[steve25]

I take issue with that statement that Pontiac used positive seals on the intake guides of all 67 and up 4 bbl base line motors because I have never seen such.

I have disassembled at least 80 stock heads in my life between working at a machine shop and my own motors and I have never seen such and also not to mention that the Pontiac parts break down drawing don’t show any either!

The parts break down’s only show the valve stem o-ring oil seal as in this photo here.

Note item number 10.

[Kenth]

Originally Posted by steve25

I take issue with that statement that Pontiac used positive seals on the intake guides of all 67 and up 4 bbl base line motors because I have never seen such.

I have disassembled at least 80 stock heads in my life between working at a machine shop and my own motors and I have never seen such and also not to mention that the Pontiac parts break down drawing don’t show any either!

The parts break down’s only show the valve stem o-ring oil seal as in this photo here.

Note item number 10.

I wrote "high performance 4-barrel engines" NOT "4 bbl base line motors".
There is a difference.
And, your Pontiac illustration catalog picture shows an exhaust valve, exhaust valves did NOT use positive seals as i stated.
Also, take a look in the Parts&Accesories catalog group 0.308 and you´ll find #9790818 (positive) 8 seal, intake valve stem oil (w/retainer rings) for 1962-74 All engines. (As required for engines using them, of course!).

FWIW

[TRADERMIKE 2012]

Originally Posted by Kenth

I wrote "high performance 4-barrel engines" NOT "4 bbl base line motors".
There is a difference.
And, your Pontiac illustration catalog picture shows an exhaust valve, exhaust valves did NOT use positive seals as I stated.
Also, take a look in the Parts & Accessories catalog group 0.308 and you´ll find #9790818 (positive) 8 seal, intake valve stem oil (w/retainer rings) for 1962-74 All engines. (As required for engines using them, of course!).

FWIW

My 1967 428 ci HO YK code means Automatic/4bbl, I fit in that category? When we installed the 041 Cam, Johnson Lifters and HD Chrome moly Pushrods and new Oil pump and pan and Oil splash shields under the Valve covers, we noticed that the gasket set that came with this second-hand project included the
Valve seals in the opened box. So, we elected to use them, not being sure if we should or not, I guessed where to install them by seeing how they could only fit. Since the Exhaust Bosses were all cut to fit the Black metal band ones, positive seal I think there called, they got them. The Umbrella seals fit over the Intake Valve Bosses, therefore they landed on top, where the shoe fits, so to say.

Note: The mechanic mentioned that he is installing "o"-rings for the valve stems and he is milling the 8 remaining un-cut Bosses for the same positive seals as the Exhaust contain. This way they can't be carried off the Boss by the Intake Valve stems. Also, since my roommate performed the removal of the Springs, using compressed air into each Cylinder outside and out of my view, installing the new Valve stem guides, only he remembers what type of old seals that he removed, I can't ask him at this late hour.

[TRADERMIKE 2012]

Originally Posted by Jay S

It was a good catch by Kenneth to see it had one piston turned opposite the others. Pretty obvious mistake made by someone. Hopefully you get all the issues with the engine sorted out. That probably wasn’t causing any problems as long as the connecting rod was oriented right, but it needs to be fixed while you have it apart. Make them all the same, either stock, or reversed.

Having the pistons reverse hanging puts less force on the trust wall of the cylinder and piston skirt. It is really not much of a secret speed modification, and most of the time it does not do anything. Put all the pistons back stock, or leave them backwards, but get them all the same.

Sounds like the machinist is Knurling the guides. It tightens the guide up. It is not close to as good as bronze guides, but is cheap to do when the guides are a little loose.

Changing to Rhoad’s lifter would mean breaking in another set of lifters on an already used cam, which seems unnecessary since you have already run it. You probably wouldn’t like the noise Rhoad's lifters make anyway. Advance the cam to 109, fix the other engine issues and get it back together.

The cams overlap creating a ghost's noise is very unlikely.

Having the pistons reverse hanging puts less force on the trust wall of the cylinder and piston skirt. It is really not much of a secret speed modification, and most of the time it does not do anything. Put all the pistons back stock, or leave them backwards, but get them all the same.

