Engine Help Needed

[Carnold]

Hey Guys, I recently bought a 1956 Simplex Service Cycle Automatic and when I bought it the engine was completely torn apart... I honestly have no clue where to start. I want to rebuild the engine now that it’s apart, but I don’t really know what exactly I can do to it.

I’m thinking about having the block and head soda blasted. Is that a good idea? What else should I do? Replace the piston? Should I have it re-sleeved? Any help wold be deeply appreciative! Thanks!

BTW, how can you tell a 125cc for a 150cc engine?
-Connor

[pd]

New bearings , gaskets and seals . Replace all soft parts .
Measure piston to cylinder and crankshaft to case to determine clearances . That will determine if anything needs to be changed . 

125 cc motor bore is 2" .

Soda blast if you like , but insure any bearing/seal surfaces remain untouched .
Check all mating surfaces for true flat .

That should keep you busy for a couple minutes .

Pete .

[Ricks]

I glass bead all my engine cases, inside and out. As far as I’m concerned,there are no surfaces on a Simplex case that are bearing surfaces.  After blasting, I lightly sand and polish them so they look nice.

A word of caution, Do Not pound the bearings out cold! You will ruin the case.  Heat the engine to 400 degrees in the oven, or as I like to do, outside on the gas grill.  After 5 minutes or so, the aluminum will expand and the bearings will just about fall out.  Now, blast the case, clean it up.  When you are ready to install new bearings, put them in the freezer for 15 minutes, reheat the engine case to 400 and the bearings will drop right in with a little tap. 

Download a copy of the M manual, and it will show how the motor goes together.

As for piston and rings, I always use a new one from Wayne. You can send him your cylinder, and he will bore the cyclinder and fit an oversized piston for you, or if you have the equipment, you can do it yourself.  When rebuilding the motor, it is a good idea to get a new, billet connecting rod from Wayne, as the originals are known to fail, with catastrophic results.

Another word of caution, do not pry the flywheel off! The flywheel is removed by using the pinion gear to press against the loosened crankshaft nut.  Flywheels are delicate, and are hard to find!

[pd]

I glass bead all my engine cases, inside and out. As far as I’m concerned,there are no surfaces on a Simplex case that are bearing surfaces.  After blasting, I lightly sand and polish them so they look nice.

Sounds like you are making work . Blasting , then taking some back off .
Why not leave those surfaces factory smooth in the first place ?
And , it would seem to me that the crank seal would seal better on a smooth surface , but maybe I'm wrong ?
I guess it comes down to different strokes , so to speak .

Pete .

[Ricks]

I glass bead all my engine cases, inside and out. As far as I’m concerned,there are no surfaces on a Simplex case that are bearing surfaces.  After blasting, I lightly sand and polish them so they look nice.

Sounds like you are making work . Blasting , then taking some back off .
Why not leave those surfaces factory smooth in the first place ?
And , it would seem to me that the crank seal would seal better on a smooth surface , but maybe I'm wrong ?
I guess it comes down to different strokes , so to speak .

Pete .

Blasting gets rid of all the discoloration. 

The crank seal is all on the crank, not on the case. If you are worried about sealing on the case, you could put a little rtv on the outside of the seal, but I think that is totally unnecessary.  All my bikes start right up, so I must be doing something right.

[pd]

I glass bead all my engine cases, inside and out. As far as I’m concerned,there are no surfaces on a Simplex case that are bearing surfaces.  After blasting, I lightly sand and polish them so they look nice.

Sounds like you are making work . Blasting , then taking some back off .
Why not leave those surfaces factory smooth in the first place ?
And , it would seem to me that the crank seal would seal better on a smooth surface , but maybe I'm wrong ?
I guess it comes down to different strokes , so to speak .

Pete .

Blasting gets rid of all the discoloration. 

The crank seal is all on the crank, not on the case. If you are worried about sealing on the case, you could put a little rtv on the outside of the seal, but I think that is totally unnecessary.  All my bikes start right up, so I must be doing something right.

 You're just real lucky . LOL

I thought the seal was there to seal the crank and the case from leaking . If the seal is only tight around the crank , what's to stop 'pressure' from escaping around the outside edges ?

Pete .

[Ricks]

It does seal around the outside of the case.  The lip on the crank is about .005 or so wide and is sealing on a rotating assembly  whereas the case seal is .200 wide and a fixed seal.  I don’t see an issue. 
BTW, I have used both single and double lip seals, both without issue.  I prefer to use the double lip, but i couldn’t find one the right width, so went with the single lip.

