stunthanger.com
Engine basics => Engine set up tips => Topic started by: KEITH McCRARY on August 31, 2018, 05:21:55 PM
-
Randy,
I have two new Magnum .36 xls engines. They have been on the shelf in their boxes wrapped in original plastic bag for over ten years. Yesterday I pulled them out and they will not turn over. I do not want to scar the piston or sleeve by forcing it. How should I proceed?
Keith
-
Randy,
I have two new Magnum .36 xls engines. They have been on the shelf in their boxes wrapped in original plastic bag for over ten years. Yesterday I pulled them out and they will not turn over. I do not want to scar the piston or sleeve by forcing it. How should I proceed?
Keith
Hi Keith
You can remove the back plate and glow plug, put in some PB Blaster oil, then heat the engine up after about an hour or 2 soaking, they should turn over free, look for corrosion first before you oil it up, also you may see hard dry oil on the rear bearing or around the crank counterweight, which may cover the bearing, try to spray oil behind the crank so the rear bearing gets oil. If anything goes wrong post again, you can clean any hard dry oil out with WD 40 or carb cleaning spray, the reinstall backplate and oil with after run oil
Randy
-
Randy's advice should get it loosened up, but it's probably not from rust or coagulated oil. I checked otherwise unopened Magnum 36s, and both where shipped with the piston at TDC. Heat alone should work. Once I got mine off of TDC and put a glow plug in it, everything was fine and the oil looked fine.
Brett
-
I may have a week's employment, just un-sticking my own stock of Magnum XLS .36's, a .46, and I think 3 .52's and at least a couple of XL .53's, .25's and .28's. They oil the dickens out of them at the factory...I wouldn't worry about rust. LL~ Steve
-
I have setup over 100s of these, and I have seen them as Brett described, set on TDC, I have also seen them with hard dried oil, and I have had them here on TDC with nearly zero oil in them, So I would still suggest looking into the backplate area, it easy to do, and will not hurt anything, The rear gasket is plastic and clear, and normally will not tear, at least I have not torn one yet
Randy
-
I have setup over 100s of these, and I have seen them as Brett described, set on TDC, I have also seen them with hard dried oil, and I have had them here on TDC with nearly zero oil in them,
I don't know what they were thinking on that one, even if it starts with oil in it, leave it at TDC for more than a fraction of a second, and the oil all gets displaced from the piston/liner interface, and it's not easily coming back apart. Two of mine (which I hadn't even unwrapped all the way until last night) were nearly exactly at the top. That had to have been on purpose, and without heat, it was going to take pounding on the prop to get it loose.
Brett
-
Thanks everyone. When I put them in the oven am I just warming them up at 150 degrees for an hour or two? Or do I full blast them at 550 for an hour or two?
-
I don't think I would bake them in the oven. Just open the back and remove glow plug as suggested, add oil, then use a covering heat gin or hair drier on the head. Get it really warm to the touch and then try wiggling the prop.
-
Thanks everyone. When I put them in the oven am I just warming them up at 150 degrees for an hour or two? Or do I full blast them at 550 for an hour or two?
DO NOT put them in the oven, heat the top of the case and head with a monocoat heat gun or hot hair dryer, you can do too much damage in the oven, and that is not needed, juts use the gun for 10 or 15 seconds
You want to get the outside of the head and case hot without getting the piston hot, so it does not take but 10 or so seconds
Randy
-
Piston was probably at TDC because the assembly crew was checking to be sure the piston didn't hit the head. It can happen, even at Fox, Veco and K&B. ;) Steve
-
Thanks.
-
We hope to hear back of your success!!!
-
Thanks everyone. When I put them in the oven am I just warming them up at 150 degrees for an hour or two? Or do I full blast them at 550 for an hour or two?
150 is safe enough, your car gets that hot on a summer day. 550 will certainly destroy something! But you probably just need a heat gun for less than a minute, as Randy says.
Brett
-
I think people are overthinking the engine stuck thing. Just stick a prop on it and pull it off tdc. Maybe pull off the backplate so you can oil the rear bearing . The only new motors that have passed through my hands that really need complete disassembly are fox motors that were run at the factory with castor oil and have been sitting around for a few years.
-
If you remove the backplate, you would be able to see if the piston is at TDC, or it maybe off slightly on way or the other, you would turn the prop that way if, it is on one side or the other at TDC
You can damage, the bearing seal, gaskets, or maybe other things at 550 degrees in an oven, is why I posted that, plus some other things that you do not want can happen, and "IF" you have dried oil, that can make it worse
When the glow plug out and the back plate off, it is very easy to see the inside, oil the engine, and clean anything out that you do not want in it, also the already mentioned rod check to see exactly where the piston is, and removing these parts is very easy and simple
The reason you want to heat a cold engine up quickly with a heat gun, is so the outside case/sleeve , gets hot and expands away from the piston, If you heat it slowly in an oven, it will heat the piston and the piston will grow to match the sleeve, ie.. not getting it loose, also when you pull it out of the oven, then sleeve/case starts cooling faster than the piston, and will actually get tighter on the piston.
Randy
-
And it seems plenty easy and logical to oil it up, and hit the head/cylinder with a heat gun or hair dryer....
Why anyone would not want to do that is beyond me.
-
I think people are overthinking the engine stuck thing. Just stick a prop on it and pull it off tdc. Maybe pull off the backplate so you can oil the rear bearing . The only new motors that have passed through my hands that really need complete disassembly are fox motors that were run at the factory with castor oil and have been sitting around for a few years.
With ABC/AAC engines, you sometimes have to absolutely hammer on the prop to force it loose, or put far more torque on it than you would want. It's not coagulated oil, it's cold-welding or something very like it. Heat it up, the cylinder expands, and you can move it. In the case of both of my engines, it felt completely locked, I heated it up a little, and it moved easily and was very free.
Brett
-
Not everyone has one - but engine fiddlers should - open up all the cavities (as much as possible and drop into an ultrasonic bath for 10 or 15 minutes - rinse out and repeat. Will free off most things and apply a good clean to others. I use mine extensively for Bike carbs - always describe the purchase to the 'little lady' as a Jewelry Cleaner (which it does as well !)