The 400 let loose again; this is getting old
 

Meaning? This morning on my way to a car show, my motor likely spun a bearing only 253 miles after it was repaired last year, due to a spun thrust bearing. A year or so before, it went only about 950 miles after it was rebuilt after two bearing and a rod went. So, the same very reputable builder after it "went south" last year paid for the labor and I picked up the parts cost. What should I ask for this time when I call his shop tomorrow?
My Buddy who's rebuilt quite a few motors over the years said there's nothing I could have done to the motor to make this happen unless I was racing it, hardly the case. This sucks. Thoughts?

Rob in Nor-Cal

Sorry for all your problems.

:(

Time to learn how to rebuild it yourself, I'd say?

:)

Is it a manual or automatic transmission? Sometimes thrust bearing issues can arise from improper clutch adjustment or other trans related issues.

Yea i got a thought on oil pressure: did the oil gauge reading chatter at any RPM?

i lspun a rod bearing due to low of an oil level. My remedy was a deep sump pan, a crank scraper & lots of oil.

I've never had a bearing let go in any of my Pontiac's or even sbc's. Broke some rods in honda motors, I was young and ran the pi$$ out of everything haha.I still do, not my commuter anymore lol.

Something is amiss. Do you happen to know what spec he used for the main saddle size? The book says 3.188-3.189, but I keep mine at 3.188-3.1885. What was your oil pressure?

Get what you can from that engine builder and find a guy who knows Pontiacs better. Something has to be way wrong.

Only failure's I've had or seen were due to lack of lubrication.

Pontiacs really are not a issue!A machinist that screws up one make will screw up another.Some of the best chey and ford builders have built some of the most powerful pontiacs.If the person that builds it does not check and double check the machine work that is a problem.All builders can make a mistake as they are human.With yours something is really amiss.Tom

I have had 2 failures on the dyno with breakins.One the builder did not check ALL the side clearance on ALL the rods as one was tight and the other the builder did not check the clearance on the rear main.Both very highly respected engine builder.**** happens even thou it should not.That is one reason I like putting fresh engines on the dyno.Usually find a problem before they break.Tom

X2!
There's been talk here about builder's knowing what they are doing concerning specific Pontiac builds...BUT a real engine builder will know what to do to a Pontiac, IF he's legit!
My builder friend is a Chevy guy, and aluminum hemi's...but everything he touches is better than could be imagined...no details spared..

I'd tell the builder what happened, see how he responds, go from there, possibly another shop...

This isn't a Fulper build, is it?

I had two newly built 455s in a row eat bearings, with few miles on either. I blame the quality of the machine work and the builders lack, or inability, to check clearances for both. It's cheaper in the long run to pay for quality work up front. Many builders just slap the new parts together. The result is poor ring seal, poor deck height and assembled bearings diameters that don't match the specified journal diameters and chamfers.

I do believe that a quality builder can build any brand engine but there may be a little truth to "Pontiac" guys.

1. They know what to watch out for in terms of main and cam journal alignment, oiling, funky freeze plugs and combustion chambers.

2. They've developed a good reputation for years of quality work.

Fulper actually uses a REALLY good machine shop!Tom

I was pondering the same.

After 950 miles, the "you buy the parts, I'll do the labor" arrangement doesn't sound very fair to me. I'd find a new builder and tell everyone on here who to avoid.

Sorry to hear all of this. I hope you get it sorted out.

Not isolating just pontiacs I've owned; but I never had a crank, head, or block break, nor have I ever "windowed" a block, but I had Whole bunch of other stuff go wrong. Spun several bearings, scored cranks, blew head gaskets, bent stuff, etc.

Once had a transmission manage it self into second and third simultaneously.
Once thought the grinding sound was a bad throw-out... There went that crank.
Fun getting home with no clutch pedal.
Bad wheel bearing I thought - nope someone tried to kill me.
Lots of unwanted attention from a rad hose popping
balancing the fear of grenading the engine vs crashing of a stuck throttle
A pro a starting with no starter
One could not only find shattered glass under my carpet, but also halon
And there's more - lots more

Joe Sherman?

