[Bungee]

Well, after 9 months of waiting, my new 455 was in the Trans Am, and ready for it's first test drive.

The beast roared to life, and shook the ground with the mighty rumpity-rump of a healthy cam and valve train.

The torque was unbeleivable! Despite the tender way I was working the gas pedal and Centerforce clutch, 500+ ft/lbs of torque was making it a chore not to bark the tires at every green light.

But a persistant knock was coming from the engine. A cold sweat washed over me as I considered the worst of two possibilities...either I have a bad lifter, or my cam is slowly being machined to a nice round candlestick shape.

I limp on over to the performance shop that built my motor (BTW, he's the best performance buider in town...but a mostly CHEVY builder, as no one around knows Pontiacs

My first red flag was when he advised me that putting a 455 Pontiac motor in my TA might require modifying the hood, because the motor was too tall ... I quickly realized he was actually talking about a 455 OLDS motor ).

Anyway, the builder is adament that ANOTHER shop (the one who installed the motor, and did the 20-min. break-in), must be at fault. I spend a full day trying to get the straight story from the buidler, the installer, and Comp Cams.

To make a long story short, it turns out the builder didn't "soft-spring" the valve-train for the initial break-in (that is, using single springs)...his "explanation" was that you usually don't soft-spring unless you're building a racing motor.

Yet, Comp Cams' instructions clearly state you have to soft-spring the motor until the cam is broken in. I wonder how many builders don't read the instructions, and blame thier flat cams on poor product?

Just a thought.

[Bungee]

Well, after 9 months of waiting, my new 455 was in the Trans Am, and ready for it's first test drive.

The beast roared to life, and shook the ground with the mighty rumpity-rump of a healthy cam and valve train.

The torque was unbeleivable! Despite the tender way I was working the gas pedal and Centerforce clutch, 500+ ft/lbs of torque was making it a chore not to bark the tires at every green light.

But a persistant knock was coming from the engine. A cold sweat washed over me as I considered the worst of two possibilities...either I have a bad lifter, or my cam is slowly being machined to a nice round candlestick shape.

I limp on over to the performance shop that built my motor (BTW, he's the best performance buider in town...but a mostly CHEVY builder, as no one around knows Pontiacs

My first red flag was when he advised me that putting a 455 Pontiac motor in my TA might require modifying the hood, because the motor was too tall ... I quickly realized he was actually talking about a 455 OLDS motor ).

Anyway, the builder is adament that ANOTHER shop (the one who installed the motor, and did the 20-min. break-in), must be at fault. I spend a full day trying to get the straight story from the buidler, the installer, and Comp Cams.

To make a long story short, it turns out the builder didn't "soft-spring" the valve-train for the initial break-in (that is, using single springs)...his "explanation" was that you usually don't soft-spring unless you're building a racing motor.

Yet, Comp Cams' instructions clearly state you have to soft-spring the motor until the cam is broken in. I wonder how many builders don't read the instructions, and blame thier flat cams on poor product?

Just a thought.

[PonchoV8]

I hope you get taken care of on this. Thankfully, there are several Pontiac builders near me. Top Gun will see mine soon.

Doug

-----------------------------
"...then grease me up woman." Groundskeeper Willie

www.geocities.com/yqtnxnb

[Cliff R]

I haven't had any problems here other than with one of Comp's flat solid grinds. It did not fail, but material was flaking off the high part of the lobes after one season of racing.

I'm not buying the run without the inner spring theory. Sure, the less pressure the better for break-in, no doubt about it. However, we've installed countless cams over the years in street and strip engines without troubles. Some of them had considerable spring pressure. It seems that the start of Comp's troubles coincides with the introduction of their new XE grind camshafts. Perhaps the fast ramps are subseptable to getting cut by the lifters on initial start-up under certain conditions? Maybe the cams are not hardened correctly? I'm not sure, but they are having problems. The machine shop that I use got burned bad recently using an XE grind. 7 lobes went flat in less than 15 minutes!

This ground has been covered before, but there are a few things that the engine builder/installer/tuner can do to help protect the cam from premature failure during break-in.

1. DO NOT use liquid type cam/lifter lubricants, they will not stay in place if the engine sits for any length of time before being started. Use the moly-grease cam lube instead.

