302 to 460 Engine Swap
The little 302 that has served so well is just not up to the task now that I have 1-ton axles and larger tires. My wife and I also purchased a holiday trailer recently [25 ft Komfort] and pulling that is definitely too much for the small-block.
Fortunately, when I parted out the 1986 F350 for its drive-train and other things last year, I also kept the engine. It is a [formerly] propane-powered 460 [7.5 litre] that is in great condition. When I drove the F350 home last year, it ran beautifully and had lots of power. I will be swapping out the 302 for the 460 and converting it back to gasoline power.
Here is a picture of the 460 just after I pulled it from the F350 last year:
It was a little dirty on the outside, but the inside proved to be spotless. I cleaned it up a little, replaced a few gaskets and seals; added a fuel pump for the gasoline, and replaced the factory engine mounts with a pair from Jeff's Bronco Graveyard. I also installed an Edelbrock Performer 460 intake that I found on ebay. This should help the engine to breath a little easier. I also have a Holley 780 cfm carb that I recently rebuilt to complete the conversion back to gasoline.
The engine has not been painted...but it's what's inside that counts:
During the course of this swap, I will also be upgrading my brakes with a heavy-duty power brake booster and an F350 master cylinder. I will also be converting the clutch mechanism from push-rod to hydraulic. The bell-housing for the 460 requires a hydraulic clutch mechanism...so the old push-rod clutch has to go away.
Day 1: March 25th, 2005
Today I began the swap. I wanted to get all the old parts out today. Hood, radiator, and grill removal first. Then I chopped out the exhaust system [it's garbage anyway]. I first tried to pull the engine while leaving in the transmission and transfer case. That didn't work at all and I ended up pulling everything out.
Now I have a very large hole that will allow me to do some cleanup and give me easy access for the brake a clutch work:
Day 2: March 26th, 2005
Today my goal was to complete the brake and clutch changes. I was successful in getting the brakes modified with the heavy-duty power booster and F350 master cylinder. As far as the clutch changes go....some success, and I should get it all done tomorrow.
The first picture is the firewall with the existing brake booster and master cylinder removed. The second shot....not so great...is showing the pilot hole that I drilled for the clutch master cylinder. It is in about the centre of the frame and is 2 1/8" above the factory screw and is 1 1/4" to the left of another factory screw. This pilot hole will be enlarged to 3/8" to accommodate the lower mounting bolt of the clutch master cylinder. I spent some time at the wrecking yard to get my measurements.
Above the first hole you can see the second hole that I drilled. It is 2 7/8" above the lower hole, and it will also be enlarged to 3/8". I will also be cutting a 1.5" hole between these pilot holes to accommodate the pushrod for the clutch master cylinder. I will be completing this tomorrow.
The first picture below is a comparison of the arms that are attached to the end of the clutch pedal and activate the clutch mechanism. The arm on the left came out of my Bronco and is used with the pushrod clutch. You can see that it is quite worn and would have failed soon. The arm on the right is used with a hydraulic clutch. I have placed them in their relative positions as they are when the clutch pedal is released.
I was hoping that the arm that came out of my Bronco would have the same attaching method as the one I got from the wrecker....as you can see, they are quite different.
My solution was to chop the tops off both of them and weld the older top on the newer arm. I put the old arm back in its original position on the clutch pedal and held the new one up against it so that I could draw a line for cutting. Preliminary measurements indicate that I have got it right, but I will not weld it up permanent until I have the clutch master cylinder installed and I know for sure.
The following are pictures of the new [well....new from the wrecker] power booster, the master cylinder installed and being bled; and finally, the master cylinder is all done with the hydraulic lines reconnected. I still need to bleed the brakes at the wheels in order to ensure that all the air has been purged from the system.
Day 3: March 27th, 2005
Today was a fairly productive day; I completed the installation of the hydraulic clutch and got the 460 nestled into the engine bay. Tomorrow will be spent re-installing drive-train and buttoning things up.
The first picture was taken after I had finished drilling the holes for the clutch master cylinder. What you cannot see is the grinding that had to be done inside the cab on the steering column flange to accommodate the nut for the lower bolt on the master cylinder. The second picture shows the clutch mechanism all installed. The third picture [yep...those are my shoes too] is the slight modification that I needed to make to the clutch actuator arm to make it fit properly. The last picture immediately below is the finished arm, all welded, cleaned up, and painted.
These two pictures show the 460 on the stand with a few of its ancillary items re-installed. The last picture shows it resting nicely in the engine bay. I dropped this in myself, so there was a little swearing a shoving to get the engine mounts lined up properly. The oil filter adapter is right up against the frame, but I am counting on the engine rotating back a little when the transmission is installed and bolted in place....that begins tomorrow.
