camshaft wont fit

[74roadrunner440]

hey guys here a odd one. i got my 440 back from machine shop on thursday. they put the short block to geather for me and installed cam bearings. but my cam shaft wont fit into the last journal. its so tight it wont turn bearings ar instaled right n strait. never had this prob before and help would be greatly appreciated thanks again all.

 

[BigBlock61]

I had the same problem once. The machine shop told me the block was twisted and that's why the cam wouldn't go in with the new bearings. They had to shave my cam bearings to get the cam to go in.

 

[Gpuller]

Think its pretty common. Brother has a 440 that was rebuilt and it wiped out a cam lobe. When we pulled the cam one of the bearings came with the cam. He remembered the machinist saying he had to shave a cam bearing. Didn't shave enough I guess.

 

[moparsteve636]

I believe it's called core shift , You can either shave the bearings or polish the cam one -two thou.

 

[74roadrunner440]

wow thats odd because the old cam fit perfectly

 

[dryheat]

Back in the 70's I did a 383 stock rebuild and could not get the Sealed Power cam to slide in. The cam bearings I used was from a different manufacturer. I went and got the sealed power bearings and the cam fit perfectly.

 

[74roadrunner440]

didnt think u could chave the bearing with out ruing the riding surface
how do u shave the bearings

- - - Updated - - -

now what can i do take back to machine shop and have them shaved or get difrent ones i bough some dura bond bearings will these work?

 

[GrabberOrange69]

This can be a problem in other engine makes also. Figure out where the interference is and gently scothchbrite the area on the end cam bearing. Done it a few times on small and big block fords with no trouble. That your original cam slides in with adequate clearance is a good sign were only talking about a few thousands of an inch. It will be a pain in the arse, but take your time and be very careful of shavings if the reciprocating mass is installed.

Good luck!

 

[MoparMitch]

Here is a way that Rusty Rat Rod taught me. If you have an old camshaft , cut one relief groove in each cam journal about 30 Deg off of perpendicular. Cut them with a wizz wheel about .040 deep. Use an old cam gear on it, and pack the journals with grease. Insert your new cam tool while turning clockwise. Make a few turns after it is all the way in. Remove and clean the shavings from said camshaft tool. This will leave very few, if any in the motor. I did this on mine , and then reached through the lifter galley where I could to see if any shavings were there. Mine runs fine. Saves alot of work to redo the bearings. Hope that helps.

 

[99ss]

Why cant you turn the cam where it needs to be smaller?

 

[Hemirunner]

The bearings are the sacrificial lamb in the situation. You don't want to alter the cam to fit. Typically, the bearings are just cocked in the bore to the point that the cam wont' slide in. A lot of times, you can just straighten up the bearings with a cam tool. Other times, you have to get out the cutter cam and make things fit. Cams are precision ground. If the average Joe tries to take off a thou, He'll usually end up rounding the journal and causing a cam that won't ride on an oil wedge but happily digs into the bearing. Most guys skilled with a crank polisher and using the right size belt might get you a half thou, but it isn't easy to do.

 

[Jasoncoronet]

Here is a way that Rusty Rat Rod taught me. If you have an old camshaft , cut one relief groove in each cam journal about 30 Deg off of perpendicular. Cut them with a wizz wheel about .040 deep. Use an old cam gear on it, and pack the journals with grease. Insert your new cam tool while turning clockwise. Make a few turns after it is all the way in. Remove and clean the shavings from said camshaft tool. This will leave very few, if any in the motor. I did this on mine , and then reached through the lifter galley where I could to see if any shavings were there. Mine runs fine. Saves alot of work to redo the bearings. Hope that helps.

This the correct way to fix it. I watched my engine builder do the same thing. Make sure to use the grease like he said. Dont worry this is very common and no big deal.

 

[Cranky]

Block is twisted, core shift...man. As for core shift, the block is machined after the block is cast so it doesn't matter if the core shifted during the pour. Twisted block...you have to get one really really hot to make it twist enough to make a cam not want to go in and if that was the case, the crank probably wouldn't turn either. First off, check the cam to make sure it's on size and not bent. I've seen more bent cams (excessive run out) than blocks that were not straight. Yup, brand new cams can have run out and not be on size. Also, universal cam tools can let the bearing shell crush too much when it's installed. Also, the cam bores can be on the tight side but I've never found any that were under sized. After dealing with this issue a few times, I built my own cam bearing tool and so far so good. If all of that is good and you still have problems, then shave the bearings.....

 

[74roadrunner440]

all the bearing ar flush n striat in the bores im thinking i need to grind them down but im confused on what u guys are talking about and how to take som meaterial off the bearings

 

[747mopar]

Here is a way that Rusty Rat Rod taught me. If you have an old camshaft , cut one relief groove in each cam journal about 30 Deg off of perpendicular. Cut them with a wizz wheel about .040 deep. Use an old cam gear on it, and pack the journals with grease. Insert your new cam tool while turning clockwise. Make a few turns after it is all the way in. Remove and clean the shavings from said camshaft tool. This will leave very few, if any in the motor. I did this on mine , and then reached through the lifter galley where I could to see if any shavings were there. Mine runs fine. Saves alot of work to redo the bearings. Hope that helps.

Sweet trick, My machine shop wanted the cam so they could ensure a good fit but it's nice to know this trick for future builds.

 

[Supershafts]

Lol at the reasons given for this ALL TOO COMMON ISSUE... If i put together 20 bb's this week, 19 will need a cam bearing modified.

The bearing is not cocked, the bearing is just being squeezed more from the inconsistent machining of the cam bores, JUST LIKE the lifter bores all not on the same angle.

You need to hone the bearing that has the problem, or you can cut the cam journal after you bore gauge that bearing and have a crank grinder... SO you'll have to very carefully hone the bearing like i do.

.

 

[74roadrunner440]

if any one has a pic of this new found tool would be greatly appreciated

 

[Meep-Meep]

Set the cam on Vee blocks and see if it's bent. I had it happen twice! A good one will be in the 0 - .0015" range. I had one that was .010"!

 

[bm02tj]

they make a proper bearing knife to shave the bearing on the high spots

 

[99ss]

The bearings are the sacrificial lamb in the situation. You don't want to alter the cam to fit. Typically, the bearings are just cocked in the bore to the point that the cam wont' slide in. A lot of times, you can just straighten up the bearings with a cam tool. Other times, you have to get out the cutter cam and make things fit. Cams are precision ground. If the average Joe tries to take off a thou, He'll usually end up rounding the journal and causing a cam that won't ride on an oil wedge but happily digs into the bearing. Most guys skilled with a crank polisher and using the right size belt might get you a half thou, but it isn't easy to do.

Thats what my builder does.