454 Flat Cam Question?

[savatreatabvr]

When I adjusted the valves on my mid 70's 454 the other day I thought I noticed cylinder #6 rocker arm not keeping up with the rest. I attached a video of the 454 running with the valve cover off to see if anyone else notices the same thing. Sorry for the crappy video, I used my cell phone, lol!

[Ziegelsteinfaust]

Video not working for me.

Sounds like it is a distinct possibility with today's oils. If this happens to my 350 I am swapping in a 350 Vortec.

Is the adjusting but further down then the others?

[savatreatabvr]

Originally Posted by Ziegelsteinfaust

Video not working for me.

Sounds like it is a distinct possibility with today's oils. If this happens to my 350 I am swapping in a 350 Vortec.

Is the adjusting but further down then the others?

Seems like several are down farther, a few even feel like they're bottoming out when I tighten them. Of course I don't leave it that way but all rocker arms are not the same adjustment.

[geezer#99]

How did you adjust them?
Running or shut down?

[tucsonjwt]

I don't know if this is pertinent to your question, but early 454s were notorious for flat spots on the cams (i.e. "soft" cams.) My 73 454 got to the point where some pushrods snapped and that was cause for a new camshaft and some pushrods, etc. I don't see any particular anomalies in your video, especially for an old truck. I would just wait until your cam gives out and replace whatever breaks - unless your are driving 90 mph on the 101 everyday.

Just curious, why are you doing a valve adjustment?

[savatreatabvr]

Originally Posted by tucsonjwt

I don't know if this is pertinent to your question, but early 454s were notorious for flat spots on the cams (i.e. "soft" cams.) My 73 454 got to the point where some pushrods snapped and that was cause for a new camshaft and some pushrods, etc. I don't see any particular anomalies in your video, especially for an old truck. I would just wait until your cam gives out and replace whatever breaks - unless your are driving 90 mph on the 101 everyday.

Just curious, why are you doing a valve adjustment?

Good point! A matter of fact when I replaced the timing chain I found a 1" piece of push rod in the oil pan. The previous owner must have had problems and replaced a broken the push rod. I have no idea why it broke. Reason for adjusting the valves is it's been running under par and I needed to replace the valve cover gasket anyways so I wanted to kill 2 birds with one ratchet, lol! It's not my daily driver but it will definitely do 90 mph but I rarely do it, I may put 10 or 20 miles on it a week if that. I'm still wondering what made the push rod break in the first place?

[savatreatabvr]

Originally Posted by geezer#99

How did you adjust them?
Running or shut down?

Running adjustment. It's the only way on an engine with high miles.

[GRADYS Performance]

Valves should NEVER be adjusted running.

What do you have for a cam and valve springs?

What are you using for oil?

[bnoon]

Hydraulic lifters should never need a hot or running adjustment. If they come out of adjustment, then either the rocker nut need fixed or replaced, or you have a bad lifter that needs replaced, or a bent pushrod that needs replaced, or the cam lobes are wearing out. Once the surface is worn more than a few mils, your cam lobes will wear VERY quickly because the surface hardening is gone. My vote: Replace the cam, lifters, pushrods, and rockers before it kills the crank with the bits from the ground off lobes. Learned that one the hard way.

[tucsonjwt]

I was going to say that I thought adjusting these went out with solid lifters.

I would note that when my 73 pushrods broke, I think I had a total of 2 broken pushrods and 1 or 2 bent rods. The cam was replaced along with the bad pushrods and it ran great after that. So, replacing the cam and all of the other parts as a preventive measure on an old truck which is not daily driver would not be my choice. I would roll the dice and hope that you have an experience like I had with my 73 - it just stopped moving while I was driving it in town and I pulled off into a parking lot, had it towed to a repair shop, and had about $400 in repairs.

Once you crack open an old engine you never know what you will find. I have read many posts here that start out as a troubleshoot minor dissection which turns into major surgery. Sometimes it is cheaper not to know the whole story. A full rebuild on a 454, even doing your own labor, can be pricey, and it is easy to make a costly mistake.

If you do go with a new cam, make sure you get the proper cam for your VIN and engine number - there is a difference between a truck cam and a car cam.

One the other hand, just pulling out all of the pushrods to see what condition they are in won't cost much, even if you have to replace all of them, and it might give you and indication of the camshaft condition.

[bnoon]

Originally Posted by tucsonjwt

If you do go with a new cam, make sure you get the proper cam for your VIN and engine number - there is a difference between a truck cam and a car cam.

Since when??? Weight/stall/gears and rest of the engine combo are all I've ever needed for a cam. Blocks are the same unless you get into the heavy duty or aftermarket stroker tall deck block.

