Reversed-head 16v conversion 2 liter startup

Competition engines and 'live' projects only. Good photos to illustrate your post are expected.
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cstorry
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Reversed-head 16v conversion 2 liter startup

Post by cstorry »

Guy

I read with interest your post in the workshop about Carlos' engine start-up (and of course watched the video).

I am very interested in the effort to do this. I have heard rumors in the past of people attempting this but had not heard of any successes.

(In case it was a test I did find a reference to this exercise on page 201 of your new book - were there other references or details I missed ?)

I have taken to heart (and agree with) your recent comments about the cost of an original Abarth 16V head so this seems like what Carlos has achieved may be a viable alternative.

I am interested in a similar exercise as applied to say an 037 replica which would eventually have to work with the volumetrico blower (which I can afford).

Can you or Carlos provide at least a high level discussion of what is involved in mating the later 16V heads to the early 2 Liter blocks in a Gp4-like flow direction ?

Thanks

Chuck
Guy Croft
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Re: Reversed-head 16v conversion 2 liter startup

Post by Guy Croft »

This is no different in general terms to any of the 16v conversions in my new book except that the head is turned thru 180 deg.

It begins with offering up a gasket from the early block and welding-up coolant, oil drains where necessary for the reversal - then the cam setup has to be examined with the cam nose at the 'wrong end'. I was part of the post-weld machining and fettling on this one and I gasflowed it. I supplied contemporary 16v atmo cams and the actual cam setup stuff - Carlos did himself.

Though I take no credit for getting on and actually doing it - Carlos was the first I know of - having seen it I would not rate it as an overly difficult thing to do.

Naturally the bottom-end was race rods and pistons.

All credit (really!) to Carlos. He was the 'dream' client to work for, although he doesn't speak much English, with the help of his English-speaking friend Cesar he listened to every word I said and followed my advice to the letter, including sump, header, oil and cooling system, Omex mappable ignition, jets, clutch and every single part, accessory and op - THE LOT. With so many ignorant smartarses in the world today (and I can think of one notorious example with an Italian name in Australia) arguing with GC methods this is an increasingly rare pleasure.

GC
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general view of weld alterations.jpg
general view of weld alterations.jpg (449.68 KiB) Viewed 15849 times
some of the weld alterations.jpg
some of the weld alterations.jpg (112.86 KiB) Viewed 15849 times
typical weld.jpg
typical weld.jpg (111.21 KiB) Viewed 15849 times
offering up gasket post-weld.jpg
offering up gasket post-weld.jpg (109.24 KiB) Viewed 15849 times
post-weld fettling at GCRE.jpg
post-weld fettling at GCRE.jpg (109.88 KiB) Viewed 15849 times
drilling out revised coolant holes.jpg
drilling out revised coolant holes.jpg (118.01 KiB) Viewed 15849 times
gasflowing the head.jpg
gasflowing the head.jpg (115.36 KiB) Viewed 15849 times
relief for high lift steel billet atmo GC cams.jpg
relief for high lift steel billet atmo GC cams.jpg (114.26 KiB) Viewed 15849 times
doing the seats.jpg
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might look weird but I guarantee it all 'seals up' where it should.
might look weird but I guarantee it all 'seals up' where it should.
finished head ready for Carlos to build.jpg (115.28 KiB) Viewed 15849 times
cstorry
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Re: Reversed-head 16v conversion 2 liter startup

Post by cstorry »

Thank-you Guy

I had been told (and confirmed from inspection but without measurements) that the head was more or less symmetrical -seems it is so or can be made so with minor welding/drilling.

What intrigued me about what Carlos did was the ability to swap cams end for end. You show one picture with some modification of the cam area but I assume by your annotation that the relief operation is due to cam profile and not the end for end swap ?

Do you know if stock cams would fit or is a completely custom cam required ; length, nose extension, etc ?

