Catastrophic Engine Failure
 

Maybe not “catastrophic” in the most real sense, but she cooked her bearings.

I’m at a near complete loss on this one. Inspection of the engine about a year ago after pulling it to replace the dipstick showed a clean bill of health. The only thing I can think of is I made some sort of error putting things back together.

At any rate, took the car out with the wife yesterday and she ran great to our destination. Upon leaving, fired the engine up and noticed the typical valve train clacking that the engine has always had was more pronounced, but it quickly went back to normal.

About a mile away from home during deceleration for a red light, the engine suddenly began making a high pitch growl that changed in pitch and intensity with rpm. Turned into my neighborhood and got the hood open. At first it sounded like an alternator, power steering or water pump. Limped it home and got it up on the lift where I could get around the car a bit more. It became apparent the high pitched grinding was coming from the middle of the passenger side bank, not from the front drive accessories.

Crawled under the car to verify the noise wasn’t coming from the trans, which it wasn’t.

Since the engine was hot, I pulled the plugs and did a compression test. Nothing amiss there, all cylinders pumped between 190 and 200.

Pulled the passenger side valve cover and nothing amiss there either. Only outward issue was the #6 plug which read very rich compared to all other cylinders.

Likewise a bore scope showed a piston without issue. I don’t have a telescoping scope so I couldn’t get a look at the valves. That was all I could really do at the time. First thing this morning I drained the oil. I didn’t even have to cut open the filter. I knew as soon as I pulled the drain plug the bearings were gone.

Pictures attached. I found ferrous material everywhere in the oil. Much of the oil had a consistency similar to molly lube. Anywhere I put a magnet I got metal.

Attachment 634637Attachment 634638Attachment 634639

I haven’t decided what direction I’m gonna go with this currently. I winterized the car and put it up for now while I think about its future. Once I make some decisions I’ll develop a plan, then pull the engine and see if I can diagnose what happened. The engine didn’t seize, so I’m banking on not having any block damage. With the amount of metal that’s gone through this thing, it’s a total rebuild if I go that route.

I’ve thought about selling everything, including the car, but that’s probably an emotional decision more than anything. I’ve considered an LS, but money is probably a wash there, once you account for the swap bits. At that point I’d rather have a the Pontiac engine.

Assuming I go the rebuild route, my plan is to get the engine torn down first and take stock of what may be salvageable, specifically cam and crank. Then start talking with some machine shops.

I’m giving thought to assembling the engine, but I’d probably have more money in tools and measuring devices than it would be to pay to have it assembled.

For those of you that have gone through this process, any insight you have would be great.

I’m going to try and keep this thread as a build thread to cover what I’m doing. I’m going to start calling around on some things this weekend and give myself a bit of time to get past the emotional aspect of this.

Thanks for reading!

That is a major loss.

I remember the striking photos of your beautiful car - you are clearly invested so I hope you can find a way to resurrect the engine.

Sorry to hear.

How about you give us a refresher on the basics of your build so perhaps we might better evaluate what could have caused the failure ?

What heads, compression ratio, camshaft and etc.

Hey Jason, I'm sorry about your trouble. I know it's hard to be in that spot.

I bought your old heads from you, and can help you being semi close(Oklahoma). Many solutions available.

That’s a bummer.

I don’t know but that high pitched growl sounds more like it started to locked up a needle bearing on one or more of the roller lifters.

Having a crank bearing fail and driving it home it would make a knock, and the shavings probably wouldn’t be sticking to the magnet like described, many of the filings found would be nonferrous.

Sorry to hear this Jason. Step one take it apart and see what you have. Hopefully things are better than you're thinking.

Been there done that. Don’t swap to an LS and don’t sell the car.

Hate to hear this. How many miles did you have on it? Looks like something definitely ate itself, but maybe it's not a total loss. If it was a lifter or a bearing to have a knock or a tap. Not sure what a growl could be. Initial thought is maybe the oil pump or timing set. Hang in there. I know it can be frustrating. I got pretty adept at pulling my engine apart last year.

I think in you second paragraph here within the revaltion of the valve train clacking noise that goes away you will find the root cause of this distruction.

