Distributor Problems '73 Eldo

[aggie2012]

After weeks of dealing with broken bolts, and ordering parts, I finally have my engine and transmission back in my 73 Eldorado. With a new cam, lifters, and timing set I figured I would be ready to go.....and I would be wrong.

As per the instructions of my old mechanic, I took the coil wire off the distributor cap and cranked for a while so I could build oil pressure. Once that happened I put the wire back and was ready for doing my break in. The son of a gun wouldn't start.

As for the cam, I called Marty over at MTS. Best customer service I've ever had from a parts place. He sent me a factory cam. The receipt in the box said from a 1974 500. Since he is the expert, I trust that this will work in my 73.....or will it?

On my check list of things I checked and double checked: The hole in the cam gear was lined up with the hole on the cam, the dot on the cam gears was a 6 o'clock while the crank gear was at 12 o'clock, the distributor was stabbed to, what I thought was, the #4 firing position.

When I turn the timing mark to 0, the rotor comes around to face number one. This leads me to think I just have a misconception of where #1 is supposed to face at TDC. Does anyone have a picture of where the rotor is supposed to face when #1 is at TDC? I've moved it a tooth in either direction and all it does it pop.....my neighbor even came out thinking I shot off a shot gun lol.

[Dave Shepherd]

Sounds like a basic timing issue, the rotor position only has to be pointed to #1 wire no matter where it is in the cap as long as the rotation and firing order are correct. Pull #1 plug turn the engine over till you feel compression, you should see the balancer mark coming up on tdc, when the marks line up set the rotor to #1 in the cap or rotate the plug wires in the cap to accomplish this. should be good to go if the cam is timed to the crank and the cam is correct for that engine.

[The Tassie Devil(le)]

You could be tying to set the rotor at 180 degrees out.

The only fail-safe way to endure that your distributor is timed correctly is to remove the Right Hand Rocker Cover and as you rotate the crankshaft, observe the Intake Valve Rocker Arm and ensure that the valve is closed before the timing mark at the front pulley is at the static advance of 8 Degrees.

If, when the rockers are rocking open and closed when the timing mark is at the pointer, then you need to turn the crankshaft one more revolution.

As a matter of fact, it doesn't really matter where the rotor is pointing within the cap, so long as the plug wires that are inserted into the cap are corresponding with the rotor button.   But, normally, No. 1 points to around about 10 o'clock, when looking from the front.

Don't forget that distributors in these engines are turning Clockwise, and that the firing order is 1-5-6-3-4-2-7-8, and that the cylinders are Right Bank, 1-3-5-7, and the Left Bank 2-4-6-8

Bruce.

[aggie2012]

I was thinking way too much into this. I focused on where the rotor "should have" been point rather than where my valves were.

The reason I bring up the cam is I read a thread on here that said 73 had a different part number for the cam, but 70,71,72 and 74 were the same.

[TJ Hopland]

Kinda a repeat of what Dave and Bruce said while I was typing but I will leave it just in case there is a useful nugget in here somewhere.   I wonder if the even and odd banks basically being backwards from typical GM's may be the issue?


Cam dot at 6 and crank at 12 does put #4 on the compression stroke so you want the rotor pointing to the terminal with the #4 wire on it.  12 and 12 puts #1 on the compression stroke.    If you are not sure where you are pull the spark plug out of #1 or #4 (your choice, I like to use 4).  Hold your finger over the hole and have someone bump the starter while you watch the timing marks (this is one reason I like 4, you can see the mark easier).  WHen the marks align and you feel air pushing your finger off this is the compression stroke and this is when you want the rotor pointing at that terminal for the wire that is going to that cylinder.  I say terminal, not physically at the cylinder.  One time the marks align you won't feel any air, the other time you should feel it and that is the one you want.

Remember this engine the odd bank is on the right/passenger side.   The left/drivers side is the even bank.    I don't remember where the factory positioned the #1 terminal on the cap.  It really does not matter other than for the length of the wires. 

A 74 cam should be fine.   I believe there was very little difference in the factory cams over the years. 

[The Tassie Devil(le)]

The only time it matters where the distributor body is, is in relation to the room for the vacuum advance, and having sufficient maneuverability to adjust the distributor for retard or advance movement.

Especially when using an HEI Distributor, and dual A/C belts.   Here it is really tight.

Bruce.

[Scot Minesinger]

This happened to me once where a friend brought his 1968 Caddy over to time it.  The timing chain had been replaced and when they put the distributor back it was not in the correct position.  Did not know that when the timing mark lined up with engine cover timing mark that meant cylinder # 1 was firing.  Trouble is the exhaust stroke can be confused with compression stroke on any cylinder.  I think there are sixteen teeth on the distributor gear.  We would insert the distributor and try to start the car.  If it started we would try to time the car.  If the mark did not appear we rotated one tooth and tried again.  On the 15th try we had it.  Took about 10minutes a try.  Now the car runs fantastic.

[35-709]

The '73 cam was kind of an oddball that GM was using to try and cut emissions.  IMO you're better off with the cam Marty sent you which is probably the MTS 5 cam or its near equivalent.  Marty is more than happy to answer your questions on the phone, BTW.

