i have a 87 camaro 5speed 305 and im rebuilding the top end.

my question is do i have to adjust the valves witht the engine running?

my twin brother (a 5.0 Fastback mustang owner) told me that i had to adjust it with the engine running and i just adjusted then with the engine off.

is this true?

 

valve lash adjustment does not have to be done with the engine running.
Rotate crankshaft until mark on torsional damper aligns with center or ``O'' mark on timing tab, attached to crankcase front cover, and piston of No. 1 cylinder is at top dead center of compression stroke. This may be determined by placing fingers on the valves for No. 1 cylinder as timing mark on damper nears the ``O'' mark on front cover. If valves do not move, engine is in the No. 1 firing position. If valves move, the engine is in the No. 6 firing position and should be rotated an additional revolution.
With valves in No. 1 firing position, adjust exhaust valves 1, 3, 4 and 8, and intake valves 1, 2, 5 and 7 as described in step 3.
Back out adjusting nut until lash is felt at pushrod, then turn adjusting nut inward until all lash is removed. When all lash has been removed, turn adjusting nut in additional one turn. Zero lash can be determined by rotating pushrod while turning and adjusting nut.
Rotate crankshaft one revolution, until pointer ``O'' mark and torsional damper mark are aligned. With engine in this position, adjust exhaust valves 2, 5, 6 and 7 and intake valves 3, 4, 6 and 8.
Install rocker arm covers, then start engine and check idle speed and ignition timing.
READJUSTMENT
The following procedure, performed with the engine running, should be done only in case readjustment is required.

 

i fully agree with one92rs , but i prefer final adjustment with engine running . thats just my thoughts . good luck .

 

Hope I can get some advice here on an '88 305 TBI that was running before I undertook to replace head gaskets and clean up the valves.,,

I resurrected an older thread because it has nearly the exact valve adjustment procedure that I used two posts above this current post. The only thing I did differently, based on a procedure found elsewhere, was that instead of looking for lash in the pushrods, I used rotation and tightened 3/4-turn after it felt like the rotation became more difficult. That's a procedure which appears in a lot of places.

Net result is the engine will not start, despite, per instructions, having spark set to zero advance with the relevant connector disconnected, then a rest period with the battery disconnected to clear the computer's memory, then attempted starting with the connector and battery reconnected.

So I'm wondering whether I got the valve adjustment far enough off using pushrod rotation difficulty as my reference that the engine is not compressing or not lifting the valves enough -- I think it's lifting the valves far enough because I don't hear clacking, so I would tend to suspect that, if anything is wrong with the valve adjustment, they would be too tight, causing compression loss. In fact, there is some blowback of raw fuel through the throttle body when the throttle is opened during cranking that does not look right to me.

I hate to have to static-adjust the valves again because of the difficult of pulling the accessories off the engine to allow the valve covers to be removed (I'm sure that a lot of you can relate to this difficulty). What do you think? Does this sound like a valve adjustment issue? The engine was running before I took it apart, and as I said, I have spark and the timing appears to be set according to spec.

Many thanks for any help you might provide.

 

Yes.

The reason is

Happens to just about everybody, especially those who don't already have lots of experience. Problem is, you can still rotate the PR, LONG AFTER zero lash is attained, thus making the lash WAY too tight.

Second possibility for error lies in how you located (or didn't) the exact zero lift point for each lobe. That error tends to make the valves too loose.

So you end up with one source of error making them WAY tight, and another source making them a little bit loose. End result is, you have no way to have any reliable clue as to where they ACTUALLY ARE.

Re-do it. Except this time, do them ONE VALVE AT A TIME, rotating the engine by hand in 90° (one cyl) increments. Locate a cyl whose exhaust valve is just beginning to open as you turn the motor by hand; rotate the motor by hand slowly until you see the exh valve on the next cyl in the firing order (e.g. if you walked up to it and noticed that #4 exh was opening, continue turning and watch #3 exh), and at that point, adjust that cyl's intake. Go through all 8 of that kind of valve, rotating it by hand 90° at a time. Repeat watching the intake valves, except this time watch for one that's closing; and just as the int almost reaches fully closed, adjust that cyl's exh. Once again, go through the motor rotating it by hand exactly 90° at a time, through the firing order starting wherever, until all 8 are done. Tighten them until the push rod JUST BARELY stops being able to be loosely banged up and down (NOT rotated) between the lifter and the rocker. IOW, JUST BARELY take out all the slack. Then once all 16 are set to zero lash that way, add ½ to ¾ turn of preload.

