New cam and lifters are in. Exhaust manifold and somewhat modified heat shield back on...

Part of the inside of the heat shield (the engine side bit has been missing since I got the car) appeared to have been rubbing against one of the header pipes. Some tactical tapping should have corrected that clearance, but if not - when it went back onto the manifold, I spacered it out with some M6 washers and longer bolts.

The bottom was pretty rusty too, so a section was lopped off with the grinder, then a few tack welds now holds it together.

I know some don't bother putting them back on at all - but under bonnet temps are high enough... I'd rather not risk it. The other side is actually a bit rattly, so I might take that off and give it similar cut/shut/weld treatment at some point.

The electric Volvo fan shroud also had a bit of a small upgrade - welded captive nuts on the inside. Should the fan fail down the track, replacement now won't need pulling the top hose off to remove the whole shroud - the fan can be unbolted in-situ and swapped out.

Other than that... the inlet manifolds are all on, wiring loom is in, and most of the front of the engine and sump is back together. The wind yesterday was just too annoying to carry on. Hopefully the rest of the exhaust turns up in the next few days, so it can all be fitted and cam break in done in an evening during the week.

I heat wrapped the manifolds on a mates 4.6 HSE and it was no hotter..

Personally i never refit the tin...

Looks to be coming together, ya going to do a first start video?

I'd thought about wrapping them as I did that on my last P38 with good results - I just haven't got any wrap to hand this time.

Probably not on the video front, as it'll be a case of bleeding coolant while not letting it idle to break the cam in, and I don't remember it being a fun game last time :)

A fast idle stick can work wonders LOL

I bleed the coolant before starting the engine. Take the overflow pipe off the radiator, fill the header tank then squeeze the top hose and plug the overflow with a finger when releasing the hose so it sucks coolant in and blows air out when you squeeze the hose. Keep doing that until coolant comes out of the overflow (it'll take a while and you'll need to top the header up a few times). Then put the pipe back on and carry on only this time plug the hole in the top of the header where the jet of coolant comes back into the header. Eventually, you'll no longer be able to hear bubbles in the system and at that point you know you've got the air out. Only then start the engine and give it some revs.

Exhaust parts finally turned up yesterday, and I left work early to stock up on more essentials - another mountain of bog roll etc. Oh and some food. And then on to finishing off the RR.

Got everything back together, and the car just fought me the whole damned way. To be fair, the exhaust all appeared to go in pretty much fine. Finished up the wiring, refitted the starter etc. The wheel arch liner proceeded to jump out and twat me in the face giving me a nose bleed. Appropriate use of my foot then had it beaten into submission and clipped back in.

I'd been waiting on the exhaust bits all week and I'd then forgotten I needed some bungs to block up the currently unused LPG coolant lines. Ended up just looping the hose and putting a hose squeezing clamp tool on it to block the flow.

All the relays bar the ABS pump back in, key to pos2, no smoke, no pops. Turned over a few times and no nasty noises. So - let it start. And after getting the fuel rail filled up - it did.

Annnnnnd massive exhaust leak. Kept the revs high while trying to work out where it was coming from - it is very eager to rev now, and sounds lovely, until it started seemingly cutting fuel and dropping the revs, which repeated almost like it was being caused by the ECU.

The leak was coming from bank 1 downpipe joint (passenger side for us RHD). For some reason, the flanges hadn't pulled tight, and trying to tighten the fixings wasn't having it. Attempted to loosen them off to separate it and inspect, and despite everything going together without binding etc, one of the studs just snapped clean off. Several new interesting words were then invented.

So now I have the other manifold off... it might have been possible to drill it out in-situ, but given the passenger manifold is piss easy to remove, it made no sense to try.

Welded a bar on to the remains of the stud and after it lost that fight, out it came. I've taken all three out now, as the threads are buggered. Will drill the remains out and then nut and bolt it.

I am hoping the fuel cut oddity was either a) still air in the fuel rail, as it only ran for about a minute total or b) the massive exhaust leak causing the o2 sensor to screw up the injection, which I think makes more sense as it appeared to start doing it after about the time I'd expect it to go closed loop.

