Some of you may remember that I had diagnosed a bad exhaust valve in my '52 228 GMC 6. Saturday morning my brother Tom and I started tearing the head off of the engine in order to have (hopefully just) a valve job done. The only real problem we ran into was that the radiator needed to come off first. There wasn't enough space between the radiator and the fan to remove the fan bolts. Started searching for the drain cock on the radiator (new aftermarket radiator installed by previous owner's shop). No drain! Couldn't get to the bottom radiator hose to pull it off to drain because A/C was in the way. Finally opened the drain cock on the driver's side of the block and let that drain until it quit, but only got about a gallon. Book says 4.5 gallons (with the original radiator). so we had a long way to go. This is because the water pump is so high on the engine, effectively preventing most of the radiator from draining through the block. Stuck an air hose in the radiator filler neck with a rag wrapped around it for a seal. Regulated the air at about 10 PSI and that blew the water from the radiator uphill past the water pump, back down into the block and out through the drain cock. Got a little over 4 galloons before air started coming out. Removed the radiator which probably had another pint of coolant in the bottom. Interesting find, and I wonder if all the water pumps are like this .... One of the 4 bolts that hold the water pump to the block cannot be completely remove from the pump without removing the pulley (it is a press fit) from the water pump. On my truck, this one hex-head bolt had a screwdriver slot machined into it, making it much easier to loosen in its tight space. Return fitting on the bottom of the oil filter was a little tricky to remove. We were afraid that we were going to tear up the hose trying to unthread it until we realized the easy way was to hold the fitting with a wrench and just turn the oil filter canister. Once we got the head off we found these markings on the cylinder wall of #6 cylinder and to a lesser extent on #5. It just seems to be a discoloration. Any opinions out there as to what causes this? Am I stupid to just do a valve job? Boring and getting new pistons for a 228 is probably about the same money as rebuilding a 270 or 302. Cylinder walls are nice and smooth with a ridge on the top that is barely detectable with a fingernail. Engine is standard 3 9/16" bore size. Next we pulled #5 exhaust valve and found this ... and this ... which confirms the trouble shooting analysis that Ken and I did a month or two ago. We also found cracks in the #4/#5 port of the exhaust manifold. So the question is, do I do the valve job, find an exhaust manifold and stick it back together or find a 270/302? The engine runs at reasonable temperature and carries good oil pressure with no unusual noises other than the "putt" sound every time cylinder # 5 fired.
Well Bill ; Me , I'd drop the pan and push out the pistons , fit a nice set of ' gapless ' piston rings and unless those old pistons were near *perfect* I'd scrap them too , have the connecting rods rebuilt and then balance all the various bit to zero grams or as close as one can (mix & match for the initial balancing) then re assemble with dry cylinders & pistons , break it in in 60 seconds then drive it 'till I'm dead because that's how The Generous Motors Corporation designed it to be done , your truck is old enough to show they knew *exactly* what they were doing when designing and building your nice old light duty truck . I assume you're going full monty of the head , right ? .
Drop in a 350~ Yeah, that one bolt is an interesting deal, huh? I haven't bought one forever, but does a new pump come with the pulley? Great pictures Bill.
The machine shop says I should try to find an exhaust manifold. I'll post in the "parts wanted" section too, but I'm in the market for an exhaust manifold for a '52 GMC 150-22. I cannot read the number on mine (the cast iron eating moths have attacked it), but the intake manifold is 2184002. Parts Book says the matching exhaust is 2184001 and to use 6107379 when those run out. This is for the cylinder 4 & 5 exhaust port:
I cleaned up the front of my engine this morning. Down in all the gunk I found this clamp, held on by the top bolt of the timing gear cover. It had the remains of a braided cloth hose in it, cut off flush on either side. Hose OD was around 5/16" with an ID of about 1/8". Any idea what the original hose was for? As long as we are talking hoses, I should probably replace the oil filter return hose. I haven't started looking yet, but if you have 1st person knowledge of one that fits I'd appreciate knowing where you got it.
Maybe the previous owner dropped the original bolt, found that one laying around somewhere and decided to install it just to screw with the next owner's mind~ I know I'd never do anything like that... I'll check my 228 and see what I have there tonight.
I'm new to this, but I just bought the short water pump from our host and it does come with a new pulley. As for the 1 bolt at the front with the braided hose, I know some back yard mechanics that would put the metal gas line in a tiny piece of braided hose to keep it from rubbing. Just a guess.
Another question Now that I've left Marvel Mystery Oil sitting on top of the pistons the carbon deposits are much softer. Should I remove them the best as I can? What tools should I use? I'm guessing not a sharp scraper because I don't want to nick the metal of the piston (or worse the wall or top of block). I scraped some of the gunk off of the top of #2 piston and found that this engine truly does have original pistons in place, along with the previously mentioned very small ridge at the top of the cylinders. According to the Maintenance Manual, the 2 on the top of the piston specifies that this piston was in #2 cylinder from the factory and the 3 on the top of the piston (hard to see, a little over an inch to the right of the 2) matches the Bore Size Selection number 3 on the top of the block. It is very possible this is the first time since the factory these pistons have seen the light of day.
Nice, Bill! Maybe a job for my 3M wheel? Those things will take it down in no time! That, or put it back together, run it 'til hot and then introduce the water trick that Nate has mentioned? Your giving me ideas here. Again, great photo!
I'm not planning to pull the pistons. This suggestion and Zig's sound like to big a chance of crud flying unseen into the wrong place to me. I found a hard plastic 1.5" putty knife at the local hardware store yesterday. I think I'll just scrape off what I can, shop vac the cylinders and call it a day.
Well, if it's flying into unforeseen places, you won't know it's there~ Seriously, you ought to give the 3M wheel a shot.
BTW, I checked to see if my 228 had a clamp like what yours does at the top of your timing chain cover. It doesn't. The mystery continues.
Years paste when I did what you are doing I just moved each cylinder to the top taped off the other areas and there was no crud flying into the wrong places. The plastic knife seems like a great tool to use hopefully the MM oil has all the buildup softened.
It looks like the valve seat can be saved. If not have the shop install a Stellite seat which handles the swamp water they call fuel now. Lead both lubricated and cushioned the valve to seat pounding. Laquer thinner will often loosen the carbon deposits by disolving the varnish like binder which makes scraping off easier. 302's are getting scarce so let me know if you find an extra one. I have a military one but would like a civilian issue.
Talked to the machine shop today. They are replacing all the valve guides and exhaust valves. Head magnafluxed OK. I found another exhaust (and intake) manifold to replace the cracked one that was on the truck.
Off topic a little... I had a visit from a couple of Characters today. Thought a photo or two might be appropriate... Enjoyed the visit Ken and Bill. Had a good lunch at Whataburger, too.
BTW, for those of you who don't know, I'm the good looking one! Bilbo, your truck looks awesome! Here's one more shot for those who like truck porno! Nice rearend! Thanks for a fun day guys! Ken