When I say "rotate by hand", that means either put the car in high gear parked on a hill facing down with the dist 12V unplugged; or, use a crank turning tool - NOT the damper bolt - to turn it. If you use the damper bolt, you can count on your next post here being "how do I fix a stripped crank snout" or "how do I get a broken bolt out".

 

Thank your sofakingdom: that makes a ton of sense, given that the engine fires every 90 degrees but I redid it between posting and when you posted, via the previous (180-degree static) method but with pushrod lash instead of pushrod rotation as the base state, with 3/4 of a turn put in after zero lash. I then successfully started the engine for a moment, but I STILL HAVE ISSUES FOR WHICH I'LL PUT THE QUESTIONS IN ALL-CAPS BELOW. Hopefully you and/or others will help me out -- I'm right on the verge of getting it going, still have the valve covers off as of tonight (California time), and have two critical questions, below.

By the way, the 90 degree method makes more sense due to 90-degree firing and I'd like to use it in the future, but: 1) I don't have a crank rotation tool; 2) the plugs are in and I've never had success rotating to accurate spots by hand (except at TDC with some work); 3) I got it running between your post and mine using the 90-degree method I described); 4) I really need to get this, my daily driver, on the road ASAP, so I'm hoping the most recent adjustment will get me there.

Here's where my issues remain, other than perhaps valve adjustment: 1) I did not want to actually adjust the valves with the engine running due to a fresh cleanup and no gadgets for keeping the oil near the valve gear; when the heads were taken apart, I was not here, the work was done by a fairly incompetent handyman I use who immediately forgot where the parts went; 3) I have not had a small block chevy's valves open since the early seventies; and 4) both the vague manual I have and online resources have been of no help in addressing the two big issues below.

The two big issues, related not having disassembled the heads myself:

1) I do not recall and have been unable to find references as to which valves, intake vs. exhaust, are to receive the bearings in the valve spring stack. I put them on the exhaust because it seemed to make better sense that graduated rotation in use would keep the hot spots moving and reduce valve burning. I put the flat sides of the facing the springs. PLEASE TELL ME WHETHER I GOT ALL THAT CORRECT.

2) Here's what seems to be the big one. I assembled the valve spring stacks as follows, from top to bottom: spring, bearing (exhaust) or similar looking item that has no bearing (intake), and finally, the 16 sheet metal items that have a big opening and a small opening opposite. I assembled these with the small end towards the rocker with the bearing or similar item stuck into the big end. I had to do what seemed to be more metal removal than cleanup to get the bearing into the sheet metal pieces although at the end of the process the bearing seats into the sheet metal pieces and still rotated. For the intakes, though, the sheet metal pieces fit only loosely over the intermediary pieces that look similar to the bearings. When I started the engine for a few seconds with the valve covers off, it seemed to me that these were clattering unduly, and having them loose like that just doesn't look right to me but I can't visualize another way to put them together that makes sense. SO PLEASE LET ME KNOW WHETHER I SCREWED THIS UP AND, IF SO, HOW TO MAKE IT RIGHT. Again, my vague manual and online resources did not help me with this.

Thanks again!

 

I'm not sure what you mean by "bearing"; but, if it's the thing that's about .100" thick, it's a "rotator", and it came off the exhausts. It is useless. Throw it away and replace with .100" of shims under the spring.

Same for the oil splash shields: worthless, dead weight. Throw them away.

Both of those parts were introduced many years ago, to deal with issues prevalent at the time (the splash shield in the 50s before it was possible to make valve guide seals that worked, and the rotator about when unleaded gas became commonplace in the early 70s, to prevent seat erosion from the valves staying stationary, although they are highly ineffective). Both of them have been on factory motors for so long now that the people who knew what they were put there for, have long since retired and died; and the people who are there now are infused with "the storied history of GM" "we've always done it that way it's worked fine for 50 (or 70 or 100) years why should we change now" "are you telling us we've been doing it wrong all these years" "that's just Our Way of how we do it here" and other such mumbo-jumbo so they're too timid to strike out on their own and review REAL-WORLD data and step up to the plate and make a decision. Very typical of GM engineering in general.

If you really want to set them up RIGHT, which I highly recommend, you need one of these, or similar http://www.summitracing.com/parts/hrs-92156/overview/; for stock, or stock replacement springs, you want the height to be 1.70".

