OK, so I did a real stupid thing (I think) I'm not sure but I think I must have dropped a washer in the intake manifold and not known it, yup, you guessed it, I started it up after pulling the carb and this lovely metalic erratic rattleing sound, came, went away, came back.. Pulled the carb, fished around with a magnet, put it back on, tried again...the erratic mechanical metalic sound, like some small metal thing whirling around suddenly stopped, and turned into a loud regular metalic calck-a, clack-a, clack-a, clack-a... My guess it something wedged in a valve? Its just a guess, I have no idea.. What else could it be?

Well, Tonight I pulled the intake manifold just hoping to find a hunk of something I could pull out, no such luck.

So, what was that noise? Do I pull the heads? Could it be a lifter gone bad? What is the procedure for pulling the heads on a 302? Do I mess with the valve adjustment before pulling? is there a sequence for loosening the head bolts? Tightning? What does a valve job cost? Lifters, whats a new set cost? What the heck sould I do???

Yup, Im lost.... Its been about 20 years since Ive done this, I could use some advice, encouragement, help.. This is my ride to work so I need to get her going sooooon!

Any advice appreciated!

 

Oh crap. You will need to pull at least one of the heads. The side the noise came from. Since it started making noise right after you lost a washer I would think that it is in a cylinder. Stuck in the side of one of the pistons I would guess. Just remove the rocker arms. Keep track of the placement of everything so all the pushrods go back in the same holes. Then remove the head bolts the reverse of tightening. You probably need a manual. $20 bucks. Loosen head bolts from the center and work your way out to the ends. Hopefully your block isn't ruined. Gota go. Will check in later.

 

Well, I sure could use some advice on next steps.. I pulled one head,I did find a chunk of steel, about 1/3 inch long, 1/8 inch wide..I all but certain it never was a flat washer..

I dont know what it is or where it came from?? I have no way of knowing if there is anything in any cyls in the other bank, but I do not suspect so.

So, I see no damage to a valve, but I suppost I at least should pop out the intake and look at the seat??

Now the piston top, that has some smushes, none look very deep, how thick is the top of a 302 piston? the piston top, at the edge is a bit munched but I do not think anything went down the side and the cyl wall has only very faint scratches that look much like the other clys do.

What sould I do? Do I need to replace the piston? How much damage is ok to run?

Appreciate all your help! Im a bit lost, its been 20 or so years since Ive done this stuff..

 

Well, if you are following the story here is more... I am very carefull, but indeed I did drop a washer from the carb bolts into the manifold. The odds are small, that if one washer falls off, you cant find it, that it fell in one of those little holes, hell, its only a 2bbl... But it did. So, I pulled the other head and two more chunks of washer were in another cyl. So, heads are going in, valves must be dammaged. Two pistons have marring on the tops, I do not know what amount is acceptable so I am trying to find someone in my area to have a look at pistons and cyl walls... Crap, please learn from my mistake, watch everything!
Can I replace 1 or 2 pistons by pulling the pan and sliding them in and out? bit of a hone and new rings?

 

You were smart about not running the engine too long so the damage is low. I'm not sure that you need to repair anything in the block. If you don't have deep scratches in the cylinder walls or broken pistons then you might leave the pistons alone. If you don't remove the pistons then I would use a magnet with a metal finger stuck to it to run around the edge of the pistons to search for any metal pieces. You also might move each piston to the top and pour a little oil all around the edge of the piston. Then move the piston down. If there are any pieces of metal or fines they will stick to the oil and then wipe the cylinder walls clean. This is a good time to check engine life. Do you have a big ridge at the cylinder top edge?

The heads. Each valve will need to be inspected. The metal might have damaged the seats of the valves but I wouldn't worry about a few dings in the chamber. You can grind them down if they look like they could shed metal. This might be a good time to rebuild the heads. Do you know how many miles are on the engine? If there aren't any valve problems you might be able to put his thing back together.

 

There is no ridge in the cylinder at all, must be pretty fresh. The issue I suppose with the pistons is that the damage is right at the edge by the cylinder wall, difficult to grind there, perhaps I can carefully scrape anything loose off?? How much of a scratch is OK on a cylinder wall? I am going to have the heads done, for a couple hundred its worth it. a flat washer was ground into 3 chunks, I imagine the valves are what did that? Must be some damage. I dont suppose anyone out there is near Eugene Oregon and might have a quick look at the pistons?

 

you should be ok with the pistons.i wouldnt do the valves just yet.all you need do is take them apart and inspect them.any damage can easily be seen.just keep everything in order.