You said: Having the pistons reverse hung puts less force on the trust wall of the cylinder and piston skirt. It is really not much of a secret speed modification, and most of the time it does not do anything. Put all the pistons back stock, or leave them backwards, but get them all the same.


Mikes reply: I am under the impression that the load on the original factory orientated Piston, with the offset pin that takes the thrust off the outside Piston wall and puts it up toward the inside wall, was genius and a credit to the engineers at Pontiac.

So, if one turns just the Piston 180 degrees on the same Rod factory orientation, defeating the purpose at the very least and causing more undue friction and more wear back onto the Piston outside wall. What was gained in the mind of the racers that performed this trick? What is gained and how do they get a couple of tenths gained in a quarter mile race? Some say it helped on some motors and some say not on others. Unless Blueprinting and Balancing is performed at the same time and who's to say that is the reason for the better performance. Testing on the same Engine both ways is the only way to tell, perhaps they thought of that? Makes me wonder...

[PAUL K]

The factory offset the wrist pin to make the engine run more quiet, it prevents noise from piston slap. Power can be found by installing the pistons so the offset is on the opposite side, now the piston will make more noise but will descend down the bore easier. If you install a piston with positive offset, bring it to TDC and push down on the piston top the crank will spin counterclockwise. If you do the same with a piston that has negative offset the crank will turn clockwise. If you do the same with a piston that has no offset the crank won't turn at all. Not sure how to rate this as to "how big" of a speed secret it is. I guess it's like most secrets. Once you know a secret they are either too good to keep, or not worth keeping.... I'm guessing most folks reading this thread weren't aware of why the factory pistons are offset or if they had any offset at all. But at the end of the day, as mentioned previously the most likely reason one piston was installed opposite of the other seven is human error.

[Jay S]

Read Paul’s comment and picture how that wrong piston is operating relative to the other 7. It is pushing down on the crank crank at top dead center a couple degrees different than the other 7 pistons. That is throwing off the balance of the engine some because the mass of the piston has a different dwell at top dead center than the other 7. There would be no way I can think of that any engine could be balanced properly like that.

In addition to the balance, running the piston offset backwards from stock, it also changes the timing the engine wants also by a few degrees. I want to say it takes less timing by a couple degrees.

It can (and did) run like that, but it is certainly not right.

[Stan Weiss]

Originally Posted by PAUL K

The factory offset the wrist pin to make the engine run more quiet, it prevents noise from piston slap. Power can be found by installing the pistons so the offset is on the opposite side, now the piston will make more noise but will descend down the bore easier. If you install a piston with positive offset, bring it to TDC and push down on the piston top the crank will spin counterclockwise. If you do the same with a piston that has negative offset the crank will turn clockwise. If you do the same with a piston that has no offset the crank won't turn at all. Not sure how to rate this as to "how big" of a speed secret it is. I guess it's like most secrets. Once you know a secret they are either too good to keep, or not worth keeping.... I'm guessing most folks reading this thread weren't aware of why the factory pistons are offset or if they had any offset at all. But at the end of the day, as mentioned previously the most likely reason one piston was installed opposite of the other seven is human error.

When there is no pin offset the piston and the rod journal are ATDC together. Depending on the direction of the pin offset the piston will either be before or after its TDC when the rod journal is ATDC.

Stan

[PAUL K]

Originally Posted by Stan Weiss

When there is no pin offset the piston and the rod journal are ATDC together. Depending on the direction of the pin offset the piston will either be before or after its TDC when the rod journal is ATDC.

Stan

Hi Stan, that's probably a better way of saying it, technically

[Cliff R]

The only thing we can conclude from the information provided thru far is that someone made a "mistake" during the assembly of this engine.

Highly UNLIKELY that 7 out of 8 pistons were installed in the wrong direction on purpose, as mentioned above.

They ALL need to go back in the correct direction and the rods put in so the "flats" face each other anch chamfered ends out toward the radius on the throws.

Unless I missed it someplace I'm the only one with 100,000 miles of DIRECT experience having inadvertantly installed the pistons in the wrong direction for 10,000 miles, then taking the engine back down and putting them in the right direction for another 90,000 miles. It isn't an option, the engine will never be up to par with 7 in the wrong way and one in the right way. One should ALWAYS spend the time/funds, no matter how costly at the time, to do the best they can with these things. Otherwise you end up on these Forums trying to get others to solve issues that you could have easily avoided. Most likely here noise from the pistons slapping all around in the bores and oil consumption or poor ring seating from the rings getting dragged all around in the bores on those flopping around pistons.

