Sc 52 fs

[Adsjking]

Ok so I've opened up my sc 52 fs that I recently acquired. I do not know the previous history of this engine but someone has been inside as there is a scratch on the conrod and I haven't run it yet.

 

It's a bit grubby on the outside but internally I think it looks ok?

I'd like to at least start with a clean engine for the new model it's going in.

 

Would you strip and replace bearings (I've already ordered new ones)

And completely clean the engine?

 

Or just clean up the outside? 

 

 

[Mark Hewett]

No rust on the crankshaft web, and the top of the piston being so clean but with scrub marks, makes me think this engine has had little or no running after a re-build.

 

If that rear bearing isn't rusty - it doesn't look it in the photo, and the engine turns over smoothly and freely, I would just give it some oil and run it as it is.

 

[Adsjking]

The crankshaft web has some pitting from previous rust but no rust now inside or on rear bearing.  I was shocked to find the top of the piston so clean but with scruff marks, it's obviously been scrubbed.

 

How would I go about cleaning the outside, without stripping it down?

[Jon H]

it looks good. i would be inclined to put it back together and fire it up provided the bearings feel smooth. For cleaning i dont bother with oil staining and only remove loose dirt as this risks being ingested by the engine. 

[Adsjking]

Yes bearings feel smooth.  If you were to clean it though, how should I do it? I've read up a bit on it and seems to be such conflicting advice on the topic.

[Cuban8]

Unless you strip it right down and give it a thorough clean in an ultrasonic bath as one does with motorbike carbs etc, then you're stuck with a manual method that depending on the intensity and type of staining, gives variable results in my experience.

Your motor looks pretty good both mechanically and cosmetically, so I'd be inclined to run it as is and see how it goes. If you do want to give it a brush up externally, I've had good  results using domestic paint stripper gel - the stuff that smells of ammonia - only a small amount needed, and gentle cleaning with a toothbrush (the wife's, not your own😄). Wipe off with several damp cloths, usually takes a couple of applications. Don't rinse freely, as water will be bound to get inside. At least its not caked on Castor which even paint stripper has trouble with.

A friend used to boil his engine casings in a strong biological washing powder solution to get rid of Castor stains - rather like a good soup - bring to the boil and then simmer until done .......yummy 😝.

I've used the paint stripper  method loads of times with no detrimental effects to any engine (my ancient Magnum 91 had an overnight soak when I stripped it down for a refurb some years ago) but do satisfy yourself by trying it out on small section first.

[Mark Hewett]

1 hour ago, Adsjking said:

Yes bearings feel smooth.  If you were to clean it though, how should I do it? I've read up a bit on it and seems to be such conflicting advice on the topic.

It's likely that someone already cleaned it as best they could and re-built it - and what remains is stubborn burnt on castor. If that's the case I'd be inclined to just leave it. You're putting it in a WW1 style model right? You could just regard a bit of burnt on castor as 'authentic period patina'.

[Adsjking]

Yes mark an elder 40.  It's my ocd kicking in, I'm a bit particular like that. It doesn't sit well with me putting a dirty engine in a brand new model.  I have some screwfix no nonsense paint stripper which is a gel i could try. I'm happy to strip and rebuild if easier and I have an ultrasonic cleaner but apprehensive to use it as I'm worried about discolouring the aluminium.

[Mark Hewett]

26 minutes ago, Adsjking said:

Yes mark an elder 40.  It's my ocd kicking in, I'm a bit particular like that. It doesn't sit well with me putting a dirty engine in a brand new model.  I have some screwfix no nonsense paint stripper which is a gel i could try. I'm happy to strip and rebuild if easier and I have an ultrasonic cleaner but apprehensive to use it as I'm worried about discolouring the aluminium.

The product I add to water in my ultrasonic cleaner is marketed as a carb and engine parts cleaner. It doesn't seem to discolour aluminium castings on a normal run of say 30 minutes - but has somewhat discoloured one after 2 hours or so - trying to soften/remove burnt on castor. It may have been that the fluid was contaminated by the steel parts, and fresh fluid with only ali parts in would have been ok for long periods - I dunno. 

