Rear main issues

1st weekend out after 3rd 250' pass spun #5 rear main. Repaired crank and put new saddle in, lined honed, etc.....
2nd weekend out after 4th pass checked rear main and its chewed up again, luckily not bad enough to damage crank.

526 KB-10 Fuel heads, Whipple, 3disk Crowerglide, 8300rpms tops every pass.
King bearings, 60 weight Brad Penn, 13 quarts, wet sump, Faria pump, Nitro system one filter

Question, what do I need to do to stop this, is the clutch transfering heat to the crank and causing this?

Same setup I ran for years except for KB block (TFX billet prior) and turning more RPMs now.

Thoughts??

 

how many quarts of oil? wet sump or dry sump?

 

13 quarts, Faria wet sump, Nitro system one filter, Olson pan. Around 120# oil psi.

 

How old is the clutch itself? Any aluminum?

 

All aluminum with a farely new donut and flywheel (year or so) w/ ring gear, 6 stand.
Serviced before both races.

 

When you changed blocks did you recheck alignment of the block and bell housing/gearbox. We clock our crank flange to the bell housing and have all our gear as close to zero run out. you may need to make offset dowels etc to correct a problem. I have seen cars with 30th+ run out that would tear the rear main to pieces evey run

Clarky

 

Never checked that, whats the best way?

 

Go here for simple complete instructions on doing it right.

http://www.lakewoodindustries.com/pdf/BELLHOUSINGALIGN.pdf

Go here for recomended optional Lakewood products.

http://www.lakewoodindustries.com/pdf/OptHAYS_LAK.pdf

Go here for for Lakewood Dealers to get your Bell Housing line up kit.

http://www.lakewoodindustries.com/DealerLookup.aspx?CountryID=36

 

You need more oil; at least 3 more quarts. Borrow someones 3quart Accusump plumb it in and see if that doesn't solve the problem.

 

We just recovered from this issue that seems to run around the pits like the flu. If you are running an aluminum flywheel it could be flexing at the crank hub. Our lightweight titanium unit was. The flywheel goes into oscillation and tears the rear main out. Mike Pavia made us a ring that attaches to the back of the motorplate that limits the flywheel movement and keeps it from going crazy and taking out rear mains.

Our problem was happening at 10,400 RPM and, although you are not seeing that number, flexing of the aluminum flywheel may be your problem. Fuel cars have tabs on the back of their flywheels that contact their 4130 steel motorplates. Mike Pavia's ring attached to your aluminum motorplate and is pre machined to give you about .070" clearance between it and the back of the flywheel. We got a new heavier titanium flywheel from Crower, installed the ring and haven't lost a rear main since. And yes, the flywheel definiately hits the ring.

First round at Vegas Daniel hit the rev limiter which normally spelled disaster. But not any more.

Mike Pavia is on ITA.

RG

.

 

Thanks guys for your help. Looking into all your suggestions as we speak.

 

is the problem solved

did you ever solve the problem we are having the same problem after two runs tried to spin bearing good oil pressure titanium can with brad 5 with crower clutch alll bearings look good but rear main is trashed
thanks
sammy

 

Rear main

Sent flywheel and complete clutch to Crowerglide. Flywheel was bent .010
Crower trashes them when they get .003 out. Rockwell was also gone on it.
Purchased new flywheel and had everything else freshened. Knock on wood, about 16 passes later rear main still looks good. We did do the extra #6 oil line to rear main, knotched cap, etc.
Thanks to all the guys who commented and a special thanks to Mike Canter for his time.

 

After 3 saddles and cranks later we finally cured our rear main eating gremlin
so i can feel for you
I know what it is like to have this problem
we still check it every couple passes for grins

 

Randy, do you have any rub buttons pressed into the backside of your flywheel (ie: .070" clear to the buttons), or does the ring just sit flat and parallel to the flat backside of the flywheel? Have you seen any witness marks yet at .070"? Thanks.

 

We use a .375 motorplate and .225 deep flywheel it hits the motorplate real hard at .050 clearance.


We think this happens because the crankshaft (tips or flexes) at #5 opposite the 7/8 rod throw. just look at where your flywheel is rubbing. its always opposite the throw on the crank. Just my 2 cents.

Mark

 

Mark, thanks for posting this.

Is the rubbing you are seeing opposite the 5 throw, or opposite the 7 throw? Do you see the rubbing "move around much" in in terms of the clocking versus the 5 or 7 throw, or is it always pretty constant in the same location?

If pretty constant, then I'd tend to agree that it could well be a crank phenomenon, as opposed to just a randomly oscillating/flexing clutch. If it was a clutch phenomenon, then I would expect contact all around the potential ring of contact at various times.

An old timer ex GM Powertrain engineer recently recounted to me his BB laser/strobe testing sessions involving crank flex in AL road race blocks. He had exactly the same sorts of comments/observations regarding flex about the 5 throw. Interesting!....

Thanks.

 

Rear main oiling

TFX's engine shop recommends a separate -8 oil line going to the ream main. That wouldn't be a bad idea for any other KB/Brad engine that has that option. Besides it's normal loading from the 7/8 rods, the rear main takes a whole lot of abuse from the clutch/misalignment and the additional loading that these cause.

Works in nitro service and we have a whole different set of abuses goins on in our motors.

 

bearings

get away from king bearings they are junk go to clevite im running on the same bearings from two seasons ago go out almost every other weekend run 3.80's and turn it 9200