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Do you know cc volume of this Piston?


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Hi Guys,

trying to calculate compression ratio of my 1970 351c 2v engine .

 

I got all info to calculate comp ratio except piston volume. Pistons are .60 over

They look like this:

s-l500.jpg

 

Do you know cc volume of this Piston?. Any help would be appreciated.

 

I googled internet but was unable to find this information

thanks

Alex

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I think those are federal mogul. If memory serves me correctly they are 7-8cc including the valve relief.

73 Grande H Code. Headman long tube headers, T-5 Transmission, 3.70 Traclok, Lowered 1" all around, Aussie 2v heads w/ 2.19 intake, 1.71 exhaust, screw in studs, full roller cam 608/612 lift 280/281 duration LSA 112, Quick Fuel 750 CFM double pumper, AirGap intake.

 

- Jason

 

 

082-hot-rod-power-tour-2017-1970-1970s.jpg

 

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I think those are federal mogul. If memory serves me correctly they are 7-8cc including the valve relief.

 

Hi 73Pony

 

Thank you very much for help.

I would of bet my life that these are over 15 cc's . I mean, there is a dish area + valve relief + .60 over...

::thumb::

Alex

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Do you have the heads off? Cut a piece of plexi glass to fit over the top of the piston. Drill two holes in it. Get a syringe and fill it with a know amount of water with some food coloring in it. Starting adding fluid under plexi glass through one of the holes until all air is out and it is full of the fluid. Look at how much you have left in the syringe. Subtract the starting volume from the ending volume and that is the volume of the dish in the piston. The FM .60 over Pistons are 8 cc.

73 Grande H Code. Headman long tube headers, T-5 Transmission, 3.70 Traclok, Lowered 1" all around, Aussie 2v heads w/ 2.19 intake, 1.71 exhaust, screw in studs, full roller cam 608/612 lift 280/281 duration LSA 112, Quick Fuel 750 CFM double pumper, AirGap intake.

 

- Jason

 

 

082-hot-rod-power-tour-2017-1970-1970s.jpg

 

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Probably 13-15 cc's. Pretty hard to build compression with that piston, why are you choosing to use it?

http://www.7173mustangs.com/gallery/1_01_07_15_8_53_18.png

 

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!

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Only accurate ways is like has been suggested. Do an actual physical check. If the block has not been decked there will be variation from end to end and side to side. The heads can also vary due to casting variation and machining variations. You should check all 8 cylinders and the heads also. That is if you want to know how accurate and exactly what your compression is going to be.

I made a set of angle plates that bolted to the ends of 289 heads when were building them with 14 to 1 compression. Would set up on surface plate and use dial indicator to get the best average for the depth of the combustion chambers and surface grind the heads. Of course the blocks were decked on the crank. No head gaskets were used the heads were lapped to the block. We did not have CNC mills back then so we hand ground the chambers to equal CC. Those engines ran chills down my spine to hear them scream. Some guys would take them over 12,000 rpm. At idle they just sound so crisp.

I saw one that blew and separated the block right down the center of the cam bore.

I have everything to built a 13 - 1 289 I have had for 30 years hope to do that over the winter for one of the 65 verts.

Just check it. It is usually better to use light oil even mineral oil and not water so you don't get rust issues.

When a man is in the woods and talks and no women are there is he still wrong??:P

David

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Do you have the heads off? Cut a piece of plexi glass to fit over the top of the piston. Drill two holes in it. Get a syringe and fill it with a know amount of water with some food coloring in it. Starting adding fluid under plexi glass through one of the holes until all air is out and it is full of the fluid. Look at how much you have left in the syringe. Subtract the starting volume from the ending volume and that is the volume of the dish in the piston. The FM .60 over Pistons are 8 cc.

 

Yes. I got the heads off. The engine is still in the vehicle. I tried doing exactly what you suggested but was not successful. I will repeat again.

Thanks for your help

Alex

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I'm going with 15 to 18 cc. A single valve relief is about 3cc, two valve reliefs are about 7cc.

Thanks Don.

Probably 13-15 cc's.  Pretty hard to build compression with that piston, why are you choosing to use it?

I don't have any choice. 

This is the engine that came with the car that I bought last year. 

I removed the heads and old camshaft. Just wanted to get an idea of the compression before I put it all back together with new replacement cam.

It looks like compression ratio is around 7:73:1 ::shrug::

 

Anyway, i already have another engine ready for rebuild (its 4v with popup pistons that will give me about 10.5 compression with open chamber heads)

 

I'll start another thread about that build...

Only accurate ways is like has been suggested. Do an actual physical check. If the block has not been decked there will be variation from end to end and side to side. The heads can also vary due to casting variation and machining variations. You should check all 8 cylinders and the heads also. That is if you want to know how accurate and exactly what your compression is going to be.

I made a set of angle plates that bolted to the ends of 289 heads when were building them with 14 to 1 compression. Would set up on surface plate and use dial indicator to get the best average for the depth of the combustion chambers and surface grind the heads. Of course the blocks were decked on the crank. No head gaskets were used the heads were lapped to the block. We did not have CNC mills back then so we hand ground the chambers to equal CC. Those engines ran chills down my spine to hear them scream. Some guys would take them over 12,000 rpm. At idle they just sound so crisp.

I saw one that blew and separated the block right down the center of the cam bore.

I have everything to built a 13 - 1 289 I have had for 30 years hope to do that over the winter for one of the 65 verts.

Just check it. It is usually better to use light oil even mineral oil and not water so you don't get rust issues.

Thanks

It is a bit difficult to do this with the engine in the car. I'll try again.

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I'm going with 15 to 18 cc. A single valve relief is about 3cc, two valve reliefs are about 7cc.

 

I'm with Don C, 18cc. They look  like cast "rebuilder" pistons to me. If they are, they likely have a decreased compression distance which would lower the compression even further. Chuck

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

I used these, about 8cc. On my engine they also gave me .030 deck height which dropped the compression a bit more from what I expected. I'm at 9.9 static compression with a 62cc head and .027 cometic gasket on a .030 over block.

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  • 2 weeks later...

you could use a bit of modeling clay on top of the piston and flush with the deck (With the piston at the top of the stroke) to determine the actual volume. Just put it in a container and measure the volume of liquid with the clay in place, remove the clay and measure the decrease and you have the volume.

http://www.7173mustangs.com/gallery/1_01_07_15_8_53_18.png

 

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!

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