[blown 68]

well, right before i took the engine out of the 68 for this rear main issue, http://tinyurl.com/33pne4 something started makin' a squealin', not the good kind, (like my tires), but like nothing i'd ever heard, luckily, i was only a few blocks from home, and it was rpm sensitive, so i rode it out, hoping whatever it was would make it there. (probably not the smartest thing to do, but hey, a calculated risk..)
sooooo, i pulled the engine, alternator checks out, water pump checks out, PS pump checks out, idler checks out, only thing left: blower. i took it down to my friend who built it, (he's been a bds rep for twenty plus years), we pulled the back cover, low and behold, a bad bearing on the drive rotor locked up a bit, just enough for that baby to start spinning in the bearing plate, (refer to 'makin' a squealin' above. ) which in turn wallowed that sucker out. could have been fixed, he showed me the repair, it's a metal collar, like a slice of pipe, they heat up, and press around the bearing boss to tighten up clearances on the bearing itself. then i saw a replacement back cover, with the fins on it, and decided, what the heck, go for the pretty one, and not worry about the repair on the old plate. this one has little removable covers over each bearing too, in case you want to check on them periodically.
anyway, just wanted to share, i always like looking at other peoples stuff, so, in the next month or two, i will share some pics of the car going back together, and some of my stuff. for now, here is my nifty blower backside, and the 'ol workbench, and mama waitin' for her new ticker...

[johnta1]

Glad you found the 'squeal'.

Maybe instead of when you replaced the rear cover, you should have replaced it all with a 8-71 ?

[blown 68]

Originally Posted by johnta1

Glad you found the 'squeal'.

Maybe instead of when you replaced the rear cover, you should have replaced it all with a 8-71 ?

well ya know, it crossed my mind. and then i was thinkin' about better heads, then i was thinkin' about an IA II block, then i was thinkin' about the new billet cranks, ah, you know the drill..................so, a new endplate it is.......for now.

[goquick]

Looks great! I'd say you made the right choice.

[360Rocket]

damn, hate to see my favorite car come up lame. Keep us updated as you know we love to watch build ups. Sorry that happened and good luck with the build.

[blown 68]

well, not exactly an update on the engine, but i was out in the shop tonight, taking some pics of brakelines for another thread here, and i thought, what the heck, how about some shots of the inside of the ride, so you can see my perspective while driving this monster..............oh, and an inside look down my offy blower manifold, in case anyone wondered what the plenum etc, looks like.

ps, the gauge cluster is the usual suspects, oil, temp, volts, and the little guy on the right is my a/f ratio gauge, by innovate, the 'all the works in the cable' model. (brain fart on model number....) and the ol' classic, a pontiac manifold vacuum gauge on the console, (yes i know it doesn't belong on this year, but neither does a 6-71. ) it is plumbed at the base of the carbs, on the carb adapter plate. i have a boost/vacuum gauge, plumbed to the intake, with a 'tattle tale' in one line, and a realtime line, plumbed with a three way valve, so i can read both, and have an above and below reading of the blower. yes, i like knowing what;s going on everywhere . next to the boost/vacuum gauge is a fuel pressure gauge, (matching autometer, like the ones pictured), both mounted outside, side by side at the base of the rear of the scoop.

the leds on the gauge panel from left to right are: green, ignition on,(have hidden cutout switch), amber, indicator for aux. fuel pump, with manual turn on switch, (also wired into my kickdown switch), and red, indicator for my dual fans when they come on, and a manual turn on switch.

oh, the shifter is a b&m megashifter, custom mounted in the factory console, with a 'ballvalve' shift knob, made of stainless.(thank you work).

just for fun, wanted to share, enjoy folks...........

[Batman]

Nice!!! Gotta love it when it turns out to be something simple.

I like the different look of the chrome nosepiece w/hideaways. Not something you see every day

[mchell]

Unreal to see that thing sticking out of the hood!.......Dang!!

[guidos]

That will be fun to harness!!!

What kind of rear main seal?

[blown 68]

Originally Posted by guidos

That will be fun to harness!!!

What kind of rear main seal?

