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Distributor Housing/Camshaft Gear

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I think I've asked this before but not sure.

Would it be a big faux pas if I were to CHOP OFF the distributor gear on the end of a camshaft... and then machine a flush plate for the back of the head (with small oil passages I assume)??

I know I have an old housing that I took a hacksaw or belt saw to and just chopped off the distributor insert tube and welded an aluminum plate over it - but it doesn't look that great. I'd rather just get a piece of 1/2" or 3/4" aluminum stock and drill a few holes and machine a few oil passages. I'd like something flush against the back of the head.

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I saw a post on this recently but not sure I saw a definitive reply. I think as long as you figured out what oil passages required (including what the flow should be) it would not be a problem. I assume cam shafts are balanced somehow, not sure if cutting the gear off would introduce unwanted harmonics. I think this would be cool and would consider doing, but on the other hand, why bother?

What I really want is a billet oil distribution block to replace the oil filter head. This would really clean up my dry sump fittings. Korman has them, but they are something like $225 each. I really need my own machine shop!

Fred '74tii & '69GT3

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Actually, if you ditch the distributor, you don't need any oil distribution-

the block on back just gets oil to the cam and distributor gears.

Everything else is handled in the head and via the cam...

Chop away!

t

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Actually, if you ditch the distributor, you don't need any oil distribution-

the block on back just gets oil to the cam and distributor gears.

Everything else is handled in the head and via the cam...

Chop away!

t

Wait a second - so Toby, are you saying that I can just put a flat piece of blank aluminum stock on there and just be done with it?

I have no issues chopping off the gear on the back end of a cam, especially if I can just put a blank block-off plate back there.

Thx.

EDIT: I'm not really doing it for any reason other than to have it be neat and clean - and I'm not there yet... but it would allow the engine to be moved back about an inch without interference with the firewall.

When it's all said and done I don't know that I'll be in the mood to:

+shorten the driveshaft an extra inch

+make a custom transmission mount

+modify the subframe

+possible custom length clutch master slave cyl line

+custom length shifter plate and accessories

(god only knows what else)

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Wouldn't the rear cam bearing leakage oil to the rear have to go somewhere? With the cover, it flows into the distr gear cavity and overflows back to the head internal space. There is also a drilling oil galley in the rear journal that empties into the cavity.

Anybody that has ever seen a rear main knows the leakage oil has to leak both to the front as well as to the rear. Have at a plate and risk burnout of the rear section of the journal.

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I'm looking at a head and the pictured distributor housing and it appears the rear cam journal is oiled from the exhaust-side rocker shaft. After that the exhaust-side oil goes into the main body of the housing to oil the distributor shaft and gear. The intake-side rocker shaft goes only to the oil pressure sensor. It indeed appears that one could simply block off the back of the head with no problem. The oil pressure sensor could be relocated to the oil filter housing, unless you also want to be able to read the head pressure.

jgerock, I see you have the earlier 2-piece heater hose outlet (M36x1.50 to M22X1.50, P/N 11 1 21 250 745 ). I like those because it is easy to eliminate the heater loop by plugging the smaller threaded hole with a 22x1.5mm blanking plug such as the 2002 oil and transmission drain plugs. I can tell you they are hard to get out of an old head though. I ended up welding a big nut on to remove one (successfully, at least!).

EDIT: The rear cam journal has a hole on the side that feeds directly to the return passage to the head, so cam oil need not go through the distributor housing. The second diagonal hole at the bottom of the cam journal does go to the distributor housing, but the gasket blocks it off (see photo above). Even if not blocked, that passage goes to a small cavity at the bottom of the dist. housing that is connected only by a pin hole (can just fit paper clip in it) to the main dist. cavity.

Fred '74tii & '69GT2

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Jim, you might have something-

if oil from the bearing feed (central to the journal) can't leak out the back

of the bearing, there won't be any flow across the back half of the bearing.

It'd pressurize it somewhat- but would there be enough circulation to prevent

the oil from coking up?

I don't think I'd chance it, now that you say that.

So no, don't blank it off, mill a groove so that oil can drain out

of the cavity and back to the head.

As Fred says, there's a port you can use for that. Or you could use

pressurized oil, too- either way, then there'd be some circulation .

Then you'll be good for sure.

t

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Fred -

The cylinder head pictured is from a '72 tii (121 casting) which will be used in my '69 project.

jgerock, I see you have the earlier 2-piece heater hose outlet (M36x1.50 to M22X1.50, P/N 11 1 21 250 745 ). I like those because it is easy to eliminate the heater loop by plugging the smaller threaded hole with a 22x1.5mm blanking plug such as the 2002 oil and transmission drain plugs. I can tell you they are hard to get out of an old head though. I ended up welding a big nut on to remove one (successfully, at least!).

Fred '74tii & '69GT2

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So what's the general opinion about chopping off the gear at the end of the cam?

Good idea or bad idea? I realize it would become a "one off" cam, not able to be used again on a distributor car.

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So what's the general opinion about chopping off the gear at the end of the cam?

Good idea or bad idea? I realize it would become a "one off" cam, not able to be used again on a distributor car.

I don't think it will hurt the cam function to cut it off.

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I don't think it will hurt the cam function to cut it off.

What about balance or introducing some crazy harmonics at a certain RPM? I think you could just chop the end off and be done with it but I don't want to spend the $$ on a decent cam and then ruin it by chopping the cam gear off.

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I suggest calling tech reps at a few quality cam manufacturing companies and see what they say. Do let us know. If they ask why you want to cut the gear off you can just reply "cuz racecar" ... LOL

BTW, if you are going to go through all the trouble to move the engine back you might as well go further back. Will require some firewall mods. There's an E30 club racer in my area with the engine moved back 5 inches--that will certainly make a difference in weight balance and handling. I have looked at dropping my engine and moving it back, but with the stock steering drag link there are clearance problems. The thinner dry sump pan will help a bit, but it is going to have to be a future project for me.

--Fred

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Even if there is someone, who frequents this board, has access to an analysis program and has the talent to apply it, I don't think it would be worth the time to predict with any degree of certainty any upset in balance/torsional harmonics with what you are trying to accomplish.

With all the variations of cam profiles, spring types, etc out there, the cams seem to survive without any big shaft redesign. It's your experiment, so you need to be prepared to cover all the bases or stick your neck out and give it a go. If I were using an expensive cam, I'd leave it alone.

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