Distributor Question

[OLD SKL 69]

I have a GM HEI distributor in a 70 350. When I was working around the distributor, I noticed that the housing could move side to side by about 1/8 inch. It was tightened down all the way. I then took it out and checked shaft endplay. The shaft is tight in the housing so that is not the problem. Is there some sort of spacer that goes on the part of the distributor that mates against the block? Or is it something else? Any ideas? Thanks.

[Jim's rare 80]

Hi. The only thing I can think of is the rubber o-rings on the destributor. If they have dried out and shrunk, the destributor won't fit snug. Was it easy to pull out? Is the motor running yet?
Jim.

[OLD SKL 69]

There was one rubber O ring on the distributor and yes it was very easy to pull out. The motor does run but it is down on power. Also, I just put an Auto Meter Tach in the car and it works but the rpm needle does not register a steady reading when the rpms are below 1600. It will bounce back and forth fast showing about a 100 rpm difference. So i don't know if that is also indicative of the distributor being somewhat loose and affecting the way the car runs or it is picking up an erratic signal from the dist.

[Oldsguy]

If you have a tach-Dwell meter put that on and monitor how stable the rpm's are, a good tach-dwell meter will be pretty accurate and that would be a good way to verify your tach. It sounds like you have a sloppy distributor though. Maybe try tapping the distributor shaft to see if you can induce any failure, if you can you have a problem. Maybe you could mic another distributor and compare that to yours to see if there is a difference. If they are the same maybe it is the block.

[Jim's rare 80]

Hey. Just curious, What is the distridutor out of. A worn o-ring could cause that much play at the top of the distridutor. Try oldsguys tip on trying tape untill it fits snug, and re-check timing. The distributor should have no play at all when tightened down. I put a used one from an 80 260, into a 73 350, and had to put in a thicker o-ring. let us know. Jim.

[OLD SKL 69]

Thanks for the replies. I don't know where or what engine that distributor came from. It was there when I bought the car. I got a replacement O-ring today and it still had a lot of play. I managed to find an oversize one in the help section and put that in. It seems to be better but still not perfect. I do not have another one to mic it against. I might just buy a whole new distributor. I was looking in Summit at the Pertronix HEI units. Has anyone used them or do you guys have any other recommendations? Thanks.

[Mr. King]

I just installed one of the Pertronix in my 1966 Cutlass with a 330. It made it much easier to start and it seems to run more smooth. I would also spring for performance coil as well.

I'm very happy with it.

[OLD SKL 69]

Was that compared to a stock GM HEI unit or to the points type distributor?

[Mr. King]

That was compaired to the original points distributer.

[soocutlass]

I really do not think that a loose distributer is an issue unless oil is coming out the top. Remember that it is geared off the cam for rotation and if it was an improper distributer it would not mesh with the camshaft. If the Tach wire is loose on the distributer then it would kut out while you are driving. A bouncy tach could indicate a vacuum leak. To check for a vacuum leak I used to use a hand held propane tocrh and turn it on without flame and move around potential leak area of the intake and the RPM of the motor will raise arounbd the leak.

[OLD SKL 69]

Thanks for the vacuum leak tip. I rebuilt the carb today and replaced all carb gaskets. The base gasket was cracked and leaking. The car now starts a lot easier but still is down on power. The vacuum at idle fluctuates between 14 and 15 and actually sounds like it is surging to a small degree. I think my problem lies in the distributor so I ordered a rebuild kit from Summit. After I rebuild it I will post here to let everyone know if that made an improvement. If it didn't, I'll have to open another beer!

[soocutlass]

IF the vacuum is only 14 or 15 i think the timing is little on the retard side as the vacuum should be closer to 18-20. I find the proper timing on an Olds motor is very important. Try to advance the timing are far as possible just before the engine pings or it is to hard to turn over. you will see a big difference in performance. Good luck let me know how you make out.

[OLD SKL 69]

Well, here's what I found out. 1st the loose distributor. I put a new oversized O ring gasket on it and that seemed to fix the distributor wobble. I then took it out and put a new adjustable vacuum advance on it and ignition module. I also shimmed the distributor shaft to fix the excessive end shaft play. (I've rebuilt Chevy small blocks and distributors and thought I would shim the distributor to what I have done in the Chevy's) This was a mistake because when I fired it up the whole distributor was moving and the car would barely run. Apparently, the shaft was bottomed out against the block when I tightened it down and I had taken most of the end play out of it. After fixing that, I put the dist back in and after a minute of running, it just quit. I replaced the module with the original one and it fired right up. The module was either defective or what I had done to the distributor ruined it somehow. I also put in a curve kit to bring in the centrifigal advance a little sooner.

Secondly, I adjusted the timing. My starting point was 10 degrees btdc. Vacuum advance was 0 at idle. The engine ran but had a little surge to the idle. It varied about 100 rpm's every few seconds. Car did not have any real power. I upped the initial timing to 18 degrees btdc. The total vacuum and cent bringing in another 27 by 2000 rpm. It ran well with more power but still not where I would have expected it to be since it is a 70 350 with #6 heads, headers, and flowmaster 2 1/2 exhaust. After driving the car for 15 minutes, the hot light came on. I am guessing because of the initial timing being so far advanced. BTW, no pinging on 87 octane on a 50 degree day.

I have also checked the carb jet size and metering rods to make sure they were within specs for this size engine. The power piston was also functioning so I do not think this is a fuel issue. At this point, I think I need to go into the engine to find out what's wrong since I know someone was already into it.

[Oldsguy]

Well, it might be an issue if your timing creeps because you can't tighten it down solidly. That is how I adjust the timing, loosen the clamp-down bolt just enough to twist the distributor and adjust timing, but I wouldn't dream of leaving it loose for fear the timing would creep over time.

[OLD SKL 69]

I agree with you. I do tighten it down after adjustment but it still is not making the power it should. It seems to come off idle very well but then lays down after 1800 rpm. I will try some other settings to be sure, but I am not optimistic.

As far as the hot light goes, It was the 1st time I ever saw it come on. Of course, without a temperature gauge showing an actual reading, I have no way of knowing it is really overheating or not. The radiator looks good as far as not having any corrosion in it and it flows very well. I may need to buy a cheap gauge to be sure.

[texasred]

CHECK THAT ENDPLAY! Olds have a much larger gap than Chevys. The CCW rotation pulls the gear down to the cam. Not enough endplay and you can fry the cam gear.

As to the carb jetting, talk to 70Wcars. He's a QJet guru.

C.J.

[68/70 Cutlass]

I noticed around where I live I have to keep messing with timing when I get fuel from a different place. Im sure you checked your plugs and made sure the person you got the car from got them for the HEI.