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Chris Bucknell
Australia
107 Posts |
 Posted - 31/03/2010 : 09:28:07
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OK group. Was doing some research into car's history and thought of this question for everyone. I certainly know Bob M will love it!
What cars are known to have Bronze cylinder heads (4 and 6 cylinder)?
What cylinder heads survive today?
Regards,
Chris |
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PeterL
United Kingdom
1722 Posts |
Posted - 31/03/2010 : 11:51:12
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Chris
Please remember me to your parents, I visited them in 1986 and my daughter (5)fell in your swimming pool! I also saw the R.
Alas no bronze heads here.
Cheers
P |
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David Allison
United Kingdom
665 Posts |
Posted - 31/03/2010 : 14:02:59
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Chris
Have to check with "the old man" but I think these heads were quite rare!
Robin Jackson had a theory (alas since proved wide of the mark) that bronze would be superior in every respect to iron for cylinder head manufacture.
In fact it was found that although easier to cast than iron and with a lower scrap rate - bronze proved very expensive and also rather heavier than the iron head.
Also the superior ability of the bronze to carry heat away from the combustion chambers and valve heads was supeseded in later years by superior materials for valves.
In the 1970's my father among many others started using 214-N - these do not overheat as readily and dropped or burned valves have become a thing of rarity ever since.
As far as I aware there was only one 6 cylinder head - this was made for the Horton K3 and the engine subsequently fitted to EX 135 for the 200 mph record attempts.
This is probably the most highly supercharged pre-war MG engine and in 1100 cc form achieved a terminal speed of over 200 mph on the Jabbeke highway in Belgium (I think those facts are correct) note to self to read Maintaining the Breed again!
Jackson also made a head for the Evans C type sprint car.
This heavily modified car was fitted with an R type engine (amongst other mods) which had a bronze head for a time - although Wilkie Wilkinson removed the bronze head and fitted an iron one (probably because it was too heavy).
The other head was I think fitted to EX 127 and then EX 154 this is I think the engine that you have in your P type special?
I think that there may have been a J head made for the Horton C type as well?
But other more learned souls than I would have to add their 4 penny worth.
Hope this helps - might also be a load of tosh though!
Regards David |
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Bob Stringfield
United Kingdom
854 Posts |
Posted - 31/03/2010 : 21:09:10
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There may well be quite a few heads which look as if made from bronze but which are examples of the copper-plated heads done by V. W. Derrington in the 'thirties. ( see Autocar, 27/11/36 )
PA 0603 has one of these and its now toned appearance often fools onlookers into thinking that it is bronze and thus very special.
All the desired appearance plus the claimed 33% better acceleration, 12 1/2 % more speed and a 30% improvement on hill-climbing, all for £1-5-0. Good value, in the absence of Trading Standards. |
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Chris Bucknell
Australia
107 Posts |
Posted - 31/03/2010 : 22:42:37
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OK. So enough already with the disparaging remarks about the weight of the bronze head. Next time I have ours off I am going to weight it and we will all see if it is a significant difference or not.
So next piece of info is that in Motor Sport July 1938 edition page 252 there is the following "Odd Spots: J. H. T. Smith's M.G. has a bronze cylinder-head and a Marshall supercharger. The engine is tuned by Bellevue Garage and the car weighs 12 3/4 cwt."
So what car is this? |
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ht1962
Netherlands
114 Posts |
Posted - 31/03/2010 : 23:06:24
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I believe K3015/2 is the right answer to this one.
Regards
Halbe Tjepkema |
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Peter Green
United Kingdom
1682 Posts |
Posted - 01/04/2010 : 00:02:37
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Chris,
I think I am correct in saying that neither K3015/2 nor the KN in Sweden masquerading as JHT Smith's single seat race car have a bronze cylinder heads now.
Peter. |
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DickMorbey
United Kingdom
3677 Posts |
Posted - 01/04/2010 : 10:01:24
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I recall reading somewhere that the late Henry Moore tried to cast a small batch of these but was unable to get them to conform with the required dimensions and also experienced particular difficulty with cavitation.
Regards
Dick Morbey, PA/B 0743 |
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Colin Butchers
United Kingdom
1487 Posts |
Posted - 01/04/2010 : 11:13:41
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When he was super tuning QA0256 for Bill Humphreys in 1936/7, Robin Jackson was experiencing continual problems with the original cast iron heads which kept cracking so he approached Cecil Kimber and managed to persuade M.G. to cast a batch of Q type heads in Baronia Bronze. I read somewhere how many were made - I think it was at least 6. Jackson said that these completely cured the problem of head cracking and enabled them to run a much leaner mixture than previously. When Brian Finglass bought the kit of parts to make up QA0251 from Bill Humphreys after the war, the kit included two bronze heads but I do not know what happened to them.
