AJP8 firing order?

[guillemot]

Hello all - not actually a Cerbera owner, but trying to get all the info I need to sort a blueprint of my O/H's beloved Cerb. Dan at black art graphics has done all the drawings, and it looks wonderful so far, but I'd really like to locate the firing order as the final detail.

The engine is an AJP8 4.7, would anyone know what the firing is for this engine?

Thanks in advance!

[jamieduff1981]

Left bank front is cylinder 1 with 3, 5 and 7 behind. Right bank is 2,4,6,8 from the front.

Firing order is 1,4,5,2,7,6,3,8

[guillemot]

Oh thank you so much!

Edited by guillemot on Wednesday 11th February 19:22

[jamieduff1981]

Cylinder numbering definately 100%.

Firing order is based upon other references on this forum. It does give equal spacing between firings for each coil pack though (which would be correct - i.e. odd-even-odd-even-odd-even-etc) and moves sensibly around the crankshaft which is conventional to avoid winding the crankshaft into a knot.

Joolz from Kits & Classics, Dom from Powers, Jason from STR8SIX or Andy from APM will have first hand knowledge from building and mapping them though.

It certainly appears correct

[Mad Mark]

This was posted on here a while back.

[ukkid35]

Might be worth removing the reference to Magnecor as most people see to find them more hassle than they are worth (not to mention the expense).

[Mad Mark]

Personally I agree. I am not a big lover of Magnecors. They don't fit too well and as you say very expensive. Two of mine broke very soon after being fitted too.

[pmessling]

I've had no problems from my leads from them so far. Been on the car four years now. Touch wood

[jamieduff1981]

My new Magnecors turned out to main cause of my recent severe misfire. They're now in the bin and a £60 set of leads from Racetech are on the car and working properly.

Incidently, the diagram only shows the cylinder numbering and which coil pack terminals correlate with which cylinder. It doesn't show the actual firing order

[tvrgit]

The diagram shows the odd firing order as "

1 3 5 7

and the even firing order as

2 4 6 8

jamieduff1981 said:

Firing order is 1,4,5,2,7,6,3,8

Separating that out into banks, this has the odd and even cylinders firing in this order"

1 5 7 3
4 2 6 8

One of those is wrong. Unless, of course, the arrows in the coil pack diagram showing "direction of rotation" have nothing to do with the order that each lead is fired.

[Krog 4.5]

this firing order cant be correct with that bank numbering because with 8 cylinders over 720 degrees of rotation for a 4 stroke we need a spark every 90 degrees (lets assume the engine is 90 V to make it simple - its 75)

The crank pins are UP DOWN DOWN UP. the first two spark events must be within 90 degrees of each other. Cylinder 1 is up which is fine, but then cylinder 4 will only be half way up from BDC so it is not ready to spark. Piston 2 or 8 could be fired as the second spark.

Edited by Krog 4.5 on Friday 15th May 10:07