At this point we're up to 13 pages and 7 pistons are still in backwards and worn valve guides have been knurled instead of the heads getting a full set of new guides with new once piece stainless valves in them.

Personally I'd rather start an engine out with new components, better components, and on the minimum spec. If nothing else I'll sleep better at night knowing I'm not going to have to go back in it anytime soon.........FWIW.....

[TRADERMIKE 2012]

We just found a smoking gun this weekend. As we were experimenting with the degree wheel, I noticed that the Inner Harmonic Balancer had a crack along the Keyway groove outside the Hub running along the entire height of the Hub, bad news but problem located. The Harmonic Balancer Dampener is there for eliminating torsional Crankshaft vibrations and this word that starts with a "V' has been the very reason for pulling the Heads. A positive blessing in disguise I would say.

The Cam and Valve open and closing events occurred as the manufactures Cam card dictates, they should, given that we took our readings while "not" knowing about the aforementioned Crack. Since I had no Cam card, we simply made our own using the information at our disposal from the internet. We read a lot and learned more. We are at TDC @ 113.5 advanced by a factory built in, one and a half degrees, this is calculated with the Cam installed with the Intake and Exhaust Valves closed on the Compression cycle on number one Cylinder and the Base Circle facing up. We point the Cam and Crank dots at 12 o'clock high plus there was no advance added into the straight-up installation, except for the 1-1/2 degrees the factory added in prior to my purchase. Since we want to be as close to 109 C/L as we can get, we moved the Crank Gear advanced by four notches. Each notch at the Crank is two degrees adding up to (eight degrees total) at the Crank, that is equal to (four degrees) at the Cam. We figure that (113.5 Intake C/L) minus (four degrees) at the Cam, equals (109.5) advanced Cam, now race ready Installed and at High Performance specs.

I am contemplating, that when I had an accident two years ago, causing my TH 400 Trans. to be lifted up at the Trans. oil pan. Then creating irreputable damage to both the Torque Converter and Pump. The blunt trauma, lifting while thrusting forward causing damage to the Forward Drum Seals that broke the metal clasp type
Oil "O" - rings, between the forward Hub/Drum and rear of the pump, meaning a significant loss of oil "not" getting to the forward Clutches, then starving the rest of the Trans. Oiling system, all the way down the line. Again, I think that The Thrust from that nightmare carried through to the Harmonic Balancers Hub, causing the current Crack in the hub today that is making the Ghost noise/vibration? The Harmonic Balancers Dampener
with Hub is for eliminating Torsional Crankshaft vibrations on this internalized Balanced Crank counter weights. Note: a simple Crack opening and closing at 1500 rpm, 2000 rpm, 3000 rpm and then 4000 - 5000 rpm is what must be the problem. If I am correct, I don't have to rebuild the bottom end just yet, keeping my fingers crossed.

I found a used Hub for my Harmonic Balancer today, delivered for $44.35 and I learned of a speedy sleeve, that mounts over the Hub some .009" that will cover and adhere to the Hubs outer surface. This speedy sleeve sits over the Hub slightly worn area. I plan on carefully treating the Hubs outer surface, with tender loving care, using light sanding emery cloth and then buffing it with three different cloth type buffing wheels, rotating on my grinding wheel motor. Then I can apply three types of buffing compounds, just like I did on the TH 400 Trans. Foward drum and Hub, reaction carrier Drum. The timing cover seal created a noticeable mark, etched into the external Hubs surface and will be freshened up to the best of my ability.

An aftermarket Hub, that is new, costs about $200 delivered and functions like the originals. My question is: "do I really have to spend four times the used price for the new aftermarket China Hub or should I just sleeve the used original, American made Hub for an additional $10 myself"? Only the used Hub was affected in this case, not the Harmonic Balancer or four Pullys nor the inner ring or hardware.

