CaliforniaSpecial.com -- Message Boards -- 1968 California Special Limited Edition Ford Mustang GT/CS
D I S C U S S I O N . F O R U M
COMMUNITY
1968 GT/CS & HCS
2007+ GT/CS
1966-1967 HCS

Vote!

Old 09/01/2015, 07:16 PM   #1
66hcs-conv
My Car Details
 
66hcs-conv's Avatar
 
66 HCS-conv, Columbine blue & 2001 Cobra conv

Location: Loveland, Colorado
Joined: Apr 07
Posts: 301

My Garage
%^&#*! wont start when hot

Hi all,

After having the engine (289) and carb (2bbl) rebuilt, the '66 still won't start after driving, and getting the engine warm. If I wait 2-3 hours it will start, but waiting 15-30 minutes it will not start, unless I squirt some starting fluid in the carb. The auto chock is pulled completely off - no chock being applied.

The timing is advanced about 4 degrees over the 6 degrees BTDC. Would moving the timing back to the stock 6 degrees help?

I am using 91 octane, and I am at 5000 feet altitude. I have replaced the metal carb spacer with a fiber one.

This thing is wearing me out.

I would appreciate your thoughts

Thanks, Dave

Last edited by 66hcs-conv; 09/01/2015 at 07:36 PM..

If confusion is a destination.....we have arrived.
66hcs-conv is offline   Reply With Quote
Old 09/01/2015, 08:35 PM   #2
robert campbell
My Car Details
 

Location: Bremerton Washington
Joined: Apr 07
Posts: 3,672

My Garage
Dave,
Hard to say, but here are my thoughts. First I hope you do not take offense, but do you know how to start and old 60's engine? I explain this to every customer through my door. It ain't no Camry/Honda.

When cold your owners manual tells you to depress the accelerator fully to the floor and release. And not touch it again. If you flutter the accelerator upon starting it releases the choke from the top step of the fast idle and defeats the choke sequence. This sets the choke and inserts a squirt of raw fuel into the engine. This provides a rich mixture to start the car and sets the choke on the top step of the fast idle cam. This allows for the car to start cold and warm up.

Now when hot. Your owners manual tells you to depress the accelerator to 1/4 throttle opening and hold it. HOLD IT and do not release. Try to start it with a 10 second burst of the throttle. DO NOT release the throttle if it does not start. Try again. If you release the throttle and then open it again it pumps more raw fuel into the engine. A hot engine does not want this. If you pump the throttle it just exacerbates a hot engine by further flooding it.

Now to the carb. You indicate it is rebuilt, but if the float setting is too high or the rebuilder used a nytrophol (black plastic float) it may have too high a float level in the carb. This allows the gas in a hot engine to "percolate" out of the carb and drain raw gas into the engine. Most prevalent after a hot start try after about 10 to 15 minutes of sitting. This is the worst time to start a hot engine with a high float level.

I always use a brass float and by default always set the float level just a bit low. If the engine does not run excessively hot, most cars I work on start with just a touch of the key when hot with no throttle opening.

As for timing, you indicate you are about at 10 degrees initial timing. In my experience that is about right. Do you have a dual diaphragm vacuum advance? These can play havoc a bit with the 289/302. I have more success with the single diaphragm set up. The new ones are adjustable and allow me to sneak up on 12 to 14 degrees of initial advance by reducing the amount of vacuum advance. You can put an allyn wrench in the tube you attach the vacuum hose to and reduce the amount of vacuum advance.

Rob
robert campbell is offline   Reply With Quote
Old 09/02/2015, 05:22 AM   #3
Ruppstang
 
Ruppstang's Avatar
 

Location: Weeping Water, NE.
Joined: May 09
Posts: 2,378

My Garage
Good advice Doc.

