1975 Suburban - Engine Rebuild
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The series of photos below are the "straight off the camera" shots I've been taking during the engine rebuild. The motor doesn't look terminal, but it sure does need a rebuild. My favorite photos so far are of the engine way up in the air getting it out of the truck (Holy heavy hanging metal, Batman!) and the 2 photos comparing the slack in the timing chain. :-) My favorite "Hmmm, that's not supposed to happen" moment was when I got the engine on the stand and removed the drain plug to drain the oil. The plug is the kind with a small magnet in the end of it to collect debris - and boy did it. I had a pile of gray metallic sludge about as big as the end of my thumb clumped onto it when I pulled it out of the oil pan. ("It's never done that before...") I also found out that there's a good gallon and a half of antifreeze still in the block once you get it on the stand - even after the water pump is removed. I'm lucky I had some spare (unused) kitty litter (er, I mean absorbent material) around...

 

Engine Extraction

SuburbanEngineRemoval 001.jpg (356692 bytes) Where'd all those wires go, anyway? Check out my remote solenoid conversion and wiring for the driving lights. Yay. Even with this photo I managed to hook things up wrong after the engine rebuild and have the switch operating inverted from normal.

SuburbanEngineRemoval 002.jpg (329929 bytes) "Just a little higher..."

SuburbanEngineRemoval 003.jpg (396570 bytes) That orange thing is the torque converter. I sure hope it doesn't fall out before I get the engine back in - it's still full of transmission fluid! Check out the old scissors jack and wood blocks holding the front of the transmission up.

SuburbanEngineRemoval 004.jpg (309359 bytes) Up, up, and away!

SuburbanEngineRemoval 005.jpg (305706 bytes) Yes kids, the motor really is about six feet off the ground here!

 

Engine Teardown

SuburbanEngineRemoval 006.jpg (322602 bytes) Which way does the flywheel mount to the crank?

SuburbanEngineRemoval 007.jpg (369422 bytes) With the extra hole in the crank lined up with the one in the flywheel.

SuburbanEngineRemoval 008.jpg (327906 bytes) The fun begins. Note large spread of kitty litter. Oops.

SuburbanEngineRemoval 009.jpg (323834 bytes) The heads and intake were nice and clean not so long ago. Not too bad, but not as nice as it was before...

SuburbanEngineRemoval 010.jpg (381383 bytes) So far, so good. The intake sure was a pain to get off. I've seen superglue let go easier that these gaskets and sealer did. At least I managed not to mangle anything. I hope.

SuburbanEngineTeardown 001.jpg (313429 bytes) Pretty... Pretty greasy, that is. This thing drooled on itself like a hungry baby. Yuck.

SuburbanEngineTeardown 002.jpg (348826 bytes) Look at the amount of sludge on the pistons. Blow-by or bad valve seals. :-( Also, look carefully at the second piston from the left. Looks like I had something bouncing around in the cylinder recently. Hmm...

SuburbanEngineTeardown 003.jpg (348685 bytes) More piston sludge.

SuburbanEngineTeardown 004.jpg (437752 bytes) At least the intake valley is reasonably clean...

SuburbanEngineTeardown 005.jpg (347983 bytes) Look ma - a wasted timing chain!

SuburbanEngineTeardown 006.jpg (338043 bytes) Compare the slack from the previous photo. Yikes! No wonder I could never set the timing right...

SuburbanEngineTeardown 007.jpg (358486 bytes) One very greasy bottom end... It's major redeeming value is that it's a "4-bolt" bottom end. Cool. :-)

SuburbanEngineTeardown 008.jpg (440064 bytes) Same thing from the other side.

SuburbanEngineTeardown 009.jpg (364129 bytes) These heads were "new" about 20,000 miles ago. Look at the top intake valve - there's oil dripping out around it! I think I got ripped off by the place I bought the rebuilt heads from...

