Author Topic: Another one bites the dust. Cam lobe  (Read 3177 times)

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DWKgalaxie

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Another one bites the dust. Cam lobe
« on: November 24, 2022, 12:45:28 AM »
Well, I got my 390 together and down it the car. .060 4.11 bore stock 390 crank and rods, ARP bolts thru out. DSS 5003-4110 10cc dish with 10.08 comp with 72cc heads. ProMaxx shocker 200 heads with 2.20 and 1.73 valves. Performer RPM intake and Performer RPM 800 carb. Now the problem. Edelbrock Performer RPM cam. This is a COMP CAM and lifters. I know I'm not the first, but I just had a cam lobe flatten out or the lifter failed and mushroomed out. Just one lobe that I can tell. The lifters will all slide up out of the bores easily except one. It comes up and stops just as the contact surface comes up to the bore in the block. Like a 400k mile old lifter. I went thru the break in process by the numbers. I have built several Chevy and Mopar motors thru the years and never had a cam break in problem. This is my first FE build, although I've had four before, just never put a cam in one. This really sucks. I guess its time to pull it all the way down with all new bearings, disassemble the roller rocker shafts and inspect them. Maybe even look at the rod bushings. Do you think that I am just one of the many many to be bitten by these COMP CAMS defects they are putting out? Any suggestions for a replacement ROLLER cam and lifters and pushrods with around the same specs as the Performer RPM cam that is 296 Adv int/exh 236 @.050 Duration 572 lift int/exh with 108 LSA 103 int centerline. I understand using the 128 rule that the 108 LSA should be correct for me. This is going in a 64 Galaxie fastback with a TCI streetfighter C6 and a TCI breakaway 2400 converter. I will be running 3.89 gears. I know, a bunch of questions. But any thoughts or ideas would be great. Thanks

blykins

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Re: Another one bites the dust. Cam lobe
« Reply #1 on: November 24, 2022, 06:36:08 AM »
Not trying to be argumentative here, but why do you think it's necessarily Comp Cams' fault?   All of the cores that are used come from about 2 core houses. 

Most of the time, when I see someone smoke a cam, it was because of one of these things:

1.  Didn't check that lifters rotated freely in bores before putting intake on.
2.  Too much spring pressure. 
3.  Not the correct oil. 
4.  Cranked it too long before the engine fired.

I hear, "I never had trouble breaking in cams until recently" quite frequently from some of the "older generation".  It's because they were used to breaking cams in with factory valve spring loads.  Today, if you buy a new set of cylinder heads, the spring loads are WAY over what should be used for a flat tappet camshaft.

FWIW, to this day (knock on my head), I have yet to have camshaft issues.  I don't do a ton of flat tappet builds, but I do use them. 

When I set up the heads, the majority of the time, I will set the seat loads up below 100 lbs seat and the open loads way under 300.  If I have to pull the inner springs out to do that, then I do.  If I have to completely swap to another valve spring, then I'll do that too. 

Gotta have *quality* engine break-in oil, such as Joe Gibbs, Brad Penn, etc.  If you use a regular motor oil, even with some kind of additive, chances are it won't be enough. 

To answer your other question, the first thing I'd do is check the filter.  If there's not much metal in it, then I would drop the pan and check a couple of bearings.  If everything looks good, then I would make a decision on what you want to do with the new cam, then flush the engine a time or two with fresh oil before starting. 

Comp Cams seems to get the blame when cams go flat, but it's because they are the largest camshaft supplier that I know of.  Obviously, when you look at a statistical bell curve, their failures will be higher just from the sheer numbers of cams they put out, but I would venture to say that most of the time, it's the builder's fault.   There are mishaps that can be attributed to the supplier (possibly a bad heat treat, etc.) but generally it's not the cam grinder's fault. 