Sooooo, how was the oil level before and after the drive?

Its just an engine, pull it and get it rebuilt. Try to find a running engine nearby and keep burning gas.

Thanks for the kind words. I'm starting to build lists and make calls today.

The engine is a 73 455. Factory rods and crank, TRW Pistons. It was originally built by the previous owner and was fresh in the car when I purchased it in April of 98. I changed the top end in 2015.

As cast KRE D-Ports 85 cc, estimated 10.25:1 compression
Comp Hydraulic Roller 232/238/112+4
Lunati lifters
Torker II intake
FiTech EFI

It's backed by a performance upgraded 4l80e, TSP triple disc billet face converter and a Moser 12 bolt.

Yes, I remember those old #62's, I hope they did well for you. I don't know that I have your number anymore, can you send it via DM? Thanks!

That is possible. These lifters have always been loud, so I've somewhat learned to ignore them as they've been checked annually or bi-annually at the least and never never shown signs of having an issue. But it's a known problem area of course.

Thanks Paul. I'm really hoping the crankshaft can be salvaged. That would be beneficial to any build plans and dollars out. Knowing the engine has to come out, I'd be going through everything regardless. I'll likely spec a larger cam and I've wanted to get a set of forged rods in this thing for a long time. I guess now is that time.

I'm still looking at all options, but even my wife wants to see the engine get rebuilt instead of any swaps or selling the car.

I don't know how many miles total the shortblock has on it. The engine was fairly new in 1998 when I purchased it, but I don't know how many miles the previous owner has put on it. He didn't provide receipts or anything, so it was always a big unknown. That said, with my driving of the vehicle, I'd say the engine has somewhere around 30,000-40,000 miles on it. Could be quite a bit more, I know the previous owner daily drove the car.

I would describe the sound as if an accessory bearing failed. That same type of high pitched grinding that is steady and constant. Then magnify it's loudness and intensity by 10. In regards to the oil pump, I put in a new unit from Nitemare performance last year when I had the engine open. Did their pro-pump along with their HD shaft and went with a copper gasket. Checked driveshaft to crankshaft clearances were good and retorqued bolts to 30 ft lbs.

I have a feeling you are probably on the correct path here. Considering this thing looked great last year when I had it open, I would almost bet that a lifter started to go south and it started taking everything else with it.

Oil level was good. The engine doesn't consume oil and doesn't leak. I drained a full 6 quarts.

I'm looking, but no much in the Colorado region that I've been able to find as far as running engines. I might just be down for a while.

Since there’s now been a good amount of grit flowing around in the motor once your tare it down inspect the piston skirts for imbedded grit and of course scratches.

Also pull the oil galley plugs so a hot tank session will remove any hung up grit that might be hiding in there, especially if there’s old sludge in there.

Be sure to take the oil pump apart and check for scratches on the pump cover and gears and double check the bypass chamber for grit.

Once you get it all good and running again you will be surprised how much faster the motor will rev up with the lighter aftermarket rods in there!

I would simply plan on new pistons as well. These are original TRW forgings. Strong, but certainly heavy and old tech. It would be really nice if the cylinder walls could be honed only, but if I've got to go another 10 thousandths I'm sure that's not a huge issue.

I'd like to get a modern ring pack in there and I'll probably go with a gapless top ring.

Hopefully the pump is okay and can be cleaned. It was just installed last year.

WIth a rebuild I'm going to do what I've wanted to with this engine in the past but didn't have a big reason to.

My plan would be as follows
-Retain the factory crank. If it's not salvageable I'll go to a forged 4.25" crank.
-Forged rods to support some additional power and rpm
-New forged pistons with a more modern ring pack
-Roller cam, either Johnson lifters or topped by HIPPO solids, something in the low 240's on the intake side, probably using UD lobes.
-Have the heads gone through, to include a decent port along with porting and matching the TII, move to 1.6 rockers.

Basically I'm thinking of it as kind of a max effort street D-port engine. I don't have any vacuum accessories that I need to power, so I can go a little larger on the cam. The drivetrain is built to handle around 700 hp. I'm not going to get anywhere near that, but if I could pull up to around 570 or a little beyond, I think that would sit in the platform nicely. Any more than that and I think I'm going to be in a traction deficit.