Joe Sherman does not have a machine shop.Fulper uses a guy in or around the Riverside area.Dugan is the shop.Tom

Dougan's in Riverside did all the machine work on my recent 421 HO build.

Top-notch work and great to work with.

Bart,are you going to the show this sat?I still have your dip stick and tube in my trunk!Tom

Is your builder in Nor Cal also, if you don't want to name the shop can you give the city.

I've heard of them. They do a LOT of the magazine project engine machine work. Excellent reputation.

Sounds like somebody is using aftermarket fasteners, but factory torque specs.

Around here the problem is finding someone who can grind a crank properly. Bearings don't live long if the journals have runout and rough finishes.

Shouldn't be that difficult. By run-out, I assume you mean taper?

Shouldn't be that difficult....? No, it shouldn't be, you're right. So why is it?

Runout /= taper

Good question, Will. People not taking the time to setup the grinder correctly, not dressing the stone enough times during the grinding process, coolant breaking down (i.e., ph level off, dirty filter, coolant concentration off), not using enough coolant flow while grinding, too fast cutting rate, too slow cutting rate and simply just not giving a damn. I'll give you an example: if I was grinding 15 6BT Cummings cranks, I would dress the stone after grinding 5. Half way through, I would shut down the stone drive and check the radius on the stone. Our RA spec on crank journals was 15 or less when it came off the grinder. After micropolishing, an RA of 5-7 was the requirement. If they're grinding crank journals oblong AND with too much taper(.0002 is max on a V8 crank journal), I would suggest "neutralizing"them to resolve the problem. That's just plain, old STUPIDITY...

There was one shop around here, about 30 miles South in Tacoma that I could trust and they went out of business a couple years ago.

I haven't built any engines since then so I really don't know where to go now. I've had several cranks screwed up by other shops. Got one 428 crank that looked like it had been polished with sandpaper and not one of the main journals was true to the crank centerline. I don't have a good way to measure stroke or index in my garage and I hate to think how bad that might have been off on that crank... Had to send it back out to get another .020" taken off it to true everything up (ended up .030" under and was turned .010" the first time). Strangely, didn't really have any issues with taper on that one.

Had another crank come back where they didn't even touch the thrust face and it had pitting from corrosion. I pointed that out to the guy at the shop and he said "that's not a problem, it'll be fine." So, I took it to the shop that's now out of business and they laughed and fixed it for me. That was a Toyota 22R crank and the first shop hadn't even bothered to remove the screw-in plugs from the oil passages in the rod journals. Second shop said it was full of junk.

I don't understand how shops that turn out crap work like that can stay in business.

I've got ONE guy I trust to grind a crank. I've known him for nearly twenty years. If Fred ever gets out of the business, I don't know who I'll send cranks to for grinding. I could do it myself, but one doesn't purchase a $50,000+ crank grinder to grind a crank or two a year.

We are lucky to have a few good crank grinders here in so cal.2 of them learned their trade from Joe Reath.Tom

Been too busy doing OT at work on Saturdays lately, otherwise I'd like to go.

Will try to come by your place sometime next month if I can work it out. Bart

No problem,not going anywhere.Tom

That marriage ended a few years ago. I rate Dougans as the best shop in SoCal, so you have to look elsewhere for the problem. 'Nuff said...

