Home  
Site Partners: SpotterGuides Veloce Books  
Related Sites: Classic Cars Monthly Your Link Here  

Go Back   TenTenths Motorsport Forum > Historic Racing & Motorsport History > Motorsport History

Reply
 
Thread Tools Display Modes
Old 25 Apr 2010, 21:17 (Ref:2679618)   #26
rkshanahan
Rookie
 
Join Date: Jul 2003
Location:
San Diego, CA, USA
Posts: 79
rkshanahan should be qualifying in the top 10 on the grid
Martin,

The original cam for the SCA was the F1 profile. It has .402" lift and 324 deg. seat to seat. Like you, I was thinking I would end up using something more like 300 deg. seat to seat for the SCB, but I was waiting for the flow data to see if additional lift was going to be useful.

Since there is no data on the SCB (it appears Cosworth only built one) I am having to make up the specs as I go along. I am planning on using the 4.825" rods unless they don't leave me with enough room for the larger dish in the piston. The piston guy is supposed to get back to me next week about whether I have enough compression height. If not I will have to custom make some shorter rods.

I noticed that an earlier post to this thread noted that Keith Duckworth said the SCA needed too much ignition advance to be efficient. I am trying to figure out what I can do to the shape of the dish in the piston to make the chamber "faster". I am working with the piston guy on this, leaving large squish areas and such, but I don't know what else to do. Possibly this is why the "high swirl" intake ports were so important.

Regards,

Rob
rkshanahan is offline  
Quote
Old 26 Apr 2010, 00:53 (Ref:2679684)   #27
tony griffiths
Racer
 
Join Date: Jun 2003
United Kingdom
california
Posts: 134
tony griffiths should be qualifying in the top 10 on the grid
Cosworth SCA F2 Spec sheets :

Capacity 997cc Bore 81.0mm Stroke 48.35mm

Gross HP : 115bhp minimum @ 8,700rpm, rev limit 9,500

Cam ; F1 - 102 degree

Inlet valve size : 1.45"
Ex " " : 1.25"

Note pistons are two ring suggesting slipper type .....

Copies of sheet available and get any components made .....
tony griffiths is offline  
Quote
Old 26 Apr 2010, 10:09 (Ref:2679802)   #28
phoenix
Veteran
 
phoenix's Avatar
 
Join Date: Jul 2005
European Union
Posts: 1,981
phoenix should be qualifying in the top 5 on the gridphoenix should be qualifying in the top 5 on the grid
Quote:
Originally Posted by tony griffiths View Post
Cosworth SCA F2 Spec sheets :

Capacity 997cc Bore 81.0mm Stroke 48.35mm

Gross HP : 115bhp minimum @ 8,700rpm, rev limit 9,500

Cam ; F1 - 102 degree

Inlet valve size : 1.45"
Ex " " : 1.25"

Note pistons are two ring suggesting slipper type .....

Copies of sheet available and get any components made .....
Do you have a spec sheet for the SCC also? I found a reference on the web that these produced 135 BHP from 1099.6 cc (83.5 mm bore and 50.20 mm stroke) but with the same size inlet valve - so I'd like to find confirmation of that. Also Rob mentioned that some SCCs had 1.55" inlet valves.
phoenix is offline  
Quote
Old 26 Apr 2010, 10:16 (Ref:2679805)   #29
phoenix
Veteran
 
phoenix's Avatar
 
Join Date: Jul 2005
European Union
Posts: 1,981
phoenix should be qualifying in the top 5 on the gridphoenix should be qualifying in the top 5 on the grid
Rob

Are you planning to use and 83.5 mm bore for your SCB? If you are free to do so you could find a 6% improvement on torque output from the 1593.5cc that would result in (same capacity as the FVA I believe) and more bore clearance for your 1.6" inlet valve.
phoenix is offline  
Quote
Old 26 Apr 2010, 17:13 (Ref:2680022)   #30
Robyn Slater
Veteran
 
Robyn Slater's Avatar
 
Join Date: Nov 2005
England
Sudbury Suffolk
Posts: 515
Robyn Slater should be qualifying in the top 10 on the grid
Thanks for posting the photos Rob,
What is the purpose of the small dumbell shaped shaft that fits in the nose of the crank?