Question 2) If I can even find a Dampener that will work with my existing parts less my Hub, even if I buy the $44.35 Hub, I would like to have a degreed Dampener with the lines and numbers etched into it all 360 degrees around the circumference. How nice would an Aluminum Dampener and Hub be for the unstrung weight? Would the Vehicle charge off the line, certainly making a noticeable difference. My pocket has moths coming out, but my love for improvements captures my interest.

[Cliff R]

Harmonic balancers outer rings slipped or cracked at the keyway isn't all that uncommon.

I would NEVER for any reason buy a used one, the rubber between the hub and outer ring is at least 50 years old at this point and harder than the counter tops in my kitchen, plus cracked and loosing all it's memory to keep the outer ring in place.

Pioneer replacment balancers are excellent, the SFI version even better. The stock replacement DA-4551 are in the $60-80 range. At a minium go that direction vs buying a used one that needs a sleeve over it and probably ready to throw the outer ring off it anyhow.......

[Jay S]

Post a picture of the timing marks on the timing set with #1 cylinder at TDC. The way I read the cam timing post is you have a multi key double roller timing set, and have the cam timing advanced 8* from stock, and did not check it with a degree wheel.

X2 on Cliff’s comments.

[400 Lemans]

Starting from 113.5. In order to read 109.5 at the degree wheel you need to move crank gear 4 degrees not eight.

[Formulajones]

Originally Posted by TRADERMIKE 2012

The Cam and Valve open and closing events occurred as the manufactures Cam card dictates, they should, given that we took our readings while "not" knowing about the aforementioned Crack. Since I had no Cam card, we simply made our own using the information at our disposal from the internet. We read a lot and learned more. We are at TDC @ 113.5 advanced by a factory built in, one and a half degrees, this is calculated with the Cam installed with the Intake and Exhaust Valves closed on the Compression cycle on number one Cylinder and the Base Circle facing up. We point the Cam and Crank dots at 12 o'clock high plus there was no advance added into the straight-up installation, except for the 1-1/2 degrees the factory added in prior to my purchase. Since we want to be as close to 109 C/L as we can get, we moved the Crank Gear advanced by four notches. Each notch at the Crank is two degrees adding up to (eight degrees total) at the Crank, that is equal to (four degrees) at the Cam. We figure that (113.5 Intake C/L) minus (four degrees) at the Cam, equals (109.5) advanced Cam, now race ready Installed and at High Performance specs.

Maybe I'm missing something in your description but there is no mention of using a dial indicator on the cam. There is no way to know exactly where the ICL is without having a dial indicator on the intake lobe. A degree wheel by itself won't cut it.

[Jay S]

Doesn’t appear there is mention of a degree wheel either?

If your assuming factory settings are correct, the factory intake center line of that cam is suppose to be 112* when installed dot to dot.

The lobe separation between the intake lobe and exhaust lobe is what is 113.5*.

[Cliff R]

"we moved the Crank Gear advanced by four notches. Each notch at the Crank is two degrees adding up to (eight degrees total) at the Crank"


FWIW I read the paragraph about where the cam is at couple of times and could make no sense out of it whatsoever. I've been at this engine building this coming up on half a Century and couldn't get a grip on it and I don't have or have never had any cam gears with "notches" on them. About the only timing sets I could move without offset keys were the 9 keyway sets and each movement of the crank gear REQUIRES the installer to use a NEW reference point or "dot" to line up with the "dot" the cam gear. Early Rollmaster sets were not well marked and the instructions sent with then as useless as the toilette paper you doddled last time you sat on the crapper.

I've seen very experienced engine builders screw that pooch up pretty good when using Rollmaster timing sets when they deviated from "dot to dot" and started using the advance or retard keyways.........FWIW.....

[TRADERMIKE 2012]

When we removed the Heads, we found that the Exhaust Valves, at the center of each Head, where the two Exhausts Valves are adjacent to one another, were sunk /recessed into their un- hardened factory Seats by about 1/32", possibly adding 1/16". The O/A Valve slap/noise, in an overly heated area. Duly noted, we removed the Heads, to be machined with new hardened Exhaust seats. After learning both about the Pontiac Block and 421 Head cooling mods., over this PY forum, it is just as well that I drill the Heads between the two center Exhaust cooling ports, for better cooling in that area, that is, when I get them back.

