just got the engine back in the 83 and got her wired up from a cam change............now it has a lot of pop to it.......aka out the headers......................i adjusted the valves with the spining push rod method......but i can all most swear an intake is hanging open.......plus ive yet to time it with a light yet........all i know is it pops and has really really shittty throttle response.........any body have any ideas on what this could be? all help is appreciated

 

Check the timing, sounds like it is firing as the exhaust port is open.

 

as in on the dizzy? or on the crank to cam?.........i advanced it 4 degrees when i put in the dizzy........does that hurt anything?

 

timing issue. start by pulling the distributor and reinstalling it at tdc

 

tryed that

 

Stupid question but are you sure you got the plug wires especially 5 and seven on correctly? It happens.

 

If you set your valves by spinning the pushrod and turning the rocker nut
until you can't spin the pushrod...then added an additional 1/4, 1/2, or 3/4
turn , you can rest assured one or more valves are hanging open.

The proper method to set valves is to use a dial, or a feeler gauge. If you
don't have either, you can use the zero lash procedure and baseline method.

After you have ensured the lifter is on the base of the lobe, tighten the rocker
nut until there is zero vertical movement of the pushrod (not zero spin).

Once you have taken up all the "lash" (vertical slack), then you can turn
the rocker nut an additional 1/4 turn (~ 0.020" preload for roller cams) on
standard studs.

Redo the entire valve train. Trust me on that note.

 

Dead on right here. You probably have several valves with the plunger bottomed in the lifter.

 

Adjust the valves with the engine running. All the rest of that "spin the push rod" and "slack" type stuff is just barely good enough to get you into the ballpark before initial startup, unless you're quite good and experienced at it. Since it already at least runs, time to move past that. Do it the right way (running), and then if it still has trouble, at least that one variable has been eliminated.

 

So, if the cam developer wants a certain amount of pre-load, how do you
know how much you've set using this procedure?

Do you set brand new out of the box flat tappet hydraulics this way too?

 

Of course. If the cam developer says "¼ turn past zero lash" or "½ turn past zero lash" or "per factory settings" or whatever, then that's what it should get. Find zero lash with the engine running, add the desired preload. Not rocket science.Of course. I set them using the "jiggle the push rod" method on the engine stand, which I've done enough times that I can usually get it right unlike someone who hasn't built lots of motors, and then if it seems appropriate (as it clearly does in this case), set them with the engine running. The "jiggle the push rod" method requires a certian amount of judgement and experience to get right, so for someone who hasn't done it lots of times, it's easy to get it a little off. No big deal, just set them running afterwards.

 

Well, a cam designer would never use the terms 1/4, or 1/2 to define lash,
or preload. You would have to use some sort of measurement device (dial,
or feeler). I don't know why you would want to set , or find zero lash with
the engine running?

Zero lash should be found on the engine stand to avoid damaging the
lifter retainters/seats. Why would you want to run a motor with a hydraulic
lifter with any amount of lash?

So , you're admitting that you set pre-load on brand new flat tappet cams while the
engine is running?

Do you understand how to break in a flat tappet lifter/cam set?

Again, how do you know the amount of pre-load you are setting with the
engine running?

 

Really? http://www.compcams.com/technical/Ca...07/375-378.pdf Go to step 11.Sure. Right. Of course it should. What if the engine isn't ON A STAND any more?I don't. The OP doesn't either. I thought that was why we were talking about adjusting them in the first place?Yes, of course.Yes, of course.By finding zero lash FIRST (back off the nut until it ticks, then tighten slowly until it quits ticking), and then adding the desired preload. Same way people have been adjusting rockers on hydraulic flat-tappet cams in adjustable rocker systems since they first came out. "Desired preload" might be expressed in thousandths (very rarely, since most people wouldn't know what to do with that), which is then a simple matter to convert to turns of the rocker nut according to its thread pitch.

What's so hard to understand about this? Where are you going with this? Don't YOU know how to adjust rockers?