BOP every time. re-thinking this out now. this is the fourth failure, with EVERYTHING checked each time. there is absolutely no blowby buildup, had a flow meter plumbed into the valley pan, didn't budge a bit, it's got lots of breathing on it.

i am going back today, they were nice enough to let me keep it in the cell, and we are putting some black-lite dye in it, cleaning it all up, running a few pulls, then we are talking it out and and checking to see exactly where this is coming from. wish me a little more luck.........

davey

[guidos]

It is the pan...its the pan...its the pan.......well hopefully. I just bought some of the new rope seals, I sure hope they do the trick.

[blown 68]

well, i got to run the motor again today with the black light dye in it, for a couple of pulls so we could see exactly where the oil is coming from.

a good thorough cleaning behind the engine/around the main took place, put the dye in, and warmed her up. so just for fun, i bumped it up to 6% over, and lowered the peak rpms to 5800. this is on 92 octane, that's why i lowered the peak shut off. it made 653 hp at 5800, 670 lbs/ft of torque at 4500, but it started the pinging/spike/drops at 5600, with 10lbs boost. man, it's too easy to just keep adding teeth and getting more power...........of course until something goes boom.

well, i now know the engines limits on 111 octane, and 92, so that's cool. seems to be about 10lbs on their gauge. (oh, side note, we had a mechanical gauge inline as well, and that one consistently showed about 1 and 3/4 lbs more than the dyno's, he had his mechanical gauge checked today, and it is spot on, so my boost numbers may be reading lower than they actually are, so these 10lb. runs might be higher than that...) the next run was just to 5000rpm, and that was enough to get a drip drip drip.

off she came from the dyno, still in the stand, and off comes the flywheel. lights out, black light on, and guess what. it ain't the pan. you could clearly see a mist around the arc of the block, with mist and puddling around the lower arc/cap, and moisture on the crank. i don't get it. this is a different block and rear cap. the crank has been checked. i'm not callin' anyone out until i know for sure, but the bop seal is the only common denominator. i know some people love them, and some people hate them. i think it's safe to say which side i am leaning on at this point.

if i could spell out in very large letters every expletive known to man, i would, but i won't. i will leave it at this,

i am really god damn sick and tired of this freakin' rear main leak!!!!

mkay, much better. so, back to matters at hand, i'm done bitchin' until i find out more. the engine is staying there, they are a very trusted machine shop that's been around for years. no, pontiacs are not their specialty, but they are very well trained in alot of trouble shooting areas. they are going to pull the pan, check that main, and see how that bop seal is fitting in there. they are also going to pull all the caps. there was some serious copper flakes in the filter, more than i or they wanted to see,( don't even f'ing ask me about THAT little concern...). i am not going to go over this with my engine builder until i get a second opinion on the scenario.

so, as it stands, i got a great running engine, tuned up good, learned a ton more of info. it's going to be several days at least before they can squeeze me in to work on it and give me some information, and i hate hate hate my luck with the pontiac rear main..............

davey

ps, where's that rope seal thread..........

[Silver Judge]

Ahh man, this leak issue really sucks ~!
And if this is the 5th time you’ve dealt with it you must be ready to smash something.


If the BOP seal isn’t doing the trick, there must be some other seal that is able to keep this bad boy sealed. I wonder what the other power adder or blown motor guys are doing ? ?

I hope you can get this figured out and fixed soon

[goquick]

Hmmm, Maybe the new seal that DCI sells?

[blown 68]

Originally Posted by goquick

Hmmm, Maybe the new seal that DCI sells?

it's in the mail now..........

[Big Injun]

It looks to me like your thrust on the crank was not properly dressed. Not unusual...needs to be polished.

