Carbs and rockers and other conundrums

dmblbit

dmblbit

Active Member
Apologies for lucky dip of topics.
1. Trying to test brake performance in driveway, but car won't accelerate. Ignition timing checked out ok. Inspection of plugs reveals some are sooty black and some are not, so I suspected one of the carbs not getting as much fuel as the other. However, my intuition that the drivers side carb feeds the passenger side head and vice versa must be wrong, as I have one clean plug and one sooty one next to each other in the same head. So, it appears that the inlet manifold has some very strange internal meanderings. Is this correct? If so, does anyone know which carb feeds which cylinders?
2. Adjusting the slow running mixture screw on drivers side had no effect whatsoever, nor did raising the lift pin, so assumed (correctly on dismantling carb - float chamber beautifully clean . . . . and dry) that no fuel reaching here. Pump seems to be pumping fuel OK, but if I cover the outlet with my thumb, it stops with no obvious pressure - I am assuming this is because it just diverts back to the tank and not because the pump is feeble. Is this correct, or have I got a dicky pump too?
3. The needle valve did appear to be slightly sticky. It was a plastic one with a spring loaded pin at the float end - I have replaced with a solid brass one without the spring loaded pin, but with what looks like a composite "seat" which I found in my carbs bits and pieces. I am assuming the brass one can't work any worse than the other one (unless it gets stuck open of course), but out of interest, which is the better/more modern item?
4. While drivers side carb is off I have removed the very grubby rocker cover to check for oil delivery inside (a bit tappy in there) and to clean it up a bit. Wished I'd left it alone. Inside here everything is covered in black coke/burnt oil which even to my untrained eye does not suggest a very healthy engine. I hesitate to ask, but have to know - what is most likely cause for this?
5. Have started to clean the inside rocker cover and the rocker shaft, but it is not a very uplifting task. Is there any easy way of doing this? Maybe a product that dissolves the muck without also dissolving the metal?

Steve
 
dmblbit said:
However, my intuition that the drivers side carb feeds the passenger side head and vice versa must be wrong, as I have one clean plug and one sooty one next to each other in the same head. So, it appears that the inlet manifold has some very strange internal meanderings. Is this correct? If so, does anyone know which carb feeds which cylinders?
Click to expand...

NS carb does 1467, OS does 2358
 
When i recently painted my rocker covers, I just used engine degreaser and a wire brush bit on a drill for the inside.
You could probably use carb or brake cleaner, they're fairly severe.
Do you have new gaskets? The old cork ones will likely fall to pieces when you clean up the covers..
My oil pressure improved dramatically when i replaced mine with rubber gaskets.
Jim
 
Harvey: I'm going to have to take another look, because 1 was clean and 5 was sooty, but from memory 4 was clean but 6 was sooty which doesn't make sense - will take them all out and report back - maybe there is something else going on.

Jim: I have managed to clean up the inside and outside of the cover using just that method, but did not enjoy it very much. I was thinking more about cleaning the rocker shaft itself. I'm thinking of trying the Gunk and then borrowing wife's steam cleaner while she's not looking. I have managed to keep the gaskets intact so far but they are quite hard so will have to source new ones anyway. I am puzzled as to why renewing the gaskets improves the oil pressure though - can you explain?

I have read with great interest other threads concerning painting and polishing of rocker covers, and am fighting back a very strange urge to paint them Almond with matt brown detailing to match the rest of the car (Almond and rust). There appears to be a groundswell of anti-Almond sentiment out there, but I have to say that while it's not my favourite colour of all time (my Dad had a blue 2000, and father in law had a lunar grey 2000 - both brilliant colours on the P6) Almond is much preferable to my other car which is slightly matt Tobacco Leaf with rust detail round the bottom edges and aluminium detail on bonnet and boot lid.

Steve
 
dmblbit said:
4. While drivers side carb is off I have removed the very grubby rocker cover to check for oil delivery inside (a bit tappy in there) and to clean it up a bit. Wished I'd left it alone. Inside here everything is covered in black coke/burnt oil which even to my untrained eye does not suggest a very healthy engine. I hesitate to ask, but have to know - what is most likely cause for this?

Steve
Click to expand...

I hate to say this, but it is usually the sign of a tired engine and is caused by the presence of combustion gases in the crankcase. It is possibly getting past the piston rings or valve stems. Have you tried a compression test?

dmblbit said:
I was thinking more about cleaning the rocker shaft itself. I'm thinking of trying the Gunk and then borrowing wife's steam cleaner while she's not looking.
Click to expand...

Strip it down and bung it in a bowl of gunk or other such engine cleaner and let it soak overnight. Don't forget to fill the shafts with cleaner and shake them well a few times to clean out the build up of sludge inside of them.