SuburbanEngineTeardown 011.jpg (416252 bytes) The bare block, ready for a quick degreasing and a trip to the the machine shop

SuburbanEngineTeardown 010.jpg (284014 bytes) The main bearing caps and bearings. Check out the pounding the bearings took. I'll give you a hint - the copper is something like the second or third layer of metal inside the bearing!

SuburbanEngineTeardown 014.jpg (224346 bytes) A close-up of the #1 main bearing. Weird that it wore on the upper bearing harder than the lower one, but that's what happened.

SuburbanEngineTeardown 012.jpg (307765 bytes) The pistons and rods with the bearings still in them. Same deal - check out the copper! I was only a few hundred miles from a thrown rod or spun bearing...

SuburbanEngineTeardown 013.jpg (259892 bytes) A close-up of the rod bearings... Check out the score markings in the nearer bearing. The upper part of the rod bearings took the bounding here.

SuburbanEngineTeardown 015.jpg (362109 bytes) The crank came out looking OK. No score marks and nothing deep enough to catch a thumb-nail on. It'll probably have to go .010/.010 under to clean up, but that's pretty typical of a 180,000 mile motor.

 

The Spending Spree

I sent the motor out to the machine shop, and got mixed news. The block was good, but it was already a bit beyond .040" over, so it would have to go .060" over to clean up. One head was cracked (so much for the nice new rebuilt heads I got from B&B a few years ago), the crank was wasted (too worn to salvage), and the balancer was thrashed - but the rods were fine. I ended up spending $1200 on the parts, machine work, and balancing. More than I wanted, but not as bad as it could have been. So, I got everything home, cleaned up and painted stuff, and started working on the re-assembly process. The red in the lifter valley is just the color of Rustoleuom I grabbed to paint that area to promote better oil drain back.

I got some nifty tools for this work, some of which can be seen in the photos. One is a socket that goes over the front of the crankshaft and allows you to turn it using the key instead of the front bolt on the crank (which could snap off) and the other is a plastic rod guide to allow easy one-man piston installation without risk of scratching the cylinder walls or crank journals. I also bought a degree wheel kit from PAW, but the dial indicator holder it came with is kinda cheesy. If I can't find a decent base/dial indicator holder, I may return it and get a different brand with a better setup.

 

Engine Re-Assembly and Installation

I've gotten the bottom end back together, and I finally installed the oil pump, cam, lifters, timing chain, and front cover. I've gotten started painted the heads so I can install them, and I'll be installing the balancer as soon as I can get it to slip over the front of the crank snout - I'm leaving it in the house overnight to warm it up (and hopefully) expand it enough to slide over without too much extra work to "convince" it to go on.

The balancer bolt turned out to be a nightmare to get in. First the threads stripped out on the bolt, then the balancer installer tool pulled the threads out of the front of the crank. So I helicoiled it. Then the front half of the helicoil threads pulled out when I was doing the final tightening of the balancer bolt. I put in a new helicoil with thread locker and let it set overnight. Then I used the longest possible bolt I could fit into the bolt hole to grab the maximum number of threads - and it worked. Still, either the remanufactured crank or the remanufactured balancer the machine shop sold me with the rebuild kit was a piece of crap. To their credit, they did offer to "get the balancer bolted on properly" if I brought the partially assembled engine to them. I wasn't too thrilled at the prospect of dragging my half-assembled motor down to the machine shop in the back of an open pickup in Seattle where it rains way too much, but at least they were semi-helpful about it.

While I was puzzling over the balancer bolt issue and not assembling much on the motor, I took some time to pressure wash and spray bomb the frame rails in the engine compartment. I literally got a bucket full of pure sludge off the frame - it was pretty nasty in there due to the oil leak that lead to the demise of my bearings. I suspect the spray paint won't adhere all too well, but at least it will keep it from getting too nasty before the inevitable oil leaks give the frame a new protective coating... :-)

After I got the balancer bolted on, I wrapped up the engine assembly process. The water pump, pulleys, alternator, accessory brackets, and the intake manifold were all cleaned (and repainted if needed) and re-installed.

