Roller or flat tappet cams? shop won't guarantee flat tappet...

Can you do that without removing the heads? And do you have to set lash again etc.?

 

exactly one of the most common reasons and most overlooked you can measure the taper when you unpack the cam. Another reason is not enough clearance in the lifter bores, then the engine not starting right up and you keep cranking and wiping off the cam break in lube, using the right break in oil and lastly crazy valve spring pressures on break in. i bet that would cure 95% of the problems. yes years ago there were a lot of soft cams.

 

I read an article that says you can do this to remove valve springs without removing the head.

Bring the piston roughly up to TDC of the cylinder you're working on and pull the springs. the valves won't fall in, they only drop about 1/4 of an inch depending on your valve reliefs. then change the springs and move to the next cylinder.

 

High volume builders, not specialized in any particular make, are simply not going to fuss with noisy/rpm limiting lifters. That is the real issue these days, not so much grinding up the lobes type failures.

As a shop owner, your left with an engine that your customer does not like, it doesn't make any difference how good the rest of your work is. So many shops just X out the hyd flat tappet lifter option, to protect themselves. Now with a Buick, if your not doing anything but roller cam motors, they you haven't been doing any Buicks lately.. that stance is easy to take with an LS, because you can pick up the phone and order an LS roller cam from dozens of vendors..

Lifter issues suck, trust me.. been there, done that. But I think throwing the baby out with the bathwater is silly. Built several hyd flat tappet motors here recently, no issues at all, just have to know what your building (Buick 455's in general). While you may have the most talented machinist in history there, the reality is most of these machine shop owners are so busy trying to work with everything, their specialized knowledge on something like our motors is limited, or non existent.

So he is adopting this stance to protect his business.. and I don't blame him, I shutter to think about trying to keep up with all the challenges and changes that happen every year, when you talk about any one engine, let alone trying to stay on top of all of them.

That's where a brand specialist comes in... I don't make small holes bigger, crooked holes straight, or warped surfaces flat, that's not my deal.. customer's come to guys like me, because we have forgotten more about our particular specialty, than most general shop owners will ever know.. and often it's what you don't know that spoils the project.

So that is what is really going on here, it's not about soft cams or break in proceedures, it's about product knowledge and how hard your willing to work at something.

Good luck with it.

JW

 

I don’t know about his builder,but my builder is specific to his builds,products,etc,and even like some of the well-known Chevy builders,the cam/lifter failure rates have broken out like a bad rash. At the end of the day,there are no guaranties,but there are still reputations that these guys take pride in keeping positive. I think we have all seen some differences and issues in the last 4 years. Sure,some of us have seen it before when a certain manufacturer begins having issues,then you find out they changed something in the process,whether it’s supplier,machining,treating,etc.,but recently,there been a lot more of them.

 

Wow, I have been following this from the start. I'am so confused.
If the problem is NOT the product quality but more in the engine building process.

What are these engine builders doing wrong???

Man, I'am old, I have never seen these problems in the 70's and 80's.
What is making the engine building process so much different? Vet

 

it is product quality too with no taper, bad lifters. gm back around 1980 replaced 1000's of cams on their 305 motor and maybe other motors too can't recall.

 

I had a chat with my engine machinist about flat tappets and he said he will no longer guarantee them either and does not know a shop in our area that will. He will still install them for a customer if asked but no guarantee as to the length they will survive. He will guarantee the rest of the work. He is downsizing and typically does not finish assemble any more anyway. He mostly does the machining and lets the customer sort out the assembly.
Greg

 

I can’t speak for other machinists,but for mine,it’s the product,period.

 

OK, now that makes more since.
I think I remember reading about something about GM having cam problems. If I remember correctly, it was poor heat treating that didn't meet
hardness specs.
I just I didn't comprehend Jim's post.
I know there are some minor differences between internal combustion engines (V8's), for the most part they are very similar.
I just couldn't see how the engine building process could be the negative effect since the defects seem to be cam and lifters.
From what I'm hearing, it's mostly the lifters.

That said, I have been watching Powell Machining on YouTube and he has shown that both the cam and lifters are not heat treated to specification,
plus, some cam lobes are not being grind correctly for the angle to spin the lifter.

In sum, what the heck has happened to our manufacturing expertise??????
Everybody has to buy roller cams to feel confident their cam will not fail until the bearing come flying out when it breaks and migrates into the entire engine. NOT FOR ME.

 

A guy I work with runs super stock and builds a lot of super stock engines for others. He says when comp cams was bought out the guys that had a clue were either let go or quit. Now no one there knows anything. They kept sending him custom ground flat tappets with little to no taper. He would call and talk to them about it and they would tell him it would be fine. He knows it’s not but couldn’t talk any sense into them. He now deals with Bullet and they give him exactly what he wants.

 

That's what I'm talking about. This is a perfect example. When you don't have expertise in ANY skilled form of manufacturing, you lose the ability to build parts that meet the required specifications that are called out.