 

You have a measurement device, the rocker nut. A 3/8 stud has 24 threads per inch, or so each flat you turn a 6 point nut is .007". That's more than accurate enough.

Zero lash is found while the engine is running by backing it off until the rocker starts to clatter, then turning it back until the point where it just stops. After that, you turn it down to the correct amount of preload.

 

you sir, should not be giving technical advice! By using that method on
a flat tappet hydraulic, you've just sacrificed the integrity of the camshaft,
or begun the damage process.

If you knew how to break in a flat tappet cam, you would see how this
is totally incorrect.

As for setting valves while the motor is in the engine bay, you to do it
the exact same way. Engine off. Rotate the crankshaft.

You should pop over to some tech forums that I'm moderating (like Speed Talk), posting info such as you are would get your posts removed in seconds
with a warning.

This site needs a technical moderator to prevent incorrect procedures
from ruining people's investments.

This is not the first post that I've read in which you've suggested terrible
practices.

You should get your face out of the magazines and get into some engine
building classes/schools, or apprentice from a professional.

 

Go to www.camaros.net and ask the question over there. The guys over there are much better at diagnosing carbureted engine issues than most of the users on this website.

To adjust your rocker arms, just loosen the nut, jiggle the push rod up and down until it won't jiggle anymore. After that tighten the nut either 1/4 to 1/2 a turn on the wrench. Some people say 1/4 some say 1/2. That will get you very close to having things adjusted. If it still is back firing I would look at your valve springs themself. You could have a broken valve spring or your spring pressures aren't correct. Also I would pull the timing cover off and make sure you installed the timing chain correctly.

 

Really!?!?!?!? Excuse me? Aren't practically all stock cams flat-tappet hydraulics, before 1987? Since when did the method that's been used for all these years on all these millions of cars by all these millions of people suddenly bcome destructive?

What does cam break-in have to do with ANY of this?

Here's a typical description of valve adjustment on a running SBC (as opposed to, during build-up). http://en.allexperts.com/q/Chevrolet...-305-chevy.htm Google is your friend.

How many web sites am I going to have to post for you, until you're educated enough to be ready to work on a car? Go buy a car and a set of tools, and a book or something. You'll learn faster that way.

I'm really not interested in having you follow me around and trying to pick fights; although so far, you've done a pretty fine job of making a fool out of yourself that way. As several wise people have been quoted as saying, "it's better to be thought a fool, than to open your mouth and remove all doubt". Doesn't seem to be much doubt left here.

 

That's great, post links from garbage sites.

You obvisouly don't know how to break in a flat tappet cam, because
if you did, you wouldn't ask silly questions.

Here's a hint: When the engine is fired for the first time, the RPM should
never dip near idle speeds.

So...you are telling me "Mr. Know it all", that you find zero lash with the
engine running and pushrods slopping around. You also set pre-load
using 'the clacking' method.

Three things wrong already:

1. No load on the lifter seat can damage the retaining clip
2. Slack between pushrods and lifters bouncing around causes damage
3. By the time you've found lash and set your pre-load, you've probably
wiped a lobe, or ruined a lifter.

Look up camshaft break-in for flat tappets and you'll figure it out quick.



Should I buy more books and put them next to my degrees framed up
on the walls of my shop? I bet you I've set more valve trains this year
alone than you have all your life.

You would be happy with my toolbox and tools. At least that way, you
could use compressed air to remove valve springs instead of ruining someone's
valves and pistons.

Maybe you could come to my shop and show me and my partner how to
build a 7 second car? Better yet, and more do-able...pop over to Speed
Talk and tell them how you set valves.

Then you'll get NASCAR builders, NHRA/IHRA Prostock builders, Camshaft
Developers, and GM Engineers laughing in your face.

I'm not interested in having you assume to correct every post I make with B.S.
magazine and interent myths.

Come to me when a choke causes engine backfires AND run-on.

Have a nice day, and try to learn something from these posts.

