Engine Cleaning Gone Wrong

[gonzegorch]

I stripped my third gear at the weekend. so whilst i was removing this i thought it would be good to take the engine apart and do some maintance only to my horror. i now have a usless engine. the screw on the end of the crank shaft snapped leaving about 4mm of the screw still in there and i tryed removing the crank shaft cover at the back i got 3 of the screws out. but the previous owner has spun the fourth screw. basically i don't have much spare cash. so can anyone please tell me the cheapest way i can get up and running again. i can post pictures if this helps. I'm in the UK.

 

[Dreadnaught]

post some pics. that will help alot. what engine is it?

 

[gonzegorch]

the engine is a F4.6 i will post pictures tomorrow as camara is at work.

 

[Dreadnaught]

you may be able to pick up another one cheap off dabay. maybe get one that has the parts you need, but isnt running.

 

[Larsenracing]

If you heat the end of the crank you should be able to get the screw out using a pick or a chizle.

As far as the screw on rear of engine, is it the backplate with the rolo start or is it the aluminum plate that seals the rear end?

 

[nickmind]

The screw on the end of the crank shaft snapped leaving about 4mm of the screw still in there

Unless some one else on here has a magical way of getting that screw out. You will at minimum have to replace the shaft. But if you can get maybe 6 or 7 threads of a screw into the shaft. You can cut a screw to size and use loctite for a temporary fix. You maybe able to get away with less threads. It is only holding the flywheel bearings in place, not much force on that screw.

and i tryed removing the crank shaft cover at the back i got 3 of the screws out. but the previous owner has spun the fourth screw. basically i don't have much spare cash. so can anyone please tell me the cheapest way i can get up and running again. i can post pictures if this helps. I'm in the UK.

You can find a "tap and removal screw kit" from a hardware store to get the screw out. But that kit cost me $20. Or you can do what I have done in the past. Use a dremal with a cutting wheel and cut a flat line in the screw so you can use a flathead screw driver to get the screw out.

 

[gonzegorch]

it is the aluminum plate that seals the rear end. the screw on the crank shaft is just in a tiny bit to far down to cut the end without damaging the shaft and is too near the top to secure another screw. i'm guessing both screws have been placed in with lock tight. does heat effect lock tight. would putting the engine in the oven loosen the lock tight.

 

[Larsenracing]

Heat will soften or make the lock tite loose its hold whale its hot. To get the back out you will also need to use a chisel and a small hammer and hit the head of the screw in a counter clock wise direction. This will get it out. You can do the same on the one in the front of the crank but will need a very small chisel or screw driver as the screw is small. It will come out. If you were closer I'd say ship it to me. There is no guarantee that it will work but it should.

 

[Jeremy]

Someone might have a crank for the f4.6 .. Ask in the WANTED fourm ..

 

[Grumpy1822]

Use a dremmel to cut the crank flush with the threads. Then use this. Its a fix that Icow posted on the other site.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXBZT0&P=7

 

[gonzegorch]

A freind came to my rescue. he works at an engineering plant, he milled the broken screw out of the shaft and spot welded an allen key to the round off screw at the back. So now i have another question, if i don't use lock tight to refit the screws is this bad? just that lock tight has caused all the problems i have had. and what is "Associated's Green Slime " and lastly how does Permatex Utra Copper dry? does it go hard, so if i got it on a screw thread will it lock the screw in and can i still take the engine apart again with ease after using Permatex Utra Copper to seal it? Thank you all for your help :jamout:

 

[Blazer X]

You will need to loctite that screw in. I have made that mistake twice and it didnt take long for the it to come apart. Just make sure to use blue or even the the light green loctite for small screws under 3/8". Any RTV sealer drys to a soft gel, it will be be removeable without a doubt.

 

[Grumpy1822]

I never use locktite in the crank. You just have to know when tight is tight. I do use locktite in the backplate.

 

[nickmind]

A freind came to my rescue. he works at an engineering plant, he milled the broken screw out of the shaft and spot welded an allen key to the round off screw at the back. So now i have another question, if i don't use lock tight to refit the screws is this bad? just that lock tight has caused all the problems i have had. and what is "Associated's Green Slime " and lastly how does Permatex Utra Copper dry? does it go hard, so if i got it on a screw thread will it lock the screw in and can i still take the engine apart again with ease after using Permatex Utra Copper to seal it? Thank you all for your help :jamout:

You got the right Idea. The only place I use loctite are on the head screws only (only 1 or 2mm on the endof the screw) of the I don't use anything in the crack screw maybe a little Permatex, and use Permatex Utra Copper for the backplate screws. Don't use loctite on the backplate screws. This has bit me 3 times now. I needed to learn my lesson sooner or later.

As far as permatex, It seals. That means any gaps will be filled with a copper sealint. This makes the screws not vibrate which prevents them from moving. As well with holding the screws a bit. The problem with loctite is the heating and cooling of the engine. So when you go to unscrew you HAVE to make sure you HEAT the engine before. Or we have this problem. So thats way I am using permatex from now on. I've use it on two engine so far, and after maybe 20 runs no issues.

My thing is this, I am always rebuilding my engines after every 2 to 3 gallons. So loctiteing them is becoming a problem more and more.

How I use it is this, I fill the hole first with Permatex. Using a tooth pick or something like. Then use some Permatex on the back of the screw. Then screw down tite. You should be fine.

 

[XxxNate's SavagexxX]

hey i got an f 4.6(runs) NOT THE ONE THAT ATE SAND!!! just needs a carb and silver sleeve any offer! hell you can have it!!

 

[AllanQ]

Send it this way Nate. Pm me paypal or how you want me to pay for shipping, I'll send back my address.


Mods/Admin appologize for gettting off topic.

 

[Grumpy1822]

When instaliing the backplate use good screws. The 12.9 ones that come in most quality screw kits. Use blue locktite. Not red and use just a drop on the tip of each screw. Most people seem to go overboard with locktite. As far as ultra copper, its no better than reg old black. Ultra copper is made for high heat water sealing. Head gaskets and water jackets. Th plain old black for $5 will do just as well on nitro engines. If you really want nitro proof then get the racers edge stuff for $10.