Lady Charlotte - 1966 2000SC

2 weeks after the head came off the engine is back together and running smoothly. The good Lady also has a fresh MOT :) In the words of the MOT tester "you won't be surprised to hear she passed".

It's taken a bit longer than I'd planned though. I had hoped to have the head back last weekend to give me a full week to prep for the MOT. As it happened, worn valve guides delayed the head coming back from the machine shop. I got the call on the Wednesday that the guides were worn to excess, I called Wins for a new set of guides hoping they might get there early enough on the following Friday so I could have the head back. Unfortunately the guides didn't arrive until late afternoon on the Friday so I had to wait until the following Monday to get the head back. It was worth the wait though.



The valve seats were cut to the new valves. The shop vacuum checked the exhaust valves so no need to lap in. The inlets were lapped in as it's not so easy vacuum checking them with the integral inlet manifold.



No sign of valve seat recession, all valves looking like these



Everything got removed from the head so I could fit new gaskets all round. How many have looked in here?



Including removing one of the inlet manifold top cover bolts that sheared. These bolts are a No 10 UNC with the long ones 1 1/4" and the shorter ones 7/8". Took me a while to source replacements but I got there eventually. I also bought some equivalent nuts to extract the sheared bolt



Worked a treat :)

I spent most evenings last week rebuilding the head and fitting it back on to the block. My plan was to do the valve clearances on Friday, complete the rebuild and start her up on Saturday. The old saying "no plan survives contact with the enemy" held true as ever. It took me three attempts to sort the valve clearances. Half of them were zero, and all you can do with that is re-shim to the maximum value (0.015 exhaust and 0.010 for inlet) and check again. The first attempt at that left a couple still with zero clearance, so a further re-shim was needed. That opened up most to 0.005, which is still too tight so a third re-shim was required. I did all this with the head on the block, using some drilled out nuts as distance pieces.




Once that was sorted the remainder of the ancilliaries were refitted and the engine was hand cranked to make sure everything turned freely. That was Saturday. I'd taken Monday (today) off to take the car in for its MOT, but I also wanted to sort out the rather crusty bottom of the right hand D post. There had been water getting in that side for a while and it was a definite MOT failure point so it was time to bite the bullet and go poking around. As always the extent of corrosion is always far more than it looks. Chop-chop.....





So a couple of new bits knocked up and tacked in. That was Sunday morning (ish)....and then I ran out of welding gas.....




Up early this morning to get some more gas and the job was finished by around 10 this morning. Phew. Delivered to local garage for MOT and picked up at 5 with a nice new ticket YAY!

Dave
 
Fantastic to see such a quick turnaround :) Hope it didn't stop you getting around for too long....
 
Fantastic to see such a quick turnaround :) Hope it didn't stop you getting around for too long....

I had the use of my wife's modern for the two weeks Lady C was off the road. I'm now trying a few options to see if I can prevent the valve burn-out re-occurring in a similar time-frame. I've decided to switch to higher octane fuel from the usual 95 stuff I've been feeding her. I've also got some of this stuff to see if it helps. It seems to have some good reviews. It might just be snake oil of course, but I think it's worth a go.

710buWUpkOL._SL1500_.jpg
 
Bet the machine shop were happy to work on something a bit different.

Be interesting to see how the valves last.

Colin
 
It is possible that it's just from a time before engines were used to such large mileage... My grandad used to take the heads off his p4 100 and 75 every 12 months to decoke and check apparently. Might have been overkill, but a service obviously meant something different back in the 1960s... We're used to modern cars that will all do 200000 miles without issue. People complain about the k series popping head gaskets but they'll usually do 80000 before that happens...
 
It is possible that it's just from a time before engines were used to such large mileage... My grandad used to take the heads off his p4 100 and 75 every 12 months to decoke and check apparently. Might have been overkill, but a service obviously meant something different back in the 1960s... We're used to modern cars that will all do 200000 miles without issue. People complain about the k series popping head gaskets but they'll usually do 80000 before that happens...

That's a good point Rich. I remember my dad regularly decoking the head on his Mk1 Cortina. Perhaps a compression test every 6 months and head off every 12 is appropriate preventive maintenance for the mileage I cover. Then inlet valve shoulders were caked in carbon when I removed them.

