Vacuum leaks, problems, etc.

[Barry Wolk]

My FIL was an engineer and didn't know which end of a screwdriver to use.

I answered part of your question in your introductory post. I'd be looking for vacuum leaks at the carb base, at the intersection of the intake manifold and heads and other numerous vacuum hose connections.

While the engine is barely warmed up, kick it to low idle. Spray carb cleaner at the hose connections and the carb base and intake connections. If the rpm change, that means that the carb cleaner is being sucked into the air/fuel mixture, hence poor performance.

I'd try that before anything else. The next thing would be the Pertronix tune-up as described.

[Barry Wolk]

http://i244.photobucket.com/albums/gg18/barry2952/1%20Mark%20II%20docs/VacuumSchematic.jpg

[Mad Scientist]

A “hot coil” is one that has a higher voltage then the stock one.

A vacuum leak will typically cause an engine to stall or idle poorly. The MKII uses vacuum to run the wipers, antenna, control the flow of coolant to the heater cores, operate the windshield washer and of course the power brakes. Thus there are plenty of potential connections and controls that could be leaky.

If there are no vacuum leaks then make sure the ignition is in good condition and properly timed.

If that’s OK then work on carburetor.

Baring any serious internal mechanical problems that should fix it.

[Ian Cowie]

DL'd your vaccuum schematic and compared that to what I have .... NO vaccuum booster!
Well, it is physically there just not connected to anything. AND, the fuel pump is also there but not connected. It has been bypassed and fed from an electric (stock?) fuel pump (I hear it running when I turn on the key). Sigh .... not sure where to start now. I guess I'll get a vaccuum tester and make sure I get the 20 hg. Antenna works but the wipers do not. I'll check the timing this weekend as well. Sitting still the engine runs nice but certainly stumbles badly when you tickle the throttle.

[Barry Wolk]

The stumbling on acceleration is probably from the piston that give the air/fuel mixture an increased dose on depressing the pedal. You should be able to tell by manually opening the throttle plates to look inside. Moving the linkage should produce two steady streams of fuel into the carb.

What's the idle rpm? It should be 425 when warmed up. If it's set higher it could be masking a vacuum leak.

[Nick DeSpirito]

If you are talking about the vacuum tank booster, it is built into the frame. Follow the vacuum hose coming off the power brake booster. It goes down under and connects to the vacuum tank in the frame.

There were no stock electric fuel pumps. the stock mechanical fuel pump has a double diaphragm. I've seen some (electric) installed on cars, but I think mostly on the V12's of the forties. As far as the wipers, I would examine the hoses and to make sure they are all connected properly and check for leaks. It could be a bad wiper motor if you have vacuum to it. I think the antenna feeds off the same line, so if that is working, it could very well be the motor itself or the vacuum switch on the dash. Do you hear any hissing inside the car?

After I installed the rebuilt carb on my car, I developed a slight hesitation on starting out from a traffic light. Turns out it was the accelerator pump piston. The rebuilder put in a neoprene one and it developed a tear after only a few months. I found this out when my car was in for service over the winter. I was informed that the original was made of leather. They found a guy in FL. that reproduced one for my car. So far, the hesitation is gone.

Someone once suggested that I should install an electric fuel pump with an on/off switch under the dash (I never did) JUST to bring fuel up into the bowl so I wouldn't have to crank the starter so long after the car has been sitting for awhile.

[Ian Cowie]

I'm a tad confused about the vacuum boost.

Nick states:
If you are talking about the vacuum tank booster, it is built into the frame. Follow the vacuum hose coming off the power brake booster. It goes down under and connects to the vacuum tank in the frame.


Barry states:
there is a vacuum booster on top of the fuel pump, driven off the same cam.


So, is there both a vacuum boost (pump) driven off a cam on the engine AND a vacuum booster (tank)?

Where would I find manuals or full schematics for this car?

Thanks all!

[Barry Wolk]

What Nick is describing is a vacuum canister that is built into the frame on the driver's side. Its sole purpose is to provide a back-up vacuum source if your engine stalls. Otherwise it is completely cut off from the vacuum system by a check-valve located on the side of the vacuum booster behind the master cylinder. The valve allows the canister to charge with vacuum and then closes when engine vacuum stops.

I should have used the word vacuum "pump" to describe the device mounted to the top of the fuel pump. One chamber of that assembly provides fuel and the other chamber creates vacuum for the accessories.

Sorry about the terminology.

