Toshi 975 said:

Hope you can find the right fuel pump push rod otherwise you are short of a squirt of gas ?
Probably some syndrome I have but I always arrange those push rod tubes in the way you have for the symmetry and always keep twisting them as you torque down the head to ensure that the seals seem happily seated and no pinching. So the question is was the engine originally designed to allow a small amount of oil to flow through those small cut outs from oil puddling in the depressions to lube the cam followers with the bulk of the oil flow going down the deeper central cavity where the oil feed pipe runs up to the rockers.
How wonderful it would be if the original designers of the 500 were available to answer questions about their designs.

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...exactly what I did with the seals but accidentally in my case, rather than a search for perfection or mechanical awareness, because it only occurred to me halfway through tightening to swivel the tubes into alignment.

I hadn't checked out the fit of that spacer on the rod yet. The rod is the one that came with the engine so I guess someone's been here before. This engine had definitely been used on a Fiat 500 before I bought it because the gearbox already had the correct driveshafts. I could rob the correct rod off another spare engine but to get it going I think I'll use the thin spacer.

I'm assuming that there is a surplus of oil-flow to the head which means that, (on level ground), the four shallow depressions abutting the tops of the tubes will be permanently flooded and overflowing oil down them. When you look closely at the casting, each depression is bounded by a slightly raised barrier on all sides. Going steeply uphill or downhill might have temporarily slightly deprived either of the two exhaust cams of oil when, as you say, the bulk of the oil would run to the central drain.

Toshi 975 said:

Hope you can find the right fuel pump push rod otherwise you are short of a squirt of gas ?

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I've discovered why the fuel-pump pushrod is too short for the correct and thicker spacer; it came like that as seen here three and a half years ago when I bought the engine.:bang: It was running well.

I think I'll change the rod for a longer one and get it to correct spec.

MAL_5777 by Peter Thompson, on Flickr

Looking good and great to see that through this current time you've got round to building it up. Unfortunately for me my Fiat lumps and gearbox's are untouched and sat behind my recently acquired 'Swedish Slipper' that is also not getting any love...…..


So my take on the valve seals is that they do indeed sit on the valve stems just above the valve guide and do indeed get pushed up to the height that the valve opens and remains there. My understanding of this methodology is the amount of valve under it picks up enough oil to lubricate the valve in the guide but the ring acts as a 'drip' to stop any excess that runs down the valve and potentially over lubricating the valve/guide and causing the engine to burn oil.... The note about using the same seals as a mini engine (or pretty much any A series engine)......I do believe they were just rings but I've got a feeling you could get an aftermarket seal which pushed onto the valve guide and the seal obviously had a hole in it for the valve to come through with a little spring around it causing a seal around the valve. This works well but then blows the valve lubrication out of the window.


On the VW aircooled engines it is a plastic type sleeve that goes on the valve and from memory is more 'free moving' on the valve but don't forget these engines are boxer engines and not vertical….


Anyway good look with the build and stay safe everyone...

The Whitakers said:

Looking good and great to see that through this current time you've got round to building it up. Unfortunately for me my Fiat lumps and gearbox's are untouched and sat behind my recently acquired 'Swedish Slipper' that is also not getting any love...…..

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Thanks; and there's lot more Fiat-related things that are receiving my attention...lockdown suits me fine. that's not saying I hope for the best for others who aren't so fortunate.

On the valve-seals, your way of fitting them echos Tom's (to which he added no explanation of the mechanical function of the seal so fitted) and so I won't repeat my own counter-explanation. But a couple of images might help illustrate my case. The first is of an exhaust valve from a 594 engine; they're specialised with the extra grooves for the collets which consequently have a different design. there is no space for a seal there but no seal should be fitted to the exhaust in any case. The second and third images are of an inlet valve. You can see that the collet sits high on the groove which begs the question to me, "Why is the groove so long?" The fact that the "O"-ring fits so well there and is not stretched as tightly as it would be on the main stem may not be the answer to that question, but it may be a part of the answer.

I add a quote taken from the page to which I have linked. Although the Internet is full of lies, whilst I can find pages which support what I'm saying. I can't find any which directly suggest the alternative way. Admittedly, this is not about Fiat engines...far from it!

As said before, it probably makes no difference either way.

