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Post by tommydp on Nov 8, 2011 22:45:50 GMT
Hi all! I've done some research on distributor drive gears and found there are differences between the 1800 and the Princess 1800 drive gears and am curious about mixing these would matter.. Yes, as you may have found out, I've been mixing lots of parts:-)
Checking on a mk2 spare block i installed the mk2 drive gear, which has a part number on it. Installed it at tdc cylinder one firing. Checked the timing dimples, they lined up correctly. At this point, number one firing, they are furthest away from eachother.
Installing the drive gear correctly, slot horizontally, it moved anticlockwise and the slot settled at exactly 2 o' clock/ 8 o' clock. I even measured the angle between a level line through the distributor hole and the slot and it was 30 degrees spot on. So that is correct.
With engine in the same position I now installed the Princess 1800 drive gear, which seems identical but does not have a part number stamped on it. Installing in the same manner, this drive gear turns 10 degrees further anti clockwise, slot ends up at 40 degrees in relation to the straight line.
The big question now: Does this really matter, and can they be interchanged? I mean, it's just a matter of ignition timing/ distributor position, which means with a Princess drive gear the distributor has to be installed at a more retarded position than when using an 1800 drive gear. The firing would still be correct, as long as the point open at the correct time. Or am I missing something?
Actually, I've ordered an electronic ignition set, the same as many of you guys use. Anyway, I want to be totally sure everything else is in order when it comes to ignition, before installing this. I still have an occasional miss at idle, as if the spark misses and the coil still get's hot after some minutes of idling. How are your cars when it comes to coil heat?
Anyway, it's been fine on the road, so have used it without letting the idle irritate me. After looking through my old posts here, (they make a great logbook) I've also put the cylinder head change on hold, as I noticed I had the same problem on the other head. That is fouling of plugs, cutting out at idle etc. Strange if this should happen to two heads.. So, I really want to double check the ignition before I install the electronic kit.
Any feedback welcome!
Regards, Tommy
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Post by threelitre on Nov 8, 2011 22:58:09 GMT
As long as the dizzy housing does not foul the engine block somewhere it will be fine. I once bought an MG Maestro 1600 where the last owner inserted the distributor drive wrong (well, just dropped it in without thinking). In the end I managed to get it to life within 20 minutes: Felt with my fingers through the oil filler cap, when cylinder 4 was firing (OHC engine, R-series). Then I swapped the ignition wires around (needed to be moved one number on from the original position) and finally gave it a timing and it runs fine since....
Regards,
Alexander
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Post by dave1800 on Nov 9, 2011 3:26:48 GMT
Hi Tommy Not sure why you are putting the Princess 1800 distributor drive gear in place other than curiosity  As Alexander says it shouldn't make any difference as long as the distributor doesn't foul anything as it is rotated. I cannot see how it could make any difference to the misfire, only serve to maybe confuse you sometime in the future! Perhaps you could take a temperature reading from your coil body and see how it compares with other members' coils. The misfire with this and the other head could be due to poor valve guides on both, or an air leak or too weak a mixture or something in the HT electrics. As you have exhausted everything already, it seems to point to oil fouling, probably from both the heads. The electronic ignition may be strong enough to overcome the plug fouling and provide a cure to the symptom. Regards David |
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Post by tommydp on Nov 9, 2011 8:19:16 GMT
Hi, and thanks!
I only discovered the difference as I am looking at an engine which I'm planning to fit to the other crab. I then realized I'm not sure if I have the 1800 or Princess drive gear installed in the restored one, as I haven't noticed the difference before now.
But, as you say, it won't matter.
Yes, I agree, the miss is either due to an ignition issue making the plugs foul because of a bad spark, or the other way, the plugs are fouled due to the worn valve guides then giving a faulty spark beause of arcing. There is indeed oil on the plugs after idling and oil finds its way up the spark plug threads, too. A bit strange it doesn't smoke more, at idle for example though.
Anyway, I supose it should not be possible to rock a valve sideways in its guide, and actually clearly see the gap between valve and guide when doing this. I examined one of the spark plugs after a drive. It was then dry but there was a very obvious sign of arcing from the side of the centre electrode to the insulator part.
I am in contact with Peter Burgess, and will send him a head for reconditioning. They were short of used heads. If the valve guides are the cause or not, I guess a professionally rebuilt head would be an advantage anyway.
Looking forward to try the electronic ignition, too!
Regards, Tommy.
