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Old 10-18-2005, 02:03 PM   #31
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One of the limiting factors on our engines is the OEM valve springs, therefore, if you are going to the drag strip, I would recommend a stiffer valve spring for safety reasons. If you get any valve floating with the new camshaft specs, you might damage the engine, even with the RPM range you plan to run. For your application I would suggest an LS-1 spring and also have the cam done by Delta Cams.
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Old 10-18-2005, 03:08 PM   #32
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I've reved up to 6600 rpm with a GT1 cam and 90lb LS6 springs without valvefloat.
With an even milder cam(since your not planning on shifting the powerpand too much) everything over 90lbs will be overkill. You can get the LS6 springs from gmpartsdirect for 70 something shipped and the retainers cost around 30 IIRC.
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Old 10-18-2005, 04:32 PM   #33
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Like 95naSTA suggestted, the LS6 is also a good choice and you can get them at a lower price in Ebay.
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Old 10-18-2005, 07:28 PM   #34
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More interesting news... I spoke with a Delta Camshafts employee over the phone, and he reiterated that the camshaft from the Series 2 3800 does not need rehardening after a regrind. He basically explained that rehardening is a myth that has spawned from people using cams that were improperly reground. In his words, when they do a regrind they never come close to getting through the hardened layer of material.

That'* two vendors so far who have told me the same thing. I'm becoming convinced that I can do a regrind without any trouble. I also ran my idea past him about milling the heads to compensate for a smaller cam base circle, and he said it should work just fine. The good thing about Delta is that they will also provide me with a measurement of the material removed from the cam so I will know exactly how much to compensate in the valvetrain. And they'll do it for about $30 cheaper than CompCams!

Bottom line: this is all great news!
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Old 10-19-2005, 06:44 PM   #35
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SO ship that sucker in lets rock!
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Old 10-19-2005, 07:56 PM   #36
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It'* makes no sense to regring a cam. Quite simply, you will need longer push rods, add this to the cost of the cam regrind and you're NOT ahead of the game.

0.060" is a lot of material to remove from the head. The heads do flex even without being decked when used under high boost condions...I'm not sure how they'll fair in a NA application. Also, you will be reducing the combustion chamber by a fair amount as well...meaning you'll have less mixture to burn.

Cheers,
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Old 10-19-2005, 08:36 PM   #37
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Quote:
Originally Posted by Foghorn
It'* makes no sense to regring a cam. Quite simply, you will need longer push rods, add this to the cost of the cam regrind and you're NOT ahead of the game.
He won't need pushrods, since hes going to mill the heads the same amount that is taken off the base circle of the cam lobe.
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Old 10-19-2005, 11:41 PM   #38
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Quote:
Originally Posted by Foghorn
It'* makes no sense to regring a cam. Quite simply, you will need longer push rods, add this to the cost of the cam regrind and you're NOT ahead of the game.

0.060" is a lot of material to remove from the head. The heads do flex even without being decked when used under high boost condions...I'm not sure how they'll fair in a NA application. Also, you will be reducing the combustion chamber by a fair amount as well...meaning you'll have less mixture to burn.

Cheers,
Thanks for the heads-up Paul. I appreciate an experienced viewpoint on issues like this.

However, Mike is correct in his reply. If you look at the first few responses of this thread, I laid out my plan for L36 budget performance which includes the cam regrind and head work. Depending on how aggressive the cam is done, I may not take .060" off the heads. Chances are it will be less than that, but the determination will come after we find out our options with the regrind. Mike posted a link to a ZZP article where they took an entire tenth off a set of stock heads, so if I'm only doing approximately 50%-60% of that number I should be fine. Heck, I haven't even figured out what my stock piston-to-valve clearances are, so I might be even more limited than I think!

I respect your words of caution, but I think I'd like to try this in order to provide more information on the things that can and cannot be done to an L36. If I screw something up in the name of research, I'll bite the bullet and move on. Whether I succeed or fail, this is going to be a lot of fun!
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Old 10-20-2005, 12:08 AM   #39
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Sorry, I should have read all the posts I see you intend to keep the head milling and reduction in cam base circle the same which would obviate the need for longer pushrods.

I agree that reground cams have been used with a fair degree of success so the process itself is not a problem, especially using roller lifters.

What'* your target compression ratio? Since you're already starting at 9.5:1, head milling can quickly put you over 10:1 meaning high octane fuel is a must.

Since you have a 97, it'* the first year for those that wish to do their own PCM tuning, or you could have someone do it for you to your specs. I mention this because you may want to explore ignition timing advance more than the highest possible compression ratio.

I don't think everyone will agree, but I'm a big fan of timing advance and believe that will get you further ahead than pushing too far on the compression because you can fine tune the timing but you're stuck with the compression.

Edit: One more thought, forgot to mention this before...it'* age I guess

If you mill the heads more than 0.030" you may need to mill the intake manifold to maintain the gasket mating surface geometry. I'm not sure of the specifics for the 3800, but every engine machinist I've chatted with has pointed this out. I think this be especially relevant for these engines as the intake to head gaskets are a rigid extruded type with embossed gasket material...there is next to no give in them.

Cheers,
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Old 10-20-2005, 12:31 AM   #40
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Quote:
Originally Posted by Foghorn
If you mill the heads more than 0.030" you may need to mill the intake manifold to maintain the gasket mating surface geometry. I'm not sure of the specifics for the 3800, but every engine machinist I've chatted with has pointed this out. I think this be especially relevant for these engines as the intake to head gaskets are a rigid extruded type with embossed gasket material...there is next to no give in them.

Cheers,
And thank you for a little more info regarding that as well. Also a previous issue in this thread that was mentioned and will be covered
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