 

Thank you! I'm having a WONDERFUL day, in spite of all this.Right... fundamental rule of cam break-in. What does that have to do with the issue at hand? I thought the issue was ADJUSTING THE VALVES?No, I don't. Don't put words in my mouth. I find it with the engine sitting still and I generally use the "EOIC" method on a hydraulic cam, and the "180°" method on a solid. However, on an engine with hydraulics that's ALREADY been adjusted that way and is RUNNING, if it's not quite right, I use the "engine running" method.And you think I'm any more interested in having you follow around behind me and pretend to "correct" my posts with a bunch of BS and hate and "I 'know' more than you" and "my shop is better than yours"? That kind of talk doesn't help anybody here, doesn't help solve any problems, and mostly just irritates everybody.

You can be as rude to me as you like; doesn't make you right, or me wrong.I can't be bothered. It's already happening. But you've already made a fool out of yourself over on that one too trying to send that poor fellow on a left turn down the dirt road and into the weeds, like this guy here, chasing something unrelated to his actual problem; so there's not much left to say about that one either.

Have a nice day!!

 

You're not making sense, and just for the record, you jumped on me within
a few posts of my registration.

Apparently you still don't understand the break-in method, and the fact that
you are adjusting valves using the ticking method while the engine is running.

I've already pointed out three reasons why you need to set the valves properly
before firing the engine.

You are setting the valves before the cam is properly broken-in.

Either that, or you are breaking in the cam with incorrect preload/lash which
is equally damaging.

Rather than push these absurb methods on beginners, why not teach them
the right way with industry proven results so they too can become better.

You can't get ahead in life sticking with status quo. If the OP doesn't appreciate
a better method to set his engine, then my work is done here.

I think you're the only one that thinks I'm a fool at this point. That doesn't
bother me coming from somone who suggests putting the piston as close to
the valve as possible and smacking the retainer with a socket and hammer.

You probably check piston to valve clearance with play-dough don't you?

 

D00d, give it a rest, OK?

Flaming people in public behind internet anonymity doesn't make you a "big man".

I know perfectly well what the break-in method is. Learned quite a bit about it when I was doing contract engineering work for Comp, which was probably before you were born.Yes I'm perfectly aware of that. I've also pointed out at least as many times that once they're roughed in and close enough for the motor to run, there's an easy and fool-proof way to set them, that people have been using for as long as hydraulic lifters underneath adjustable rockers, have been around. It's worked fine now for well over 50 years.

I'm REALLY tired of getting picked at over this. If you just can't let it go though, I understand, I've felt the feeling of defeat before too, and even of making a fool of myself over something trivial, like you're doing to yourself. I hate it. That's why I go to great lengths to make sure that I make as few mistakes as possible; and that I don't try to tell people NOT in race shops that you have to have dial indicators and feeler gauges to adjust hydraulic lifters. Even though "in a perfect world", maybe that's how it would be done. But in this world, we do it with the engine running.No, in fact I don't; I use a solid lifter and "check" springs. Although, for people who don't HAVE that stuff, Play-doh makes a better substitute than doing NOTHING.

 

what i done it the zero lash method, aint it? tightin the studs so the push rod still spins, but there is no play in the rocker arms......oh and the cam has been broken in before, it was the one in the engine before i put in the seat shaker cam

 

The problem is, identifying zero lash.

If you have a lifter with no oil in it, and a lifter that's FULL of oil, it's almost guaranteed that they will "feel" different by the "spin the push rod" method. The empty one will have only that weak little spring in it opposing your "spin", so when you tighten that one, you'll keep tightening and "spinning" until that plunger is all the way bottomed, before it begins to oppose your "spin". Then, put some additional tightening on it, and you've got a valve permanently hung open. But the full one will work more or less like you expect it to.

That's what I was referring to earlier on, about how it's easy to get it mis-adjusted. There's a fair amount of judgment and prior experience involved, and it's not easy to hang upside down over the fenders and get in there and see or feel stuff, with the motor in a car; so it's REAL EASY to make a mistake.

Which comes right back around to, those other methods, while perhaps "ideal" and "preferred", are also not always PRACTICAL or SUCCESSFUL.

