35% leakdown in #7
03-12-2015, 05:37 PM
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35% leakdown in #7 LS2 with L92 heads, 222/230 0.597" cam, 11:1 CR.
About 35k miles and maybe 15 track days (road course) since the build.
I figured it was a good time to have the compression checked, here's what they got:
225, 240, 230, 230, 235, 225, 195, 225
Leakdown test of #7: 35%.
Leakdown test of #2: 5%, and another cylinder checked out at 10% if I recall correctly.
Obvi, something's up with #7. Trusted shop owner/mechanic/fellow V8 RX7er says it's in the bottom end and not the valves. So, rings and/or piston are compromised I suppose...
Possible courses of action that occur to me:
1. Do nothing, drive it, take it to the track, monitor compression/leakdown numbers
2. Remove head, extract piston #7, replace with new piston and rings
3. Replace entire bottom end
4. Swap in a rotary (nyuk nyuk nyuk)
I'm thinking option 2, but very interested to hear what the LS engine gurus have to say.
*If* I went with option 1, what are the chances it would result in catostrophic failure vs. just that cylinder running weak?
90% I'm going option 2 but I figure someone here might have words of wisdom for me
Thanks!
About 35k miles and maybe 15 track days (road course) since the build.
I figured it was a good time to have the compression checked, here's what they got:
225, 240, 230, 230, 235, 225, 195, 225
Leakdown test of #7: 35%.
Leakdown test of #2: 5%, and another cylinder checked out at 10% if I recall correctly.
Obvi, something's up with #7. Trusted shop owner/mechanic/fellow V8 RX7er says it's in the bottom end and not the valves. So, rings and/or piston are compromised I suppose...
Possible courses of action that occur to me:
1. Do nothing, drive it, take it to the track, monitor compression/leakdown numbers
2. Remove head, extract piston #7, replace with new piston and rings
3. Replace entire bottom end
4. Swap in a rotary (nyuk nyuk nyuk)
I'm thinking option 2, but very interested to hear what the LS engine gurus have to say.
*If* I went with option 1, what are the chances it would result in catostrophic failure vs. just that cylinder running weak?
90% I'm going option 2 but I figure someone here might have words of wisdom for me
Thanks!
03-14-2015, 09:35 PM
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If its aluminum block it's out of round and needs a proper hone most likely and that is caused by detonation
Iron block you might have a chance of the rings only being bad and nr 2 is possible
Iron block you might have a chance of the rings only being bad and nr 2 is possible
