10HP Renault

[Alastair]

Many years ago I bought the remains of a 10HP Renault dated November 1911.  Now that COVID 19 has struck old projects come to the fore so I have turned my attention to the engine.

The remains came with a splendid Renault carburettor weighing almost half the weight of the engine.  I have yet to get to grips with it.

However, also included in the deal was another carburettor made by Harno.  It is bronze bodied and of 28mm throat diameter.  It has a bottom fed float chamber and an unusual air inlet system.  This comprises a central tube of about 8mm diameter surrounded by a spring loaded valve filling the rest of the inlet port.  The compression of the spring behind the valve is adjustable by means of a splendid knurled nut.  The carburettor has a conventional butterfly throttle, which therefore limits how old it must be.

Does anyone know anything about Harno carburettors?  I cannot find them on Google.

[MatchFuzee]

Have you tried Renault? 

https://group.renault.com/en/our-company/heritage/

[Alastair]

Thanks for the link.  I already have the handbook for the Renault carb.

[Alastair]

A little progress over the week end.

There was a hole in the cast aluminium sump where the engine had obviously been stored against something metallic that had reacted with the aluminium.  I had been pondering on how to fix this and was coming to the conclusion that patching it would be safest.  However, I had some Lumiweld sticks around so decided to give it a try.

I used a propane blow lamp and played it on the sump for a very long time before it was up to temperature for the repair.  It is quite difficult to get the Lumiweld to wet the surface of the aluminium but persistence and lots of scratching the surface through the molten Lumiweld, using the stainless steel wire supplied, managed to do it.

[Alastair]

So I have had an adventurous time with the Renault engine over the last two days.  I have no information on the engine and have never worked on one with a separate crank case but how difficult can it be!!

The main bearing locating pegs are in the sump half so the crank shaft must be assembled with its con rods first then, with its bearings, dropped into the sump.

The crank case is surprisingly heavy for cast aluminium so has a tendency to drop suddenly when the two long centre main bearing studs are located in the holes in the sump.  I did all this after I had used instant gasket on the flanges.  I did up the main bearing nuts and the twelve sump flange nuts and bolts.  It was only then that I noticed that one of the con rods, instead of coming up through its designated hole in the crank case top, was poking out of the hole for the cam followers.  I removed the whole lot once more and, by means of a cunning set of pieces of string through the little ends, I got it re-assembled and buttoned up.  I knew that the oil pump drive shaft had to be loosely dropped onto its hole before the cam shaft went in so I approached the engine with this and found that it has to go in the sump half before the crank case is lowered on as it will not pass through the top deck.  I undid it all once more.  The oil pump drive shaft now in place in the sump, I assembled the crank case once more and buttoned it all up.  I fitted and timed the camshaft.  All the while I had a bad feeling.  There was a spare cog that the chap who sold me the car told me was a spare timing cog.  I was puzzled as I could neither see where it might go, nor could I see what it might mesh with nor could I think of anything that needs driving other than the oil pump and magneto, both of which are catered for.

Then the penny dropped, the cog was not supposed to mesh with anything.  In fact it is an oil thrower to be fitted to the back end of the crank shaft.  I stripped the engine once more and fitted it.  It was a rattling good fit as the machining of the rear main bearing surface had also reduced the diameter of the crankshaft where the thrower was supposed to be a press fit.  I used some Locktite but am certain that at some future time I will be posting news that I have had to take the engine out in order to fit the thrower more positively.

I am now making a missing brass plug that is suppose to enclose the front end of the camshaft.

[Alastair]

I got a  little ahead of myself when I started this thread.

I had already had the bearings done by Fields Engineering Services in London.

Before I did anything else I had to drill out four of the nine studs in the front flanges of the crank case and sump, where the timing case fits.  Strangely, they had all broken so as to leave half their threaded portion in the holes.  This turned out to be a blessing. I drilled three 8mm bolts down their centres to act as drilling guides and was able to use the remaining thread to hold them in position.  When the pilot holes had been drilled, I had the awkward job of aligning the crank case and sump, in turn, absolutely vertically at the pillar drill so as to drill the final size holes for the thread inserts.  I was concerned that the studs would be on the wonk and the timing case would not go on, if I got this stage wrong.  It all turned out all right.

