Reply With QuoteWow can't believe nobody's jumped on this yet!, this ought to be interesting!..
I know there are a few who lurk here that run Blown Alcohol Chevys in Boats and also drag cars. I'd like a little feedback from them on the following questions:
1. Are you having main bearing problems? Ok to tell me all about it, how often changing bearings, what you've found to help/cure problems.
2. What bearings do you use? Kings, Clevlite, etc.
3. Ever try babbitt bearings?
4. How much oil clearance do you run?
5. What oil or additives?
6. Do you run a crankshaft support?
Thanks!
Wow can't believe nobody's jumped on this yet!, this ought to be interesting!..
Motor is almost ready for dyno,
Twin turbo big block chevy on alcohol
I put the motor together with Clevite "H" Bearings Running 3.0--3-5 Over my NA motor witch Im at 2.2--2.7
Going to run 15w40 Kendal oil.
"No synthectic"
Have talked to people that have run a
Molymatrix On yhe cylinder bores but have not seen any HP Increases,Just good ring seal, And oil retention.
And no I will not be running a Crank support.
But will be running a crank mounted Starter
You guys know I ran my blown alky injected deal for 3 seasons. The first season with watered down oil. Copper gaskets.
At least once sometimes twice a week during each season.
Ran Clevite "H" bearings. .0025 when I put it together. Bowtie Gen V block with bolts and no studs. GM Gen V crank
Checked them at the beginning of this year, they looked good so I put it back together and went for it.
Castrol GTX 20W50 oil, an occasional bottle of Prolong and only changed it once and maybe twice during each season.
Ran a Wix filter and changed them fairly reguarly to cut them open.
If I ran .0025 clearance in the car, I'd kill the mains in a couple runs. Been there. For the boat, I don't know. It's a .0035 currently. I do know I have better life on the mains in all the boat motors. Prolong is interesting. Somehow the boats seems easier on the main bearings.
Where I am going with this is an old problem has resurfaced. We have fought a rather mysterious main bearing failure problem that randomly happens on the car motors. When we think we have it licked, we find out we don't. Bakersfield race (drag car) we spun #2 main. Just looked at the mains before the race (30 passes or so), all was fine. Lost it on the first run. Would not have known if we didn't know the car and the tune up so well. Run was 1/10 off what it should be. Filter was clean. Oil pressure after run down 10 lbs from the norm. Mark 4 tall deck, Eagle 4340 crank. This was a friends motor and drag car.
When we got home, I pulled the Fiat motor apart to check out. To my surprise #3 main had touched and shrunk. Not spun yet. P&S block with priority oiling and Cola 4340 crank and only 8 runs on this motor.
I'm trying not to be so windy here, but now we have seen this problem with 2 different block oiling systems, had it happen with Chevy, Cola, Eagle, and other cranks. This is the only problem the motors have. No backsided pistons, rod bearings like new, no oil dilution. We might go 50 runs, the bearings look good, next pass we lose it. Or even had one motor go 200 runs. Then suddenly we lose the mains on the next run. :yuk:
Prolong is interesting.
When you put it in an engine you really do not know if it is doing anything.
Put in an outdrive and it shifts like butter the first shift. Runs way cooler also. Made a believer out of me.
Have it in the outdrive behind the quad rotor boat, Stock bravo lasted all year. Ran the piss out of it Tues evening and the drive was cool to the touch. Way over HP'd and RPM also.
Ran it in my Alpha SS drive for 8 years behind a blown small block. Drive still running good to this day.
Have been putting it in engines since the outdrive experience.
Maybe you should try it? Can't hurt.
hey fiat 48 i have run clevite h bgs for 4-5 yars never had a problem with them coming lose in the journals i always use 50wt valvoline racing and a wix carquest racing filter the number is 185060 at carquest, the regular chev filter is a 85060, i ahve run that one and then switch to the racing filter is brought the oil pres up 10 more lbs by using the racing filter, i change my oil every month just for saftey precautions, i own a carquest auto parts store so the oil and filters are very easy access, also we have a machine shop so we play with alot of race motors which give us alot of info on bgs anyway i run blown bbc on alcohol with inj anyway if i can help anyway let me know.
laterwrap your ass in fiberglass:wink:
Sounds like from all the replies this is more of an application problem and car related. Perhaps the burnouts, tire shake or bite down after the burnout whips the crank enough to touch a bearing sometimes. Maybe it just comes with the territory. May be time to take some stroke out of the car stuff.
Originally posted by Fiat48
or bite down after the burnout whips the crank enough to touch a bearing sometimes.
You could be on to something here. I would think a difference in the burnout would be noticeable though.
Is this race track specific or track condition specific? Do you snap the throttle shut following a burnout?
Well, we try to get out of the throttle on the burnout before the tires bite down and shakes the drivetrain (and crank) to death. We have looked at the mains after severe tire shake and not caught one spun. Each track is different. And being a short wheelbase altered we sometimes have to "pedal" the car to get it to go straight. I'm sure all this whips the crank.
Feedback I am getting from other car racers is they are running real wide main bearing clearance like .005. So far, the boat guys don't seem to have this problem.
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