 

I guess there is some acid in the fluid, as steel parts want to rust over very quickly after cleaning. Once they're out, rinsed of and dried with heat, oiling them straight away seems to prevent that.

 

Mechanical cleaning of burnt on castor on ali casings, with fine steel wool or a brass wire brush, itself damages the cast finish. How far do you go?

 

I haven't tried paint stripper or biological washing powder - maybe that works better?

 

[Cuban8]

1 hour ago, Adsjking said:

Yes mark an elder 40.  It's my ocd kicking in, I'm a bit particular like that. It doesn't sit well with me putting a dirty engine in a brand new model.  I have some screwfix no nonsense paint stripper which is a gel i could try. I'm happy to strip and rebuild if easier and I have an ultrasonic cleaner but apprehensive to use it as I'm worried about discolouring the aluminium.

Give it a try. Paint the goo on where needed and then put the motor in a plastic bag to soak for about an hour - the stripper tends to lose its effectiveness otherwise, as the ammonia in it evaporates quite quickly if left to the open air. I reckon a couple of goes will see a marked improvement with plenty of toothbrush brush agitation to loosen things up.

I do get your OCD - a nice new model and grubby engine don't sit too well with me either. My engines stay so much cleaner since running fully synthetic fuel, even the old stuff with a couple of percent Castor would make a mess, particularly on fourstroke exhausts and look 'orrible in no time .

Re the Ultrasonic cleaner - probably depends on the type of cleaning fluid used - some are a bit caustic and will remove plating if overdone. I've only ever used fluid intended for carburettor cleaning on carbs but I understand that a degreaser like 'Elbow Grease' which is more benign can be used.

I guess some experimentation is needed.

Edited April 20 by Cuban8

[Adsjking]

@Cuban8 I plan on using the 5% optifuel you suggested as well so ideally would like to start with a clean engine.  

There's an ultrasonic carb cleaner on Ebay but seems pricey at 19.99 for 1 litre.  There's one on eBay for 11.99 which says its safe for aluminium but don't leave in solution with other metals as it can darken the aluminium.  Might get it n try it on my tt 46 pro first and that engine looks pretty rough and just do the aluminium parts seperate.  

[Adsjking]

Anyone know where the best place is for spares for these sc 52 fs engines? I've stripped mine down ready for the ultrasonic cleaner and have discovered who ever has been in there before me has lost the thin aluminium washer that sit underneath the head. Also could do with some new push rod tube o rings.

 

Also shouls there be a cap here? The hole is open straight onto the piston sleeve.

 

Thanks again for all the help.

Adam

[Glenn Philbrick]

I've stripped a few of these engine's and not found any with a head gasket. The hole in the case is to allow you to replace the gudgeon pin and is covered by the liner when in position.?

[Engine Doctor]

I would probably use as is as it doesnt look to bad , obviously having been stripped before.

A decent degreaser mix works well in ultra sonic cleaners. Tesco kitchen or Mr Muscle degreaser suitably diluted work ok but check on ali first.

Tip. To avoid using excessive amounts of cleaner or solvents in US cleaners. Find a glass container , jam jar etc with a screw on lid that your parts will fit into plade parts in jar and fover with chosen cleaner and screw on lid. Now place in US tank and fill tank to the level line with water. Often warm water will speed up cleaning.

Using a sealed jar also allows the use of solvents  that should never be used in the nain tank due to fire risk. Even so only ever use solvent in a jar in a safe , preferably outdoor place. I frequently used cellulose thinners as a cleaning agent for cleaning screws and small bits but always in a sealed jar.

To restore scruffy engines to a " as new look" the castings need to be bead or vapour blasted. I use very fine glass beads for an excellent finish then a good clean in the US to get any beads out . But thats just my engine OCD kicking in.

Occasionally you will  find a shim in the head . These are often well stuck in and look like the face of the cyl head, but often found in the bottom of US tank after a clean,always worth a check as if left out you could have an engine that bite and throws props.

 

No cap fitted in gudgeon pin fitting hole.

 

If your going to all the trouble of a full strip and clean then its an ideal oppertunity of fitting a new set if bearing, dont forget the camshaft bearings.

