After about 100-150 miles on my new cam I decided to check lifter rotation to make sure everything was OK. I found that three of the intakes on the driver side were not rotating! :confused:

The cam is a new Lunati solid lifter 272/282 for a 454. This cam was broke in with all of the usual precautions, inner springs removed, plenty of Lunati cam lube, GM EOS, 2000+ RPM for 15-20 minutes, etc.. I checked the lift on the three lobes that were not rotating and all were within .0015 of what they should be. The lobes don't show any evidence of unusual wear and the lifters show a "butterfly" wear pattern rather than a circular pattern that the other lifters have.

I think I may have caught this before any serious damage was done, my question is what are my chances of replacing these three lifters with new ones and having them rotate like they are suppose to?

Any guesses why they wouldn't rotate from the start?

I plan on calling Lunati in the morning, just thought I would gather some info before hand.

Jeff

for me i would be checking soon after break in when i do cams if they are rotating............i have pulled out the lifters that was not rotating to my likings and replace them with a new one or two or three..............and rerun the cam like a break in period and recheck again.........i have not had to do it more then once for a cam............if it was mine i would replace them.....make sure the new lifters are convexed and drop them in....make sure they spin easy with your pinky and rerun the cam like a break in and then check the lifters after that.........

I hope your cam survived, keep us posted. Hard to believe the lobes made it 100 miles already without any major wear.

Originally posted by Jeff65SS:
After about 100-150 miles on my new cam I decided to check lifter rotation to make sure everything was OK. I found that three of the intakes on the driver side were not rotating! :confused: Jeff How did you check them? Tried to spin them with your finger and they were actually stuck in the bore or you pulled the intake manifold off and cranked the engine with a remote starter while watching the lifters? Can you remove two of them and put them base to base to see if they are still tapered on the bottom?

I checked by removing the valve covers one side at a time, marked the pushrod with a sharpie and started it up. The three intake push rods didn't rotate at all, all of the others were spinning alot. The three I took out (didn't remove intake)are convex on the bottom, I can see light between the edges when I place the bottoms together.

I talked with a tech guy at Lunati this AM, he suggested just replacing the ones that would not rotate with new ones. I going to get the lifters that have the EDM hole in the bottom for the extra oil.

Could the lifters bores not being machined true with the cam centerline cause this?

In hindsight I wish I had gotten a roller, I'm going to worry about this for the rest of the summer!

Jeff

Well they should have been spinning for sure with the engine running. Is it possible that the lifters were spinning and the pushrods not? Are the pushrods maybe bent? Since you removed the lifters, you now have the intake manifold off. Install the new lifters and rotate the engine by hand or with a remote start button and you should see them spin in the bores. I really can't imagine them not spinning but still be convex on the bottom.

A lot of the problems that I have been aware concerning lifter bores has been the number 6, 8 & 7 cylinders. I find it interesting that the intakes on one side are failing. Just for curiosity, did you put a cam button in when you put it together?

I saw an interesting post in www.superstockforum.com. (http://www.superstockforum.com.) It was by Dan Dvorak who operates a racing engine machine shop (Dvorak Machine) near Gainesville, FL and has built a ton of Stock Elim and Super Stock engines. Basically he said years ago when he started to bush and rebore factory lifter bores EXACTLY concentric to the cam bearing bore, he started having all kinds of problems with flat tappet lifters and cams failing because the lifters weren't spinning. His opinion is that the sloppier the factory alignment on lifter bores, the more likely they would desirably spin. Sounds strange. I'm wondering if the as-designed ideal factory lifter bore alignment is something other than perfectly concentric to the cam bearing bore.

GRN69CHV - no cam button. After much debate on this forum I decided to remove it when I installed the current camshaft.

Von - interesting, maybe one of the resident engine builders could lend their opinion.

