[gtofreek]

Well, I cleaned up his brass petcocks, and his oil pressure adapter.



Found some Dupli-Color DE1616 Pontiac silver blue metallic engine paint and got it painted. Got the petcocks installed.



Tore the distributor apart to clean it out, and install a BOP composite distributor gear. The distributor looked to have been recently rebuilt by someone. It was all bead blasted. Not a huge fan of bead blasted surfaces on shafts that need to ride in bushings, so I polished up the shaft, and points cam lobes. Now the points rubbing block has a smoother surface to rub on, hopefully reducing wear. Points were like brand new[Blue Streak] so I cleaned up the contacts with some fine sandpaper, and gapped them at .018", which is pretty much where they were. Re-oiled the wick, and re-assembled with assembly lube on the shaft.

[vidguy]

Doesn't look like we'll be able to dyno today. Looking like Tuesday. He's still got a blown alcohol engine on there dealing with carb issues.

Rats...

Thanks for getting the details cleaned up!
I bought that distributor/and Vacuum can from a real nice member here and I did the points install and clean up, etc. Glad you worked it over like you did.
I dont know what the curve is like however.

[gtofreek]

There were 2 shims between the distributor gear, and the body. I re-installed them and installed the gear, and just started the pin in the shaft. Then I checked the gap. It was around .039", but of course the only shims I could find were .035", and I was shooting for .012" as per the BOP instructions. So I installed a 3'rd shim, and had to resort to sanding .008" off the end of the gear on our granite slab, and sand paper, finishing up with worn 400 grit and WD-40. Then upon re-install, I measured .012" end play, so I installed the dowel pin all the way and re-measured the end play, and it was still .012".





Then the intake manifold was hitting the valley pan[what else is new], so I had to bevel the bottom edge of the intake runners, and water crossover.





Now, after beveling the intake, I set it down, and what do you know, it fit perfect! That like never happens! Look at the bolt hole alignment.



And the other side.



Topped it off with some NGK V-Power spark plugs, #8.

[gtofreek]

Originally Posted by vidguy

Rats...

Thanks for getting the details cleaned up!
I bought that distributor/and Vacuum can from a real nice member here and I did the points install and clean up, etc. Glad you worked it over like you did.
I dont know what the curve is like however.

We'll find out, but the springs on it seemed about right.

[HWYSTR455]

Yeah, I bevel aftermarket intakes in those areas, and also clean up the flash in coolant runner, gasket match it, but you have to be careful, you can run out of gasket surface if you go too far.

Nice work on the dizzy by the way!

Stupid pump bolt pads. I don't have a mill, so use a 90 degree grinder. Not much of a cosmetic approach, but gets the job done. I generally don't comment on that, since it's a little Neanderthal. I normally stud the pump too.

.

[gtofreek]

James has a 67 intake for this, so we are just using this intake to run it in. It is bone stock, no gasket match or anything. Just cleaned it up some.

[vidguy]

NICE work on the Poly Gear clearance and the intake. Thanks!

This is an original iron motor and parts build. Even the distributor is the correct piece. I am missing the dual port vacuum advance can, although that is a correct alternate part number non CA can on it now. Original 670 heads (SD Ported), original block, crank, water pump, carb with a temporary (stand-in) intake of the correct vintage, until I get the motor back home and put the original on.

Thanks again Paul.

[Cliff R]

Just a note on shimming distributors and polymer gears. The shaft is .490" on the stock units. Most real hardware stores will have hardened .500" shims in several thickness. I don't like or recommend stacking multiple thin shims in place of using one thick one. I've seen doing this result in one of more of them failing and ending up in the assembly.

The hardware store I use here locally has a nice variety of .500" shims in various thickness, even one in bronze.

It's also not uncommon to have to put aftermarket distributor gears in the lathe and trim them for correct fit and endplay. Most of the BOP gears we've installed here were custom fitted.

We've also ran into issues with the cam gear being rough enough to eat up the Polymer gear very quickly. We started taking the cam to the bead blaster and hitting the gear surface with ultra-fine glass beads, and taking as fine jewelers file to the edge of the teeth to de-bur them.

Another option is to run a bronze gear for a while then switch to the BOP gear, to make sure it's running on smooth gear teeth. It will lead a long life if steps are taken to insure it's gets a good start........Cliff

[Kenth]

Shimming the distributor to tight may locate the gear too low and bind the oil pump shaft causing glitter in oil from oilpump bottom plate.