Follow HCS restoration at http://68hcs.weebly.com
Ruppstang is offline   Reply With Quote
Old 09/02/2015, 10:11 AM   #4
66hcs-conv
My Car Details
 
66hcs-conv's Avatar
 
66 HCS-conv, Columbine blue & 2001 Cobra conv

Location: Loveland, Colorado
Joined: Apr 07
Posts: 301

My Garage
Rob, no worries. I've been driving 6 & 8 cyl Mustangs since my first one in 1966. Never had one that is as difficult to start as this one when hot.

I have been "cracking" the throttle at hot start, being careful not to press so hard that the accelerator pump pumps more gas in the carb.

The float is brass, and I don't hear anything sloshing around when I shake it.
I will check the level & lower it a little. If the lower fuel level doesn't help, I'll try bringing back the timing.

I have fabricated a round flat piece of aluminium to try as a substitute for the round air cleaner top. It is the same diameter as the air cleaner, so maybe it will allow the hot air to escape from around the air cleaner.

I am using a 40 KV coil, that is mounted to the front of the engine. Wondering if the coil is breaking down when hot. Maybe a different, more voltage coil would help?

Thanks, Dave

If confusion is a destination.....we have arrived.
66hcs-conv is offline   Reply With Quote
Old 09/02/2015, 11:01 AM   #5
Mosesatm
 
Mosesatm's Avatar
 

Location: Spokane, Washington
Joined: Jan 05
Posts: 7,382

Are you running points or electronic ignition?
Mosesatm is offline   Reply With Quote
Old 09/02/2015, 02:49 PM   #6
66hcs-conv
My Car Details
 
66hcs-conv's Avatar
 
66 HCS-conv, Columbine blue & 2001 Cobra conv

Location: Loveland, Colorado
Joined: Apr 07
Posts: 301

My Garage
Quote:
Originally Posted by Mosesatm View Post
Are you running points or electronic ignition?
Petronix electronic and the 40K volt Petronix coil.

If confusion is a destination.....we have arrived.
66hcs-conv is offline   Reply With Quote
Old 09/02/2015, 05:00 PM   #7
Mosesatm
 
Mosesatm's Avatar
 

Location: Spokane, Washington
Joined: Jan 05
Posts: 7,382

Did you bypass the resistor wire? Do you have 14 volts at the coil? One of my previous cars with Pertronix wouldn't start when it was hot and the problem ended up being inadequate voltage going to the coil.

Last edited by Mosesatm; 09/02/2015 at 05:16 PM..
Mosesatm is offline   Reply With Quote
Old 09/02/2015, 07:52 PM   #8
rvrtrash
 
rvrtrash's Avatar
 
So many cars, so little time!

Location: Post Falls, Id.
Joined: Apr 03
Posts: 3,445

My Garage
Here's a couple of things to consider.
1) Arlie is correct on aftermarket coils possibly needing the full 12V, however, in the "Start" position, 12V would be present. It drops when you release the key to the "Run" position. Your coil could have degraded if it's been in there a while without the full 12V run voltage.
2) Coils (basically a transformer) can break down with heat, but it's usually a problem with high performance engines that generate more heat, not so much with standard engines. A common fix is to move the coil to the shock tower, away from direct engine heat.
3) You could have a bad carb. If something is warped, worn, or a mating surface damaged, you could have a fuel leak into the intake. This not only floods the engine, but leaves the carb dry. I had a 428 Cobra Jet carb once that you could actually see fuel dripping into the intake after the car was shut off.

I would start by making sure you have the right voltage to the coil and checking the carb. If it's an Autolite, you can run the engine up to temp, wait 15-30 minutes and take the top of the carb off to see if the fuel bowl is draining down.

Steve

The wannabe formerly known as an owner.
rvrtrash is offline   Reply With Quote
Old 09/02/2015, 08:24 PM   #9
66hcs-conv
My Car Details
 
66hcs-conv's Avatar
 
66 HCS-conv, Columbine blue & 2001 Cobra conv

Location: Loveland, Colorado
Joined: Apr 07
Posts: 301

My Garage
Arlie & Steve,

I have not by passed the resister wire, and I will certainly check the voltage tomorrow AM, along with looking at the carb.

