Help Vacuum Leak Possibly carb Spacer

[Wolverine]

A buddy of mine is coming over next week w/ some misc tools , vacuum gauge , etc.

Good. Keep us posted on your vacuum gauge.

Here is a decent posting regarding what to look for:

http://expertscolumn.com/content/how-use-vacuum-gauge

I have a laser infra red temp gun I use for my pet reptiles, what is the temp I should look for in a normal and abnormal cylinder?

You are not necessarily looking for a specific temperature as much as you are looking for a large variance in temperature from one to the other. The hot ones are firing, the cold ones are either not firing.

Another way to accomplish this(much less exotic) is to start the car and remove one plug wire at a time. If the car runs worse, that cylinder is working hard. If there is no difference, than the cylinder is not working.

The best way to see this in practice is to try it on a good working car. Removing even 1 wire from a well running V8 can make a big difference.

Good luck.

Each cylinder had good spark when I grounded the wires

 

[Machman]

I found 7D26 cast in the front of the intake manifold any idea of the year? This mayl help me determine motor year

 

[c9zx]

I found 7D26 cast in the front of the intake manifold any idea of the year? This mayl help me determine motor year

April 26, 1977. Chuck

 

[Machman]

I found 7D26 cast in the front of the intake manifold any idea of the year? This mayl help me determine motor year

April 26, 1977. Chuck

Thank you VERY MUCH Chuck; I'm going to assume the manifold is a new replacement which may explain the Vacuum issue

 

[Jeff73Mach1]

solving a vacuum problem with a fuel pump that is not operating properly , is like giving mouth to mouth to someone that is bleeding from a slit throat.

 

[Machman]

solving a vacuum problem with a fuel pump that is not operating properly , is like giving mouth to mouth to someone that is bleeding from a slit throat.

Jeff do you think the fuel pump may be the main problem w/ vacuum being secondary? If so I will exchange the fuel pump in the car

I did a quick test w/ carb spray and noticed the rpms increased when I sprayed the area of the block off plate I had quickly made, so I will be getting a prof made one to seal that vacuum leak area.

 

[c9zx]

solving a vacuum problem with a fuel pump that is not operating properly , is like giving mouth to mouth to someone that is bleeding from a slit throat.

Jeff do you think the fuel pump may be the main problem w/ vacuum being secondary? If so I will exchange the 71 fuel pump in the car w/ a 77

I did a quick test w/ carb spray and noticed the rpms increased when I sprayed the area of the EGR block off plate I had quickly made when the EGR valve punctured, so I will be getting a prof made one to seal that vacuum leak area.

I don't know if this is of any help but, it is listed as being an EGR block off plate for 77 302, Mustang II. http://www.autozone.com/autozone/parts/Duralast-EGR-Valve-Block-Off-Plate/1977-Ford-Mustang/_/N-infu7Z9iyru?itemIdentifier=59390_0_11723_2425 Chuck

 

[Machman]

I think we possibly found the problem , My friend poped by this evening and brought a propane system for finding vacuum leaks , a vacuum gauge , and stethoscope for motors.

For the engine to keep running w/o konking we had to have the idle high so vac reading was appx 16 and when we lowered the idle and it managed to keep steady for a little while it was appx 20 ,

He hooked up the propane system and we tested all vacuum points and around the area of carb. We detected a leak between the carb body and spacer plate.

When the engine cooled I took off the carb and we found what may be the problem. The carb spacer has several areas on its surface w/ casting indentations in the design.

The carb base sealed around all areas of the spacer except where it met an indentation on the spacer rear and the gasket did not seal properly. this area is where we detected a vacuum leak during dynamic testing.

We figured that the carb was an early version (circa 1970 motocraft 2100)w/ a base that curved in on the base.

The manifold , and spacer are from 1977 and the proper carb for them would not curve in on the rear base but go straight accross from edge to edge. ( i saw a circa 1976 Motorcraft 2150 made for the later engines that did this.