Richard
 
Here are the plugs. Couldn't fit my box spanner behind the heat guard to get number 8 out. But this is not what I expected. I was expecting the O/S carb which had no fuel would have lean mixture plugs and the N/S which did have fuel delivery would have the rich sooty ones. 3 and 5 are the blackest of all and they are apparently fed by the O/S carb. I am perplexed.



Here is the rocker shaft - in progress.



And oh dear oh dear oh dear - here is the inside of the head. This will have to come off at some point, plus I think an oil change is on the cards too.
 

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Right then. Rule nos 1, 2, 3, 4, 5, and 6: DONT PANIC 8)

Let's start with the bit that seems to be causing you most concern at the moment. Rover V8's like having their oil changed very regularely. The generally recognised norm is every 3,000 miles, along with the filter every time. Needless to say, that isn't what the manual says. Most people start with the manual and then try and stretch them a bit. Then the inside of their engines look like yours does. It doesn't necessarily mean there's anything wrong with it, although it isn't a promising start.

So there's certainly no harm in cleaning up the rocker gear. I'd be rather cautious about trying to clean the head itself up whilst it is still on the engine. You stand a chance of dislodging bits of c___p and them finishing up somewhere that's actually damaging. As it stands it is merely unsightly.

What is more interesting is your allegation of a tap from that area of the engine. The Rover V8 has no adjustment for the valvegear, that's taken care of by hydraulic cam followers, or "lifters" in American. So provided none of the rockers are too sloppy on the rocker shaft - they are meant to be fairly loose, just not cylindrical object in shirtsleeve! - any difficulty is going to be either poor oil delivery to the rocker shaft or something amiss with one of the cam followers. While you have got the rocker gear off, motor the engine on the starter motor with the plugs out. You should see oil appear from a small hole in the cylinder head where the front pedestal usually sits. If not have a poke around until it does. Then your nice clean rocker gear should take it from there and distribute it down the rocker shaft. You're not looking for a lot of oil or any spray, it should just dribble out quietly. If after this treatment there is still no improvement in the tap, it may be worth adding some hydraulic follower cleaner additive to a batch of cheap oil and then doing a second oil change after - say - 1,000 miles. If still no improvement, then grin and bear it until such time as a camshaft change comes around. You should never mix new and old cams and followers - they wear each other out if you do - so if any follower or the cam need changing you have to do the lot at the same time.

With luck that has taken the edge off the panic.

So on to the carbs.

At this stage their are two things to do. Firstly prove the supply of petrol from the pump. Again motor the engine with the plugs out and allow the pump to discharge into a glass jamjar or similar. Does it look a reasonable flow? And, no, I'm not entirely sure what criteria to use either, but it needs to be able to cope with an engine being run off load at say 1,000 rpm if you think about how fast the starter motor is turning the engine. So we are not looking to get a gallon a minute!! If in doubt it's simple enough to slap an overhaul kit on the pump - basically a rubber diaphragm and a couple of one way valves.

Next you need to check the float chambers of the carbs. You've already replaced the needle valve in the suspect carb, so now time to verify that it is now filling with petrol. It's motor the engine with the plugs out time again and then have a look. Likewise have a look at the other carb and verify that it is shutting off the petrol with the float raised. It's just possible that this carb was spilling all the petrol to the inlet manifold, leaving none remaiing to fill the first carb.

At this stage you ought to be ready to restart the engine and have a go at resetting the carbs. Harvey and I have a fundamental disagreement as to how to go about that, so best we leave you to catch up for a bit and then we can continue the tool box talk!

By the way - you should be approaching running engine. The test for how good a Rover V8 is, is the oil pressure when hot. So you can report back what yours is at hot idle and at hot revs - say 2,500. Then we can comment properly on whether or not you have a serious engine problem!

Hope that helps

Chris
 
Perhaps i've imagined the higher oil pressure..
I did fit the mallory distributor at the same time which may have a better seal?
I don't know how to explain it other than my circumstantial evidence.
I didn't drive the car for over a year so i may have forgotten what the pressure used to be :LOL:
No, in all seriousness I have better oil pressure than I used to have.
Frankly as long as it stays that way, I'm a happy man :wink:
Jim
 
Chris: many thanks for good advice, especially rules 1 through 6. Unfortunately I reassembled car before reading your response, so will have to retrace my steps, as car is still not running correctly. In particular, adjusting the jet on the N/S carb results in changes in engine speed as expected but doing the same on the O/S, the one I have just dismantled and rebuilt again, still has no effect at all, which suggests to me there's no fuel. So tomorrow I'll have to go through your checklist to find out where the fuel is ending up.