Jeff

Originally posted by von:
I saw an interesting post in www.superstockforum.com. (http://www.superstockforum.com.) It was by Dan Dvorak who operates a racing engine machine shop (Dvorak Machine) near Gainesville, FL and has built a ton of Stock Elim and Super Stock engines. Basically he said years ago when he started to bush and rebore factory lifter bores EXACTLY concentric to the cam bearing bore, he started having all kinds of problems with flat tappet lifters and cams failing because the lifters weren't spinning. His opinion is that the sloppier the factory alignment on lifter bores, the more likely they would desirably spin. Sounds strange. I'm wondering if the as-designed ideal factory lifter bore alignment is something other than perfectly concentric to the cam bearing bore. =
What???
First, what exactly is meant by concentric to the cam bearings??
If he is saying right over the center of the lobes than I would agree because that isn't where the bores belong on a flat tappet cam.
If he is saying having the lifter bores in the wrong position from where they belong in relation to the lobes then I strongly disagree because two things happen.
One it completely screws up the intended cam timing on that cylinder if off in one plane & two if the bore isn't square to the lobe in the other plane then having the lobe ground on a taper to help spin the lifter is either defeated causing failure or increased to the point of having the lifter ride on a too small contact area which increases the unit loading to the point of failure depending on which way it is tilted.

I have seen lifter bores off so far that boring the hole to .875 would not clean them up even in small blocks so saying that putting them where they actually belong seems a bit,,,, odd :confused:

I wonder how much lifter to bore clearance plays into this. How accurate was GM with the diameter of the lifter bores? I've had some smallblocks that the lifters just slid in like there was a lot of clearance and other blocks that the lifters seemed almost tight. My Son's 327 we just finished sure seemed to be on the tight side but I never measured them. Hope the cam survives the teststand planned for it soon.

Originally posted by baddbob71:
I wonder how much lifter to bore clearance plays into this. How accurate was GM with the diameter of the lifter bores? I've had some smallblocks that the lifters just slid in like there was a lot of clearance and other blocks that the lifters seemed almost tight. My Son's 327 we just finished sure seemed to be on the tight side but I never measured them. Hope the cam survives the teststand planned for it soon. Bob,
If a dry lifter won't fall through the bore my preference would be to hone the bore.
If the cam is in you should be able to turn the lifter with one finger against it.

If you are concerned, when you start the engine pull the covers & if all the pushrods are spinning you should be fine.

Thanks for the advice Mike, I'll be watching the pushrods. And I also plan to measure the bores of my bigblock to see what the clearance is. The lifters did turn with my fingers ok when we dropped them in so hopefully all is well. I give you professionals a lot of credit considering the amount of measureing etc. that must be involved with a high buck competition engine build.

Originally posted by Wolfplace:
</font><blockquote>quote:</font><hr />Originally posted by von:
I saw an interesting post in www.superstockforum.com. (http://www.superstockforum.com.) It was by Dan Dvorak who operates a racing engine machine shop (Dvorak Machine) near Gainesville, FL and has built a ton of Stock Elim and Super Stock engines. Basically he said years ago when he started to bush and rebore factory lifter bores EXACTLY concentric to the cam bearing bore, he started having all kinds of problems with flat tappet lifters and cams failing because the lifters weren't spinning. His opinion is that the sloppier the factory alignment on lifter bores, the more likely they would desirably spin. Sounds strange. I'm wondering if the as-designed ideal factory lifter bore alignment is something other than perfectly concentric to the cam bearing bore. =
What???
First, what exactly is meant by concentric to the cam bearings??
If he is saying right over the center of the lobes than I would agree because that isn't where the bores belong on a flat tappet cam.
If he is saying having the lifter bores in the wrong position from where they belong in relation to the lobes then I strongly disagree because two things happen.
One it completely screws up the intended cam timing on that cylinder if off in one plane & two if the bore isn't square to the lobe in the other plane then having the lobe ground on a taper to help spin the lifter is either defeated causing failure or increased to the point of having the lifter ride on a too small contact area which increases the unit loading to the point of failure depending on which way it is tilted.

I have seen lifter bores off so far that boring the hole to .875 would not clean them up even in small blocks so saying that putting them where they actually belong seems a bit,,,, odd :confused: </font>[/QUOTE]I went back and re-read his thread. The word "concentric" is mine, not his. His words were to the effect of correcting lifter perpendicularity and alignment to the camshaft. I'm not saying I agree or disagree with what he said or his method. Just mentioning it here for the sake of discussion. His post is in the thread titled, "Poppels Lifter Tech and the Ripoff" on Page 2 of the "Stock/Superstock" forum. What I was trying to say was that I'm guessing he was correcting the lifter bores to something other than the designed factory alignment.

What year 454 block is this? When I redid my '71 402 block, we had to clean up the deck on one end to correct what the machinist described as warping in the block. We also had to line hone the mains. I have heard that the early 454 blocks as well as the 402 blocks had this tendency. It is not severe, but I would think the variance only needs to be a few thousandths to cause erratic lifter operations.

