buzzingb

My Feedback: (2)

Well now that I know there is a hole in the pin I think I will add one more idea. If you take a dry wooden dowell about the size of the hole use a belt sander or grinder let is spin and sand away wood till it will just go in hole of wrist pin. Place the wooden dowel in pin hole use antifreeze and start soaking the wooden dowel and let it swell over night. It will swell up to the point the pin will come out or the dowel will break. Anyway worth a try, it would be better than drilling a hole in the front of engine if it worked.

Kmot

My Feedback: (24)

Dave, the Maltby I used was sourced by my employer. But I think it must be sold at places like Pep Boys or such as I have seen other people on the 'net make reference to using it. Since I don't get it for free anymore ( ) I will try some KW next time I need to buy a penetrant.

Motorboy: As for the screw extractors not being hard enough, well my experience has been that they do indeed take a bite into very hard material. In fact, the screw extractors I use are so hard that if you put a slight bend on them while turning out a bolt they will snap like a twig. I suppose it just depends on who the manufacturer is and possibly like bolts themselves they come in different hardness.

wcmorrison

My Feedback: (2)

Sorry, guys, I used an easy out and it worked. And yes, I believe easy outs are hardened. The taperedwooden dowel just did not get it. I am sure a drill slightly larger than the hole in the wrist pin will also work, but I did not have one. After fighting it for a day with wood, the easy out did it in seconds.

But then, I'd guess my wrist pin had not been but one season while the wrist pin in the .61 has been in there for years.

Anyway it is all back in there and working just fine.

Cheers,

Chip

DarZeelon

Quote:

ORIGINAL: Motorboy


Dar...
Read in early post #3 as here: Important!: Use a drill bit that is smaller than the span between the valve-lifter bores and larger in diameter than hole in the wrist-pin, so the end of the dril, or rod can drive the stuck wrist-pin out of piston..

Also not hole in the bore for the valve lifter, no leakage from crankcase or from valve lifter bore...

I understand, Jens and Jim.

Since I don't have an OS four-stroke engine, I did not know if the valve-lifter 'tower' is a solid structure, or a hollow one with the valve-lifter bores cast in.


Sure the sleeve will blank-out the new hole in the crankcase, but I did not know the sleeve is held all along its length in the crankcase...

The YS.61 sleeve, for example is relieved along ~30% of its length and is not touching the sleeve there.
If the sleeve and the bore in the crankcase are in full contact, there should not be a problem there either.

Motorboy

Yes.. correct.
The second problem are how much are angle in the tapered screw extractor, more angled extractor will not keep so well in the hole as a less angled extractor can do it better..

I want there was treaded hole inside the wristpin in all 4 stroke engines as a standard part in case the wristpin was stucked in piston and can pull out with screw or new tool for 4 stroke engine: wristpin puller.
The model engine engineer has overlooked the problem in future in case the engine need maintenance = Stucked wristpin!!![:@]
I can make new wristpin with treaded hole of hardened drill rod (silver steel) to all 4 stroke engines in my collections.

The valve lifter "tower" is a solid structure in all 4 stroke engines. The lifter are running in light alloy (crankcase).

DarZeelon

Jens,


Other four-stroke engines, which are not OS clones, will never encounter such a problem.

With a Saito, for example, the piston and con-rod will come out as a unit, after the cylinder is removed.

Removal of the wrist-pin for disassembly, with the piston in out the open, is a piece of cake.

Motorboy

Yes, precisely i am talking about same crankcase construction except Saito with 2 part crankcase/cylinder in this tema..

Flyboy Dave

My Feedback: (21)

You made a good remedy to a difficult problem, Jens. [sm=thumbup.gif]

You said you tried all the normal methods, and the pin would not budge. You had two choices:
1. put the engine down, and forget about repairing it.
2. improvise an expedient method of repair, even if it is unorthodox.

You had the plan to fix the engine with a method you figured would work. It did work. There
was no damage to any important part of the engine....and the holes you made in the engine
are easily repaired with out even much of a cosmetic blemish.....good work.

