TD-20 seized bolts and screws

[OMCfan]

Picked up a free TD-20 and I have two head bolts and three exhaust manifold screws which are seized and I know this is not uncommon. Would it be a safe method to add heat on these bolts via a propane torch to try and loosen them up? I just do not want to bust them trying to get them off and I can't think of any other way to make a last attempt at this.

Thanks gentlemen!

 

[fhhuber]

A propane torch can get it hot enough to distort the aluminum...

Heat is a good idea but I would use extreme care. Aluminum expands more/faster than steel and I use that to remove pressed in bearings (and to just drop in the replacements without pressing) in very small engines by heating in my oven at 250 F. You really don't want to get things much hotter than 250 F and you definitely do not want to apply more heat to the bolt than to the block.

I'd try a hair dryer and a box to trap the heat... (since you probably don't want to try getting that block into the oven) Appliance stores are usually good about giving away used refrigerator boxes.

Note... it may be a good idea to cut the bolt heads off so you can get things apart... then the expanding aluminum won't be adding tension on the bolts.

 

[F_R]

Well I guess I take a different viewpoint. In my not so humble opinion after 24 years experience working on outboards in a salt water area, heat is the way to go. Not only that, a propane torch may not be enough heat. You need very hot, localized heat such as from an acetylene torch. But at the same time being careful not to melt it. The heat expands the aluminum around the bolt, loosening its grip on the bolt.

OK, realizing that is beyond the capabilities and skill of the average bear, heat still is the first line of attack. Won't hurt and may be enough to do the trick. Go for it. Mapp gas may be better than propane.

 

[HighTrim]

yeah, i agree F_R. Heat that puppy up with a torch. Propane will work, but as stated, the hotter Mapp or Acetylene is best. Heat, then hit with penetrating oil of your liking. Sometimes hot, then cold (upside down compressed air or can of COLD), then hot works.

 

[tommarvin]

Machine shops remove bolts, if you don't want too.

If heating doesn't work, you can drill them out, Cut bolt off 1/8 inch above block, get a center punch and tap the center of the bolt so the cobalt drill bit doesn't drift, start with 1/16 inch cobalt drill and slowly get larger you can try an easy out if it doesn't work just tap the hole for a Heli coil