OTOH, the method of adjusting them while running, is about as near fool-proof (me-proof? ) as anything can be.

Ignore all the pointless bickering and name-calling. I'm really sorry it came to that, but I can't take all the blame. However all that may be, focus yourself on results. Adjust your valves with the motor running.

 

got it running today for about ten minutes.....sucking air from a vacum fitting on the carb i over looked.........................ran good....needed the carb tuned a lil to have crisp throttle.........it quit and wouldnt start back, i traced the problem to the plugs not firing, the coil wire has fire so i figure the dist. cap must have got broke when i installed it, maybe a trip to oriellys and a new cap and coil will fix this..........wrong. its firing now but it still wont run, you can put the distributor adjustment anywhere from the firing wall, to the advance bell touching the carb........it just spins like the timing is backed all the way off. Any ideas guys?

 

Not sure what that means?

Put the motor to the point you want your static timing to be, like 10° BTDC or whatever, making SURE you know where TDC really is (not necessarily the timing mark...). Turn the dist to where the star wheel points line up. Your ignition timing will now be within a few degrees of "right"; close enough to run, anyway.

Then, check for spark at a plug.

 

so, put the no 1 piston at zero and the pointer on the dizzy to point at the number 1 plug wire? i really cant see the problem b/c it was running good then sputtered then quit and wouldnt crank back.......it lost its spark, i fixed that now it still wont run
----------
ive tryed that before and it just made a mess

 

Well if the car turns out not to need valve adjustment at all, worry about it. Find why it has no spark and move on.

Or, might have fouled th eplugs. Might be worth a look.

 

Defeat? This isn't a game like Snake and Ladders my friend. This is engine
building 101. There's no hiding here; all you have to do is click my profile and
you'll learn all you need to know.

You couldn't possibly be an engineer and work for the Comp Cams cam division
with valve setting techniques that you boast. The only contract work you
might have done for them is "smoke and mirrors", or lawn care because Comp
sure as hell wouldn't suggest your methods.

If you really want to impress all of us, why don't you post the cam break-in
procedure for flat tappet cams. I can't wait to read it!

Once again, if you read the history of all the threads (including this one), it
seems I have replied first and then you bark back with some nonsense.
Note above, my reply to OP's question outlines a potential problem followed
by a correct valve setting technique. No special tools required either! You
don't NEED a dial, or feelers to set valves. If you want to do it properly,
then take the plunge and spend $20.00 for a set of feelers and learn the
proper technique.

Now, don't take my word for it. If anyone here thinks running the motor
is the better way, then please call up Comp, Crane, or any cam developer
and ask them about the "clacking method while the engine is running".

If they ask whether it is one of their cams you are setting, be sure to tell
them no as they wont warranty the cam once you wipe a lobe or destroy
a lifter..

P.S. Sofa, you keep blowing my mind with your engine building expertise.
Can you please explain why you use a solid lifter, or the need for any lifter
at all when checking PTV? Can you also tell me how you're measuring the
PTV clearance with your skills?

 

Not quite. If the rocker arm does not move side to side easily, they are too
tight.

The up and down movement of the rocker should be none, however if you
turn them side to side, they should feel quite loose.

 

calm down guys, fighting over the internet is like the special olympics, even if you win your still retarded

 

No.No.

If you don't already know, then arguing with me about it here and continuing to make a fool of yourself won't make any difference. Go get a book and read it.

Have a nice day!!!

 

Well, since Sofa didn't post the correct cam break-in procedure, here it is
from several sources:

http://www.usaimports.co.uk/Mopar_Te...raulic_cam.htm

http://www.holley.com/data/Products/...al/INST150.pdf

http://www.compcams.com/Technical/In.../Files/145.pdf


You can see that if the pre-load is not set before start up, and the rockers
are adjusted too loose, damage is highly likely. Each procedure specifies
this clearly and emphatically!

This is most important and applies mainly to flat tappets, however hydraulic
roller lifters also benefit from having a load on the seat before firing the
engine.