The block is drilled for 4 bolt mains. I don't know if I need to do 4 bolt caps at this power level, but I might go to studs regardless for a bit more piece of mind.

Idea here is to do it once, do it right and not cut corners.

Damn dude, that really sucks. I'd be devastated if that happened to me. How was your oil pressure reading when you got it home?

The FIRST thing you should do is count on pretty much all of your thinking right now to be emotional and even cynical.

Step back, take a week or two off to mull it over and accept the reality of this failure - it's technically a grieving process, in a way, just like any major problem. It's a big financial setback to fix. Once you take some time to digest that this happened, you'll be able to think more clearly on how to approach it rationally. Selling the car is not the right way to go. The car isn't the problem, the engine is, and if you really want to just get the car to move so you can drive it you can spend 2k and dump a cheapo crate 350 Chevy in it and some quick conversion parts and hit the road. I know you won't do that, but you get my point.

Just give yourself time to step back, let the shock and emotion wear off, put a frame around the situation, and approach it rationally.

If you do custom pistons you dont have to do in 10 increments!Let the machine shop tell you what is needed.You might only need to go 5 more to get what you need.Custom means CUSTOM!The ring selection comes into play most of the time.Tom

My 455 died rite after I bot the car so...condolences

I had trouble finding a used one and it was going to take months to rebuild what I had. I even talked to Lenny Williams about a crate which was somewhat reasonable during covid.

I found a used motor a couple states over and rolled the dice on it....so far so good

Hopefully parts and time are on yer side!

Yeah it definitely hurts on an emotional level. While the money side of things stings a bit, it's not a huge concern. At least in that way I'm very fortunate.

I can take the time hit while this is done. If I absolutely really had to have something in this car right away to get some driving in this year, I could have an LS delivered in a couple days and do the swap.

I am definitely not letting myself make any hard decisions yet, but if I end up doing the rebuild, I'll take that time to do some cleanup in the engine. The fender wells and firewall could use a new coat of paint. I'd spend some time really working the gaps and fitment up at the nose, which has been a weak area for this car. I can also do a proper wire tuck with the fenders off, so that when a shiny new engine drops between the frame rails, it really pops off.

I'm trying to think of this more as an opportunity. Make the car a bit nicer, and a new powerplant that I know everything about and gain a bit more piece of mind. Not knowing how the engine was built previously, but knowing it was a pretty basic factory rebuild, I always had it in the back of my mind that I needed to watch what I did with it.

This is a good point. Is Autotech still the go to here? I'm assuming the typical vendors probably also have some custom sizes. Ross, DSS, Icon etc.

I thought about trying to see if there are any crate short blocks available. I might call up Len on that as well. But I think time is going to be there no matter what. If the block somehow is garbage, I might lean more in that direction.

Earlier this year, the 6.2 liter LS in my daily driver Yukon had 2 rod bearings fail and the engine seized on the freeway with 3,200 miles, so there's that. Still had the paper plates on it.

If you're keeping it or selling it, you'll still need to put a working engine in it, so there's that.

When the 440 stroker in my car died, the rebuild quotes here in LA were so high that I ended up buying a 462 from Kaufmann. They'll break it in on the dyno, tune it, then crate it up and ship it to you ready to go.

Good luck!

What was your oil pressure gauge doing while all this was going on? My best guess is you spun a rod bearing and lost oil pressure causing the valve train to become noisy. As the rod journal ground away at the bearing (the growling sound) the clearance was partially restored and oil pressure returned (albeit lower). This quieted the valve train some. You probably wiped out the main bearings too but only an inspection will tell. An event like that usually starts with a momentary drop of oil pressure or a fluctuating oil pressure gauge needle that wiggles a bit at first and then eventually drops.

Yes, a lot will depend on costs involved here. If it's up there quite a bit, I may end up going a route like that.

I keep a pretty good eye on my oil pressure. It's never fluctuated that I could tell. However one thing that I did notice recently, probably within the last month or so was that the pressure was ever so slightly slower to come up after engine start and during cruise, it was actually running about 5psi higher than typical. I attribute that probably to all the sludge that was building up in the oil and it's increased viscosity.