I found out that to properly pre-lube the engine, you need a pre-lube tool that seals off the oil passage between the left and right side of the block, otherwise only the left (driver's side) of the block gets any oil pressure. The easiest way to do this is to buy a rebuilt points distributor and modify it to be able to chuck it into your drill and to spin the oil pump without spinning the camshaft. You do this by removing the advance mechanisms (vacuum and mechanical) along with the points and their mounting plate. Then you grind off the top plate where the advance weights mount so you can chuck the shaft in your drill. Then you grind the teeth off the gear so that it will engage the oil pump shaft without engaging the distributor drive gear on the camshaft. (Note that the inner shaft and what's left of the gear assembly can fall out of the bottom of the distributor housing once you do this, so don't drop it into the engine!) Insert the assembly into the engine like it was a distributor and chuck the shaft into your favorite 1/2" electric drill. With this tool you pre-lube the engine like you would with any other similar tool. You operate the drill in the same direction that the distributor normally rotates and it spins the oil pump (without the engine internals spinning) to provide oil pressure to the entire engine. (On the Chevy 350 this is clockwise if my memory is correct.) Hook up a mechanical oil pressure gauge to see if you're getting the right amount of oil pressure, make sure you have oil in the engine, an oil filter installed, and then go gung-ho with the drill run for a few minutes. When you see oil dripping from all 16 rocker arms, you're done. (Beware, with no valve covers on the engine, it will tend to drip all over the place and make a real mess... That drip pan I bought from Jegs for my engine came in quite handy for this process...) Also, you can see the top of the pre-lube tool I created in the back of a few of the photos. I'm going to have to put up a special page on this - you can easily build this handy little tool for almost any engine that drives the oil pump off the distributor for under $40 - and the benefits to doing this pre-lube while the engine is on the stand (to check for leaks and correct oil pressure) and then right before you fire up the motor (so it's not a "dry start") are very large. It's money and time well spent.

After I verified that I had oil where I was supposed to and there were no leaks, I installed the valve covers. If you look closely, you can see that the last set of photos (#25 and #26) have the valve covers reversed from the first few photos. That's because I put them on the wrong sides of the engine - I got them correct front to back, but I put the oil fill opening right under where the AC compressor goes. (Oops.) I didn't figure this out until I was trying to re-install the PCV valve and hose that I had on the engine before the rebuild. Since the hose had kept it's shape, and obviously would not fit with things in the wrong place, I was able to figure this out and fix it before I installed the engine. Even better, the gaskets had not "set" yet, so I was able to re-use them. Hopefully they won't leak. (This is one more reason why you should always save your old parts until you get the new ones installed correctly.) Unfortunately, I managed to mangle the old PCV valve grommet I had in the process, so I need to replace it. I probably needed a new one anyway, so it's not a big deal.

I finally got around to installing the engine into the truck again, thanks to some help from my friend Jack Mayo. (I had to swap labor with him to help get his engine into his Camaro, but I had fun doing that.. Also, Jack had tons of fun playing with my parts washer and media blaster. He now has tool-envy. :-) My engine stand is much lighter now, and decidedly lonely. (Time to find another engine to work on - like a 401 for my '58 Buick... :-) I also had some help from another friend to re-install the hood. You can see in the engine removal photos that the hood is off, but what isn't pictured is the very "Sanford and Son" blue tarp that covered the front of the truck while all this work was going on. (Getting the engine compartment rained on directly promotes rust, gets in all the wiring and messes it up, and tends to result in the hood hinges rusting solid in the open position. Not cool.) I'm sure my neighbors are much happier now that it looks like a vehicle again and not a junkyard. (It does need a serious bath though.) I also found out that I can't hook the drill up to the pre-lube tool once the engine was in the truck - the firewall is in the way. Ugh. I had to go up to the Harbor Freight store and buy a right angle adaptor for the drill... Also, I managed to lose the three bolts that hold the torque converter to the flexplate, so I need to go buy some new ones. I was thinking about doing it anyway (they hold all of the power being transmitted from the engine to the trans - just a wee bit important...) but I hadn't bought any new ones when I bought the rest of the "new" ARP bolts I got from Jegs. Since I needed to pay for 2nd day shipping to the bolts here before the weekend, I bought some other small stuff from Jegs that I'd been meaning to get anyway.

