Carburetor Adjusting Again

Since replacing the intake manifold, the engine has been running rather rich at up to 12:1 while just cruising around and even more rich when accelerating.  I decided I'd make a few jet adjustments today to evaluate the impact.

I checked the current jets and had 60's in the front bowl and 69's in the rear bowl.  The stock setup for a Holley 570 is 54's in the front with 65's in the rear.  This makes my configuration +6 in the front and +4 in the rear.  According to Holley, there is generally no need to increase jet sizes more than +4 over the original configuration.  

I decided to drop the fronts to 57's with 67's in the rear (+3 front/+2 rear).  After making the change, the a/f ratio was good at idle and around 14.5 or so when cruising.  Under light acceleration, it stayed roughly around 14:1 which leads me to believe the front jets are good.  However, when I accelerated hard, I noticed the engine go rich for a second and then quickly lean out and stay somewhat lean at 14:1.  

I decided to start with increasing the rear jet size again back to 69's.  After this change, the engine did not have as much of a lean spike on acceleration but was still rather lean at an average of 13.5:1.  I obviously need a bit more jetting to get the a/f ratio at the desirable 12.5:1 at full acceleration.

I did not really want to exceed the original rear jet size as I feel I would then be moving in the wrong direction.  I decided instead to increase the front jet size to 58's (+4).  After the change, under hard acceleration, the a/f ratio was near 13:1.  However, it seems that at cruise I have quite a bit of variation with the a/f at times going to 15:1.  

My current collection of jets include the following: 54, 56, 57, 58, 60, 62, 65, 67, & 69.  Seems like I would benefit from a set of 70's to run in the rear and leave the fronts alone.  

While I doubt there is much of a restriction, I wonder if I would be better off using a 670.  It is not suppose to impact my ability to have a reasonable a/f ratio.  I just wonder if jet sizes are so much large due to the flow of my engine with the new intake and heads.  If I were to switch to a Holley 670, the stock jet sizes are 65 and 69.  

I'm going to call it good enough for now.  As I drive more, I'll see what additional changes are necessary.

New Alpine CDE-172BT Stereo Install

Early in my restoration of the Mustang, I purchased an inexpensive Alpine radio on eBay.  The radio met my needs in that it had a CD player and worked as expected.  During the trip to Goodguy's last year, I noticed the CD player was not reading discs properly anymore.  I made a mental note and planned to get a new one at some point.

I purchased an Alpine CDE-172BT radio last week and installed it this morning.  The new radio is quite nice as it has bluetooth connectivity, CD player, AUX input, USB input, and high pass crossovers for the main speaker in case I elect to add a subwoofer.  The radio is no doubt more technologically advanced as it was made 16 years after the one it replaced.

In the image below, the old radio (CDM-7874) is pictured above the new (CDE-172BT).

I purchased another Alpine as I sold and installed them many years ago and was always impressed with their quality.  Additionally, I prefer a radio with a volume knob and Alpine continues to use them almost exclusively in their radios.

I spent about three hours installing the radio which is rather excessive.  I soldered all of my connections, used heat shrink, and then spent some time organizing the wiring under the dash with some zip ties.  Finally, I added a thick bracket to the back of the radio and attached it to the bottom of the dash to hold everything secure.

I do expect to add an amplifier and subwoofer later.  I actually have both available from a previous vehicle I owned.  I'd just need to take the time to make a custom enclosure for the Mustang.  I'd like to work on this in the near future to finish up the stereo install.

Replacement of Steering Column Seal

I've replaced the column seal between the steering column and firewall on three separate occasions now.  Each time, the new seal seems perfectly fine when installed but begins to rip or generally deteriorate in a year or two.  This then allows air in from the engine compartment.

This time, I decided to buy a steering column seal for a 1969 Mustang to see if it would work in a 1967 Mustang.  While I was originally concerned, the bolt pattern matches perfectly.  The steering column angle is the same.  The collar which slides down the column fits quite well.  The revised design does not seem to put stress on the rubber so I'm hopeful it will match much longer.

There is no much to see with this particular part so I don't have pictures to share.  I did have to remove the steering column again to get it installed.  While out, I touched up some of the paint on the steering column to keep things looking nice. 

Small Projects for the Weekend

The next projects I'd like to work on focus on improving driving comfort....

1) Seal interior better
2) Reduce exhaust noise
3) Improve stereo system
4) Add air conditioning

I decided to start with sealing up the interior a little better. 