Pheonix, interesting you should mention the downdraught conversion as i've recently done this mod on my anglia engine.Also interested in the calcs to determine cam profile. Any suggestions where i can find info for further study?

Robyn
Robyn Slater is offline  
Quote
Old 26 Apr 2010, 19:19 (Ref:2680112)   #31
phoenix
Veteran
 
phoenix's Avatar
 
Join Date: Jul 2005
European Union
Posts: 1,981
phoenix should be qualifying in the top 5 on the gridphoenix should be qualifying in the top 5 on the grid
Quote:
Originally Posted by Robyn Slater View Post
Also interested in the calcs to determine cam profile. Any suggestions where i can find info for further study?

Robyn
Hi Robyn

I have my own and very crude method of evaluating the duration required, based on cylinder capacity and revs required, which I have devised myself. Nominal lift I determine from valve diameter and the calculated gas speed through the curtain area. These are both very, very crude and I would never spec my own cam as I am certain I haven't mastered the finer details of cam design - I would always talk to an expert and get their advice.

If you are seriously developing an engine and they know you are going to give it the dyno time and all the other effort involved, there are cam manufacturers who will do their best to arrive at the correct cam profile even if it takes a couple of attempts. If you want to know who I would suggest you talk to, drop me a PM.

Bye the way, I thought you were a twincam man?
phoenix is offline  
Quote
Old 26 Apr 2010, 20:27 (Ref:2680165)   #32
tony griffiths
Racer
 
Join Date: Jun 2003
United Kingdom
california
Posts: 134
tony griffiths should be qualifying in the top 10 on the grid
SCC specs

Capacity 1097cc Bore : 83.5mm Stroke : 1,970"

Gross HP : 130bhp minimum @ 8,500

Cams : F1

Inlet valve : 1.53"
Ex " : 1 .30

Slipper pistons

Lucas Opus ign !

Carbs 40 IDF

Rev limit 9,500

SCB -- no spec -- marked as development purposes only
tony griffiths is offline  
Quote
Old 28 Apr 2010, 06:15 (Ref:2680913)   #33
rkshanahan
Rookie
 
Join Date: Jul 2003
Location:
San Diego, CA, USA
Posts: 79
rkshanahan should be qualifying in the top 10 on the grid
Quote:
Originally Posted by phoenix View Post
Do you have a spec sheet for the SCC also? I found a reference on the web that these produced 135 BHP from 1099.6 cc (83.5 mm bore and 50.20 mm stroke) but with the same size inlet valve - so I'd like to find confirmation of that. Also Rob mentioned that some SCCs had 1.55" inlet valves.
Actually, it was the SCD 1500cc engine that was listed as having a 1.55" intake valve. I don't know if they ever built one or not.

Robyn, the small shaft in the nose of the crank is what drives the crank gear. The crank gear floats on the end of the crank on a bronze bushing and the two pins limit its rotational travel. I am assuming this was all done to damp out torsional vibration and prevent it from being transmitted to the cam drive gear train.
rkshanahan is offline  
Quote
Old 28 Apr 2010, 06:28 (Ref:2680919)   #34
rkshanahan
Rookie
 
Join Date: Jul 2003
Location:
San Diego, CA, USA
Posts: 79
rkshanahan should be qualifying in the top 10 on the grid
Quote:
Originally Posted by phoenix View Post
Rob

Are you planning to use and 83.5 mm bore for your SCB? If you are free to do so you could find a 6% improvement on torque output from the 1593.5cc that would result in (same capacity as the FVA I believe) and more bore clearance for your 1.6" inlet valve.
Martin,
I was originally planning on using an 83.5mm bore for the exact reasons you stated. I will have to make a decision here very quickly. I have both 81mm and 83.5mm blocks, so I could go either way.