Just dropped off my 355 rotating assy to get it balanced. The guy doing the work has been machining/building round track motors around here for many years. We discussed lifters not rotating. His opinion was the possibility of microscopic high spots being raised with the environmentally friendly way blocks are cleaned these days. In other words the high spots are caused by the steel shot that the blocks cleaned with. He uses a small (single cutter) boring bar to run thru the lifter bores. Runs it thru just enough to knock the peaks off- not much at all he says. Easy to get carried away with it if you're not careful he mentions as well. Just something I ran across today. Dave H

The date code on the block is Jan. of 71. I can't recall much about the machining as I did it about 15 years ago. I do know that the block has never been through on of those Bake, Blast and Shake style cleaners that Dave H. is describing.

I suppose that it wouldn't take much tilt of the lifter off perpendicular for the contact point to move too close to the center of the lifter to cause rotation. I bet I could do a layout on cad to see! Lets see the lifter has a 36" radius (right?) ground into its bottom, the lifter is ).842 diameter and the lobe has a 0.0005 taper ground into it. Does anyone know what a cams lobe width is and are the lifter bores suppose to be parallel with the lobes centerline (perpendicular to the cams centerline).

I forgot, how much is the lifter bore offset from the center of the lobe.

Jeff

contrary to popular belief on this forum, many 454's have screwed up lifter bores from the factory. i've seen it on a couple, i've had one, and my buddy who owned a machine shop had several come through his shop that way. and no, it doesn't take much of a change in geometry to cause major rotation problems for the lifters. easiest cure for mine was.....go roller. ;)

My 454 build-up had the same problem. Two pushrods (#6 & 8 exh) were not spinning. Tried to get them started by rotating them manually while the engine was running - but to no avail :mad: !

Removed the intake and inspected the bottom of the lifters, their patterns were slightly different than the rest. Installed a couple of new lifters and broke them in. Again,the same pushrods did not spin and still dont - even after 3000 miles. Recently, checked the cam lobes and lifters and they were fine.

As Epistuff also hinted,its very much possible that the lifters are spinning and the pushrods arent. Lifters that dont spin dont last for a 100 miles ;)

IMHO, just replace the suspect lifters (EDM would be great) and break them in again. Also, plugging the oil filter bypass would be good insurance.

graemlins/thumbsup.gif

Originally posted by Dave H:
Just dropped off my 355 rotating assy to get it balanced. The guy doing the work has been machining/building round track motors around here for many years. We discussed lifters not rotating. His opinion was the possibility of microscopic high spots being raised with the environmentally friendly way blocks are cleaned these days. In other words the high spots are caused by the steel shot that the blocks cleaned with. He uses a small (single cutter) boring bar to run thru the lifter bores. Runs it thru just enough to knock the peaks off- not much at all he says. Easy to get carried away with it if you're not careful he mentions as well. Just something I ran across today. Dave H =
Dave,
Part of using the thermal process is deburring the lifter bores after blasting along with cleaning all the galleys by hand etc.
It's why a good shop isn't going to thermal clean your block for $30 or $40 dollars.
Thermal cleaning is excellent but like any other process it needs to be done correctly.
Any shop that doesn't chamfer the edges of the bores & broach them or run a ball hone through them or tell you to if all you did was have them clean the block should probably be crossed off you list of shops to use.
I don't quite understand what you are referring to about a "single point cutter" but I will assume he was referring to a hone or a deburring tool of some sort as it would be virtually impossible to run any kind of cutter through the lifter bores unless you are redoing them for bushings or a larger lifter.

GRN69CHV,
It makes no difference what year the block is.
I have found they all tend to move to a certain extent but the problems with the decks not being straight to the mains has more to do with the way GM machines the blocks than movement.
GM uses the pan rails to locate the block & a good machine shop will use the mains as a reference.
Problem is the mains may or may not be parallel to the pan rails so,,, the mains go one way, the deck surfaces head another way & the true 45 degree reference from the mains ends up another.
I have seen blocks that were almost .020 thou out end to end in relationship to the main bores & I can guarantee you this had nothing to do with warping.