That marriage ended a few years ago. I rate Dougans as the best shop in SoCal, so you have to look elsewhere for the problem. 'Nuff said...:rolleyes:

Joe was a legend, Tom. My old friend, Bud, used to talk about Joe's skills in grinding Offy cranks. Like Bud said.."Always on stroke, always on spec"

Joe was a very dear friend,started doing biz with him when I was 17,his wife Deli is still with us and doing well.The brains behind the biz.Tom

To catch up on the replies, all of which are greatly appreciated. The car has a 4 speed manual. When it went out at 940 miles, it didn't let loose it had a knock at the rear of the engine that was the thrust bearing. Oil pressure was good, gauges work fine. I have 3.23 gears and ran it in 3rd gear at about 3k rpm for a couple of miles on the freeway, but had taken it on the freeway already after this build. But, back to the thrust bearing and tranny. Maybe the shop that did the R and R of the motor didn't get it right, but could I have even gone 250 miles if it was amiss? I would have heard something. The builder is Joe's Engine Shop in Concord CA. Veteran builder, only takes motors, does not do R&R. Our 94 year old friend who owned a shop was Joe's mentor. He has done many many engines, including racing motors over the years. Very reputable. I'm pretty sure he did the motor himself the 2nd time (after the thrust bearing chatter). I know I need to break it in for 1k miles or so, but does that really mean not taking it over 2k for the first 1K miles? My buddy said no way I'd have to have been racing it plus had it overheat to have it come apart again. Just praying my block is ok, this car is original drive train Concours restored.

The 'break-in' is usually for the rings seating in the bores.

Bearings don't need 'break-in'?

:confused:

No you can go over 2000 rpm, that is non sense. Since you have a 4 speed that rules out the convertor pushing into the crank and killing the thrust bearing.
Now, when you have it balanced, the shop should have asked for your harmonic balancer, flywheel, clutch and pressure plate. If you run a heavy flywheel and it is not balanced it will hurt bearings.
Was everything neutral balanced?

Am hoping for a forensic diagnosis on this one. Interested in cause on your engine.

Have my 455 in machine stage now. I thought low mile short block was in OK shape had built many years ago but only 2000 mile. Did some hard runs years ago though. Had one really bad spot on crank from bearing issue. Had block align bored years ago for 4 bolt cap add. Am told it was done poorly. It is being rebored and man I am kind of paranoid now. Got a new old crank that is nice so that is not my worry.

Every time I read a thread like this I get paranoid and go down and check things over again ... at this rate I'll never get the nerve to seal this thing up and start it :)

No, they don't. I've never "broken-in" engine bearings...:confused2:confused2

Being that the only thing contacting your bearings is oil, I would venture to say that they don't require a "break in". If anything other than oil contacts them, you get what the OP has.

Does anyone else feel that there is a strange connection between worrying if an engine going to fail and it actually failing? I don't think I've ever built an engine that I didn't care about that had a problem, but ones that you do care about are way more likely to have a problem.

When I think about the engines I literally through together in a filthy garage as a kid that went thousands and thousand of miles .... I wonder why I worry so much about one where I take my time and do everything right.

The old saying .... "Think long, Think wrong"

Well, like any other emotion; if one doesn't have it, they're probably not right. If it controls one to the point they don't start that motor, they're probably not right either.

And it seems that worry promotetes being mindful, so I'd go with maximum worry until it impedes performance. On the other hand, an emotion can sap energy from a person, and nothing makes a person careless like being tired.

Worry moderately I suppose.

That's why hillbillys can slap together a 350 to go muddin while slobbering drunk and it'll hold together. But when those engines do fail it's a magnificent failure

Contact Vic at Victory machine in San Jose. 408 266 7570

I am working on a Chevy 350 TBI Engine for 1994 GMC K1500 Suburban now.
Just a daily driver & my tow rig machine.
I forgot how cheaply made they are compared to A Pontiac V8 & Olds V8.
Like a Dinky chuna toy.
Should not say that because I have an old Corvette..

I read through all posts from the past on this thread.
Just Wow !

Ken Crocie helped with my 1st Pontiac engine I ever built put together myself.
A long time ago now.
He gave me exact Blueprint machine specs & Assembly Tips.
I forward the Info to my machinist.
He is about 52 now & I am 46.
I can watch him machine all for me side by side.
And I check parts , Measure together with him.
Steve don't mind.
CHECK THAT FOR ME BRIAN ! What does that crank journal measure ?

We are in Farmsville, IL.
Kinda glad.