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Missed shift = Upgrade? Need Advice

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Old Apr 29, 2004 | 01:51 AM
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Default Missed shift = Upgrade? Need Advice

Sorry this is little long, but I would really appreciate some advice so that I don't make another stupid mistake. I missed the 3/4 shift and hit second @ ~5500 rpm and obviously over-revved the motor badly. I am still amazed at how easily it slid into gear. I just didn't know until I heard the awful noise.
I had it towed to a local shop. The have pulled the heads and I have bent valves in 6 of 8 cylinders. I've also damaged some of the push rods. 5 or 6 of the rocker arms also look like the needle bearings(?) are loose and seem to be pushing out the side of the rocker arms a little(or at least the cover is), and consequently some of them are a little loose. 6 pistons have been tapped, but they seem to have survived (ie not obvious cracks etc).
For the record, this in on a 1999 WS-6 M6. The car has 30k miles on it, is a daily driver and is stock except for a lid, catback, and a ripper shifter(yes and I still blew it). For at least the next several years, I will have to pass a sniffer emissions test (tests at both idle and during simulated driving).
Here are my questions. I'd appreciate some detailed feedback because I've got to make some decisions tomorrow on what I'm going to do.

1) Do I need to replace all of the rocker arms, or just the ones that appear damaged?

2) If I do need to buy a whole set, I was thinking I should step up to 1.8 or 1.85 ratio rockers. Any recommendation on brand. I don't need the best, just a quality rocker arm for a reasonable price. Should I expect any noticable gain? I don't have any plan to change the cam in the next several years.

3) I can't afford after market heads, but I would consider getting mine ported here locally (Vancouver, Canada). I could get this done for ~US$700 by a reputable local shop. He use a flow bench etc, and comes well recommended. He does apparently get excellent results out of LT-1 heads, but hasn't done many LS-1's. Are there many gains to be had? Is it worth using a guy who hasn't done alot of them before? I would consider doing intake and headers in the future, but couldn't afford it now. The only reason I consider doing this in the wrong order is because I am paying all of the labour costs now anyway. Would a rocker ratio change and head porting get me 40 - 50hp? Appreciate any estimates here. Would this impact my emmisions significantly? or at all?

4) Are stock rods OK, or should I spend the extra to get some Chromoly rods?

5) Should I consider getting the springs changed or are the stock ones good enough for my application? Should I have the stock ones tested?

6) The shop has told me the pistons look OK (eyebrowed, but OK). They didn't seem to think they needed to do anything with them. I have read on other posts that you should file down any high points. Is this to avoid any hot spots that may cause pre-mature detonation? Exactly what should I tell the shop they have to do. I don't want them to miss something here.

Thanks in advance for any advice, I could sure use it. Brian

Last edited by 1999transam; Apr 29, 2004 at 01:56 AM. Reason: spelling
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Old Apr 29, 2004 | 11:40 AM
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ttt. I could really use some advice here. Anyone?
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Old Apr 29, 2004 | 12:09 PM
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Lots-o-questions

Is it at a dealer? Will they even put non-GM parts in it?

If they will... put a cam in it, replace the springs, put stock pushrods in it, and only replace the rockers that are damaged.
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Old Apr 29, 2004 | 12:10 PM
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Originally Posted by 1999transam
Sorry this is little long, but I would really appreciate some advice so that I don't make another stupid mistake. I missed the 3/4 shift and hit second @ ~5500 rpm and obviously over-revved the motor badly. I am still amazed at how easily it slid into gear. I just didn't know until I heard the awful noise.
I had it towed to a local shop. The have pulled the heads and I have bent valves in 6 of 8 cylinders. I've also damaged some of the push rods. 5 or 6 of the rocker arms also look like the needle bearings(?) are loose and seem to be pushing out the side of the rocker arms a little(or at least the cover is), and consequently some of them are a little loose. 6 pistons have been tapped, but they seem to have survived (ie not obvious cracks etc).
For the record, this in on a 1999 WS-6 M6. The car has 30k miles on it, is a daily driver and is stock except for a lid, catback, and a ripper shifter(yes and I still blew it). For at least the next several years, I will have to pass a sniffer emissions test (tests at both idle and during simulated driving).
Here are my questions. I'd appreciate some detailed feedback because I've got to make some decisions tomorrow on what I'm going to do.

1) Do I need to replace all of the rocker arms, or just the ones that appear damaged?

2) If I do need to buy a whole set, I was thinking I should step up to 1.8 or 1.85 ratio rockers. Any recommendation on brand. I don't need the best, just a quality rocker arm for a reasonable price. Should I expect any noticable gain? I don't have any plan to change the cam in the next several years.

3) I can't afford after market heads, but I would consider getting mine ported here locally (Vancouver, Canada). I could get this done for ~US$700 by a reputable local shop. He use a flow bench etc, and comes well recommended. He does apparently get excellent results out of LT-1 heads, but hasn't done many LS-1's. Are there many gains to be had? Is it worth using a guy who hasn't done alot of them before? I would consider doing intake and headers in the future, but couldn't afford it now. The only reason I consider doing this in the wrong order is because I am paying all of the labour costs now anyway. Would a rocker ratio change and head porting get me 40 - 50hp? Appreciate any estimates here. Would this impact my emmisions significantly? or at all?

4) Are stock rods OK, or should I spend the extra to get some Chromoly rods?

5) Should I consider getting the springs changed or are the stock ones good enough for my application? Should I have the stock ones tested?

6) The shop has told me the pistons look OK (eyebrowed, but OK). They didn't seem to think they needed to do anything with them. I have read on other posts that you should file down any high points. Is this to avoid any hot spots that may cause pre-mature detonation? Exactly what should I tell the shop they have to do. I don't want them to miss something here.

Thanks in advance for any advice, I could sure use it. Brian
1) Replace all of them, you may have a few on the way out that you can not visually see. Better to be safe than sorry.

2) If you don't want to change valve springs go with the 1.8. I believe th 1.8 ratio rocker would put your lift around .525 while the 1.85 would put lift around .545 that would be a little much for the stock springs.

3) If you are under a strict budget, clean up the heads, new valves and reinstall. You might need that $700 for something you did not foresee. You might see 25rwhp with ported heads and rocker arms. If you're going to get the heads ported, might as well install a camshaft and get the most out of them.

4) Chromemoly for added peace of mind.

5) A spring change may be beneficial if you do plan on using 1.85 rockers or a high lift camshaft in the near future. Hindsight is 20/20, you might end up kicking yourself in the *** for not doing valvesprings now if you eventually want to install a camshaft.

6) Sorry i can't help you there. I have also read what you are talking about, but i can't give any helpful suggestions.

Good luck.
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