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Post by dave1800 on Nov 9, 2011 10:06:05 GMT
Hi Tommy If I am reading Peter's website correctly they do a head without an exchange described as a new casting for £360+VAT. Is it these he is short of? Although a little more expensive than a reconditioed head, you may save the difference on postage. www.mgcars.org.uk/peterburgess/page12.htmlRegards David Hi, and thanks! I am in contact with Peter Burgess, and will send him a head for reconditioning. They were short of used heads. If the valve guides are the cause or not, I guess a professionally rebuilt head would be an advantage anyway. Looking forward to try the electronic ignition, too! Regards, Tommy. |
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Post by tommydp on Nov 9, 2011 10:35:57 GMT
Hi Tommy
We would need to work on one of your own castings we are in very short supply of used core and only sell standard leadfree heads outright on new castings.
Peter
As I understand it, the new heads are those with smaller inlet valves then, as I stated I wanted a 12 H 2709 head with the larger inlet valves. Perhaps I've got it wrong..
Tommy
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Post by dave1800 on Nov 9, 2011 11:15:52 GMT
I guess the outright heads do have the smaller valves as he explicitly mentions the larger valves for some of the other options. I seem to recall that the Princess 1800 had the smaller inlet valves but developed almost identical power to the Landcrab with the larger valves. Did you ever explore how? Do you have the Princess 1800 cam specs? Perhaps it was the distributor drive spindle ;D Regards David Hi Tommy
We would need to work on one of your own castings we are in very short supply of used core and only sell standard leadfree heads outright on new castings.
PeterAs I understand it, the new heads are those with smaller inlet valves then, as I stated I wanted a 12 H 2709 head with the larger inlet valves. Perhaps I've got it wrong.. Tommy |
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Post by tommydp on Nov 9, 2011 16:00:34 GMT
Regarding the heads Burgess supplies, that's what I assumed as well. Reconditioning will be 207 GBP plus postage, quite allright with me.
Princess cam is also 5- 45- 40- 10, but I recall there was a different shape of the lobes between the Princess and 1800 cam. If it was the inlet or exhaust ones I don't remember, but I believe the Princess lobes were wider/ fatter. Another reason not to mix things I suppose. I'm sure my block is a Princess now, but cam, head and everything else is mk 2, so suppose that will be OK.
I'm not sure about the performance of the Princess, but believe they are referrred to as having fewer bhp than the 1800. I will find a head in my barn and have it sent to Burgess. In the meantime I would like to have a scope done, to check out the HT and LT. Not sure who can do this, though.
Regards, Tommy!
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Post by dave1800 on Nov 10, 2011 3:38:00 GMT
Sounds like a good price for reconditioning the head. Are there still any old fashioned garages around there that may have a diagnostic "Sun" or "Crypton" equipment lying around? If not do you have contacts with other teachers who may have access to suitable equipment? regards David Regarding the heads Burgess supplies, that's what I assumed as well. Reconditioning will be 207 GBP plus postage, quite allright with me. In the meantime I would like to have a scope done, to check out the HT and LT. Not sure who can do this, though. Regards, Tommy! |
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Post by kelsham on Nov 10, 2011 8:54:38 GMT
I always use an ignition tester that I bought from Frosts some years ago. It is resembles a pair of calipers, you connect into the plug lead and then vary the spark gap by opening the arms.
The spark can be observed jumping and there is a scale to read the efficiency of the spark being provided. Inexpensive and I have diagnosed HT leads breaking down with it and other faults.
Are you sure the plug fouling is not due to oil passing broken rings? Cant remember if you have done a compression test?
Regards Kels.
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Post by tommydp on Nov 10, 2011 16:15:58 GMT
I always use an ignition tester that I bought from Frosts some years ago. It is resembles a pair of calipers, you connect into the plug lead and then vary the spark gap by opening the arms. The spark can be observed jumping and there is a scale to read the efficiency of the spark being provided. Inexpensive and I have diagnosed HT leads breaking down with it and other faults. Are you sure the plug fouling is not due to oil passing broken rings? Cant remember if you have done a compression test? Regards Kels. Yes, I've got one of those. Shows a healthy spark way up on the green part of the scale. I've never really used anything but a timing light on other cars, both 1800s and others, and have been fine. But then I've never had misfire issues like this before, so would have been great to really rule out the ignition/ electrics through a scope or something. No luck so far, finding someone with the equipment. Block is reconditioned, new pistons, rings etc so doubt oil is coming up that way. Last time I checked, I believe compression was 180 spot on, on all cylinders. Regards, Tommy:-) |
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Post by tommydp on Nov 10, 2011 23:14:49 GMT
LOL! Perhaps this is the solution? around GBP 150. A bit far from me, unfortunately.. Would have been fun to have, every home needs one... :-) Look through the pics until you find "testbenk 60- 70- tallet". www.finn.no/finn/torget/tilsalgs/bilder?finnkode=30827084Has got to be some of these stowed away in some garages which have been around for a while. Regards, Tommy |
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Post by dave1800 on Nov 11, 2011 10:40:05 GMT
Hi Tommy Back in June you said "Installed the sports coil today, and it seems to stay cooler at long periods of idle. It does not get abnormally hot, just "lukewarm"." Have you reverted to another coil or is this one now getting hot too? If this one is now getting hot, the only reasons I can think of are that the coil is failing and passing more current AND/OR that the contact breakers have closed up and so the dwell time has increased, again heating the coil. Overheating of the coil could cause an intermittent misfire. regards David Read more: landcrabs.proboards.com/index.cgi#ixzz1dOoU2jK7and the coil still get's hot after some minutes of idling. How are your cars when it comes to coil heat? |
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Post by tommydp on Nov 11, 2011 22:38:44 GMT
Hi Dave! I still use the sports coil. It don't believe it gets hotter than earlier but I suspect the coil as the miss starts as the coil starts to heat up and engine reaches operating temperature. I only suspect the coil as I've never experienced the coils getting warm at all on these cars, not even luke warm,and I've never had a misfiring issue like this. The car fires instantly, hot or cold. The other crab will idle for ages and the coil stays cool all the time and car idles smooooothly. I've quit swapping coils. It's not down to the coils themselves.