If the engine is on a stand, or in the engine bay, the pre-load is easily set
with the EOIC method, or the baseline method. Once you have taken up
the lash and set the pre-load, there is NO need to back off the rockers
and listen for clack while the engine is running. This is damaging to the
lifter, and cam lobe. Not to mention, you are creating double the work,
and messing with measurements you have already performed before the
motor was started up.

Anyone who tells you otherwise has no clue about cam design, or engine
set up.

Hopefully you have all learned something valueable that will save your
engine parts and prolong the life of your engine.

 

I can certainly agree with that. I'm no expert, but I have installed a couple of flat tappet cams before. I soak all my brand new tappets in oil and work the plunger with a pushrod to prime them before installation. Never use old tappets on a new cam. Use plenty of assembly lube. I adjust rockers by the "no vertical slack" method. Spinning the pushrod can be misleading. Set the timing to make sure the engine fires right off the bat, no extended cranking allowed. Keep revs at least 2000 RPM for 15 or 20 minutes. Rejoice.

 

Wow this turned into a flame war. I use the method posted in the link above for setting a cam never had an issue but I dont do it before I preoil the sytem I dont see a need. I do have fingers and eyes that work well engough to know when lash is set and having a very small amount of lash isnt a bad thing thats why with hyd lifters the oil takes up the rest of the lash when the engine is running.

I dont see why especially in this case setting the valves when the engine is running is frownd upon. It works really well and is a near fool proff method of doing it and yes several GM books and others reccomend doing it this way some say do both.

Ah but what do I know Ive never worked on an engine before.

 

If you hear clacking on a hydraulic valve train, then you have lash. Lash is not ideal because the retaining clip could get damaged, and you have valve train parts smacking into each other.

It’s never a good scenario to have roller, or flat lifters bouncing on the cam lobe at
any time. This applies to any camshaft whether new , or old.

On brand new cams and lifter, especially flat tappets, the lifter must be under
Constant load during break-in at high RPM. The reason for this is due to the
Design of the lifter crown and cam lobe.

Each of them a ground with an offset which causes the lifter to spin as it rides
The cam lobe.

If the lifter stalls due to low RPM, or lack of pre-load, the offset grind will wear
Off and damage the crown. This could cause the lifter to permanently stop spinning
And wipe out cam lobes.

 

Yeah that was sort of unnecessary, wasn't it.... especially since it turns out not to be the OP's problem, anyway.

It'll be interesting to see if he gets his problem sorted out. Sounds like he's got a bit of checking around to do that DOESN'T involve the valve train at all.But hey... what do those guys know about cars, anyway?

 

I didn't know GM designed cams?

 

New GM cars off the assembly line never had their engines broken in. Millions of GM cars came off the assembly line and never had their cam lobes whiped off.

Personally I used the break in method, however I think its more important that the engine be broken in an oil with a high zinc content. Oils today don't have the zinc content that they used to, which is why cams today will go bad.

 

Perhaps that part is being overlooked by some.

Personally, I didn't know anything about "breaking in" a cam for decades. As wrsjr pointed out, the factory never did any special cam break-in procedure. Their problems seemed to be from poor QC, not lack of break-in. I've never wiped out a cam in my life (which is about double in length compared to a lot of members here).

The break-in seems to be more of an issue when you get into higher lifts and stiffer springs. Comp will tell you to break in the cam with the inner springs removed. My engine build resource tells me to use ARP thread lube on the lobes and lifter faces and not worry about it. There seems to be a consensus on not using synthetic oil during cam break-in (I hate putting petroleum oil in my engines, but I do it for cam break-in). The factory didn't start using synthetic oil as factory-fill until roller cams were the norm.

jay_d, I'd suggest you go back to the beginning and double-check everything. Since this was a cam change operation, make sure in your mind that the cam itself was properly aligned (did you do the timing sprockets dot-to-dot, or both at 12 o'clock?). Make sure all of the spark plug wires are going to the proper cylinder. If you think you've got a rocker too tight, loosen them all up - it won't hurt anything to run it a little loose until you can make sure it's running right and then you can go through and adjust them "properly". I can't imagine a too-tight intake causing popping through the exhaust, though.