EDIT:

I don't use ProMaxx heads, but I went to their website and looked for spring loads.  If you bought their heads setup for a hydraulic flat tappet camshaft, they are advertising 145 lbs seat load.  If you didn't pull the inner springs out or change springs for break-in, that's why the cam lobe went flat.  They're showing 145 lbs seat and 350 lbs open at .600".  Too much spring load for a hydraulic flat tappet camshaft, especially for break-in.
« Last Edit: November 24, 2022, 07:20:40 AM by blykins »
Brent Lykins
Lykins Motorsports
Custom FE Street, Drag Race, Road Race, and Pulling Truck Engines
Custom Roller & Flat Tappet Camshafts
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
www.customfordcams.com
502-759-1431
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blykins

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Re: Another one bites the dust. Cam lobe
« Reply #2 on: November 24, 2022, 06:40:29 AM »
I will tell you that most FE combinations will lose horsepower with a single pattern camshaft, so a 236/236° at .050" cam is already not in your favor.
 The ProMaxx heads show about a 70% intake/exhaust flow ratio, so in actuality, you will need something like an 8-10 degree split.  The LSA is based on how much overlap an engine needs.  A 400 inch engine with a modern cylinder head will not want a 108 LSA, *especially* with the advertised durations that come with that camshaft that you have.  I'd be surprised if you didn't need a 111-112-113 LSA to make efficient horsepower. 

Your cam has 80° of overlap, which is about 15-20 degrees more than what you need, depending on what your goals are.   Your DCR is about a half point low as well with that camshaft.   It would sound good and that's about it.  Engine combinations need a specific amount of overlap to function, depending on the applications and goals.  If you don't have enough overlap, then your engine is not efficient.  If you have too much overlap, then you're pushing power out the exhaust pipe and your engine is not efficient. 

There are no magic rules that spit out LSA's.  Vizard himself will tell you that his rule only works on SBC's and I'm skeptical that it even works on Chebbys. 

I don't necessarily think you need to switch to a roller camshaft, because that would require changing pushrods, distributor gears, cam, lifters, etc., etc.  I'll wait to hear what the spring loads are before I give further advice. 
« Last Edit: November 24, 2022, 07:17:46 AM by blykins »
Brent Lykins
Lykins Motorsports
Custom FE Street, Drag Race, Road Race, and Pulling Truck Engines
Custom Roller & Flat Tappet Camshafts
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
www.customfordcams.com
502-759-1431
Instagram:  brentlykinsmotorsports
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machoneman

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Re: Another one bites the dust. Cam lobe
« Reply #3 on: November 24, 2022, 12:08:39 PM »
Think your #1 (Didn't check that lifters rotated freely in bores before putting intake on.) is a major cause. Older engines have varnish buildup on the bores, especially below the area swept by a new higher lift camshaft (lifter now travels further down/up).

Have had instances where one or two bores (older engines) prevented easy lifter rotation. One was easily fixed with more cleaning while oddly the other needed a brake hone (something I used to avoid in all cases!) to allow rotation.

Funny, but it is easy to check all 16 in any V-8 w/o the cam installed. Many don't and suffer a flat lobe. 
Bob Maag

My427stang

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Re: Another one bites the dust. Cam lobe
« Reply #4 on: November 24, 2022, 03:03:47 PM »
Well, I got my 390 together and down it the car. .060 4.11 bore stock 390 crank and rods, ARP bolts thru out. DSS 5003-4110 10cc dish with 10.08 comp with 72cc heads. ProMaxx shocker 200 heads with 2.20 and 1.73 valves. Performer RPM intake and Performer RPM 800 carb. Now the problem. Edelbrock Performer RPM cam. This is a COMP CAM and lifters. I know I'm not the first, but I just had a cam lobe flatten out or the lifter failed and mushroomed out. Just one lobe that I can tell. The lifters will all slide up out of the bores easily except one. It comes up and stops just as the contact surface comes up to the bore in the block. Like a 400k mile old lifter. I went thru the break in process by the numbers. I have built several Chevy and Mopar motors thru the years and never had a cam break in problem. This is my first FE build, although I've had four before, just never put a cam in one. This really sucks. I guess its time to pull it all the way down with all new bearings, disassemble the roller rocker shafts and inspect them. Maybe even look at the rod bushings. Do you think that I am just one of the many many to be bitten by these COMP CAMS defects they are putting out? Any suggestions for a replacement ROLLER cam and lifters and pushrods with around the same specs as the Performer RPM cam that is 296 Adv int/exh 236 @.050 Duration 572 lift int/exh with 108 LSA 103 int centerline. I understand using the 128 rule that the 108 LSA should be correct for me. This is going in a 64 Galaxie fastback with a TCI streetfighter C6 and a TCI breakaway 2400 converter. I will be running 3.89 gears. I know, a bunch of questions. But any thoughts or ideas would be great. Thanks