Im still using Autotec,Paul K might be able to help you with them.tom

Sorry to hear about your troubles. This story is eerily similar to mine. Old build with factory rods, crank, TRW slugs, etc. Decided to upgrade to AL heads. Twenty year old cam wipes a lobe a week before I was going to install heads.. New flat tappet cam wipes a lobe on break-in. Upgrade to roller cam...block cracks in #7 cylinder wall.... Not to mention tearing it down to the bare block twice to clean out the trash between failures. That's why there's a $400 5.3 between my frame rails now. Best of luck to you!

Sorry to hear this. But I doubt its catastrophic. I would lay money its the typical hyd roller lifter having problems. I mean, how many times have we seen this ?
Its a street TRW 455 engine, they are really tough if you don't over rev them. I POUNDED on a TRW 455 for decades with steel rods and its still OK.
So I bet you have a .030 over 455. You can get modern pistons with slots for gas porting, better than ported pistons which can clog. I like file fits over gapless.
You can probably go .010 over, and do a ridged hone with TQ plate. And who knows, your pistons and bores might be OK enough for a new set of rings. Upgrade to steel rods, new rings and re balance.
Myself, I would not touch a hyd roller lifter with a 10 foot pole. Maybe if the new Comp lifters turn out tough and so far so good with them. Consider the BAM solid roller lifters with steel bushings and DLC option. Their reputation is tough a nails. Get some Crower SS Endura rockers and run a stud girdle or maybe even go shafts if you can afford it. Sold lifters do not need adjusted all the time like many think.
Whatever you do, drill your main bearings to line up with the oil hole in the block the oil actually comes from. Its very important to the long life of a Pontiac.
Consider building it yourself, you sound like a smart guy and the satisfaction you get is so worth it IMO. You would spend far more paying a pro to do it. You do not need a ton of measuring tools either. But you do need to pick a shop with a impeccable reputation to machine it.
You are going to be fine. Its just a process and learning and doing is fun and satisfying.

I do think the hydraulic rollers may have been part of the cause here. I wouldn't look at any other set on this except the Johnsons, which currently have a decent reputation.

I'm certainly looking at the idea of solids however. My only worry has been idle time. This is a street car and while I don't typically drive it in stop and go traffic where it may be at idle a lot, it does see some idle time. This seems to be somewhat of a known problem area for solid rollers.

At least locally, it appears that assembly costs on a rebuild run around $750.00 or so. So it's probably a wash after purchasing tools. I would need pretty much everything. All I currently own in this department is a torque wrench and dial calipers. I'm thinking the minimum assembly tool list looks like this.

Micrometers
Dial bore gauge
Deck height gauge
Timing wheel
Ring compressor
Ring filer/squaring tool

Anything I'm missing there at minimum?

If i were to go street roller i would go tight side of specs on crank bearings so thinner oil can be used with direct roller lifter axle oiling along with the HP. SD. oil pump elevated idle RPM ... along with assuring lifter oil band gets pressure constantly

everything ive outlined is to promote the highest possible amount of oil at the most critical parts of a roller engine

My heart says steel residue in the oil from hydraulic lifter/cam lobe failure but my head tells me steel filings from the rod bearing shells and cast iron from the rod. Hoping for the best (least expensive fix)(lifter/cam failure).

