Copper Or Aluminum Spark Plug Washers For 1967 Corvette

[Timothy B.]

I have both and want to know if the 67 300hp engine used the copper or aluminum version spark plug crush washer.

TIA,

Tim

[Joe L.]

Re: Copper Or Aluminum Spark Plug Washers For 1967 Corvette

I have both and want to know if the 67 300hp engine used the copper or aluminum version spark plug crush washer.

TIA,

Tim

Tim------


I don't think they were either. I think they were zinc or chrome plated steel. GM #1555475. I don't know of any that were aluminum.

By the way, once-upon-a-time I think the 1555475 was copper. However, I think it changed to zinc or chrome plated steel by 1967.

[Timothy B.]

Re: Copper Or Aluminum Spark Plug Washers For 1967 Corvette

Thanks Joe,

I have some that stick to a magnet but look like they are copper plated. The others look like aluminum but they must be the zinc plated version. I was just wondering if there was any certain period of time one was used then a switch to the more common zinc washer.

[Dave S.]

Re: Copper Or Aluminum Spark Plug Washers For 1967 Corvette

Thanks Joe,

I have some that stick to a magnet but look like they are copper plated. The others look like aluminum but they must be the zinc plated version. I was just wondering if there was any certain period of time one was used then a switch to the more common zinc washer.

Copper washers on AC plugs ended around 1961/1962 or so.

[Perry M.]

Re: Copper Or Aluminum Spark Plug Washers For 1967 Corvette

We're not going to start judging those are we?

[Joe L.]

Re: Copper Or Aluminum Spark Plug Washers For 1967 Corvette

We're not going to start judging those are we?

Perry-------


Only judges with x-ray vision. Those guys will also judge all of the internal parts of the engine.

[Joe L.]

Re: Copper Or Aluminum Spark Plug Washers For 1967 Corvette

By the way, there were several styles of these plug washers. The GM #1555475, be they copper or zinc plated steel, are the "slip on" type. They simply fit over the threads of the plug and seat on the flange of the plug.

The later GM #5612328 which are zinc plated steel have three "dimples" on the ID. These serve as "threads" and require the gasket to be threaded down the threads of the spark plug. These "dimples" need to be trimmed off when these washers are used on long reach spark plugs. Long reach plugs have an unthreaded section between the threads and the seat (e.g. AC 43N used on big blocks). So, if these gaskets were used as-is, the "dimples" would prevent the gasket from reaching the seat. The GM #5612328 remain available from GM to this day. If gasketed plugs are removed and re-installed, it's a good idea to replace these gaskets since these are a "crush-type" gasket.

[Timothy B.]

Re: Copper Or Aluminum Spark Plug Washers For 1967 Corvette

Joe,

The washers I have are the dimple type so they must be 5612328.

[Joe L.]

Re: Copper Or Aluminum Spark Plug Washers For 1967 Corvette

Joe,

The washers I have are the dimple type so they must be 5612328.

Timothy-------

I have seen the 5612328 in both copper and steel. Like the 1555475, at some point these changed from copper to steel but I don't know just when that was.