Dwell angle is 60 degrees as it should be, I've even tried setting it to 50, same thing happens. I suppose I'll have to look into electrics and wiring again to see if something is playing up the current to the coil etc. They have started salting the roads here now, so it's put inside the barn awaiting spring anyway.
Only part not changed or checked on electrics is the behind dashboard wiring loom. It charges around 14 Volts at idle, about the same voltage is present at + of coil when running. The miss is more evident when putting a load on the electrics, eg switching headlamps or hrw on. What has crossed my mind is, when I used the Lucas 17 ACR alternator, engine speed would catch up when I disconnected the alternator at idle, engine ran smoother too. The alternators have all been tested and were fine, the chap tested them meant something in the car had to be putting a load on the alternators if they were noisy, flickering etc, as they were all fine. This could make some sense, but what is it. I'm almost tempted to put it back to positive earth again, just to see if it makes a change..
One thing is certain. This car shall meet the spring without misfiring, whatever it takes! AND this summer we'll use it for a holiday!
Regards, Tommy
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Post by dave1800 on Nov 12, 2011 1:05:48 GMT
Hi Tommy I've tested a Lucas type coil here made by Hitachi (12v no series resistor, oil filled and the same size) with the dwell set at 60 degrees and it does reach around 10C above ambient after about 5 minutes. I assume your other cars use points and not electronic ignition? The latter may or may not have electronic dwell control which reduces the effective dwell at idle to just a few degrees so runs cold. It sounds as though your Lucas alternator is breaking down under load ie a leaky diode(s). Try disconnecting the lead from the ignition switch to the coil and replace it temporarily with a wire from the coil direct to the battery +ve terminal. Make a good connection and note that the wire should be capable of carrying 10 amps or more so you don't get any significant voltage drop - so keep it as short as possible. Then see if you still get the effects as you switch on electrical loads. I seem to recall you tried another alternator, did this suffer the same way? If it did then you will need to start the possibly long and tortuous task of finding a problem with the wiring harness. It is most likely going to be a bad connection, but also double check all the earthing points for corrosion or bad connections, including the the block. I've found that temporary bypasses are the easiest way to locate problems, just make sure again that the bypass wire is capable of taking a high load. Also double check the fuse box for intermittent/high resistance. Good luck Regards David Hi Dave! I still use the sports coil. It don't believe it gets hotter than earlier but I suspect the coil as the miss starts as the coil starts to heat up and engine reaches operating temperature. I only suspect the coil as I've never experienced the coils getting warm at all on these cars, not even luke warm,and I've never had a misfiring issue like this. The car fires instantly, hot or cold. The other crab will idle for ages and the coil stays cool all the time and car idles smooooothly. I've quit swapping coils. It's not down to the coils themselves. Dwell angle is 60 degrees as it should be, I've even tried setting it to 50, same thing happens. I suppose I'll have to look into electrics and wiring again to see if something is playing up the current to the coil etc. They have started salting the roads here now, so it's put inside the barn awaiting spring anyway. Only part not changed or checked on electrics is the behind dashboard wiring loom. It charges around 14 Volts at idle, about the same voltage is present at + of coil when running. The miss is more evident when putting a load on the electrics, eg switching headlamps or hrw on. What has crossed my mind is, when I used the Lucas 17 ACR alternator, engine speed would catch up when I disconnected the alternator at idle, engine ran smoother too. The alternators have all been tested and were fine, the chap tested them meant something in the car had to be putting a load on the alternators if they were noisy, flickering etc, as they were all fine. This could make some sense, but what is it. I'm almost tempted to put it back to positive earth again, just to see if it makes a change.. One thing is certain. This car shall meet the spring without misfiring, whatever it takes! AND this summer we'll use it for a holiday! Regards, Tommy |
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