Help!! Found Gold

Thought I was taking baby steps. After seeing some junk in the oil I tore the motor down and checked the bearings on our first blown small block, Chevy 406ci, 6-71 not stripped, Methanol, 10 to1, 26* total timing, The blower is 17.2% under driven, The barrel valve was at 67% leak and moved it down to 58% for the last two runs trying to put some more heat in the motor.
The motor has 7 -- 1/4 mile passes, 5 ---- 1/8 mile passes or less, but this is were I need help:
#1 main bearing measure .803 top .803 bottom
#2 “ “ “ .803 top .802 bottom
#3 “ “ “ .812 top .847 bottom ******** UGLY, NOT SPUN
#4 “ “ “ .836 top .832 -.837 bottom spun ********* BLACK
#5 thrust do not know how to measure it, looks ok some wear not bad
Rods bearings look ok will mic. Junk did go through them.
One pass with the Trans brake, all the rest foot brake,
Clive77 bearings, are these the wrong bearings?
The Spun bearing? Lack of oil / pressure after the bearing was smashed /spun?
I Need input, we lost our engine builder, (RIP) RICK!
The Oil was changed after every 3starts, was using conventional 10w40
The Last oil change was 2 passes ago and had one warm up at a car show.
No useless gold noticed at that time, but now there is a ton in the pan.
Thanks in advance any and all help needed
hotrod316
Steve M.
PS can you line bore the 400 more than once, (rear main seal). Second can you get a timing chain or gears?

 

I run 10w-40 in my honda accord. It has 341,000 miles on it and it works great. But I wouldn't run anything thinner than straight 50 in my race car-ever. The oil is the cushion the crank and rods run on. The thinner the oil the less the cushion and the more likely you are to hurt bearings. In my TAFC I run straight 50w Lucas when it's cold and straight Lucas 70W with Lucas stabilizer when its above 85 degrees. Dave Gemain

 

I agree. Anything less than 50W is for street driven cars. Is this a dry sump or a wet sump oiling system? How much oil pressure on the last run compared to other runs?

 

THANKS FOR THE INPUT
Oil is Kendal,
Wet oil system,
45 psi at starts
65 psi last time I look at it going down the track
Mains
1 looks very good some polishing
2 looks good some polishing
3 down to the copper not black
4 just the steel backing and black
Thrust looks good some polishing
Sorry can not find the main clearance or remember
Rods all look good, some polishing on the bearings but not to the copper
Rods clearance was .0025-.003”
The biases was a good street motor except for the alcohol
500 hp run 10 seconds
Car run 9.41 139mph
2100lbs race readily with driver
6200 is the rev limiter shift light was 5200 never saw the shift light
Burn out is 4500
No boost gauge plan was 4-5 pounds of boost
Were we way off base? Thanks Steve m.

 

Boost sounds a little low. I'm thinking it was closer to 10PSI than 5PSI.

Oil pressure sounds low. Sounds like the line hone was off too.

Is it carbed or injected?

 

Let me go out on a limb here,

I don't think you are making enough power where the change in oil quality alone may cause these problems.

On the motor it seems the problem gets worse toward the back of the motor...Are you running a stock 400 crank that requires external balancing with an aftermarket flywheel that does not offer it? is the flywheel and converter running true and is the trans in alignment?

I agree completly with everyone that a single wieght oil is the way to go I just think it is possible that you may have another problem. Also most of the guys ( with all due respect to them ) are used to running high horsepower high boost aluminum block engines where heavy oils are required to take up the extra clearance that these engine require in the bearing to allow for the flexing of components that take place in these motors. I can assure you that there are a lot of engine builders that use thin motor oils with minimal pressure to allow for less drag and more horse power on some engines with over 2 hp per cubic inch, granted they are all using synthetic now so the oil can stand the heat generated.

Just another view,

Richard Gavle

 

I have seen promods run on less oil pressure and not hurt anything. Black is def due to a loss of oil, I would check clearances and go from there. I have also seen cars that have good oil pressure up til the end of the run and then they run out of oil due to the engines demand and then its fine again after the run as far as pressure is concerned. How much oil do you run?