Use these valve guide seals. http://www.summitracing.com/parts/fel-ss72861/overview/

Roughly, you will need .125" of shim under the exh valve springs, and .030" under the int ones. It may vary a good bit either way but those are good approximate starting-out guesstimate guesses. Get a set of these http://www.summitracing.com/parts/cca-4754/overview/ and one of these http://www.summitracing.com/parts/cca-4751-16/overview/, should get you close enough.

I'd also strongly recommend putting on new valve springs; just, basic good-quality stock-ish replacements, such as these http://www.summitracing.com/parts/cca-981-16 along with their retainers http://www.summitracing.com/parts/cca-742-16/overview/ and keepers (locks) http://www.summitracing.com/parts/cca-601-16/overview/

Assembly is: valve into the guide, after de-burring the keeper grooves with 400-grit sandpaper so they don't ruin the seals; protector tool onto the valve; seal over the valve and onto the guide; protector off; shims onto the head; spring onto the shims; retainer onto the spring; valve spring compressor onto retainer, and operate it until the spring is fully compressed; O-ring into the bottom groove (optional); keepers into the top groove; release the spring compressor. Use 2-stroke oil as assembly lube on the valve stems, guides, and seals.

As said, valve spring height should be 1.70". That is the MINIMUM height. You can accept up to about 1.75" on those springs; shoot for getting all of them about the same, or at least, intakes the same and exhausts the same, and as close to 1.70" as possible on the high side. For example you might find it easiest to set all the int to 1.720 - 1.725", and all the exh to 1.735" - 1.74", with the shims you'll have on hand; that's fine. If you can't get em into that range, buy more shims in the thicknesses you'll need.

 

I also adjusted my valves this way. It's a brand new engine that hasn't ran yet. When the engine is running and the hydraulic lifters are "pumped" with oil, is this going to throw off the valve adjustment?

 

Are you saying, you did it the way I described; or, the way the OP described?

 

They way you described.

 

Well then, as long as you correctly identified "zero lash", it should be fine... all your errors, if any, will be to the loose side. Might be noisy, but won't interfere with being able to run. Easy enough to fix once it's running, if necessary.

 

Thanks for the help, sofakingdom. I think I may accumulate the parts and replace things as you recommended, when I get a chance (really need the car working for now, and the car work put me way behind on other work). I think the pushrod-lash 180-degree method will probably get me going for now, and I think I'll do a running adjustment tomorrow after I make some oil splash barriers -- that's the way we did it way back when.

 

Oh...in answer to the question, by "bearing" I was referring to the spring bearing assembly that makes up the stock exhaust spring retainer; the spring acts as a bearing and facilitates rotation.

 

I wrote earlier in the thread that I was planning to go back and replace my valve springs ('88 305 TBI) when I had time and could gather the parts.

A couple of questions related to that:

1) I bought the Howard Cams spring height micrometer linked earlier in the thread, along with new springs, retainers, and locks (also linked). The retainers do not sit down into this micrometer but are close enough to fitting into the micrometer that I'm a little concerned that the retainers sit significantly differently than they would if they sat completely on the face of the micrometer. The retainers tend to rock a bit instead of sitting firmly in place. Earlier in the thread sofakingdom said this about spring height: "As said, valve spring height should be 1.70". That is the MINIMUM height. You can accept up to about 1.75" on those springs; shoot for getting all of them about the same, or at least, intakes the same and exhausts the same, and as close to 1.70" as possible on the high side. For example you might find it easiest to set all the int to 1.720 - 1.725", and all the exh to 1.735" - 1.74", with the shims you'll have on hand; that's fine. If you can't get em into that range, buy more shims in the thicknesses you'll need. " There are two issues in my mind: a) whether the way the retainers seat on the micrometer face will throw measurements off enough to worry about; and b) whether the height settings sofakingdom mentioned represent the spring height alone, or perhaps the spring height plus retainer. Additionaly I will have to in any case measure the Howard Cams tool to see which surfaces the micrometer scale refers to -- it seems possible that the tool's designer contemplates that the retainer would sit inside the tool, which it does not -- it appears on the face of things that the tool may be intended to swallow the retainer, which it does not except perhaps slightly.