"Cylinder heads can have one of three basic types of valve seals:

1. Umbrella-style valve stem seals fit tightly around the top of the valve stems and ride up and down with the valves Figure 12-17. The umbrella is a larger diameter than the valve guide, so oil drips off the umbrella outside of the guide. Umbrella-type seals are generally found on older (1980s and earlier) American-built V8 engines. They are not typically found in modern engines.
2, O-ring valve stem seals fit on top of the valve in a groove just below the valve spring keepers Figure 12-18. The O-ring seals the oil from leaking between the valve stem and the valve retainer. These seals were used primarily on General Motors V8 engines from the 1980s and earlier. O-ring seals are not typically found in modern engines.
3. Positive valve stem seals are used in today’s engines Figure 12-19. The positive seal fits tightly on the valve guide as the valve stem moves up and down inside of the seal. This type of seal is the most effective because it forms a positive seal between the guide and the valve stem. Positive valve stem seals have a small groove cut into the top of the seal that rides on the stem. This design keeps a small amount of oil against the valve stem and only allows a very small film of oil past it to lubricate the valve guide".

http://prod.lv2014.gener8cms.net/index.php/38-disc-brakes/section-2/cyheco/2826-valve-stem-seals

On '3-ring' valves, you should be using '3-ring' collets Peter---they are available

the hobbler said:

On '3-ring' valves, you should be using '3-ring' collets Peter---they are available

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....which is why I used them......

fiat500 said:

they're specialised with the extra grooves for the collets which consequently have a different design.

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I dug out the flywheel and gave it (by my standards ) a good clean.I had put a paint mark on to indicate the top when I removed it. After a scrub I can see a little dimple which I assume is the TDC mark. Doubt set in a little because slightly clockwise from this mark is a raised casting mark which is probably a flaw but seems odd to be the only one on the perimeter; but the flywheel can't be put on in any way to align with this in any case.

Looking closely at the crankshaft and near to where the counterweight has been drilled whilst balancing the crank there is an interesting inscription "-0,127". I wonder is this a statement of weight which needed to be removed or some other machining instruction?

Whilst there I have photographed one of the clever features I have commented about previously. It is one of the angled holes drilled from the inner groove of the recessed area of the face side of the flywheel. These cleverly allow any oil which might escape via the input shaft seal of the gearbox to make an exit to the back of the flywheel where it will be flung away from the "danger" area.

Considering how much time I theoretically have at my disposal just now, the engine build has slowed from a snail's pace to the speed of a Fiat 500 driving uphill with four passengers and a 479cc engine.

But I'm getting time to think....like, how is that six hole washer supposed to ensure the flywheel setscrews don't come loose. My guess is that it's not meant to, but that it's just to combine the force of the screws and clamp the flywheel evenly. Just as a precaution I used Loctite on the screw threads.

The oil pickup tube; the thick rubber washer which seals it to the crankcase is obviously a separate item which doesn't appear in a gasket kit. The spacer which goes between the pickup flange and the case prevents the washer from being over-compressed but how thick is it when new? I've only ever re-used one, using a sparing smear of my favourite gasket sealant and not seemed to have a problem but I'm sure it should really be replaced.

I've done an experiment with the standard sump. The thick gasket settles with time and you can carefully retighten it as often as you like but as the setscrews are never at full torque you always get a recurring slight leak. On the modern 500, sealant is the factory method for securing the sump, I (I know becasue I've just re-done one and it works really well), so I've done the same with this engine and will report back if it leaks. Doing it this way means the setcrews are fully tightened first time so won't back off as the gasket compresses.

Being that it made of steel, I cannot see any sensible reason as to why you should ever have to replace the oil-pickup spacer--but the rubber seal, yes.
I have an aluminium 3-1/2 litre sump on my 650 engine, and have tried the "silicon sealer and no gasket" method---so far it has been very succesfull. As you have mentioned Peter, with a gasket, even the 'rubberoid' type, the bolts are never totally tight, by using the sealer, the bolts can be fully tightened.

the hobbler said:

Being that it made of steel, I cannot see any sensible reason as to why you should ever have to replace the oil-pickup spacer--but the rubber seal, yes.

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Thank-you for the reply. I'm not sure if you're being pedantic about my misuse of grammar, but I hope I don't come across as so stupid as to think it was the solid steel spacer which might need replacement.

I've regularly seen it said that sealant can be useful with the aluminium sump, but not heard it mentioned with the standard pressed steel sump before now.

Apologies Peter--reading throuh your comments 1st time round I thought that you were talking about replacing the spacer, but, after your next comments and me re-reading it, I realise that you were talking about the SEAL which you had only replaced once---stupid boy! (me)

SWMBO has been very patient with me but I've had to move the engine to the garage. I modified my engine removal frame by fitting three legs which allow me to use it as a stand whilst I bolt on the last few components.