Of course, we have already drilled and plugged three holes on each Deck that the Head rests on plus, tapped and plugged them, with stainless plugs. We also drilled the 421-mod. holes between the center Exhausts ports into the Block, on both Head Decks. Thís should help in "not" allowing this overheated area from ever getting that hot.

We used a Dial indicator over the Piston and Degree wheel to find the TDC, using a stop, that we made from flat aluminum added 2 Bolt holes to lock it down to the Deck. By drilling a smaller hole in the center of the flat stock, we tapped a bolt through that hole, to measure depth along with a feeler gauge, over cylinder # 1 using the intake Valve on the compression stroke.

To find the actual ICL, we placed the Dial indicator over the edge of the Intake Valves Hydraulic Lifter and measured the duration of the Cam @ .050" on both sides of the Valve duration Ramps by passing the .050" mark on the Dial Indicator first then moving toward the .100" mark first then rotating back to exactly 050", where we took our readings off the Degree wheel # and recorded that number, adding those numbers and dividing by two equals 112 degrees for the Intake c/l and 115 degrees for the Exhaust c/l, then to obtain the lobe separation angle we added these two numbers and divided by two equals 113.5 degrees.

We advanced the Valve Timing from 113.5 to 109.5 by using the Comp Cam four-way Crank Gear, each notch is two degrees according to their directions, thus the fourth notch equals 8 degrees at the Crank and that means 4 degrees at the Cam. Because the Crank rotates twice, 720 degrees and the Cam rotates once 360 degrees. 360 degrees at the Crank equals 180 degrees on the cam, the Crank spins 2x the Cams one. Half a turn at the Cam is equal to one rotation of the Crank.

We were told by Butler Performance that Melling added 1.5 degrees to my "041" Cam and that I should install the Cam straight - up, in the Pontiac case, that is orientate the dot mark at 12 o'clock on both the Cam and Crank gears @ TDC on the compression stroke.

On my 1979 Pontiac T/A we point the Rotor within the Distributor cap toward #1 in the firing order, toward my steering wheel, where my timing order starts and rotates CCW within the Dist.

Because there is little room remaining between the 428 ci Engine and the Fire wall, under the windshield and the MSD large Distributor Cap, we orientate the Vacuum Advance canister vacuum port toward my Steering Wheel.

Currently the Rotor is pointing @ number 6 in the firing order within the Dist. Cap and we are on TDC on number one Piston cylinder, because #1 and #6 are companion cylinders plus one must consider the constant changing Valve opening and closing events.

We spent a lot of time proving that the Valve opening and closing events were happening at both 050" and .006", according to our self-made Timing card numbers that we made from information obtained over the Internet and the Melling Cam site. These numbers were exact.

The Intake and Exhaust Cam lift is .313" each measured off their respective Lifters.

The Lobe separation angle (LSA) is 113.5 degrees as well. Intake c/l is 112 and Exhaust c/l is 115 for the "041" Melling Cam and we are using 1.5 Rocker arms. Total lift is .469" on each Valve and the Cam is asymmetrical in Pontiac design as all their Cams were in the day or so I read. You take 115 - 112 = 3 divided by 2 = 1.5 degrees. I believe this is how Butler Performance had Melling build advance into my Cam by adding Intake 112 c/l to 1.5 obtained above = 113.5 LSA = new Intake c/l advanced, this is done to asymmetrical Cams.

I installed the "041" Cam straight-up initially for degreeing purposes, plus to find TDC. Then I went back into the Timing cover to advance the Cam Timing by 4 degrees, for a total of 109.5 race ready performance purposes.

The Cracked Hub is the "Vibration smoking gun", issue along with the 2 Exhaust Valves slapping away in their worn-out Exhaust seats, I am sure of that, this is my Theory and add in the fact that the Exhaust cross over plugs were not doing their jobs. is like adding the candle on top of the cake so to speak. Now through in the Valve guides only needing remanufacturing back to factory spec. no more no less, they still contributed to excessive Vibrations. Of all the emphasis put on the Pistons, I disagree to agree it matters. But it is not my problem, it is yours who experienced it firsthand. I have a lot of **** to fix and I don't want to fix anything that is not broken at this very moment. I learned much in this discussion and found out even more as I disassembled the Engine. In conclusion, I will not have to rebuild the bottom end today, I am saving for a rainy day when there is nothing else to do.