I have been doing this a long time. I do not have a bunch of micrometers. Just a 0" to 1" and a 3" micrometer and rarely use them.
No dial bore gauge either, but I will get one to check used bores. They are not expensive and if you are going to bore or ridged hone this thing you do not need one.
I mean, so if you want to check every little thing and you have extra cash there is nothing wrong with it. But I have a guy, a machinist and if he says your rods and mains are this clearance they are exactly what he says they are. Every time I have checked its been spot on.
But you need snap gauges to check your main clearances with a micrometer too.
No deck height gauge either. But I do have a cheap Harbor Freight 12" digital caliper for checking pushrod length and you will need one of those. A 6" too because everyone needs one of them. The 12" can be used to get close on your deck height. Deck to main and do the math.
You will need a adjustable pushrod to check their needed length.
You need one of those Summit adjustable ring compressors with the big hose clamp. Cheap. Ring filer, cheap.
Get the Summit degree wheel, cheap and you will need one of those Comp Cams crankshaft sockets to be able to turn the crank while degreeing it.
And Jegs makes a real nice and not expensive balancer removal-installer kit (77$) and you will need one of those for a press fit balancer. No slip fits on a real engine.
Good torque wrench. And if you are wise and use Molnar rods Lisle makes a torque angle meter for 60 $.
But you can buy a decent Harbor Freight torque wrench and does angle too for 180$.
750$ sounds pretty cheap for assembling a engine. Does that include degreeing the cam ? Guys I know charge a lot more than 750 $
You could just run a sft cam lifters and not worry about a thing after you get a good break in. I ran a chevy sft lifter in my 455 for years and it worked fine. Did not modify the lifter bores either for the oil band difference. Probably should have and its just a little labor and easy. I would be temped to run a chevy tool steel lifter on a custom Bullet sft cam and do the lifter bore mod.
Can not imagine one going flat.
And I just got off the phone with BAM lifters. Their lifters are pressure fed and have been shown to be practically indestructible in race engines.
With the spring pressure you are going to run you could not hurt them.
IMO get a custom Bullet SR cam from Tim G. and run the BAM lifters.
Not cheap but noting about this hobby is.
Some good pistons, right ring pack with ported rings, lighter steel rods and a custom SR cam and your engine will run So,ooooo much better and put a smile on your face.

I have only spun one rod bearing in life back in 1982 sounded like an elf in my oil pan with a 5lb sledge hammer hitting the block hard every time a certain cylinder fired, the tempo increases fast with any throttle input, didn't throw that rod but sounded like heii

once you hear that sound there is no mistaking it for anything else

Hi Jason, what a bummer. If you need an extra set of hands, let me know.

Appreciate the input. I have a number of those items already. The install tool, digital caliper. I could use a better torque wrench.

As far as the assembly cost, the local machine shop shows pricing for complete engine rebuild with and without assembly. The difference was $750, so I figured that’s likely the price. I haven’t actually talked with them yet, so that would be different.

Is the idea on the SR cam still to add about 10* @.050 compared to a hydraulic cam? Meaning I was intent on running something around 242* on the intake, I’d actually want to spec a SR around 252*?

It appears the Bam bb1 lifters are comparably priced to the Crower enduro rockers. A couple hundred more than the Johnson hydraulics.

Definitely no tapping on my end. I still don’t actually know the cause here however.

Appreciate it. If I need a hand I’ll certainly let you know!

If all cylinders are pumping 190-200 I doubt you have a lifter failure. With a lifter failure you would certainly have a dead hole or at a minimum one that pumps way out of range from the others.
Hard for me to see in the pic but that looks like bearing material, something in the bottom end.

Sorry to hear but it happens to all of us if you play with these things long enough. Look at it as an opportunity to make it better :)

Pull the valley pan and have a look. I've lost 2 HFTs over the years, and both made sharp slivers of ferrous metal. Growling would also make me think timing chain or valvetrain. I guess if it spun a rod it might growl before it knocks, in that case you're lucky you saved the block. But my bet is still valvetrain. I've found that badly worn intake lobes will show higher cranking compression due to early intake closing.

This is a hydraulic roller engine. Still certainly could have had a lifter failure.

The engine is coming out regardless, so I won’t bother with taking the intake manifold off while it’s in the car.

I’m waiting to hear back on a buy quote from a local shop on the car. I don’t anticipate much. Barring some figure I can’t pass up, the engine will go to my local machine shop for rebuild and the heads will probably go back to KRE for rebuild and upgrades.

