Engine is big block in E Body with aluminum heads, angle spark plugs, TTI 2 inch headers.

Have been removing and pressure testing at close and full open all valve springs plus measuring coil bind, .060 fudge factor before coil bind after full open,,,,,etc, using a bench valve spring compressor and a Comp Cams install height micrometer.

Have used air pressure, rope trick and top center for ensuring that I do not drop a valve into the abyss of a cylinder,,,could be a bad day at blackrock.

Going well, albeit a bit slow and tedious. Have already found issues that I will report on later. Enough to say for now is that I have found 2 different valve springs that had less than minimum .060 between full open and coil bind,,,one of .054 and one if memory serves(I have all numbers written down) of .050. Have corrected with Porter recommendation of .050 keeper to increase spring install height. There remains some very vexing questions for which I do not have answers however.


I am at number 6 cylinder and no access to attach air to spark plug hole, rope is very difficult,,,,and do not fully trust it. Therefore best option is to ensure piston is as close to top center as possible,,,,which incidentally i have come to prefer as my favorite technique to ensure success and not drop a valve into cylinder.

My question is this, what is the best method of ensuring the piston is at its top in the cylinder.

Can I rely that the exhaust valve is fully open? Can I rely on both valves fully closed? Both by observation of lifter position in bore. Rocker assembly of course is removed.

Is not either of these, any other suggestions,,,,I have already tried placing a screwdriver or a sods straw or tie wrap in the spark plug hole. Cylinders 2, 4, and 6 are just too tight and I am working alone, turning over engine with a socket on crank pulley from beneath the csr and keeping track of these devices is above my pay grade.

I am aware that when one piston is at too center,,,another one also is. Does anyone have a chart on this that shows the companions that are at top simultaneously? Some recently posted this, I have lost track of it

Only 12 valves left to go. By the way, the 4 so far pressure tested springs measure almost as new,,,both at initial spring install height and at full open,,,,as per Comp Cams factory specifications.

Oops, just found this very useful post.


Still have original question however, ideas on how to determine any given piston is at top of travel,,,,making no difference if on compression or exhaust stroke,,,just by observing lifter positions in their bores.



perfmachst Offline
member

Registered: 09/02/10
Posts: 156
Loc: renton , washington
hi, run # 1 piston to tdc. you can remove springs on # 1 and # 6 same time . with out air pressure or rope. after installing said springs, rotate to # 8 , it and #5 are at tdc, change them both. the valves will drop down some onto piston tops. I change my springs, this way. #1& #6, # 8&#5, #4&#7, #3&#2. follow the firing order. can't miss. there is always two pistons at top same time. one is on firing tdc, other is on overlap.

Whichever one you are working on, the one that's 180* off on the distributor cap is also at tdc.

Just split the firing order:

1-8-4-3
6-5-7-2

I thought those springs were likely still okay...... They're pretty durable.
That's why I suggested using a good bench top tester to compare to the on head tester.

What was the spring pressure, open and closed, of the springs at the heights they were installed at?

if you have confirmed the dampener slit on on true TDC for #1 or #6 you could back up the crank a few degrees then come forward till the slit is on TDC & see where the reluctor tooth clocking is at in relation to the magnet then hand bump the crank forward till the next tooth is in the same relative clocking to the magnet (dont go backwards cuz that introduces the chain/intergear slop. A person could also get a cyl as close to TDC as you can with a rod in the cyl then make a paint mark on the dampener at that point on zero on the timing tab then back up the dot to 15BTDC & screw in the TDC tool to firmly contact the piston then go CCW & see if it contacts at 15ATDC & if not exact then split the difference in the numbers to find exact TDC. Might need to start at 10BTDC so you have room to work (been a long time since I done it). EDIT if the cam is symmetrical you could as you mentioned get "rockover", the point where the lifters on overlap are both moving and are at the same height & that cyls' piston and its companion cyl should be at TDC but there is still the chain slop issue as you are going back & forth a bit to get the heights equal. Assuming you want dead on as opposed to very close. MORE EDIT (1) confirm TDC dampener slit is true. (2) cut a strip of white paper 5.694" with your calipers (3) use it as a ruler on the dampener and a sharpie marker to get to/mark each of the next cyls' TDC, to #8 then #4 etc. (4) Only need (3) ink marks along with the TDC slit.

If you bring # 1 cylinder up on TDC on the firing stroke on balancer( you can look at the distributor rotor also ) and timing cover marks and put air pressure in that cylinder and it stays at TDC so will #6
Most motors will have between 2 to 6 degrees from TDC that the piston will stay still there with air pressure, after that they will blow down under pressure

# 3 intake, one of failed lifters. Uncompressed spring. 2.45 inches All 4 springs that I have measured come in very close to this. 2.479, 2.485, etc. CC number 26120.

Seat load spec for beehive from CC is 155 pounds at 1.88 inch. I measure with desk top tester at 160 pounds.

Open load spec is 377 at 1.280 inches. I measure 372 pounds.

Coil bind spec is 1.230 inches.

My CC cam 23-713-9 intake lift is .549' exhaust lift is .544.