2) Second issue -- I also bought the seal kit linked earlier in the thread. There are two subissues:

a) The seals in the kit all look alike, while the old intake and exhaust seals look different from one another, there being an additional piece with one flat and one round metal retaining rings on the intakes which, once removed, reveals a seal that looks like the ones on the exhaust. The seal kit does not have any of the additional parts for the intake valves. Is, then, the idea to remove the additional parts on the intake valves temporarily, putting the old ones back in place after replacing the seals that came in the kit in place of the old seals?

b) I do not remember needing a special tool to remove the seals in the long-distant past -- is one needed, or is it ok to brute-force them off with pliers? I also have no special seal installation tool although i see two apparently identical pieces of plastic in with the seal kit -- perhap these are used to protect the seal during installation? Or would I need to buy something else to protect the seals during installation? Finally, the seals in the kit do not look quite like those on the older engine, having something circumferential near the upward opening that looks like a spring, perhaps designed to retain those additional items for the intake valves?

Many thanks -- I'll need to put this together tomorrow regardless. It's currently 9:00
pm Pacific time.

 

OK...worked on the car today and got stuck because the shims linked in a post above are the wrong outer and inner diameter for a 305 '88 TBI and can't be used. SO BEWARE OF THOSE SHIM LINKS! I'm stranded at the moment but with some luck my handyman will show up in the morning and give me a ride to the auto parts store so I can get some shims. I might get a couple of hours in on the car but it won't be done for tomorrow's needs so hopefully I can get him to drive me around to the other places I have to be tomorrow. I've had no reply about the seal replacement and it's starting to get a bit dark out, so maybe I'll try more on the web for seal-replacement instructions and do that tomorrow and the next day. I doubt I'll be able to finish tomorrow. Because of that delay I'm still requesting comments about my seal questions. One other thing to be careful about -- with this car and the spring height micrometer linked above, things are more difficult than they probably need to be. Because that micrometer is not slimmer, it will not sit down into the spring seats when it is fully collapsed. This makes installing and removing the locks a lot more difficult than it probably should be but it works with a bunch of extra effort. You also have to be careful that the micrometer has finally slipped all the way into the spring seat before you take your measurement -- it's easy for it to hang up outside the seat and give a false reading that's not far enough off to catch your attention. Also, there is the issue of the hole in the top of the micrometer being slightly too large for ideal use with these retainers. I'd suggest, for this car only, looking into a different spring height micrometer. Oh, a review... I bought a spring compressor at Summit, SUM906784. This is the type with a lever which drives a linkage to push down a pawl which bears on the spring retainers. It worked very well, and is a lot better in a tight engine compartment than the two dogleg boxend wrench method my Dad and I invented when we were stranded somewhere around Hermosillo Mexico in the sixties -- you can get away with that method better in a '63 Chevy 1 1/2 ton truck than in a tight Camaro engine compartment. Nonetheless, I had to remove the wiper motor to use it on cylinder #77. If you ever get stuck in Mexico, though, it might save you -- you put two dogleg boxends on one of the bolts, then the nut, then form a V-shape with them that can allow you to push effectively on a valve spring retainer. Long boxends are way better for this than short ones, and I know that ones in the vicinity of 1/2" to 5/8" will work. Anyway, the one I bought is quite nice and looks durable -- I broke two of the clamp-on type while disassembling (each on the first spring) and had to resort to the boxend wrench method.

 

This is an update on the spring compressor that I bought from Summit -- I previously said that I liked it. Actually, it worked fine for REMOVING locks, but when I put them back on with the new springs, this tool has a problem. The angle of the pawl (or foot...the part which surrounds the valve stem and applies pressure to the retainer, thus compressing the spring), is the wrong angle for my 305. I had to hold plastic angled shims in place on both sides of the valve stem, between the pawl and the retainer, so that the tool did not **** the spring and retainer at an angle to the valve stem which would not allow the locks to go into place. This was a very makeshift solution and a lot of trouble but I did not want to spend the time to make a more permanent solution today. I was unable to bend the angle far enough on the pawl with a hammer, and I don't have a large vise that's mounted at hte moment. I think it would work to make a metal wedge-shaped shim in the shape of the pawl, made such that it would either slip or screw onto the pawl. Without any wedges like the plastic I used, the angle of the pawl is too steep, so when you compress the spring, it ***** towards the upward side, away from the headers, and then you can't put the locks in place. I'd seriously suggest buying some other tool if you don't mind making something to modify the pawl to the correct angle. Otherwise, you might be able to bend the pawl in a large vise, or with a hydraulic press.