cam bearing failure

[beebemotorsports]

what makes 3 cam bearing get wiped out

small block 408

about 6 dyno pulls

drove it in to tha autorama and out

and drove it sat for about 10 miles

and drove it sun for about 3 miles then heared a knocking noise and i look down at the oil presure gauge and it read 0 so i shut it down and towed it home.

rods and mains look ok

the 3 inner cam bearings are all gulled up

[ProGSX]

Not enough clearance?

[Jay Allen]

Sounds initially like an oiling issue.

What bearing did you use?
Was the cam new?
Was the block fresh?
What was the spring pressures used?
Did you actually measure the springs?
What style of cam is it?

I'm fishing here.......

[85Camaro]

It was the 3 center brearings that went


Cam was new

block was used before in another of there cars but was freshend up all new bearings

Comp cams Solid roller

he will have fill you in on the rest

[beebemotorsports]

i was not the builder but this is what i know

What bearing did you use? It was a coated bearing
Was the cam new? yes comp cam custom grind
Was the block fresh? it was fresh we use to run that block in or nova with no problems
What was the spring pressures used? witing on an answer from builder
Did you actually measure the springs? yes he did
What style of cam is it? solid roller

[Jay Allen]

Not enough oil in the cam tunnel. (Do you Evac on the engine?)
Not enough clearance with the coated bearing.
The cam was bent.
Excessive (way excessive) spring pressure.

***These are just guesses.

[beebemotorsports]

no there is no Evac just 2 valve cover breathers

thanks

i know its had to tell

[Jay Allen]

I just had a flash of brilliance.

Is this a small base circle cam?

[85Camaro]

I think it is a small base cir, It's .630+ lift with a 1.5 ratio and a 3.75 stock and the rods did not need to be clearenced by the looks of them.

[Chris Uratchko]

I have not done this for years.... but, I am almost certain you can get a roller bearing for a stock journal camshaft. This way you'll only hae to bore the tunnel 'slightly'... and it will not compromise the main oiling grooves behind the bearings.

Did the builder set the cam up on some v blocks to make sure it is not bent? I N-E-V-E-R trust a camshaft after its been shipped. Always set it up on v-blocks to make sure it's straight with an indicator....

I've seen everyhing you can imagine get destroyed by the ups guy.... for all you know they were using the cam package to beat on something with....

[Jay Allen]

I've seen everyhing you can imagine get destroyed by the ups guy
This is why I have been know to drive for 2.5 HOURS to deliver a camshaft. Some things just aren't worth the risk.

If it is a reduced base circle cam, I am betting it is bent. That is why it ran for a while and then went to hell in a hand basket. Being bent that is.

[85Camaro]

This is why I have been know to drive for 2.5 HOURS to deliver a camshaft. Some things just aren't worth the risk.

If it is a reduced base circle cam, I am betting it is bent. That is why it ran for a while and then went to hell in a hand basket. Being bent that is.

I was kind of thinking the same thing when I seen 3 bearing (2,3 and 4) wiped,

Like as if those 3 where fighting each other, 1 bearing spun would be different but those 3 where trashed and the 2 ends where hardly touched... and they had no problem with that block in the Nova at all with cam bearings....

[beebemotorsports]

don't know what to do now

what do you think about putting ne cam bearing in and if the press in ok then get a new cam and try it.

or bore the cam tunnel and get a new cam with roller bearings ?

[beebemotorsports]

yes it is a small base circle cam

[85Camaro]

I would check the cam 1st see what you find before you worry about the block if the cam is bent you know what caused it. then the only thing to wory about is did the block get damaged??? if the cam is not bent then it would be a good Idea to have the came tunnel bored

[Chris Uratchko]

Well I can imagine the journals are burned up on the 3 center? Put a v-block under the 2nd and 4th journals, and spin the cam with an indicator on 1 or 5 and see wat it does.... or, v-block the ends and check the center 3.

As for new std. bearings in the block, if it's been spun I doubt you can save the bore.... you need at least .002 press.

This is a 400 block? Did you guys put some hp to it prior to this happening? Don't rule out the block moving around......

[85Camaro]

Yes 400 block, The block has been 9.20's in a 3500lb race weight car with 325-350hp of nitrous put through it.

[Chris Uratchko]

Well I know everyone has financial constraints but them 400 blocks are like a red headed step child!!!!!!!

[85Camaro]

Or like a box of chocolates!!!!!:-D

[Nosman]

For what it's worth, one of our guys had a fresh
Big M block with the coated cam bearings from Dart, and he took out the middle bearings as well. Went back to a standard non coated bearing and all is good. Had a big roller with big pressures but it's good with the standard bearing.

[Chris Uratchko]

Well lets not start considering it's the coating bearing doing that. I have run 2 engines with 1180+ pounds of spring and high rpm with stock cam journals, and dart coated springs and all season long at the end, they still looked like new....

Granted, I was worried as heck the whole season but pleasantly surprised upon teardown.