There is a hole in the firewall where I ran in the O2 sensor wire.  I expected to only run it temporarily so I did not do much to fill the hole.  Now several years later, I picked up a rubber grommet from Lowe's and used it to seal up the area so the O2 sensor still works but no fuel or exhaust smell comes into the cabin.

I then decided to start work on fixing the seal around the steering column.  The stock seal is horrible.  I've replaced it three times and it continues to rip.  I'm thinking through a way I could build something different that uses a different style of weatherstripping which will hopefully hold up better.

While checking around the truck, I found the reverse light wiring seals were not put into the trunk drop down panels well.  I managed to get these back in place which could keep some more exhaust smell out.

There was also a small seal where the license plate wiring went through the taillight panel.  I found a way to use a small gasket to mostly seal of this area which should help further with exhaust fumes.

I'm taking these steps not because the exhaust or fuel smell is bad now.  However, my wife does not like to ride in it because she says it smells.  Additionally, if I get an A/C, I will be able to smell it more than I do now as I'll be driving with the windows up more.

New Intake Manifold - Test and Tune

Tonight, I added coolant to the radiator and then started up the Mustang.  The Mustang started fairly easily and I quickly checked the timing to find it was at 15 degrees BTDC which is fine.  I let the engine warm up and started checking for leaks.  Once I found the first leak, I turned it off.

I noticed the fuel line to the carburetor was leaking at the carburetor.  I fixed that and found that the power wire to the electric choke was broken off at the connector so I fixed it.  With these fixed, I started it back up again allowing it to come to operating temperature.

The A/F ratio was incredibly high at idle (11:1).  I checked and the idle screws were 3.5 turns out which is unheard of but was needed with the previous intake leak.  I found that I could get it to 13.5:1 when .75 turns out.  I could do a little more to set better but I left it at that for now to drive it around the block.

I drove it and the A/F ratio is good but a little rich under heavy throttle.  I'm surprised at how smooth the engine runs now compared to before.  It is much smoother at idle and while cruising around which is nice.  There is more power.  When I get on it, I don't smell oil burning either which is nice.

I parked it and found coolant leaking from the thermostat housing.  I found the bolts were not very tight so I tightened them and cleaned up the spilled coolant before it could damage the newly painted parts.  I hope this does not leak any more as it has since I purchased the car and I think the problem is the old thermostat housing.

After the car cooled down, I torqued all the intake bolts back to 20 ft/lbs.  I'm calling this project done.  I've very glad I decided to do it.  I mostly wanted to do it for the looks but I was also curious if there was a leak.  Fixing the leak I found has fixed many small problems and was well worth the time.

New Intake Manifold - Ready for Fluids

This evenings project was to reinstall all the various items I removed so I can add fluids and then start up the Mustang.  I installed everything except the coolant just to provide one more night of drying time for the RTV.

I installed the distributor, heater hoses, radiator hoses, carburetor, throttle linkage, fuel lines, and then replaced all the spark plugs (NGK FR5 7373).  The old plugs looked worse than they did when I checked back in November.  Several were so fouled I just threw them in the trash.  I held on to the best four to place in my spare parts bin in the truck on the car.

Tomorrow night, I will all coolant, start up the Mustang, check timing, and then start the process of tuning over again in hopes of reaching a good air-fuel ratio.

New Intake Manifold - Intake Installed

This evening after work I installed the new intake manifold.  I started by cleaning all the mating surfaces several times with paint thinner to ensure everything was completely clean.  I then installed four 4" bolts with the heads cut off to help in aligning the intake for install.

I used Permatex Gasket Sealant around a few bolt holes on the head itself and then on the mating surface of the intake gasket.  While it started drying, I put some Permatex Ultra Grey Gasket RTV around the water ports below and on top of the intake gasket. I then installed the gaskets and test fit the intake to see the amount of RTV which would be needed at the edges.

The intake came back off at that point and I put a bead of the Ultra Grey in the corners of the intake followed by a bead across the front and back.  I then put the intake on one last time and installed all the bolts finger tight.  I let the intake set for 45 minutes like this and then torqued all the intake bolts down in the proper sequence to 20 ft-lbs.

I waited to install the intake as I decided last minute to switch to a Fel-Pro 1250S-3 intake gasket because it has a steal core.  Sounds like overkill but I don't want this thing cracking and coming apart like the last one did.  I'll just sell the 1250 gasket I purchased along with the old intake manifold.

New Intake Manifold - Painting and Clean-Up

Today I spent a little time cleaning up and preparing to install the intake manifold.  I'd go ahead and install it but I decided to use a Fel-Pro 1250S gaseket which is metal lined instead.  It will take a few days to get here but it is added insurance so that I don't have the same problem with the gasket as last time.