Thanks
Chuck

P.S. I'll have to go out to the shop to check on the parts I have before I can ask more intelligent questions about other potential head issues such as external machining for clearance or mounting brackets or holes on the outside end faces. (-26 C here today so I will wait a few days : )
WhizzMan
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Re: Reversed-head 16v conversion 2 liter startup

Post by WhizzMan »

I know that the Alfa Romeo 155 BTCC cars used an 8V bottom end with a reversed 16V head. This is the "Lampredi" engine as used in Lancia Delta and such. I'm assuming they did something similar, but they had the advantage of having access to raw castings.
Guy Croft
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Re: Reversed-head 16v conversion 2 liter startup

Post by Guy Croft »

I don't know how Carlos tackled the cam issue!

The cams I supplied were of conventional OE design though not profile,

G
tricky
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Re: Reversed-head 16v conversion 2 liter startup

Post by tricky »

I would imagine that relocating the cams thrust groves would pose the biggest problem.
Guy Croft
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Re: Reversed-head 16v conversion 2 liter startup

Post by Guy Croft »

..........well he certainly overcame that!

And he did it on his own too.

G
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CMB 16v head front view.JPG
CMB 16v head front view.JPG (171.32 KiB) Viewed 15671 times
CMB 16v head rear view.JPG
CMB 16v head rear view.JPG (174.1 KiB) Viewed 15671 times
CMB 16v Seat.JPG
CMB 16v Seat.JPG (153.94 KiB) Viewed 15671 times
CMB 16v Seat engine bay.JPG
CMB 16v Seat engine bay.JPG (173.14 KiB) Viewed 15671 times
franco1600
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Re: Reversed-head 16v conversion 2 liter startup

Post by franco1600 »

sorry if i ask somthing obvious, but... wich is the reason of "inverting" the head in this case?

does he use the exhaust side of the head as inake???

or he is inverting because these head were from a transverse engine??

in argentina some of these things were done to improve the amount of air that comes into the engine, placing the intake side in the front of the car (transverse engine)
Guy Croft
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Re: Reversed-head 16v conversion 2 liter startup

Post by Guy Croft »

I understand from detailed conversations with Carlos in the beginning that if it 'looked like' a Gp4 setup, with inlet and ex on the same side as the Gp4 Seat rally cars it would be considered 'legal' for historic rally in Spain whereas the normal setup of the late generation head would not be acceptable. I did ask if him if he was quite sure it would be OK because Gp4 stuff is so costly to get hold of..

Whatever we make of this ruling by the sport controlling body, I am sure it is true otherwise he would never have undertaken such a difficult project (I mean compared with a simple 16v conversion). I doubt if any rally authority in the UK would ever agree to it unfortunately.

That is how I understand it anyway.

GC
jonboyd
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Re: Reversed-head 16v conversion 2 liter startup

Post by jonboyd »

Any thoughts on the plausibility of leaving the head direction alone, but swaping cams and using the exhaust side as the intake side.

Obvisouly would take some manifold 'plumbing'

Was thinking of a 'Franken-Fiat' 124 spider with the 16v head, fuel injected, turbo with intake on the left side, exhaust on the right.

Obviously the valve sizes would be reversed. Does that make it a non-starter?

Jon
WhizzMan
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Re: Reversed-head 16v conversion 2 liter startup

Post by WhizzMan »

Cooling, valve sizes, shape and size of the channels would all be "wrong" if you merely reverse the flow and use exhaust for inlet. You may be able to get a running engine that won't overheat if you build it, but it'd hardly be optimal. Optimizing the head, if the castings would permit it at all, will probably be much more work than just reversing it.

Another reason for reversing the flow is in transverse engine mounting setups, like the 155 BTCC. The original factory 155 has the exhaust on the front of the car and the inlet on the rear. If you want to move the engine as low and as much to the rear of the engine compartment as possible, you'd rather have those inverted. That way, you can slant the head back and have the exhaust point downwards past the slam panel and away under the car. That would give you a lower center of gravity and the entire upper part of the engine compartment free to be used as an air box.
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