipment rental place out a ways from where I live, it's the first place I shoulda gone to begin with! They have use parts and stuff up the wazoo!

Equipment rental shops FTW. My local has an entire shop filled with old engines and machines, mostly Hondas and I/C Briggs. Got my project engine from them for about $30.

 

[kibble]

The top ring is the semi-keystone one. Yes I put it in correctly. :arf:

By pinned, you mean they have that area for the pin on the piston? If so, yes.

 

[kibble]

Equipment rental shops FTW. My local has an entire shop filled with old engines and machines, mostly Hondas and I/C Briggs. Got my project engine from them for about $30.

Sweet!

 

[Russ2251]

The top ring is the semi-keystone one. Yes I put it in correctly.

I asked because one of my engines has standard ring and other is semi-keystone. All else are identical between the 2 engines.

 

[kibble]

Some updated pics of stuff I did this weekend. I applied the super 300 to the head and torqued it to specs. Cleaned the carb, I took several "before/after" pics. The one on the left is what the one on the right looked like before I cleaned it. Then I have several pics of what the air cleaner carb and crankcase look like assembled. I received the PTO side oil seal today so I'll be putting the rest of it together soon.

 

[Russ2251]

Excellent...Nice work señor Kibble. You get the Golden Piston Ring.
Any high/low spots on head sealing surfaces that you could detect?

 

[kibble]

You know, oddly enough, the area around the head that was on the same side as the exhaust seemed to be the most uneven. I used the compound stuff until it seemed to be pretty even all throughout. I put a light coat of the super 300 with the brush with the bristles going all in one direction, then I went over it in the opposite direction to make a bit of a crosshatch pattern on the material to hopefully help spread it out evenly.

 

[Russ2251]

oddly enough, the area around the head that was on the same side as the exhaust seemed to be the most uneven.

Now I'm very curious as to condition of my 2nd DuraForce as well as both Briggs 2 cycles (R*Tek).
Would be really bizarre if all these engines exhibited this same low (uneven) spot.
Can't expect engine manufacturers to lap cylinders and heads as it would not be cost effective.
Gaskets are cheap...lapping is much more expensive by comparison.

 

[kibble]

No doubt!

I put together the cylinder and crankcase. It's almost ready to roll!!!

 

[Russ2251]

Cool