Running in a steam engine

[Brian Rupnow]

I find that the more engines I build, the less they need to be run in. No doubt this is a testament to the fact that my machining abilities are improving with experience. One of my favourite engines, my twin horizontal which was built early on in my machining life was so stiff that I broke a silver soldered joint in the crankshaft while attempting to "run it in" with an electric drill. I don't personally see anything wrong with "running in" an engine with an electric drill, so long as the engine is free enough that it can be turned over by a hand on the flywheel, and everything is kept liberally coated with oil during the "running in". Speeds should be kept low, and the running in shouldn't take more than half an hour. ----Brian

 

[lensman57]

I seem to remember the original VW beetle was run in on a light oil for the first couple hundred miles then the oil was changed out for the normal weight stuff.
Tin

Hi Tin,

I remember many decades ago while I was livung in Iran, the normal running in practice for a new engine was exactly as you mentioned. light oil for the first 600 KM, rpm between 1200 and 2000 and no undue load on the engine, then the car was taken to the garage and the oil drained and valevs adjusted and so on. That is how my mum ran in her first car engine, my dad wouldn't drive, an iranian built Hilman Hunter and it lasted for 8 years.

Regards,

A.G

 

[Tin Falcon]

My Mum got one of the first vw bugs in the area in IIRC about 1963 . I was still a toddler at that time . so The memory of the run in procedure is a little vague.
Tin

 

[rkepler]

The only running in that I've done on engines was in the bearings - they don't always come out perfectly in line and can tighten up a bit when the caps are tightened. In those cases I mix a little Timesavers lapping compound with light oil and put it in the bearing and run the engine with the caps loose, replenishing the oil/compound mix as I tighten up the caps. It usually doesn't take too long to get everything turning smoothly.

The nice thing about this method is that the Timesavers compound starts to break down as soon as it's mixed with oil, so it can be easily flushed without a complete strip and clean.

After the main bearings are run in (most of the time no lapping is needed) I run the engine on air with a light spindle oil, usually letting it run in the shop while I'm working. A couple of hours running usually makes things nice-n-smooth, an engine that wants 10psi at the start can end up running the same speed with 5psi after a couple of hours.

One source of "tightness" I've seen is when someone cranks down on an o-ring seal. They don't need much if any pressure to seal, loosen them up until they leak a little bit and see if things run. If so, let it run in a bit before tightening them back up, it'll loosen things nicely.

 

[Sshire]

I wasn't aware of Timesavers but it looks like it could be useful.
There is a "sample" kit which looks to be enough for a lot of the small engine lapping.

Tech info here

http://www.newmantools.com/lapping/time.htm

Best
Stan

 

[Sshire]

Wow! I just checked the prices. Rof}

http://www.newmantools.com/price.htm#TIME

Best
Stan

 

[Mosey]

Me too, now what else is there?

 

[Sshire]

I love the idea of the lapping compound getting finer and finally not cutting and easily removable.
Is there anything else like this?
Best
Stan

 

[steamer]

My 2 pence....if the abrasive is not "friable" like timesavers....I wouldn't do it!

You would be better off scraping in the bearing with a toolmakers reamer or a scraper, than risking it.....

....My 2 pence


Dave

 

[rkepler]

If you look here: http://www.ws2coating.com/index.html Here you can find the yellow and green kits separately for $30, so figure about $70-$75 for both and shipping. Someone sent me a link in the last few months for a full kit at the $70 price but I can't find it (gotta thank the KDE folks for screwing up a nice mail system).

(Poked around a little more - if you're getting both sets the McMaster price of $73 might be better).

 

[Sshire]

Thanks for the info. Since I'd mostly use it for aluminum and brass, the 1/2 yellow kit should be a good starting point. A lot better than the first prices.

Thanks again
Stan

 

[Florian]

Stan, you can get a set of diamond lapping paste for about 40$ (25.65 £).
I did order some of this compound from rdg tools; works quite well (I use it for honing)

You can also get them seperate if you only want some grit sizes.