Anyway to return to yesterday, I commenced to make the closing cap for the timing case where the cam shaft is supported.  I am of the belief that I never take exercise and have the lack of fitness to prove it but the first task yesterday was to find a bit of brass that was big enough for the job.  All I have is a bar 68mm in diameter.  This was too big for my power hacksaw so I had to cut the desired length off by hand.  It took me 45 minutes of continuous sawing hence the comment about not taking exercise.  I needed 50mm diameter but that was all I could find in stock so I am going to be up to my knees in swarf.  I have no idea what the original cap would look like so I decided to flute the flange both for looks and to help installation.  To do this I mounted the piece in a dividing head and drilled 10 holes.  Then I ran out of time for the day.

[Alastair]

The Father of a good friend of mine is a keen model engineer.  He says that it is not possible to make a single traction engine model.  You always make two but one of them is in the scrap bin.

Well making the blanking plug for the timing case of the Renault engine was a bit like that.  I miss-counted the teeth on one of the change wheels and, consequently, cut the wrong thread.  However, it all, turned out all right.  As I said above, the shape is entirely of my own invention as nothing important is going on inside the plug i.e. it is not providing a support bearing. Having said that I decided to make it look important by giving it a dome.  I did this using a profile I had made for another job.

The next stage is to remove various broken off studs in the cylinder block.

Does anyone know the whereabouts of a radiator for a 1911 Renault?  Mine is missing (weighed in for its scrap value we think).  The condition is not important as I am considering making one but I need something to start from.  Otherwise that too may end up with castillations and a big blob on the front!

[Alastair]

A little more progress in the last two days.

As previously mentioned, I had to remove the remains of the central stud that had held the cold water inlet elbow on the side of the block.  This had evidently rusted right through (as have a series of studs that hold the top water jacket in place) but to complicate matters, someone had tried to drill it out free hand and placed a pilot hole off centre.  Given that drills are pretty flexible and pointy, it would be inevitable that the enlarged hole would also be off centre if a drill were used.

The saving grace, to my mind, was that the orifice for the intake elbow was nicely machined and I therefore assumed that the stud hole would have been drilled using a jig that picked up the machined hole.  In this case I could make a drilling guide that sat snugly on the hole and use an end mill to give me a reasonably sized pilot hole.  This I did and then used the same jig (after tweeking) to guide the tapping drill.  the result was astonishing.  I was left with a hole with just the thread of the original stud sitting smugly in the thread of the hole in the block.  I have only once before had this amazing experience and I take my hat off to the Renault machinist who made the thing in the first place.  The draw back is that I have so far been unable to catch the thread and spring it out but give me time.

The second job should never have been necessary had I made a note of the orientation of the pistons when I separated them from the con rods.  I know that there would be a right and a wrong way round for them.  Fortunately I also knew that the gudgeon pin is offset towards the thrust side of the piston.  So I placed two gudgeon pins in a piston, sticking out the sides the same distance and measured the height of the end above a flat surface when the other end was on the surface.  I turned the piston over and the offset was clear.  I now know that the number stamped on the top of the piston goes to the front.  I knew all along that this was the convention but who knows what was going on in Billancourt in 1910.

[TonyB]

A great project Alastair, I enjoyed reading about your progress. It echoes my own experience of bolting up and then undoing several times to find the way forward.

Do you know if your 10HP engine is similar to that used in the 6 wheeled Renault (Type MH)  sometimes called 10cv and/or 13.9 HP? It is interesting how they competed with Citroen half-tracks for Sahara crossings and the bitter rivalry it caused.  

[Alastair]

I can not answer your question definitively but I do know that the French calculation of horse power was different to ours.  The capacity of the engine is about 1.68L so would be anything up to 14HP in the UK.

According to "The Renault File"  the 6 wheel 10CV Sahara car of 1923 everything is similar except for the fact that it is 5027cc capacity (100 bore x 160 stroke).  Interestingly it had rack and pinion steering, which must be an early example of that form.  The designation MH is not mentioned but a 20CV version of 1927 was designated the Type OX.

[Citroman]

I did see radiators turn up several times at the Reims oldtimershow. And yes they are large beasts completly in brass tubing.