[blown 68]

well, i've got a new crank on the way, an ohio. they assured me of all my query's about thrust area/spec, seal journal condition, etc. by the time i turned and polished the one i have 10/10, fixed the thrust,(yes i told my machinist about this, and he overlooked it), re-ground the seal area, and welded it back up, turned and polished it, i could have bought a new one, so i did. would have loved to gone with the forged, but i don't feel like waiting that long to put this baby back together. i feel fine running my horsepower levels with a properly spec'd crank and factory block. although i read a post about the nunzi mains spacers, and that made me curious, anyone done it???

i am also using the shop i dyno'ed at for all future work on this engine, i will settle up with my guy after all this is said and done. he offered to do whatever i wanted to do, so i am sure we will work it out.

i am still undecided on the rear main seal, i have the pre-prepped caddy, the new rope, and i may purchase another bop, so the new shop has their choice, as they will be the one honoring warranty after this point on. they know the history of my woes, and are willing to take it on. they do not specialize in pontiacs, but are a well known performance build shop, around for 30 plus years. i will come armed to the teeth with tips, tricks, and anything else i can think of, to give them before they start the re-build.

i'll keep you all posted for the next chapter, and thank you all for the input, it was all helpful, and that's why i love this place..........

davey

[360Rocket]

I used one of the VITON seals on my rebuild and no leaks.





Viton ® Main Seals-With the mandated removal of asbestos from the factory type rope seals, increased leakage has become commonplace. To address this problem BOP Engineering has designed a rear main seal for the traditional Pontiac V-8’s. These seals are not a retrofit from some other engine, but designed from a clean slate using state of the art technology and the best materials. Testing has shown a significant reduction in drag over the factory rope seal, and no leaks! Available in both 3 main size 301 - 400 engines and small journal aftermarket blocks, and for 3 1/4" main size 421 - 455 engines and large journal aftermarket blocks

[flamedabone]

Any new news???

For the record, mine makes 10lbs of boost and scares the living crappp out of me. She probably has 3000 miles on her of daily driving since March, with out even a hiccup.

Hope yours is back together.

See ya, -Abone.

[blown 68]

long time no update, so here i am with current news. well, i ended up touring with storm most of summer and fall, and the engine just sat at the place where i dynoe'd it, they said they would get to it, never did, so i ended up taking it back FOUR MONTHS LATER.(didn't get charged for any dyno or teardown time, after i went in there and explained the obvious....) brought the motor back to the original builder, and we found some interesting stuff on top of what we had already discovered. it just never gets dull around here does it?

first off, not only did i have a smeared to hell thrust bearing, another oil leak at the rear main, but i also wiped a lobe on the solid stick, a cam i bought from supergas dil. (bummer, i was liking it!!) made great power, but it didn't like something, and i lost one lobe.(had break in/zinc additive, and a proper cam break in.....) so, new cam dead, old eagle crank holding the door open, time to get down to details: why was the rear main leaking, and why did i have such a weird thrust surface wear pattern.


rear main:

it seems that the crank itself was the leading cause for most of my problems on this round. oh, first off, i'm pretty confident the billet aluminum cnc'd caps i was using prior to this last build were responsible for some earlier leaking. a mishap at the machinists with a too long of a bolt going through the crank hitting the cap/seal groove was the first one, when a employee hooked the motor up to his machine to run/check operation/oil pressure. and i believe heat expansion was another issue for the seal area as well. they work great on his race motors, but mine was running for hours on end, making alot more heat transfer to them, being aluminum, i think they just expanded enough to cause problems. i also had some erratic oil pressure on the last build too. with the 80lb pump, i wouldn't see more than 45psi at upper rpm's when fully hot. just an idea, but nothing else seemed to check out bad, and i don't want to blame the bop seal, although that would be the easy target. ...

the rear main seal journal had been cut and re-welded back up to spec on my first eagle, and polished smooth. well, after the last take down of the engine, (with the old caps, steel ones on this last one...)that area didn't get a real good looking at, and upon close inspection on this teardown, there are many hairline cracks and crazes, easily supplying a path for some leakage. i don't recall seeing those when it first came back from welding and polishing, so maybe after many heat cycles this developed? don;t know, not a metallurgist. it wasn't pouring out of there this time, (best seal yet, but still....) but definitely would have made a mess over time. i am pretty confident this is my problem back there, as the block seal groove checks out, the cap seal groove checks out, so all should be good with life back there. the builder has great luck with the bop seal, and despite my concerns, he/we went with it again, believing that we have solved that problem. oh, i have a new ohio crank in there now, looked great, just a little balancing, and she checked out great in the thrust area, and all other areas. so, that WILL be that, end of this story.....

