Engine Loom

[Steve B]

Which hints towards the coil pack being fired on the wrong stroke for some reason.

So other than the cylinder head, nothing else has been changed?

On this bank the cams have been out twice...
The first time so we could turn the pistons over to have a good look at the bores on bank 2
And then out again owing to us getting the G & J cams the wrong way round on this bank 

[Marks DTM Calib]

Ok, and the cam sprockets were fitted correctly e.g. exhaust aligned to notch 1 and inlet to notch 2?

(note: just checking the obvious  )

[JamesV6CDX]

Ok, and the cam sprockets were fitted correctly e.g. exhaust aligned to notch 1 and inlet to notch 2?

(note: just checking the obvious  )

Yep, the 1-3-5 exhaust cam was fitted into keyway marked '1' - and the inlet cam into the one marked "2' - I'm pretty sure I got steve to check, before I tightened them, just for absolute certainty....

I'm starting to think we need to check this again, though...

I don't suppose something daft like the cam sprocket dowel could have come adrift  The cam was held using the hex part at the end, and the pulley bolts correctly tightened... 

[Marks DTM Calib]

I am just working through the basics of what could cause the issue. 

On the 1-3-5 bank, the key way slots are 180 degrees between each so no valve damage but the spark will be firing on the wrong stroke.

I assume no paper towels have been left in the inlet or similar? 

[Steve B]

I am just working through the basics of what could cause the issue. 

On the 1-3-5 bank, the key way slots are 180 degrees between each so no valve damage but the spark will be firing on the wrong stroke.

I assume no paper towels have been left in the inlet or similar? 

No chance

[JamesV6CDX]

I am just working through the basics of what could cause the issue. 

On the 1-3-5 bank, the key way slots are 180 degrees between each so no valve damage but the spark will be firing on the wrong stroke.

I assume no paper towels have been left in the inlet or similar? 

The bottom line is, when the 1-3-5 cams were in the wrong place, it ran OK at idle, albeit a bit lumpy, it would run unassisted, and then eventually put the misfire codes up for that bank.

Since the cams were swapped into the right place, the engine immediately ran like a sack of poo with immediate misfire codes on that bank

Although we are confident on the pulley fitment and timing etc, I can't help thinking we need to go over this again, and inspect the camshafts/lifters etc very closely...

[Marks DTM Calib]

Considering that you have good compression and the lifters are quiet would suggest that the valves are ok.

Its confirmed that the spark is (possibly) good and fuel is there, so there must be a more fundamental reason why the engine is not firing on that compression cycle. 

There is some popping and banging when the ignition system is connected hinting that something is burning all be it at the wrong time.

[JamesV6CDX]

Considering that you have good compression and the lifters are quiet would suggest that the valves are ok.

Its confirmed that the spark is (possibly) good and fuel is there, so there must be a more fundamental reason why the engine is not firing on that compression cycle. 

There is some popping and banging when the ignition system is connected hinting that something is burning all be it at the wrong time.

My gut feeling is that we whip the belt off and check the camshaft sprocket alignment to be absolutely certain of this, even if to rule it out

[Marks DTM Calib]

It might be easy enough to check just by removing the cam cover.

[JamesV6CDX]

Steve I might try and get up to you tomorrow, I won't be able to do a late one though as I'm working earlies the next day... 

[Steve B]

Do you want me to strip down get the cam cover off get engine at TDC and get camera out 

[Marks DTM Calib]

Pop the cam cover off and set to TDC with cam timing marks aligned as per belt fit (pop the bolts out the top of the timing cover so you can ease it back to see), observe the cam lobe positions on no1 cylinder (they should both be pointing upwards).

[JamesV6CDX]

Do you want me to strip down get the cam cover off get engine at TDC and get camera out 

You would find TDC roughly by eye, when no1 is at the top of it's stroke and the cut out on the crank sprocket is at 6 o clock... but if you're not confident, I'll do it for you..

I'm just aware that after tomorrow, I'm working for about ten days straight, so wouldn't get up to you until around 06 April, unless I booked a day off..

[Marks DTM Calib]

Do you want me to strip down get the cam cover off get engine at TDC and get camera out 

You would find TDC roughly by eye, when no1 is at the top of it's stroke and the cut out on the crank sprocket is at 6 o clock... but if you're not confident, I'll do it for you..

I'm just aware that after tomorrow, I'm working for about ten days straight, so wouldn't get up to you until around 06 April, unless I booked a day off..

Timing mark at 2ish on the pulley/cam belt cover 

But cam timing marks need to align with rear cover to   

[JamesV6CDX]

Do you want me to strip down get the cam cover off get engine at TDC and get camera out 

You would find TDC roughly by eye, when no1 is at the top of it's stroke and the cut out on the crank sprocket is at 6 o clock... but if you're not confident, I'll do it for you..

I'm just aware that after tomorrow, I'm working for about ten days straight, so wouldn't get up to you until around 06 April, unless I booked a day off..

Timing mark at 2ish on the pulley/cam belt cover 

Sorry.... I was referring to the crank sprocket (the one the belt runs on) being at 6pm at TDC, rather than the outer pulley which drives the aux belt - as you rightfully say this would be at 2pm