BBC Cam Lobe Paranoia? - Page 2 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #16 (permalink)  
Old 06-25-2013, 01:55 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,763
Wiki Edits: 0

Thanks: 32
Thanked 91 Times in 86 Posts
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".


    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #17 (permalink)  
Old 07-27-2013, 11:32 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,763
Wiki Edits: 0

Thanks: 32
Thanked 91 Times in 86 Posts
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.
Reply With Quote Quick reply to this message
  #18 (permalink)  
Old 07-28-2013, 12:51 AM
thinwhiteduke's Avatar
Living In The Past
 
Last photo:
Join Date: Dec 2011
Location: Downunder
Age: 55
Posts: 428
Wiki Edits: 0

Thanks: 36
Thanked 36 Times in 32 Posts
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
Reply With Quote Quick reply to this message
  #19 (permalink)  
Old 07-28-2013, 08:11 AM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,023
Wiki Edits: 0

Thanks: 0
Thanked 24 Times in 24 Posts
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!
Reply With Quote Quick reply to this message
  #20 (permalink)  
Old 07-28-2013, 11:37 AM
1Gary's Avatar
Registered User
 

Last journal entry: 383 dyno sym
Last photo:
Join Date: Oct 2010
Location: Roch,NY
Age: 67
Posts: 1,539
Wiki Edits: 0

Thanks: 201
Thanked 156 Times in 142 Posts
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!!.
Reply With Quote Quick reply to this message
  #21 (permalink)  
Old 07-28-2013, 12:07 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,763
Wiki Edits: 0

Thanks: 32
Thanked 91 Times in 86 Posts
Quote:
Originally Posted by 1Gary View Post
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.
Reply With Quote Quick reply to this message
  #22 (permalink)  
Old 07-28-2013, 08:15 PM
Member
 
Join Date: Apr 2004
Location: Cassville,MO
Posts: 861
Wiki Edits: 0

Thanks: 29
Thanked 51 Times in 47 Posts
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.
Reply With Quote Quick reply to this message
  #23 (permalink)  
Old 07-28-2013, 08:43 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,763
Wiki Edits: 0

Thanks: 32
Thanked 91 Times in 86 Posts
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
Reply With Quote Quick reply to this message
  #24 (permalink)  
Old 07-28-2013, 08:55 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,763
Wiki Edits: 0

Thanks: 32
Thanked 91 Times in 86 Posts
Quote:
Originally Posted by tresi View Post
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!
Reply With Quote Quick reply to this message
  #25 (permalink)  
Old 07-29-2013, 04:13 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,763
Wiki Edits: 0

Thanks: 32
Thanked 91 Times in 86 Posts
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
Reply With Quote Quick reply to this message
  #26 (permalink)  
Old 07-29-2013, 04:29 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,036
Wiki Edits: 1616

Thanks: 128
Thanked 598 Times in 547 Posts
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
Reply With Quote Quick reply to this message
  #27 (permalink)  
Old 07-29-2013, 10:24 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,763
Wiki Edits: 0

Thanks: 32
Thanked 91 Times in 86 Posts
Quote:
Originally Posted by F-BIRD'88 View Post
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.
As I said, they assembled the engine the first time ... up to and including the valve lash adjustment.

The springs that I have been using are a single spring with a damper, and are highlighted in the chart above (90 / 291 lb seat pressure), and the parts catalog said that they were good to .600 lift.

When I replaced that Clevite cam with the XE284 ... I noted that .578 lift figure was getting close to that .600 figure, but thought I'd still be OK.

Everyone keeps talking about how steep the ramps are on the XE cams, which has me wondering whether these springs are stiff enough to keep those valves on the cam?

The other thing that has me thinking (you mentioned it somewhere, actually) was incorrect lash adjustment.

Hmmm ... this was just one lobe that was damaged ...
I tried to be careful, but I'll be the first to admit that I don't do this kind of work on a daily basis, and that perhaps I have "just enough knowledge to be dangerous".

I have a friend that suggested using a brake cylinder hone to de-burr that lifter bore. Is that crazy? I'm thinking I don't want to take any MORE chances.