Thanks guys, Dave

If confusion is a destination.....we have arrived.
66hcs-conv is offline   Reply With Quote
Old 09/02/2015, 09:30 PM   #10
robert campbell
My Car Details
 

Location: Bremerton Washington
Joined: Apr 07
Posts: 3,672

My Garage
Dave,
Thought I posted earlier but it did not show up. If you can start the car with starter fluid when hot, then it is not an ignition issue IMO. It is either excessive heat causing percolation of gas out of the carb causing flooding. Or it is a high float level that is susceptible to flooding when hot.

My guess is not an ignition issue. My guess is if you open the throttle to well over half way and hold it when hot it might start when hot. A sure sign of excessive fuel in the carb and intake. Usually present after about 10 to 15 minutes after shut down when hot.

Rob
robert campbell is offline   Reply With Quote
Old 09/03/2015, 07:51 AM   #11
66hcs-conv
My Car Details
 
66hcs-conv's Avatar
 
66 HCS-conv, Columbine blue & 2001 Cobra conv

Location: Loveland, Colorado
Joined: Apr 07
Posts: 301

My Garage
RATS !

Checked the "run" voltage at the coil and it is 12.68 jolts. So apparently I have
(or somebody has) bypassed the resistor wire. Shoot, thought we had the solution.

I did notice with the engine shut off, that the carb throttle plates (the ones at the very bottom of the carb) are completely closed, Shouldn't those plates be just a little bit open? I can't find any specs in the shop manual that calls for an opening.

Thanks, Dave

If confusion is a destination.....we have arrived.
66hcs-conv is offline   Reply With Quote
Old 09/03/2015, 08:48 AM   #12
robert campbell
My Car Details
 

Location: Bremerton Washington
Joined: Apr 07
Posts: 3,672

My Garage
Dave,
It is very hard to see the gap for the throttle plates. They are adjusted by the "curb idle" screw when at full operating temperature. The relationship between the throttle plates and the transfer slots or transfer holes in the throttle body is critical. First you need a hot engine with no vacuum leaks.

I preset a 2100 with the idle mixture screws out two turns. On a good engine this is a good starting point. Get the engine to full temp. I start by slowing the curb idle down to around 600 rpm. If the engine will run then you can experiment with the idle mixture screws. If it won't idle at this speed you may need to open or close each screw 1/2 turn.

Once you get the engine to idle slow at 600 rpm then you can fine adjust. Try opening or closing the idle mixture screws 1/2 turn. If when adjusting the first screw the engine speed up, then do the same with the other screw. It should speed up even more. Next slow the engine back down with the curb idle screw. Then try adjusting the idle mixture screws again. If you can speed the engine up even more then do it a slow it down by turning on the curb idle.

What you are trying to achieve is the best idle speed with the mixture screws. If you have a vacuum gauge it is even better. You are adjusting the idle mixture screws for the highest vacuum you can achieve. Normally on a stock 289 it is around 16 to 18 inches at hot slow idle. You should look for a vacuum connection on the block in the back of your intake. You can unplug your vacuum modulator and use its port for the vacuum gauge.

Now if you decide to advance or retard the ignition timing you need to do the above all over. I like to go to at least 10 or 12 BTDC. I follow this by adjusting the vacuum advance to reduce its curve just a bit. This seems to work great on all stock 289's and 302's that come through my shop.

I will post a pic of the newer vacuum advance that you can adjust.

Rob

Now the other
robert campbell is offline   Reply With Quote
Old 09/03/2015, 01:24 PM   #13
66hcs-conv
My Car Details
 
66hcs-conv's Avatar
 
66 HCS-conv, Columbine blue & 2001 Cobra conv

Location: Loveland, Colorado
Joined: Apr 07
Posts: 301

My Garage
I lowered the carb fuel level to 7/8 below the top of the carb, per the shop manual. It was about 1/8 to high. I noticed I still had the flat land jets (#50) in the carb, so I installed two #48's - I know, has nothing to do with the starting problem.