Back together, cam bed in.

Still squeaking when driving on throttle. Slightly frustrating.

Right - I'm really running out of ideas on this and I'm not sure what to look at next.

Things I have done that should rule out certain areas:

1. Pulled entire inlet and valley gasket arrangement apart and refitted with new gaskets after cleanup.
2. Removed LPG nozzles and blanked with locktited M6 bolts. Vacuum port on inlet blocked up as not currently required.
3. Replaced camshaft and followers etc. Cam broken in.
4. Front cover resealed.
5. Checked oil pump gears - look fine, were replaced 18 months ago because we had it out and in bits to replace the flex plate.
6. Water pump changed (was noisy and leaking before)
7. Sump resealed.
8. Both exhaust manifolds removed, looked over, refitted with new gaskets. Heat shields tidied up and secured.
9. Any cooler pipes etc touching body or framework have been isolated or adjusted to clear.
10. Can't see any cracks in the flex plate.
11. Removed front prop as I did find some play in both ends - I couldn't see this making a difference as the noise can be heard when loading up on the brakes in drive.
12. Made up a clamp on mic/pickup like an electronic stethoscope and clamped it on to the gearbox, bell housing, engine sump, engine lifting point, and went for several drives - could not pickup the noise over this at all. Could hear other internal noises though so I am relatively confident I should have heard the damned noise if it was present at the locations.
13. Had the gearbox sump off to inspect for glitter, nothing seemingly alarming.

I can't see how this noise could be coming from the engine. I can't see any sign of a head gasket blow on the outside of the block, nor was there any evidence of one in the valley. The noise is identical to the engine work and removal of LPG. Won't do it free revving, will happily do it when accelerating or loading up the gearbox foot on brake when hot.

I am at a loss... any suggestions?

It could be the Torque converter the stator within the converter uses an overrun mechanism with a series of clutches, when they start to deteriorate they, can cause a rattling/chirping noise.

Being in the box would explain the "". Won't do it free revving, will happily do it when accelerating or loading up the gearbox foot on brake when hot."

That must be really irritating that after so much work you've still got the same issue.

Breaking in the new cam is one thing I'm really not looking forward to on our new engine. Going from 0 - 2500rpm on a brand new engine the second it starts seems awfully brutal but if that's what the instructions say!

David.

It is required!!

Make sure you use shit oil too for the break in!

Parts have to conform together!!

I don't suppose it could be a knackered engine mount allowing things to move when under load?

That's only the second time I've done a cam break in - I didn't like it any more this time either! I'd love to now go out and give it a bit of a hooning to see if we've got some more power back - but so far I've just driven it round a few times being back at square one.

Sure, I could just drive it as-is and eventually, maybe, the issue may make itself more obviously known. But the whole reason I bought my first P38 was wanting something V8 that wasn't any old saloon or something that didn't offer anything over a normal car. I drive it because I enjoy the noise it makes. This currently just sounds like its broken... like the ubiquitous hatchback with a throwout bearing that is moments away from letting go, or the Transit running on 3 being ragged off its tits. I don't drive my P38 everyday, I only really do now because I want to. Which I really do - but not sounding like this.

I'll happily pull the gearbox out if it comes to it, roping a certain Marty who has definitely volunteered already into it :) But as I'm sure you can imagine - it would be nice to narrow it down fairly definitively before taking that plunge. Frankly I'd rather pull an engine out again than drop the gearbox. I could do that and just swap the TC... but if you're going that far, wouldn't it make sense to change both?

Minor update... and actually, as a few have suggested just this evening - mount related. I have discovered that the passenger side engine mount is backwards, so the throughbolt is hard against the framerail. The rubber is also a bit perished - I can shift the engine over about 5mm by levering with not massive force in the mount using a spanner. Tomorrow once I've refilled the gearbox, I'll see about lifting the engine up, extracting the mount and turning it round. While I'm at it, the drivers side mount can be loosened off and the engine pulled over slightly. I do remember it being a pain in the arse to get back in when we had it out for the flex plate - but we didn't remove the mounts, so it has been fitted backwards since before my time. It might be the rubber has perished over time and now allowing more flex perhaps... I can see the drivers side is fitted correctly, but couldn't easily get leverage on it to give it a wiggle.