[savatreatabvr]

Originally Posted by GRADYS Performance

Valves should NEVER be adjusted running.

What do you have for a cam and valve springs?

What are you using for oil?

Stock cam and valve springs. Using Quaker State 10 w 40.

[savatreatabvr]

Originally Posted by tucsonjwt

I was going to say that I thought adjusting these went out with solid lifters.

I would note that when my 73 pushrods broke, I think I had a total of 2 broken pushrods and 1 or 2 bent rods. The cam was replaced along with the bad pushrods and it ran great after that. So, replacing the cam and all of the other parts as a preventive measure on an old truck which is not daily driver would not be my choice. I would roll the dice and hope that you have an experience like I had with my 73 - it just stopped moving while I was driving it in town and I pulled off into a parking lot, had it towed to a repair shop, and had about $400 in repairs.

Once you crack open an old engine you never know what you will find. I have read many posts here that start out as a troubleshoot minor dissection which turns into major surgery. Sometimes it is cheaper not to know the whole story. A full rebuild on a 454, even doing your own labor, can be pricey, and it is easy to make a costly mistake.

If you do go with a new cam, make sure you get the proper cam for your VIN and engine number - there is a difference between a truck cam and a car cam.

One the other hand, just pulling out all of the pushrods to see what condition they are in won't cost much, even if you have to replace all of them, and it might give you and indication of the camshaft condition.

Good idea! I will pull the push rods in the next few days to see if any are bent. If not then I'm guessing some lifters may be shot because the rocker arm nuts are not all the same depth, meaning some have more threads showing on the stud than others. Other than flat cam lobes rocker arms that aren't all the same depth mean bad lifters right?

[savatreatabvr]

I will try a non-running valve adjustment when I check to see if the push rods are bent, any idea of what they're supposed to be set at?

[tucsonjwt]

I am not sure about truck vs. car cam on a 454, I just know that the first 454 cam I got was incorrect - was told by the mechanic that it was a "car" cam. I do know that some 454s had "RV" cams - maybe camper special like I had?

[GRADYS Performance]

Originally Posted by savatreatabvr

I will try a non-running valve adjustment when I check to see if the push rods are bent, any idea of what they're supposed to be set at?

The adjustment should be between 1/2 to 1 turn tight from zero lash at TDC for each Cylinder. Individual specs may vary from manufacturer but that would work with any stock or mild aftermarket cam and lifters.

[slotard]

Originally Posted by tucsonjwt

I am not sure about truck vs. car cam on a 454, I just know that the first 454 cam I got was incorrect - was told by the mechanic that it was a "car" cam. I do know that some 454s had "RV" cams - maybe camper special like I had?

While different applications have different profiles and therefore drive differently, they are generally all compatible.

If you need a new cam I'd do some research before deciding what to buy. You can decide whether you want better bottom end or more power up top.

I have a smallblock, but I have a Comp Cams 252H: http://www.compcams.com/Company/CC/c...x?csid=71&sb=2 hydraulic flat tappet cam with a cheap set of summit roller rockers http://www.summitracing.com/parts/sum-141506 and it works great as a truck engine. Of course, everyone has their own favorite brand and grind.

[tucsonjwt]

I have read that the RV cams are designed for more low end torque. Not sure what the camper specials had from the factory.

[tucsonjwt]

BTW - I got an email from Rock Auto which had closeout prices on pushrods, rockers, etc. and lots of other stuff. I am going to peruse for stock up on common maintenance items.

[savatreatabvr]

Originally Posted by tucsonjwt

BTW - I got an email from Rock Auto which had closeout prices on pushrods, rockers, etc. and lots of other stuff. I am going to peruse for stock up on common maintenance items.

I came across a basket case 454 at a yard sale, the guy said it was out of a tow truck with low miles. It all looked like good used parts so I gave him $50. If nothing is good I'll make a coffee table or something out of the block, lol!

[bnoon]

Have it checked for cracks and core shift, then send it to the machine shop if needed. If it's usable, heck of a score!

[tucsonjwt]

x2 on the 454 deal. Regarding just your pushrod check, you can get a set of new pushrods cheap, if you do need them, so why disassemble another motor that you can probably sell for more than enough to cover repairs on your engine.

[savatreatabvr]

Originally Posted by bnoon

Have it checked for cracks and core shift, then send it to the machine shop if needed. If it's usable, heck of a score!

What is core shift? I've been working on my own vehicles for over 30 years and I've never heard that before.

[slotard]

It's if the casting/machining was slightly off center. It would be that way since new for a given vehicle, not something that happens over time.