Day 4: March 28th, 2005
No pictures today....the progress today was slow and the stuff I did was not worth a picture anyway:
The passenger side exhaust header is going to be a little difficult. There is a factory cut in the flange on the rear-most pipe. It looks like this piece was installed separately to get around the starter. It is a little rusted now, so I will be cutting the pipe to allow the installation and re-welding it once I have it installed.
One last thing....I will need to set up a remote oil filter, the factory adapter for the oil filter does hit the cross-member, but it looks like there is enough room for a remote adapter.
Hopefully tomorrow I will be able to fire up the engine.
Day 5: March 29th, 2005
Today was not as productive as I would have liked. I did get the Holley carb and passenger side exhaust header installed....that was a battle. I think that it had more to do with my own inexperience as much as anything else. I cut off the last pipe to ease the install, then I welded on a new sleeve to allow me to put it back together. Working in the narrow confines and around the starter motor was a bit of a challenge, but I got it done. The fourth photo shows the patch that I had to weld on after blowing through the pipe due to the welder being set too high. It looks terrible, but it should be all sealed up.
The oil filter is another area that needed some attention. The factory oil filter adapter hits the cross-member, so I removed it to add a remote filter setup. The first picture is a nut [that was in the engine block] that held on the adapter. I needed to grind off the material above the hex nut so that the remote adapter would fit properly. The second shot shows the oil filter location on the block with the nut removed. The third photo is the modified nut with a 1/2" NPT nipple added. Picture four shows it added to the block, and the final photo shows the remote adapter installed and ready for oil lines.
Things left to do to get it ready to fire up:
Hopefully I will get a few of these items knocked off tomorrow.
Day 6: April 1st, 2005
I now have the transfer case and drive shafts re-installed. I have also hooked up the clutch. Tomorrow [Saturday], I will see how much I can get done, hopefully it will be running tomorrow.
Day 7: April 2nd, 2005
Still not running.....but it is close.
I now have the shifters re-connected and the skid plate back on to protect the transfer case. The power steering pump is installed and the ignition system is hooked up. I have also bled the clutch and aside from needing to get a bushing for the pushrod, it is done and working fine. I still need to connect fuel and oil lines, I also need to connect the power steering return lines to the cooler once I have the grill re-installed. The final step will be to connect the throttle linkage....I need to make a slight modification to the carb throttle arm to accommodate the linkage.
Day 8: April 9th, 2005
I needed to take a few days off the project....however, today was a great day....the Bronco lives again!
My first order of business was to cut a small notch out of the engine cross-member so that I could hook up the oil lines. This job was a pain in the behind....had I known that I would be notching the cross-member I would have done it with the engine removed. It seemed to work out OK though. I was able to connect the oil lines and attach the oil filter to the fender. Oil changes will be a bit messy, but at least the filter will be easy to reach.
Once the oil lines were taken care of, I tackled the cooling system. When I parted out the F350, I kept the grill and radiator. The rad for the 460 is much larger [both in width and number of cores] than the 302 rad. The mounting method is also different. I was going to simply install the F350 grill into my Bronco, but it was very rusty; so I decided to modify my Bronco grill instead.
Pictures 1 and 2 below show where I cut out some sheet-metal to increase the airflow for the larger radiator. Picture 3 shows the radiator support that I removed from the F350 grill and welded onto the Bronco grill. Except for the radiator mounts, the 1986 F350 grill is exactly the same as my 1981 Bronco grill. Picture 4 shows the 460 rad being test-fit in the Bronco grill.....perfect fit. I just needed to drill some holes to accommodate the bolts at the top, and I was done.
The picture below shows the modified Bronco grill back in place. I connected up the cooling system hoses, the fuel lines, and the power steering plumbing.
The power steering was a little complicated due to the fact that I will be installing the Milemarker hydraulic winch, the power steering lines go as follows...PS Pump to winch, winch to steering box, steering box to trans cooler, trans cooler to hydraulic filter, filter to PS pump return. I will probably get the winch installed later this week.
I filled all the applicable fluids and connected the engine electrical [the F350 engine electrical is identical to my Bronco], re-checked all my work, then I cranked it over for 45 seconds [no ignition] to pre-oil everything. Then I fired it up....barely ran......crap!
I discovered that the timing was off, that was a quick fix. I also had a fuel leak, also an easy fix. I fired it up again and this time it ran very nicely [very loud with the open headers mind you]. While it was running I topped up the coolant and PS fluid and I checked for leaks. I soon discovered a very large oil leak coming from one of my remote oil lines at the engine block. I shut the engine down and decided that this was enough for one day.
