Maximum Allowable Variance in Deck Height, Stock 2.0 Liter Four |
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Maximum Allowable Variance in Deck Height, Stock 2.0 Liter Four |
motorvated |
Jan 18 2020, 10:18 AM
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#1
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Member Group: Members Posts: 280 Joined: 13-February 13 From: Colorado Member No.: 15,519 Region Association: Rocky Mountains |
I'm in the process of re-assembling the top end of my stock 2.0 liter four, and I have measured deck heights as follows:
#1 - 0.036 #2 - 0.029 #3 - 0.037 #4 - 0.035 These measurements are with the cylinder base sealing rings in place and the cylinders torqued down snugly and measured with a dial gauge. To me it seems as if I need to add a shim to the bottom of cylinder #2 approx. 0.050 - 0.080 to increase its deck height to within the range of the others. I have a couple of used 0.080 shims, one of which I could add to cylinder #2 to bring it up to 0.037. I have a couple of questions about this. First, how much variance is permissible between the measurements? If the deck heights are all within 0.002 of one another, is that Ok or do they need to be exactly the same. Second, can I re-use one of my 0.080 shims or should I source a new one. And third, do I place the shim on top of the cylinder sealing ring, beneath it, or doesn't it matter. I was planning on putting it on top of the sealing ring. Thanks in advance for your advice. |
rhodyguy |
Jan 18 2020, 11:25 AM
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#2
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,081 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
Did you have you case 'decked'?
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motorvated |
Jan 18 2020, 01:43 PM
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#3
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Member Group: Members Posts: 280 Joined: 13-February 13 From: Colorado Member No.: 15,519 Region Association: Rocky Mountains |
Did you have you case 'decked'? No. Case has not been decked, as this was supposed to be just a top end inspection and refresh with new rings, gaskets, and seals. Should have measured deck height before taking it apart. There might have been a cylinder base shim under #2 to begin with. Haven't measured cylinder head volumes yet, but they also should be consistent so the deck heights should be consistent also so that the compression ratio is the same for each cylinder. At least that's my understanding. If I were doing a total rebuild, I'd definitely get the case decked. |
stownsen914 |
Jan 20 2020, 08:42 AM
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#4
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Senior Member Group: Members Posts: 913 Joined: 3-October 06 From: Ossining, NY Member No.: 6,985 Region Association: None |
Where are you measuring the deck height? I assume near the perimeter of the piston? If so, there can be variation due to rocking of the piston, so a single measurement point can yield a range of inconsistent values. It's good to measure at opposite sides of the piston and average the readings. One easy way is to put a small strip of solder on each side of the piston crown, torque the head on and measure the crushed solder.
Edit - should have mentioned that it's best to turn the engine over to crush the solder. |
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