Dave
 
So, in my quest for better running I've done quite a bit of study on SU carbs, needles, springs etc and made a few changes to the carb. First off I bought a new piston spring (green) and a new RN needle. A green spring should exert a force of about 12oz, or 350g in new money. This is the old new springs side by side, old on the left



You can see how much the old spring has shrunk with the years of constant use. I measured the old and new springs to see what the difference in strength is. To measure this you need to cut a piece of card the length the spring will be at maximum compression. You can find this out by looking up the SU Carb Reference Manual. The piece of card serves 2 purposes. 1: it measures the maximum compression length and 2: it stops the spring from "pinging" out.

So old spring measures



and new spring measures



What does this mean exactly? Well the spring strength is designed to balance the throttle force lifting the piston for a given metering needle. So if the spring is too soft or too strong, the needle meters fuel at the wrong setting and affects the mixture for a given throttle opening. That's a very simplistic explanation, it's actually a lot more complicated than that; however, for the purposes of this application it'll do.

The new RN needle was then fitted and the carb was put back together ready for mixture checks with a Colourtune.

You can see the old RN needle below the new and the correct fitting of the needle below



This is the Colourtune reading at idle.


Not the easiest thing to photograph, but you can see the yellow colour indicates the mixture is rich at idle. I'm not too fussed about that because the engine spends very little time at idle. I'm more concerned with how the mixture looks under normal use so after running the car for a week with the old RN needle the spark plugs pretty much all looked like this:



A week of running with the new spring and new RN needle gave this result



Both look a little on the weak side of okay so very little change there. After reading a bit more I had a choice of either trying to polish the existing needle to give a richer result or trying a richer RE needle. The big book of SU tuning is a bit contradictory in that it states you should stick to choosing from the range of factory needles for a given application. It then goes on to state that doing this is pretty much a "stab in the dark approach" so needles should be polished for a specific setting and fuel etc. Rather than polishing the existing RN needle I've opted to try the RE needle. I'll let you know the results once I've run the car for a week on it.

Dave
 
It's pointless trying to get the carb set up to deliver the correct fuel/air mixture if the timing is not accurate. So I've also bought a new distributor from Powerspark. The distributor comes with electronic ignition built in and is set up to the original factory spec for the car. This is the old one



It's a 41119A which is correct for the car, but there's quite a bit of play in the main shaft. The new one is nice and tight, here you can see them side by side




and here's the new one on its own




The only slight change I had to make was to swap the vacuum advance units as the original has a screw thread attachment for the vacuum pipe whereas the new one is a push fit. I checked that both work before swapping them.

The timing was then set to 4 degrees BTDC and I also checked the maximum centrifugal advance, which was around 20 degrees. I've not checked the maximum advance with vacuum connected but it felt pretty responsive on a test drive. Once the RE needle turns up I'll fit that and test drive again. So that's all for the carb set up for now.

The other new toy I've bought is one of these suction devices for doing oil changes.



This one has a 6.5litre capacity tank and makes an oil change a much quicker affair. Slip the tube down the dipstick pipe and pump the handle to suck the hot oil out of the sump. Takes less than 5 minutes and leaves the only messy part as the oil filter swap :)

Dave
 
The other new toy I've bought is one of these suction devices for doing oil changes.

Dave, i'm sure it is going to be easier with this, but are you happy with the effectiveness of the procedure?
I don't trust suction oil changes, not even for my modern.
 
Dave, i'm sure it is going to be easier with this, but are you happy with the effectiveness of the procedure?
I don't trust suction oil changes, not even for my modern.

That's a fair comment Demetris. You can never completely drain the sump even with the sump plug removed, but you could argue that gravity is a more effective means of removing any nasties in the oil. The tube that goes into the dipstick pipe is only just slightly smaller than it, it's quite a close fit, so I'm happy that it's of sufficiently large enough bore to allow any particulates in the oil to be picked up. It also depends which way the tube goes when it hits the bottom of the sump ie does it go forward, back or to the side and if the car is sitting level, nose down or nose up. The oil and filter get changed frequently enough to minimise the risk of damage from excess particulate build up in the sump. Perhaps next time I do an oil change I'll suck out as much as I can then remove the sump plug and see how much more comes out.

Dave
 
What are your oil change intervals Dave? Does the old oil turn black?
I guess that i might be worrying too much, but there were cases that i was pouring some fresh oil in after the old oil had drained out and before replacing the drain plug, to flush out what might have remained at the bottom of the sump. I was using a decent mineral oil anyway, not anything fancy synthetic, so a few mililitres more at every oil change wouldn't break the bank!
 