 

Doing the heads is up to you but it sounds like the engine is new from the ridge. The heads could be new also. You might ask a shop if they will just inspect them. The valves don't really apply pressure like a piston. They just open and close. If something gets in their way they just don't close. My guess is that you won't find any problems with them after only running a short time. The shop could do a quick lap job and be done. The piston and heat is what mangled the metal. Smacking from the head to the piston. Scratches, Hmm... if you run your finger nail back and forth and cut some nail then there is a problem. Small scratches the rings can sometimes fix. A digital camera might give us a look. The scratches are probably best left alone. If you can stand on your head then the burr on the piston might be fixed with a razor blade. Trap all shavings of coarse and clean the piston upper with oil again.

 

Here are some photos, please look in my gallery for more shots. Any marks on the cylinder walls are reflections, there is only one slight scratch that bairly catches a fingernail at all.. How bad are these pistons? Should I clean them up and run it? The lighting makes shadows that are a bit more dramatic than real life, but look at all the shots to get a good idea. I appreciate all your assistance and opinions very much. I do not hot rod this truck, just a driver to work every day.

link to photo 1

link to photo 2


PLease see my gallery for more..

 

Nice truck. I remember when I was about 10 years old helping my dad rebuild a flathead in rig just like yours. We broke off 3 or 4 head bolts and had to drill and ez-out. Bolts were junk back then. Saw your picts and I think you got lucky. The cylinder walls look good. The marks on the pistons will heal after some combustion. The high points will melt down just a bit and the grooves will fill up with carbon deposits. This might sound bad but that is what pistons do. It's OK.
When the heads go on, clean and wire brush the head bolts. Just before you install the bolts apply a light coat of thin oil to them. They should be wet but not dripping. This will give the correct torque. Check the head gasket for the correct side up and on the correct side. This stuff is labeled pretty well.

 

Thanks for the advice and the encouragement, this is getting pretty depressing... I am having the heads done since they are off, I am linking to a diagram with one final bit of info, just trying to be complete in my description, if you could have one more look and I sure trust you opinion, sounds like you have been into these a few times, Thanks very much again..

diagram

 

I zoomed in on your picts and see your diagram. In operation the piston above the rings never touches the cylinder. The rings keep it pushed away from the walls. It's hard to see exactly how deformed the piston is but the bevel isn't important. If I had to assign importance it would be mostly, is there metal sticking out the side that would rub on the cylinder wall or sticking up that would hit the head. You will have to gauge that yourself. You can bring the piston to the top and measure how much it sticks up. Then measure the distance in the head. You might also try setting the head on without the head gasket. Not sure if they should collide. If they don't then you got it made. In your diagram you really didn't show the gap between piston and cylinder and if metal sticks out the side. If you are too concerned then pull the pan and pop out the bad pistons and do a little grinding on them. You should be able to pop the pan and get them out in about 4 hours. The biggest hassel is getting the pan off most of the time. Since you don't have a ridge the pistons will slide right out and then back in with a ring compressor. None of this stuff is very hard, you just mark all of the pieces before you tear down. If you are careful you could remove the rod cap and push the piston up just enough to work on it without poping the rings out. This would take some help. Then you could tape off the area and work clean. Keep those cylinders covered up when the heads are off. Don't wont dust and dirt in there.

 

The metal does stick to the side to the point where bits of it are touching the cylinder wall. I do not think it goes high enough to hit the head at all. If a little alluminum touching the wall is pretty harmless I'd perfer not to pull the piston at all, but if you think that bit of scrape will cause problems, I like your idea about pushing up enough to "dress" it without even poping out the top ring. Still, leaving it alone sounds better. Will the bit of scrape likely be an issue? Or will it wear away and in a sence correct itself?

Thanks!!

 

Remove the pan. Get the piston all the way to the bottom. Mark the rod cap or note the numbers on the ends if they have them. It needs to go back on the same way. Remove the cap and slide some rubber hose on the bolts so they can't scratch the crank. Turn the crank until the piston is at the top. Up on the top of the block use a head bolt and some spacers, washers, whatever to build a stop for the piston. The idea is to allow the piston to come up a small amount and no more. Maybe a tenth of any inch. You should be able to push the piston from the bottom with a gentle tap. Then clean around the piston and apply tape so metal can't get into the cylinder. Get out the dremel. When finished, clean up and remove the tape. Push the piston back down until it hits the crank. Then you can turn the crank a little and push the piston down. Repeat until the rod is back at the bottom. Replace rod cap and torque it down.

 

I wanted to add something to the piston fix. Pushing the piston up without damaging the top ring is guaranteed only if your ridge in the cylinder is zip. You also might want to clean the carbon from the ridge area.