Regards,

Rob
rkshanahan is offline  
Quote
Old 28 Apr 2010, 17:51 (Ref:2681270)   #35
tony griffiths
Racer
 
Join Date: Jun 2003
United Kingdom
california
Posts: 134
tony griffiths should be qualifying in the top 10 on the grid
Cosworth did not build a SCD and FVA was 1598cc
tony griffiths is offline  
Quote
Old 28 Apr 2010, 20:43 (Ref:2681351)   #36
Robyn Slater
Veteran
 
Robyn Slater's Avatar
 
Join Date: Nov 2005
England
Sudbury Suffolk
Posts: 515
Robyn Slater should be qualifying in the top 10 on the grid
Quote:
Robyn, the small shaft in the nose of the crank is what drives the crank gear. The crank gear floats on the end of the crank on a bronze bushing and the two pins limit its rotational travel. I am assuming this was all done to damp out torsional vibration and prevent it from being transmitted to the cam drive gear train.
I think i'm getting this now
The Quill (dumb bell) actually drives the gear and acts as a torsional damper,limited by the pins in the nose of the crank.
Sorry but i can now see thats exactly what you said.

When i read the Cosworth book a while back i remember it said the Duckworth used "Quills" to cure torsional vibration problems in the DFV engine.
Up till now i didn't understand what they meant but now i have a better understanding


Pheonix,Where did you get the impression that i'm a Twink man?
Robyn Slater is offline  
Quote
Old 29 Apr 2010, 06:15 (Ref:2681468)   #37
rkshanahan
Rookie
 
Join Date: Jul 2003
Location:
San Diego, CA, USA
Posts: 79
rkshanahan should be qualifying in the top 10 on the grid
Gentlemen,

Below is a shot of the SCA cam carrier, cam, tappet, and bearing inserts. Interesting that the cam carrier and caps are cast iron, I assume to provide a good bearing surface for the tappets. It appears that the cam bearing inserts are same as Twincam, but the tappets are different, actually a little larger in diameter. Too bad, as I had assumed I would be able to use off the shelf tappets. Now it looks like I will be spending some money with Arrow for custom tappets, as I only have one set of tappets between the four engines.

Tony, thanks for the info on the SCC engine, as I had not been able to find anything. How did you come accross all the Cosworth data sheets?

Regards,

Rob
Attached Thumbnails
DSCN0524.jpg  
rkshanahan is offline  
Quote
Old 29 Apr 2010, 15:35 (Ref:2681730)   #38
tony griffiths
Racer
 
Join Date: Jun 2003
United Kingdom
california
Posts: 134
tony griffiths should be qualifying in the top 10 on the grid
Rob,

Used to work for Cosworths in the late 70's and was given spec sheets on the majority of the engines !
tony griffiths is offline  
Quote
Old 2 May 2010, 17:09 (Ref:2683294)   #39
rkshanahan
Rookie
 
Join Date: Jul 2003
Location:
San Diego, CA, USA
Posts: 79
rkshanahan should be qualifying in the top 10 on the grid
Gentlemen,

Here are a few more photos of some things I find interesting about the SCA/C. The shot of the timing gears shows (I believe) an early and a late compound gear which mounts to the front of the cylinder head and actually drives the cam gear. The early one on the left has bolts holding the two gears together, but the later one on the right uses 4 spring pins. I am thinking that the spring pins might be able to give just a little bit and help with the torsional vibration damping in the cam drive geartrain. Or possibly it was just a cheaper, quicker way to join the gears. I have never rebuilt a DFV, but I am told that the torsional vibration damping in that engine is accomplished within the compound gear at the branch of the "Y" in the geartrain.

The third photo shows the Lucas Opus ignition box and distributor; there was also a normal looking ignition coil as part of the system. I have never seen this setup except on F2 cars from this period. I have run several F1 cars from that period and they seem to run a larger box that includes the ignition coil inside it.

