Ultimate 807 build

21571

21571

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Hi All,

Given the amount of time we have to ourselves at the moment, perhaps we could use it for good rather than evil. Good being coming up with the ultimate 807 engine, budget no object.

Things to think about:

Bore and stroke, including pistons rods and crank. Is the crank a modded unit, pinched from a 2.0 Clio as has been done here and O/S or just a custom billet unit.

Head, ported& polished, domed like in the 807 pistons thread. Roller rockers?
Some 16V twin cam head adapted from somewhere.....What cam specs for street or race.

Induction, turbo or supercharger, carbies or injection, ITBs or R17G system.

Ignition, stick with a dizzy, electronically controlled or individual coils on the plugs?

Need a gearbox to support that too. Any Renault box up to the job or something else needed?

Remember, no budget!!!

And go!
 
OK I'll say a little.

I do not have the experience or knowledge, practical or theory to do much more than I've done already. What I mean is I don't know if there is a 16v head close enough to make it fit etc, etc. I mean what you want from this thread is at least something that will fit or is known to fit, not just grabbing things out of thin air.

I have done 2 x 807 engines, 1795 and 1604. The 1795 made 195 hp on a flywheel dyno at almost 8000 rpm. That was obviously de-tuned for the Targa rally because it had to last between 700-800 km of special stages.

This was achieved with the normal 8v head, Gordini rods and oil pump. The crank, standard, only lasted for 2 Targas (1400 - 1600km) when cracks were showing up and had to be replaced. I must admit that the biggest drawback on these engines is the 8 valves. A standard 16 valve head flows 40% more air than an 8 valve head. The build has been posted in a thread on AF already so I won't do it over.

This is an amateur video about the 1800 and a good idea can heard at about 40 seconds in when it was on full song. From this video it can be seen that it pulls strong, even at steep inclines.

https://www.youtube.com/watch?v=5ZOlnEPH5p8

The photo is the Dauphine powered by the 1600 engine.

Frans.
 

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Hi :)
Well after watching that guy with the V12 "mods" all that is needed to get a 16V head(or even 20V ?) is to machine away the current valves, ports, rockers, plugs etc. Then weld up new ports, water passages, plug hole etc etc etc and then machine them all perfectly as you want. Why not DOHC too :clown: And make your own cams to suit.

Should get that done by next month if you start now :eek: I was amused by this bit "The engine simulator (dynomation) thinks" How the hell could any program know what that might do. Did it check for only 11 cylinders running. :crazy:

Interesting though, thanks for posting it.
Jaahn
 
That grassroots link above.

Dear God!
 
Why so much work.
Honda has done it all already.
Sweet DOHC VTEC
Crate engine just fit is in and GO

honda.jpg
 
Four problems. One would be the mountings. Two the clutch to gearbox Three, getting it through Machinery. And four, for me $$$$. Of course nothing is impossible and it sure looks nice.
 
The Honda is shiny, but I'd like to keep the alloy block of the 807 in place. It's a die cast thing of beauty.
An easy swap could be F4R f from a Clio, but it's a cast iron block.

What are the bore spacings on an 807?

I quite often look at the big empty space on the exhaust side of the engine bay of the A310 and wonder what sort of forced induction type thingo could fill that space....

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21571 said:
The Honda is shiny, but I'd like to keep the alloy block of the 807 in place. It's a die cast thing of beauty.
An easy swap could be F4R f from a Clio, but it's a cast iron block.

What are the bore spacings on an 807?

I quite often look at the big empty space on the exhaust side of the engine bay of the A310 and wonder what sort of forced induction type thingo could fill that space....

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Click to expand...

I don’t think the F4R would be an easy swap, and the turbo 807 has already been done in the Fuego Turbo. Injection in the US and a pressure fed carb in the UK. The turbo 807 head has much smaller ports than the NA version.
 
alan moore said:
I don’t think the F4R would be an easy swap, and the turbo 807 has already been done in the Fuego Turbo. Injection in the US and a pressure fed carb in the UK. The turbo 807 head has much smaller ports than the NA version.
Click to expand...
Turbo technology has come a long way since the early 80s. With modern computers you can make a turbo do anything. There's Honda powered cars with the engine like above pulling 1200hp and 8 second 1/4m.

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alan moore said:
I don’t think the F4R would be an easy swap, and the turbo 807 has already been done in the Fuego Turbo. Injection in the US and a pressure fed carb in the UK. The turbo 807 head has much smaller ports than the NA version.
Click to expand...

21571 said:
Turbo technology has come a long way since the early 80s. With modern computers you can make a turbo do anything. There's Honda powered cars with the engine like above pulling 1200hp and 8 second 1/4m.

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Click to expand...

What about a turbo 807 with the injection from an R17TS and modern programmable ECU?
 