You should be able to find a Mark II service manual on e-Bay. They are reproductions, but who cares? You also might want to get the LCOC authenticity manual. It also has a lot of information that's useful. Go to lcoc.org to order.

The ultimate manual is the Mark II Encyclopedia. It is chock-full of owner supplied fixes and part cross-references. It is out of print and brings big bucks on e-bay.

[Barry Wolk]

Ian, this may help you restore the original fuel and vacuum pump. It's a pretty straightforward device.

http://i244.photobucket.com/albums/gg18/barry2952/1%20Mark%20II%20docs/Vacuumpump.jpg

[Nick DeSpirito]

I got my Technical Data book directly from a company named Helms. Here is one for sale.

http://cgi.ebay.com/Continental-Mark-II-Technical-Data-Book-1955-325-Pages_W0QQitemZ150361830893QQcmdZViewItemQQptZUS_N onfiction_Book?hash=item23024375ed&_trksid=p3286.c0.m14

No Mark II owner should be without it.

[Shelly Harris]

Definitely a must. That's a good deal. I paid $50 for a reproduction. Only problem is it doesn't include the differences in the 1957.

[Barry Wolk]

Agreed. That's a bargain for that book.

[Barry Wolk]

Maybe these will help you restore the original operation of your wipers.

Here's the piping chart for the wiper circuit.

http://i244.photobucket.com/albums/gg18/barry2952/1%20Mark%20II%20docs/Vacuumchart.jpg

Here's the vacuum tubing for the '56 and '57. You should be able to adapt your '57 carb and distributor to the '56 car.

http://i244.photobucket.com/albums/gg18/barry2952/1%20Mark%20II%20docs/Vacuumpump56.jpg

http://i244.photobucket.com/albums/gg18/barry2952/1%20Mark%20II%20docs/Vacuumchart57.jpg

[Barry Wolk]

This may help, too. This is the exploded view of the vacuum pump. You can see that the lever moves both the vacuum diaphragm on top and the fuel pump diaphragm below.

Looks pretty simple to rebuild. If you need to.

http://i244.photobucket.com/albums/gg18/barry2952/1%20Mark%20II%20docs/Vacuumpump.jpg

[Ian Cowie]

Thanks for the info Nick.
I headed over to eBay and tried to send a note to the seller to see if he would ship to Canada. Apparently you need an eBay logon to do that. Created a logon and then found out I already had one .... signed up 5 years ago. So had to get Customer Service to unlock my dorment account and I was able to send the message. No dice. Tried to submit a bid but was blocked because the seller would not ship outside US. Remembered I had a friend living in NC, so I got her to put in a bid. Got sniped the last 4 seconds so no tech manual for now ... sigh.
I'll have to do a bit of searching on the weeb and find some manuals.
A mechanic friend has a timing light and vacuum gauge so he will bring them up to the lake in a couple of weeks and take a peek at the car for me.
In the meantime I disassembled the washer bottle pump to see why it won't work. Probably too many vacuum leaks. Are parts for the washer available?
Barry - idle is about 600 so you are probably right about hiding vacuum leaks.
There is a vacuum device on the top of the throttle linkage just behind the air cleaner on the driver side. Mine doesn't seem to be connected properly. I'll take a picture tomorrow. NEED a manual and schematics bad!
Thanks again.
Ian

[Barry Wolk]

That's the throttle kick-up for the a/c. It only has vacuum when the air is on.

[Nick DeSpirito]

Yes Ian, like Barry said, that increases the idle when you engage the air conditioning. There should be a wire attached to the top and a vacuum hose on the side. On the threaded shaft coming out of the bottom of the unit, there is a large disc that's threaded on the shaft along with a smaller nut on the bottom to lock it in the adjusted place. There is a fork on the linkage so that that this shaft runs between the tines. When you pull the air conditioning throttle lever forward, this vacuum valve is activated and lifts the fork by means of that disc on the shaft, thus increasing the idle and overcoming the drag (load) the compressor is putting on the engine.

[Ian Cowie]

Kewl ... makes sense when you said "there is a large disc that's threaded on the shaft". I do not have the disc and so when the shaft moves, there is no contact with the fork!
The fun never stops!
So, what sort of disc? Just grab a suitable size washer? Steel? Nylon?

[Barry Wolk]

Actually, a washer and two nuts would work just fine.

[Barry Wolk]

Here's a picture of the assembly on my car.

http://i244.photobucket.com/albums/gg18/barry2952/1%20Mark%20II%20docs/Picture0004.jpg