Distributor won't seat on head

R

roughrider

Member
I replaced the head on my '31 and when I put the distributor back in, it won't fully go in leaving 0.090 in. gap between the top of the head and bottom of the distributor. The guide pin lines up and starts, slot on the shaft lines up ok (I know it's offset), but it just won't go down any further. It's a stock distributor and I have made no changes to it. It is a stock head. What am I missing?
thanks.
 
Check that the notch at the bottom on the distributor shaft is engaging in the notch of the mating lower shaft. The lower shaft may also not have engaged at the bottom. Also if you replaced the lower shaft check that it is not too long and the notches are not bent.

Tom Endy
 
Tom,

I haven't replaced the shaft. I feel the notch line up and it drops part way down, just not all the way. I believe it is lined up because once it drops part way, you can't rotate the distributor cam either direction. The guide pin goes down about 40% of the hole depth and the hole is clean.
Stumped...
 
When you removed the distributor.....you might have accidently dislodged the dovetail from the lower end, with the stub shaft possibly being now 180 degree turned, not matching the spline correctly.
 
I have seen the head gasket interfere with the fit of the distributor. The hole was too small for the housing to pass through.
 
Has the head and/or block been resurfaced a lot or in combination with a thinner head gasket? I'd start with J Franklin's suggestion first.
 
I had a similar challenge with one of my engines. The head had been milled down quite a bit, so the standard length distributor shaft held the distributor up off the head about 1/8". I cut down the length of the shaft and increased the depth of the slot to bring the distributor back down on the head.
If you don't want to modify the shaft yourself, perhaps FS Ignitions could make a special length one for you.
Hope this helps.
 
I can also be a buildup of dirt in the drive gear recess--rust flakes scraped off the hole as the shaft is installed.
 
On the same subject, I just had the same problem seating my dist. after installing the head. I think I have it all the way down but I now have an intermittent rattle (not a valve). Could that be the dist shaft is still not seated?
 
Good suggestions from all. I don't know if the used head was milled a lot by the previous owner. I used a Victor copper, head gasket from NAPA, looked pretty thick. My distrib appears to have a one piece shaft. Where do the two piece shafts join together? Can the joint be seen without disassembly?
Is there any chance the ditrib drive raised up when I pulled the distributor out?
It's been 43 years since I started/drove this coupe! It's getting exciting.:eek:
 
If the drive came up it is possible the oil pump is not turning, it is driven with a tang like the dist, but it is centered, not offset like the dist.
The shaft joins at the bottom of dist---and can stick together quite well and seem like 1 piece --the engine I just took apart I thought it had a 1 piece dist, then i put the shaft in the vice and wiggled ---it came apart.

The spring that holds the drive gear in place rusts and gets weak --and sometimes is broken.
 
Still have the old head? Measure the hole from gasket surface to the top, compare to the new head. That may help you narrow the cause.
 
Phred said:
I had a similar challenge with one of my engines. The head had been milled down quite a bit, so the standard length distributor shaft held the distributor up off the head about 1/8". I cut down the length of the shaft and increased the depth of the slot to bring the distributor back down on the head.
If you don't want to modify the shaft yourself, perhaps FS Ignitions could make a special length one for you.
Hope this helps.
Click to expand...

Same thing happened to me. I was lucky to have a machine shop friend who could shorten the shaft for me.

Steve
 
Rough, before you go cutting the shaft, where do you live? There might be a local club near by that has members who would love to help you.They might have another dist and shaft to try in your engine. I think Kirk hit it, and it is possibly dirt or the shaft is not lined up and that is keeping the shaft from seating. Why did you replace the head to begin with? Measure the old head like MikeK said and the new head and see if there is a difference.
 
I do have the old head which has a long crack in the water jacket. I will try to measure the heights of both heads, tho the new one is already installed of course. Will spraying choke cleaner in the hole to clean up the drive create any issues? Of course I will drain the old oil and gunk from this procedure before I try to start it along with some oil in each cylinder before turning the key.
Not just another car, but an adventure.:D
 
Whatever you spray into the dist hole will probably have a good chance to go through the main bearings before it gets to the pan.

If measuring the head thickness doesn't prove that it is the head take off the valve chamber cover --you don't have to take off the manifold, just the carb.
 
Problem SOLVED! Measured both head heights and were very close, so I pulled the valve cover off and the spring that holds the drive down, so I could actually see what was going on:
the distributor drive tang has a "sleeve" around it which contained rust and sludge thus preventing the distributor shaft from fully seating! Cleaned it using a little choke cleaner, paper clip for scraping and Q-tips. Checked the fit with the valve cover still off. Perfect! Problems are so much easier to solve when you can SEE what is going on...
Thanks for all the great suggestions.
Happy in the forests of New Mexico (yes were not all desert).
Altitude 9000 ft
 
One thing for the future, think about getting a two piece distributor shaft. It is made to take the undo wear factor away from the assembly by acting as a U-joint. Thanks for the update>
 
roughrider said:
Problem SOLVED! Measured both head heights and were very close, so I pulled the valve cover off and the spring that holds the drive down, so I could actually see what was going on:
the distributor drive tang has a "sleeve" around it which contained rust and sludge thus preventing the distributor shaft from fully seating! Cleaned it using a little choke cleaner, paper clip for scraping and Q-tips. Checked the fit with the valve cover still off. Perfect! Problems are so much easier to solve when you can SEE what is going on...
Thanks for all the great suggestions.
Happy in the forests of New Mexico (yes were not all desert).
Altitude 9000 ft
Click to expand...

I'm having the same problem with my '29 Sedan. The distributor was really hard to get out. Now that it's out, it wont go back in all the way.
Looks like I will have to pull the valve cover off as well.

Roughrider, thanks for posting your solution!

-Jeremy
 
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