Looks like cam gear keyway issues paging kevinb

Here are a couple I pinned together for a different reason (to drive my fuel pump off front of cam) but you can get the general idea. Also a pic of the camshaft keyway as designed. I think you can see where the problem is when using stiffer valve springs or more rpm than originally intended. Im really not sure how the nascar croud got by with this design. Mike:cool:
 

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How much valve spring pressures are you running?

Seat?

Open?

Anybody double key their cam and gear?
 
BlownV6 said:
If your asking me , I run 450 on the seat and about 1050 open. Mike:cool:
Click to expand...


:eek:


I was asking the OP..... because he sheared his key off..... if we assume it was possible it was tight...... the resistance had to come from somewhere..... either valve springs..... oil pump..... or something driven off the cam...... My point was...... there probably comes a point..... when the resistance gets high enough..... that you will have to step up to a two keyway cam/gear setup..... or dowled setup.
 
I would say that if the front bolt is say 70 ftlbs or more the chances of this happening are cut down considerably!! However this has happened to a number of accomplished engine assemblers who swear that bolt was tight!! It could come dowm to simple harmonics of the situation as used. Mike:cool:
 
I've had this happen to me once as well on a Weber billet kit. And... I've also had the bolt head shear off at 70ft./lbs. using moly. I believe the install instructions now say to use oil...


K.
 
NCTURBOS said:
I've had this happen to me once as well on a Weber billet kit. And... I've also had the bolt head shear off at 70ft./lbs. using moly. I believe the install instructions now say to use oil...


K.
Click to expand...

Was yours an arp bolt? Mine is an arp with a pretty big head. Think it uses like 16mm or similiar size.
 
Blazer406 said:
How much valve spring pressures are you running?

Seat?

Open?

Anybody double key their cam and gear?
Click to expand...

Im guessing 200 seat and 400 or so open.The Heads came from Excessive Acceleration
Just in case someone is searching this thread in the future
I was in a water box on a new engine had only 3 easy passes on it
The track never watered the box so i had to put my foot in pretty good to get the tires started .when i came forward I was higher in the RPM range than normal and the car grabbed hard.
Went to the line and 2100 RPMs is all it would do
It didnt have enough power to get it on the 2 step
No matter what it wouldnt go above 2100. I thought I broke the converter
It would build boost going down the track and ran desent at higher RPMs
The tune was off ,Got alot of knock even Idling,hard to start,no power.
I Changed every part twice and checked reluctor ring slip,Cam sensor retainer.
Id wake up in the middle of the nite and think of something go to the garage and check.
Compression was okay not great but consistant
Smoked the whole intake with a smoke machine.Checked for a clogged muffler.I got real lucky I didnt tear everything up from rods to cam to valves.So far everything looks good
Dont really know what Im doing with the car next season but ill be happy to be back in the seat
 
Bob,

I had this happen a few years ago at BPG........it took me awhile to figure it out too!!. My failure tore up the keyway in the cam. No bent valves, but ran like crap and wouldn't get out of its own way.

Are you using a hardened key? If you're not sure, take a file to one.....if you can file material off, its soft. You might consider a hardened piece in place of the softer keys. I couldn't find a hard key in the right size. I had to make a hardened key out of a thicker one.......ground it to size on a surface grinder. I like Mike's idea about pinning the gears together too.
 
Is this crap starting again?
Aluminum spacers?
Soft woodruff jeys?
Get a Steel spacer made to replace the crappy Aluminum one.
Get a good,hardened key - IIRC crank keys were the prefered item when this happened years ago.
Get Mike to pin the ass'y.
Grab the idiot by the throat who sold you that setup and throttle him.
How stupid can they be?
 
Grab the idiot by the throat who sold you that setup and throttle him.
How stupid can they be?
Click to expand...

Careful!!!! Some very reputable engine builders use and still sell aluminum spacers!!!

I'll not be using aluminum spacer in my engines, I'm just sayin.
 
After talking to some local folks.
Im getting a steel spacer and new keys spacer and bolts from TA
Also looking into cutting the cam all the way back with a hardened hex key
Mike if you could PM me?ill call you got a couple questions off board
 
BobbyBuick said:
After talking to some local folks.
Im getting a steel spacer and new keys spacer and bolts from TA
Also looking into cutting the cam all the way back with a hardened hex key
Mike if you could PM me?ill call you got a couple questions off board
Click to expand...

Bobby , sent you the PM Mike:cool:
 
KevinB said:
Was yours an arp bolt? Mine is an arp with a pretty big head. Think it uses like 16mm or similiar size.
Click to expand...

Yes, it was. I was able to get a replacement bolt from Weber and transfer the bearing onto the new one.


K.
 
The Radius Kid said:
Then they're brain dead jackwagons.
Click to expand...

Looks Guys ,I only posted this thread to help out someone in the future.Im NOT going to throw any stones here.I have been into these cars since 87 and working on them since 95
I sure miss the good ol days
Seems like every thread turns into a bash someone or something with the stroke of a key.Thats why I only get on here to help someone or buy and sell something.
Looks like the aluminum spacer may be a probem if the crush or torque goes away.This is my first roller cam as I have always ran a bunch of junk left over stock stuff in the past.Ill keep everyone posted on results and thanks for everyones input
 
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