Alright, so heres the short of it. I had this car running before winter fairly well. I could hear a miss when revved, but chalked it up to needing a 1920 rebuild kit. One day I went out and tried to start her and ultimately found that I had bent pushrods.

I decided to just pull the head and work my way up, hoping that the pistons and cyls were in decent shape. The bores were not too bad, but the 3rd and 4th piston had some light brown silt, almost like crematorium ashes on them. All cylinders have a lip of coked oil about a half inch into the cylinder as well.

What is this mysterious substance, and should i just pull the motor and start from the bottom up?

As soon as I figure out how to post pics, ill post pics of the head top and bottom, and the mystery silt on the piston.

Please help!

_________________
The only way you can ever really break something beyond repair is to give up trying to fix it.

Here they are. click the link for my google picasa album and prepare to weep.

https://picasaweb.google.com/jeoffreyh/ ... directlink

_________________
The only way you can ever really break something beyond repair is to give up trying to fix it.

The silt-like powder I can't help with. It may be corrosion of the piston, but that's usually light gray. The #1 reason for bending pushrods in an older engine is bad gas. It turns to varnish and sticks the intake valves. The old gas needs to be removed and disposed of.

The band of gunk at the tops of the cylinders is carbon and oil. It's pretty common and starts where the top piston ring stops. Your deposits look wetter and thicker than some. I imagine this engine consumed a fair amount of oil.

If you want the car running again clean the fuel system. Tear down the head and clean the valves and guides. Clean the silt and junk from the cylinders. Put it back together. With fresh fuel and clean valve guides you shouldn't bend any more pushrods.

_________________
Joshua

The cylinders that have the tannish color to the chambers is likely rust(cracked head), and the head needs to be magnafluxed.

_________________
There's no such thing as too much cam....only not enough engine!

Or a head gasket leaking water.
Frank

_________________
Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

With at much "crud" in the cylinders, it is likely that the rings are plugged / stuck.
Best to disassemble and re-ring the engine while it's out & apart.
DD

The brown silt could simply be rust, either from the inside of a cracked head, or the intake has been 'drowned' from exposure to the elements. If your engine has been left with one or two valves open in the cylinder most affected, they are probably stuck because of rust. The intake channels also seem very corroded.

Olaf.

_________________
Aspenized

Now that I think about it, I believe the silt might be sediment from bad fuel or whatever was in the runners as I was trying to start it with starting fluid when the valves stuck. The oxidation on the head over those cylinders would be evidence of those valves being stuck upen and exposing the cylinder to air.

I get your point about bad gas Joshua, I can see on the valve stems where they gummed up and caused the valves to seize, bending pushrods etc. Fuel system and lines are part of this rebuild.

Should I pull the bottom end, replace pistons AND rings, or just clean her up, get the head cleaned and magnafluxed, new valve springs and valves etc and throw the head on the same rings and pistons (cleaned as much as possible of course)? This engine was at least starved of oil due to a leaky fuel pump (previous owner ran it for who knows how long like that) and could have been run for a decent amount of time like that. Surprisingly, the bores look smooth and I believe these pistons may be ok to use.

I intended on a cleanup/rebuild to stock. However, i 'm thinking I need to just bite the bullet and give this old girl the rebuild she deserves. That's going to take me a while

_________________
The only way you can ever really break something beyond repair is to give up trying to fix it.

Pistons may clean up but I would get rid of the rings. New rings are cheap.
Frank

_________________
Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

Once the engine is apart, the surface condition of the cylinders will "show you the way".
Rust pitting and / or excessive wear will require block boring and oversize pistons to correct.
DD

The pics didn't show the cylinder wall condition very well. Is there a noticable ridge at the top of the cylinders (found were the upper ring stops)? If so, remove it with a ridge reamer then measure piston to wall clearance and compair it to specs (you'll need to remove the rings to do this). That will tell you what you need to do. I always change rings and hone the cylinders as a matter of course whenever pistons are removed.

I agree with 6s\ant6. That brown coating looks like years of gas residue to me (aluminum pistons don't rust).
________
Bmw M52 History

If your going to pull the engine down do it right. A shiney cylinder bore does not mean a lot. You got your labor into this so do it right. It woint be cheap but get new pistons have it bored for the pistons replace all bearings piston rings ect new oil pump and totaly rebuild this engine. Then you will have a engine that will give you good service and last a long time. If you have the skill to do this then your money ahead. If not let someone that has this skill do it for you and you will be money ahead. This is why I doint build my race engine in my car I doint have the skill but know who has. Thanks Ron





It Aint Over Until I Win

Yeah..im pretty certain that this poor old slant ran with lots of gas in the oil for a long, long time. She deserves a thorough rebuild and I need to take my time and be patient.

I'll be around, turnin wrenches, askin questions thanks all.

_________________
The only way you can ever really break something beyond repair is to give up trying to fix it.

Had a similar problem with a 'good runner' from a wrecking yard. three inlet valves were in very bad shape from being in water for some extended length of time, possibly 5 or more years.



Uploaded with ImageShack.us

The pic is of the worst one. The solution to the problem was to replace all the valves ancheck the stems for clearance, as well as recutting 3 seats.

Wow thats pretty bad...and im sure that old slant was actually trying to run, as these slants do under ridiculous conditions. I just removed the valves, seals and springs and at least three of my valves needed much more persuading than I expected to remove them from the head.

Varnish, bad gas and an oil starved head did a number on this old girl.

Now to find an engine stand! And some more money. Probably lots.

_________________
The only way you can ever really break something beyond repair is to give up trying to fix it.