oscs

iTrader: (19)

What do you mean "work the bearings"

rotary1307cc

iTrader: (5)

Flexes.

800hp not much going on, up around 1k and beyond it beats out the middle three mains.

Nothing catastrophic. All my friends similar HP stock crank motors do the same.

We will find out when u get it apart. If you don't have some sort of catastrophic event happening bet you the middle 3 mains show wear and everything else is perfect

Get it apart and you will know.

Doubt a thrust issue on a clutch car unless you have issues

rotary1307cc

iTrader: (5)

Where you up over 20psi for that event?

What clearance on mains? The more the better it seems to be

Like when I tore mine down 1 and 5 where mint, middle 3 beat up, main caps not moving a bit. Stock bolts even

oscs

iTrader: (19)

Yea 25lbs or so. No clue on the mains Id have to ask.

oscs

iTrader: (19)

I'm pretty sure the flake is from me running the car dry. I don't see a few pulls at 25psi tearing up the mains just yet. We will see soon enough though.

tonypaul

iTrader: (2)

I would pull the turbos apart before I tore the motor apart. You really shoud do both but I would start with the turbos...

oscs

iTrader: (19)

If there wasn't a drop in oil pressure than that would have been the first place I looked.

RonA

iTrader: (1)

So it's the crank flexing not the block? Does this same pattern occur with the stock aluminum blocks at the same hp level?

rotary1307cc

iTrader: (5)

Don't know of the aluminum. I just am talking iron and stock crank. No fretting on the caps from walking. The cranks just starts moving from the ones in have been around including mine, up by and over 1k

I tore mine down down cuz it split a cylinder. But the middle mains where beat to ****, rods and main 1,5 and thrust face perfect

I never saw he said it lost substantial pressure quickly.

oscs

iTrader: (19)

It wasnt "quickly" I noticed it around 10 PSI on the holley after i fried the mechanical oil pressure feed line. I shut it down, got it home filled it with oil. At that point hot idle was down 10-15 PSI

stevieturbo

Are you referencing oil pressure from two different sources when you talk about a mechanical line going to a gauge ?

Or are you always using the logging on the Holley/sensor only ?

oscs

iTrader: (19)

The holley uses a GM sensor in the Factory oil pressure location. The Mechanical Guage reads from above the filter.

stevieturbo

I guess what I'm asking is do both gauges read the same, and do they display the same loss in pressure over time ?

It sounds like one pressure loss was maybe due to damage on the hose to the mechanical gauge only ?

Or are both reading the same, before and now ?

oscs

iTrader: (19)

)
Short answer is yes

oscs

iTrader: (19)

SO all this crank/bearing/rebuild talk has me thinking about upgrading to a forged crank. it seems kind of silly to go in and change bearings and leave a crank that is basically doomed at these HP levels.

With that said i would like recommendations on cranks/bearings/tips and tricks. I will be doing the work myself this time so I'm all ears.

Forcefed86

iTrader: (4)

Didn't you have a few years and a ton of "pulls/passes" on your setup though? Seems odd his went out so quickly.

Not suggesting an aftermarket crank isn’t a good idea, but where does it end? The block isn’t rated for much more than the OEM crank. IMO doing the crank without doing the block seems backward. Judging by your current trap speeds, others seem to make more power at more weight on the OEM cranks without issue. (immediate issue anyway) Not sure how much you plan to turn yours up, but I can’t see the OEM crank strength as the sole reason for the engine making lots of metal at your current weight/power level. I’d pop it open and see what/where the damage is first. Then decide how to “fix” it.

Maybe PM stock48 and ask how his bearings look at his power/weight levels. Seems odd his heavy nova can make tons of mid 8 sec passes at over 160 and not drop oil pressure or beat the bearing out of the motor every few passes. I’m sure there is wear, but obviously not as extreme as what you’re seeing. Wouldn't guess you had have enough miles on your setup yet.

oscs

iTrader: (19)

It looks like you might have missed the part where i melted my mechanical oil pressure gauge feed line and ran the motor down to 9 PSI on the way back to the pits. Im quite certain this is where the carnage stemmed from. As far as max power is concerned, Id have to say that a healthy 1500HP would be nice stopping point. now i suppose the real question is what will the stock block hold? The reports on this website are all over the place. Some say you cant make over 900 without pushing water and then i know a few guys making 1250/1300 at 29PSI and not a drop..

rotary1307cc

iTrader: (5)

Don't decide to do anything until you see what you have first.

rotary1307cc

iTrader: (5)

Yeah mine ran along time, it was beat out good but ran fine, it just lost pressure very slowly over time,

Its not catastrophic, many just put new bearings in seasonally and it is good to go over and over again.

stevieturbo

But when driving surely it wasnt as low as 9psi ? Is that what was logged ?

When my cam bearings walked a few years ago at an event I lost pretty much all oil pressure. I only had a mechanical gauge at the time.

As I reached the finals I raced anyway, probably only had around 2-3psi at idle, rising to maybe 10-15psi at the top end.

I then drove 300 miles home.

Really...all things considered the engine was in very good condition when I pulled it apart. Even the bearings. So I dont see a single low load low psi incident doing much harm if any.

Move forward 3 years with a block with crappy line bore work done. I raced most of last year with poor oil pressure, 40-50psi when coldish, less when warm. Even less when racing/warmest. Probably idled around 10-15psi for most of that year.

When racing and oil was hotter and under more load it really was down as low as 10psi at max rpm/load.

After a year of that plus normal driving in between, the main bearings were fucked. Really fucked. Rod bearings bad, but less so.
Some light piston/bore scuffing but not terrible.

I contribute the damage mainly to the bad machining work for the main caps that was done locally, but also down to the cog drive I had on my blower in 2013 which is bound to have hammered the crank a fair bit and where some of the damage was initiated.

I've a brand new block I'm putting together at the minute, no idea how long it will last..it's all good about from them ******* oil squirters I insisted upon. There really isnt any room for them ! ****.