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  #16 (permalink)  
Old 06-19-2013, 01:59 PM
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Quote:
Originally Posted by 1Gary View Post
Check the lifter bore clearances.
Well, I'm sure this is not exactly the scientific and/or approved method for doing this, but I lubed up each bore with engine oil, dropped in the lifter, and watched as they slowly sank down to the cam. I picked them up and rotated them in the bore, and found no resistance or lateral play.

Like I said earlier, I'll inspect them for "abnormal-looking" wear ... and ensure that they get returned to their respctive bores. (I know that you don't want to mix them up)

The bores DO look like they were honed when the engine was rebuilt and assmbled by the machine shop in 2005.

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Old 06-25-2013, 12:55 PM
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I had my ex-boss come over to have a look, and his opinion is that the cam lobes look OK.

As to the coolant/corrosion issue, his opinion was (as I had suspected) that it was due to left-over caustic soda from being hot-tanked. He said that a simple flush with fresh water should clear it up.

I had also performed a grade-school science expriment using vinegar and baking soda to test seperate samples of that "technicolor goo", and found no reaction with either. I repeated the tests with samples of the old antifreeze, and again saw no reaction.

I have now completely drained, rinsed, drained again, and refilled with 50/50 mixed antifreeze (about 2-1/2 jugs)

The engine oil and filter have been replaced with 10W30 NAPA (Valvoline) prior to startup. I dropped the dizzy back in, let the elecric fuel pump fill the float boals, pumped the accelerator a few times to get the fuel right there ... and she fired right up!

Next on the agenda is to fiddle with the pump and squirters to get rid of the lean stumble (especially before the engine is right up to operating temp)
And then ... getting that dist advance curve "just right".

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Old 07-27-2013, 10:32 PM
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Another cam BITES THE DUST!

I freaking knew it ...

This is camshaft failure #2 for this engine, and it hasn't turned a wheel yet. ZERO miles ... MAYBE 10 hours of total run time!

The first cam was a Clevite cam, this one is a Comp ... both flat tappet.

NOT the same lobe ...
last time it was #7 Exhaust, This time #7 Intake (2 lobes apart on camshaft)

Yes, as the original thread title implies ... I was worried looking in through the holes in the valley.

I had someone whose opinion I value have a quick look at it, and he thought everything looked good, so I proceeded with the replacement of the intake gaskets (leaking at china wall)

I was super suspicious when I tried to tune this thing ... vacuum guage was not steady ... and ran like a can of rocks.

Bought a different set of used closed-chambered heads AND another new (slightly milder version) camshaft. I HAD the XE284 already sold to another friend building a hot BBC.

So... tonight I made up a set of tags, and carefully labelled and tagged each lifter with the idea of him re-installing each lifter to it's matching lobe.

1,3,5 went along smoothly ... but when I got to the very last lifter on the driver's side (#7 Intake) ... the lifter could not be lifted up any further than the very bottom of the lifter bore, and my heart sunk. Standing on my head and peering in the valley window ... I could see and feel that the edge of the lifter was rough. I wiggled and jiggled, but no way ... it wasn't coming out without a fight.

Now I'm upset ... and yanked that lifter out with a set of needle-nosed vise-grips. Sure enough ... it's FUBAR'D! (and now, more than likely ... so is the lifter bore.)

I'm yanking that short-block tomorrow, and taking the entire engine back to the machine shop. I'm DONE with the DIY engine thing and DONE with flat-tappet cams!

I dunno ... it looks like this lifter wasn't spinning freely in the bore?

BUT ... I could understand that if it was the same lifter/lobe that failed last time ... but why this lobe this time? Yes, cam break-in was done to the letter of Comps instructions this time ... I don't think it would have been possible to be more careful.



More pics in my gallery. I'm going to mix a stiff one before bed.
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Old 07-27-2013, 11:51 PM
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Sorry to hear that your having so much trouble with this, you must be tearing your hair out !
I was like a neurotic wreck when I did mine, followed everything to the "T" also. I used that runny red cam lube from comp, (which scared me cause its so runny) and it got turned over many , many times by hand and sat for prolly eight or ten weeks before it finally got fired up.
I over filled the oil pan slightly , added extra ZDDP removed the inner springs and broke it in for 45 min between 2000 and 3/3200 rpm
Done 2000 miles ATM so far so good...
Mine is a sbc 355 with a comp cams 294S magnum cam.
A lot of guys here don't like the fast ramp cams like the XE series with a flat tappet as it puts a lot of stress on the lifter/lobe interface.
The magnum's slow ramps are more forgiving with flat tappet cams.

FWIW



Duke
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Old 07-28-2013, 07:11 AM
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I had the same problem years ago with a 454. The engine flatten 3 cams during break-in then I went to a roller setup which also didn't run correctly (made too much noise).

Turns out my lifter bores were too tight. The bores had between 0.0005 and 0.001 clearance. You need 0.001 to 0.0015 for a flat tappet and 0.0015 to 0.002 for a roller.