Tomorrow I will fix the oil leak, and fire it up again and let it warm up to see if there are any more leaks. I will then verify the ignition timing and do a little carb tuning to finish things off before I deal with the winch and exhaust system.
Day 9: April 10th, 2005
Today was a very productive day. I found the oil leak:
As you can see, it looks like I tightened up the fitting a little too much. A new oil filter adapter will be required. I also ground off a little more from the cross-member so that I can have an easier time re-fitting the oil lines.
I also mounted the hydraulic winch. It was not too difficult, I was very careful that my holes were precisely drilled in the 10x4.5 inch pattern required and it bolted right on [using 3/8" grade 8 bolts]. I also mounted the cable fairlead by simply welding it onto the bumper. I can grind off the welds if I need to remove it.
I still need to connect the hydraulics for the winch, re-connect the oil lines, and connect the throttle linkage. I will be good to go except for the exhaust system.
Day 10: April 16th, 2005
The other day I decided to cut out a little more of the cross-member so that I could do away with the remote oil filter all together. It turned out to be OK, however, I may beef up the cross-member just a bit.
The first picture is the oil filter looking from above....not a great photo. The next picture is from below, showing how I notched out the cross-member. There is more room between the filter and the cross-member than the picture shows, no fear of the engine torquing the filter into the cross-member.
I also completed the hydraulic winch installation. It went very well and works nicely. The first picture is the remote filter for the PS fluid. The second picture shows the fittings for the PS pump and the steering box. Picture three is the fittings at the winch, and the fourth picture is a shot of the winch with the cable installed. The final picture shows where I installed the plug for the winch control, right beside the driver's side headlight.
I still need to do the following:
This has been a very interesting project; my next update will be after I take care of the final odds and ends and take it out for a test drive.
Update: April 20th, 2005
The hood is now installed and aligned. I have also bled the air out of the brakes and the hydraulic clutch. The coolant leak is fixed, it was actually leaking past the threads of one of the thermostat cover bolts....so a little thread seal is all that was needed there.
I need to drop the fuel tank; I will do that tomorrow. The fuel sender needs to be replaced, and to do that I have to drop the tank. The new mechanical fuel pump has an overflow that I need to run back to the tank as well, so I will be modifying the new fuel gauge sender by adding a fitting to accommodate the return line. Once that is all done, I can work on the carb tuning again.
I also bought a muffler and some pipe and fittings so that I can build an exhaust system. I hope to have all this completed before the end of the weekend. Pictures will be posted when done.
Update: April 22nd, 2005
I dropped the tank today and discovered a couple of things; firstly, I needed to replace the tank. There were a couple of rust spots that immediately began to leak when I disturbed them. The following picture is the worst of them:
On the positive side, my Bronco was already outfitted with the larger 33 gallon [about 125 litre] tank, so no modifications to the factory skidpan were required to add the new tank [I was buying the bigger one no matter what!].
I also discovered that my fuel sender was working properly, it was the float that was defective. It developed a leak and filled up with fuel....so the fuel gauge always read empty because the float ...didn't. The following pictures are the pinhole in the float [it is the tiny dent] and my soldering job to patch it.
I also modified the sender to add an extra line for the fuel return line from the fuel pump. I soldered in some copper tube and added an extension so that I would not have to listen to fuel dribbling back into the tank.
I removed the carb and did a proper job of setting the float height, and added a small pressure gauge to the fuel line. I am now getting the proper [5 psi] fuel pressure. I started the engine, no fuel leaks, and the fuel gauge actually works....now I just need to build that exhaust system.
Update: May 17th, 2005
The exhaust system is finished and working well. I built a dual exhaust system, pictures below:
I had to bring both pipes over to the passenger side, then over the cross-member before running to the mufflers. I kept both sides equal distance by running the driver's side exhaust through the passenger side muffler and vice versa.
I also had to change the intake gasket, it was leaking a little coolant. Luckily, none of it got into the engine. My fuel economy is the same as it was with the 302....13 mpg. Not great economy, but I am happy with it. I have tons of power now! Plenty of bottom end torque and much greater top end range. I can rev this 460 much higher than I could ever run the 302. It is really nice to come to a hill on the highway and just add more pedal rather than slowing down and shifting down.
I have since re-jetted the carb for my altitude [4,000 ft above sea level] by dropping two sizes from stock in both the primary and secondary venturis. It now runs better and I should get even better fuel mileage than with the first mileage check. I also checked and reset the fuel float level [in the carb] and the idle mixture also seems about right.