[pd]

I tried both single and double lip , but , I wasn't sure that the standard 30 mm seal was doing a go enough job of sealing against the bushing . I bought and installed a 29 mm seal , which seems to be doing a much better job .

Simplex chose to run a seal bushing . Probably because of the wear factor . Cheaper to replace a bushing than a crankshaft .
 At the same time I last replaced the crank seal , I wrapped a couple rounds of gas rated thread tape around the crank where the bushing normally butts against it . That , to eliminate any possible leakage from that point .
It should be noted that I'm still running the OEM seal bushing . I saw that it did have a wear ring where the original seal rode , so I flipped it for a better seal contact surface .
 
And , like I said , just different strokes that obviously work .

Pete .

[Ricks]

Pete, why didn’t you just get a new bushing?  Seems to me that would have been the proper fix. 

[pd]

The bushing flip side seemed in unused condition , so , I used it .
Even on the flip side , the 30mm seal wasn't totally impressive . Sure , it fit and it even seemed to have a bit of lip pressure , but not as good as the 29mm .

A short story :

I'm sure of the quality of the sealing , as the 29mm seal held a much higher amount of pressure than I intended or it will ever have to while the motor is running . During a leak down test , I applied air via a compressor ( in short spurts ) instead of a bicycle pump . The last spurt put the pressure way up there . Made me draw and hold a deep breath while I released some air , which took a lot longer than I wanted it to ( no release button , just a tire rim stem ).
Anyway , if that seal was gonna blow , it would have right there .
That little fiasco did push the seal out a hair from where I had it seated , but it didn't blow . 

Pete .

[Ricks]

The bushing flip side seemed in unused condition , so , I used it .
Even on the flip side , the 30mm seal wasn't totally impressive . Sure , it fit and it even seemed to have a bit of lip pressure , but not as good as the 29mm .

A short story :

I'm sure of the quality of the sealing , as the 29mm seal held a much higher amount of pressure than I intended or it will ever have to while the motor is running . During a leak down test , I applied air via a compressor ( in short spurts ) instead of a bicycle pump . The last spurt put the pressure way up there . Made me draw and hold a deep breath while I released some air , which took a lot longer than I wanted it to ( no release button , just a tire rim stem ).
Anyway , if that seal was gonna blow , it would have right there .
That little fiasco did push the seal out a hair from where I had it seated , but it didn't blow . 

Pete .

Next time I need a bushing, I think I will make it 30.5mm and see what happens.

[pd]

Rick ,
I'm sure the extra .5mm would insure a better seal . Specially , if a double lipped seal would be used .

I noticed , even with the OEM seal and bushing , that the seal lip rested right at the edge of the bushing .

Do you see any problem with making the bushing a bit longer or shimming it out ? Not enough to interfere with the stator mounting .
That should afford a better sealing surface .

Seems the difference could be 'corrected' by shimming the transmission .

Pete .

[Ricks]

Rick ,
I'm sure the extra .5mm would insure a better seal . Specially , if a double lipped seal would be used .

I noticed , even with the OEM seal and bushing , that the seal lip rested right at the edge of the bushing .

Do you see any problem with making the bushing a bit longer or shimming it out ? Not enough to interfere with the stator mounting .
That should afford a better sealing surface .

Seems the difference could be 'corrected' by shimming the transmission .

Pete .

Pete, what width seal do you use?  I like the 6mm double lip seals, but I have not been able to find them again.  I think Wayne sent me an 8mm seal one time and I thought it was too wide, it wanted to bind up against the motor pulley.  I bought a 5mm single lip seal locally and it worked fine.

[pd]

Hmm , never really thought about something narrower .
I'll have to look into that .

I tried a 7mm double lip , but , the outer seal lip hung over the edge of the bushing .
Currently it's a double lip 6mm x 29mm x ???mm ( Don't recall the outside measure) seal doing the job .

I had a time finding that seal . Ordered it out of Texas . And , you think I can find the paper work on that ?
Still looking .

Pete .

[pd]

Rick ,

I found the paper work on the 29mm seal I have in my motor .

I must be getting old . My memory wasn't exactly right .
The seal is a 7mm width .
Here's a link to that seal :

https://www.avxseals.com/Shaft-Oil-Seals-TC29x52x7-p/TC29x52x7.htm?gclid=CjwKCAjwg_fZBRAoEiwAppvp-eIjExQQM8bozGRG6dbGpL181Ib5Asns3qakzaDb3nUlFm4vSehyEBoCETwQAvD_BwE

Sorry for the misinformation .

Pete .