Cam Durability Questions
Cam Durability Questions Hopefully I'm beating a dead horse here, that would make answering this that much easier. I'm between 2 cams at the moment: the Texas Speed 228/232 .600"/.600" 112LSA and the Bald Eagle 227/234 .600"/.600" 111+2, leaning toward the Bald Eagle. I see TX Speed sells them in 5150 and 8620 cores. TX Speed said I'd be fine with 5150 and so did Cam Motion. I googled TX Speed cam failures and found jack and **** that could be attributed to the cam itself, so that's encouraging. I'm wanting to put this thing in with PAC 1219 springs (with wahtever pushrods it wants) and be done. It's a fun street car, sees autox every now and again and some day will see the occasional open track day on the road course, but I have a dedicated race car for that. Down the road I envision either porting the stock heads or, more ideally, getting a quality aftermarket casting from Tony Mamo. If/when the heads come off, Johnson short travel lifters are going in but for now I'm hoping to just slide a cam in, tune it, and enjoy it. I've broken out my questions from the rest of this post below:
What material did GM use?
Are there any durability concerns with the 5150 core?
Can anyone speak to the lobe instensity?
Do these TX Speed cams beat up the valvetrain in any other way?
OK to reuse stock lifters?
What material did GM use?
Are there any durability concerns with the 5150 core?
Can anyone speak to the lobe instensity?
Do these TX Speed cams beat up the valvetrain in any other way?
OK to reuse stock lifters?
8620 steel is superior to 5150 for cams. It has to be heat treated correctly, like any alloy steel, but it is a real good steel. It does cost more, generally speaking, than 5150. But imho, I'd prefer it over 5150. Both are good steel...
Teching In
Joined: Mar 2019
Posts: 48
Likes: 3
GM uses 5150 as well as 98% of 'off the shelf' cams, it will outlast your engine most likely and has no known issues. If it's not going to break the bank though I'd probably go 8620, it seems popular in top dollar builds so I'll just trust what people who understand metallurgy etc better than me say lol.
I'd bet there's only a couple HP difference between those cams. Theoretically , the Bald Eagle should make more hp at the top of the rev range. The Bald Eagle is pretty close to the BTR stage 2 I have, just a bit less lift but the lobes are probably different.
8620 is a Nickel/Chromium/Molybdenum alloy steel. Nickel is tough stuff. Molybdenum is a mighty tough, strong metal. The best spindles for I.D. grinding machines have a high concentration of Molybdenum. It is also heavy/dense.
I no sooner posted this than I found a very lightly used bald eagle cam here in the marketplace. Assumption is that it's 5150. The bald eagle will fall off sooner (barely) than the 228/232 as it's a 111+2 vs a 112. I forked out the dough for it so now it seems my questions are a bit moot. I understand the 8620 is harder and, had I bought new, probably would have sprung for that out of paranoia. But since I can't seem to find failure cases on their cams, and 5150 is what they (and Cam Motion) were recommending anyway since it's a fairly mild cam, I should be able to sleep at night.
I no sooner posted this than I found a very lightly used bald eagle cam here in the marketplace. Assumption is that it's 5150. The bald eagle will fall off sooner (barely) than the 228/232 as it's a 111+2 vs a 112. I forked out the dough for it so now it seems my questions are a bit moot. I understand the 8620 is harder and, had I bought new, probably would have sprung for that out of paranoia. But since I can't seem to find failure cases on their cams, and 5150 is what they (and Cam Motion) were recommending anyway since it's a fairly mild cam, I should be able to sleep at night.
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It's all good. Glad you got a deal. As a general rule, most (but not always!) of the time a tighter LSA will carry power out farther w/o a steep drop off, than a wider LSA. Sounds like you found a good cam. I sure as Hell wouldnt fret over it being 5150 instead of 8620. Lifters will never know the difference. The quality, and experience on the job, of the person doing the heat treat is as important as the material itself.
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Verdad Gallardo I was basing my comment on the Bald Eagle cam as having more exhaust duration split which based on what I've read, the wider split should peak higher. But the two cams having different LSA might make it an apple to orange comparison.
Ahh, well not just that but the added exhaust duration in and of itself gives it some legs. It's probably more the advance than the whopping 1 degree difference in LSA that's bringing it all on sooner. I'd also been on the horn with TSP prior to making this post and they confirmed the 228/232 had longer legs, I figured that cam must have been meant to be.