 

Thanks again,
It’s injected,
10lbs of boost is more than I expected, I had it way de-tuned at 17.2 underdriven.
Is there a formula to get close for 100extra hp with a 6-71 nonstripped?

The oil pump is a Melling high volume with a Step pan7qt. and one in the filter
Stock crank, BDS crank hub with extra weight, Hays sfi 400 flexplate,
32-3500 stall, converter was shimmed out about ¼”
Good question Trans running true,
Block has x-long dowel pins in it, trans bolts were all tight
How did you check the alignment of the motor and Trans.
Is there a mid point between the motor and trans where the crank would flex more
I.e. number 3 and 4 main?
If the line hone or the alignment was off would the thrust bearing show lots of wear?
Is there TWO problems first, wrong oil, second, something else?
Lost, why are #3 and 4 bearings crushed so bad is it the oil or lack of oil, first, or more boost than I thought and crushed the bearing, something flexing,
Great input
Thanks again just want to look at all possibilities

 

Is it possible that he hammered the motor ?? What did the plugs look like? I usually see #4 hurt before any of the other mains

 

Thanks for the continuous input!
It’s injected
If the line hone was off would the thrust show lots of wear and/or all the bearings?
Checked the main saddles today with a straight edge could NOT get .001 feeler gauge in-between the block and the edge
It’s a Melling high volume pump
It is a 7qt Stef’s pan with 1 in the filter
Stock crank with a BDS crank hub with the extra weight
Hays flexplate with the extra weight
The motor was balanced with all this.
The flywheel and converter running true and is the Trans in alignment?
Great question
Motor has extra long dowel pins for the Trans, converter is shimmed out about1/4”

I do not know how to check the alignment of the two
If the alignment was off would you have a weird vibration?
Would it again shake out all the bearings?
Yes the bearing was down to the steel backing #4
We will change the oil and weight

Is there a mid point between the engine and the Trans where there would be more flex i.e. 3 and 4 main??
1 and 2 mic ok, rods ok
3 main in the block crushed from .802 to .812
3 main in the cap crushed from .802 to 813 not spun
4 main from .802 to .836block
4 cap from .802 to .832 spun
If it was just the oil wouldn’t you think that all the bearings would be bad?
Just trying to understand if the bearings were crushed first from something else or the oil or the oil system failed
Thanks again
Steve m.

 

Mike;

You think it's possible that the crank is flexing enough tortionally to wipe out his main bearings? He's saying it's a 'stock' crank.

The other issue I'm thinking about is that it's a high volume pump. If the pump doesn't have the proper anti-cavitation machining done, it might not be pumping as much oil as it could, and thus starve the bearings or feed them aerated oil.

 

I don't really think this problem is related to the blower. If it was I would expect a rod bearing issue also. The oil weight and amount of oil could be a problem. 7 quarts in the pan isn't near enough. Dave Germain

 

Dave,

That's all I'm running in the BBC... 7 quarts + filter with a Titan pump.

 

Thanks all,
Yes the hole in the block under the rear cap is tapped and plugged.
The more I thing about this too, I think the bearing has been spun for awhile- it is down to the steel backing completely.
I believe it's not the blower as well.
I just need to know how to start eliminating some of the problems (so this doesnt happen again) if possible.
Thanks
PS. Here are some pics, to show what the heck I am spending all my money on

 

I personally try to run more oil rather than less and and heavier oil rather than thinner. I know that this can cause a reduction in horsepower due to the rotating assembly having to whip it's way through the oil. On the other hand I would rather give up some power but keep my engine intact. If a person looks at the oiling diagram for an engine you will see how important lining up the oil holes in the mains with the oil holes in the crank is. A spun main bearing disrupts oiling to more than just that one bearing. I think Hotrod is lucky it didnt take out a rod also. If the initials of your team isn't DSR or JFR any damage can be heart breaking but this could have been much worse. I know that if I was building this motor for myself I would use the Titan pump and try to squeeze another quart into the pan and it wouldn't be anything lighter than 50W in the pan. Dave Germain

 

its starting to sound like that to me too..... sounds like the oil distribution was interupted at the number 4 bearing, then kinda like dominos it affected the oiling to the rest moving foreward....... im thinkin number 4 is the problem, the rest are a result of the oiling getting messed up there.