It seems that detonation is a big problem with new motors, is it beacuse of the timing? If thats the case is there a best way to set the timing? Just asking because I have lost two new motors, one to detonation and possibly the second one.

 

I agree... For me it was timing...bought my car with a rebuilt 455 that was damaged in the bottom end by detonation..The guy had stuck a HEI Dist in it and didnt bother to curve it to the engine...just ran it... I ordered a DUI unit build to the vehicle and engine specs and rebuilt the engine again...L2323f pistons..low end torque cam...Problems solved..runs great

From what I am reading it looks like a lot of issues with HEI units just being thrown in and run as is...that is just one of the problem areas...

 

I also set up the carb (edelbrock) with an A/F ratio guage..no guesswork...

 

What gauge did you use? I want to do the same thing to mine but I don't want a gaudy pod in my interior...

 

I can't believe that no material showed up in the filter(s). That much damage has to go SOMEWHERE. Looks to me like oil starvation and or too tight bearing clearances., possible bent crank. The reason the oil press wasn't too bad, the rod bearings were piggy backed, thus taking up some clearance. Those rods are shot. The mating surfaces don't even look like they lay flat, on the side to side clearance.
Those cylinder walls look glazed from the pics.....what grit did they hone them with?

 

It knocked so I doubt they piggy backed. Starvation would have showed up long before this, especially on a dyno.

280 grit, plateau honed with a torque plate, moly top ring, .022 end gap. It ran rich for awhile at idle, that will glaze the cylinders much more quickly.

 

I had one piggy back like that 14 years ago. Had a knock. I pulled the cap off and the bearings were on top of each other.

 

I think gas is getting crappier every day

They know all the new junk is FI with auto spark retard....

So there's more $$$ in it for em to LIE about the quality of the fuel...

Must be why my whiz bang 6.0 liter LS motor in the truck gets 12 mpg on the crap I get around here and 14-15 on NO ETHANOL gas I've ran in it

 

AEM...cut a hole in the exhaust pipe below the manifold for the AF sensor and taped the gauage up the door onto the dash ...not ideal but it worked...once its was set I put a put a plug in the sensor fitting...

 

just an idea on this, with it being shipped from US to sweden could maybe something got jostled in the move? I know i had a Computer shipped from Ohio to Mississippi and it was F&^%ed when it got there.

Forget i said anything didnt notice there was 3 pages and only read the 1st page lol

 

I dont know what you people mean with "piggy back"my english is not that good,but the bearing sell were in top of eachother on the rod that was gone,and the sound was actually the piston hitting the head,not the valves but the portion of the head behind the combustion chamber wich is flat,talk about high compression The guy at the machine shop who looked at my crank rods and pistons said also that it could be oil starvation or something wrong with the clearances but not 100%sure he couldnt see any detonation marks.I have to mention that the only time i pressed the car a bit was a few months ago when i met a C4 vette at the stoplight ,Guy looked at us (4people in the cutlass) and asked if my "Chevelle" runs good oboy i didnt know if i should be mad or lough at him ,anyway we just floored it both when the light went green and quite honestly i didnt expekt much due the fact the c4 is made of plast and we were 4 in my car,lets face it the c4 is a quite fast thing,well with not much time to look at him i only looked at my gauges and let go at about 5200rpm just before limiter kicks in,i was actually more surprised than him to see the vette was about 1 1/2 cars behind us!
That was actually the only time i revved the motor at that rpm for lets say more than 10-15 sec. but i mean shouldnt they hold up? are olds engines that sensitive?

 

You guys have scared the crap out of me......I'm running 36deg total timing in my 455 with a stock replacement style HEI. One previous piston failure (1,500 miles) due to excessive rod bearing clearance, and another piston failure (1,300 miles) due to what I believe was too little end gap on the rings.

But now I'm wondering if the common factor in these problems is excessive timing with this HEI?? I probably have 4-5k miles on this combo currently.

 

What do the main bearings look like? ..........................
Ill bet #2&#4 are wiped....

 

Almost all of them were wiped,whats special with 2 and 4?
pic1 is nr1 and so on.

 

After two engine failures of my own and having seen some locally and on this site if my new engine goes thats it for an Olds engine in my cars...I dont know how many competent machine shops are out there any more that can handle Olds properly or that have enough attention to detail to do it right...And it dont think its just Olds that suffers from a lack of quality workmanship...

A new crate engine and EFI will be my next choice sadly if I end up down that road

 

2&4 are usually the first ones to go. The crank tends to bend like a fishing rod under load since the thrust bearing is in the center. The rotating assemblies are heavy, and the blocks aren't especially thick.

A different make engine with high horsepower would flex in a different spot and wipe out different mains first. But Olds, just tends to be 2&4 when the crap hits the fan.

Don't be confused, I'm not saying Olds motors are junk, Just pointing out the weak points. Steve-o a few posts back has a stock 72 block with 800+hp that hasn't folded in half yet.

 

Almost looks like antifreeze damage to me......
Did u ever get coolant into the oil?