So now it only needs connecting to the fuel and electrical supply in order to get it started. I found that the exhaust which was supplied with the engine is quite new and had been modified by accurate use of a gas torch so that it fits perfectly using the standard Fiat 500 brackets.

In order to get the starter to be spaced properly I've fitted a gearbox bellhousing temporarily. The engine is very tight...not in a bad way, but I wanted to get the oil on the move before trying to start it. I had the brainwave of wrapping some polypropylene cord around the pulley and rotating the engine quickly . This seems to have worked as it brought oil right up to the rockers.

I might need to get some more petrol pipe first but should have the engine going over the next few days.

With rebuilt engines I have tended to turn the engine over with the plugs out using the starter motor befor attempting first start up

Toshi 975 said:

With rebuilt engines I have tended to turn the engine over with the plugs out using the starter motor befor attempting first start up

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Thanks Dave, I'll be doing that anyway. But I'm always keen to experiment and proved to myself that the pump is capable of self-priming, even at relatively low speed.

The Dynolite 20W50 running-in oil finally arrived so I was able to spark up the engine. The test took place with the engine sitting on my removal frame which now has tripod legs. So the few clanks in the video, (if you watch it) are the sound of the flywheel just catching on it. I am moving things about in the garage so you'll see the clutter of Sheila's shed where I had moved to. It really did start for the first time exactly as shown and there had been no exploratory firings before that.

I temporarily fitted a completely as-found starter-motor which came with another engine. I used the fuel-pump, thin spacer and short actuating-rod as fitted when I bought this engine. The slightly long HT-leads have been lying about here for ages. It has the standard points distributor and has a "modified" exhaust. Someone appears to have cut and welded together the pipes very accurately in order to be able to use the earlier type of exhaust brackets and perhaps to make it fit into the 500 engine bay without needing modification around the exhaust guard.

I couldn't get any paint for the rocker-cover, but in any case, I now need to refurbish a set of engine cowlings and an alternator so that I can test the engine properly. It's a really nice engine and I'm tempted to stick it in the car for a a thousand miles to get it nicely run-in and tested and so that I can compare the performance of the mid-capacity engine.

https://youtu.be/gXxKtcUPWfU

you had to hold on tight there Peter!

Must be very satisfying when it fired up. Congrats.

lazylobster said:

you had to hold on tight there Peter!

Must be very satisfying when it fired up. Congrats.

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Yes, it did try to bounce a bit; my previous rebuilt engines have always had the cowlings and gearbox etc for weight and stability. It is very satisfying when it goes so well without any messing about; i've learned a lot since the first one. But this engine just seems to have a lust for life...it was just as lively, (although very leaky), when it first arrived here.

fiat500 said:

Yes, it did try to bounce a bit; my previous rebuilt engines have always had the cowlings and gearbox etc for weight and stability. It is very satisfying when it goes so well without any messing about; i've learned a lot since the first one. But this engine just seems to have a lust for life...it was just as lively, (although very leaky), when it first arrived here.

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Crikey I’ve seen a few of these from you over the years! But this was by far the most entertaining! It looked pretty cluttered in there but towards the end everything was vibrating and moving about like crazy! The only thing that stopped the shopping basket with the glasses in from falling on the floor was because it ended up resting on the engine.

Was that a calor gas cylinder on the floor?

I like your bike btw!

Vitesse said:

Crikey I’ve seen a few of these from you over the years! But this was by far the most entertaining! It looked pretty cluttered in there but towards the end everything was vibrating and moving about like crazy! The only thing that stopped the shopping basket with the glasses in from falling on the floor was because it ended up resting on the engine.

Was that a calor gas cylinder on the floor?

I like your bike btw!

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Cluttered!....that's tidy...it's Sheila's small allocation of shed-space. The bikes's my professional training bike for LeJog. The startup was all rushed into a brief gap in time when Sheila,(who's working from home), shouted downstairs that she would be 15 minutes late for supper. The oil had just arrived and I couldn't be bothered waiting to shift the engine back into the garage, so I shot out and went into action.

I've had another go today and it looks quite promising. The tickover is excellent and underneath all that clanking atc. it's pretty smooth. The gas cylinder is empty so obviously it can't be dangerous. The open can of petrol that I don't think is visible might have had the potential to give problems. I had an extinguisher ready on the floor.

The part I can't be bothered with now is tarting-up all the cowlings etc. so I can test it properly; I'll probably just bodge it together and give it a try,

I know that you have been meticulous with keeping the engine internals clean but it will be interesting to see the oil when you first drain it. I know I used fully synth but the oil came out quite blackened after running in as it gets to the bits you can't.