I didn't try to clean the head in situ for exactly the reason you offered - there's no way of ensuring you catch all the debris, and there's too many holes for it to fall down. I was very careful and a bit lucky and didn't damage the cork gasket. It's gone back OK and surprisingly enough isn't leaking - this could of course mean there's no oil up there - will check using your suggested method tomorrow. Could be my imagination, but the rocker area does seem quieter after reassembly, however now I think I'm hearing a rumbly rattle closer to the front of the engine, possibly timing chain (I hope not - back to rules 1 through 6 again I think). However, I'm also not sure it's sensible to try to interpret mechanical noises when the engine isn't running smoothly due to carbs being out of synch, so I'm going to try to sort that first. I'll also check the oil pressure at tickover and 2500. From memory pressure has always been very good on this car, so maybe there's hope for the engine yet - we'll see.

I'll keep this thread updated - the advice is very much appreciated - thank you.

Steve
 
Richard: Steam cleaner didn't work - just made the oil go creamy. Too impatient to wait for overnight soak so just used white spirit, wire brush and elbow grease. Engine might indeed be a bit tired - it's not been that well looked after. We'll see tomorrow what the oil pressure looks like.

Steve
 
:oops: :oops: :oops: :oops:

How embarrassing. After re-reading Chris's comments about fuel not reaching the O/S carb I had another look at the fuel gauge. Empty, and of course I had been running on reserve for a while. So I have put 10 litres of fuel in. She is running smoothly again, and I was also able to adjust the tick-over mixture on the O/S carb. There's a lot of work to do before she can go on the road (put the wings back on for a start), but she shot up the drive like a bat out of hell. It's just as well I did the brakes last week.

So, I am a clot, and am very sorry for wasting everyone's time.

For the record, with temperature normal, oil pressure is 30 on tick-over, and around 60 at 2500 rpm.

Tapping from rocker cover hardly audible now, but rumbly rattle from nearer the front still needs investigation. Will try running with fan-belt off tomorrow to eliminate alternator and water pump.

Have ordered a filter and some Penrite, but I'm thinking I'll put some cheap-but-clean-oil in with some engine flush in the meantime, while I'm waiting for these to arrive.

Apologies again.

Steve
 
There was a LOT of sludge in the rocker shaft and due to lack of flute playing skills I was not successful in covering all the holes to swill it through with cleaner. So I poked a long bit of cloth through instead - took ages, but did the trick.



On reflection then, I'll avoid the engine flush - thanks for the tip.

Steve
 

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dmblbit said:
For the record, with temperature normal, oil pressure is 30 on tick-over, and around 60 at 2500 rpm.
Click to expand...

Have you got an uprated oil pump on there, because that is high for a standard engine, even a new one.

Richard
 
I wish, but probably not - how could I tell? I assume that thicker fluid causes pressure to increase, and as I didn't do the last oil change, maybe it's not the correct rating? Or maybe it's the high sludge content that is the culprit.

Steve
 
The oil pressure suggests a good engine. 30 hot idle is about right for really good bearings. I'd still do a couple of oil changes in quick succession with naff oil to assist with sludge removal, just not with the addition of flushing oil. My betting would be that the front end knock will be water pump, but you're going about it the right way and we shall see if I'm right or not shortly!

Chris
 
Am just psyching myself up to go out and have another shot at it. Am I right in thinking that the water pumps are sometimes unwilling to come off? Or is that the timing cover?

Steve
 
http://youtu.be/YRaFORpEBCE

News, like the curate's egg, is good in parts. First good news is I have found the source of the rumbling rattle. Second good news is it isn't the timing gear/chain. Here is the bad news:

To remove the fan-belt I slackened the two alternator bolts on which it pivots, and then decided to remove them completely so I could take the alternator off and clean it. Having removed the second one the whole unit just fell off. It appears that someone (even more hamfisted than me) has been at the car and has sheared off the bolt which secures the adjusting strap to the water pump. A bolt and nut had been secured to the end of the strap to locate it in the hole, but it was a loose fit, hence rattle and rumble. You can actually just about see it at the very end of the video, but needless to say I didn't spot it until the alternator fell off in my hand. Without fanbelt the noise disappears. So it was just resting there. It looks as if the bolt has sheared off about 1/2" in. Any ideas is to how to remove it would be greatly appreciated.

The other bad news is that, having gone very quiet last night, a tapping sound has re-appeared in the O/S rocker cover, which leads me to suspect oil flow problems, so I think I'll try the double flush with cheap but clean oil before running the engine any more.

The other news is that, on having another look at the oil pressure I was talking rubbish last night. It is around 30 at tickover, but is actually closer to 40 or maybe 45 at 2500 rpm - not the reported 60, so Richard was quite right, and there is certainly not an uprated oil pump in there:

http://youtu.be/o-pVTEg96Bk

While I was mucking about I recorded the exhaust note also - it sounds OK to me but please feel free to offer different opinions or diagnostic suggestions:

http://youtu.be/UShtjUPhZIk

Steve
 
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