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     Brian Vogel Grand Master Username: guyslp Post Number: 1407 Registered: 6-2009 |
I am really hoping that I may be able to get back to working on SRH33576 in the near future and get the distributor borrowed from LRK37110 moved back to its rightful home. Since the Christmas FTP and subsequent diagnosis of ignition module failure a number of complicating factors in life have arisen that have slowed any work to a crawl. Not all of these have disappeared. Another participant on these forums was kind enough to supply me with a Mallory Unilite distributor that is made specifically for RR/Bentley V8 engines of the SY era. In order to install that I would have to have the original coupling from the Lucas distributor removed and transferred by a machine shop. Then I would have to set up the engine timing entirely from scratch. I have attached the instructions for for attaching the drive coupling to the distributor itself for reference. I know that the Pertronix LU-281 electronic ignition is nearly a "drop in" replacement for the original Lucas ignition and recent traffic regarding doing this on rollsroyceforums.com makes it seem, provided you position the pick-up on the new ignition in very close to the same location as the original, that it's just a matter of fine tuning the timing once that's been done. Right now I need to consider what will require the least amount of time, frustration, and "hard learning" on my part. Never having replaced either a distributor as a whole item or installed a replacement electronic ignition module I could be thinking that either one of these directions is either far more complicated, or far simpler, than it really is. I'm sure that there are those here who've replaced the electronic ignition module alone and suspect that there are also those who've gone the entire distributor route (if not on a RR/Bentley then on another car with a V8 engine). I'm looking for input as to what makes the most sense to keep me sane and to minimize the number of unexpected "gotcha!"s in this repair. Input is appreciated. Brian
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| Geoff Wootton Grand Master Username: dounraey Post Number: 780 Registered: 5-2012 |
Hi Brian Here are my first thoughts; hopefully a discussion will ensue to help you make your decision on which way to go. If that Mallory is a new unit then I would be very tempted to fit it. I realize the machine shop costs would probably be the same as a new Pertronix unit, but for the same cost you have a brand new distributor. If you have a drill press you could consider transferring the drive coupling yourself, however it is a precision job. As for timing, in my view, that is a total non issue. The text book method is to simply get the A1 cylinder at TDC on the compression stroke and insert the HT leads such that the A1 lead is closest to the rotor position The others are fitted in the correct firing order relative to the A1 lead. Once you have carried out this coarse timing, the fine tuning can be carried out with a timing light. Since it is difficult to rotate the engine to find TDC on these cars I'd probably set the new distributor up relative to how the original was positioned. I don't think setting the timing should be a factor in your decision. Geoff | |||
| Robert Noel Reddington Prolific User Username: bob_uk Post Number: 154 Registered: 5-2015 |
Fitting a new module is straight forward and 30 mins max. If fitting an entirely new pick up. Then the pick up must fire when the rotor arm is in line with the dizzy cap segment. The width of the rotor allows for some lee way. I like to position the rotor at A1 then a shallow junior hack saw cut to mark the dizzy Bosch dizzys are like this. I have found that Bosch dizzys put the engine at tdc and rotor arm centre on the line and the engine starts. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 1408 Registered: 6-2009 |
Geoff, The Mallory distributor is brand spanking new and my local machine shop gave me a guesstimate of approximately $25-30 to pop the coupling off of the old distributor and on to the Mallory. I would far sooner have someone else who has precision equipment, a really good drill press, and a press to pop out the securing pin do this step. For the price I was quoted it's a no brainer. My main concern is about getting the A1 cylinder to TDC and knowing that I've actually succeeded in doing that. I presume at the moment I could possibly do that by simply cranking the engine until the rotor arm on the existing distributor is pointing at the A1 lead position. When I was doing my early testing it didn't seem to rotate all that quickly when cranking the engine. Bob, I don't know what the distinction is that you're making between "fitting a new module" and "fitting an entirely new pick up." Since the pick up is part and parcel of the module those two activities are one and the same as far as I can see. Brian | |||
| Robert Noel Reddington Prolific User Username: bob_uk Post Number: 155 Registered: 5-2015 |
The pick up whether part of the module or not must be positioned correctly. If replacing like for like then the exsisting fixing will automatically postion the pick up in the correct positiom. But if fitting a pick up /module that is different then care must be taken that when the pick up fires the rotor is aligned with a dizzy cap segment. Normally a non original module will come with fitting instructions snd some sort of adaptor plate. Some may require drilling of the dizzy base plate. There is a bi directional programable dizzy with no mechanical advance. It has a usb port. I just can't remember where I saw it. I would for the sake of originality fixed the orginal dizzy. They are well made. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 1409 Registered: 6-2009 |
