What condition is my condition in?

[MopaR&D]

I know this is a common question on here, but I want to know the best route to get my Duster up and running well without spending too much money. My timing chain jumped in my 318 and to make a long story short, I now have the short block sitting on my engine stand in my garage. The heads are off and from the looks of it, will never be able to be used again due to some big-time recession of the exhaust valve seats (one of them is almost 1/8" in the port!!!) due to my running (HARD) of modern unleaded gas without any lead substitutes. I grabbed a pair of #302 heads from the junkyard that look to be in good shape and I was planning on just cleaning them up and bolting them on, but there's another issue: pistons # 2,4,6,8 all have little "nicks" about the size of a large fingernail on their faces due to valve-to-piston contact when my timing chain slipped. This makes me a little uneasy and I know it would be a good idea to just get new pistons, but I don't know if my block is in good enough shape to just drop new pistons in without a bore/hone. Can anybody give me an estimate on how much it costs to get a block bored over .030" and honed, if I need it? I know pics would help, I'll see if I can get some up with my cell phone.

 

[Backtobasics]

Don't worry about the knicks in the pistons, it probably knocked the carbon off and not much more. The heads on the valve bent on contact, it did not hurt the structure of the piston. It would take an entire dropped valve to hurt the pistons. Clean everything up, re-assemble with the 302 heads, and motor it down the road.

 

[RedFish]

The scars in the piston tops dont hurt anything. If you didn't have major compression lose at the rings just top end repair is a low budget option.
I'd put a new oil pump in it though, and freshen the coolant system as well.

 

[MopaR&D]

That's great news. Would it be a good idea to replace the rings? I'm not sure what condition they're in, but I did flood the engine numerous times due to fuel/carburetor issues.

 

[pagilman]

If your going to replace the rings you might as well replace the rod and main bearing when the rods are out. If you don't have a groove built up in the cyclinder at the top of piston travel, enough to catch a nail on, run with what you got for low budget!!!!!!!! Put it back together.

 

[MopaR&D]

There is a "ring" of material at the top of the cylinders that might be an issue if I tried to remove the pistons. I don't know how bad it is in relation to other engines of this age and mileage, though.

 

[Backtobasics]

Assemble it up, add a little oil to the cylinders, and make sure things are ready to go when it is time to fire. Light it off, and keep the RPM around 2000 for a few minutes, to let the oil get moving, and the engine get some heat and up to temperature. I think you will be ok for ring seal, especially for a budget build, and the seal will get better with time. Don't abuse it for a bit, and enjoy.

 

[MopaR&D]

By "assemble it up" you mean put in new rings, right? I just realized the purpose of taking it easy for a while, as my cylinders won't have the crosshatch pattern to make the rings seat properly. Is there any way to tell the condition of the rings without having to do a compression test?

EDIT: I think I'll just leave the bottom end alone. I did a little reading and it seems to be a better idea to leave the rings alone unless you can get a proper hone job done. And if I was going to do that, I'd probably go all the way and get it bored over with new pistons anyway.

 

[66dartgt]

Leave the bottom end together - I'd go ahead and replace the oil pump however.

To verify how bad the piston nicks are: I'd bring the pistons up to tdc each - one at a time and clean the piston tops with a razor blade or sharp putty knife. This is good practice as you may have some bits of metal that are loose there. Use a shop vac to suck up the bits of crud and clean them with lacquer thinnner or carb cleaner. When done lube the cylinders with a little motor oil. As suggested above - I'd also replace ALL the freeze plugs in the block - there are 10 of them. Main reason is that alot of gunk collects in the bottoms of the water jackets and that crud rots the freeze plugs out on old motors. Plus two of the plugs you cant even get to when the engine is in the car, they are on the rear of the block.

Not to insult your knowledge but just in case you dont know how: The plugs are easy to remove with a hammer and chisel and then a pair of vice grips to pull them out. To reinstall use some permatex #2 along the edge of the new plugs and drive them in with a socket that just fits inside the cup of the plug. Drive them in until just flush where the plug hole bevel ends inward on the block. While the plugs are out flush the water jackets with copious amounts of water (hose).

With the heads I'd take them apart and check them for any sticky valves, you can lap the seats with some grinding compound and a rubber ended hand grinding stick. Clean them as well as you can to get the grinding compound out. Keep all the valves in order and reassemble them as taken apart. You should consider replacing the springs - you could use the springs off your old heads along with their retainers. Those 302 heads probably have rotator exhaust valve retainers (not desirable), and the springs will be fairly stiff for use with flat tappet cam. 302's are used with roller cams. Put some new valve seals in and reassemble !

An alternative to the heads would be to have your local machine shop do a basic head overhaul. My shop charges 100$/pair, well worth it in terms of cleaning needed etc. Its a messy job and the parts are very tough to clean properly without a hot tank etc.

Good luck and let us know how things go !

 

[moper]

Dont touch the lower end. You will need to have machining done to re-ring it as the ridge will damage (at best) or break (at orst) the new rings. Eyebrows in the pistons are nothign to sweat. I like to shave off the raised part of the aluminum, but you don't have to. As was said, stick in new freeze plugs, bolt the heads on, and go.

 

[MopaR&D]

I think I'll send the new heads to a local performance machine shop for cleaning and inspection, and I'll be putting in new springs because I'm planning a cam swap anyway (Lunati Voodoo 256/262). I ran my fingers over the nicks in the pistons and they are barely noticeable; I think the carbon was just knocked off like another poster said. My freeze plugs are in bad shape too, I'll definitely be replacing those. Thank you all so much for your replies, they saved me much grief!