Wiped a Cam Lobe...What Next?
 

I noticed a valvetrain tapping noise in my professionally rebuilt stroked 427 CO. The engine was broken in and dyno'd by the builder (490HP at 5,400), and I have run it for less than 2 hours total.

I pulled the valve covers and noticed that the #7 Intake valve had over 1/8" of lash. Used a dial indicator on that cylinder and found only .200" of gross valve lift on this valve. Cannot pull this lifter out. Noticed a very small amount of fine metal particles in the oil filter medium and oil pan. I presume the lobe has gone flat.

What do I need to do next (other than the replacement of the cam/lifters) to properly fix this? Has the filter trapped the metal particles or could they have worked their way to the bearings and oil passages? Should I completely tear down the engine, have the block hot-tanked, replace bearings, etc? I do want to do this right, but not incur unnecessary costs. Thanks.

To do it right, you need to tank the block and replace all bearings. Don't forget to pull the oil cooler if you have one and clean it also......

Did you get any kind of warr with the engine? If it $#!T in only two hours run time......something is wrong. This happened to the 406 I bought. The guy had it in a Galaxie ran it for less than 500mi. Cam lobes spanked, pushrods bent. Big mess! He was so pissed he sold me the 406. You probably have all kinds of crap inside the block. Mine did. He might not have followed break in procedures for a solid cam or did not break it in at all. The first 20 min with a solid lifter FE are the most important for break in. Agressive solid cams that require larger dual springs need inside spring removed for cam break in. My 406 had a huge cam with the stock and original valve train. Cam bad, bent pusrods and valves whacked the pistons big mess. It's all being rebuilt to proper specs. Take a further look into it if nothing else is damaged maybe try a new cam and lifters before yanking it out. Do a few oil changes to get some of the crap out and see how it goes. Cut open the oil filters to see how much crap is in them and if it's less each time. Chances are you might have to pull it out anyway so be perpared. What are some of the specs of your engine? Heads, cam, valve train etc... something was not right to begin with and you will want to find out what before doing anything further as far as installing a new cam and lifters go. I'm really sorry to hear of your troubles. I replied to your post on the FF forum also. Good luck, Glenn.

Redd,
Sorry to read of your problem. In your previous post about tight lash I questioned whether you had spec for alloy heads. It's customary to see lash speced at .018-.028 on iron FE's with .006 less for alloy. Your .012 spec suggested aluminum to me with an .018 cold iron spec. [still fairly tight]
I agree with Hotfingers, I'd tear down,inspect all bearings plus crank and cooler if you have one. Look at it this way; 1/8 " is .125." Figure .020-.025 for lash and you've still got .100" of cam lobe [plus lifter face to account for. I think it went all through your system as fine grit. Hope it's not this bad but I'd sure look to find out. See if your builder wants to be cooperative. Good luck and keep your patience.

Red, you are going to have to pull the hole motor, If you can't pull the lifter out chances are the lifter was not turning and thats why the cam lobe failed. Small particules from the lifter and cam get caught up in the windage and coat the piston skirts, chances are you will have to hone those cylinders again if you have room.
There are alot of people running cam lube on the lifter bores during assemble, this causes the lifter to not rotate and will cause cam failure. Did you get a dyno sheet? This should have been found. hope this helps.

Dave

Mine started with removing the intake to have it pressure tested and milled. I reassembled and adjustments kept changing.I also found two lifters that wouldn't come out.I tried to remove the cam through the nose,what a hassel.Held up the lifters with magnets.I stuck a magnet in cam bore and caught each lifter.I got all worried and removed the engine.After a $1,000 Everything had been trapped in filter .Crank was untouched still standard.The changing valve adjustments turned out to be the center two rocker studs on both heads ,heli-coils and all.I had to remove the heads again and have the machine shop machine and install inserts.New comp cam, lifters ,hex adjustable timing set, and pushrods.
I've snice gone off the original sheet of things to do and have the car two feet off the garage floor and it is two years later.Fed Ex and UPS are regulars and still no smoke or noise.

bummer
 

Redd Snake,

I kinda hate to admit it right here for the whole forum to see, but I had the same problem with a CO stroker I built a while back. On the first dyno run it made pitiful power and torque, sounded off kelter, and way too much valve train noise. I tore it down and 2 lobes were wiped out, and those 2 lifters were all mushroomed and would not come out the top. I tanked everything, reassembled with new bearings, double checked those two lifters as I installed them (to make sure they could spin) and went back on the dyno. Same song, second verse.... Tore it down again, same 2 lobes, same 2 lifters. I checked out the bores and they were not located correctly in the block. They were not at the right angle with the cam, causing the lifter and lobe to mate up wrong. I bored and sleeved the 2 lifter bores and it has worked great ever since. This block was a late model "cast as side oiler but drilled center oiler" block and was hydraulic. If yours is the same kind of block, check the lifter bores before you re-assemble. Also be sure you have all the various oil plugs and plungers in place so your oil pressure will be good... The cam relies on oil spray and fog within the motor and has no other direct oil supply. If oil pressure is low, there goes the cam.

Best of luck with the engine!!!

Has anybody ever built an engine with grooved lifter bores?

Groover tool...
http://www.powerhouseproducts.com/st...ry_Code=LIFTER

Ed

Sounds like a good idea - but most of the FE's I build are solid lifter so it would kinda be a waste of time. If you are running hydraulic lifters, it should work fine.

I understand it was a machinist job ,but what did that reboring and resleaving cost? Any guesses how comon this problem might be?How farr off were those bad lifter bores?

Michael,
Quote:

"I've snice gone off the original sheet of things to do and have the car two feet off the garage floor and it is two years later.Fed Ex and UPS are regulars and still no smoke or noise"

Buddy, you have one great sense of humor :p
My coffee just about came out my nose when I read that one.
Don't ever stop posting.
Steve:) :) :)

Mike H,

To answer your question about the lifter sleeves, I did the machine work to sleeve the 2 lifter bores. I don't really do machine work for other people, just for the engines I build - so I may be a little off on a price guess. I can tell you those little sleeves are expensive (about $25 each) and it took me between 3 and 4 hours to get the job done. That should be somewhere around $250 to $300 job.

Hope that helps......

You have me worried .The original owner said he had a cam or two go bad.I don't know if it was the same lobes as my failure.
I've heard about bad breakins and I remember a claim that a lot of cams were prouduced with bad hardening jobs resulting in some soft lobes. mine were one on #1 and one on #7.Tomorrow I'll find the old cam.

After a discussion with my machinist I decided to run it as it stands .Break in seems to be the bigest thing .Perhaps ligthening the valve spring would hepl .But 15 minutes at 3,000 rpm will be a problem.a prolonged carb tuning in back yard was hard .Car need s to be moving.Need a giagantic fan.

Have any of you ever used schubeck lifters? From what I understand, you can even switch cams and reuse the same lifters. The con....... pretty pricey compared to conventional lifters!

Redd,
Slim... but something else to check... A local engine friend had a similar experience with a particular vendors cam that was not ground properly; and it was not just one cam, it was a few of them right in a row from a bad batch. Reportedly, there was a last taper step missing in this particular manufacturers final grind process that prevented the lifters from spinning as required. Maybe you can have somone look at your cam as well to see if other lobes are correct. Good Luck.