New pistons and rings needed

[Carolina_Mountain_Mustangs]

I would also be suspect of the timing chain having jumped in the past. Most engines are interference with the pistons and valves if chain jumps. The piston in the picture came out of my Dad's 302. My sister had borrowed the car and the timing jumped. He stupid husband turned the distributor to get the car running and it broke valve and stuck it through the piston sideways.

If you ever have an engine jump timing you should pull the heads and you will probably have bent valves.

The welded two piece valves used by Ford got a bad name from them breaking because of jumping timing and breaking head off. They were fine but when you start hitting the piston and bending them they break. Also floating the valves will bend them then break the head off.

This engine was junk also got into the cylinder block and was too deep to bore.

You will probably find that the valve guides in the heads for the cylinders that had valves hitting are worn out of round really bad. Have your shop check all the guides while you are into the engine. I would suggest they put in new guides or sleeve them. Of course the seats will also be bad.

David

 

[Manu Mach1]

All is more and more clear.

I found push rods bended, and head guides not round and bigger. But heads have been machined already with new guides inserted and seats machined as well plus new seats on exaust to use unleaded fuel.

I'll check tonight if was timing chain original nylon coated cam gear.

So looks like timing chain gear and sproket have been changed.



And the block number

 

[cobra3073]

All is more and more clear.

I found push rods bended, and head guides not round and bigger. But heads have been machined already with new guides inserted and seats machined as well plus new seats on exaust to use unleaded fuel.

I'll check tonight if was timing chain original nylon coated cam gear.

So  looks like timing chain gear and sproket have been changed.



And the block number

According to that picture, the block casting number is "D2AE-CA" not D0AE-CA and it was built on January 11, 1973.

So, that would appear to be a 351CJ block (based on the 4 bolt mains that you referred to in an earlier post) and it would have had the open chamber heads.

~BT

 

[cobra3073]

By the way, based on your desire to continue with the stock set-up, the information Hemikiller gave you was "SPOT ON."  Just order the stock replacement pistons for a '73 351C 4V motor.

If it was me, and the block HAS to be bored, I would go for the .020 oversized if I could find the pistons. As someone else has noted, the 351C block should not be bored more than .040 over.  Going to .020 over would give you a couple more possible rebuild options without going to sleeves in the block. 

That having been said, .030 over pistons are probably more readily available.

 

[Manu Mach1]

Stock cast replacements for the '73 351CJ are Sealed Power 425NP

https://www.fmmotorparts.com/fmstorefront/federalmogul/en/USD/Engine/Cylinder-Block-Components/PSTON-EnginePiston/Sealed-Power-Cast-Piston-(Carton-of-8)/p/P425NP30#.Wq0icujwaCo

Available here:

https://www.rockauto.com/en/catalog/ford,1973,mustang,5.8l+351cid+v8,1132995,engine,piston,5620

I place an order for those pistons at Rockauto (+0.020").

Then I need rings, also +0.020 I guess?

SEALED POWER E251KC Full Set

 

[cobra3073]

Stock cast replacements for the '73 351CJ are Sealed Power 425NP

https://www.fmmotorparts.com/fmstorefront/federalmogul/en/USD/Engine/Cylinder-Block-Components/PSTON-EnginePiston/Sealed-Power-Cast-Piston-(Carton-of-8)/p/P425NP30#.Wq0icujwaCo

Available here:

https://www.rockauto.com/en/catalog/ford,1973,mustang,5.8l+351cid+v8,1132995,engine,piston,5620

I place an order for those pistons at Rockauto (+0.020").

Then I need rings, also +0.020 I guess?

SEALED POWER E251KC Full Set

Yes, the rings you need should be .020 oversized.

However the part number you cite (E251KC) appears to be standard size.  You will need Seal Power E251K20, per my research.

~BT

 

[DK73]

Wow! That's bad [emoji50][emoji106]

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