We hurt the 496....
11-01-2024 | 10:47 AM
#261
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From: SW Ohio
Guys,
Keep in mind we are still running the stock heads and exhaust. Conventional wisdom says we won't see much over 5300, maybe 5400 RPM. We haven't commissioned the cam yet, but he's telling me this cam will help pull more out of the engine at the RPM the heads and exhaust will allow for. I'm being told by several who have dealt with the builder that valvetrain is his guru zone, and he's used to building WAY more engine than mine.
And, yes.... I am kind of leaning on the fact that I had WAY less spring pressure before (unless they were changed at some point; I will ask), and the engine ran fine. I haven't been given any indication that spring pressure had a hand in the piston failure.
I will be seeing the builder today (he wants money to pay the machine shop and commission the cam), so we will be discussing this.
Thanks. Brad.
Keep in mind we are still running the stock heads and exhaust. Conventional wisdom says we won't see much over 5300, maybe 5400 RPM. We haven't commissioned the cam yet, but he's telling me this cam will help pull more out of the engine at the RPM the heads and exhaust will allow for. I'm being told by several who have dealt with the builder that valvetrain is his guru zone, and he's used to building WAY more engine than mine.
And, yes.... I am kind of leaning on the fact that I had WAY less spring pressure before (unless they were changed at some point; I will ask), and the engine ran fine. I haven't been given any indication that spring pressure had a hand in the piston failure.
I will be seeing the builder today (he wants money to pay the machine shop and commission the cam), so we will be discussing this.
Thanks. Brad.
11-01-2024 | 01:15 PM
#264
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From: SW Ohio
Yeah…. We’re WAY past that point. Besides, we weren’t “stock” before the failure. I ain’t going backwards.
Thanks. Brad.
11-01-2024 | 01:33 PM
#266
Were doomed!
Joined: Oct 2000
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From: Chicago, IL
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-Wally
Money can't buy happiness, but it can buy horsepower. And I've never seen a sad person hauling a$$!
-Wally
Money can't buy happiness, but it can buy horsepower. And I've never seen a sad person hauling a$$!
11-01-2024 | 08:23 PM
#267
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Posts: 6,018
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From: Grand Rapids, MI
These springs aren't making sense. They are 122lbs @ 1.900" installed height, Max lift on the spring 0.640" your cam is 0.627" and the spring needs more than 0.013" shim to achieve 160lbs seat pressure. Your into coil bind at 1.200". Does the builder know the cam specs?
Please someone correct me if I'm wrong.
Please someone correct me if I'm wrong.
Last edited by Rookie; 11-01-2024 at 08:38 PM.
11-01-2024 | 11:19 PM
#268
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Joined: Jan 2007
Posts: 2,070
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From: Murrayville Georgia
My head guy would insist on 200-225 hydraulic, 275 solid. . That bit me in the ass only once with comp lifters that couldn`t take the pressure but Johnsons should be able to handle that with an easy lobe. Otherwise I never had a single valve train issue ever.
My valves got beat up pretty good on the Bad kitty Engines.. I think probably also due to insufficient valve spring pressures or too much lash? I don`t believe the lash was checked after break in.
My valves got beat up pretty good on the Bad kitty Engines.. I think probably also due to insufficient valve spring pressures or too much lash? I don`t believe the lash was checked after break in.
11-02-2024 | 06:50 AM
#270
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From: SW Ohio
These springs aren't making sense. They are 122lbs @ 1.900" installed height, Max lift on the spring 0.640" your cam is 0.627" and the spring needs more than 0.013" shim to achieve 160lbs seat pressure. Your into coil bind at 1.200". Does the builder know the cam specs?
Please someone correct me if I'm wrong.
Please someone correct me if I'm wrong.
Your math makes sense. It is possible that we zeroed in on a spring before deciding to go with a new cam, and then it was out of sight, out of mind. I am running this down with the builder.
Thanks. Brad.