Edited June 27, 2020 by Citroman

[TonyB]

4 hours ago, Alastair said:

I can not answer your question definitively but I do know that the French calculation of horse power was different to ours.  The capacity of the engine is about 1.68L so would be anything up to 14HP in the UK.

 

That’s a good point about the different French calculation which I had forgotten. I just checked another source which said the Type OX 100 x 160 (1600 rpm) was 20 CV, but that was used from 1926 for the trans-Saharan transport and they called it a monoblock engine. In 1922/3 they used the 10HP HP and perhaps called it an MH.

But what is interesting for me is to see your engine being rebuilt and how different the Renaults were from the Citroens in the desert at the time. Your work does you credit, great pics.

[David Herbert]

Looking back through this thread I see only four holes in the crank case for valve tappet guides. I am guessing that the inlet valves are opened by suction against a very light valve spring ?

David

[Alastair]

All 8 valves are mechanically operated. The four holes you can see each take an assembly with two guides for two cam followers. I'll include a picture next time.

Alastair

[Alastair]

Thanks for the encouragement Tony.

I do not know much about the contemporary Citroens. I once saw one with a  1924 clover leaf  body but no engine.

Alastair

[Alastair]

David,

 

Here is a picture of the top deck of the crank case.  It shows the eight cam followers I was trying to describe earlier.  Between the two sets of four can be seen the top hat bearing for the oil pump drive shaft.  To the right, the brass tube is a sight glass in which an indicator could be seen (if I had taken the picture from a favourable angle).  This is a brass ball on top of a rod which emerges from the sump.  The rod is attached to one end of a bar that pivots at the other side of the sump and has a float in the middle.  Thus the indicator gives the level of the oil in the sump.  I do not believe this feature was continued for long.

The only work I have done since my last post is to prime the cylinder block with Bondaprime.  The original colour was a dark grey.  I will try to copy this but acknowledge that it will not look as nice as the black or red paints more often used in restorations.

Meanwhile, putting up a new fence has unfortunately come to the top of the to-do list.

 

Alastair

[Alastair]

The fence is progressing well but yesterday had a number of rain squalls.  I took this as nature's way of saying I should work on the Renault engine.

I found the correct grey colour and have been painting the cylinder block and other bits and pieces.

I decided that it was time to fit the pistons.  You will see in the picture below that the rings are very wide by today's standards.  I was missing a ring from each of two pistons so have had to fit double narrow rings in place of the wide ones.

the pistons otherwise are unusual (to me) in that the gudgeon pin is held on place by two tapered bolts into slots.  I suspect that there may be a bit more to it as there are vestiges of a thread on the narrow end of the taper.  These are in a poor condition.  This must mean that the bolts are machined to fit a particular piston but when they get swapped around the narrow thread at the end gets mashed.  In my case I think there has been a lot of swapping around as I noticed that the gudgeon pins are stamped with the piston number in some cases but are no longer in those pistons.  The result is that the bolts do not all go home by the same amount.  For safety the bolts are cross drilled at their heads to take a split pin the head of which stops the bolt from turning.

One piston caused me some problems.  The gudgeon pin had been hit rather hard on one end which had slightly belled the end.  the result was that it would neither come fully out nor would it have been possible to fit the conrod and slide the gudgeon pin into the opposite boss.  The only way I could dress the end was to hold the gudgeon pin in the lathe chuck and, after selecting slow speed and holding the piston in my left hand, I was able to dress the pin with a stone.  I really do dislike getting carburundum anywhere near the lathe or a piston for that matter but since the gudgeon pin is so hard I would never have been able to rectify matters using a file.

Now all four pistons are fitted to their con rods I just have to fit the split pins to the bolts.  I can see that I will need to have a neck like an anglepoise lamp to see what I am doing.  Maybe the pistons should have been fitted to the rods long before any assembly of the engine was attempted.

[TonyB]

Good work Alastair, and a good read. Cast iron pistons? I had to choose whether to use the original CI pistons or later aluminium ones. Everyone told me to use the ali ones but I wonder. My little 1400cc Citroen engine has bronze mains and big ends so it was set up for the heavier CI kit, plus a mighty flywheel. My CI pistons have three wide rings too which I believe conduct the heat from the piston crown efficiently to the block and its coolant. They also fit more snugly because they expand at the same rate as the block, unlike ali.

Power to you elbow.

[Alastair]

Thanks for the support, Tony.