There's always the possibility that you got a bad cam. Not likely, but not impossible. Go through the basics first, though.

 

I almost hate to bring this one back from the grave, but........just in case anyone reads all this about adjusting valves, I am going to post it anyway. I emailed comp cams about this stuff a few days ago and they finally replied see below:
*****************
From: "Comp Cams" <compcams@compcams.com> Add Mobile Alert
To: ljnowell@yahoo.com
Subject: FW: COMP Cams Feedback
Date: Mon, 10 Mar 2008 14:43:22 -0500



Yes you can adjust the valves while the engine is running as long as
the
engine is a hydraulic camshaft

Thanks
Buggy



-----Original Message-----
From: Comp Cams [mailto:compcams@compcams.com]
Sent: Friday, March 07, 2008 1:48 PM
To: BUGGY JOHNSON
Subject: COMP Cams Feedback

From: ljnowell@yahoo.com
Message:
I have a quick question.Is it ok to adjust te valves on my sbc with the
engine running?
***********************

As to comp cams not recommending this procedure, that pretty well speaks for itself.

 

Wouldn't this show that a "proper" break in is not required? As for adjusting valves with the engine running, I've done it a few times as per sofas directions and it's always worked right without anything breaking.

 

There you go, some professional advise to back up what Sofa and many, many, MANY others have done for the last 50 years without problems. Its a common and perfectly acceptable method. I've always made valve adjustments (break-in aside, as it has nothing to do with this) on my hydraulic cams exactly the same way Sofa mentioned - I actually learned the method from him a long time back - and I've never had ANY problems with this method. Not on a stock SBC with the flimsy 'sheet metal' rockers, wimpy stock valve springs, and stock camshaft, and not on my big beefy Comp XE cam, Comp hyrdaulic lifters, Comp Pushrods, Comp Pro Magnum rockers, and the springs that match the cam specs. The email posted in the quote above was almost word for word the same one I got from Comp after I did my cam and heads, and they also told me that using that method of adjustment will NOT void the warranty. Period.

As for the 'checking PTV clearance with a solid lifter' - I know the method, I've done it, and it works. Theres nothing wrong with doing it that way, and no reason not to. Of course there are other methods of measuring clearance, just as there is adjusting valves, but just because someone doesn't use the EXACT SAME METHOD as you do does NOT make it wrong.

Theres no reason anyone has to get into it like this with another member on this board. Not everyone is going to agree on everything, and not everyone is going to use the same means to get the same end result. There is more than one right way to do MANY things on MANY cars - some will use one method, some with use another - thats no reason to start sharpening your claws like you are. Respectful argument is fine, but this is a whole different animal - KNOCK IT OFF!!

 

That's fine, and I can link you to a thread from camshaft developers who say
not to adjust hydraulics with the engine running.

I'm sure the debate has cooled and myself and Sofa seem to co-exist
well on this board since the incident.

Feel free to use which ever method you think is best. I personally do
not use the 'engine running' procedure on engines I build based on the
facts presented to me.

Peace.

 

well....it runs now and i know how to adjust valves because it doesnt pop anymore..........the spinning push rod method is the cleanest way i know to do it(running a hydraulic lifter of course) my vavles where right from the start i just over looked a small vacum hole, if you are running the engine for break in on a crate thing id recomend adjusting when running......but it makes a huge mess when in the car.......did it all the time on my dirt track car, im no chevy master, but i did manage to build this one and it runs good, doesnt smoke, doesnt blow by, and will haul *** even with my truck cam........engine building has been a trial and error thing for me, the first one i built siezed a wrist pin, second one spun a bearing, third time is the charm i guess cause it saw 7000 rpm last night according to my tach (which is a autometer), and stayed together

 

Good to hear you got it all sorted out Tracking down problems like that can be a real PITA.