12 replies to this topic

[x300]

A friend of mine has dug out an old cam cover from his automobilia collection and showed the following picture of it to a bunch of us, Japanese car enthusiasts, on a bulletin board in Japan.



We are almost settled on its identity being a cam cover from a BRM P56 engine on the account of its visual similarity to the following picture:

http://en.wikipedia....e_Donington.jpg

However, there is one remaining problem. The cam cover measures about 450mm long, and the fixing stud holes are spaced 88mm apart length-wise for the middle 4 pairs. (The end 2 pairs have different spacings to the middle four as you can see on the pic.)

I believe the 88mm spacings for the middle 4 pairs should directly translate to the engine's bore pitch, but the bore of a P56 should be 68.5mm. If the engine had 88mm bore spacings and 68.5mm bore, there were whopping 19.5mm (over 3/4 inch!) spaces separating its cylinder walls. It seems to me these spacings are excessive even for dry-liner - thick wall - coolant passage - thick wall - dry-liner combination.

Could someone properly identify the cam cover?
Or, is there a reasonable explanation behind this seemingly odd design for space efficiency?

I have seen a small picture of a P56 flat plane crankshaft (is it on display at Donington?), which did not seem that unusual in terms of main bearing width, or crank web thickness, to give me a clue.

Also, I was more inclined toward the cover being from a P75(H16, 69.85mm bore), but was shot down because all the H16 pictures we have seen show a riveted BRM plaque, instead of a cast-in BRM logo, on the covers.

I would appreciate any help you could provide.
Is there any book published on Aubrey Woods' works?

YI

Edited by x300, 26 February 2010 - 16:32.

[Pedro 917]

Looks exactly like the cam cover on Richard Attwood's BRM P261 :

[x300]

Thank you very much for the lovely picture.

You didn't measure the length of the valve cover, or did you?

[hansfohr]

A much closer look on the P56's cover cam......

[x300]

Thanks a lot.

A better resolution sometimes goes a long way. I'd appreciate good pictures of P60(1.9-2.1L V8), P71(1L F2), or the lower cylinder banks of the P75 H16 as well.
I suspect these all have similar size cylinderheads that there's a possibility that some of them might have interchangeable cam cover dimensions.

[hansfohr]

The H16 P75 engine in the back of a BRM P115




I presume this is the 2L P60 engine (fitted in a BRM P261)

Edited by hansfohr, 27 February 2010 - 09:01.

[Alan Cox]

A fabulous period photo from Norman Hayes' 1960s photo thread, of Innes Ireland in 2615
http://forums.autosp...w...01457&st=80
Copyright Norman Hayes

[x300]

I presume this is the 2L P60 engine (fitted in a BRM P261)

Thanks. That picture is the one on
http://en.wikipedia.org/wiki/BRM_P261
so, it is supposed to be an 1.5L P56.

BUT, if P60 shared the same external head dimensions with P56, who knows it may well have 2L (or, 2.1L) internals smile.gif

[Macca]

Here are 3 shots of the F2 1000cc engine in a Lotus 35:



Paul M

[x300]

A fabulous period photo from Norman Hayes' 1960s photo thread, of Innes Ireland in 2615

Thank you. This really is a fabulous photo, as it clearly shows the lower side hole in the rear to accommodate the early P54's bottom exhaust.
As I understand it, these holes on the side were patched up later when the newer top exhaust P54 (shown in the photo) became available, so the photo must have been taken after the Italian GP in 1964 when the top exhaust became available, and not much later in the year.

[Macca]

That picture was taken in late 1966 when the car was owned by Bernard White, entered as Team Chamaco-Collect.

Only two cars were built for side-exhausts with the slot and then fitted with centre-exhaust engines, 2614 and 2615. 2613 never had a centre-Exhaust engine, and 2626 and 2617 were built without the 'letter-box' slot and had centre-exhaust engines for their whole lives.

2614 had patches over the slots in later life, and is now at Donington:

Paul M

[x300]

Here are 3 shots of the F2 1000cc engine in a Lotus 35:

Paul M

Thank you very very much!
The third picture shows the cam cover to be exactly like the one in Tokyo.
As the 1L F2 P71 engine is a half of 2L P60 V8, head dimensions are supposed to be the same.

If P56, P60 and P71 (and possibly P75 H16) all shared the same head external dimensions, this may explain the wide gap between P56 cylinders I wondered about. The bore is the smallest on P56 (68.5mm) and the largest on P60(71.7mm for the 1.9L, to 74.63mm for the 2.1L) and P71(71.8mm) among the four engines in question, with the H16 (69.85mm) falling in between.
Assuming all four engines shared the same 88mm bore pitch, naturally P56 would have the widest gap.

Obviously Paul M's third photo does not prove that the cam cover dimensions are the same, but I'd go crazy if I am building different engines with different size cam covers that look the same. So I would think altering the shape or number of cast fins would be a logical engineering practice if there is a difference in size, and now I strongly suspect that all four engines, or at least three excluding the H16, would take the cam cover in question interchangeably.

[x300]

That picture was taken in late 1966 when the car was owned by Bernard White, entered as Team Chamaco-Collect.

Only two cars were built for side-exhausts with the slot and then fitted with centre-exhaust engines, 2614 and 2615. 2613 never had a centre-Exhaust engine, and 2626 and 2617 were built without the 'letter-box' slot and had centre-exhaust engines for their whole lives.

Paul M

Thank you. Thank you. You are my hero.