I used to work for a manager who had no clue what it takes to design, machine any particular mechanical device. He used to complain to me it's taking too long to design the part, just go ahead and start the machining process.
I told him, what would you like me to do? take a piece of stock out of the rack, cut it to size (hope that was correct) and start machining it as I go,
and when I screwup because I don't have a blueprint with specifications to go by, throw that in the scrap bend and start all over again?

There is a huge reason why there is an engineering design process to everything that is being manufactured. We as machinist are well trained and have the know-how, to do it correctly.
If you give a machinist a blueprint that does NOT specify the cam lobe angle (spin angle for the lifters), he will grind it exactly the way you specify it.
If he's a friend, he will attempt to correct you.
All mistakes start at the TOP of the food chain feeds itself to the employees. VET

 

An old, simplistic set of rules taught to me during my design/release engineering & manufacturing engineering & program management days. It all begins with the person (you) who wants something done/made:

1. Know what you want (understand the thing and its desired function to the nth degree)
2. Write it down (prints, specifications, testing methods, performance requirements of Step 1)
3. Give it to me (effective communication of Step 2)

In my experience, a lot of folks don't spend nearly enough time on Step 1...the rest is then doomed.

Devon

 

The Johnson 1405J lifters TA recommends are U.S. made. At least that's better than Taiwan. I am having a hard time talking myself out of using the new TA cam and new lifters TA recommends. It will probably add $1000 to my build with roller stuff.

 

Touche Larry. Your simple equation says it all. Vet

 

If he's got EPA information I haven't heard, I suppose the second part "could" be true.

Until it's proven to me, I think he's taking the lazy/no-thinking way out--blaming the oil instead of blaming the crappy parts.

The entire "zinc" oil myth was fabricated by the cam companies to cover their asses when they started selling cheap-junk Communist Chinese cam cores and lifters just after Billy Clinton gave Most Favored Nation trading status to the Enemy. "Oh, no, it's not a problem with our newly-offshored bottom-feeder parts...ITS THE OIL. Yeah. Yeah, the oil. Damn EPA. Zinc zinc zinczinczinc.

Kinda depends on which lifters you're starting with, and whether they NEED to be reground. Also depends on how accurate the regrinding is.

OTOH, the first thing I put into a block aside from cam bearings and various plugs, is the flat-tappet cam and lifters. Spin the cam, see if the lifters spin. I mark the top edge of the lifter, and the lifter bore with a Sharpie. Spin the cam a few revolutions, watch the Sharpie mark as it progresses away from the mark on the lifter bore.

The Genuine GM lifters had a hardened wafer welded to the bottom. Other manufacturers simply hardened the parent metal of the lifter body.

All of 'em were hardened. Sorta like valve seats--some were induction hardened parent metal, some are discrete inserts.

Now, when the Chinese R&D (Receive and Duplicate) decided to knock-off properly-made lifters, they apparently forgot to do proper heat-treat, or bottom radius, (or whatever) and nobody in this country did appropriate incoming inspections 'cause that would cost money and the whole reason to offshore the parts in the first place was to cut costs.

Back to Billy C.

No. But that's what the cam companies wanted you to think.

If it were me, I'd either:

Feed in some rope with the piston coming up on the compression stroke. Leave six inches hanging out the spark plug hole so that you can pull it back out when you're done. When the piston is pushed up, the rope compresses and holds the valves against the seats.

Or

Pump compressed air into the cylinder with the piston at TDC-Compression. Again, pressure holds the valves against the seats. The valves don't drop down at all unless you're exceptionally clumsy; and then they only drop as far as the piston will allow.

Cheap junk knockoff parts, somewhat offset by obsessive engine-building techniques. But made more complex by more-radical cam grinds, stiffer valve springs, and higher expectations for power output.

Yes, GM (and others) had certain problems with cam/lifter failures. Make millions of engines for years on end using various suppliers...things happen. That's why GM and every other carmaker has a warranty period.

Went into hibernation when our political leaders and corporate management criminals decided to care more about our enemy's economy than our own.

It's not about skill or ability, it's about improving profit margins in the short term. Fixing this is going to require some remedial work, and a giant heap of expensive modern machinery, tooling, and buildings to put 'em in.

See reply immediately above. I think we're in complete agreement.




If this were me, and I were forced to use a flat-tappet cam/lifters with stock or mild valve springs, I would want a nitrided cam, and not one with radical opening/closing rates. I'd consider the DLC-coated lifters sold by Comp Cams, but I have no experience with them; and they're "Chevy" lifters which may or may not have a proper oil band, and may or may not need different-length pushrods.

 

Since I dropped the heads off at the shop, I don't recall (or know what to look for) but someone told me today that stock 72 heads do not have inner springs. My eyes are bad. Do these have inner springs?

 

I see an inner flat-steel damper, but not an inner "spring".