I went back to a flat tappet and added more lifter to lifter bore clearance and it has being running great for 5 or 6 years now.

I added more clearance by spinning new lifters on my lathe and sanding them down -0.001" with 180 grit. I didn't feel like taking the block out again so I did it this way.

Since your cam went flat, you should take the engine apart and clean it. Then you can open up the lifter bores (if that is the problem).

To measure my bores, I machined 5 lifter blanks from 0.000 to -0.002 inches in 0.0005" increments and used them as G0- No Go gages.

I also installed a BC Engineering over-cam oiling system for $50.00.

Other options are to get a machine shop to realign the lifter bores and add bushings. Or you could also go custom and machine the block to use larger diameter dodge or ford lifters but that would require a custom cam grind.

If I use another BBC again (which I doubt), I will use a later model 8 liter with factory roller cam.

Good luck!
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  #21 (permalink)  
Old 07-28-2013, 10:37 AM
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Quote:
Originally Posted by 454C10 View Post
I had the same problem years ago with a 454. The engine flatten 3 cams during break-in then I went to a roller setup which also didn't run correctly (made too much noise).

Turns out my lifter bores were too tight. The bores had between 0.0005 and 0.001 clearance. You need 0.001 to 0.0015 for a flat tappet and 0.0015 to 0.002 for a roller.

I went back to a flat tappet and added more lifter to lifter bore clearance and it has being running great for 5 or 6 years now.

I added more clearance by spinning new lifters on my lathe and sanding them down -0.001" with 180 grit. I didn't feel like taking the block out again so I did it this way.

Since your cam went flat, you should take the engine apart and clean it. Then you can open up the lifter bores (if that is the problem).

To measure my bores, I machined 5 lifter blanks from 0.000 to -0.002 inches in 0.0005" increments and used them as G0- No Go gages.

I also installed a BC Engineering over-cam oiling system for $50.00.

Other options are to get a machine shop to realign the lifter bores and add bushings. Or you could also go custom and machine the block to use larger diameter dodge or ford lifters but that would require a custom cam grind.

If I use another BBC again (which I doubt), I will use a later model 8 liter with factory roller cam.

Good luck!
This sounds familiar doesn't it??.BRAND NEW AFTERMARKET BBC a 565 was breaking valve train parts.........WHY??.Lifter bore was sized wrong.And on a solid roller cam no less!!!!. Finally we got sick of the machine shop(S) B.S. and fixed it ourselfs.Remember me the one with 5 BBC's in a super gas car in four weeks yrs ago??. All valve train related. All roller cams.

Here is the suggestion of the day for all threads...........................READ EACH POST VERY CAREFULLY AND TAKE THE TIME TO CONSIDER EACH ONE!!.
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Old 07-28-2013, 11:07 AM
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Here is the suggestion of the day for all threads...........................READ EACH POST VERY CAREFULLY AND TAKE THE TIME TO CONSIDER EACH ONE!!.
I do try to, Gary.

And yep ... you get a lot of different answers and suggestions from a whole lot of folks ... not to say that multiple views and opinions are not valuable. In fact, I think that is one of the greatest strengths of sites like this one, as they make you think.

I guess I'm no different than most folks ... most of us are hoping for the best, and are occasionally guilty of hearing only what we want to hear.

This all being said, though, there are times when you can do a better job doing it yourself ... and other times when you're in over your head ... and it's best to load it up and take it to a pro.

It's that time for me. I want him to tell me what caused the failure(s), and to correct that problem in the hopes that it doesn't reoccur.

I don't plan to go in there with guns blazing, and making accusations that they must have done something wrong ... let's just fix it, and move on.

My frustration lies in the fact that I'm expending a lot of time and money in "do-overs", and not able to move to the next step in the project.
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Old 07-28-2013, 04:50 PM
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Just looked at your pictures. The last cam I pulled out of a BBC was a isky 292H Mega cam that had well over 20 years of use on it. It and all the hyd lifters were in pristene condition.
This Cam and lifters got retired (upgrade to a solid roller), but could have easily gone right back in this BBC and run for another 20 years.

This is my experience with Isky flat tappet cams. I see the same thing on SBC's using Isky flat tappet cams.
And this is why I use them and recomend them.
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Old 07-28-2013, 07:15 PM
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What's the on the seat valve spring load? Coil bind checked by math and measurement or with a solid lifter installed? You're having more than your share of bad luck with cams. In the future if you have a lifter that doesn't want to come out raise the lifter as high as it will go easily, remove the cam, now drive the lifter down. You can either stick a shop magnet in the cam bore and fish it out or take it out the bottom of the block. The bottom end has been contaminated with metal anyway so you should be pulling the pan.
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Old 07-28-2013, 07:43 PM
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Quote:
Originally Posted by F-BIRD'88 View Post

And this is why I use them and recomend them.
I just glanced at their selection, and noted that they seem to class their cams quite a bit differently than say Comps.