Regards,

Rob
Attached Thumbnails
DSCN0526.jpg   DSCN0527.jpg  
rkshanahan is offline  
Quote
Old 3 Jul 2010, 23:42 (Ref:2721609)   #40
rkshanahan
Rookie
 
Join Date: Jul 2003
Location:
San Diego, CA, USA
Posts: 79
rkshanahan should be qualifying in the top 10 on the grid
chassis number and history of SCB powered cars

Since I have more than a passing interest in the SCB engine, I started looking into just how many were built. I found a post from Bob Ilich in Oz stating that three were built, including the one in his car. I looked into the F2 register for '67 and found two cars:

Brabham BT-16 F2-23-65 Driver Brian Redman Entrant David Bridges
Cooper T83 F3-1-66 Drivers David Darby/Brian Myers Entrants same

I then found a Palliser/SCB driven by Hugh Dibley in a Formula Libre race in '67, which makes 3 engines.

Bob Ilich took delivery of Brabham BT-21B-16 with an SCB, I assume in '68, and took it to Australia where it remains today, still with the SCB.

There is mention of another BT-21B with an SCB used by Louis Parsons in Formual Libre racing in '69-70.

I figure the engines from the BT-21s could have come from earlier cars, so there still might be only 3 engines.

Can anyone shed any additional light on this?

Regards, Rob
rkshanahan is offline  
Quote
Old 10 Jul 2010, 23:12 (Ref:2724596)   #41
edholly
Rookie
 
Join Date: Feb 2004
Australia
sydney
Posts: 63
edholly should be qualifying in the top 10 on the grid
Quote:
Originally Posted by rkshanahan View Post
Gentlemen,

Below is a shot of the SCA cam carrier, cam, tappet, and bearing inserts. Interesting that the cam carrier and caps are cast iron, I assume to provide a good bearing surface for the tappets. It appears that the cam bearing inserts are same as Twincam, but the tappets are different, actually a little larger in diameter. Too bad, as I had assumed I would be able to use off the shelf tappets. Now it looks like I will be spending some money with Arrow for custom tappets, as I only have one set of tappets between the four engines.

Tony, thanks for the info on the SCC engine, as I had not been able to find anything. How did you come accross all the Cosworth data sheets?

Regards,

Rob
The cam carrier design looks to me very much like it could have been copied from a Coventry Climax FWA/FWE/FWB, maybe the buckets are the same size if that is the case. Climax buckets are 1.398 inches as best I can measure with them in the head. Not sure of the length or internal step height, but a check with a Climax stockist - Dave Bean, Bill Hutton etc would soon tell you.

The SCA SCB are to me a real jewel of a motor ...

Photo is of a rare 5 bearing version of the Climax carrier in an FWA from a Lotus Eleven that has been apart now for over 30 years.

Ed
Attached Thumbnails
Climax 5 brg cam 007.jpg  

Last edited by edholly; 10 Jul 2010 at 23:25. Reason: add photo
edholly is offline  
Quote
Old 17 Sep 2010, 05:02 (Ref:2760704)   #42
rkshanahan
Rookie
 
Join Date: Jul 2003
Location:
San Diego, CA, USA
Posts: 79
rkshanahan should be qualifying in the top 10 on the grid
Update and new flow data

Gentlemen,

It has been a while since I updated this thread, but progress has been slower than I hoped. Since my last post I have gotten my pistons made, sleeved my block down to 81mm, made a crankshaft, recieved my new cam blanks and new cam followers, and finished up my flow work on the cylinder head. I have now selected a cam profile based on the flow data, so the cam grinder can get to work finishing up the camshaft. I needed to replace some missing or damaged timing gears, and those gears are now cut but need heat treating to be complete. I am hoping I can start on assembling the engine as soon as the gears are finished.

The flow data on the cylinder head was disappointing. The stock intake port flowed 150 cfm @ 28" vac. which was less than I was expecting. We were able to get the one "large valve" head I have up to 185 cfm @ 28", but I am told that even a mildly ported Twincam head would be over 200 cfm. The low lift flow was really down compared to a Twincam. The good news is that the flow numbers were the same with the intake manifolds and carbs bolted on, so at least I don't have any restriction there. I was able to pick up 7 cfm by stepping up the venturi size in the carbs by 2 mm.

Please let me know if there are parts you would like photos of or additional detail I can provide. I will be busy the next couple of weeks, but after that I plan to get the first engine together and on the dyno pretty quickly.