He said I could have those indentations in the spacer filled them planed down if I still want to use the older carb or get a period correct carb from 76-77 and that should correct the problem.

He said it probably worked before I did anything as the entire area was filled with crud, coke , etc which sealed it for all those years.

I may do a quick test tomorrow and double up w/ 2 gaskets and see if it can be used as a temporary fix untill I can get the correct carb for it.

 

[Tnfastbk]

can you either sand it down or have it put on a lathe and turned enough to true/smooth it up?

 

[Machman]

can you either sand it down or have it put on a lathe and turned enough to true/smooth it up?

I don't have acces to a lathe and do not think I can flattten it good enough to make a sealing surface. Probably the best thing is to find a 302 carb from 76 or 77 with the correct profile on the bottom

 

[Tnfastbk]

can you either sand it down or have it put on a lathe and turned enough to true/smooth it up?

I don't have acces to a lathe and do not think I can flattten it good enough to make a sealing surface. Probably the best thing is to find a 302 carb from 76 or 77 with the correct profile on the bottom

A local machine shop will do it cheap

 

[Machman]

I took the carb out again and found something I never took apart, It was the booster venturi circuit. Almost every passage and jeting were clogged. I cleaned and unblocked the entire area.

Read the below article on motorcraft 2100 function.

http://carburetor-blog.com/?page_id=249

It mentions how this circuit works with vacuum making vacuum greater or less during running conditions Do you think this might be the culpret???

can you either sand it down or have it put on a lathe and turned enough to true/smooth it up?

I don't have acces to a lathe and do not think I can flattten it good enough to make a sealing surface. Probably the best thing is to find a 302 carb from 76 or 77 with the correct profile on the bottom

A local machine shop will do it cheap

Sadly no machine shop im my area would do it as it is too small for their machinery. I took a chance and did it myself and it seems to be good during propane test.

I found another problem that I fixed in the carb (see above). let me know if you think that may have been the problem as I have not tested the car yet.

 

[Jeff73Mach1]

Can't say if the fuel pump is the culpret unless you pressure test it.

To flatten something without machinery use a sheet of wet/dry sandpaper and a piece of glass. Wet the paper and stick it to the glass and use that like a big file without lifting the piece while moving it.

When you clean it off you will see any areas that are not flat.

The circuit you cleaned in the carb will help, but I doubt it is the problem-I'd suspect your baseplate. I have an old 2 barrel in the basement I can look at and send to you for parts if you want it. I have a 351C 2 barrel manifold too, but it is unlikely to be helpful lol

 

[Machman]

Can't say if the fuel pump is the culpret unless you pressure test it.

To flatten something without machinery use a sheet of wet/dry sandpaper and a piece of glass. Wet the paper and stick it to the glass and use that like a big file without lifting the piece while moving it.

When you clean it off you will see any areas that are not flat.

The circuit you cleaned in the carb will help, but I doubt it is the problem-I'd suspect your baseplate. I have an old 2 barrel in the basement I can look at and send to you for parts if you want it. I have a 351C 2 barrel manifold too, but it is unlikely to be helpful lol

Hi Jeff;

I wet sanded using emmery paper on a flat surface (glass) and got it pretty smooth. I'm not sure if the angle is slightly off ( it looked perfect but thats eyeballing which is not percise it so you never know)

The problem is almost gone and very minor as I was able to get the idle lower this time and I was also able to move the car up and down the driveway w/o stalling. Its still not perfect but better than it was.

Is the spacer you have the same type ?

 

[Jeff73Mach1]

No clue, I just pulled the intake and carb off of a craigslist engine I wanted for the block Be glad to look though.

I think it is your fuel pump. The fuel pump is driven by an eccentric mounted on the lower timing pulley. With the fuel pump unbolted, you can feel the eccentric thru the mount. If there are really multiple fuel pump for your year, I'd expect the main differences to be where the fuel line enters and exits and possibly the length of the arm that rides on the eccentric. Maybe it is pulsing fuel thru that filter as a result of a problem there and the carb issues were just an added bonus for your enjoyment.