That should cover it; just make sure you purchase good quality mics and bore gauge. Fowler is a good quality brand with a reasonable price(.0001 calibration) You don’t need Starrett or Mitutoyo unless you are planning to machine and build engines professionally. A good set of feeler gauges would be required to set ring gaps. Deck height gauge? Piston deck height or block deck height? Piston deck height only requires a 0-4 depth mic with a four inch base; a block deck height gauge is serious money ( $500 for the one that BHJ sells). As I said earlier unless you are planning to start machining and building engines professionally you don’t need one. Your machine shop( find the best one in your area) should be able to measure the block height before and after milling the block decks. Put the funds for the deck height gauge into making sure your crank ( whether the OE or an aftermarket 4.250 stroke) is “on” stroke (+/- .003-.005) and has no taper (less than .0002 per journal) and no O/R (less than .0005 after final polish). Any questions feel free to PM me.

I spent a couple hours down at the local machine shop yesterday putting a parts and build list together. After taking some time to look at options such as an LS swap and even parting with the car, rebuilding the engine makes the most sense.

The machine shop is going to source most of the parts for this build, but there are a couple things I'll need to get on my end.

We are going to utilize the factory crank, unless it can't be salvaged.
ARP main studs
Eagle rods
DSS +.040 pistons and their plasma molly rings
It'll get Clevite P series bearings throughout
Thorough hot tank cleaning, all galley plugs removed, magnaflux the block
Check and clean up line bore
Deck the block (aiming for deck height around .002 with a .039 head gasket), they use a BHJ fixture
Hone to +0.040 with torque plate
Grind crank 20/20 as well as grind for 1 piece BOP seal
Balance the assembly
Cloyes true roller timing set

The machine shop is going to do the full assembly. This is the wife's ask, considering the amount we'll be spending, I'm not in a position to disagree. They will do there wet sump race engine assembly. They build lots of circle track stuff, so this represents their most detailed assembly procedures.

We also have a full day dyno break in and tune in the quote.

On my end I will have the heads rebuilt with porting and replacement of any parts that need so. Likely springs as well to support lift in the .570 to .600 range. I will supply the cam and lifters as well. Final piece on my end will be a new Nightmare performance oil pump. I'll be reusing the Nitemare performance pan as well as my BHJ balancer.

With the parts and head/intake work on my end, it looks like my all in cost is going to be +/- 10K

I'll have the engine out and disassembled in the next couple weeks, then I'll get the engine dropped off. They have a current lead time of around 3 months, so assuming I don't end up waiting on parts, I should have the engine back probably in October sometime.

On the cam, one thing I am leaning towards is using a cam with higher lobe lift to get around the .580" lift mark so I can continue to utilize my 1.5 rockers. There are some comp lobes, as well as lobes from other manufactures that achieve close to if not right at .4" which gets me where I need. However, this is being achieved by reductions in the base circle and I do have concern about keeping the lifter's oil bands in the correct locations. I've been satisfied with my Harland Sharp lifters, so if I need to order a new set of 1.65 rockers, I'll spend the money.

Cam will be a hydraulic roller with Johnson 2112OPR lifters. These are the .93" travel option.

Compression as designed in the build above is going to end up being around 10.35:1

I'm open to any and all suggestions here. My initial thoughts are a cam around 242/250 on a 112. The car weights 3600 lbs with me in it, is backed by a converter that stalls around 3200 and a set of 3.31 gears. I use short 26" tall tires. I don't have vacuum accessories that I need to power, but I do need to keep vacuum around 8" at minimum for my FiTech system. This is a street car, so it does need to have okay manners, but I definitely want some attitude. The 232/238/112+4 cam that is in it now is too tame. It made good power, but idled too smooth for my taste and makes power a little lower in the power band than I'd like.

I don't want or need to go crazy with RPM here. A shift point around 5700-6000 rpm is probably ideal.

Sorry for the setback. Will stay tuned to find out what the source of all the metal was.

Comp makes that cam in a 400 lobe lift,that will get you there.Tom

The BHJ block fixture is one of the greatest inventions to aid engine machinists. No matter what marque of block you are machining achieving equal block deck heights is as simple as sitting the block in the fixture and adjusting it.

Sounds like a solid plan- is 10.35 compression enough for the 242/248 cam?

I had to look these up as well. I wasn't familiar with the machine. They also utilize one of the new Rottler honing bays. They were pretty proud of that piece of machinery.

I think it's on the edge. I don't have a heavy car and I've got enough stall that it may not be an issue. But I'm talking to a number of different people and taking opinions anywhere I can get them. Something in the "old faithful" size, or very slightly larger may be a better suited choice given the estimated compression ratio.