Yesterday I did a number of small jobs (more broken studs etc.) and one major one.

With the help of my brother Peter and a chain hoist, we dropped the cylinder block down and inserted the pistons.  I have left it an inch up as I want to spend some time checking that the mating surfaces between it and the top deck of the crank case are still spotless.

Right at the beginning I confessed that I had never worked on an engine of this type (cylinder block+crank case+sump) before.  I now know that it would have been much easier if I had built it upside down.  Firstly the top surface of the cylinder block is flat so the whole would have been steady (see my cunning engine stand in the picture below).  Secondly, having attached the pistons to the con rods, each piston could be inserted into its bore easily. Then the crank case would be dropped on top, the crank shaft inserted and the sump attached.  It is true that the engine is best turned over to sort the valves out.

[TonyB]

Solid work, Alastair.. I think that I have built three part engines in most ways over the years, and once in the vehicle because I didn’t have a hoist to lift the complete engine which was too heavy to lift in by hand. Pros and cons for each method.

I would have liked to see the timing cogs, were they marked? And, given your skills, where are the elegant feet for your cunning engine stand?

[Alastair]

Tony.  I buttoned the timing case together without photographing the timing marks.  The crank shaft gear is steel and is keyed on and then a taper pin is fitted through both parts.  Unusually, the taper pin has provision for a split pin at the narrow end.  Maybe Renault had problems mating the tapers of the holes to the pins so added the belt to the braces.

The cam shaft gear is made of brass.  The crank gear has a scratched mark between two of the teeth and the cam gear has a center pop on one of the teeth.  Lacking any other marks, and not having made any myself when I took the engine apart, I used these to time the cam shaft.  The result is credible but I will check with a dial gauge when I have fitted the valves.  I must go back to the Peerless thread to remind myself of who supplies springs.

President Kennedy famously said, "We are going to the Moon not because it is easy but because it is hard".  In other words for the challenge.  I think that this sums up our hobby quite well.  We take a vehicle which is clearly beyond economic repair (or worse) and set about repairing it for the challenge.  For example, having made new stainless steel studs for the places where the studs pass through the water jacket, I was missing the nut for the cold water inlet elbow.  Presumably this was lost when the stud rusted through.  The three nuts on the top of the engine are of a particular shape and style so, rather than use any old domed nut, I spent most of a day (I am a very slow worker) making a replica.  I'm pleased with the result.

I did not have much time for the Renault today as I had to make a new top for a barrel (I won't explain why).  However, I did have time to ponder on the caps over the valves where the spark plugs go (I do not know what these are called).  I am going to have a problem here.  Each of them is supposed to have a copper/asbestos ring gasket and I do not have a clue where to get such a thing.  The ID of these rings is 66mm and they are about 2mm wide.  It occurred to me that an old head gasket off a car that has a bore of 66mm could be carefully cut up to provide said rings.  I will try googling likely cars instead.

As to feet on my engine stand - do not tempt me.  It is just the sort of thing I would get up to but make them all Left feet!

[Citroman]

Your domed brass nut looks a much like a Michelin wheelnut.

 

[Zuffen]

Try exhaust flange gaskets of the appropriate size for the copper/asbestos gasket.

[Alastair]

Why didn't I think of that?

[TonyB]

Thanks for the description of the Renault timing mechanism Alastair. While modern adhesives and materials have replaced the keyways and machining of early engines like yours, it is always a joy to make them work. My flywheel has top and bottom dead centre marked but it isn’t keyed to the crankshaft, plus it has ROA and RFA??.  Stuff gets in the way, like your fence painting I have several tons of floor to put in and our local labourers have `gone Covid`. That seems to mean they aren’t available or cost twice the price, so I’m chugging away at it with little time for anything else.

Regarding the gaskets for your plug caps, I’ve seen them sealed in with stove gasket paste or stove string, looks messy and I suppose was once asbestos. Also crushable copper washers. Perhaps the Vintage Car Club would have a supplier, but Zuffen’s exhaust gasket idea sounds good if it will stand the twisting motion when the cap is fitted.

Citroman is right about the wheel nut similarity, mine are 19mm nuts marked G (gauche) and D (droit) on 14mm studs. They used lots of left hand threaded nuts. Just right for your engine stand.