piston and piston rings

[eyal76]

hello,
I am trying to replace the head gasket, and I thought I might as well put the first cylinder into TDC but when it goes up you can see oil go around the sides of the piston but not into the combustion chamber. Is this something I should worry about? if so how would I fix it

[18Fiatsandcounting]

If I understand you correctly, this is perfectly normal. I think what you're seeing is the oil coming up through the block as you turn the engine, and there are 6 passages where the oil comes up. 3 on the driver side, 3 on the passenger side. Front of the engine, middle of the engine, and rear of the engine. Two of those passages will have the locating "dowels" to allow you to accurately position the cylinder head on the block, so make sure that they are there and not damaged.

When the cylinder head is back in place, the oil will come up through those 6 passages and then lubricate the two camshafts (and tappet buckets and shims and valve stems and distributor gear).

Do NOT do this, but if you were to crank the engine while the head is off, you will see 6 geysers of oil shooting up. Don't ask me how I know... Makes quite a mess of your engine compartment and your front fenders.

-Bryan

[eyal76]

thanks for your response, but the oil doesn't go up through the holes in the block its level with the piston in the actual chamber

[gbsailing]

It is possible you are looking at spillage from when you removed the head. Take and wipe out the cylinder several times after rotating engine by hand. It should clean up as you are not suppling enough oil from the lower end to re-coat the cylinder walls. There should be no sign of oil showing above the rings they run on a thin film of oil that you shouldn't see.

Was the top of your pistons clean or a slight coat of carbon on them? They should of been covered with a thin coat of carbon it they were clean then you could have bad rings letting oil pass by. Were you showing any blue smoke out of your exhaust before removing head? I take it you blew a head gasket that is why you removed the head or burnt valve.

[18Fiatsandcounting]

thanks for your response, but the oil doesn't go up through the holes in the block its level with the piston in the actual chamber

I'm not totally sure that I'm following you here. There shouldn't be any significant oil around the tops of the pistons, or on the walls of the cylinder bores. A very light coat perhaps, but not much more than that.

If there is significant oil (and it's not weeping from the 6 oil pressure lines), then my guess is the same as gbsailing's: Oil spilled into the combustion chambers as you removed the head. If that's the case, clean it out as he suggests and you should be good. If new oil appears, then I'm stumped.

-Bryan

[Nut124]

a little residual oil is of no concern.

When I install the head, I place the crank some 20-30deg short of the TDC mark. I then set the cams just short of the corresponding marks. It is important not to bang up the valves when installing the head. If the piston is at TDC and cams are not set accordingly, the valves can hit the piston.

When lowering the head in place, be careful not to ding up the head with the dowels. I like to do a dry run w/o the dowels, with a spare gasket to observe and make note of correct head to block alignment. I have also used 1/4 plastic spacers on top of the gasket at front and back, then lower the head on top of the spacers. Then get a few head bolts started to properly locate the head, then remove the spacers one at a time and carefully lower the head right into the dowels.

What kind of a head gasket are you using? MLS gaskets will not blow but require a near perfect finish on the head.

[RRoller123]

I have had luck using some small wooden dowel rods, that are just a little larger diameter than the head placement dowels. Place them fore and aft, across the block. Lets you roll the head back and forth a bit, get it just right, then carefully slide the dowels out the side and the head drops in place. 2 dowels does the trick.

[Nut124]

Yes, I have used 1/4" oak round rod as well. You just want to make sure that there is absolutely no slivers or dirt on them. Want nothing in the contact between the head/block and the gasket.

[Nut124]

Yes, I have used 1/4" oak round rod as well. You just want to make sure that there is absolutely no slivers or dirt on them. Want nothing in the contact between the head/block and the gasket.

[RRoller123]

Yep, gotta be clean. A poly rod would be better I suppose. A touch of wood dust down in the cylinder would just get flushed, but a large chip between the head gasket and block would be rather poor. Just sand them and wipe them down carefully and should be fine.

[SteinOnkel]

On my other car's engine there are no dowels. There used to be a special tool that has long since become unobtainium.

What you do is you take your old bolts and cut off the heads. Grind the edges smooth and use a cutoff disc to cut a slot into them, perpendicular. Put them in place (finger tight is plenty) and slide the head over them. Then you remove them one by one with a flat screwdriver and replace them with new screws in turn. Easy peasy.

[DieselSpider]

On my other car's engine there are no dowels. There used to be a special tool that has long since become unobtainium.

What you do is you take your old bolts and cut off the heads. Grind the edges smooth and use a cutoff disc to cut a slot into them, perpendicular. Put them in place (finger tight is plenty) and slide the head over them. Then you remove them one by one with a flat screwdriver and replace them with new screws in turn. Easy peasy.

Or just use a few studs or even threaded rod.

[RRoller123]

I am pretty sure that Danny has plenty of these dowels.

Fun Imported, Vernon CT Danny O'Donnell

[SteinOnkel]

But why? It takes literally 3 minutes to make them.

[RRoller123]

It takes me three minutes to get my coat on and go out to the Lab.