I have an old Irvine marine .61 engine that needs some cleaning. However I can't loosen the screws on the head. The screws are an allen head and the just won't budge. What should I do?

Try warming the engine with a heat gun for a bit and try again. Also make sure that you have the correct wrench to use. Don't ask me how I know this is important!

ZB

You can try using penetrating oil on the screw. Make sure you don't get any inside the cylinder, or at least don't turn the crank if oil does get in. You may also find using the "anti-freeze in a crock pot" method to clean the engine will also loosen the screws, as a combination of the cleaning/heating action.

As a last resort, you can drill the head off the screw. Be real careful not to drill too deep and damage the head.

Nate,

Heat might work to loosen the head bolts.
However, since Aluminium expands more than steel, the bolts may be significantly tighter, if you try to open them while the head is hot.

Your engine has what I believe to be Metric bolt sizes. An imperial (inch) Allen wrench will not fit, and potentially could destroy the sockets. Take notice!

Shoe:

Another trick that often works for me is using a steel punch that fits INSIDE the socket of the screw, strike it sharply with a hammer while supporting the engine on metal bars under the mounting lugs.

This tends to stretch the screw, and often works when nothing else will.

Bill.

Well, I have tried wd-40 to loosen them up a bit, did not work. Tried heating it with a heat gun, did not work. I do have a metric wrench and it is for sure the right size, it hasn't slipped yet in all my failed attempts. If the steel punch thing doesn't work then I'll probably just have to drill them out, eh?

Why not?

Use a Dremel wheel and cut a slot in each bolt, then use a flat-head screwdriver... worked for me!

Well razor the problem with that is that the screws are recessed. Mr. Robinson your idea worked on the first two(still required all my strength and a little gripper thingy) The the head of the driver broke off on the third one. So it looks like I'm going to have to drill 'em out. Unless someone has a different idea?

Shoe:

Grind the end of the driver down to a fresh hex section and keep going. Might need to whack the screws once or twice more.

Bill.

I've used this tool for 30 years.

http://www.sears.com/sr/javasr/produ...cemgdffmdfko.0

The driver will fit all your common 3/8 (and 1/4 drive stuff with a standard adaptor)
Grab your Dremel "cut off" wheel attachment and cut off a one inch lenght of Allen
wrench of the correct size, and insert into a suitable six point socket.( One wrap of electical
tape at one end before inserting will give it a snug fit if you like.)

Just a couple rather light taps on this small stuff an out she"ll come :-)

If a small enough socket is unavalable, Sears also sells special "Allen" wrench sockets.
Also Harbour Freight sells simalar stuff of questionable quality for "once in a blue moon"
use.

Had the same problem a while back. I put the engine in the freezer and allowed to chill... then I took a torch and working quickly heated the cylinder only around the bolt bosses while making every effort not to allow the head to get to much heat...the bolts came out just fine then. Worked for me.

I mounted the engine in a drill press vice and put the stub of a socket head wrench (about 1") in the drill press chuck. I lowered the spindle and the wrench into the socket head bolt, and added moderate downward pressure. I then slowly turned the chuck by hand just enough to loosen the bolt. (It goes without saying, the switch to the drill press was not turned on.) I found this useful in removing phillips head screws also. To get a good grip on the chuck, I inserted the chuck key for leverage.
Good luck,
Cajuncharley

I/ve used this method before and often seems to work.

Using a "T" allen wrench ( an "L shape works too), Insert the allen wrench into the screw head and while you are turning have someone tap on the end of the wrench. Do be afraid to rap it pretty good. Sort of acts like a impact driver. Be sure to have the engine lugs resting on a solid surface, like the top of vice jaws.