Cheers Florian

 

[steamer]

Again, be careful with the abrasives that are not friable ( that don't break down)....I piece of grit left in there and it will tear it self up.....

Dave

 

[rkepler]

Stan, you can get a set of diamond lapping paste for about 40$ (25.65 £).
I did order some of this compound from rdg tools; works quite well (I use it for honing)

You can also get them seperate if you only want some grit sizes.

I only use diamond in an embedded lap and don't know another way. In the past I've embedded diamond in a Flex-o-lap when I had several holes to be lapped to the same dimension, using several of the brass ends to go from heavy action to light lapping action. The problem is that you can't change from a coarse lapping compound to a fine unless you turn off the surface and clean meticulously, I expect that even then you're likely to get some of the coarser grit into the fine lap and scratch the new surface. That's the nice thing with the Timesaver lapping compound, you can clean off the coarse and go to the next finer grit with no real concerns. That way you can use one lap for all the grades. The downside is that the lap gets eaten up some and won't do as many holes as it wears past adjustment.

 

[steamer]

I only use diamond in an embedded lap and don't know another way. In the past I've embedded diamond in a Flex-o-lap when I had several holes to be lapped to the same dimension, using several of the brass ends to go from heavy action to light lapping action. The problem is that you can't change from a coarse lapping compound to a fine unless you turn off the surface and clean meticulously, I expect that even then you're likely to get some of the coarser grit into the fine lap and scratch the new surface. That's the nice thing with the Timesaver lapping compound, you can clean off the coarse and go to the next finer grit with no real concerns. That way you can use one lap for all the grades. The downside is that the lap gets eaten up some and won't do as many holes as it wears past adjustment.

Agreed, the diamond is imbeded in the lap. Perfect! If you put it in the bearing with the shaft, the bearing becomes the lap ( the diamond embeds into it) and the shaft takes a beating.......which is why I suggested scraping instead of abrasive....

Dave

 

[Florian]

As I said, I only use diamond compound for honing...!

But you're right with the fact that diamond grits will stick in the softer material.
When I finished honing with one grit, I always clean the mandrel and then make some turns without any compound, just oil until the oil does not turn black immediately. That tells you when the abrasion is almost zero and therefore there are no diamonds anymore in the mandrel.

And it seems to work as I usually use 3 grades and I have never found any scratches from the coarser grits...

Whatever; the point is that diamond compound will stick to the softer material and therefore is NOT suitable for running in bearings!

Regards Florian

 

[steamer]

Oh and to be very clear....as the written word doesn't show facial expression or inflection, I'm not upset or emotional about my statement.....just sayin. ;D

MYO....I don't like abrasives in engines....I just think you can never ever really get it all out.



Dave

 

[Blogwitch]

I am a little like yourself Dave, but I have used my own diamond mixture on very hard steel cylinders that normal grit won't touch very well.

Normally, I only use oxide grit as the first cutting agent as it breaks down into smaller and smaller pieces as it gets used, eventually becoming almost inert in it's operation, and very easily cleaned out.

I usually finish off afterwards with jewelers rouge if I want a truly polished bore.

BTW, I have just treated myself to a set of castings to make a pair external hones. I don't know how they will work out, but I should be able to show the results in the not too distant future.


John

 

[steamer]

Agreed Bogs...but 1 differrence...I suspect you finished the cylinder with a dedicated lap, and you didn't use the piston as the lap......That's the bit that goes against my grain.....just sayin.

Dave

 

[Ryker Carruthers]

If you are building an engine like a 1/2 scale or 1/4 scale traction engine you should be worried if it isnt tight the first 6 or so runs, it may be real easy to turn over by hand but that just means when all the bearings get seated and wore in a little it will pound and knock like no other. when our 1/2 scale was finished 30 years ago dad said the gears would grind really bad so he started to mix valve grinding compound with the grease for the gears. 29 years later I see no scratches on the surfaces and the gears honestly look brand new. If the cylinder you use is cast iron and you cant get the finish super smoothe just run in with cast iron rings and you would be suprised how smoothe the bore is then and your rings will be conforemed exactly to the bore
2 cent
Ryker Carruthers