A Real Dauphine !!!

dauphproto said:
Yes the pistons have the Wrist pin 3.5mm higher. Remember it is a hemi with stepped liners the space available above the pin and below the Step is full of rings with nowhere else to go, also the crown height is still quite high. The engines actual configuration places several constraints on what you can do. Edit See Caption Below.
Click to expand...
I had forgot about the stepped liners. From what I can see the step is about where the upper ring will be on the pistons I plan to use at tdc.
 
Reidar said:
Why is that? I guess your pistons have about 3,5mm lower compression height to compensate for the extra throw. Can the pistons not be made even lower to compensate for extra rod lengt?
I know of examples where the Cleon based Brasilian CHT1600 witch have 83,5mm crankshaft have been modified using the 138mm conrods from CHT1000 and 25mm compression height pistons.
I plan to build a C2J(super 5) engine in the same fashion with BMW Mini w11 pistons
Click to expand...
The conventional wisdom is that rod length to stroke ratio shouldn't be less than 1.7. In the early 1960s, Ford stroked the 997cc Kent engine to 1340cc without increasing block height. They used the same pistons with shorter conrods.
Because of increased 'rod angularity', the 1340cc engine was not as 'sweet' as the 997cc version. However, together with other performance mods, it did marvels for the performance of my105E Anglia!
 
Standard Renault Ratio is 126/77 giving Ratio of 1.63. 1700 has 126/84=1.5 It is possible to get long rods on 131/77=1.7 you need to use the low deck piston to make this work.
Most modern small std car motors today in the 1.5 range for good mid range (they have no top end anyway) which helps economy. one of the main benefits of long rods, other than less angularity, wear and stress,is the piston hangs around at TDC a bit more which helps out combustion at high rpm. it is worth remembering that this is outwith most of what we do with our type engines revwise.
It certainly lifts under load well and once above 4000 it's away, just need to see what it feels like in the car - should be fun.
 
dauphproto said:
Standard Renault Ratio is 126/77 giving Ratio of 1.63. 1700 has 126/84=1.5 It is possible to get long rods on 131/77=1.7 you need to use the low deck piston to make this work.
Most modern small std car motors today in the 1.5 range for good mid range (they have no top end anyway) which helps economy. one of the main benefits of long rods, other than less angularity, wear and stress,is the piston hangs around at TDC a bit more which helps out combustion at high rpm. it is worth remembering that this is outwith most of what we do with our type engines revwise.
It certainly lifts under load well and once above 4000 it's away, just need to see what it feels like in the car - should be fun.
Click to expand...
Is not the standard rods 128mm?

It is not my intention to pick on you. I must admit I read more then I work on cars and reading your stuff during the years have been a hoot. Food for thought and dreams.
 
Reidar you are quite correct std rods are 128 and long rods are 131. I'll edit the previous post
dauphproto said:
Standard Renault Ratio is 128/77 giving Ratio of 1.66. 1700 has 128/84=1.52 It is possible to get long rods on 131/77=1.7 you need to use the low deck piston to make this work.
Most modern small std car motors today in the 1.5 range for good mid range (they have no top end anyway) which helps economy. one of the main benefits of long rods, other than less angularity, wear and stress,is the piston hangs around at TDC a bit more which helps out combustion at high rpm. it is worth remembering that this is outwith most of what we do with our type engines revwise.
It certainly lifts under load well and once above 4000 it's away, just need to see what it feels like in the car - should be fun.
Click to expand...
Unable to edit post so have corrected it above can't think where 126 popped up from ......... It's my age you know..
 
Regarding rod lenght to stroke ratio on Sierra engines Oettinger made a special version 1,6L version of the Volvo 340. This was achieved by increasing the stroke to 87mm. The bore was still 76mm. The fact that they did not increase the bore lead me to belive they used stock pistons and a shorter then standard conrod. If I’m right the ratio was 123/87=1,4.
 