With these numbers one can readily calculate the slight possibility of very marginal coil bind if install height of this valve is only 1.835,,,which it was,,,instead of spec of 1.88. It apparently can occur just a few thousandths under the minimum requirement of .060 as recommended for street use. Perhaps a hundred thousandths for racing activities.

I have found this less than .060 error on 2 valves so far. Interestedly caused I suspect not because of erroneous install height measurements by the machinist who installed the springs. I suspect more an issue of close enough for government work.

I say this because it appears that valve spring seat shim appears to be less than 20 thousandths thick,,,so would be of little consequence if install height was from above the shim or above the head surface.

Additional evidence as outlined below.

Number 1 cylinder intake installed height came in at 1.85 inch, measured 150 pounds.

Therefore no corrective action with +.050 keeper required. So kept original so as not to lose seat or open spring pressure.

Right now fighting problems when compressing springs to remove keepers,,,they often do not wish to release. Been smacking with a brass hammer,,,hitting with a 11/16 socket,,,etc. compress valve down to where it hits piston. Still no go. The eventually let go. Any tips appreciated


More to come as I move thru all valves. Happily not paying someone an houly rate.

Number 1 and 6 I got with timing marker. It's the others I am seeking the best solution.

What is working now is to wrap a Phillips screwdriver with tape,,,,shove it in spark plug hole, turn engine by hand until will not go anymore, know I got that cylinder ok, then assume that its "companion" cylinder is good to go.

Not using any air as cannot get chuck on 2,4,6 so just let valve rest on piston. Then place a tight 'O' ring on valve after pulling it off piston to put keepers back on. Then 'fish' 'O' ring out with a dental pick. A little tedious but can get it. Does anyone know of any downside of leaving the 'O' ring on stem,,,,outside of possibility squosing it between retainer and retainer.

Use a cloth seamstress tape to measure the O.D. of your dampener and make marks at 90 degrees from TDC, if it is 7.25 diameter then 3.14 x 7.25 = 22.765 inches in circumference then divided by 4 = 5.69 inches from TDC to 90 degrees and then twice that amount to 180 and so on That will give you 90 degrees marks so you can turn the crankshaft one revolution and stop every 90 degrees to get eight pistons at TDC, don't forget that one cylinder will have the valves open on the overlap stroke when the other cylinder will have them close for the compression and firing stroke
Good luck, have fun

Generic spring shims come in .015, .030, .060 thicknesses........ So it's usually possible to get the installed height within +/- .0075 of the target.

Some of the higher end shims come in .020, and .050 as well......... But I don't come across those very often.



This assumes the RR is right at 1.50, which HS usually are not.
And until you measure the lift at the valve, with full spring pressure, using either a solid or bottomed out lifter...... You won't know for sure what the net RR is(or the net lift at the valve, or the true distance to coil bind).

At this point, you're assuming the lift is .549......... Just like you assumed the installed height was 1.88.

Understood. I recall your mentioning that HS's RR were closer to 1.55 ratio than normal 1.5. Also the spring seat shim used on these heads is almost paper thin, so likely .015 version. Did not remove to measure as did not wish to disturb valve seal. Did best I could using depth caliper.

This then would be significant if calculations to coil bind were close. Meaning that if a spring on a certain valve had passed the .060 safety margin based upon 1.5 ratio, it may fail and bind pif cacluated margin was at .060 based upon comp cams valve lift spec which is based upon a RR ratio of 1.5. Or in the case of where I had calculated .050 margin on a couple springs, perhaps I had let us say only a margin of ,040. Would have to do the math, but I get your point.

I do have an adjustable so called "test" solid lifter. Would it be recommended to test every cam lobe? That could prove formidable.

Perhaps simpler to merely replace all keepers with + ,050 version and lose a very modest amount of spring pressures and guarantee a significant safety margin. Even with stock keepers I collapsed only 3 known to this point(have not yet examined each of them) and that only after a couple thousand or so miles on them.

Very interestingly I did check number 6 exhaust today. This was the first collapse I experienced a couple of years ago, was unable to examine it as I had merely returned to Summit who had sent warranty replacement.

This valve using Comp Cams install height micrometer measure right at 1.80 inches. I had somewhat ran out of gas by this time so did not test spring etc. I plan to recheck install height on this valve again tomorrow.

As an aside, I had mentioned using a very tight fitting O ring to prevent valve from falling,,,in my case not too far as I have piston's very close to tdc. Also for keeping valve closed while installing spring and retainer. Had said that to remove this O ring when done, I had to snag it best I could with a dental pick and rip it out.

Occurred to me today to use 40 pound fishing line which I have in toolbox,,,a favorite go to tool,,,to loop around this O ring before placing ring on valve stem. Then once keepers are in place, merely pull this line hard enough to tear the O ring, or at least pull it out enough to snag easily with the dental pick and then tear it.

Still wonder if even must be removed.

With the tips on companion tdc piston sharing I got from Robert, Cab, Perfmachst and others,,,,I am now a firm believer that bringing piston to tdc is for me and my cautious paranoia the safest and effective way to remove valve springs with the head on engine. Pulling a head to retrieve a lost valve gives me nightmares thinking about it.