Rob
rkshanahan is offline  
Quote
Old 7 Jan 2011, 06:02 (Ref:2812265)   #43
rkshanahan
Rookie
 
Join Date: Jul 2003
Location:
San Diego, CA, USA
Posts: 79
rkshanahan should be qualifying in the top 10 on the grid
SCC engine update

I am assembling the one SCC 1100cc engine I got in my parts package. The SCB project is on hold until I can sort out some gear backlash issues. The head has been decked in the past, which of course means the backlash between the gear attached to the head and the gear attached to the block is now zero. I am getting a thicker head gasket made to take care of the issue.

I only just recieved the folder with the paperwork that came with my engines. It included a copy of the Cosworth "manual" for the SCC. It is 6 typewritten pages, and includes the specs and assmebly instructions. There was also a drawing of the crankshaft snout and crank gear included, which was really helpful, and a drawing of the standard SCC pistons. It was pretty interesting pressing the crankshaft gear and its drive quill into the nose of the crankshaft, but I now have the hang of it. Requires some pretty precise grinding of the quill in order to get the press fit just right.

I have also made some pretty significant headway on gathering the parts to make one of the engines fuel injected. I have managed to buy an original SCA Lucas metering unit mount, which was going to be a real pain to fabricate. I also now have a proper 6mm metering unit, a mechanical pump, injectors, and most of an intake manifold with slide throttles.

I have had a couple of people ask me how they can build up an SCA out of bits. I think you could buy or make most of it, but the cylinder head would be the problem. You can't just make one from scratch, and I don't know where you can buy any spare.

Regards,

Rob
rkshanahan is offline  
Quote
Old 5 May 2015, 08:36 (Ref:3534247)   #44
Steve72
Rookie
 
Join Date: Mar 2015
France
Near Le Mans, France
Posts: 2
Steve72 should be qualifying in the top 10 on the grid
Hi all, <br />
I have found your forum fascinating and very informative, helping me with something which may be of interest to someone here.<br />
I have found an SCA engine, totally complete and assembled with F2 exhaust and engine mounts and pumps alternator etc. with Lucas slide throttle injection, sadly static in a barn for the last 35 years, athough covered with blankets. Any interest?? The owner wishes to sell, it is located near Le Mans France.
Steve72 is offline  
Quote
Old 5 May 2015, 08:42 (Ref:3534248)   #45
Steve72
Rookie
 
Join Date: Mar 2015
France
Near Le Mans, France
Posts: 2
Steve72 should be qualifying in the top 10 on the grid
I forgot to say, you can reply here, or email me on steve.peel@hotmail.co.uk Thanks, Steve.
Steve72 is offline  
Quote
Old 12 Dec 2017, 06:18 (Ref:3786475)   #46
rkshanahan
Rookie
 
Join Date: Jul 2003
Location:
San Diego, CA, USA
Posts: 79
rkshanahan should be qualifying in the top 10 on the grid
SCA update

It has been years since I last posted about my SCA engine projects, so I thought it was time for an update in case anyone was interested.

Since my last post I have completed 3 of the 5 engines I bought, plus bought another one. I have completed one carbureted SCA and two injected SCAs. The carbureted engine and one of the injected engines went with my old Lola T60 which I sold to Robs Lamplough in the UK about 5 years ago. The remaining injected SCA is going in my current Lola T60 which I plan to sort out and then ship to the UK this winter. I still have the one SCC engine and the partially assembled SCB, plus the injected SCA I bought recently. The problem with the SCC and SCB is that I realized they are much less desirable than an SCA. The only real market for these engines is in Europe, particularly the UK, and for that they have to be 1000 cc. I was going to build the SCB for use here in the US where it would be legal (it would have to run against TwinCam-powered cars), but I have never kept a car here in the US long enough to make an SCB of any use. I had inquiries from Australia for both the SCC and SCB, but both of those deals fizzled out, so here they sit.