Adjusted the mixture screws, using a vacuum gauge. Left the timing at 10 degrees advance.

Went for a ride. let it sit, and it started! Maybe I got it fixed.

I took the top off the carb, and the fuel is still the correct level, but man was it bubbling!

Since the engine rebuild this thing runs hot - 230 according to the radiator cap/temp gauge. Probably doesn't help the starting situation.

Thanks, Dave

If confusion is a destination.....we have arrived.
66hcs-conv is offline   Reply With Quote
Old 09/03/2015, 02:18 PM   #14
66hcs-conv
My Car Details
 
66hcs-conv's Avatar
 
66 HCS-conv, Columbine blue & 2001 Cobra conv

Location: Loveland, Colorado
Joined: Apr 07
Posts: 301

My Garage
So after about a 45 minute wait I noticed the fuel lever in the carb bowl has gone down 3/4 of a inch! It is leaking out some where.

Anybody know about the inner passages in the &*&!^&# carb, and how to stop the drain?

Thanks, Dave

If confusion is a destination.....we have arrived.
66hcs-conv is offline   Reply With Quote
Old 09/03/2015, 08:00 PM   #15
p51
My Car Details
 
p51's Avatar
 
Carpe Diem

Location: NorCal
Joined: Aug 05
Posts: 924

Quote:
Originally Posted by 66hcs-conv View Post
RATS !

Checked the "run" voltage at the coil and it is 12.68 jolts. So apparently I have
(or somebody has) bypassed the resistor wire. Shoot, thought we had the solution.
I assume that means that you are turning the key to "run" without the engine actually running and measuring the voltage at the coil primary input...
If that is the way you are measuring you may still have the resistor in the wire leading from the ignition to coil. If the points (or Pertronix) happen to be open you are measuring an open circuit at the coil. With an open circuit no current is being drawn which means there will be no voltage drop regardless of whether there is a resistor or not. In that case you would see the battery voltage. Now if you close the points and voltage drops (~9V if memory serves) that indicates a resistor. If the voltage with the points closed is still ~12.68v then there is no resistor. (I think this is the case... someone *please* correct me if this is wrong!)

Also, note that keeping a Pertronix I in the mode of "points closed" and 12V on the coil for an extended period of time is a no-no. Apparently it will eventually burn up the Pertronix. You can do this for short periods of time. I assume "short" is seconds up to a minute or so...

I too have a Pertronix I. I bought it that way with the resistor wire hooked up to it and a stock coil. It ran ok but (in my case) it runs much better with a full 12V *and* a coil made to handle 12V (like the Pertronix Flamethrower). Stock coils for the 1968 mustang are not designed to take 12V and *need* a resistor wire going to them. So if you do find that the resistor has been bypassed you should also ensure that the coil is designed to handle the higher voltage.

The world stands aside to let anyone pass who knows where he is going.
p51 is offline   Reply With Quote
Reply

  CaliforniaSpecial.com Forums > GT/CS and HCS Forums > GT/CS and HCS Discussions

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
1968 - 68 Hot Wheel GTCS on TV nineofive GT/CS and HCS Discussions 1 07/12/2014 06:48 AM
1968 - Rebuilt C4 is in but won't start or engage gear njmop GT/CS and HCS Discussions 33 02/22/2014 09:24 PM
1968 - Hot Start Problem Gregpet GT/CS and HCS Discussions 5 06/19/2009 03:42 PM
Where to start luisa2552 GT/CS and HCS Discussions 12 05/19/2005 12:24 PM
Rebuilt c4 start up PB gtcs GT/CS and HCS Discussions 1 08/27/2004 07:29 PM


All times are GMT -7. The time now is 08:19 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2017, vBulletin Solutions Inc.


This site created, owned and maintained by Jon Hanna - Copyright 1996-2011
All rights reserved. CaliforniaSpecial.com is not affiliated with Ford Motor Company

ShowCase vBulletin Plugins by Drive Thru Online, Inc.