As far as the Hub is concerned, I am glad that I asked the question whether or not to buy a used or new one. Here is my related story, once on my 1981 Camaro Z-28 I changed the Harmonic Balancer only to have the Timing Gears and Chain fail one year later, causing me to sell it, as is. The fact is I loved that red luxury interior, that it possessed. Not to mention that it had T-tops, plus factory air induction, electric windows, tilt steering, rally gauges, add on AC with automatic Trans. with a center console, air induction that actually opens and closes when I smash the peddle down to the floor. So, what I am leading to is: "This is where I want to spend my money, at this time that makes a big difference, let's talk about spending Mikes money on a Hub or complete Dampener that will be strong, one that will save this poor tired Engine, so I can squeeze the existing life/miles out of the Crank and Pistons and rings that are waiting to be driven yet.

[TRADERMIKE 2012]

Originally Posted by Cliff R

"we moved the Crank Gear advanced by four notches. Each notch at the Crank is two degrees adding up to (eight degrees total) at the Crank"


FWIW I read the paragraph about where the cam is at couple of times and could make no sense out of it whatsoever. I've been at this engine building this coming up on half a Century and couldn't get a grip on it and I don't have or have never had any cam gears with "notches" on them. About the only timing sets I could move without offset keys were the 9 keyway sets and each movement of the crank gear REQUIRES the installer to use a NEW reference point or "dot" to line up with the "dot" the cam gear. Early Rollmaster sets were not well marked and the instructions sent with them as useless as the toilet paper you doddled last time you sat on the crapper.

I've seen very experienced engine builders screw that pooch up pretty good when using Rollmaster timing sets when they deviated from "dot to dot" and started using the advance or retard keyways.........FWIW.....

Then it is a good thing that today comp cams has taken the thinking out of performing this important procedure. The instructions are online in the various forum groups, as well as in the box the Gears come in, FWIW MIKE out.

P.S. The miss-leading information out there is plentiful and sometimes confusing, often times unreliable. I choose to ask lots of questions, so ultimately, I came to the correct conclusion, "not" better than anyone, just more informed before dedicating my assets to the fix.

Also, my 1967 428 ci HO YK code Harmonic Balancer is different than most and the last year for it. First there is no rubber used that year (1967) and the Hub is made of solid Cast Iron and bolts to the Balancer, that also is an Iron weight with a stamped steel that is joined in some pressed manufactured method, that you need to be an engineer in order to understand the processed method. Then the two stamped pulleys are three Belts in one and one separate pully for the AC, if you need it. Then there is a plate with holes in it with various bolts that will assemble the amalgamation of parts together. Only the center Hub is damaged on mine. This very important part needs to be replaced with a quality unit. I want one that works with the existing pully system so I can retain Pontiac factory look, everything in my Engine compartment has the 1967 appearance and I want to maintain that look. However, I must insist that there be 360-degree lines and marks for Timing the Engine. Steel/Iron Billet is good, But I am wondering if I should go for Billet Aluminum to lighten the unsprang weight on the reciprocating parts like the Crank, rods, Pistons and Wrist pins. I am willing to spend between $300-$400 for the best. After studying my broken Hub and seeing the Crack along the existing keyway. one can only surmise this happening on another 50 year old part. I agree with your statement about purchasing another ancient used Pontiac Hub.

[Kenth]

https://www.amesperf.com/parts/13651/

With all the talk about doing this and that with blocks and heads and god knows what, you're going to continue to build the engine with 7 pistons backwards?

[Jay S]

Every 9 way timing set from comp I have ever seen is designed so each key effects the cam timing by 2*.

-8*, -6*, -4*, -2*, 0*, 2*, 4*, 6*, 8*

I hope the cam was degreed in after the cam timing was changed. The 9 way timing sets are designed to changed the cam timing in 2* increments, irregardless of the crank turning twice as fast as the cam.

Sometimes harmonic balancers fail because something on the inside of the engine create’s an unusual stress on it. Could be having one piston in backwards contributed to the cracked hub.