Joined: Apr 2006
Posts: 3,929
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From: Grand Rapids, Michigan
Wrong. A tighter LSA will always carry the power out FARTHER if the cam is set up correctly and the heads have the flow potential, given two cams with otherwise identical specs. Grinder is correct. You are increasing the overlap triangle with a tighter LSA, which will create a greater pressure drop on IVO than a wider one. The problem comes from the fact that for whatever reason, tighter LSA cams get their ICL advanced, and this is what causes the boost in low end and the drop off up top. Earlier IVC will ALWAYS boost low end power. See this test Richard Holdener did, which isn't apples to apples with what I'm talking about, but it shows trends: Obviously, I don't know what ICLs these cams were ground on, but the likelihood is that as the LSA got tighter, the ICL was advanced. This doesn't show the true potential of a large overlap triangle. If the cams had been degreed so the IVC happened at the exact same time, you'd likely see a significant horsepower increase up top. As it is, the tighter LSAs picked up huge down low but either hardly lost any, or gained a bit of power up top. There was an LSA test some years back in Hot Rod with a small block Chevy that made this exact mistake, advancing the ICL for every change ( tighter ) in LSA. This is exactly why, back in 2009, I changed to a 228/232 cam with a 111 LSA, even though I had to flycut my pistons. I degreed the cam to have an IVC only 1 degree later than the 224/228 with a 114 LSA cam I replaced. I picked up everywhere, gaining .2 in the 1/4 and nearly 3MPH. This can't be attributed solely to the increase in duration.
You and wannafbody both have the LSA thing backwards. Tighter LSA comes on sooner, peaks higher, and falls off faster. Wider LSA makes for a lower torque peak, but spreads power out farther on either end of said peak. Ever notice how the stock cams, with no duration, still rev out as high as they do? LSA and cam timing gonna long way to make a tiny cam still have legs. It's not just that it's better for emissions.
Last edited by grinder11; Jan 25, 2023 at 01:27 PM.
Power under the curve definitely goes to the narrow LSA. I'll watch that video after work, pretty sure Richard Holdner and Steve Brul work together seeing how they play on the same dyno. In the meantime, I'll just leave this right here.
https://www.motortrend.com/how-to/ca...ted-explained/
https://www.motortrend.com/how-to/ca...ted-explained/
Power under the curve definitely goes to the narrow LSA. I'll watch that video after work, pretty sure Richard Holdner and Steve Brul work together seeing how they play on the same dyno. In the meantime, I'll just leave this right here.
https://www.motortrend.com/how-to/ca...ted-explained/
https://www.motortrend.com/how-to/ca...ted-explained/
Alright I watched the video last night, that was wild the way that 108 cam got a second wind. I don't think that's how it usually goes, as evidenced by the other dyno pulls in the article I posted and the video. Let's not forget what the valve timing is doing for cylinder pressure, that's why you're getting more under the curve and could explain, in some instances, the absolutely minimal losses up top. I think you picked up your time @LS1Formulation under the curve. And who knows if the second cam just didn't have a better lobe design? My assumption with both articles is that the ICL followed the LSA, so yes the IVC happens sooner with them, but this seems to be the standard. I can see your argument where keeping IVC the same and changing just the overlap would produce a different result.
I just used Summit's calculator and found the IVC for the bald eagle cam is 42.5* ABDC and the 228/232 that I was contemplating has IVC at 46* ABDC. Stock looks to be 39.5* ABDC. I think I chose the right cam for my goals.
TECH Regular
Joined: May 2023
Posts: 427
Likes: 142
From: Franconia, PA
Did you wind up installing this? Ever get it on the dyno?
Earlier this year I grabbed some PAC 1219 springs, a timing chain, gasket set, and pushrod length checker. Then racing season kicked off. I want to grab a wideband before I crack this open and have some cheddar on hand for pushrods. I'm expecting to get into it this winter.
Please do keep us informed. I've pushed my new cam off until next Spring. At that point, I'm getting the cam, pulling the heads for inspection (LS7, need I say more, lol) and installing 8 new Ferrea hollow stem exhaust valves, then installing my new PAC 1905 springs I've had on the bench for 4 months. My current PAC 1905s have almost 50,000 miles on them. But, @TurboBuick6 says with my low .605" lift, they should be fine until then. The cam will be another Futral by Cam Motion. At that point, I'll also go with a new C5R timing chain and gears, and an MSD intake. I will keep you guys informed of what results I get......
I'll post all the gorey details along the way in my not a build thread that's turning into a build thread on CF, but will try to remember to close the loop here with results.