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Technical
Deck Height - One Cylinder is different, is this okay? Plus 7.3 compression ratio?
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<blockquote data-quote="cunning plan" data-source="post: 603370" data-attributes="member: 4090"><p>So I have measured deck height and I have values of:</p><p></p><p><strong>Cylinder 1:</strong> Deck Height: 1.86mm - Compression Ratio: 7.7:1</p><p><strong>Cylinder 2:</strong> Deck Height: 1.85mm - Compression Ratio: 7.7:1</p><p><strong>Cylinder 3:</strong> Deck Height: 1.85mm - Compression Ratio: 7.7:1</p><p><strong>Cylinder 4:</strong> Deck Height: 2.01mm - Compression Ratio: 7.6:1</p><p></p><p>So Cylinder 4 seems to be the odd one with 2.01mm and a 7.6:1 compression ratio. </p><p></p><p>Two questions.</p><p></p><p><strong>Firstly</strong>, I want this engine to be a little lazy and not over-stressed as I want to try and make it as reliable as possible. So I was thinking of running below 7.5:1 compression, perhaps 7:2/7:3. </p><p></p><p>Is this too low, should I aim for 7.5 or leave it at 7.7, or is 7.7 too high?</p><p></p><p><strong>Second question, </strong> is the difference in Cylinder 4 a big problem? I presume you would want them all to be as close as possible? I am using an old case with an unknown history to build this engine and a new AA 1641 kit.</p><p></p><p>If it is a problem, is it just a case of adding deck height using shims to the other three cylinders to match cylinder 4 - which seems sensible if I want to lower the compression ratio anyway, I certainly do not want to go higher, so hopefully no machining is involved to cut the case on cylinder 4 to match the other 3? </p><p></p><p>What do you all think?</p><p></p><p> :?: <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite3" alt=":(" title="Frown :(" loading="lazy" data-shortname=":(" /> :roll: :| :| :| </p><p></p><p> :sign0009: </p><p></p><p><strong>Engine Specs:</strong></p><p>All stock 1600 parts except:</p><p>1641 Barrels and pistons</p><p>Twin 40 IDFs</p><p>Electronic Ignition</p></blockquote><p></p>
[QUOTE="cunning plan, post: 603370, member: 4090"] So I have measured deck height and I have values of: [b]Cylinder 1:[/b] Deck Height: 1.86mm - Compression Ratio: 7.7:1 [b]Cylinder 2:[/b] Deck Height: 1.85mm - Compression Ratio: 7.7:1 [b]Cylinder 3:[/b] Deck Height: 1.85mm - Compression Ratio: 7.7:1 [b]Cylinder 4:[/b] Deck Height: 2.01mm - Compression Ratio: 7.6:1 So Cylinder 4 seems to be the odd one with 2.01mm and a 7.6:1 compression ratio. Two questions. [b]Firstly[/b], I want this engine to be a little lazy and not over-stressed as I want to try and make it as reliable as possible. So I was thinking of running below 7.5:1 compression, perhaps 7:2/7:3. Is this too low, should I aim for 7.5 or leave it at 7.7, or is 7.7 too high? [b]Second question, [/b] is the difference in Cylinder 4 a big problem? I presume you would want them all to be as close as possible? I am using an old case with an unknown history to build this engine and a new AA 1641 kit. If it is a problem, is it just a case of adding deck height using shims to the other three cylinders to match cylinder 4 - which seems sensible if I want to lower the compression ratio anyway, I certainly do not want to go higher, so hopefully no machining is involved to cut the case on cylinder 4 to match the other 3? What do you all think? :?: :( :roll: :| :| :| :sign0009: [b]Engine Specs:[/b] All stock 1600 parts except: 1641 Barrels and pistons Twin 40 IDFs Electronic Ignition [/QUOTE]
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Deck Height - One Cylinder is different, is this okay? Plus 7.3 compression ratio?
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