Next up was getting a bunch of the small stuff done. The radiator hoses and heater hoses, the fan and shroud, most of the wiring, the new battery cables, the carb and throttle linkage, the line for the factory oil pressure gauge to the fitting on the engine, the hoses to and from the fuel pump, and all of the vacuum lines all got hooked up. I also took advantage of a spare set of hands (thanks, Jon!) that were over at my place to help get the headers installed onto the engine and hooked up the exhaust system. I even finally managed to get what I hope are the correct bolts to hook up the torque converter to the flexplate. I also mounted the power steering pump to the engine and tightened up the adjustment on the alternator belt. I installed the plugs, and in the process of buying new ones I found out that my local parts store can't seem to find any that are short (so they fit behind the headers) and are gapped something reasonably close to the .060" factory spec. I have all of the existing plug wires and the Accel coil transferred to my new clear distributor cap, and the wires and brackets are installed on the engine with the cap ready to mount onto the distributor as soon as I install it. With the help of my every-faithful wife, I got the motor to what I hope is TDC for cylinder #1 and I installed the inspection cover on the transmission. Like I said, lots of small stuff.

I also made up new set up wires to connect the starter - due to some ugly hot-start problems in the past I run a separate negative cable from one of the starter bolts up to a common ground point on the alternator bracket. The positive cable goes up to the fender-mounted Ford-style solenoid I run as the rest of the hot-start problem solver. For the curious, this is part of a kit sold by several companies and it includes a metal plate on the starter that connects the large wire to the normal small solenoid wire so that the GM-style starter operates like a Ford one-wire starter. Very slick, and works like a charm. I also took the time to fix a long-standing problem with my cobbled together throttle linkage where the nut that held the whole thing together would loose up and fall off every few thousand miles. I simply drilled a small diameter hole through the threads out near the end and inserted a hitch pin so that the nut can't back off the threads unless the hitch pin is removed. It looks like it will do the trick, but I'll have to wait a few months to find out how well it's really going to work. I got everything all ready to hook up, and put a trickle charger on the battery to make sure it was all set to go when I want to fire up the truck. It was a good thing I did - it turned out that the battery was fairly run-down from just sitting there for so long.

I filled the cooling system with straight water - I don't want to use antifreeze until it's all broken in. Why? I'll back-flush the motor it after it's been run a few hours to flush out the crud and machining dust that's left and then fill it with the proper 60/40 mix. After I filled it up, I pressure-tested the system with my handy cooling system tester and found out that the freeze plug on the passenger's side front of the block (pictured below) leaks slightly. I am really not amused with the machine shop that did this work, but it should hold enough to break in the engine; maybe the heat-cold cycling will help seal it. At least it looks like it's accessible enough to change it out while the engine is in the truck. A pain, but fixable. I still need to call the shop and complain (again) about the work they did. Between this and the balancer bolt debacle let's just say that it's been an adventure.

Note that the distributor itself it not installed until just before I will fire up the motor. I'll do one last pre-lube, then stab in the real distributor, hook everything up, and fire the motor up. Also, I opted to only put the belt for the alternator on the engine for the initial start-up and cam break in. One less thing to screw up and one less noise to worry about when tracking down any problems that happen. Same for the AC setup. I'll install the compressor after the engine is running correctly and broken in. I do need to install the power steering belt before I can drive the truck though - I've driven it sans power steering before, and it's a real back-wrenching experience. (Can we all say "daily chiropractor visits"? I thought so. :-) I did run into one hitch while trying to make sure I could pre-lube the motor once it's installed - my drill hits the firewall and I can't get it onto the shaft of the pre-lube tool. I had to go up to Harbor Freight and buy a right-angle attachment for my drill. But, to make it work, I had to grind down the shaft on the pre-lube tool so it fits in the 3/8" chuck on the right-angle attachment. At this point I had nothing left to do but lube the motor, stab in the distributor, hook up the ignition wiring, and turn the key. If all went well, the motor would come to life and I'd be able to break it in. If things went badly, I'd have gotten a big Visa bill with lots of amusing photos and a great story to tell here. If it had blown chunks on startup, I'd have been sure to get pictures of the carnage. Want to know what happened? Read on to find out. :-)

