Hello all,
My 1975 Strada was sold with a few crates of spare parts. Included was a pair of NOS cylinder heads still wrapped in very old brown paper and tied up with twine. Well I recently unwrapped one to check it out and was surprised at what I found.
The heads are new and perfect except that they are what I would call blank castings. Completely undrilled and without any internal threads. No spark plug threads. No exhaust nut threads. All the holes for studs are all undrilled.
Can anyone explain what I have ? Do these have any value ? Anyone interested ?
Cylinder head "blanks"
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Blue Morini USA
- Posts: 12
- Joined: 31 Oct 2016 14:44
- Location: East Norriton, USA
Re: Cylinder head "blanks"
I suppose they could be locally produced items, but I'm pretty sure the originals are die castings. There are specialised sand casting firms in the UK who will replicate castings from originals so I'm sure there would be in the USA. Does the quality of the casting look the same as the ones on your bike otherwise , i.e. fineness of grain?
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George 350
- Posts: 452
- Joined: 16 Jun 2007 09:43
- Location: Northampton
Re: Cylinder head "blanks"
Hi,
I'm 100% positive that all the main engine castings were sand castings. The finish on them and the porosity in the castings when you bead blast them would not be there if die cast. Compare the finish on the heads and die cast rocker covers to see the difference. Apart from the aforesaid rocker covers and ignition pick up covers (simple castings) - their volume of production would never have justified the cost for the tooling to do the more complex engine parts as die cast.
Whether they are the original castings as used by the factory or 'aftermarket copies' would be quite difficult to say, but it seems an odd thing to copy when 'as new' heads are easily available second hand.
As to their value, they are either priceless for the special motor builder, have an object d'art value or just scrap value, depending upon your viewpoint.
To machine them into functioning heads, most of the machining is straightforward, with the only awkward machining being the plug, plus the inlet and exhaust ports, especially without having any drawings. Valve seats and guides are available if you know where to look.
Hope that this helps,
George.
I'm 100% positive that all the main engine castings were sand castings. The finish on them and the porosity in the castings when you bead blast them would not be there if die cast. Compare the finish on the heads and die cast rocker covers to see the difference. Apart from the aforesaid rocker covers and ignition pick up covers (simple castings) - their volume of production would never have justified the cost for the tooling to do the more complex engine parts as die cast.
Whether they are the original castings as used by the factory or 'aftermarket copies' would be quite difficult to say, but it seems an odd thing to copy when 'as new' heads are easily available second hand.
As to their value, they are either priceless for the special motor builder, have an object d'art value or just scrap value, depending upon your viewpoint.
To machine them into functioning heads, most of the machining is straightforward, with the only awkward machining being the plug, plus the inlet and exhaust ports, especially without having any drawings. Valve seats and guides are available if you know where to look.
Hope that this helps,
George.
George
350 sport 1978, 350 Strada 1978
650 Norton 1967, 650 Kawasaki 1977 and 650 Enfield 2019
350 sport 1978, 350 Strada 1978
650 Norton 1967, 650 Kawasaki 1977 and 650 Enfield 2019
Re: Cylinder head "blanks"
OK, looking at one I have lying about missing a valve guide I see what you mean. I knew they wouldn't be pressure die cast but thought they might have been gravity die cast, seeing as the modular design meant they made a fair run of 350/250 heads.