["Cadillac Kid" Greg Surfas 15364]

Geof,
FWIW the '73 cam was "a bit" of a performance cam. Cadillac Engineers were trying to get back some of the performance that the emission controls were giving away. In fact for the '73 Indy pace car, they pulled out the motor, replaced it with a '70 high compression "service" engine, AND installed the '73 cam.
FWIW
Greg Surfas

[TJ Hopland]

One thing I noticed about factory cam specs (at least as much as they publish) is there is a significant overlap.  They don't say how much the valves are open during this period but looking at them it appears that the exhaust is the one that closes fairly quickly most of the way then takes a bit of time to close the last little bit.  We were thinking that maybe it was concern over unleaded gas?  Maybe they thought if they closed them nice and slow they would not wear the seats?   Or that maybe the slightly longer flow time changed the seat temps?   Maybe it was kinda like a 2 stroke where the exhaust flow started to draw the intake charge in?   Who knows.  It didn't look like they did it very long.   None of the replacement cams seem to have that sort of overlap so most people must have felt it was not needed.

[The Tassie Devil(le)]

One thing we all have to consider when comparing factory cam specs to aftermarket specs is that each one uses different standards when measuring their degrees of operation.

Some begin the measurements at initial lift, some at 0.020" of lift, a lot at 0.050".

I notice when reading most Factory Manuals, there is no reference to when the actual lift starts and ends.   Hence there can be some spectacular "performance" specifications.

Bruce.  

[35-709]

Geof,
FWIW the '73 cam was "a bit" of a performance cam. Cadillac Engineers were trying to get back some of the performance that the emission controls were giving away. In fact for the '73 Indy pace car, they pulled out the motor, replaced it with a '70 high compression "service" engine, AND installed the '73 cam.
FWIW
Greg Surfas

Thanks, Greg, for some reason I understood it was the opposite.
Geoff

[aggie2012]

I went back out to the garage this afternoon and put my finger over the #1 plug hole. When my thumb was pushed out I looked down at the rotor and I was 180 degrees out. I turned it around, and what do you know, my 500 came to life. Thank ya'll for pointing me in the right direction!!!

Of course the cars starting brought on a whole host of other issues. Halfway into my cam/lifter break in, I learned my radiator now has a gaping hole in the core. I find this odd since it was fine when I took it out at the start of this project. It just sat up against the wall the duration of my repairs.

The next problem I encountered was the crappy oil pump gasket given to me in the kit blew out. I guess I tore it putting it back together. Does anyone make a thicker one? Installing that oil pump was so much fun I don't want to do it again lol.

Last, but not least, I have oil leaking from the back of the oil pan. It was leaking here before and I was hoping all this work was going to take care of it.

A little frustrating, but I hope to have it ready to go for convertible season....

[Aprules2]

Careful with that oil pump, the replacements are known to fail. Keep an eye on oil pressure at all times. After the first one I have a mechanical gauge I use for break in. Unless its a good pump from one of the caddy performance houses... Like MTS

[aggie2012]

Careful with that oil pump, the replacements are known to fail. Keep an eye on oil pressure at all times. After the first one I have a mechanical gauge I use for break in. Unless its a good pump from one of the caddy performance houses... Like MTS

I don't have a gauge on it, but I think the pump is ok. I had someone watching the underhood for me, and they said I didn't start losing oil until after I cut it off after 15 minutes of running. I'm kind of leaning toward I tore the gasket putting trying to get the oil pump into the bottom of the distributor. Or is there something I missed?

[Scot Minesinger]

The leak in the back of the oil pan is likely the pan gasket or the rear main seal.  If the oil collects in your flywheel cover that is a rear main seal for sure.  You have to drop the pan to fix it.  To do that you have to drop the exhaust Y-pipe, starter, flywheel cover, and center link minimum.  When the pan is off, it takes ten minutes to change out the rear main seal.  A bad seal comes out real easy, and a good or near good is more difficult. 

The oil pump gasket needs to be thin.  You have to spend a lot of time cleaning the original gasket off the block and torque to exact specs after packing it with oil - all per shop manual.

The compression stroke can be confused with the exhaust stroke when looking thru spark plug hole, hence I guess the 180' issue. 

[The Tassie Devil(le)]

Not that easy Scott, as with the Eldorado, the engine HAS to come out to remove the sump.

Don't go for a thicker gasket for the oil pump as you will be decreasing oil pressure to the engine.

But, as you said "I had someone watching the underhood for me, and they said I didn't start losing oil until after I cut it off after 15 minutes of running.", I doubt it being the oil pump gasket, as any problem there would be oil EVERYWHERE, and after 15 minutes of running, the engine would have been drained of oil.

As for the oil leak, I would be climbing into the engine bay and seriously looking at the rear of the Intake Manifold where it meets the block.

Where is the hole in the radiator?   Do you have children?

Bruce.

[Scot Minesinger]

Right, with Eldo you have to remove the engine - lost track of the FWD/RWD part of the equation

[aggie2012]

My biggest worry right now is that I'm going to have to pull this engine again.

That was my train of thought as well. The oil looks like it's coming from where those two surfaces come together judging where the major puddle is.

The hole in the radiator is on the bottom right hand side of the front. Haha no children. I must ask why you ask lol

[The Tassie Devil(le)]

The hole in the radiator is on the bottom right hand side of the front. Haha no children. I must ask why you ask lol

Children have been known to accidentally damage things and then not say anything

But, check everywhere to try and locate the oil leak at the back before proceeding further.

Bruce.