blown gasket?

[debriscreator]

i started taking my hs40 apart to get it ready for sand blasting... and i noticed that there is a lot of black stuff near one of the corners of the head/block.. also noticed that the head bolt on that corner was covered in oil. is that a sign of a blown gasket? or something worse...? inquiring minds would like to know.. here is a pic. thanks in advance. - dave

 

[debriscreator]

ok i went in deeper to see if i could figure it out for myself.. took the head off and i took some pics. the head gasket didn't look bad but there was oil near the edge where the oily bolt was. i cleaned it up a little but it's the corner where my finger is pointing on the picture. there is also a lot of carbon build up on the head and on the valves. what's a good way of cleaning this up without messing up the timing or causing the engine not to work anymore. do i need to buy a new gasket? also is it a good idea to clean the piston? what is a safe way to clean it.. thanks again - dave

 

[mmisterbungl]

your head may not have been properly torqued:shrug:
Are you really going to sandblast, or bead blast?

Mineral spirits works good for cleaning carbon deposits.

 

[Jeff Clark]

Stick it in the solvent tank and get busy.

 

[debriscreator]

yes i'm going to sand blast it.. i make sure none of the orifices are exposed.. stick plastic in holes and duck tape around them. if it wasn't torqued correctly.. does that mean i have a blown gasket now or is something bent/cracked or warped? what kinda solvent jeff? and what do you mean by get busy? sorry i'm not very experienced with engine work.. as you can probably already tell. :laugh:

 

[125ccCrazy]

You will have to use a straight edge and feeler guages to check to see if the block is warped...The head you can run over a flat surface like the top of a steel table saw or a thick piece of flat glass with some sandpaper on the surface...or a nice flat piece of sandstone...This will show high and low spots...
Chances are the gasket just deteriorated over time and was seeping, very common and useually doesn't result in any warpage..

I'd spray the block with Purple Power degreaser and scrub it down good, inside and out (I assume your rebuilding it) before any blasting..

I personally blast my blocks also...I'll bolt the head, side cover, valve cover ect on the engine...leave the sparkplug in the head and blast away... Then wash and wash and wash with degreaser again until it's sparkly clean inside... Blow everything out real well with an airhose also...

If you don't get all the grease and gook off and out of the engine the media will stick to it and you'll have more work in the finaly cleaning... I'd also hone it and grind the valves before blasting and cleaning since you'll have residue from both those procedures that will need cleaned out..

 

[Tom S.]

You will have to use a straight edge and feeler guages to check to see if the block is warped.....

 

[Tom S.]

...The head you can run over a flat surface like the top of a steel table saw or a thick piece of flat glass with some sandpaper on the surface...or a nice flat piece of sandstone...This will show high and low spots...

Wet-dry sandpaper moistened w/some WD40 works good, and use a figure-8 motion to ensure an even cut. Coat the gasket surface first w/black magic marker. After making just one or two passes the high spots will become visible as the ink is sanded off. Repeat the process until all the ink comes off at once and then you'll know it's flat.

 

[125ccCrazy]

Visual aid helps alot...:thumbsup: Good pics Tom

 

[Motra]

This is what "gettin' busy" in the solvent tank is. Solvent in an industrial parts cleaner and you use it in a tank that recirculates and filters it and pumps it out through a brush.

 

[Oldsalt]

ok i went in deeper to see if i could figure it out for myself.. took the head off and i took some pics. the head gasket didn't look bad but there was oil near the edge where the oily bolt was. i cleaned it up a little but it's the corner where my finger is pointing on the picture. there is also a lot of carbon build up on the head and on the valves. what's a good way of cleaning this up without messing up the timing or causing the engine not to work anymore. do i need to buy a new gasket? also is it a good idea to clean the piston? what is a safe way to clean it.. thanks again - dave

By you pics of the block surface and the head gasket I believe you had a head gasket leak that went from the combustion chamber to the stud that was 'oily'. It was probably there for a long time and did not get worse. As said above, clean it up and put it back together with a new head gasket carefully torqued to factory specs. After the engine has been heated up and cooled a couple of times recheck the torque...all will be fine.

 

[george3]

Make sure that engine is compleatly sealed before you blast it.