Posted By: CYACOP
440 Cam is tight - 10/17/09 11:09 PM
How forgiving is this problem?
I can roll it with a screwdriver pivoting off one of the timing chain cover bolts to the timing chain gear but I dont like the way it doesnt float in the new cam bearings. Its a new cam as well. Any feed back? I dont want to sand down the bearings either. Will it free up after startup?
Posted By: 1_WILD_RT
Re: 440 Cam is tight - 10/17/09 11:21 PM
New engine? Or just a cam swap? If it's a new engine the bearings need to be scraped for clearance, typically done by taking the old cam, cut slices across each bearing journal then use the cam to clearance the new bearings...
Posted By: Danan
Re: 440 Cam is tight - 10/17/09 11:26 PM
OK, I'll take a stab at this..
First off, is it tight with a little oil on it or is it tight with thick assembly lube? I've tried several methods of freeing up cams, and I'm not enthused about any of them. I heard one good way to do it is to grind slots in the journals of an old cam and then dress the edges so they are clean and flush with the bearing circumference. You then insert this 'tool' and slowly turn it until it cuts/scrapes the high spots down. This seems like a good idea but I always forget about making the 'tools' and always pitch my old cams. Otherwise, I've scraped bearings and even sanded them when I was trying to just knock an edge down. I suppose you could try to find an old bearing scraper, but I've never seen one for sale, so I don't know how likely that would be.
That said, providing you aren't running a lot of spring pressure or high rpm, you should probably be okay if one journal has a bit of a tight spot. The cam doesn't take a lot of abuse in a street engine, and I got 100k plus miles out of a truck engine with a pretty tight cam. I normally don't suggest allowing components to 'self-clearance', but it worked in this instance. I've found that small blocks are WAY worse than big blocks when it comes to misalignment in the cam bores. Just one of many reasons to build a big block! Keep us posted..
Posted By: Neil
Re: 440 Cam is tight - 10/17/09 11:30 PM
Check your cam bearings for any nicks or burrs. I paid the shop to install my last set and learned my lesson. Just one more part I will be doing myself from now on.
Posted By: 440challenger
Re: 440 Cam is tight - 10/17/09 11:40 PM
I used a brake drum hone, but supposedly that is the wrong way to do it. I like the old cam trick
Posted By: Stanton
Re: 440 Cam is tight - 10/18/09 12:34 AM
WARNING !!! This is a problem you definately want to rectify. I had this problem and thought it would go away once the motor was fired and running. NOT !!! The bearing ended up seizing to the cam enough to spin in its bore. I ended up cutting it and peeling it off before I could get the cam out of the motor. If its #4 you could be in deep trouble!
Posted By: 440newport
Re: 440 Cam is tight - 10/18/09 01:28 AM
When I rebuilt my 400 with new cam bearings I had the same problem. I tried the cutting slots in the old cam trick and it worked like a charm. The only advise I can give is, when you do it only turn the cam a little and remove it again to clean the bearing material out of the slots you cut and repeat. Nobody mentioned this before I did mine...After turning the cam around a few times the slots filled up and embedded pieces of bearing material in the cam bearings...I was able to clean them up again after pretty easily, but it could have been avoided.
Posted By: Dads426
Re: 440 Cam is tight - 10/18/09 04:05 AM
On our 340 the machine shop mushroomed the front of the rear cam bearing (from hitting it in). Scraped the edge of the bearing and the cam turned fine. There were noticable shiney spots on the front of the bearing when the cam was test fitted and wouldn't turn. Look carefully at the entire bearing.
Posted By: CYACOP
Re: 440 Cam is tight - 10/18/09 12:24 PM
Update:
Took my 4 1/2" grinder to the old cam and made the tool. Duct taped the lubes so I wouldnt cause more damage with nicks and reamed the bore. Took very little. Cleaned out the holes and checked new cam and moves like it should.
Thanks for the help, I appreciate your feedback.
Posted By: RapidRobert
Re: 440 Cam is tight - 10/18/09 04:17 PM
Glad you got it. I used to use a fine brake hone but after a prior thread on this touting the ease & advantages of slotting an old cam & how it worked for you on my next one that's what I am going to do.