 

Cam Break-In

Before doing the break-in, I decided to be safe and hooked up the garden hose to the back-flush fitting on the heater hoses. I left the garden hose running (and pumping cool water through the engine) during the entire break-in process to help ensure against overheating. Even that wasn't enough. It made it, barely. It's still not right, though. Read on for the gory details.

It fired right up and ran bearably - so I set the idle to 2500 RPM and watched the clock to wait out the 30 minute break-in period. It got hot fast - real fast. Two header tubes were starting to glow within 10 minutes! I kept playing with the mixture and hunting for vacuum leaks. I found a few leaks (hoes that had fallen off while playing around pre-oiling the engine and installing the distributor) and got the mixture set a bit better, but it was still way too hot. Hot enough to actually melt the plastic wire connector for the temp sender - it dripped off the engine and landed in a molten pile of goo on the driver's side motor mount. (I can't get a decent picture of it either - it's a black plastic lump on a black painted metal piece in a dark area of the engine compartment...)  The heat from the exhaust also had the side effect of melting most of the sludge and slime on the trans tunnel and frame and causing it to drip off the truck and onto the driveway - kind of like a self-cleaning over burns off any remaining crud. Anyway, I grabbed a couple of box fans and set them in the engine compartment pointed down on each side of the engine, backed the idle down to 2000 RPM, and made sure the garden hose was going full blast. (Amazingly enough, the water coming out of the radiator was still about 90 to 100 degrees at the end of the break-in.) That helped keep things from hitting critical mass and melting down. Oil pressure stayed high throughout the process (50 PSI or better) but I couldn't keep an eye on the temp because the sender that was in the remanufactured head I got was busted, and I had not replaced it with my known good one from the old head.

After the break-in, I shut down the engine, the hose, and left the fans going for a while to help prevent heat soak from doing nasty things. Nothing but the temp connector had melted, and nothing blew up. So far so good. I turned off the fans after about 15 minutes, packed everything up, and left the truck to sit overnight for a full cool down cycle. The machine shop said this is very important with "moly" rings - you need to break in the engine, then let the engine fully cool before driving it at all. Without doing this they said the rings won't "set" and can flake apart, resulting in a real mess.

I came out the next day, and fired up the engine while running the garden hose again. It fired up as good as it did during the break-in, so I proceeded to try and give it a basic tune-up. I set the timing, idle speed, and mixture - but I couldn't get it to idle below 1000 RPM in neutral, and it died every time I put it into drive. I did some brainstorming with my father in law, some friends, and all of my manuals. I figured the valves were too tight, my father in law said there was a blocked coolant passage in the heads somewhere or something else causing the "super hot" problem, and the manuals were inconclusive. I had bought a set of cheap valve covers to slice up and use as oil deflectors so I could adjust the valves while it was running, so I did just that. Man, were they ever tight. A couple may not have ever been on the valve seats when the engine was running and the lifters had pumped up. (Yikes!) It was an oily smoky mess, but it helped a good bit. I could get it to idle at 1000 RPM in gear, but it was still pretty rough. It was also still running way too hot.