Bob, Thanks for the clarification. I thought I had been clear as well with presenting the two options I have, and a Pertronix module is not a Lucas Opus module, so one would have to position the pick-up correctly. I know that the Pertronix base plate allows it to be pivoted such that the pick-up can be positioned correctly. Though SRH33576 has the original distributor, it long ago had a blue Range-Rover distributor cap fitted. This car had been radically modified before ever coming into my possession. It was originally a RHD home market car that was converted to LHD at some point in its life. That involved moving a bunch of things while leaving a bunch of others in their original positions. It always makes it interesting to find the occasional component when I forget this and am looking for where it should be on a LHD car rather than RHD. Originality is just really not a consideration for SRH33576. I'm more concerned with originality for LRK37110, but refuse to be a slave to "a foolish consistency" such as rejecting US style hose clamps, using only old-style Lucas relays, etc. It's a car, not a historical document. Brian | |||
| Geoff Wootton Grand Master Username: dounraey Post Number: 781 Registered: 5-2012 |
Brian I agree Brian, it's a no brainer. Here's a thing - On the SY2 the slot in the drive coupling is offset so the distributor can only be inserted in one position. An important relationship is the relative position of the rotor arm to the drive coupling. If the machine shop drill the hole through the shaft of the Mallory so this relationship is upheld, then you will be able to put the new distributor back on without concerning yourself about TDC. To clarify, if the slot in the coupling is, say, at 4'oclock when viewed from the end of the distributor and the rotor arm is at, say, 2 o'clock, then if the machine shop line the coupling up in exactly the same way and then drill the hole, the distributors will be identical. You can then fit the Mallory and start the engine ready for fine tuning the timing with a timing light. Geoff | |||
| Randy Roberson Grand Master Username: wascator Post Number: 451 Registered: 5-2009 |
Brian, I had to turn the engine in SRH9391 so I used a strap wrench on the water pump pulley and it worked fine. it does not have an air pump and it may be harder with one; you can remove an air pump pretty quickly. The wrench had a canvas strap which did not scratch anything. You can remove A1 plug and while barring, either put your finger over the plug hole or leave the plug in but loose enough to leak compression so you can hear it; when compression is forcing air out you are on the right stroke; use the timing marks on the crank pulley to get it spotted just right. | |||
| Philip Sproston Experienced User Username: phil2025 Post Number: 16 Registered: 7-2006 |
Brain Here in Australia we have a new replacement distributor and coil what fit all RR V8 motors. It uses Bosch internal parts an has been fitted to many cars. One sprit with 320000 kl is now getting 10% better fuel consumption. Starts better and does not foul plugs. All that is needed is the old drive gear to set the distributor up in the testing machine to synchronise. Bob Chapman and I both sell these units | |||
| Geoff Wootton Grand Master Username: dounraey Post Number: 783 Registered: 5-2012 |
Randy Brilliant. I have always found it impossible to turn these engines. Great idea. I will try it next time I need to rotate the crank. Another method I have read about to check that the engine is on the compression stroke is to fit a length of clean flexible tubing into the A1 spark plug hole. Blow down the tube and if you feel resistance you are on the compression stroke, no resistance, the exhaust stroke (since the exhaust valve is open). Geoff | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 1410 Registered: 6-2009 |
Thanks to all for your insights. I cannot tell you how much I appreciate them. This is precisely what a forum like this is supposed to be about, and you all have come through again! If anyone's got more to offer please do so, since WTMI [Way Too Much Information] never really applies when it comes to sharing "been there, done that" experience. Brian | |||
| Geoff Wootton Grand Master Username: dounraey Post Number: 784 Registered: 5-2012 |
I agree with what Brian has just said. I never think of this forum as being for straight "questions and answers" as so often there is not one single correct answer. I think of it more of a brainstorming session from which the person asking the original question can decide on the process or procedures best suited to his needs. The benefit for the others is so much good information drops out in the course of the discussion. Geoff | |||
| David Lacey Experienced User Username: dlacey Post Number: 47 Registered: 11-2010 |
Hi Brian, since nothing is disturbed you can use the pulley or flywheel markings to set TDC, as mentioned here a simple hose screwed in to No1 will differentiate the compression stroke from the exhaust stroke. Thats easier than taking off a cam cover to observe valves. If you fit the kit to the existing dizzy, the topic that Bob mentions about "phasing" the low tension pickup with the HT rotor arm position should not be underestimated. I had problems here on a Jag V12 with a Crane ignition kit. One trick is to drill a large hole in an old dizzy cap in front of No1 post so that once its running you can shine your timing light in and check that the rotor arm is pointing at the right post as you rev/advance the ignition. Phase it staticly with the rotor arm trailing edge aligned with No1, so that the leading edge will be aligned when its fully vacuum advanced. | |||
| Robert Noel Reddington Prolific User Username: bob_uk Post Number: 158 Registered: 5-2015 |
Phasing is a good way of describing what I meant. The more cylinders there is the more important phasing becomes. I can imagine a rotor arm being between two cap segments when the pick up fires and the spark going which ever way it wants. Pop bang fart. I like the idea of a cap with a hole to check or one could saw a side bit out. I agree in part with Brians comment its a car not an histotical document. One has to be sensible. My car is a daily driver ( except I am not driving yet) If relay goes and I don't have a pucker Lucas one. Then fitting a £4 modern one isn't exactly modifying the car and it's easily reversible. The same applies to the dizzy its simply plug in the bolted down. 30 mins and its back to original. Where it goes to far is when Gas Monkeys bugger about with a Spirit. They pumped the brake pedal to bleed the brakes. Arron Kaufman is obviously a good mechanic. But saying he doesn't want to understand the brakes is not proper for a good mechanic. Back to dizzys. Recently in these hallowed pages was a posting about converting a SY1 to electronic. I think the bits was 60 quid. Or 3 sets of points. I thought nice and cheap. Basically the SS2 dizzy is a SS1 dizzy modified by Lucas. I have mucked about with electronic dizzy. The way they work is so simple. The pick up can be separate and electronic switch fitted out side the dizzy. This gives a huge range of options. I leanrt a lot by mounting a Ford dizzy in my lathe. I ran it with the cap off. For instance the air gap. If set to close the pickup could hit the rotating bit. I found the pickup could be over twice the distance. The signal fades a bit but there's enough to fire the out put transistors. So the gap isnt that important near enough is good enough. Its a car not a historical document I must remember that. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 1411 Registered: 6-2009 |