[Nosman]

Ya I'd hate to think it was just the bearings. He had the cam tunnel opened up slightly and a set of standard Durabond bearings in stalled and everythings good.

[Tom McDunnah]

Sounds to me like an oiling problem you had,or incorect installation of the #2 #3 #4 cam bearings, improper clearance,thats where I'd be looking

Oh and another thing,If you want to check the camshaft for run-out,an easy way is to use a piece of angle iron 30 inches long in a vise and a magnetic dial indicator will do that job,hope you get it figured out

Tom

[beebemotorsports]

checked the cam for straight (s eems to check ok
i bought a new set of dura bond non coated bearings and miked the OD

and miked a set of ones that where installed in a motor but never ran and then pulled out they where .002 smaller OD

we hammered in the set that where .002 smaller then new ( sowe didn't ruin a good set) just to see what would happen
they seem to go in ( you can't push them in by hand) but a couple of taps with the hammer and it is in.

so the new ones that are .002 bigger should be a .002 press fit and be ok

so i have no choice Money wise but to try the new set of bearings and a new cam .

[Chris Uratchko]

Keep us posted!

[beebemotorsports]

chris
i tried calling you last night

[Tom McDunnah]

Ok I got a question,are you running the oil restrictors in the back of the block?? If you are that may have caused the problem.

[beebemotorsports]

Ok I got a question,are you running the oil restrictors in the back of the block?? If you are that may have caused the problem.

no oil restrictors
good thought thu

[Chris Uratchko]

chris
i tried calling you last night


Yeah, I got your message the next day.... sorry bout' that.


As for the restrictors.... they only control lifter galleys. The main oil galley that feeds the mains, and rods, feeds the cam first..... so for the cam to be starved for oil, so would the mains have to be....

If anything, the restrictors would help the cam bearings get oil.

[tom_cowle]

It funny somebody mentioned UPS as the culprit, a few years ago I had a chance to tag along for the big UPS "We don't know what it is" sale that UPS had. Its a sale where they take everything that wasn't claimed or fell out of the box or whatever. UPS tags the product by a person who guesses what the item is by quickly looking at it and accessing the product.

Its a massive sale and there are several auctioneers selling all at the same time, but when I was there I saw a Liberty pro-stock tranny listed as "Item: Gear reduction device, Application: farm or industrial use" a new in box PSI topfuel blower listed as "Item: Fluid pump, Application: industrial"

I also saw a Kryptonite crank box literally folded in half and the crank inside was folded in half as well. I saw several camshafts that were either bent, broken or badly rusted and the lot of them sold as "Item: Camshafts, Application: Door stop or pry bar"

I just sent two cams out to Camaro Dave this week, I hope the delivery guy takes care of them for me, I doubled them up and boxed them again. (Dave if your reading this).

Tom Cowle

[396chevelle]

If the cam was bent severely enough to wear bearings this badly wouldn't it be difficult to install? The engine assembler should have picked up on this.

[Chris Uratchko]

Yeah it would have had tight spots upon rotation...... though, I'm sure some folks might just figger it'll wear in... ???

[beebemotorsports]

the engine builder said it spun fine and had no reason to think the was a problem

[Chris Uratchko]

Just chalk it up to be just one of those things.... 'stuff happens'...

[beebemotorsports]

we are puting in the new cam bearing tonight and the new cam will be here tomarow
so by tuesday or wed we should be able to start putting in the motor
hopefully it will work out

if not we will just have to get some more parts for 85camaro's motor so i can use it

[85Camaro]

if not we will just have to get some more parts for 85camaro's motor so I can use it

I'm starting to think that is your whole plan!!! You wouldn't be able to handle having the worlds fastest 68 chevelle!!!!!:lol:

I'm giving you 1 more week to get that chevelle going then it's on to my car,:lol: If doesn't run in 1 week from friday I know a guy who likes 68 chevelles and would take it in trade for some engine labor!!!;)

[Chris Uratchko]

LOL.... personally, I like option 2... in both cases.

[Jay Allen]

Sorry I have been gone. Extremely busy.

I am very interested to see what actually ends up being the culprit. But with a sm base circle cam, a teeny tiny amount of flex (and they do flex) with a teeny tiny amount of bend, and you are in trouble. The engine assembler would NOT be able to see this. It needs to be put in a fixture and checked.

I do not believe it to be the bearing.

Keep us posted please.......

[Jay Allen]

Sorry I have been gone. Extremely busy.

I am very interested to see what actually ends up being the culprit. But with a sm base circle cam, a teeny tiny amount of flex (and they do flex) with a teeny tiny amount of bend, and you are in trouble. The engine assembler would NOT be able to see this. It needs to be put in a fixture and checked.

I do not believe it to be the bearing.

Keep us posted please.......

[Monty Mikho]

Beebe, put the cylinder heads and caps on the motor and torque them all down. Check if the cam still spins..

[Chris Uratchko]

Good one Monty!

[beebemotorsports]

we are assembly the motor this weekend
we will torq it down and see what happens

comp cams wants me to send the old one back and look at it