Lawn Boy engine #2

[Russ2251]

Update: Head gasket removal/Flange sealant

I test ran my DuraForce a few more times and discovered that Hylomar sealant has developed some leaks.
I disassembled it, cleaned it up and reapplied Hylomar to both surfaces this time and torqued to maximum factory spec of 200 inch pounds.
It still blew out. Why this is happening is unknown to me at this time. I used to do this procedure on McCullough kart engines which had much higher compression pressures (required external starter, no recoil) and never had any problems.
I cleaned it up again and am now experimenting with Loctite #515 which is an anaerobic sealant. Meaning it cures because of lack of oxygen. The Hylomar does not cure and remains gooey.
So far the Loctite is holding.

 

[Kenny_McCormic]

I test ran my DuraForce a few more times and discovered that Hylomar sealant has developed some leaks.
I disassembled it, cleaned it up and reapplied Hylomar to both surfaces this time and torqued to maximum factory spec of 200 inch pounds.
It still blew out. Why this is happening is unknown to me at this time. I used to do this procedure on McCullough kart engines which had much higher compression pressures (required external starter, no recoil) and never had any problems.
I cleaned it up again and am now experimenting with Loctite #515 which is an anaerobic sealant. Meaning it cures because of lack of oxygen. The Hylomar does not cure and remains gooey.
So far the Loctite is holding.

Rougher surfaces on the dura force head/jug?

 

[Russ2251]

No.

 

[Kenny_McCormic]

Weird.

 

[Russ2251]

Update: Head gasket removal/Flange sealant (cont.)

I have determined that Hylomar is not an acceptable sealant as it has failed me on 2 test runs.
I switched to Loctite #515 which seems to provide a more solid seal. I test ran engine at 4000 rpm for 20 minutes (no load) and did not leak. Next test will be under a full load.

 

[Kenny_McCormic]

According the the loc tite catalog #518 would work better.

 

[Russ2251]

If 515 fails will try 518, Thanx.
Spoke to one of my 'old' karting buddies and agreed that Hylomar should have worked. He is a metallurgist for a local plater and indicated that some sealants may be incompatible with my particular application.
He compared it to trying to paint wax paper. Well...maybe.

 

[ironman]

russ how is that 515 doing is it holding had any leaks out of it yet?

 

[Russ2251]

how is that 515 doing is it holding had any leaks out of it yet?

Working out perfectly. About 2 hours total run time and zero leaks.
I will soon pop head off and make complete evaluation.