I am going to jump on this too. 

First, sorry about this, sucks to have to do things a second time

Second, something was wrong in break-in or setup, BUT, I do think a hyd roller is a much better bet.  Not to poke at you in any way, but would love to hear what the pressures were, the lube you used, how you prelubed and any details just to see if we could ID a cause to help others

As far as the cam and LSA.  that 128 rule is sort of goofy and almost always ends up in too much overlap if you use a lobe that matches use,  even Vizard doesn't seem to follow it and has some numerical weighted adjustment he refers to for some engines.  In fact, Vizard seems to indicate that he isn't even supposed to talk about it without publisher rights, real odd stuff, and gimmicky IMHO

That being said, valve size per cid is interesting, but there are so many other characteristics to make an engine match use that LSA alone won't even address.   Buy a custom cam spec'd by someone who does this a lot. I don't peddle parts unless I am building the engine, Brent can set you up, or of you really want an opinion happy to help

Last asking for the "same" as the RPM cam, likely is limited as Brent said.  Although I have built a few single pattern builds, even those with decent numbers, it's generally a trade off for another behavior that is equally important.  I generally see better with more exhaust lobe and proper overlap.  How much of each depends on use and head design.

Hope to hear back on what happened, always good to find a cause

---------------------------------
Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

gdaddy01

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Re: Another one bites the dust. Cam lobe
« Reply #5 on: November 24, 2022, 08:04:42 PM »
did your block have a cam thrust plate on it? if older block the cam was the thrust plate , easy enough to over look.

Rory428

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Re: Another one bites the dust. Cam lobe
« Reply #6 on: November 24, 2022, 11:38:27 PM »
Excuse my ignorance, but what the heck is "the 128 rule" for camshafts? Never heard of such a thing.
1978 Fairmont,FE 427 with 428 crank, 4 speed Jerico best of 9.972@132.54MPH 1.29 60 foot
1985 Mustang HB 331 SB Ford, 4 speed Jerico, best of 10.29@128 MPH 1.40 60 foot.
1974 F350 race car hauler 390 NP435 4 speed
1959 Ford Meteor 2 dr sedan. 428 Cobra Jet, 4 speed Toploader. 12.54@ 108 MPH

Katz427

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Re: Another one bites the dust. Cam lobe
« Reply #7 on: November 25, 2022, 07:25:36 AM »
The "128" rule is a mathmatical correlation,  by David Vizard, for specially SBC engines. He developed it from his years of dyno testing, and development on the SBC. He states, that the "128 rule" only worked on SBC With modern cylinder heads. He also states he DOES NOT  have enough data to confirm that the 128 rule holds for any other engine. You can find David's  explanation of the "128" rule on his site.  The main point of Vizard's work is that the old traditional methods and practices for camshaft design, are not applicable too today's modern cylinder heads, with much improved design.

6667fan

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Re: Another one bites the dust. Cam lobe
« Reply #8 on: November 25, 2022, 06:28:55 PM »
Brent, I think I’m going to print your first response and carry it around in my wallet. That way I’ll be prepared when choosing a flat tappet camshaft comes up with my buddies, ( which it does with some frequency).  My response will be, “ yes, you can run one if you check all these boxes.” One problem out there is not every builder is cool with being asked if all the boxes have been checked. I had to sever ties with one builder cuz asking too many questions made him feel like I was challenging his skill set. ( We’re still friends, he just doesn’t build engines anymore for me).

