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General Tech Issues with Distributor--TR4

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KVH

KVH

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Trying to be brief. Really--

I have four distributors: a) an old rusty one I don't want to use; b) a Pertronix about 8 years old; c) a "Race" Distributor from Moss; and d) a vintage 25d from BPNW I had planned to use.

Here's my issue. My old rusty one and the Pertronix both line up the rotor to pushrod tube #1 on TDC compression stroke. Neither the Race nor the vintage BPNW will line up. The lower drive fitting is not in sync with the rotor and distributor cam. In other words, the age-old diagram in the Shop Manual directing that the rotor point to pushrod tube #1 can't apply if I use the Race or BPNW distributor. In both cases the rotor is pointing a good 20 degrees past pushrod tube #1.

I'm thinking this can't be a manufacturing defect in both cases. Would I be correct that it makes no difference that the rotor is not pointing to pushrod #1 so long as, when I'm at TDC of the compression stroke with the distributor gear properly aligned, the points are just beginning to open and the rotor in fact is pointing to the distributor plug wire for Piston #1? My distributor gear and keyway are precisely as shown in the Shop Manual at TDC, so I think I'm probably correct here, but I need to support from the more experienced folks here.

Finally, I have no idea why I bought the "Race" distributor. It's at least 7 years old, and brand new. Is there any reason I should steer away from using it? The Moss material isn't very helpful as to why it's even offered (other than the obvious).

Thanks guys. Looking forward to learning more each day. Marc
 
KVH said:
I'm thinking this can't be a manufacturing defect in both cases. Would I be correct that it makes no difference that the rotor is not pointing to pushrod #1 so long as, when I'm at TDC of the compression stroke with the distributor gear properly aligned, the points are just beginning to open and the rotor in fact is pointing to the distributor plug wire for Piston #1? My distributor gear and keyway are precisely as shown in the Shop Manual at TDC, so I think I'm probably correct here, but I need to support from the more experienced folks here.

Finally, I have no idea why I bought the "Race" distributor. It's at least 7 years old, and brand new. Is there any reason I should steer away from using it? The Moss material isn't very helpful as to why it's even offered (other than the obvious).
Click to expand...

You are correct in thinking the dizzy body position has little to do with timing the ignition. As long as the points position can be set to trigger as the rotor is at #1 'trode on the cap, you're golden. Dwell may be a bit "iffy" but it'll run. Just make sure to document the change for future reference... some folks would be highly confused at encountering the "oddity".
 
I don't know how many teeth are on the dist/oil pump drive gear that engages the cam, but would you get back into line by jumping that gear 1 tooth?
Bob
 
I just looked at the Moss diagram. My suggestion may be more easily said than done, possibly requiring work in the crankcase.
Bob
 
Your 'race' distributor may only have a single base plate which makes it unable to respond to vacuum., but the oscillation factor is eliminated.
 
I don't know why the shop manual makes such a big deal over the distributor's orientation. It really doesn't matter, as long as you have enough clearance to move the thing to time the engine. Mine is about 20 degrees off from the factory position, and it works fine.
 
I have that pump gear about perfect and would shy from moving it. But I don’t know why they’d make a distributor that has a pin fit driving dog out of line with the rotor. It’s as if they felt the Shop Manual “guide” is irrelevant if you plug wire the car with plug 1 where the rotor points at TDC compression.. I can’t see a reason they’d be wrong.
 
Sarastro said:
I don't know why the shop manual makes such a big deal over the distributor's orientation. It really doesn't matter, as long as you have enough clearance to move the thing to time the engine. Mine is about 20 degrees off from the factory position, and it works fine.
Click to expand...
You’re saying your rotor is 20 degrees away from pushrod No. 1? Also Steve, why did I ever buy a Race distributor, and what happens if I use it?
 
You are correct in that you can install the distributor in any position around the clock. You can then time it for the tooth it is aligned with. One or to teeth off will not present a problem, but eventually, if you get to far off the recommended orientation, you may have trouble running wires to and from the unit and/or the vacuum unit will interfere with the engine block.

I would recommend setting a factory unit by the book...and an aftermarket in any way it will fit.
 
Well, yes, that's my point: as long as there is room to move it around as necessary to time the engine, the orientation doesn't matter.

I don't know what a "race distributor" is, or the difference between it and the stock, so I can't really say much about it. I will say, however, that there is a lot of nonsense about improving performance with ignition changes. There just isn't much that can be obtained. In my mind, the main advantage of, say, electronic ignition is reliability and robustness, not so much performance. And, don't get me started on these "40,000 volt sport coils" which are a complete con.
 
I better not get started either, but I'm really put off by all the promotion of "new and improved," and "upgraded," when it's largely hype. I'm also just as put off by the discontinuation of parts replaced by more expensive so-called upgraded ones that really aren't upgraded. I guess the lack of competition is the problem. But having said that, I sure am grateful that I bought a TR4 in 1970 and have had the opportunity to enjoy the heritage and learn the craft needed to keep my later TR4s running. And a big part of that has been this seemingly robust, though apparently slowing, resale/remanufacturing business to keep us all on the roads. I'm thankful for the distributors and suppliers.

As for the tinkering and hobby more generally, I wish I could get things right the first time. I'm continually worrying about some part I've abused, some torque that's off, some lubrication snafu, some clearance that's off, some bearing that might fail, some rod that might go through the block, or some other catastrophic failure. It's hard to accept that not much is really learned well except through experience and prior error. Like when I drove back from Mexico with no antifreeze, figuring "who needs antifreeze" in 110 degree weather, and forgetting that pump lubrication might be an issue, or installing the camshaft bearing before putting that annoying front plate bolt in first, or removing my air cleaners for a more pure test drive, but straight into a heavy sandstorm, or forgetting to install that washer on the chain tensioner post, or forgetting to put the pushrods lifters in before torquing the cylinder head down, or installing the thrust washers backwards, or turning my crankshaft after installing new piston liners but before I'd installed the stops, or installing a new fuel tank with my old (broken) sending unit, or putting the front oil seal in backward, or putting the fan on before the installing the front cross tube, or dropping the carb centering piece down the intake manifold, or twisting the head off the center bolt of the front crank sealing block, or stripping the threads of my fuel pump input flange, or twisting the entire head off my transmission filler plug, or installing my piston rings after 3 had hopped a notch, or installing my engine mounts in the wrong frame holes, or cross-wiring my overdrive. I'll get there one day.
 
Gosh, you do those things too?

I'm comforted by the saying: the way you avoid mistakes is by experience, and the way you get experience is by making mistakes.

Enjoy the journey!
 
I do the same stuff, so I feel better by your confession. On the bright side, we keep busy. I had a Sunbeam Alpine in 1970 and then a tr3 in 1971. Many people do not even think about fixing their cars themselves today, so the learning and mistakes I make are like traveling in a foreign universe today. There is no one to talk to about car problem except for you guys. Heck even back then in the seventies they had Special sports car mechanics and most gas station garages would not touch British stuff.

I do see some young people fixing Japanese engines and they look fragile and fast

steve
 
I used to be a sucker for all the "improved" and "race" parts. The fact is that the factory warranted the entire vehicle for 1 full year. None of the aftermarket suppliers are willing to do that with their parts...and that tells it all. Always go factory if you have the option. Leave the racing mods to the racers.

You mentioned you have a petronix. I have not used a petronix system, but if you do a search, you find there are at least double the threads of problems with petronix than the original point system, and that's considering there are MANY times more points being run than petronix. Just something to think about!?!
 
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