The Lucas injection really made the engines come alive. The two injected engines I built both put out a little under 140 hp @9500 rpm on the engine dyno. This is slightly less than Cosworth claimed for their ultimate 1966 engine (142 bhp @ 11,200), but I have used relatively mild cams that give a very broad torque band and the result has been a very drivable engine. I have attached a photo of the first injected SCA I built plus the dyno results for it. Note that there is not a lot of torque, but the curve is almost flat from 6000 rpm to 9500 rpm, which is a very useful rev range.

Regards,

Rob
Attached Thumbnails
Injected SCA.JPG  
Attached Files
File Type: doc SCA dyno chart.doc (49.0 KB, 25 views)
rkshanahan is offline  
Quote
Old 24 Dec 2017, 04:59 (Ref:3788941)   #47
Bryan Miller
Veteran
 
Join Date: Apr 2003
Location:
Kiama , N.S.W. Australia
Posts: 1,379
Bryan Miller should be qualifying in the top 10 on the grid
Rick,

Congratulatios on these projects.
Bryan Miller is offline  
Quote
Old 29 Jan 2018, 13:34 (Ref:3796601)   #48
AnnecyRacer
Rookie
 
Join Date: Jan 2018
Posts: 5
AnnecyRacer should be qualifying in the top 10 on the grid
Any more news on the SCA engines please. Not much written about these jewels and as such am interested in reading whatever's out there. Have an ambition to put an engine together as I slowly, very slowly collect parts. Managed to procure three Cosworth con rods with used pistons along with four unused Holbay rods and pistons recently. Have a block too but that's about it. A long way to go....
Are there any eng. drawings available, might need to make or have parts made such as gears etc.
AnnecyRacer is offline  
Quote
Old 13 Feb 2018, 18:16 (Ref:3801049)   #49
rkshanahan
Rookie
 
Join Date: Jul 2003
Location:
San Diego, CA, USA
Posts: 79
rkshanahan should be qualifying in the top 10 on the grid
SCA parts

Hi AnnecyRacer,

The best source for parts is going to be Geoff Richardson Engineering. They make all the parts for the SCA including the cylinder head casting. Modatek in the UK is the official parts supplier for historic Cosworth engines, and many of the parts are available through them. As to drawings, I have seen copies of the original drawings for a couple of the parts on the internet, but only for a couple of random "bits and bobs".

As to used parts, a friend of mine bought a bare SCA head casting off of Ebay a couple of years ago, but something like that would be a really rare occurrence. Check out Len Selby's historic racing parts website, where I have bought some good used parts. Be careful about identifying the parts, as Len can't be an expert on everything and he therefore has to rely on the sellers descriptions. Len provides good photos of the parts so you can look them over carefully before you buy.

You can also check the 1-litre Formula Two Facebook page. They have a parts for sale section, and I have some crankshafts, flywheels, etc. advertised there.

Good luck!

Rob
rkshanahan is offline  
Quote
Old 26 Feb 2018, 13:46 (Ref:3804043)   #50
AnnecyRacer
Rookie
 
Join Date: Jan 2018
Posts: 5
AnnecyRacer should be qualifying in the top 10 on the grid
Hi, thanks for taking the time to reply. I'll take your advice and will look up the F2 website link. Thanks.
AnnecyRacer is offline  
Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Cosworth Vega 2L [Circa 1970]F2 engines Peter Nightingale Motorsport History 17 13 Dec 2005 02:35
Minardi to run Cosworth V10 engines in 2006 Ryo28 Formula One 29 10 May 2005 18:31
Minardi secure Cosworth engines for 2005 Stephen Green Formula One 8 31 Aug 2004 19:07
The Ford Cosworth customer - The Grim Reaper of F1 engines? Yoong Montoya Formula One 8 28 Nov 2002 11:42


All times are GMT. The time now is 17:42.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Original Website Copyright © 1998-2003 Craig Antil. All Rights Reserved.
Ten-Tenths Motorsport Forums Copyright © 2004-2021 Royalridge Computing. All Rights Reserved.
Ten-Tenths Motorsport Forums Copyright © 2021-2022 Grant MacDonald. All Rights Reserved.