Valves hit pistons,update.
02-13-2007, 08:21 AM
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Valves hit pistons,update. For anyone that was following my thread from a couple weeks ago.
https://ls1tech.com/forums/generation-iii-internal-engine/648868-valves-hit-pistons-help-me-figure-out-why.html
I sent the heads out,found out i only had 112 spring pressure due to no shims. We shimmed them for about 135 pounds,replaced 2 bent intake valves,milled the head only about .002 for smoothing purposes. All back together now with new cam. Sound just awesome. Isnt tuned yet so it surges and dies alot. Cant wait to get this thing on the dyno and more importantly to the track. Thanks for everyones help in this matter.
Go ls1tech.
Alex
All new mods in sig.
https://ls1tech.com/forums/generation-iii-internal-engine/648868-valves-hit-pistons-help-me-figure-out-why.html
I sent the heads out,found out i only had 112 spring pressure due to no shims. We shimmed them for about 135 pounds,replaced 2 bent intake valves,milled the head only about .002 for smoothing purposes. All back together now with new cam. Sound just awesome. Isnt tuned yet so it surges and dies alot. Cant wait to get this thing on the dyno and more importantly to the track. Thanks for everyones help in this matter.
Go ls1tech.
Alex
All new mods in sig.
02-13-2007, 08:31 AM
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The machine shop "touched up" the valve job. They said it was totally fine but since they had all the valves out they more of less cleaned it up. I did a leakage test and compression and everything passed perfectly.
02-13-2007, 08:42 AM
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can anyone tell me what is shimming 
is it pushing the springs further down then locking them at a lower point on the stems of the valves .... or to shim is if they`re puting something like a spacer below the springs to compress the springs with the same locking place on the stem without the spacer..... pics of before and after shimming is great if available.
is it pushing the springs further down then locking them at a lower point on the stems of the valves .... or to shim is if they`re puting something like a spacer below the springs to compress the springs with the same locking place on the stem without the spacer..... pics of before and after shimming is great if available.
02-13-2007, 08:47 AM
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Originally Posted by Bader-X
can anyone tell me what is shimming
is it pushing the springs further down then locking them at a lower point on the stems of the valves .... or to shim is if they`re puting something like a spacer below the springs to compress the springs with the same locking place on the stem without the spacer..... pics of before and after shimming is great if available.
is it pushing the springs further down then locking them at a lower point on the stems of the valves .... or to shim is if they`re puting something like a spacer below the springs to compress the springs with the same locking place on the stem without the spacer..... pics of before and after shimming is great if available.
Ben T.
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02-13-2007, 09:03 AM
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In my situation, not having the proper spring pressure did not effect me for about 6k. I was only revving to about 6300-6400rpm and it was fine. As soon as i did my m6 to a4 conversion i reved to about 6700rpm. A few times on the rev limiter due to a 2-3 shift issue is all it took. Lesson learned.
02-13-2007, 09:55 AM
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Im going to take it easy on the dyno. Ramp up the rpms slowly to monitor for any valve floating. My tuner wants to set my shift points closer to 7k. I think im going to do about 6700-6800rpms.
02-13-2007, 01:39 PM
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02-15-2007, 10:30 AM
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Yep learned that leason the hard way. Could have been alot worse. Here is a new sound clip with the new cam in sig.
http://video.google.com/videoplay?do...92109621033441
http://video.google.com/videoplay?do...92109621033441