Oil and filter changed every 2500 miles and yes the oil does turn black. Using Millers Classic oil.

Dave
 
Pat, there are no markings on the distributor body but it is a 25D4. The vacuum and centrifugal advance is correct for the 2000SC (perhaps more so since I swapped the vacuum unit), the TC is different. The website says it's a direct replacement for the SC and TC, but I contacted Powerspark to let them know mine was an SC and they sent me the correct distributor. They have them made to the factory standard specification for a range of cars, just tell them which engine you have and they can supply a distributor with the correct factory advance weights, springs and vacuum. Again, it might not be perfect for modern fuel, but it's a good benchmark to start from.

Dave

Dave
 
Dave, i'm sure it is going to be easier with this, but are you happy with the effectiveness of the procedure?
I don't trust suction oil changes, not even for my modern.
I have the same suction pump and use it on my classics & moderns -
On both the oil is initially really clean afterwards - not discoloured by remains of old oil (always feed the tube to bottom of sump)
It's really handy to decant into containers for disposal.

Mark.
 
I like the suction kit. I absolutley hate getting oil up the arm of my ovvies.

with the oil changes you do and the odd sump removal I am sure Lady C will be fine.

Colin
 
The suction method does seem a pretty good idea with such frequent changes (2,500 miles). Great quality photos on the carb work too by the way!
 
Next couple of jobs done! I've swapped the RN needle in the carb for an RE, which is slightly richer at cruising speeds. I'll report back once I've done a few miles.

I've also completed the conversion to an alternator charging system. The job is very straightforward but requires a bit of preparation and thought to ensure everything works. I sourced an alternator bracket from a later car, bought a new 18ACR alternator, some cable and the final piece was an old voltage regulator box. The first part was to sort the mounting bracket and make sure the pulley on the alternator lined up correctly with the existing fan and crank pulleys. As I said earlier, I sourced a later alternator bracket as shown below. The bracket consists of several parts, but the 2 main parts are the base plate that mounts to the engine block and the alternator mount that fits to the base plate via a couple of anti-vibration rubber mounts. Here's the bracket:



After disconnecting the battery (we're working with permanent battery voltage at several terminals where the risk of a short to battery earth is high) I removed the dynamo and mount and offered up the later bracket...only to discover that it would push the alternator too far forward. So I decided to split the mount and base plate so I could use the original dynamo base plate with the later alternator bracket as below:



and fitted



The first trial fit had the alternator sitting about 3/8" too far back. This was easily corrected with an appropriate spacer on the front mount to give correct alignment of pulleys as shown:



and final fitment



I was able to retain the original adjustable strap at the top of the alternator. The next job was to sort the electrical connections. I wanted to retain as much of an original look as I could and allow any future owner the ability to return to the dynamo charging system as simply as possible. The alternator is internally regulated so the external RB340 regulator becomes redundant.



It can, however, be used as a junction box to connect all the relevant high current cables together as well as the wire to the ignition light. Here's an old spare one I had stripped out



It's then a simple case of soldering a wire between the two "B" terminals (which are already connected) to the "D" terminal. This effectively connects the main 12V feed to the alternator, ignition switch and starter solenoid together like this



I cut off the "F" terminal as it's connected directly to the "D" terminal and I didn't want to inadvertently connect the ignition light wire to it. I still needed a way of connecting the two wires that form the connection to the ignition light from the alternator as this generates the field excitation and obviously illuminates the ignition light. To achieve this I made a short flying lead with a spade connector on one end and a ring connector on the other. This allowed me to use the screw hole at the top of the WL (warning light) terminal to create a link for the ignition light wires.



Having done this, all wires were reconnected followed by the battery. I did a quick check to make sure nothing had shorted then turned the key in the ignition to make sure the ignition light came on.....which it did. The engine was then started and a voltmeter used to measure the voltage between battery terminals. This showed a healthy 14.5V so the job was done.

The final job is to amend the vehicle wiring diagram to reflect the change. I think it's important to make sure the documentation reflects the actual vehicle so that future owners know what has been done.



My only slight concern is the lack of heat shield around the alternator. It doesn't sit quite as close to the exhaust downpipe as the dynamo did, but it's still in that area. Can someone with either a later 2000SC or 2200SC have a wee look at their alternator to see if it has a heat shield please. Thanks.

Dave
 
Back
Top