I puzzled over this for a few days, and decided to install the known working temp sender and fix the wire where the connector had melted. (I cut the wire off at the melted blob and installed a new connector.) After thinking about how the vacuum gauge had been jumping around at idle, I decided to put new plugs and wires on it as well. The plugs may have been gapped too large and upon closer inspection, the wires had started to burn through in a couple of places due to the excessive heat. This round of work helped out a good bit - the vacuum gauge was steadier and I could get it to idle at 900 RPM in gear (though that was still 1200-1300 RPM in neutral) and it would run enough to drive it. I was now able to get a temp reading on the engine, so I filled it full of plain water and put the radiator cap on to see if it would overheat or not - it was fine now. One more problem solved.

 

Initial Engine Break-In

Next up was that I needed to drive 40 or so miles, then give the engine 6 moderate throttle acceleration/deceleration cycles then 2 hard throttle acceleration/deceleration cycles. Before I could do that, I had a nearly empty gas tank (it was right on "E") and I needed to go get some gas. I was having trouble getting the trans to get into gear - it was probably low on fluid by now. Some of the seals leak slowly and it has been sitting around for almost 8 months by this point. I was too busy to think of this, so off I went to go get gas. What was in the tank was probably half varnish by now, so 20 gallons of premium should help things out a bit. I made it there OK, but the engine had zero power and seemed to "load up" badly just off idle until about 2500 RPM. I checked the trans fluid at the gas station and it was not even registering on the dipstick. (Oops.) I drove home and filled the trans up - and things got much better on that front. It snapped right into gear and actually ran a bit better in gear. I took it out for an around the block run, and it seemed to drive better, though things were still clearly not right yet. I took it home to cool off and so I could ponder through what it had done on the short road trip.

After a few days of thinking and few more days of messing around with it in the driveway, I decided to recheck the mixture and timing and then do the initial 40 miles or so of driving to do the next bit of the break-in process. Then I could then change the oil and see what was up next. I also called the machine shop in this time and asked them for the cam information (no cam card came in the rebuild kit - go figure) so I could get a baseline on what to expect out of the engine if all was well. They again said that if I could get the truck down to them, they could check things out and see what was up. The drive went OK, but it still loaded up badly below 2500 RPM, but had decent power above that point. The secondaries would not open (probably plugged passages in the carb from sitting), and vacuum was low at idle and during low-rpm cruising. Higher-rpm cruising and decel produced normal vacuum readings, though. Also, my aftermarket vacuum gauge decided to get sticky and not work right (I paid $15 for it used 2 years ago. I got my $15 out of it... :-), so the readings I got were less than reliable, but they were consistent. (I ordered a new gauge to replace it with the next day, when it gets here I'll install it and get some better numbers.) It also did some really weird things when it wanted to shift - I think the vacuum was so low the vacuum modulator on the trans got badly confused and wigged out.  The vacuum line to the trans is still on and has no apparent holes in it, so that appears to be fine.

The engine sounded good and didn't blow any smoke. No rattles or odd noises, good oil pressure, and the temp was rock-solid the entire time. This all indicates I got the bottom end together correctly, and the fact that I had power over a certain RPM points to fuel and/or ignition problems as my next problem to fix. No leaks, either. Even the cooling system stayed topped off - no leaks there. I changed the oil the next day, and other than the fact that the gasket on the oil filter had vulcanized to the new paint on the block due to the heat and the filter was quite stubborn to remove, all was basically well. The oil came out with gray swirls in it - not gray like when you have water in the oil, but gray like assembly lube, small particles from the cam break-in (I understand this to be normal), and what I can only guess is more machining dust I did not manage to clean out during the rebuild process. (It looked kinda like gray metallic paint.) I filled it up with fresh oil and a new filter and called it good. I had to move it around a bit while juggling cars between parking spots in the driveway, and it ran pretty good. Still loading up, but it was running better. Idle vacuum was hovering in the range of 10 inches in Drive and was steady. That said the engine internals were good and the ignition was doing it's job correctly, so that was good news. It still liked to stall out when you put it in gear, and something wasn't right so I parked it again to ponder my next steps.

