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Cylinder compression Tr4


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Hi Everyone

 

Nearing completion on my rebuild, I took the car out for a spin today. The first thing I noticed is the amazing amount of torque the 4 has. It was completely unexpected but very welcomed.

 

I'm used to much more powerful cars like rolls and bentley, so you can imagine my surprise when I first put my toe down in this small 4 cylinder.

 

Although the block is untouched I have had the head converted to unleaded as well as the usual stuff. Unfortunately as the head was in a bad way I had to have 3thou skimmed off it. Much more than I would have liked or am used to.

 

So my mind immediately turned to this as to why the car seemed so as though it pulled so well.

 

Was too much skimmed off causing high compression. I checked all 4 cylinder and had 220 bang on across them all. Is this a normal reading or higher than expected. I would of thought 180 was a much more normal figure.

 

Cheers Andy

 

Attached are some more pictures. Any input is welcomed, good or bad. Suggestions are also appreciated

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Presumably this was measured with all the plugs out and throttles wide open if so then yes that is quite high so be careful of pinking. The TR 4 cylinder is well known for plenty of torque and will pull cleanly from around 10mph in top.

Stuart.

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Andy

 

Mine was 175 across 1-3 and 65 on 4 when I blew the rings on it so about 180 is right

 

Car looks great

 

Graze

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Hi just add some additional figures, my standard (I think) TR4 has 160 across all 4 cylinders (dry), give or take 5 psi. Which is what I would have expected, 220 does seem high.

 

Mark

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And I do mean 3 thou. The maximum I would ever consider on the rolls royce engines i work on is 1-2

 

....just took 42 thou off one of mine to get the compression ratio I wanted.....but then it's not a roller!

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Hi

The test was done from cold, plugs out and throttle open. And I do mean 3 thou. The maximum I would ever consider on the rolls royce engines i work on is 1-2

Cheers Andy

Why would you only skim a Rolls Royce head 1-2 thou. Are you refering to the V8 Shadow and variants?

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