What would make infinite sense is to either use a clear plastic for the entire distributor cap or at least for a "sandwich band" that would allow one to see the position of the rotor arm inside the cap. You can't tell me that there's anything mystical about the plastic on radiator caps, as they come in virtually any color you can name these days. Of course, by and large distributors like the ones we're discussing are themselves things of the past. Still there are enough around and replacement caps are still made and sold. Brian P.S. to Bob: It really does astound me how many people forget that only a very few examples of "as issued from the factory" are needed for museum purposes. Those who drive their cars tend to do what's necessary to keep them such that they can continue to be driven, including making modifications to things like electronic ignition, commonly available relays, use of modern "toothed" belts, radial tires, etc. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 1412 Registered: 6-2009 |
For those who are curious, I couldn't attach the Mallory Distributor Installation Instructions yesterday because the PDF was too large. It's now accessible via the link given. Though this distributor is now out of production it is still available (or was recently, anyway) as NOS. The part number doesn't show up well in the photos and is 4711701H. As you will see from the photos it is an optical system and the distributor cap fits on only one way and is keyed with a tiny cut-out that matches up to the post directly above the lines going in to the housing.       Brian | |||
| Robert Noel Reddington Prolific User Username: bob_uk Post Number: 161 Registered: 5-2015 |
There is a train of thought in the old car world that modifications become part of the cars history. My dad fitted that extra ash tray 50 years ago sort of thing. Patina. I have noticed that more and more old car people are starting to understand patina. The dizzy certainty looks the part. Mallory make quality stuff. Rhubarb crumble and custard for tea is was smashing. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 1416 Registered: 6-2009 |
Today I decided that since I have three distributors here, two of which are original, it gave me an ideal opportunity to do some careful comparisons. First I took the distributor that's extracted from SRH33576 and held it over the one currently installed, aligning the vacuum advance up so that all things "are equal." Since someone who worked on the car previously marked the respective cylinder wires, I know precisely which location on the distributor cap is the A1 lead. I then rotated the spindle on the "comparison" Lucas distributor such that the rotor arm was aimed at the same location and marked A1 on that distributor. (I also bothered to stick a piece of tape with the A1 position noted on the distributor currently installed). As it happens (no surprise there) when the rotor arm points to the A1 position one of the ferrite bars is dead center opposite the pick-up in the distributor. I then did something similar using the Mallory distributor with the extracted distributor as my reference point. Lo and behold!, when their respective vacuum advances are lined up, and the spindle is positioned on the Mallory distributor such that it points to the same (or very close to it) A1 position on its cap, it so happens that one of the optical slits is dead center on its optical pick-up!! If I can get the machine shop to put the coupling on to the spindle such that the spring steel "grip" in precisely (or nearly precisely) the same orientation to the rotor arm as it is in the Lucas distributor I will essentially have a "drop in and set timing" situation. Or at least I think I will. Provided I've got everything set up with this sort of congruence it seems to me that I don't even have to worry about getting the engine with the A1 cylinder at TDC of the compression stroke. If necessary, please blow a big hole in my theory, as I don't want to set myself up for a massive frustration or failure if I go this route. Brian | |||
| David Lacey Experienced User Username: dlacey Post Number: 50 Registered: 11-2010 |
Hi Brian, I am sure with the 'mechanical alignment' you discuss it will be close enough to get the engine to start/run, but you'll still need to fine-tune the timing with a strobe light. BTW, transparent Dizzy caps do exist:http://www.summitracing.com/int/search/product-line/mr-gasket-clear-distributor-caps but maybe not for the RR (enough bling already) | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 1417 Registered: 6-2009 |
David, I'm aware that I will need to fine tune the timing, hence my "and set timing" comment. So far the consensus is that provided I can get everything set up as I'd described I should have a drop-it-in-then-fine-tune-timing situation. Of course I realize that I need to know the position of the rotor arm on the currently installed distributor before I put the new one in so that I don't have a 180° off situation. I presumed that clear distributor caps must exist, I'm just surprised they haven't become more common. It would be quite handy to be able to observe what's happening in action during diagnoses. It would also be quite the "light show" to watch a distributor in action after nightfall. Brian |
Distributor Drive Coupling Installation Instructions