 

Final Tuning and "500 Mile" Engine Break-In

At this point, I was somewhat out of easy ideas. I knew the carb needed a rebuild - it's a used Holley 600 cfm vacuum secondary carb I bought about 6 years ago for $75 and tossed on the engine without any more than a quick hosing down with carb cleaner and snugging up on the front fuel bowl screws. It was due for a going-through, so I ordered a rebuild kit and a secondary spring quick-change kit from Jegs and waiting for that to arrive. I also had a theory that the float level might have been too high in the front, or that there's crud in the needle and seat valve hanging things up. I played with the float levels before I took the carb off, but no luck. I also played with the secondary idle setting (you have to take the carb off to play with so it's a pain in the you know what...), but that actually made things worse! Ugh. So much for my idea that it was getting too much fuel... (Opening up the secondary idle setting adds more air and leans the motor out.) Idle vacuum hovered between 10 inches and 7 inches in Drive depending on which specific thing I tried, but it was too low - something was still not right.

At this point I was out of ideas and did the carb rebuild thing. Pretty basic, but I did add the "quick change" kit for the secondary springs so I could tune them a bit better later on. After putting it back on (and finding out I had shredded one of the o-rings on the transfer tube causing a major fuel leak at first. :-) and getting the basics re-set - I found there was little to no change in things. Hmmm... I went through the routine of playing with the secondary idle screw (since I had disturbed it before and while it was being rebuilt) and settled on it being about 1/4 to 1/2 of a turn in past "just touching" the idle lever. This put maximum adjusting on the primary side of the carb and I was able to do the usual set the mixture screws routine and get it running decent enough for another test drive.

The test drive was pretty uneventful but I did learn some stuff that helped me move forward. It still had no power at idle and off idle, though it was running right (no backfiring on decel even in gear). The real interesting things was that if you stomped on it over 2500 RPM, it took off real nice. Flooring it from a standing stop resulted in almost no activity (not a bog, just nothing more than more idling!) for a few seconds and then a slow and steady acceleration. After 2500 RPM or so it woke up, but something still wasn't right. No backfiring, no burps, but I still thought I had a fuel problem so I went back home for more playing around and pondering. Idle vacuum was about 11 inches and steady in Drive. Again, still too low, so I knew that was part of the problem.

A quick look through the Holley manuals I had didn't give me anything interesting, so I decided to double-check all of my vacuum lines for a leak. I checked the front manifold vacuum port - nothing wrong there. Next was the PCV and power brake port - nothing wrong there either. I was going to check the three vacuum hoses that come off the manifold behind the carb, but on a lark I decided to check the vacuum advance port on the carb - I unplugged the hose, and the idle dropped and the engine promptly died. Huh? Ported vacuum at idle? How far did I have the idle screw set in? Hmmm. I plugged the ported vacuum fitting on the carb, gave the idle screw another twist or two in so the engine would run, then fired it back up again. I adjusted the timing by advancing it a bit at a time and lowering the idle until I had it at about 8 degrees BTDC and it idled around 900 RPM in Park. I hooked the distributor back up and to my surprise it picked the idle up about 300 RPM. I checked the idle in Drive, and it dropped to about 800, but vacuum was strong - about 14-15 inches in drive and 21 in Park. Wow - what an improvement! I took it out for another test drive and it had really woken up. I actually got the tires to squeal on a U-turn I made, something that the old motor had been hard pressed to do. (The tires are tall and fat, combined with a 4.11 rear it makes for excellent traction off the line. You could always stomp it with no fear of squealing the tires before.) I returned home and did some more playing around. I settled for a little more initial timing (about 11 degrees BTDC) and a slightly lower idle setting (1100 RPM in Park, 750 RPM in Drive) and called it a night.

 

At this point, I need to put 500 miles on it and finish my break-in process. It's good enough to drive, so a few weeks of simple driving was in order to get the needed miles on the engine to finish the break-in procedure. But, my truck is back - hooray!

 

Assembly, Re-installation, Break-In, and Related Pictures

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Page last updated 01/02/2009 01:51:39 PM