The Technical Questions Thread

[henk4]

thanks, it does explain the three exhaust, but but the exhaust valves in this sequence, makes it even more strange to use three carbs. The way you showed it would suggest a two carb setup....

[jediali]

Originally Posted by henk4

thanks, it does explain the three exhaust, but but the exhaust valves in this sequence, makes it even more strange to use three carbs. The way you showed it would suggest a two carb setup....

This would allow a 3 carb setup but while the outer 2 carbs will serve 2 cylinders the centre one will serve 4 - thats bad, unless its double barrel or something. Whatever, the 3 carbs wouldnt be identical.

More likely: The 3 carbs feed a single manifold as i predicted. This manifold uses 3 double barrel carbs as you have probably seen before, furthermore the manifold outlets can fit my attatched picture. 3 pics below illustrate this:
http://www.performancecoatings.com/FlatIntake.jpg
http://www.offyparts.com/images/offy_1072.JPG
http://www.riley-auto.com/images/intakes_0051.jpg

[henk4]

just check the position of the three carbs on the picture I posted. They are not evenly spread over the engine but to one side. It really looks like there would a place for a fourth.

The way you now designed the inlet side would mean 3 carbs, evenly spread over the engine centre.

[Ferrer]

Isn't that a bit like the Six-Pack Mopar V8s, only halved?

[jediali]

Originally Posted by henk4

just check the position of the three carbs on the picture I posted. They are not evenly spread over the engine but to one side. It really looks like there would a place for a fourth.

The way you now designed the inlet side would mean 3 carbs, evenly spread over the engine centre.

it does not need to be as strict as that, individual manifold designs vary. What would be of technical importance is the gemoetry of the ducts leading to the inlets from the manifold. If the carbureters deliver equal fuel/air mixture to each cylinder then its doing its job properly. longitudonal shifting of the carbureters is not critical in my opinion.

[henk4]

Originally Posted by jediali

it does not need to be as strict as that, individual manifold designs vary. What would be of technical importance is the gemoetry of the ducts leading to the inlets from the manifold. If the carbureters deliver equal fuel/air mixture to each cylinder then its doing its job properly. longitudonal shifting of the carbureters is not critical in my opinion.

but it looks rather suboptimal to me...

[jediali]

Originally Posted by henk4

but it looks rather suboptimal to me...

flathead and pushrod is sub-optimal ! I think there is too much I don't know about the engine to say its the best or not. But i know if i was asked to set them to the side I could still make em work.

[henk4]

Originally Posted by jediali

flathead and pushrod is sub-optimal ! I think there is too much I don't know about the engine to say its the best or not. But i know if i was asked to set them to the side I could still make em work.

anyway, thanks for the explanation, maybe we will get a US specialist on board to tell us about all the intricacies of sidevalves and carb set-ups...

[NSXType-R]

Thanks for the explanation for the ITBs guys.

Besides the power increase, they sound very nice too right?

[Kitdy]

Hijack time.

Now this is a good one. I got this photo of a Cadillac Sixteen's engine bay off of Wikipedia. By chance, I looked at the image creators' name to find it was the one and only Karrmann. He has his own user page on Wikipedia.

Anyways, I thought that was a strange cowinkey-dink. I assume that the Cadillac Sixteen's 13.6L engine is based off of two 6.8L V8s. I had a look at the picture and as I was looking at the exhaust, I noticed a repeat of a little pokey thingy that seemed to indicate a spacing of the two V8s. What are the little pokey things and is this an indication of twoV8s mashed toghether? If it is two V8s mashed together, what were the original engines used in normally?

[nota]

Originally Posted by Kitdy

What are the little pokey things

Those things are the studs & bolts which attach the exhaust manifold flange to the cyl head

and is this an indication of twoV8s mashed toghether?

Not really - it's just where the (nicely thick) flange happens to be divided as it extends along the head

[jediali]

The V16 is 32 valve, I am guessing its two regula pushrod V8s put together. Dont always go buy capacity when establishing engine DNA. If an engine is related its bore/stroke may change a wee bit.

[henk4]

Originally Posted by henk4

anyway, thanks for the explanation, maybe we will get a US specialist on board to tell us about all the intricacies of sidevalves and carb set-ups...

fresh material.

A Miller-Ford 1935, shot at the Festival of Speed. With a flathead V8 and carb set-up that makes absolute sense...

[hightower99]

I don't think that it is two V8s put together.

-The block shows no joint in the middle
-The head shows no joint either
-The bolt pattern on the cylinder head would tend to imply that the cylinders are equally spaced (as opposed to having extra space where the supposed 2 V8s meet).

Also the manifold is probably divided like that (every two ports) to make sure that the flange sits flat against the block. If it was one piece the joint would suffer because of thermal expansion.

I thought that this engine had SOHC as opposed to pushrods?

[jediali]

not "literally" two V8s bolted together. In the same way the AM V12 is two duratec V6s's bolted together, the point is you
-cass the extended block and cylinder heads
-redesign the crankshaft for balance and power delivery
-alter the camshaft timing programme
...plus loads of other less major design issues.

A funny comparison could be the V16T which uses two transverse Ferrari v8s with a longitudonal central output shaft