 

Panos said:

"I dont know what you people mean with "piggy back"my english is not that good,but the bearing sell were in top of eachother on the rod that was gone,and the sound was actually the piston hitting the head,not the valves but the portion of the head behind the combustion chamber wich is flat,talk about high compression The guy at the machine shop who looked at my crank rods and pistons said also that it could be oil starvation or something wrong with the clearances but not 100%sure he couldnt see any detonation marks."

 

I'm having a hard time swallowing this 6 second detonation bearing swap story.

My little 355 makes right at 390HP at the flywheel and I add 200 more horsepower with nitrous and never had any rod bearings or main bearings spin.

I pulled my engine recently because I thought I spun a rod bearing, turned out to be the aluminum in the passengers side head rattling around in the heat crossover in the heads I ported about 3 years ago. The shortblock has been together for over 20 years since I last freshed it up and it has over 60,000 miles it. More than 500 1/4 mile runs and more than 200 of those 500 runs was with nitrous.

My bearings still look good, not new but I wouldn't be afraid to reuse them and they would probably last another 20 years if I didn't race anymore.

Sounds like to me like you need to learn to build your engine yourself. I wouldn't had to pull my engine if I filled the crossover passages in my heads myself instead of having a so called professional do it for me.

I don't like playing with hot molten metals and that is the only reason I had someone else do it for me, this time around I'm putting cast iron plugs in the heads and then I'm going to weld the **** in there.

You know the old saying, if you want something done right, do it yourself.

 

ah64pilot, I was refering to all the talk about total timing numbers compared to mine that was making me nervous. The first problem my engine had was the piston smacking the head, and we found the #8 rod bearing had excessive clearance. It was sent to a builder to find the cause (which he couldn't), was rebuilt and dyno tuned and sent back. Another 1,300 miles later the #8 piston failed at a high RPM. The #8 rod bearing had absolutly no bearing damage. During tear down inspection I found that the builder did not have enough end gap on any of the piston rings (IIRC 0.014-0.016?) and all 8 piston to cylinder walls were tight (0.002-0.0025). I had the cylinders brought out to 0.003 and gapped the new rings according to what Mondello suggests in his book.

What was making me nervous is all the talk of these rod bearings being so sensitive to detination (which may or may not have been the cause of both failures). Both failures were expensive, and I don't want to head down that road again if it's as simple as too much timing.

 

The 6 seconds was a dyno pull, the bearings didn't sawp then, but they showed clear signs of detonation.
You bearings are fine because you're obviously not experiencing any running issues. Advance the timing a few degrees with the nitrous and see what happens then advance it some more. I promise you when it fails it will fail quickly.

Someone is still going to have to explain the starvation theory when only one spun. But I learned something here as well. No more stock rods in anything making this much power.

 

SBOrule...glad to hear your engine has lasted so long...You are correct about one thing...if you want something done right...do it yourself (applys to some people anyway)....

 

Detonation caused the mains to wipe?
How many times do ALL the rod bearings spin?
Sorry, I dont buy it

 

I pulled apart a 455 that had the front 4 rods spun badly and 2 mains as well. Now that's oil starvation. Then it generates heat which makes them lock up. Oil is not only for lubrication but at the same time it keeps the bearings cool.

 

Ask any reputable engine builder, it happens.

 

What CAUSED the bearing(s) to SPIN in the first place?
If after they spin it's the HEAT, why did they spin in the first place?
I can see a Main spinning because of the oil hole no longer matching up with the oil feed hole, but the rods don't care.

Improper bearing crush (spongy bolts maybe) or too tight of clearances(thus not allowing enough FLOW of oil to REMOVE heat) seems like the logical cause

If detonation causes bearing failure, then how can diesel engines survive with those shock loads each power stroke? I know lower RPM. But instantanious psi on bearings are high. How about the 350 DX? How'd their bearings survive from the "detonation" of diesel combustion?

 

if this really was caused by detonation, then it doesn't matter how beefy the rods were, it would have still beaten the bearings to death.

 

I agree. And I think cutlassefi has done the right thing by coming in here and stepping up and doing what he can to figure out what has happened and try to take care of it thousands of miles away.

 

Correct.A stiffer rod would have been worse,putting even more abuse to the bearing.That is what I mentioned with titanium rods.

 

Don't confuse powerful but correct combustion with wanting to beat the piston back the other way, at the wrong time, big difference.
And once you start beating on it then yes you will lose crush then consequently the ability to hold the bearing in it's place. Then a gap forms between the shell and the rod, then guess what, there goes part of your ability to dissipate the heat. Go to the Federal Mogul website, they have pix of detonated bearings. That's exactly what I saw when I pulled the dyno bearings out.



And thank you Bill.

 

All the rod bearings spun ?

Holy Shyt, sounds like it was something other than detonation from low octane gasoline to me Mr. Cutlass EFI.

I have heard my engine detonating more than a few times over the years when using nitrous with only 93 octane gas and too much timing and never I never spun a bearing.

