Rebuilt engine now misfiring on RH bank

[pjenni12]

Just got my Cerb all back together after my body off and engine rebuild but failed the MOT yesterday on emissions.

It is misfiring on the RH bank and you can see backfiring behind the throttle butterflys. This is causing the HC count to go sky high.

So far I have checked it's firing on all plugs, fitted a new coil pack as the old one had packed up on 2-8. Swapped the tpots over from side to side. Tried all manner of diffrent tpot and throttle settings. The adaptives are near zero on the LH side but the RH is always -10 or more. The lamda looks like it is working fine, though not changed it yet. The plug leads are nearly new Castle Race engine HD ones. When checked with a syncrometer all the cylinders are flowing the same.

When I timed the engine up I spent ages checking that it was absolutly spot on so I'm sure that is right.

Any ideas?

[GreenV8S]

Have you put clean plugs in since fixing the ignition fault?

[high52kojak]

Cam timing?

[pjenni12]

GreenV8S said:

Have you put clean plugs in since fixing the ignition fault?

No, but I have had them all out and they look fine (not sooted up but light brown in colour) and are sparking.

If it is cam timing then I must be completely out. What I need to know is the firing order of the engine because I had to guess it after spending ages on here with no result.

So anyone know the firing order?

[clive f]

http://thumbsnap.com/v/Q40NZ8ha.jpg

this may help, also this one;
http://www.projectm71.com/Cross_FlatPlane.htm

[pjenni12]

I've seen both those pages but they don't help as the first is only lead location and the second explains the way it works.

The second page says they fire R-L, R-L, R-L, R-L and starting with no 1 so I presumed that no 2 would be the 4th to fire as you would want it as far away from no 1 as it's on the same journal.

Edited by pjenni12 on Sunday 2nd August 13:45

[GreenV8S]

pjenni12 said:

firing order of the engine ... had to guess it

Why didn't you mention that in the first place? Obviously you've got the plug leads connected up wrong.

If you want to find the firing order for yourself, just take the cover off and watch the valves opening. Each time you see the valves crossing (exhaust closing, inlet opening) you've got TDC on the exhaust cycle for that cylinder. Crank the engine over twice and you have the firing order of all cylinders.

ETA I meant crank it over with a spanner on the front pulley, obviously.

Edited by GreenV8S on Sunday 2nd August 14:36

[pjenni12]

When I referred to timing I meant basic engine timing not ignition timing.

I have fitted the leads in the same order as shown on many places on here.

When I fitted the new timing chain it is possible to mechanically time the engine up with two different firing orders. But one of them has cylinder 2 following cylinder 1 which I presumed would be incorrect as the are both on the same crank journal.

So what I need is the firing order of the engine ie 1,8,4,3,6,5,7,2 (rover V8)

[GreenV8S]

pjenni12 said:

When I referred to timing I meant basic engine timing not ignition timing.

You mean cam timing.

If you don't know whether you have got that right, then what chance is there that anything else is right?

[a1rak]

this is off topic so sorry I can't help with the firing order but how long did it take you to remove the body from the chassis. Was it a easy or difficult job. What has to come out / off before you can seperate the two parts.

[pjenni12]

a1rak said:

this is off topic so sorry I can't help with the firing order but how long did it take you to remove the body from the chassis. Was it a easy or difficult job. What has to come out / off before you can seperate the two parts.

My rebuild is on here :- http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Basically you need to remove most of the trim to access all the body bolts, you also need to remove all seatbelt fixings as they go through onto the chassis. Disconnect the fuel lines front and rear and remove the exhaust manifolds (if your leaving the engine in). Etc.

[pjenni12]

GreenV8S said:

pjenni12 said:

When I referred to timing I meant basic engine timing not ignition timing.

You mean cam timing.

If you don't know whether you have got that right, then what chance is there that anything else is right?

Exactly! Though I know everything else is right but that.

There have been plenty of people on here that have rebuilt there own engines so someone must know the cam timing order.

[GreenV8S]

pjenni12 said:

There have been plenty of people on here that have rebuilt there own engines so someone must know the cam timing order.

I don't know it for that engine, but I've told you how to find out for yourself.

[pjenni12]

GreenV8S said:

pjenni12 said:

There have been plenty of people on here that have rebuilt there own engines so someone must know the cam timing order.

I don't know it for that engine, but I've told you how to find out for yourself.

Yes but that will only tell me what I already know as it's possible to put the cam in 180 degrees out.

What I need to do is look at someone else's engine.

[clive f]

here are some pages from the engine rebuild manual, you will need to know the halfway mark between tdc for pistons 1 and 2, so that you can then see if the cams are in the right position as in the diagram at the bottom of the first page.
not sure on how you can easily achieve this with the engine in the car, as the marks are conviniently on the damned flywheel, so a couple of dial guages in the plug holes of 1 and 2?

hope this helps anyway;







yhm.

Edited by clive f on Sunday 2nd August 21:58

[APB_V8]

Hi Clive

I am rebuilding my 4.2 after the crank snapped by taking the best parts from my old engine and one I got hold of with a cracked sump. I have been looking for this information all weekend, so a big thanks for posting this up. I have seen mention of this AJP manual but have never found one. Are they available and if so where?

Thanks in advance

Andrew

[itiejim]

APB_V8 said:

Hi Clive

I am rebuilding my 4.2 after the crank snapped by taking the best parts from my old engine and one I got hold of with a cracked sump. I have been looking for this information all weekend, so a big thanks for posting this up. I have seen mention of this AJP manual but have never found one. Are they available and if so where?

Thanks in advance

Andrew

You have mail!

[spitfire4v8]

If you timed one bank up 180 degrees out do you think that bank would run at all? no didn't think so. So common sense would dictate you're probably somewhere close.
You don't need to know the firing order to set the cam timing, all you need to do is put that bank at TDC on cyls one and four and set whichever valves happen to be on overlap to equal lift.
If you have some work being done by the badly running bank it implies you're not a million miles away from being correct.

This is assuming it is a cam timing issue, which personally I don't think it is as the symptoms youre describing dont sound like it, but happy to be proved wrong. i suspect the issue is more basic than that, but what it is is anyone's guess

Edited by spitfire4v8 on Monday 3rd August 08:56

[pjenni12]

Cheers for your wisdom Joo, I was beging to wonder that too, but i was running out of ideas!

As for setting up that was exactly what I did using a TDC tool and setting equal lift on overlap.

So any ideas whats causing the missfire at medium load and a constant negative adaptive.

So far I have fitted a new coil pack, checked the plugs, leads, swapped the tpot side to side, adjusted the balance rod and all the cylinders are flowing the same.

The lambda readings are fluctuating as expected so not changed that, do you reckon thats where i'm going wrong?

Edited by pjenni12 on Monday 3rd August 09:14

[darreni]

Make sure the lambda connectors are attached to the right sensor.
Its easy to connect the left hand sensor to the right hand bank.