I feel your response was very informative.
JB


67 Fairlane 500
482 cid 636/619.
Tunnel Wedge, Survival EMC CNC heads, Lykins Custom Hydraulic Roller, Ram adjustable clutch, Jerico 4-spd, Strange third member with Detroit Locker, 35 spline axles, 4.86
10.68@125.71 1.56 60’

e philpott

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Re: Another one bites the dust. Cam lobe
« Reply #9 on: November 26, 2022, 11:09:34 AM »
I take a swag . New Cam and Lifters SUCK and light spring pressure is the answer to the problem . Engine run stand and light spring pressure are the answer , break in , switch out springs and then install into vehicle is what works . We never had to do this in the late 70's and 80's even with stout spring pressure they didn't wipe very often and when they did wipe used lifters were involved so something has changed . You can have everything right except the spring pressure and still wipe , Chevy guys have the 1.3 ratio rocker for break in but what ever the reason we never used to have to do this stuff for a cam to live

blykins

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Re: Another one bites the dust. Cam lobe
« Reply #10 on: November 26, 2022, 12:18:09 PM »
I'm not saying that it's never the cam or lifter manufacturer's fault, but I will tell you, a cylinder head that comes with a 145/350 lb valve spring package for a hydraulic flat tappet camshaft is not configured correctly.   I have ran hydraulic roller camshafts with 150/350 lbs of spring load. 

Guys that don't know any better will assemble the engine and throw a new cam/lifter set in the engine without looking at valve spring loads.  It's a recipe for disaster.  There's not a street hydraulic flat tappet camshaft out there that needs 145 lbs of seat pressure. 

It's just not the 1960's anymore.  Camshafts back then required way less spring load because they were just lazy old cams.  Sixty years of technology improvements have netted camshafts that are more aggressive.   There's just a different set of rules now. 
Brent Lykins
Lykins Motorsports
Custom FE Street, Drag Race, Road Race, and Pulling Truck Engines
Custom Roller & Flat Tappet Camshafts
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
www.customfordcams.com
502-759-1431
Instagram:  brentlykinsmotorsports
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gregaba

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Re: Another one bites the dust. Cam lobe
« Reply #11 on: November 26, 2022, 02:59:41 PM »
Just a question.
I would be interested in a set of low psi springs just for break in. One's that would take 2500 RPM for 20 pr 30 minute's.
Have 2 engines I will be installing in the next year and I would just as soon change the whole set of spring's then having to take out the inner spring and then having to reinstall.
Would need ones that would work on a 429 and a 428. and if they would work on 351 C's that would be a bonus.
Any suggestion's?
Greg
 

e philpott

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Re: Another one bites the dust. Cam lobe
« Reply #12 on: November 26, 2022, 03:08:46 PM »
I agree the OP had too much pressure at 145 but we still had 120 130 seat pressure back in the 80’s and not wiping cams even the big one

blykins

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Re: Another one bites the dust. Cam lobe
« Reply #13 on: November 26, 2022, 03:20:38 PM »
Greg, I certainly wouldn't buy a whole new set of springs for a cam break-in.  You'd have to find a set that worked with the retainers and locators you have, or otherwise you're looking at changing those out too.  Check your spring loads without the inners, that's the easiest way. 

Brent Lykins
Lykins Motorsports
Custom FE Street, Drag Race, Road Race, and Pulling Truck Engines
Custom Roller & Flat Tappet Camshafts
www.lykinsmotorsports.com
brent@lykinsmotorsports.com
www.customfordcams.com
502-759-1431
Instagram:  brentlykinsmotorsports
YouTube:  Lykins Motorsports

gregaba

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Re: Another one bites the dust. Cam lobe
« Reply #14 on: November 26, 2022, 03:27:28 PM »
Thanks Brent
It was just a thought, as I am known to be a little lazy.
I did have a set of 60 year old 390 spring's I was going to use but I guess I lost them when I had the junk dealer hall off 3 trailer load of part's that I needed to move to make room.
Greg