2. Static time the engine at about 10 degrees BTC. This is done by aligning the reluctor (electronic) or setting the points to where they are just getting ready to open (points type) while the engine is about 10 deg btc on the compression stroke. Turn the engine and watch the intake valve open, then set the timing next time the marks line up. This will prevent being 180 degrees out.

3. Fill the carb with fuel. Fill thru the vent, don't just pour some in the engine.

4. Pressure test the cooling system and have it topped off. A very small peice of plastic from carb spray tube can be cut and placed in the thermostat so that the system will fill. It will float harmlessly away once the engine heats up.

5. Run the engine at about 1500-1800rpm for at least 15 minutes, do not shut it down unless absolutely necessary. Avoid any periods of idling on the new engine. Have a plan mapped out and sufficient fuel for a nice long test drive. Vary engine speeds/load as much as possible and avoid any high rpms for several hundred miles. At about 100 miles we change the oil and cut open the filter. If it's clean your fine, full of metal.....BAD NEWS!

6. Double and triple check all fuel lines, hose connections and make sure the plugs wires are correct on the cap/plugs.

7. I would avoid the thin 5W and 10W oils. These were designed for modern engines that have roller cams/lifters. We use 15X-40 HD CC/CD oil here, 30WT is also available in HD oil.

Using these guidelines never had the first trouble with premature cam failures....Cliff

[SCOTT ESTERLE]

If you send the cam back to Comp they can check it for lobe taper & hardness. If you don't trust there answer send it to an outside shop to have done.

[tempest455]

I don't buy the valve spring issue either. I've fired motors with lots of valve spring pressure and flat tappet cams, never had a problem. I've also had motors not start or shut off early because of fuel problems, timing problems, trans lines leaking, over heating etc. but never wiped out a cam because of an incorrect break in procedure.

Sounds like a fly by night shop. What did they set the lash at? How much guide/retainer clearance? Coil bind clearance?

Tempest455
http://www.wauknet.com/douthitt/

[Tom Vaught]

In 35 years of installing cams in engines have never had a lobe go flat on initial break-in. I
have used the same methods Cliff R. recommends on
the cam lube etc. I have never had to use the soft
spring approach on any cam other than Super Street
(1000# open pressure) cams and this was probably an extra safety step on my part that was not
needed but I did it for peace of mind.

I have never used the small plastic spray tube deal wedged into the thermostat but now I will!
Learn something new every day. I normally drill
two small (.090) holes in the flat portion of the t-stat to let the air bleed out but Cliff's idea will be faster.

My suggestion would be to talk to the comp Cams people and have them tell you what went wrong. At
the minimum it will give them more data if they do
have a problem and they may even replace the cam.

In the old days you had to buy a complete kit and follow their installation instructions to keep
the cam warranty valid. Good Luck! Tom V.

[Bungee]

In the back of my mind, I have this nagging suspicion that part of the problem was the newly built motor sat at the installer for 4 months before they started it for break-in.

I asked the installer if, in the 4 months before break-in, the cam lube might drip off the cam. He assured me that beacause of the chemical composition of the lube, that wouldn't happen.

[Tom Vaught]

I have a fresh 455 that I built for a guy setting in my garage. I now own this engine. I put cam lube (from the camshaft manufacturer) on the lobes before I sealed it up.

I plan on removing the intake to trial fit the
1966 Aluminum Tri-Power intake on this engine and will take the additional step of removing the valley pan and look at the cam lube on this engine. If it looks good than then reason was not cam lube dripping off after 4 months.

Tom Vaught

[RPM]

Breaking in the cam running on just the outer spings is a precaution you can take but IMHO, with 995 springs or similar, a waste of time. The shop that I use for machine work (and parts) never breaks in a cam with the outers only if they are low pressure like the 995s! They have built many many engines in the last 35 years and their failure rate (from what they told me) is very low like they lost a couple out of a thousand. IF you were to run very high spring pressures, way more than 995s then it would be advisable (again, as I was told). I have broken in a lot of cams over the last 30 years and only recently experienced failure. The last cam was a Crower that is fine but the two prior to that were a Comp XE and a UltraDyne that failed. The Ultradyne seemed to break in fine (it was a solid and the lash did not open up) but by after 60 miles of use the lash opened up .006" on 14 valves. Inspection of the cam revealed porous, rough looking lobes and I had a small amount of iron filings in the filter. It was sent back to Harold and he is taking care of it. I don't know why it was starting to "go".

