Tear Down and Reassemble Unstarted 1.7 built to 2270, 1.7 to 2270 Unstarted 10 Year Old Build Options

[Superhawk996]

I was targeting around 9 C/R. If I went with the larger available .160" shims from type 4 and did not grind them, my deck height would be .08' and compression ratio of 8.8. Is this C/R too low for my motor?

I might be tempted to live with that.

Like you I’d rather have the higher compression ratio and tighter quench for combustion efficiency. The counterpoint is you are using cast iron cylinders and your engine is going to be running hot vs a Raby style build using Nickies. Plan on an external oil cooler. But lowering the compression will help run a bit cooler. In the end it may be a wash. Giving up a little HP for less heat, more longevity.

I’m a little surprised that it would still be 8.8. Have you cc’d your heads and valve pockets to be sure you are calculating Compression Ratio accurately?

[emerygt350]

I would go for the lower compression and just tell everyone you are going to put a turbo on it.


And then put a turbo on it.



And on a more serious note, I am only around 8.6 - 8.8 on my 2056 and the heat is real. However, you probably have a raby cam so you should be in better shape.

[Robroe]

I was targeting around 9 C/R. If I went with the larger available .160" shims from type 4 and did not grind them, my deck height would be .08' and compression ratio of 8.8. Is this C/R too low for my motor?

I might be tempted to live with that.

Like you I’d rather have the higher compression ratio and tighter quench for combustion efficiency. The counterpoint is you are using cast iron cylinders and your engine is going to be running hot vs a Raby style build using Nickies. Plan on an external oil cooler. But lowering the compression will help run a bit cooler. In the end it may be a wash. Giving up a little HP for less heat, more longevity.

I’m a little surprised that it would still be 8.8. Have you cc’d your heads and valve pockets to be sure you are calculating Compression Ratio accurately?

Measured combustion chamber at 55 today. Using AA's compression calculator, with .080 deck height, compression comes out at 9.1. I'm tempted to use spacers to achieve .080 deck height and 9.1 c/r. Pretty sure I've measured and calculated correctly, but will check again tomorrow.

[emerygt350]

Can't remember... Do your pistons have a valve relief cut in them? That adds a few ccs as well.

[Superhawk996]

Can't remember... Do your pistons have a valve relief cut in them? That adds a few ccs as well.

(IMG:style_emoticons/default/agree.gif) You have to account for your valve pockets too.

[Robroe]

Can't remember... Do your pistons have a valve relief cut in them? That adds a few ccs as well.

(IMG:style_emoticons/default/agree.gif) You have to account for your valve pockets too.

remeasured combustion chamber today with more accurate cc syringe using trans fluid. Including valve pockets in pistons adds up to 58 cc. Based on the AA engine capacity calculator, I'll be right at 9:1 compression ratio.

Crank end play with proper shims is now at .0045". Found a place to have cylinder shims made 10 .150" so I can avoid stacking. Scat VW in So Cal. Should have them in a week or so. Will be traveling the next few weeks but expect to begin final cleaning and case assembly when I return in late Sept.

[Robroe]

Can't remember... Do your pistons have a valve relief cut in them? That adds a few ccs as well.

(IMG:style_emoticons/default/agree.gif) You have to account for your valve pockets too.

remeasured combustion chamber today with more accurate cc syringe using trans fluid. Including valve pockets in pistons adds up to 58 cc. Based on the AA engine capacity calculator, I'll be right at 9:1 compression ratio.

Crank end play with proper shims is now at .0045". Found a place to have cylinder shims made 10 .150" so I can avoid stacking. Scat VW in So Cal. Should have them in a week or so. Will be traveling the next few weeks but expect to begin final cleaning and case assembly when I return in late Sept.

One of you fine gentlemen mentioned that you have a carb you use temporarily for first start cam break in so you can avoid carb set up during cam break in. Is there any chance I could rent your set up for my first start? Would sure be nice to be able to count on the engine running for the 20 mins at 2500 rpm without interruption. This forum is awesome!