I do know that Harvey-Noble's single seater QA0258 ran with a bronze head for a while, including when he set up the Class H Brooklands Outer Circuit Record, but this head was removed in 1938 and they reverted to a cast iron head. I don't know why this was, and it is one of many questions that I wish I had asked Harvey-Noble when I met him !
Colin B. |
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John Reid
United Kingdom
704 Posts |
Posted - 01/04/2010 : 11:21:47
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Dick,
My understanding was that it was Barbara Hepworth...!
John R |
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Gerhard Maier
Germany
873 Posts |
Posted - 01/04/2010 : 14:18:17
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Colin,
perhaps you read something about the quantities of bronce heads in the article of "Motor Sport" below.
I remember the widow of Bobby Kohlrausch telling me, that Bobby had 10 bronce heads cast in Germany for the Magic Midget, until the machining company was satisfied in finishing one of them without big problems with cavitation in the casting. She said the whole "story" cost us a fortune !
Gerhard
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Chris Bucknell
Australia
107 Posts |
Posted - 02/04/2010 : 01:09:12
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Wow! This turned out much more interesting than I could have expected.
Bob S. What else can you tell us about the plating to make heads look like bronze? Was this purely a cosmetic device OR did they seriously claim performance benefits?
Peter G. Can you tell us more about JHT Smith's single seat race car. What chassis, engine, gearbox configuration did it run? What do you know about what happened to it?
Does anyone know what Baronia Bronze is, composition wise?
So in summary we have sixteen 4 cylinder heads, seven 6 cylinder heads, 1 Bobbie Kohlrush head. For this we have the following original cars identified:
HT Smith's single seater
QA0256 - Bill Humphreys
K30015/2 ??
EX135
Again in Motorsport January 1938, Page 13, tells us Esplen's White R-Type (RA0256) now in Beer collection?? Was fitted with a bronze head. What is the status of the Beer collection?
I also believe but haven't found the reference yet that RA0255 (Evan's R-Type that went to South Africa) was fitted with bronze head BUT the head is lost.
EX127/EX154 with Kohlrush head
So out of all basically none of the factory ones have been located so far by this thread but the Kohlrush head is with Bucknell collection. Does EX135 head reside in Museum? Any others known today?
Easter greetings to all.
Chris
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Bob Stringfield
United Kingdom
854 Posts |
Posted - 02/04/2010 : 11:05:30
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I do not have a scanner or much ability with image transfer so the Derrington details, from the page reference given, are in 'longhand'.
Presumably they were a response to the 'thirties view that a bronze head was a great advantage; certainly, in my field of expertise, makers such as Rudge, Sunbeam, Norton et al experimented with bronze and composite bi-metal heads for their competition machines.
'Copperised Cylinder Heads.
Existing cast-iron heads can be copperised, giving truly remarkable results. Maximum speeds have been increased by 12 1/2 %, hill-climbing by 30%, and acceleration by 33 1/2 %.
From 25/- per head. Valves 2/- each
Proof Positive 3/5/36.
" The copper plating is a decided improvement, not only for smoothness and acceleration but also in petrol consumption". L.J.K.'
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Peter Green
United Kingdom
1682 Posts |
Posted - 02/04/2010 : 16:45:14
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Chris,
I will write to you 'off line' with the information about JHT Smith's single seat race car.
Peter. |
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McEvoy
United Kingdom
252 Posts |
Posted - 03/04/2010 : 13:44:20
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You are right Chris I am interested in this topic but at the moment enjoying a break on the Danube cruise and will refer to my notes next week on my return home. I can tell you from my "old" memory that R 0253 now in NZ had a copper plated twin cam head when I took it to the London docks prior to shipping and a McEvoy twin cam head was cast in bronze this of course being much heavier than the already much heavier cast iron head than the single OHC one which together with the heavy high mounted steering box would have exasperated the R leaning problems!
Bob M |
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Colin Butchers
United Kingdom
1487 Posts |
Posted - 04/04/2010 : 21:58:55
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Thank you for your comment Gerhard. I hadn't seen the article which you quote, but I now recall that the information I came across some time ago was the same. I believe that I am right in saying that the Bobby Kohlrausch bronze heads were cast by the firm of Robert Kramer - possibly of Cologne. I wonder whether more than one head was made - possibly at least two, one for EX127 and another for EX154.
Best wishes,
Colin B. |
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