AJP with Pyramid Crank...

[cacatous]

What would an AJP be like if TVR developed a Pyramid Crank as opposed to the standard flat plane.

Would it make a good engine better?

[j_s_g]

cacatous said:

What would an AJP be like if TVR developed a Pyramid Crank as opposed to the standard flat plane. Would it make a good engine better?

It might stop it sounding like a couple of fiestas strapped together.

[matt101]

Quite a few other v8s about with flat plane cranks that dont sound as rough. Mine only seems to be noisey when cold anyway.

Whats a pyramid crank anyway!!

[cacatous]

I think it's what gives it an equal firing sequence.

I guess it would make it sound like a classic V8 engine.

I just wondered because Ferrari and Maserati will be sharing the same engine (4.2) just one will have a Pyramid crank (Maser) and the other a flat plane (Ferrari).

[daver]

But who'd want to change the sound of the Ferrari V8 at full chat - other than by bolting on a Tubi to get more of it?

[j_s_g]

cacatous said:

I just wondered because Ferrari and Maserati will be sharing the same engine (4.2) just one will have a Pyramid crank (Maser) and the other a flat plane (Ferrari).

I'm assuming you mean the one on the 4200 GT? Didn't realise they'd changed the crank between them. Curious. Ah well, you learn something new...

>> Edited by j_s_g on Wednesday 7th April 17:30

[j_s_g]

My understanding on it was that a pyramid (assuming that's another word for a cross-plane crank) has the last cylinder in a different position to the first, giving you end-to-end vibration. So you'd need to add counterweights to the crankshaft to cancel out the uneven forces. I think that'd only work on a V8 with a 90 degree V, though, meaning it wouldn't work on the AJP, which is 75 degree, right?

The flat-plane engine should be more responsive because of lower inertia, with a few other benefits (higher RPM, smaller, etc.) as well because of the lack of counterweights. There's loads of vibration with this arrangement, though, but in an expensive car you can mitigate it with lighter pistons, etc. and in a car like the Cerb, you're not as bothered about it running beautifully smoothly.

Hope I've got that right - my daddy taught me about engines a loooooong time ago now!


[Made this a separate post as I rambled on more than I was expecting!]

[cacatous]

So what would it be like Joolz?

Anyone thought of rebuilding the AJP to be the best it can be?

[j_s_g]

cacatous said:

So what would it be like Joolz? Anyone thought of rebuilding the AJP to be the best it can be?

Can't speak as the voice of authority, but I think you'd have to rebuild it in a 90 degree V which firstly wouldn't fit in the bay. Even if you could/didn't have to, you'd find that although it was smoother, it would probably be a bit bulkier, and would definitely be down in the performance stakes like-for-like. IMHO, of course.