[Never Enough Power]

It sounds like a bad cam not an improper install by the builder. We have built many motors and never had to perform a break in on springs like Comp says. Sounds like the Co is trying to cover their butt. As far as keeping the thermostat open by using the small piece of plastic tube, I have to disagree. We had a motor, came in with a slight sputter in exhaust.Turned out to be a burned valve due to a small piece of RTV getting into the small coolant hole at the head /Head gasket. If you are going to block open the thermostat, I recommend using a per drilled T-stat, run up to proper temp and then change to a new T- stat. It is not worth the chance of a blockage problem. It may not ever happen but how many motors have a problem because of a 1/8 piece of RTV.

[Taff]

You can also cut a very fine oil channel in the lifter bores to direct more oil to the lifterbase/cam lobe to help prevent cam lobe wear. Comp Cams sells a tool that does this but I made my own out of an old lifter.I've not had any problems with the Crane solid flat tappet I used. I believe Crower sell a lifter with a tiny oil feed hole in the lifter base that does the same thing.

[JEFF KING]

Like the rest of you guys, i,ve broken in alot of cams. Most where Comp cams never had any trouble,
used their K-kit and the springs that came with it.
Worked fine! they could have bad cam i,m sure.
but i think it,s the shop that built it for you.who lashed it? did they? we all know stock pontiac motors new, they just tightened the rockers to 20 ft.pounds. Did this guy see this in a book?(knows chevys) Ok now the motor is changed the heads are taken down, the block is decked things have changed!i,ve seen people do this and the valves where so tight she wouldn,t even start! They were lucky if they didn,t kill a lifter or two after i lashed it out and broke it in for them. Add the fact the engine sat before start-up for a long time and was dry. I would talk to the shop and try to find out just what they did, and take it from there.

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"GTO? Good Times Only!!!" "Get Tools Out!!!"
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[sleepy]

CLIFF 1500-1800rpm for 15 minutes? I've always gone 30 minutes at 2500rpm after setting the timing with the light. start it, set the timing, run it up to 2500 for 30 minutes shut it off, change the oil,check the valve lash,retorque the head bolts[if they were off]. I have NEVER had a cam go flat on me using this method. BTW I always use LUCAS for assembly lube.

[Half-Inch Stud]

Banging of Drum in background:
I've never had a cam wipe, in all my 20years of actual engine camming...

Until last Fall, the Lunati HYD lost 3 lobes soon after break-in. That waws to replace the 12-year old Lunati, that lost 2 lobes last Summer.
-------------------------------------------------
Suuure, I'm wondering.
-------------------------------------------------
Gots me a Used Crower cam and Rhoads lifters. And hope it settles-in my motor, since it is already broke-in.

Half-Inch Stud

"tbdET/1xxMPH/1.xx 60foot/28"/3.54:1/10"/469 #48/Flat HYD/DualQ-Jets/Offyl/3xx0Lbs
11.00/123MPH/1.50 60foot/29.5"/4.10:1/10"/469 #48/FlatHYD/DualQuad/Wenzler/3250Lbs
12.00/112MPH/1.61 60foot/26"/3.31:1/10"/469 #48/FlatHYD/Q-Jet/Torker/3650Lbs
12.70/103MPH/1.71 60foot/28"/4.10:1/12"/469 #48/FlatHYD/Q-Jet/Torker/3950Lbs"

[Kybird]

I never heard anyone mention prelube. A few minutes with a drill after 4 months wouldn't hurt.

[RPM]

Didn't want to post ALL the gory details but I always oil-prime my fresh engines.

[P455]

If Cliff's small plastic tube method makes you nervous about foreign matter inside your engine, do like I do and wedge an aspirin tablet into the thermostat. It'll dissolve away, and your car won't get headaches.

[insert witty signature here]

[JEFF KING]

"Prelube" good point! the shop should of done it Knowing that it sat for a while...Right?
all my motors i,ve done i couldn,t wait to break them in! And make sure i got it right! You always sleep better knowing your engine not a time bomb!

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"GTO? Good Times Only!!!" "Get Tools Out!!!"
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[Tom Vaught]

Like the aspirin idea too. Reason why is a faster complete fill of the cooling system. I realize the spray tube will remove most of the air quickly but the hard aspirin will open a big opening in the stat and even if it desolves before
you fire the engine you will have completely filled the cooling system. Tom V.