Which might explain not hearing anything on the clamp microphone anywhere on the engine - if the noise has been isolated by the mount. Could all be wishful thinking but nothing to lose I suppose.

Hats off Sloth, you're really going after this!

Don't let it hear me say this, but I might have cracked it.

Popped to my parents to pick up the pump filler to get the ATF back into the gearbox (social distancing style, obviously), and while there, I nabbed the MAF off of my dad's P38 as its currently not in use. I'd noticed mine at idle is reading 16 or so, where the internet suggests it should be 20-25. Put his on, reset adaptives (again) and it still read about the same. The only thing I hadn't checked on either was what it should read at higher engine speeds - because I couldn't remember the figures, and I'd been making enough noise with it on the driveway.

Went for another drive, expecting to only get half way up the road where there is a turning circle and then to come back - and it was glorious. Did 5 miles or so, and did a lap of a very steep hill a couple of times that puts a heavy load on any engine and everything sounded as it should.

So - has this noise actually been pinging all along due to intermittently dodgy fuelling? The trims have looked okay when I've been checking them, but I have had additive adaptive faults for both banks for a LONG time - I put this down to the LPG map in the past, and then to the hilariously worn cam when I found that. The live data didn't seem to make sense with the fault codes present. I don't know if this has now cleared - I will check in a few days if things stay good.

Next step was to take it to work and see how it went. But that required it get a bath... it was properly minging inside and out with oil, ATF and general grime over the sides and bonnet where I'd been dragging myself out from under it. And all manners of dust and the same inside. Plus several weeks of storing most of the top engine bits inside - lovely. The roof hasn't been cleaned properly in well over a year too - so out came the steps. The bonnet needs a respray, and there are quite a lot of little areas that need corrosion sorting at some point.

My 16 mile commute of mixed motorway and the bit around down ended on 20.2mpg. Now - I hadn't reset it before changing the MAF so I don't know if that is down to the new cam, MAF, or both - but if it wants to keep returning that kind of figure, I'll be a happy bunny. Later in the week I'll hopefully be ordering a brand new Bosch MAF.

If it was fuelling and what you've been hearing all this time is pre-ignition, check that the knock sensors are still connected as they should have detected it and retarded the ignition of the appropriate cylinder to stop it. Admittedly GEMS so not quite as intelligent as the Motronic but when doing the core plugs on the Ascot I found that one of the knock sensors wasn't connected and the plug was so mangled that it couldn't be connected anyway. Nothing at all shown from reading fault codes.

That's great news that it's running as well as it is! She's a nice looking motor too!

Great news! And you've got a refreshed motor as a side-effect.

I like the way you've gone straight to cosmetics :) Approved!!

:) It doesn't scrub up toooo badly considering the failing paint.

Driven in again today and so far so good. I need to learn to have a less heavy foot given its petroleum only for the time being - and actually its kind of nice wafting along with it a bit quieter. Though I think it is a bit too quiet... the centre silencer will probably be going in the near future - but it was all I could get in a (well, supposedly) reasonable time frame.

The knock sensors are definitely connected, but that isn't to say they're either working or even enabled - given the oddity of my P38. Further investigation required at some point.

Well... that was short lived.

Noise is back. Resetting adaptives does not make a difference. Still got the same mixture faults, and the idle trim is higher than ideal.

I have a leak down tester that should arrive tomorrow to see if anything untoward is happening internally. Going to try a significantly newer MAF on the weekend than either of mine, but if that reveals nothing or makes no difference, it may be curtains for this one. I can't keep pissing around with it, and it is now really starting to test me.

Whether I move on to another P38, or spend the money I don't have on the compushift and shove the M57 in - I don't yet know. Or I break it and give P38s a rest for a while - I am undecided.