Reidar said:
Regarding rod lenght to stroke ratio on Sierra engines Oettinger made a special version 1,6L version of the Volvo 340. This was achieved by increasing the stroke to 87mm. The bore was still 76mm. The fact that they did not increase the bore lead me to belive they used stock pistons and a shorter then standard conrod. If I’m right the ratio was 123/87=1,4.
Click to expand...
That's interesting. The pistons would have been a bit taller wouldn't they?
 
John the Piston crown would have to be lower, or the Wrist pin needs to be higher, both have limitations. I was assuming (what you should never do) That everybody knew the Cleon C was enlarged in Renault 5 Turbo (mid engine) from 1397 to 1500ish by stroking to 84mm in conjunction with the F1 RE20B con rods for the maxi versions of the engine which had about 350-370bhp max on 3 bar and water injection.
I assume the bore was not enlarged to keep nice thick liners to deal with the pressures inside the engine. 84 stroke is about as big as you can go without having to clearance the block, in fact I had to clearance mine due to the steel rods which have a bigger width at bottom than standard rods which will just squeeze in. Dacia did a production 1500 on the Cleon C with 83.4 or 6 stroke which was the pattern I gave to Farndon to make my 84mm Crank.
I think the Volvo you are talking about was also Blown which would explain the Dynamics a bit. Old turbo motors did not rev high, not past 8k anyway which is low by race engine standards, so perhaps it achieved what they were after, something very powerful in the 3000 - 7000 range.
I think part of the reason my 1700 is not much higher in the power stakes than the 1550 is that I cannot fit in any bigger valves in, unless I Bore it bigger. When you have an 85mm centre motor bored at 80.5 there ain't nothing left. That said it is impressive in the mid range compared to the 1550 as always you can talk it around in circles for ever, there is only one way to find out....
 
dauphproto said:
John the Piston crown would have to be lower, or the Wrist pin needs to be higher, both have limitations. I was assuming (what you should never do) That everybody knew the Cleon C was enlarged in Renault 5 Turbo (mid engine) from 1397 to 1500ish by stroking to 84mm in conjunction with the F1 RE20B con rods for the maxi versions of the engine which had about 350-370bhp max on 3 bar and water injection.
I assume the bore was not enlarged to keep nice thick liners to deal with the pressures inside the engine. 84 stroke is about as big as you can go without having to clearance the block, in fact I had to clearance mine due to the steel rods which have a bigger width at bottom than standard rods which will just squeeze in. Dacia did a production 1500 on the Cleon C with 83.4 or 6 stroke which was the pattern I gave to Farndon to make my 84mm Crank.
I think the Volvo you are talking about was also Blown which would explain the Dynamics a bit. Old turbo motors did not rev high, not past 8k anyway which is low by race engine standards, so perhaps it achieved what they were after, something very powerful in the 3000 - 7000 range.
I think part of the reason my 1700 is not much higher in the power stakes than the 1550 is that I cannot fit in any bigger valves in, unless I Bore it bigger. When you have an 85mm centre motor bored at 80.5 there ain't nothing left. That said it is impressive in the mid range compared to the 1550 as always you can talk it around in circles for ever, there is only one way to find out....
Click to expand...
Thanks for that. As it happens, I'm tracking/watching a mid-engine 5 Turbo restoration about 20 minutes from here! Fascinating. Somewhere in front of a huge gearbox and underneath a tangle of pipes etc etc is a Sierra/Cleon block! Amazing.

Regards
 
Busy putting the Dauph back together again. Hopefully it will be better this time than last
Paul Errington was out in the Turboterrific R8 and filmed it. I'll add the link here
Honestly its a great conversion and quieter than a Stadard 8.......
 
Paul's R8 sure sounds nice , lots of mid range torque. Presume it is a Swan big 5 speed.
Any history of Paul's R8 build ??

Loved driving UK country roads !!!

Thanks Steve
Ray
 
Oh, I expect that's much better than most things on telly.
 
You must log in or register to reply here.
Top