396286 is listed as 224° @ .050, .51 lift which (other than the 108° Lobe Center) would usually be considered pretty "tame" ... yet they are describing it as "lopey idle" and 2500 to 6500 RPM.

My first cam was 224/224 on a 114°, and it would idle quite smoothly at 600 RPM.

Is it the LSA that makes that much difference?
At this point, (if I was interested in a FT cam) ... I'd be more inclined to go with the #396271
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Old 07-28-2013, 07:55 PM
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What's the on the seat valve spring load? Coil bind checked by math and measurement or with a solid lifter installed? You're having more than your share of bad luck with cams. In the future if you have a lifter that doesn't want to come out raise the lifter as high as it will go easily, remove the cam, now drive the lifter down. You can either stick a shop magnet in the cam bore and fish it out or take it out the bottom of the block. The bottom end has been contaminated with metal anyway so you should be pulling the pan.
Here are the valve spring specs, and the parts catalog says they are good to .600 lift. I had the engine assembled by the machine shop the first time. They asked for the spring specs, so I trusted them to ensure that the supplied parts would be OK.



Your lifter removal method makes perfect sense.
I wish I had thought of that!
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Old 07-28-2013, 10:45 PM
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Originally Posted by 66GMC View Post
I just glanced at their selection, and noted that they seem to class their cams quite a bit differently than say Comps.

396286 is listed as 224° @ .050, .51 lift which (other than the 108° Lobe Center) would usually be considered pretty "tame" ... yet they are describing it as "lopey idle" and 2500 to 6500 RPM.

My first cam was 224/224 on a 114°, and it would idle quite smoothly at 600 RPM.

Is it the LSA that makes that much difference?
At this point, (if I was interested in a FT cam) ... I'd be more inclined to go with the #396271
With the same .050" duration, when the LSA is closed up to 108 from say 114 yes the idle becomes more agressive, as the overlap is increased.
It is still a 224deg cam.
Remember this is just the cam catalog. You can have this cam or any cam in any configuration, LSA, dual pattern etc you want.
Some already exist as standard Isky production part numbers.
All can be custom ground for you . If you need help with proper cam selection for your engine all you got to do is call them.
If you want to step up to a roller, they can get you set up for that too.

If you download the online cam lobe spec sheets, you can see a lot of what is available. You can design your own cam and they can custom grind it for you.
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Old 07-29-2013, 03:13 PM
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Should i have the block decked?

OK, the short block is hanging on a chain right now, and I'm hoping to take it to a machine shop tomorrow.

I got to thinking about quench ... but I'm not sure if it's an issue at all, running forged flat-tops in 101cc heads.

By my figuring, using a couple of different compression calculators ... I end up right around 9.0:1 CR.

So let's talk quench. The way I understand and recall it, perfect quench is to have .038-.040" clearance in the area on the side of the cylinder opposite the spark plug. Correct?

The Felpro gaskets that I am using are supposed to have a compressed thickness of .039.

Sooooo ... zero-decking the block with those flat-tops should get me right where I want to be, correct? It will also bring my compression up to 9.3:1
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Old 07-29-2013, 03:27 PM
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They asked for the spring specs, so I trusted them to ensure that the supplied parts would be OK.

you are assuming a lot and taking a lot on faith. If you are the guy turning the wrenches its up to you to check this stuff.
On a BBC when using anything more agreeive than the good old Factory BBC 454-450hp LS6 springs
it is nice to reduce the running spring pressure for the cam break in run.
Remove the inner spring coil on dual springs. Reinstall after it is all broke in.

I allow a full week of moderate street driving when beaking in a new enigine.
Do not allow the engine to idle slow for the first week. Turn the idle speed up 1000-1200 rpm.
Then when everything is friendly, reinstall the inner spring coil and set to height spec as required .
On a hyd cam you should not need more than 320PSI actual open spring pressure at max real valve lift.
The key is enough, but not excessive open spring pressure.
Yup the lifter bores need to be to size spec and no nicks or edge burrs that will prevent lifter rotation.
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Old 07-29-2013, 03:29 PM
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Quote:
Originally Posted by 66GMC View Post
OK, the short block is hanging on a chain right now, and I'm hoping to take it to a machine shop tomorrow.

I got to thinking about quench ... but I'm not sure if it's an issue at all, running forged flat-tops in 101cc heads.

By my figuring, using a couple of different compression calculators ... I end up right around 9.0:1 CR.

So let's talk quench. The way I understand and recall it, perfect quench is to have .038-.040" clearance in the area on the side of the cylinder opposite the spark plug. Correct?

The Felpro gaskets that I am using are supposed to have a compressed thickness of .039.

Sooooo ... zero-decking the block with those flat-tops should get me right where I want to be, correct? It will also bring my compression up to 9.3:1
0.039" quench would be great. There are other ways to get there, obviously. Like using a thinner HG and cutting less off the decks.
Quench
Milling decks

Calculators:
• Many DCR, SCR, and head flow, etc. calculators: here
• Cubic inch: here
• Other various calculators from Wallace Racing
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