Finally got a full weekend that I wasn’t busy, so I was able to get the engine out and disassembled.

I didn’t document much as I just wanted to get things done, but I’m left a little befuddled. No major smoking gun on what caused the engine to start eating its bearings.

Starting with the intake, the gasket had failed at the #6 cylinder which explains why that hole was far richer than the other cylinders. The gasket failed enough that it was covering about 3/4’s of the port. I’m nearly positive it ingested some of the gasket as well.

All of the rod bearings showed severe wear down to the copper. The bearing for #5 appeared to have turned slightly, but the halves hadn’t ridden on top of each other.

The mains looked mostly okay, but a couple had what appeared to be some fretting.

Overall the crank is in decent condition. I think it’ll get by with a polish instead of needing to be cut.

I didn’t measure anything but I had a couple of clearance concerns. It appeared that the crank end play was very tight. If I had to guess, no more than .005 and it didn’t have much of any free clearance. Additionally the rod side clearance on #1 and #2 was pretty much non-existent. #3 and #4 were also fairly tight, certainly less than the crank end play. Remaining rod side clearance was quite a bit wider.

Cam, cam bearings and all lifters don’t even have a witness mark on them. The rollers anre tight, roll freely and Have not pitting on them. The cam lobes likewise have no wear. Everything there looks really good. Only a couple small nicks in the BOP composite distributed gear. I’ll grab a new gear for peace of mind.

I’ll drop the block and related parts at the machine shop tomorrow and send off the heads and intake for work as well. If all goes well I’ll hopefully have the engine back sometime in September.

Very interesting findings- what is the history on the bottom end?

Is the intake being ported?

I don't know much of the engine's history. When I purchased the car in 1998, the engine was claimed to be fresh at the time. The previous owner didn't furnish any receipts or documents related to the engine build.

I did the cam, lifters, head and intake in 2015. So other than knowing the engine had factory rods, crank and TRW pistons, how it was put together, with what type of bearings etc. was always a mystery.

Yes, the intake is being ported as well to match the heads.

Yeah I didn't think you had a roller lifter problem based on your other diagnosis.

The fact you got 16 years out of a short block you don't know the history on I'd say you did pretty good. Now you can build it back better and not have to sink as much money in it as you might have initially thought

I'm still doing the full build, so the money isn't necessarily changing. Although, I'll be able to sell the cam. I know there's a couple people looking for stump puller type cams.

You're correct, this will be the engine for the next 20 years or so.

Yep, just as I described. The bearing gets hot, sticks to the crank and turns enough to restrict the oil hole. The bearing shell rides up the connecting rod journal. The locating tabs act like wedges to pinch the bearing against the rod, taking up the oil clearance and the whining noise ensues (like a a worn pinion bearing). You have to run it for quite a while while before it grinds enough clearance for the knocking to start.

Best of luck on your rebuild.

This is pretty much what the machine shop said as well when I dropped it off this morning. I had them look at the thrust bearing and they noted that it was normal.

Sounds like the engine just got old and tired. If this 10K investment lasts another 20 years, I'll be happy.

You got your money's worth. x2!

Build it bigger and better!

Sounds like you started to stack a bearing on a cast rod. Shut her down just in time to save it.
I bought a 455 that had a severely stacked bearing on a cast rod, crank was just 30 seconds from snapping a rod.
Something you need to inform your machinist about. You need to bore it at least .008 under, not .004 under like you do with a Chevy.
The problem is Pontiacs distort .004 or more a 1/2" under the head bolts. You want your bores completely "round" after all.
If he can bore AND hone with a tq plate, great.
I asked for that on my 461 but he could not do it with his equipment. So he bored it .010 under and honed the rest with a tq plate.
Oh, I would run a Molnar rod all day long over a Eagle and they are about the same money.
I had to have a set of Eagles honed on the big end as they were tight when new.
Good luck with your new build. Getting it back by September would be fantastic.
A stacked rod bearing is why I tell all who want to listen, by forged rods. On just about any engine unless dead stock.
These things are too expensive to do otherwise.