Thank you to all who have shared your extensive wisdom and experience in this quite convoluted journey. i hope it will help others down the road.

More to come.

You might back the piston up a bit then feed some 3/8" white nylon rope in the plug hole then bring it forward to keep from dropping a valve. A foot and a half is plenty/cheap & agreed you don't want to even think about what could happen!

I wouldn't put a flat faced lifter on the cam for the RR test.

If you squeeze the oil out of one of the hyd lifters, then adjust the rocker so the plunger in the lifter is "bottomed", that will give you an effectively "solid" lifter.

You're saying the only thing under the spring is a thin shim?

Nothing to locate/center the spring like a spring cup or inner spring seat?

If that's how they are, that's a situation I would address if it were me.

When you have a spring off...... Take a pic of what's under the spring.

The .015 shims often don't hold up well to a spring that's experiencing some unhappiness.

Adjustable "testing" solid roller.

I have examined each shim for damage as springs were removed. . I did note that they may have excessive space to "float" about in head's spring pocket.

Have not yet investigated how to remove and re-install oil control seals if I were to replace spring shims.

Robert:

I did use rope trick on one cylinder. Was able to shove 3 feet of 1/2 inch rope into spark plug hole And yet valve with spring remove would still slide down into guide to where keeper notch was at level of oil seal. I was very uneasy so rotated engine sufficient to force piston and rope further into cylinder to the point that valve could no longer drop at all,,,,which was good.

I thought I was watching some Houdini magic trick as that spark plug hole sucked up my whole 3 plus feet of that rope.

If the hardened steel spring cup(.060 thick) that came with the heads was removed and discarded, and replaced with nothing more than a shim, I have even less confidence that your heads were set up competently.

Actually, I guess it's apparent to me at this point that they weren't.

As I mentioned previously, with an assortment of 15/30/60-thou shims, you can get within +/- .0075 of the target installed height, and you've already found they are farther off than that, and now we discover there is no longer a hardened spring locator being used.

That is not quality work.

So, IMO, it's back to my original recommendation of using the +.050 locks on all springs, only now some hardened spring locators need to be re-installed.
The "correct" locator for those springs on those heads is # 4696-16, or you can reuse the ones that came on the heads if you got them back from the machine shop with your heads.

It now appears that machine shop that changed out Ede head springs for beehives was unable using ,060 spring seats to achieve Comp Cams and Ede recommended install spring heights using Ede supplied original keepers.

Therefore being unable to gain the distance required to achieve recommended 1.85 spring height, instead of using +.050 keepers, they elected to go to a much thinner spring seat,,,and still yet in at least a couple of valves, perhaps more to come, still unable to obtain minimum .060 clearance before coil bind possibility. As I noted in another posting, this was a small town shop which likely had little experience in performance engines and technology, although I say again his heart was in the right place for the customer. Valve trains as I have learned require much hands on wisdom and experience that most have yet to achieve. Even the techs at the major vendors appear to often get it wrong, many will agree.

Is this more or less your assessment and what started this cascade of events.


Would you offer your recommended method on how best to remove and replace valve oil control seals? Are they reusable once removed, or must they replaced with new?
Is their a favorite model or brand you recommend. I already have a complete set of Comp Cams shims,,,15, 30, and 60 thousandths.

Not certain if I am up to replacing all spring shims and valve oil seals right now unless you deem critical. Been dealing with a somewhat serious low back issue, in fact have a procedure scheduled for 7:15 am tomorrow.

I would go back in and do it correctly later.

Thank you

IMO, a "proper" hardened spring locator needs to be installed.
Again, either the cups that came on the heads as they were delivered by Edelbrock, or the Comp 4696-16.

Remove the retainer, spring, seal, and current shim.
Put the spring cup on the head, check installed height with +.050 locks.
If you need to reduce the installed height at that point, put any shims under the spring cup/seat.
Once the installed height is set, reinstall the seal, spring, retainer, locks.

I can't tell from the pic what are on the heads for seals. The heads come with
rubber "ring and band" seals. If they still have those, they can easily be worked up off the guide with a screwdriver, and then carefully slipped over the groove in the valve.
They can be reused, and will slip right back over the valve and guide.

As the heads are now, they are not properly set up.........so you can do it right.......or do it over/again.

"I" wouldn't run it like that.......but I'm not the one in charge of this job.

I can see by the "shadow" in the spring pocket that it appears the springs are moving around quite a bit.

Without testing the springs for myself, and seeing how the pressure starts to spike as the coils start stacking up, I can't say for sure if this is where the root of your failure lies.
However, I'm pretty confident it isn't helping matters any.

Much earlier on in this process you're going through, you should have verified what the actual net peak lift at the valve is. Then you'd have a better idea how close to coil bind the springs really were.

As I said in the previous thread, I feel the three contributors were, fast rate lobes, oil too thin, springs improperly set up.
Fixing how the heads are set up, and running different oil are relatively easy to fix.