thrust bearing:

it became very obvious that to us both that the thrust surface was in sad shape, and he did not check it very well. he admits to it, and has made good on it. that was part of it. after checking it out some more, i noticed that the block half of the number 4 shell moved for and aft a few thousandths, while the cap half did not. i had excessive wear on the cap half only, with the block portion of the bearing barely even kissed on the front side. they were clevite bearings, there were no extra oil provisions. i believe that when assembled, there was a mismatch between the two halves. this, and the combination of the thrust surface being less than par, could have caused the damage that resulted. the main saddle and cap checked out true when dial indicated, so this lends me even more belief in this theory. he was 50/50 on that being a problem, but there weren't many other possibilities, so, i am sticking to this theory for now.

the motor now has federal mogul bearings, with provisions for extra oiling to the thrust surface. he felt good about the setup this time, with the surfaces being true to each other, so that's where that is at. my clearances checked in a little looser than last time, (i don;t have the numbers in front of me, but i seem to recall about .003 on the mains, and .0028 on the rods...) so we shimmed the 60 pound pump a little more. i had shimmed it prior, and had about 60 psi tops, so this should bring us up to or above where we were before.......

cam:

no real clue to why i lost a lobe, just going to chock this one as a sacrifice to the 'lost a lobe' god, and call it a day. we did the break in like any other time, with no issues resulting. so, after talking to ken (p-dude) i went with a comp hydraulic roller setup this time. he spec'd out a decent thumper for my application, i am confident of hitting the 650 hp mark no problem, as i did with the solid flat tappet. damn, the expense of that switch over adds up fast! i had no idea how much lifters were for rollers, i have always been a flat tappet guy. well, i have now joined the roller club, hopefully no more sacrifices to the 'lost a lobe' god this time......(crosses fingers so i don't lose a lifter bar....)

the cam went in fine, degree'd in great, and new pushrods were ordered after install. oh, it took awhile to get the cam, it seems that they messed up the grind, and ken had to send it back and have them grind another one for him.(thanks ken!!) i also needed to upgrade to better springs to match my pressure needs, so those were ordered from comp as well. it seems that my installed height was already at 1.800", which i had no idea, i thought i was closer to stock, at 1.65 or so. no biggie, my guy spec'd out some new springs, with just a small shimming required to get them where we wanted. he went through the heads as well, lapped the valves, everything checked out ok, so the top end looks good now too. oh, i have searched on here for distributor gear options, being my complete blower has to be removed to deal with the dizzy, i think i am leaning towards the polymer gear for potential maintenance issues, but man, big bucks! i know bop has one, and i think maybe crane? anyway, the idea of not worrying about it, and not having to tear down half of my engine to get to it is becoming appetizing i must say.....


so, the engine is done, i went and saw it today, dropped off my intake and valve covers, and he is delivering it to my house on wednesday. i am not going to dyno it this time, can't really afford it, and i am confident everything will work fine this time(i know i know, famous last words, just go along with me will ya? i am very tired after all of these problems...... i won't have solid power numbers in my hand, but i have a pretty good idea, maybe i will try to duplicate my results on a dyno program, adjust parameters to match my power results, and then just change cam specs and see what it says. i don't have one of these programs, (i'm also a mac guy, do they make dyno programs for macs?) but i will try to find someone to do it for fun if i can't.......


that's that folks, i will update when i can, after it's in the car and running AWESOME,
and let you know how things are going. hope to actually get to the track this year, so i'll keep ya up on that too.

i know there are probably mixed opinions on all these issues, maybe i few "i told ya so's", or "what were you thinking?" and some things that are/were obvious in hind sight and not wanting to admit, but really, i am just sharing all of my info, smart decision or not, my fault or not, machinists fault or not, vendors fault or not, to enlighten the pontiac community. i am doing something a little off to the side of the ordinary engine build, and there were some unproven grounds covered in this project to say the least. but, i think all of this information may be helpful to someone else, and maybe help them prevent some of what i have encountered.




once again, thanks to all on here who have helped me though this.
i love my pontiacs, and i always hope to, difficult or not, as i am a die hard who does not want to give up. just figure it out, learn, and go beat the hell out of 'em.........




davey