Good luck and keep engines alive

 

[Adsjking]

I bought carbusonic cleaner as didn't want to start experimenting yet and it cleaned up my tt 46 pro lovely. Two twenty minute cycles at 40-50c and it didnt darker the aluminium at all. I did the aluminium parts separately.  

Bearings look spotless and feel smooth but I'll replace them with the skf ones, I've bought them now so may as well use them.  I'm just about to put the cleaner on now so will check for the shim after cleaning.

 

Thanks again 

[Adsjking]

Definitely no shims after cleaning, and to top it off I've lost one of the circlip that holds the valve spring in plane.  Ive had a Google but cant find any spares.  Anyone know where I can get these parts please? I'm not having a good day.

Edited April 23 by Adsjking

[Engine Doctor]

Go over the floor or carpet with a strong magnet .whatever you dont let the vacuum loose ; or try shining a torch along the surface and it will make any small parts visible  . Perkins should be able to supply a new one as SC  engines are back in production.

When removing them or fitting them put the head in a large plastic bag . 

Edited April 23 by Engine Doctor

[Paul De Tourtoulon]

20 minutes ago, Engine Doctor said:

Go over the floor or carpet with a strong magnet

I took the motor out of my new lathe and lost 2 bolts, I got my torch out only to find them stuck on the torches' magnet,,,

[Rich Griff]

So you lost a split collet ?

 

As ed says, use a torch placed on the ground, and turn the torch so the light beam shines on the surface, similar to a light house. 

 

Look down/along the beam.

 

When small things are dropped, sometimes they can end up stuck in your clothes, shoes, down the nearest hole or well away from where you were working.

 

Did it spring off just missing your eye, or did you hear it tinkle down bouncing off stuff ?

 

Did you hear it land ?

 

Hope you find it !

 

It will always be in/at the last place you look/ed.

Edited April 23 by Rich Griff

[Adsjking]

I found it, i can't believe it. I thought it had gone in the US cleaner and i poured it down the sink even though i cupped the water out checking each time for bits. I thought i had been so careful. Turns out it never made it into the cleaner 🤣. Ive emailed perkings to see if they have the shims and orings for push rod tubes. 

Looks like should be two shims

I also don't have part 52208, that was the cap I was referring to that covers the hole to the gudgeon pin. Mine gets covered by the piston sleeve. Newer/older models?

 

 

[Adsjking]

What oil should I use to rebuild as well please? I have the following

3in1

Sae30

2stroke oil

Atf

 

Also best place to get 5%nitro fuel model tecnics or optifuel 

 

Thanks for all your help, i hope this engine bloody works now.

[Nigel Dell]

52208 looks like the ptfe pad that goes in the end of the gudgeon pin to me and not on the crankcase.

[Rich Griff]

Glad you found the missing split collet, althought the exploded view is not that clear showing one collet per valve ?

 

As a matter of interest....

Could you post a picture of the method of valve spring retention method please.

 

Does the collet have a *double diameter hole* with the cap having a single diameter hole with recess for collet ....so all the "fits" effectively lock the spring, cap and collet to the valve stem ?

 

The collet fits over the stem top, slides over, then is held in place by cap, valve stem and spring.

 

This method is used in some ohv car engines etc., etc., etc...

( Triumph ?? )...

 

52088 only one shown...is there a picture or description, even dimensions of this part please ?

 

No ports in cylinder sleeve on this engine ( 4 stroke ) but gudgeon pin float is usually controlled ??

 

Assembly lube, fuel, after run oil, some would use atf, others would use air tool oil....

 

Assemble and run engine sane day ?

 

What oil mixes with the fuel you intend to use ?

 

 

[Rich Griff]

Ditto Niel...

[Engine Doctor]

assemble with Air tool oil for storage or if you going to use it soon then Two stroke will be fine Dont use 3 in1 its only ant good for door hinges and sets like varnish and Sae 30 is too heavy .

 The diagram shows two shims for use with different fuels  . Two shims will make engine a little easier to tune with less risk of prop throwing .

The PTFE plug that goes in the end of the gudgeon pin is vital to stop the gudgeon pin from scoring  the cylinder wall.