I painted the timing cover and water pump were the leaky thermostat housing discolored it over the past couple of years.  This took some time as I had to remove quite a bit and then use some strips of tape to cover bolts and pieces of plastic to protect everything from overspray.  The job took a bit but the engine looks good again.  

New Intake Manifold - Installation Discovery

I'm working a small amount on the intake installation in the evenings.  I work for a bit and then take a break for the evening as it is rather hot in the garage and I'm in no hurry to get the job done.  

While working on the car last night, I took a picture if the engine before removing the intake.  I've become familiar with seeing the blue intake on top from when I painted it years ago.  I expect it will look quite a bit better with the bare aluminum intake.  

Once I removed the intake, I found the gasket was in horrible condition.  There are two cylinders (#6 and #2) where the intake gasket cracked and caused very clear leaks to the top side of the motor.  There are several cylinders (#3, 5, 6, and 7) with leaks to the interior of the engine.  The intake slid over so that it actually blocked the ports on cylinder 6 and 7 to a degree. 

I'm quite shocked at the condition of the intake manifold.  The front two bolts felt a little lose when removing them but the rest did not seem too loose.  The center bolts were tight but they did not feel over torqued.  I'm not sure what caused this to occur and how long it has been this bad.

I'm a bit concerned about the situation as I purchased the same FelPro 1250 gasket for the new intake.  I remember installing the intake last time and I was incredibly meticulous about every task of installing the components as I wanted it perfect.  The following picture is from the install and shows the gasket adhesive, rtv around the intake ports, and everything looks perfect.  I can only assume bolts came loose over time or were not torqued properly and slowly the gasket deformed.

This explains the difficulty I have experienced when trying to tune the carburetor.  I would reject the carburetor and it would seem better but then be lean again over time.  This is concerning as I was likely making certain cylinders incredibly rich so the O2 reading averaged out properly while certain cylinders were very lean.

The second item this explains is the burning of oil.  I thought the engine was picking it up through the PCV valve.  I did not expect a leak between the lifter valley and intake to be the cause.  It is most certainly the main cause of the problem.

Lastly, I noticed before when performing a compression check that cylinder 3 and 7 had strange looking spark plugs.  I think those two were lean from breaks in the intake manifold.  Looking back at the pictures, cylinder 5 was also darker than the rest and that is likely from oil entering that cylinder because the gasket is all deformed. 

I'll be happy to get this job done and see how the engine runs.  I'm curious if I will notice any improvement in the performance.

New Intake Manifold - Edlebrock RPM Air Gap

There are numerous items which still need work on the Mustang.  One would think I would continue to work on untouched areas to finish up the restoration.  Instead, I replace gears I installed a short time ago and am now going to replace a perfectly good intake.

The existing intake is a Weiand Stealth (#8020WND) which I installed in 2009 with my Holley Street Avenger carburetor.  While there are no issues with the intake, I'd like to switch over to an Edelbrock RPM Air Gap intake.  I don't expect much if any improvement in performance but want to switch for appearance reasons and to have the carburetor run a little cooler.

On Sunday evening, I purchased an Edelbrock RPM Air Gap intake (#7521), Scott Drake aluminum thermostat housing (#SDK-C5OE-8592-A), a set of FelPro intake gaskets (#1250), and a FelPro 35067 thermostat gasket.  In normal fashion, Summit sent them to me in record time.

I drove the car this evening to take a picture with my son and the 2006 Mustang he just purchased.  I've been wanting to take the picture with him since we purchased it about three weeks ago and just now found the opportunity.  Now I can pull the intake and swap it without worrying about taking the car out of commission for a few days or longer if I choose.

Rear Gear Ratio Upgrade - Part Two

The shop installed the new set of Motive 3.80 gears in my differential in just a few hours.  The gear pattern paint looks good from my limited experience of having one other gear set done.

My schedule has been very busy lately so the assembled carrier on the garage floor for a few weeks before I installed it this weekend.  I cleaned it some and put a few light coats of the original paint back on the carrier to cover some scratches left from the machine shop.

The carrier is very heavy and it took a few times of lifting it before I was able to get it up and into place with the exhaust still installed.  I used a new Fel-Pro gasket with a light layer of RTV.  Additionally, I used a new set of copper washers and locking nuts.  I was not as meticulous as in the past with cleaning up everything after the install (brakes, driveshaft, etc) but the job is done.

I sold the old set of 3.25 gears on eBay which paid for the installation of the new gears.  No reason the have the 3.25 laying around as I do not expect to switch back.