Help with engine specs and layout

[abcmorgan]

Hi folks,
It's been a while since I've posted to the forum. I am still saving for the purchase of a mill and a lathe so in the meantime I am trying to keep byself busy with Solidworks. I hope somebody can help with the following...

I've got the following information on the Cosworth DFV engine from historicengines.com :


[size=10pt]Crankcase:
Description: 90° V8 crankcase and cylinders cast together in aluminum. Wet cast iron cylinder liners sealed with O-rings. Steel,
coated iron, and nikasil alloy liners were also tried. Nikasil alloy liners saved 8 lb in overall engine weight, and were standard by
1983.
Weight (with clutch): 370 lb / 168 kg
Overall width: 27.0" (686 mm)
Overall length: 21.5" (545 mm)
Bore: 3.373" / 85.674 mm
Stroke: 2.555" / 64.8 mm
Bore spacing: 4.100" / 104.1 mm
Deck height: 6.505" / 165.2 mm (crankshaft centerline to deck surface)
Crankshaft height: 5.23" / 132.8 mm (crankshaft centerline to external sump bottom)
Cylinder stagger: 0.375" / 9.5 mm (left ahead of right)
Materials: Cast aluminum block and head, forged steel crank and rods (earliest DFV cranks were billet), forged aluminum pistons,
cast magnesium covers.
Firing order: 1-8-3-6-4-5-2-7
Compression ratio: 11.0:1 (approx.)
Fuel: 101 octane (M.M. - motor method) minimum
Rotation: clockwise when viewing front of engine

Crankshaft:
Description: single plane ("flat") common throw (2 rods per crank pin, no offset), forged nitrided steel (earliest cranks were billet
steel), 5 main bearing crankshaft, hollow crank pins, weight 32 lbs / 14.5 kg, thrust taken on #3 main bearing, 8 bolts on flywheel
flange.
Main journal diameter: 2.3755" to 2.3750" / 60.3 mm
Rod bearing diameter: 1.9370 to 1.9375" / 49.2 mm (same as Cosworth FVA: Bearing is Cosworth part number FA0067)
Connecting rod journal diameter: 1.9375" / 1.9370"
Crankshaft: End float: 0.004" / 0.009"
Connecting rod side clearance (big end): 0.006" / 0.012"
Piston :
Description: forged aluminum, 4 valve notches. Full floating wrist pin.
Piston compression height: 1.469 / 37.3 mm
Weight: ~328 grams (with rings, without pin)
Ring width:
top: 0.0315"/0.80 mm
middle: 0.0410"/1.04 mm
oil: 0.160"/4.06 mm
Piston ring gap (all rings): 0.017" to 0.022"
Connecting rod:
Description: forged steel, H-beam, fully machined connecting rods.
Bolts: 3/8" UNF
Connecting rod length: 5.23" (132.842 mm)
Wrist Pin length: 2.500" (63.5 mm)
Wrist pin diameter: 0.812" (20.638 mm)
Wrist pin end float: 0.000" ± 0.001" (retained by clips)
Rod/Stroke ratio: 2.05[/size]


I am attempting to begin modelling in solidworks but I think I am probably going wrong somewhere. Please bear with me as I am still getting my head around a lot of engine terminology. In the following picture I think I have put in all the dimensions properly (I think) but if you look at the Deck Height it does not even clear the center of the wrist pin diameter:

I was not sure about what some terms such as deck height and compression height referred to so I have been using these diagrams that I found online:

The distance the deck height seems short by is curiously close to the dimension for the piston compression height. Anybody any pointers on where I could be going wrong? ???

 

[stevehuckss396]

No you are not nuts. There are some bad numbers somewhere. With an 8 inch deck everything works fine. You may need to do further research to find which number is bad.

 

[dmac]

I calculate your deck hight as 202.542.
Compression hight+ Rod length + half the stroke.
You will still need to add deck clearance to this.

Dave.

 

[abcmorgan]

No you are not nuts. There are some bad numbers somewhere. With an 8 inch deck everything works fine. You may need to do further research to find which number is bad.

Thanks Steve, I'm in awe of your V8 build by the way, amazing work!! I have made of couple of Jan Ridders models in Solidworks but I wanted to try doing something else to build up skills / knowledge on IC engines. Good to know I'm not barking up the wrong tree altogether.

I've tried to do a bit of reverse engineering from the following drawing and things come out close enough if I ignore the specs for Deck height but use everything else.

Thanks Dave, you replied as I was composing this! I printed out the drawing and used a compass to measure a known measurement and then used this to measure from crank to deck, came up with roughly 207mm which points to what you were saying when I allow for the innacuracy of my measurements using the printout. Now I'll have to track down a height for deck clearance and find out what it means!


If anybody out there has any other drawings/specs/references on this engine I'd appreciate it if you'd let me know.

 

[stevehuckss396]

American V8's have a deck clearance around .020 - .025. I imagine the pistons are held down a bit in the event a cleanup cut is needed. With a 8 inch deck the deck clearance would be .026.

 

[magrones]

to stevehuckss396

Dear Steve!

I am interested in the drawing about the cosworth dfv engine.
Can you get me a copy?
Magrones

 

[stevehuckss396]

to stevehuckss396

Dear Steve!

I am interested in the drawing about the cosworth dfv engine.
Can you get me a copy?
Magrones

I'm sorry Magrones but I am not the guy with the drawings. abcmorgan is the person who posted the pictures of the drawings.

 

[canadianhorsepower]

nice project , are these plans availlable to publicscratch.gif

 

[arborpress]

I have been working on a set of detailed and complete plans for quite a while. For an engine that has been used for so long and by so many people, it is amazingly difficult to get all the information necessary to build a model.
Here are some things that I have found or calculated:
-I don't really think deck clearance is much of an issue as this engine has a penthouse chamber shape. From some diagrams I have found, it looks as though the top of the piston (which is flat besides valve cutouts) comes right up to be flush with the deck.
-The dimensions in your drawing are the same as what I have for an early 70s DFV. Simply adding the dimensions of half the stroke, con rod length, and compression height gives a distance of 202.6031mm. I compared this theoretical deck height with some drawings and it actually looks spot on.
-be aware that some drawings are distorted because of folded of uneven pages being scanned.
-If you continue this, keep in mind that cylinder heads and the cam covers are identical left and right, so you don't need to make separate left and right molds.
-Again, if you get this far, the real thing uses Lucas MK1 mechanical fuel injection. It is actually pretty simple and you may easily be able to scale it down easily. Basically, a high pressure fuel pump driven by a cable drive off of one of the camshafts provides pressurized fuel to a metering unit, which is essentially a distributor, except for fuel. then from there it goes to the nozzles in each velocity stack. Couldn't be simpler.

 

[metalmad]

HI abcmorgan
Love your project, very cool indeed!
Are you going to cast it?
Pete