People that have not attained a journeyman level of proficiency in the mechanic field may
not know that "desperate times call for desperate measures". The ability to invent ways to
succeed in a difficult mechanic problem is what makes a mechanic a true mechanic, not
just a "parts changer". A lot of people can change out the parts....not everyone can invert
ways to succeed.

Like you said....this method was a last resort. Either find a way to succeed....or fail.

You succeeded....good on ya'. [sm=thumbup.gif][sm=thumbup.gif]

There were times at my fathers garage when a hole was drilled in the firewall of the body
so an expansion plug in the back of the head, or block could be removed. Sometimes you
have to remove a tire from a car and cut a hole on the wheel well so a spark plug could be
removed. These are things that are done to accomplish "impossible jobs". You know what I mean.

FBD.

FBD

Motorboy

Dave.. thanks..

As rule before i make encroachment at the engine, then i am thinking first[sm=confused.gif]:

1. Will it be possible to make change in the engine construction without weaking the engine?
2. Are there possible to come into the parts who are difficult to dismantle?
3. Are the engine parts available before i am removing the part with cutting tool to example the connecting rod are cutted of before the piston are removed from engine.
4. Are the engine parts possible to replaced with a new machined parts produced in home workshop?

My biggest handicap are damaged crankcase, camshaft with gear and crank shaft with gear, other parts no problem..

Kmot

My Feedback: (24)

That is why Dave is a member of the BFH Garage and has a really big hammer!

errie

I really dont think what Motorboy did was a bit drastic, I have a 40fs and allmost went through therapy. I just could not get that wristpin out [:@]

I decided to try one more time, I put the motor in the oven and heat up that OS ssssmokin hot. I took a screwdriver that fit tightly in the pin and start to push,pull side to side ( like what I did so many times before) The next thing I saw is the wristpin on the floor, I allmost carried on what I was doing, when I relized what happend. I was really glad I got the pin out!!!

Well, in previous attemps, I must have broken the ring and slightly marked the piston on the top side with a screwdriver. I inspected the piston and I can clearly see a mark [:@]

I just wonder if this is serious???

I see the bearings are shot, so I need to replace them. The rest of the motor looks in a fairly good condition I bought it of a friend for R200 (+/- $25)

w8ye

My Feedback: (16)

It should give satisfactory service for some time with a new Frank Bowman ring and new R/C Bearings

The notch on the top corner of the piston, while not good will not cause an immediate failure.

errie

Can anyone direct me to Frank Bowman's website or email

w8ye

My Feedback: (16)

Frank C Bowman
1211 N Allen Ave
Farmington, NM 87401-3568
505-327-0696
[email protected]

http://www.rc-bearings.com/

errie

Thanks w8ye

Does anyone know what can I use for a substitude to those teflon rubbing pads on the ends of a wristpin. I see tower sell the pin with those pads, and it looks like the only way to get them from tower.
This particular model 40fs uses brass ends (looks like it) I had to destroy the one side in order to get the pin out.

I dont want to operate the engine without those pads!!!

proptop

My Feedback: (8)

Looks like a Brass eyelet?
Servo eyelets are probably too big though?

submikester

My Feedback: (6)

When I Went through this, since you can't buy the little teflon ends separately (well, I couldn't find them) I was going to purchase the Magnum 91 RFS wrist pin which comes with 2 and is only like $5.00. It helps that I have two of the 91s.

I contacted Hobby People about buying just the wrist pins and they send me 3 wrist pins and only charged me like $1.50 for each. Great service from those magnum folks, no hesitation buying their engines...I used the teflon on the OS engines though...

Motorboy

errie..

Both OS FS-40 and OS FS-40 surpass has same piston, wristpin and cylinder, you can buy new ring and wristpin to your old OS FS-40.

The older wristpin had bronce pads (pads fastened to wristpin) while the newer wristpin has lose nylon pads.

errie

Thanks Guys

I will try to get hold of a new wristpin with those teflon caps!!!

PlaneKrazee

My Feedback: (14)

Motorboy,

Good work.

Horizon sells pads for thier engines, one size must fit close enough you get six in a pack.