corroded/rusted in head bolts ....

[orlandoclippertim]

I have a early 1960's evinrude 28 horse 2 cyl. The lower cylinder ( I think ) is stuck from possibly a bad head gasket - water in cylinsers.
I have been soaking clys in PB for 3 weeks with no luck. Removed head bolts to remove head. The bolt pattern is shaped like a pea-nut.
all the preeimeter ones came out OK but all had some white corrosion and a little rust. There are 2 in the "waist" of the pea-nut whichseem to be stuck MUCH harder. One of these I have acess to the area where the threads are - that is the back side of the threaded area is open. I have been shooting PB in there for about a week. No perceptable letup in torque. The other stuck bolt is in the area behind the water side plate cover.
I have taken most of the little #10 side plate bolts off thinking I might have acess to the bottom of the head bolt from in there maybe. However
2 of the #10 cover bolts are also stuck. Tried tapping with little hammer, heating , PB over and over.

The head bolts appear to be 5/16 grade 8. I can feel I am not moving the bolt- only "springing" the shank. I don't want to risk any more torque than I have tried. Will an impact type driver be OK - the kind you hit with a hammer ? I have tried a pneumatic air hammer without much effect.
I used small propane to heat head bolts. Lots of metal to soak up heat. May have to go to oxy-acet. to get bolt hot.

I have browsed search results but found nothing earth shattering in the way of ideas.

Any advice ?

Tim

 

[Haffiman]

Re: corroded/rusted in head bolts ....

Bigger propane torch, but not on the bolt but on the cast alu!!

 

[F_R]

Re: corroded/rusted in head bolts ....

If you have an oxy-acet, why are you dinking around with a propane torch? Heat the amuminum very hot, localized around the stuck bolt and use that pneumatic wrench to zip it out. By "very hot", I mean short of melting it.

Disclaimer: In spite of the best tools, we all break one off sometimes. That is why they make Heli-coils. BTW, it probably does not have Grade-8 bolts unless somebody has changed them--a good thing in case you have to drill them.

 

[1946Zephyr]

Re: corroded/rusted in head bolts ....

Well, if water has been in the lower cylinder, then there's a good chance your powerhead is shot anyway. Don't get to distressed over a couple broken bolts.

 

[orlandoclippertim]

Re: corroded/rusted in head bolts ....

the idea was to heat the bolt head and let the heat conduct down the 3 or 4 inch bolt to the threaded part. I won't be attempting to turn it out untill it is back to room tempature as aluminum has drasticly less strength above 200 degrees F. I can try heating the aluminum block where the thread is but I can only get to 1 of the 2 to do that. There is something in me that won't let me tear up something just because its allready broken ...... fixing something so it cant be fixed .... as we all have see somewhere sometime.
I guess the rust is making the steel rough and the corrosion is making the aluminum rough and they meet in the middle to cause extra torque.

will keep trying.
T

 

[Haffiman]

Re: corroded/rusted in head bolts ....

Heat the bolt and it expands and gets more stuck.
Heat the surrounding casting, it will normally expand and loosen the grip, the oxidation gets softened and the bolt may get out.
I have never used Acy-Ox on any alu part, propane has been enough! If using Acy-Ox, get a heat gun and check the temp. Do not go above 250C!! (480F)

 

[Mas]

Re: corroded/rusted in head bolts ....

You can always grind the hex heads off the bolts, tap on the cylinder head with a mallet to remove, then use more aggressive heat/vise grips to remove the bolts by the shank. Since you have an ace. torch, you can also weld a hex head back on the bolt for removal once the shank is exposed. The heat from the ace. torch should help with removal once cooled.

Mas

 

[FFScott6]

Re: corroded/rusted in head bolts ....

How's it going??? I had the same problem on my Gale motor (1960 60hp v4) 9 bolts loose and the 10th well it did break off...flush. Lots of patience. I knew better about heatting the surrounding metal but did not do it. then an easy out snapped deep inside. a $10 dremel like tool finally got things going for me.

Good luck.

 

[orlandoclippertim]

Re: corroded/rusted in head bolts ....

I have to try oxy-acetylene next. The little propane is not enough heat vollume. All that aluminum. I need to get the threaded area up to 400-500 F and that aint happening with propane. Just like welding thick aluminum - you have to dump a LOT of heat in in a short time to get a small area hot and not heat up everywhere else . I have broken off bits and easyouts. Then - if you can't get them out they are too hard to drill out. I have found easy outs are generaly a waste of time. I will try some more in the next couple of days. I'm sure its just aluminum oxide packed in there from corrosion. Would have been nice if they had been helicored from the factory like aluminum car blocks. Oh well- I have learned not to get in a hurry in these types of things.
Tim