Renault straight eight engine anyone..?

This I could definitely do in aluminium..
I'd just need to sort out the liners. :unsure:

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I remember reading the Bugatti 35 straight eight block was made by welding steel plates now that would be my preference.

And a nice DOHC head. Sidevalve is really one of those technologies best forgotten. Makes me wonder why Renault didn't do OHC at the time. Others were doing it already. Cost, maybe.
 
56 Fregate said:
Thank you David,
If, just for kicks I did attempt to build an engine from scratch I would def be using an existing crank and rods from a Yankee engine. Parts for American engines are available in great number in USA and perhaps parts could be found here as well. The length of the iron liners are a concern which exacerbates the thermal expansion differences between Al and iron leading to breakage or distortion but there must be a way to do it. Sourcing a genuine Renault engine has proven fruitless due to the number of units produced in the first place and remember Hitler melted everything he could get his grubby hands on while occupying France, including Renault engines. They are scarce and I live on the wrong side of the equator.

I note that almost all of the American engine producers had their ports on the RHS of the engine (look at my Dodge 6) whereas Renault were the opposite (see the original pics above). This means of course that the crankshafts are in opposite orientation between the two, but they can be made from billet no problem.

You are quite right about the amount of energy it would take to produce a cast iron engine block by the home hack sand caster but aluminium is definitely doable, I feel it in my waters. I wouldn't even consider outsourcing a casting to a commercial operator, that would kind of defeat the purpose.
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Renault sorted out steel or iron liners in alloy blocks with the R16 I guess. Perhaps the head gasket material was the key?
 
schlitzaugen said:
I remember reading the Bugatti 35 straight eight block was made by welding steel plates now that would be my preference.

And a nice DOHC head. Sidevalve is really one of those technologies best forgotten. Makes me wonder why Renault didn't do OHC at the time. Others were doing it already. Cost, maybe.
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Louis was in direct charge and very conservative. Just look how long they retained a rear-mounted radiator! And cost of course.
 
JohnW said:
Not a bad price..... Surely someone has a project for an engine like that. Pretty rare! I've heard the one in Renault's replica of the record breaking car - quite a modern-sounding engine, so I'm guessing a light flywheel.
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JW, here's another pic of the record winning Renault replica from 1934 and it'd def a Nervasport engine.

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Hi Graham :)
Being a Renault man from way back I would expect, nay demand, that you would use wet sleeves. Easy enough to do in an unstressed side valve engine like that design and I am sure you could find some suitable genuine Renault sleeves to use from some engine. Just a bit of careful machining of the alloy block ;)
Or you could use dry sleeves. Plenty of diesel engines use them for ease of reconditioning. Just a straight sleeve with a top flange clamped by the head gasket and no bottom details needed.
Jaahn
 
In the days before the introduction of leaded fuels, detergent oils , & regular decokes & valve grinds, side valve engines were easier, quicker & cheaper to maintain than overhead designs . My two pennith worth ! :unsure:
Richard
 
56 Fregate said:
The American straight eight manufacturers had a replaceable water distribution tube running right through the port area to keep the exhaust valves cool, it seemed to work.

View attachment 210359
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the citroen traction avant has that distribution tube in its head too. I wondered what the idea of it was!
 
After having seen the corrosion caused by cavitation in some alloy blocks around the furthest liner from the pump, I was considering a similar idea but with an external tube directly from the pump with staged outlets directly at the base of each liner. Bit involved but worth an experiment.
 
jaahn said:
Hi Graham :)
Being a Renault man from way back I would expect, nay demand, that you would use wet sleeves. Easy enough to do in an unstressed side valve engine like that design and I am sure you could find some suitable genuine Renault sleeves to use from some engine. Just a bit of careful machining of the alloy block ;)
Or you could use dry sleeves. Plenty of diesel engines use them for ease of reconditioning. Just a straight sleeve with a top flange clamped by the head gasket and no bottom details needed.
Jaahn
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Thanks for the input Jaahn,