On another note, when thermal cleaning first came out, all the Hot tank & jet washer guys were hollering that so much heat would distort the blocks & ruin alignment of the mains etc.
Truth is I have thermal cleaned a lot of blocks & have done so for a long time.
We "tested" probably 100 or so blocks before & after thermal cleaning & found some moved & some didn't in regards to main bores.
In my opinion this is telling me that some blocks had more stress built up in them that needed to be removed anyway where others for whatever reason seemed more "stable" & the "relaxing" that was going on in the oven was probably a good thing. ;)

Novaman, thats exactly what I plan to do. I got a new set of lifters today via UPS. They have the small oil hole in the center of the bottom. I plan on replacing the three that weren't rotating and see what happens.

I remembered that I had the old cam and lifters that I removed this winter. The intake lifter from #3 cylinder shows the same butterfly type wear pattern that the new #3 intake lifter has. So the block must be the problem. Never went flat though, after 2+ years of hard abuse in my jet boat.

I would think that the pushrod may not always rotate with the lifter on a hydraulic cam because of the zero lash but on a solid lifter cam the lash sould allow the pushrod to follow the lifter.

I'll post tomorrow after I get it running again to let everyone know what I wind up with.

Thanks

Jeff

I hate to say this but one of the possibilities in causing the lifters not to spin in the camshaft.If it was ground improperly or perhaps an old stone or improperly dressed stone was used the proper taper may be missing from any given lobe.

Yet I was digging around some old ancient stuff hanging around work and found an old lifter and grabbed an new lifter and it sure seemed to the naked eye that the crown on this old NOS ( new old stock ) lifter was abit taller and rocked more than the newer one. I didnt have anything proper to measure them .. just eyeballed it.

I'm looking at an old Isky flat tappet I have had for a couple decades that was ground on a CWC core and.... it dont look the same as these newer cast iron cores that everyone is useing these days....

Something is different with todays stuff.

Just a thought.... bad lifter bore alignment and all but I have to wonder just what sort of percentage of warrenty work Detroit had to do that was due to camshaft/ lifter failiers when these engines were new way back in the day ?.... My guess is that it would have been very little... So if Detroit wasnt killing many cams with out of alignment blocks when new.... whats causeing them to kill cams now ?....... Or did Detroit back in the 60's and early 70's kill alot of cams ? Back in the mid 50's it was a problem... but as far as I can tell by the late 50's the problem seemed to stop.

Hey Mike(wolfplace), the shop that originally did the boring/cleaning of the block was a local Napa chain store. I bought this as a non-performance rebuild ready to go together from a friend of a friend. Now it's 3 1/2 years later & I'm finally getting around to putting it together. During this time frame I've been reading/learning. graemlins/clonk.gif If I had it all to do again, I'd avoid the kit from Summit and take it straight to the shop I'm now using and avoid the Napa store completely. I'm not saying that Napa is bad for a straight rebuild,they just don't offer what I'm looking for in a machine shop. The cutter/boring tool used to knock off the peaks of the cleaned lifter valley looks to me like a boring bar for a Bridgeport manual mill.The cutting insert runs almost the full length of the tool and there is only one of these inserts on the tool. The insert looks like a long single-edged blade. I don't know if maybe this is the actual cutting tool he uses when taking bronze bushings to final dimension when bronze bushings are installed in lifter bores. :confused: This machinist seems to share some of your ideas/thoughts but goes about them in a slightly different manner. And he's only 30 miles from my home ! :D I'd like to stop by your shop sometime & pick your brain and talk 'bout racing stuff But it'd take too long in the $600 beater daily driver. graemlins/waving.gif Thanks for your help with all these ideas/questions I have. graemlins/thumbsup.gif Dave H

Dave,
That makes a bit more sense,, sounds almost like some sort of a tool that "scrapes" the surface of irregularities without removing much if any material??
I use a broach & ball hone on them.

I have tried a bunch of different methods on the bronze bushings & the best of the bunch seems to be broaching the bores & then honing to final size.
The broaching brings them to within about .0005-.001 of final size so you are not in there screwing the bore up to long with a hone ;)
It also "sets" the bushings extremely tight in the block.

Bottom line, your point is well taken about places that do not finish the bores after thermal cleaning graemlins/thumbsup.gif

I had a customer that bought one of Napa's "rebuilt" short blocks for his ranch truck as I don't build "$699 engines" & couldn't get some of the lifters in the bores without almost forcing them,,, same deal, the bore edges were hammered, probably from blasting after thermal cleaning & not finished.
The Napa store told him it wasn't a problem as long as he could get the lifters in they would "loosen up in service" graemlins/sad.gif