Then again ... I suppose the worst case scenario would be another $200 flat-tappet cam and lifter set ... and I DO have the XE274 (one step down from that XE284) sitting on my work bench.
Reply With Quote Quick reply to this message
  #28 (permalink)  
Old 07-29-2013, 10:37 PM
Member
 
Join Date: Apr 2004
Location: Cassville,MO
Posts: 861
Wiki Edits: 0

Thanks: 29
Thanked 51 Times in 47 Posts
The spring should have been tame enough to not to need any any special break in proceedure. But a couple of thing do stand out. In the video the engine was idling around 1000 rpm that's too slow for a new cam. This is a long shot but you have lost 2 cams for some strange reason. I understand cell phone or camera audio is horrid but it sounds like a thrashing machine to me. Were the lifters on the base circle for each and every valve when they were adjusted?
Reply With Quote Quick reply to this message
  #29 (permalink)  
Old 07-29-2013, 11:35 PM
66GMC's Avatar
Get in, sit down, hang on
 

Last journal entry: Cab Removal
Last photo:
Join Date: May 2005
Location: Olds, Alberta Canada
Age: 57
Posts: 2,763
Wiki Edits: 0

Thanks: 32
Thanked 91 Times in 86 Posts
Relatively new cam.

It had been broken in using the 2500-ish varied speed for 45 mins method.

I just like to run it once in a while, and usually keep the RPM down until it warms up ... as it has forged pistons an a loose fit when cold.

The reason I started it up this particular day was to test larger squirters in order to deal with a lean bog. Going from 131's to 135's seemed to do the trick. I also installed a quick-change kit for the secondaries, but left the black spring in. (One thing at a time, right?)

I've been reviewing pics tonight, and I had posted pics of all lobes earlier in this thread. I hadn't removed ALL of the lifters to inspect them only 3 or 4 near the front of the engine ... and they all looked fine. In retrospect, I wish I had looked at the one that I now know is bad.

However ... zooming in on that last pic, the edges of the lifter looked OK, not rough like they do now. So I'm thinking that something has gone wrong in just the last session that this engine had been run.

Yes, I HAD removed all of the rocker arms, re-installed, and re-lashed them all. I had just replaced the intake gasket, and had laid a peice of shop towel down in the lifter valley, in order to catch the old gasket debris fron the die-grinder / blue roloc disc.

So 2 possibilities ... either I screwed up on the lash adjustment, or perhaps dropped some dirt in on that lobe?

I doubt the dirt theory ... as I poured 2 quarts of motor oil through the oil return openings in the heads to make sure everything was well-flooded with oil just before firing it up again.

I dunno.
Going to sleep on this decision to try ONE MORE TIME with a flat-tappet cam or not. Third time's the charm?

One more thing. One of those Harland Sharp Rocker arms (#1 Intake, I think), was rubbing on the valve cover at one of the dimples for the valve cover bolts, to the point that it rubbed a very small hole right through.

Yes the audio was horrible ... accoustics inside the garage, etc ... but yeah, it did seem to have a bit of a rythym when you listen to it.??? Right around the 55 second mark ... That is the side with the bad lobe AND the rubbing rocker.

Last edited by 66GMC; 07-29-2013 at 11:47 PM.
Reply With Quote Quick reply to this message
  #30 (permalink)  
Old 07-29-2013, 11:48 PM
Member
 
Join Date: Apr 2004
Location: Cassville,MO
Posts: 861
Wiki Edits: 0

Thanks: 29
Thanked 51 Times in 47 Posts
There still is the possiblility that you got a hold of 2 bad cams or lifter sets or 1 bad cam and 1 bad lifter set.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
cam lobe down db flyer Engine 18 05-15-2011 01:59 PM
Cam Lobe Centerline, what does it mean? DadTruck Hotrodding Basics 5 01-29-2011 08:30 AM
Wiped out a cam lobe :( 66GMC Engine 25 04-28-2008 06:49 PM
Any cam gurus here? can you tell from a lobe, what it is? F&J Engine 40 03-06-2008 12:25 PM
Cam: Calculate LCA (cam°) from lobe center angles (crank°)? pgtr Engine 2 09-14-2004 08:28 PM


All times are GMT -6. The time now is 12:19 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.