You mention Federal Mogul, in the future I would recommend Clevite 77 bearings, if not.

I'll have to read this topic over again, I don't recall the guy saying anything about racing his car or mentioning any detonation issues.

I'm thinking the rebuilt stock rods big end weren't completely round and when you installed the bearings and torqued down the rods, there wasn't enough bearing clearance and wipeola, bye, bye rod berings.

You guys you have Big Blocks and you sbo guys too, should really invest in an Accusump system, having the extra oil to lubricate the engine when pressure drops below 25psi is down right cheap insurance plus, you can pre-lube your engine before you even crank it, to start the engine. Oldsmobile's have a poor oil system to begin with and regardless if you have a 7 or 8 quart pan, it can still go dry enough to cause oil pressure fluctuations from lack of oil. Oldsmobile engine are also acceptable to bearing scuffing from dry start up issues. If your car sits alot and isn't driven every few days. prelubing your engine before start up will add years of life to your bearings and other moving parts in your engine.

Brain 507olds can probably help this guy get in touch with Hank over there in Sweden, then Hank can atleast tell this guy what machinist not to take his Oldsmobile part to for machine work over there, he sure has had his share of bad luck with machinist over there.

 

Very interested in this topic, as lets face it there is many who have had issues with newly built BBO. Mines still being built but I'm leary.
Is detonation more of a risk with a certain cam style? Due to cylinder pressure? Or is it more of a risk due to the common Olds engine "loose"
crank clearance?
Seems there are at least a few guys on here that support the possibility of engine damage due to detonation.
Water injection a good idea? I sure don't trust every tank of gas I get.
Of course after proper machine work and clearance next would be proper tune.
Could there be a bad batch of bearings?
O.K. thats all the questions I could find floating around my head (for now)

 

I admire an engine builder that claims his mistakes and helps trouble shoot things when they go wrong. I down right LOVE an engine builder that take broke sh*t back and fixes it lol! Just kidding you EFI...

Jokes aside, this really could be detonation. I was skeptical at first but I think back to my first BBO 15 years ago. I rattled my way down the highway never knowing any different...I knew it wasn't good, but hell, the car ran better down the track. It lasted all of 3 years with mostly city driving. It was a much lesser build than this, but it too succumbed to detonation. I had a spun #1 rod bearing. In fact, it is the motor Nicken's just built for my resto

 

O.K. for the record for the last time,

Not all the bearings spun, just #6 rod bearing. The rods were reconditioned with new ARP bolts. Clevite bearings were used throughout. It had right around .018 side clearence and .0025 bearing clearance on the rods and .003+ on the mains. Thrust was .005-.006. Block was studded and strapped. Pistons are SRP 4032 material, moly top ring at .022 end gap.
Compression was close to 11.0:1 with C heads. Yes the cam can effect cylinder pressure therefore effecting resistance to detonation.

 

So what were the clearance specs of the engine?

 

I will take this to PMs with SBO Rules.

 

Some people

This guy is all upset because I asked him to describe himself when he was trying to act like he's knows everything and he hasn't ever built anything in his life, he pays others to do everything for him.

He deletes/edits his messages when he's caught lying.

Stop sending me PM's 380 racer, if you got something to say to me say it publicly or better yet, say it to my face.

 

cutlassefi

Where are you located in Central Florida.

Got any pictures of your car.

Do you or have you ever raced an Oldsmobile?

I have lived in the Orlando area most my life, pretty much know everybody who's anybody and the only Mark I know that's a salesman/engine builder doesn't own an Oldsmobile anymore.

 

I don't understand why this thread has become so hostile...it never needed to be. I may not believe that detonation caused this engine to fail, but I don't need to go about picking a fight with someone I don't even know. There has got to be a way to keep this discussion civil.

SBO, you have valid points. But name calling and hostility undermine the validity of your argument. There are 3 instances in this thread in which CutlassEFI has edited his posts:

Last edited by cutlassefi; August 13th, 2011 at 02:05 PM.
Last edited by cutlassefi; August 22nd, 2011 at 07:49 AM.
Last edited by cutlassefi; August 23rd, 2011 at 07:10 AM.

In all three instances, his edits were done BEFORE the next post in the thread. I don't believe his intent was to cover his a$$, no one had the chance to call BS before he edited his post. I understand that he edited them to make sure his facts were correct. And to be honest, there was no reason for him to cover his a$$ until you posted in the thread. Draw your own conclusion as to the quality of his work, but being a jerk on this message board is unnecessary.

 

Please people lets keep it civilized,if anyone should be upset right now thats me.We
can all assume at this point as what happend to my engine and whos fault it is or not.Right now im willing to rebuild the engine and throw even more money to it (sold my daily driver last weekend and have to borrow wifes car to work)but i have problem with shipping the crank due to its weight,if someone can help out with shipping a crank to Sweden i would really appreciate it,already talked to Mark and John here in the forum and they try to find out how much that would be,but if someone else thinks he can help me out with that,you re more than welcome to do so.