You can demand all you want but I can't see how wet sleeves could possible be an option for a side valve engine given the shape of the combustion area. :D Nay I reckon dry liners are the go but at 4.8 mm thick I reckon there would be problems with distortion due to the different thermal expansion rates, but it has been done, check out Donovan engines he seemed to have made it work.
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Hmm nice work there ;)
But I might suggest for a side valve six there are far too many main bearing for the crank if you have 7. The crank will be too 'whippy' and they are not needed. 4 is enough and much easier to make. :rolleyes:Or investigate one from a common motor from some years back. EG a ford six was made in various strokes over the years.
The details of the sleeves may need a bit of 'polishing' before starting work :giggle:
Jaahn
 
schlitzaugen said:
After having seen the corrosion caused by cavitation in some alloy blocks around the furthest liner from the pump, I was considering a similar idea but with an external tube directly from the pump with staged outlets directly at the base of each liner. Bit involved but worth an experiment.
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Really cavitation? I honestly doubt that. Localised boiling due to poor circulation due to sludge maybe? Or coolant not changed properly? I'm no expert but the alloy block corrosion I've seen has been at the base (or side on inclined blocks like Peugeot 205/306, due to sludging and left full for years without running. They seem to do high mileages over long periods of time (our 16TS at 25-30 years with well over 200,000 km was fine) if the coolant changes are done properly.
 
I am not a specialist either and I don't claim to know the absolute truth but I think corrosion due to sludge takes a different form.

These blocks where I suspect cavitation was the culprit were corroded in very round localised spots almost like someone had plunged an 8mm diameter ballnose endmill into the block here and there and they were not only on the down side of the block. The "up" side had the same problem. Corrosion was localised around the base of the liners only and it was worst at the far end of the block from the water pump. Most importantly, these cavities were not connected. That is why I am inclined to discount sludge.

I have seen corrosion that may be due to sludge in Renault 807 blocks. That looked like trenches of inconsistent width around the base of the liners.

That said, my old 17TL had been left for quite a few years to rot under an orange tree. That is where I found it, oranges rotting everywhere on the shell. I fired it up and drove it for six years without changing anything in it. When I broke it up for parts, the block was perfect. Unlike my 17G that had regular servicing and it was an absolute basket case. Unuseable. I rebuilt the 17G engine with the TL block but still have the original in the shed.

I have also had a R18 block that had the most peculiar corrosion I have seen. Pockmarks like meteorite impacts everywhere, the sides, the bottom, front and back. A lot of them. No idea what that was about, probably poor quality alloy.
 
schlitzaugen said:
I am not a specialist either and I don't claim to know the absolute truth but I think corrosion due to sludge takes a different form.

These blocks where I suspect cavitation was the culprit were corroded in very round localised spots almost like someone had plunged an 8mm diameter ballnose endmill into the block here and there and they were not only on the down side of the block. The "up" side had the same problem. Corrosion was localised around the base of the liners only and it was worst at the far end of the block from the water pump. Most importantly, these cavities were not connected. That is why I am inclined to discount sludge.

I have seen corrosion that may be due to sludge in Renault 807 blocks. That looked like trenches of inconsistent width around the base of the liners.

That said, my old 17TL had been left for quite a few years to rot under an orange tree. That is where I found it, oranges rotting everywhere on the shell. I fired it up and drove it for six years without changing anything in it. When I broke it up for parts, the block was perfect. Unlike my 17G that had regular servicing and it was an absolute basket case. Unuseable. I rebuilt the 17G engine with the TL block but still have the original in the shed.

I have also had a R18 block that had the most peculiar corrosion I have seen. Pockmarks like meteorite impacts everywhere, the sides, the bottom, front and back. A lot of them. No idea what that was about, probably poor quality alloy.
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Strange, isn't it? The extreme corrosion on older Renaults before decent additives were available (first here with the R4 I think) was often seen as extreme pitting (water pump spigots for example). I've read that small localised corrosion cells can form quite quickly, but you do need a conductive fluid. Using good coolant and changing by the instructions since we bought the R8 in 1973 has worked pretty well regarding corrosion. We never had a corrosion problem on a 16 with regular coolant changes. So I do suspect the fluid is the problem.

I've just seen extreme corrosion within three weeks on an aluminium fitting in contact with swimming pool water (slightly brackish and with free chlorine). Amazingly fast!!
 
schlitzaugen said:
I remember reading the Bugatti 35 straight eight block was made by welding steel plates now that would be my preference.

And a nice DOHC head. Sidevalve is really one of those technologies best forgotten. Makes me wonder why Renault didn't do OHC at the time. Others were doing it already. Cost, maybe.
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Bugatti was quirky

Instructions for valve grind in some of his cars started with “remove rear axle”

OK if one has a team of slaves to maintain it I suppose

But still some of the most beautiful and effective cars ever made

Andrew
 
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