Hi:

     I was gifted an older HP Gold Head .40 RC engine from the 70's or 80's today.  I would like to remove the head and backplate to check for rust debris etc.  This engine had been attached to a tool box in a garage for display sans the carb.  It may have a ton of dirt in the inside.  The screws fot the head and backplate are TIGHT.  I was thinking of soaking both the head and backplate in  penetrating oil and carefully attempt to remove the screws.  If this fails, can you say heat gun?  Is the backplate metal or plastic?
 SThank goodness screws have socket heads!

   Where ould I obtain a NVA and stunt venturi in case I get this engine to run?

   How would it be as a Stunt engine?

   What kind of heads do the screws have?

    Brett

after u have soaked everything ,take a flat punch the size of the screw head using a small hammer give each screw a sharp tap ,dont kill it  it will jar the threads and should come right out

last week had to take out some stripped phillop screws from a dooling29,they are recessed in the head if i can figure out how to post a picture i can show what it took to get them out

       Hi All:

       After having a bloody horrible time of removing the screws fron the HP I hit a snag.  Thirteen of the screws came out with much resistance! They cracked like a .22 when they broke loose.  Of course like any other project, all but one screw could be removed! I stripped the socket on the cap screw without budging it at all.  this was after soaking in penetrating oil, applying heat and striking the screw with a punch.  I have never seen such a small screw be so tight! I used my best Allen Keys for the job. Perhaps it is better to leave the p&c in place as  there is no rust to be seen! As far as I could seee, there was only rust on the crankshaft at the intake area.  I removed the rust and polished the rusty area.  I also removed the rust from the inside of the crankshaft.

     Now I can do two things: Leave the stripped screw in the head and attach the head with the other 5 screws or drill the head off of the damaged screw and HOPE that I can remove the remaing part of the screw by using pliers.  Of course I will need to find a replacement 3mm screw to replace the damaged one.

      This engine appears to be well constructed.  It looks like it has a Schurnle porting system, aluminum piston.and a forged rod that is bushed at both ends.  This is the first HP engine that I have seen.

     In any case,  does anybody have any suggestions as to what to do?

                                                                                                                         Tia,

                                                                                                                         Frank

I would simply drill out the head with the same diameter drill as the bolt shaft diameter. The head will then come off and you can remove the cylinder head. Then simply get a mole wrench or whatever you call it in the US (vise grip?) and undue the remainder of the bolt.
If you have a drill press, then it is an easy exercise. If not just take extra care.

Regards,

Andrew.

First, useless ('cause the socket's already stripped), and maybe something you already know: if you're removing a bunch of bolts from something and one is particularly troublesome, put all the other ones back in nice and tight and try the bad one.

Second, I have heard from old mechanics that a solution of alum and water will dissolve steel but not aluminum.  It's a specific remedy for steel fasteners that are stuck in aluminum parts.  So if you drill out the bolt and can't get the stub out, there's still hope.

Third, I never give up on a stuck fastener until I've let it soak in penetrating oil for at least a week.  So if you do drill it out and it doesn't come out immediately, drench it with oil and let it sit for a good long time.

Forth, another tidbit I've heard from old mechanics is that not all penetrating oils are equal -- whenever the subject comes up on the metalworking newsgroup I hang out in, Kroil gets mentioned.

Fifth, if you do drill and wrench on the stub, head the end of the bolt up with a soldering iron and quench it in water, maybe a few times.  If you're lucky, that'll heat-shock whatever gunk is holding stuff together.

Sixth -- I guaren no tees here.  You may try all of this and still have it fail.

Hi Frank,
If you get as far as drilling out the hex head and removing the cylinder head, the stub should come out easily. I said then use a vise grip, but that is way overkill. In the highly unlikely event that it won't come out, then don't try to force it! Simply hit the stub with a small propane torch (the type jewellers use). Get the stub cherry red and allow to cool and then try again. This has never failed me. Your description of the bolts clicking loudly as they give up the struggle indicates to me that they have been way over tightened. I will bet you a five spot, that once you drill out the bolt and remove the head, then the stub will come out with finger and thumb.
The previous advice of using a punch on the bolt is also an excellent way of loosening the bolt. Try that first!

Andrew.

My vast experience of removing stuck bolts tells me use liquid wrench to soak it in over night. Then heat bolt and tap squarely on the head several times and then try to loosen it. You could also put it in the oven for a while to make the case expand and it should come out easy.