COL said:
What about a turbo 807 with the injection from an R17TS and modern programmable ECU?
Click to expand...
That's an easy way to 250hp+, or whatever the weak point is, has @brettr8 found his yet?
Many engine tuners believe boost is cheating, so how to get the HP without it?
Bore, probably maxed out at 84mm, but there are ways of going higher as a couple on here know.
Offset grind the crank for a couple more mm. The stock journals are generous.
Clio 2l crank? Drops the stroke to rod ratio to a figure considered low. Need some very low compression height pistons too. Can and has been done.
A custom billet crank, modern rods and pistons will drop reciprocating mass way below what was possible in the 70s.
How to reduce internal friction? Alloy roller rockers, carbon fibre push rods?

C'mon!!

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I don't quite understand the need for more power. I mean you're not trying to plough the field, right?

Why not enjoy the car as is and try to see how good you are instead? Sure, it's tempting to try to beat the Nurburgring lap record, but in my eyes, if you score a good lap the comparison doesn't matter and it doesn't matter what you did it with. So why not try a car as it came from factory? Especially if said car has some decent power in stock form.

And if you want more power why not go all out and design your own engine. Make it two stroke turbo charged and supercharged and run it on nitromethane. Done.

That said, I would love a chance to see that 2L V12 Ferrari engine used in the early Berlinettas (?) in person. You've got to love small capacity engines with lots of tiny cylinders.
 
21571 said:
Looks like some of the hard work has already been done, who's familiar with the 807-G4? DOHC and 16V!!!

https://silodrome.com/alpine-renault-a110/
https://www.classicdriver.com/en/car/renault/alpine/1974/729645

Seen more plentiful rocking horse poo though.......
Click to expand...

There you have the ultimate motor based on a 807.

There were a few 16 valve heads made by I know of 4 builders. They put out between 195HP and 207HP, and the different torque characteristics made the one to buy. One of the less powerful was the choose of many because it had a very "fat" torque band and didn't rev quite as high making it more durable. Of all of them I still cannot understand that they continued running the water pump and alternator off of the cam at the flywheel end of the motor.

The most important step to go to this kind of HP and torque was forged or billet machined steel crankshafts. All of the above PH readings were all on Fuel Injection. Some hand made. And would have run on Avgas 101 0r 105.

The G4 car in the artical, was on a car and equipment show near Coventry UK and they had about 40 classic rally/cross cars doing demo runs on a tarmac/dirt course. The Alpine sounded like a modern race motorbike, with very respectable times compared to Audi Quatro, Lanci Stratos, and Ford rear engine. A great day in the country.

Ray
 
schlitzaugen said:
I don't quite understand the need for more power. I mean you're not trying to plough the field, right?

Why not enjoy the car as is and try to see how good you are instead? Sure, it's tempting to try to beat the Nurburgring lap record, but in my eyes, if you score a good lap the comparison doesn't matter and it doesn't matter what you did it with. So why not try a car as it came from factory? Especially if said car has some decent power in stock form.

And if you want more power why not go all out and design your own engine. Make it two stroke turbo charged and supercharged and run it on nitromethane. Done.

That said, I would love a chance to see that 2L V12 Ferrari engine used in the early Berlinettas (?) in person. You've got to love small capacity engines with lots of tiny cylinders.
Click to expand...
It's not all about absolute power, I'm interested in all the 1% tricks and engineering that add up to a proper engine.
We all know about the laws of diminishing returns, but with no budget I want to investigate them all.

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I think that road is pretty well mapped out by now. And no, I wasn't talking about the point of diminishing returns. My point is, pretty much everything that can be done to an engine to extract as much power as possible has been (and continues to be) done already by qualified and well paid engineers at the factory. F1 technology has been for a long time the test bed for innovation that is soon transferred into consumer products (and we are very thankful for it, in fact some cars are so good, you don't need to have the unicorn that spawned it, because that was fragile, whimsical, difficult to put up with and needed a rebuild every 100km or so, whereas the road going version sold to the public is 99% there but without any of the hassle).

One starting point is to look at what Frans has achieved. His engines/cars are pushing the limits in the most literal way you can imagine and with amazing results but you wouldn't want to live with one of those cars daily. I also remember Dave Cavanagh once commented the 12G he had restored and driven for some time was a dog in traffic.

Anyhoo. Interesting discovery (for me) to see that Renault in fact had already developed the 807 to its limits. I didn't know these 807 based DOHC engines existed, but I did realise that if you wanted more power that was the way. This idea came to me some time ago mainly looking at Frans' builds pushing (and hitting hard) the limits as I said. How much does he get right now? 120HP per litre or so? That is probably the most you can ever hope to get out of a N/A engine (and at some serious cost to reliability) hence my suggestion in jest above with a two stroke supercharged and turbocharged (how much was Renault getting out of their 1.5 F1 engine in the seventies? pushing 1000HP or so?).

Interesting thread nevertheless for us neophytes to see what else is available for our beloved donks though next stop I guess is electric.
 
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