I have one NOS 1111148 alu-housing with .070" end play and one NOS 1111078 iron-housing with .047" end play.

What did Pontiac knew that BOP doesn´t know?

All i know is that the distributor is pushed up onto the wear shim at all times the engine is running due to the helical gears, leaving the oilpump driveshaft in a nobind location.

Shimming the endplay to .012" in a Pontiac distributor just makes no sense.
I recommend all shimming the gear that tight to check oilpump driveshaft play and wear tracks on distributor/cam gears

JMHO

[Cliff R]

Kenth, if you are shimming the original set-up the guy doing the work just has to look at the contact pattern on the gear and take steps when shimming to keep the contact pattern well centered or off the edges for sure.

I've installed a good many BOP gears, so you are starting from scratch w/o reference, so it may take some additional work including a trip over to the lathe to make sure you are well within range.

I consider .012" the minimum clearance, and have never had any problems sticking to that dimension. It will be fine with a bit more, but .060-.080" like we see with some units that come in here is a bit excessive........Cliff

[gtofreek]

This isn't my first gear install guys. I always make sure the cam gear is de-burred, and smooth. BOP recommended .012" + or - .005" I felt .012" was tight enough, so I went with that. Upon installing it, I held the top of the distributor, where the weights are, to apply pressure while I turned the engine over. The wear pattern on the gear was perfectly centered. Can't ask for more than that. I have only had one BOP gear fail, and it was in a blown alcohols engine that was a take out gear from another engine block. I feel the wear pattern[even though you couldn't see any wear] was located in another spot on the gear between the two engines. Also, the way a blown engine revs instantly, I think it's too abrupt for the poly gear.

[gtofreek]

This distributor had 2 shims in it from the factory. They didn't break, and I see no reason why any would break simply from adding a third. They are being compressed flat. Don't see how that can break them. Plus, this is Tucson, AZ., you can't find squat here. Especially different thickness hard steel shims for distributors, and I wasn't about to spend 3 days hunting all over town to try to find one when I have a bag full of new ones in .035" thickness.

[Cliff R]

Didn't think for a minute that it was your first rodeo with a distributor gear, just providing some good advice based on a doing many hundreds of them.

If you avoid thin shims it will be fine. If all of them are .035 or thicker I'd say they will be OK. It is always better to use one thicker shim vs two or more thin ones. I've seen enough thin shims break up and end up in the assembly to avoid that deal altogether........Cliff

[HWYSTR455]

Isn't the dizzy body one of the main factors of how much clearance they need? Like iron ones you can run tighter, HEIs you should run looser, since they're aluminum?

I use the Moroso shims (#26140), the kit comes with an assortment, and I usually have at least 2 kits so I have a better assortment of thicknesses.

I've never seen an issue with the thin shims, and have run them for many miles, never had one fail.

.

[Cliff R]

I would NOT use any of the thin shims from those kits.

Think for a minute what the distributor drive gear is doing, and you'll quickly see how and why it makes sense to stick with thicker shims.

It drives the oil pump, most are 60# and cold motor oil is very hard to push thru the engine. This puts considerable drive on the distributor gear, and it's a helical cut gear, so will have significant thrust against the bottom of the distributor.

Any thin shims used above the gear can and will break-up and end up in the assembly as they lack the integrity of the thicker shims and can't take the heat. Just mentioning this because we had it happen early on in this business fine tuning shaft end play with shim kits.

Went to thick shims, custom fitting, etc, which may involve trimming the gear in the lathe, and not one single problem since......FWIW......Cliff

[Skip Fix]

Years ago HO Racing had a recurve kit and sold the "better" gears and shims. I forgot what clearance they recommended.

[Kenth]

H.O. Racing wrote:

"Check the the gear to housing end play. This is because the extra clearance will alow the ignition timing to change as the rpm changes so any play over .010" is not acceptable".

I find this information obsolete.

As we all know by now, the distributor gear is pushed up against the wear shim at ALL times the engine is running due to the helical gears and the force from driving the oilpump shaft.
There is NO way the timing will change due to gear to housing end play, simply because there is no endplay while the engine is running.

[gtofreek]

Got the engine over on the dyno. Should be making some pulls tomorrow.

[vidguy]

Thanks Paul. Let's see how it runs.

[gtofreek]

Well, looks like it will be tomorrow for dynoing. It was raining all day, and they got it all hooked up, but it was getting too late.