Technical SBC Bad cam during run-in - Advise needed :)

Processed iron ore is little round balls about the size of a quarter. I know because I have been right in the open pit mines working on the railroad track. and seen processed ore loaded on the railroad cars. When they make new steel they add things like manganese ect to make the desired type of steel. In short the follow a recipe. T1 steel had a different formula than cold roll does. These mills that melt s**** like at Blytheville ark and Newport ark just melt whatever fits into the crucible. much of it is automotive s**** from the car shredder. it contains a lot of impurities stuff like cast iron pot metal, aluminum, chrome plating ,stainless ect. I personally have hauled s**** to those places and watched the s**** being loaded to be smelted. Go on U tube and check out a Guy called Jonathan Winters. He builds his own wreckers and they are super nice. He stated he prefers to use old steel because it is better. The new steel you can be cutting or welding it and have blow outs when you hit impurities in the metal..

 

One can refine s**** iron, even rusty iron. you can make it anything you want by starting with the right ratios and adding the right stuff, burning off the right stuff. You'll need a good furnace operator, a good lab, and a company that cares enough about what they are pouring to get it right.

That **** you mention comes up as slag and it's the furnace operators job to s****e and scoop it off. It's a crazy kind of job to put on a hot suit and stare at 10,20,30,000 lbs of molten metal and scoop the **** load of impurities off of it. Having a cheap company that tries to get more than they can out of a lining and you'll have failed furnace lining materials in the metal too.

 

I just happen to have a chunk of raw iron ore. thought you all might like to see pictures. After it is dug its crushed. run through a grated tumbler with steel balls inside and then washed and it turns into quarter sized marbles. Melted iron ore isn't steel. Its low quality cast iron commonly called pig iron. and your certainly correct adding the right stuff in the correct amounts makes the quality product. However we no longer have the Bethelem countunious casting mill at Gary Ind. Or the US steel mills. We have little s**** melters who are just out to make profit. We don't have a company that cares enough. Its much cheaper to recycle s**** than make new steel. We no longer have Harvey Cranes shop making quality cam cores for almost everyone. Hence the poor quality camshafts.

 

Taconite pellets....

 

Virgin Iron ore pellets have about 70% iron and 30% impurities (junk) . Hard to see how low quality shredder s**** would have a lower iron content and higher concentration of impurities.

 

One thing to keep in mind is that flat-tappet cams are no longer a 'mainstream' part. They disappeared out of nearly all OEM applications about 20 years ago, so the volume of replacements needed has shrunk sharply and some first-tier manufacturers have dropped out of the market (or subcontracted that portion out) due to reduced demand.

We've all seen 'reproduction' parts that aren't up to the same standards as the OEM bits, I suspect that may be part of the issue here...

FWIW, I've replaced lifters-only a few times with no problems, so it can be done. But these were not hi-po motors, with increased lift and spring pressures it can get iffy, particularly with 'generic' lifters.

 

I think the trouble is the amount of extra metals manganese and lime added in the manufacture of new steel can be precisely measured. With recycled s**** its a **** shoot like snowflakes no two magnet loads will be alike. I knew a s**** man who had a contract to sell short steel 3ft X18 in to the steel mill. He would beat on old cast iron sewer pipe engine blocks ect with a headache ball. and load the small pieces into the truck along with the steel. likely every load had 10% cast iron in it.

 

2000 - 3000 rpm's is not harmful to the rings & bearings.

I built many large ***mins & IH diesel engines, both in the engine room of a shop and out in the field (usually inframe, but I did at least once pull an engine out of an old IH TD25C and rebuild it right there in the field, setting it on m***ive 24 x 24 wooden blocks as a makes shift table, using a crane on the back of the truck to lift it as needed to roll it over). Some times rebuilt engines went to a dyno to be run in, but that was the exception to the rule. Typically they were just reinstalled in the machine/truck they came out of. First fire up was to check for leaks, if everything was tight and dry the next step was to bring it up to temp by running it against torque converter stall, and/or hydraulic system stall. Once up to temp it was full throttle and full load to run a series of tests for turbo boost pressure, fuel pressure, high & low idle speeds, and torque convertor stall & full stall rpm's. If everything was within specs, we shut if down, pulled the valve covers and retorqued the heads, reset the valves/injectors, then put everything back together, hoods and all sheet metal and belly pans, and it was immediately put back to work at full load, no babying it at all for any period of time. They might change the oil & filter after 100 hours, but other than that, that machine has to earn it's keep, so it gets no days of easy service. The only engines I ever "broke in" were car and motorcycle engines.

 

Yep, it's been done thousands of times over the decades, and worked just fine. Then again, there have been a lot of failures too. Live a goof life and hold your tongue just right when you start it up and maybe it'll be fine.

 

Thanks for the replies, I just wondered as they sell lifters to replace ones that collapse like mine did and I know people don't replace all and the can. I know I didn't ....just got lucky I suppose

 

After a few wipeouts of the cam lifters, i broke down and spent the money on a roller
The only way to go
Flat tapped during brake in requires break in oil additive and no valve spring pressure (learned the way)
Did a couple that way when the person didn't want to spend the money and it worked but for mine roller is the only way to go


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Roller cams have been around for more than half a century. Detroit diesels used them way back in the 1950's

 

I've always wondered if this might be risky as well, and would like to hear opinions. Obviously it's worked for Old wolf, but wouldn't slight machining variations in blocks cause some issues? If the cam is shallower or deeper into the block the lifters wouldn't be running on the exact same spot of the lobes. The same would be true if the lifter bores were machined in slightly different locations. We're talking thousandths of an inch, nut wouldn't this basically be the same as NOT keeping the lifters matched to the lobe they were broken in on? You'll not convince me that every SBC has identical lifter to lobe relationships.

 

Cam lobes don't really wear, the lifter base wears in to the lobe. The lobe is only hardened to a small depth and during break in the lobe wears the base of the lifter as it spins. New lifters on an old cam that meets spec is the same as new/new. Most cam/lifters are splash lubed thus the 2500 or more RPM for break in. The lifter needs to rotate at break-in or problems will start. Coil bind, zddp, spring pressure all play a part.

 

I've replaced individual lifters lots of time, on regular street cars and they all worked just fine, no failures. The way I see it you have to take great pains to ensure the new installation will not wipe out the cam. I agree that the biggest failure is lifters that do not rotate. The SBC I tore down to build in 2015, I was surprised at how well it ran despite 5 very bad cam lobes. And the amount of **** in the oil pan, super dirty!

 

I swapped in some new Rhodes lifters on a used cam. Used ***embly lube, ran the standard break in process and oil change and it was all good for many years. That was in a Pontiac engine, maybe it's different

 

Small block chevys don't have a plate to hold the cam in place. The timing chain is all that keeps the cam in alighnment. and thus unless you use some sort of cam ****on all small block cams will (walk) and the more flex in the timing chain the more walk you receive. The helical gear on the dist and oil pump drive forces the cam to move foreward at higher rpm. I read that years ago Isky would cut a groove around the centerline of the lobes on the cores and fill that groove with molly before machining.

 

Probably off shore lifters with unknown quality steel in them. Like others, I've changed out one or two lifters on a used cam years ago without any problems, but those lifters were USA made. Unless I found some NOS ones that had been on a shelf somewhere for 20-30 years, I don't think I'd do it now.

Might as well pull it and do a thorough cleaning, and go ahead and hone the cylinders at least and put in new rings and bearings, along with a new cam and lifters, preferably a roller cam. That microscopic metal going through the oil system probably acted like grinding material, chewing on everything it touched. When you're through, you'll know what you have, and not be second guessing it.

 

Chevrolet flat tappet cams are held in place by the angle of the lobe to the lifter base that forces the cam to the rear, forces the lifter to rotate and is stopped only by the thrust surface of the cam gear against the block. The distributor gear has a little to do with it also and the force of the gear pulls the cam to the rear. Cam ****on is only needed on full roller cams.

 

Ive seen holes worn through the front cover from a very loose timing chain.

 

Yeah, I've done that before and got away with it.

It was the new cam and lifters that I had problems with when all the oils changed back in about 2007-2008. That bit me hard!

 

Yes, exactly!!! Plus you won't have the right valve train set up either. Old heads, springs, spring height, collars, keepers, rockers, pushrods and geometry are way off for the cam profiles of today.

Just put the motor together with the parts you are going to run and do it right!

Oh, and as for break in, we built motors and went to the track and raced!

 

An SBC cam kit is like $100.00 I don't understand why you wouldn't just do the cam as well as the lifters. The only way this works out using used lifters on new cam or vise versa is on a Roller lifter application.

 

Pretty much this, if you are stuck on SBC than Jegs has the best deal around it's like $1200.00 for a new longblock.