Fitting Cam BearingsMay 19 2017 at 4:02 PM
|Dustin (Login HarleyJack)|
How is it done? Need to fit my #5 bearing. Cam is straight, and I have checked / tried to make sure bearing is square as can be. Smart move would be take it to the shop but I don't want to give in!
Without putting dye to it, looks like it is contacting almost all the way around inside the bearing just inside the bearing about . About 1/2 the distance to the oil hole in the bearing. I have an old cam, not a scrap one, but one I don't need that was given to me I could cut a grove in but not certain on how that is done either. Seeking some input/methods that work for you all. Thanks in advance.
|This message has been edited by HarleyJack on May 19, 2017 4:03 PM|
(Select Login johnvermeersch501)
Before you start to cut brgs, make sure the cam
|May 19 2017, 5:07 PM |
is straight and correct size. Two "V" blocks and a dial indicator will tell the story...
|May 19 2017, 7:10 PM |
Set old cam I am using up in Vblocks and did that. Pulled new cam out of box and same thing. Both are fine so that isn't it. Also fabbed a puller up at work to try pulling the bearing vs. driving it in. Used a second new bearing just to eliminate another variable. No help. Also checked by having only front and rear in...stops dead when you stick it. Guess the only thing I have yet to do is actually run a bore gauge into it just to see how far off it is! Just frustrating since its straight forward process. Don't see how the bore centerline could be off substantially since it was fine prior to tear down. This was a fresh rebuild to begin with. Guess what I am saying is that it all points to bearing needing to be "massaged" but I have never seen it done so curious on the "how". What gets me is that it's not tight. Smooth as butter until you hit last bore and its done. No turning no nothing. Goes in about half way on front journal and your done. Really this is why I question if having it on jack stand and main caps off could contribute. Sounds far fetched but when I did this 4 months ago engine was bolted differently to my mounting plate and I think mains were on and torqued. If it rains tomorrow I will know for a fact bc it's going on the bench.
You can do it a couple of ways....
|May 20 2017, 2:01 PM |
1. Pop that bearing out, look at the witness marks, take a bearing scraper and scrape away the tight spots. Drive it back in. If it's the first time going back in, it will be fine. But if you take it out to fix it again, put a drop of green Loctite on it.
2. Take your old cam, use a Dremel with a cut-off wheel, and cut a groove across the width of the rear cam journal. Don't dress it. Put the cam in, turn it over and let the cam clearance the bearing. You will need to re-wash the block again, and spray parts cleaner down the rear vertical oil passage to wash any particles out.
Are the cam bearings coated ?
|May 20 2017, 9:14 PM |
I've used the coated bearings a few times and there very hard to get the cam to fit. Never again will I use coated cam bearings. Brents way is very good.
|May 21 2017, 1:16 PM |
I did Brent's method and it os a lot better but still not what I am happy with. It should spin like butter and it won't. Think I will hit it with some blue and see what that shows one last time. You can still feel a tight spot and takes more force than I want to spin it. I am about one more try from giving it and making the hour drive to the shop. Better safe than sorry.
|May 22 2017, 10:39 AM |
The sacrificial cam is actually the easiest way. While you spin it, move it axially so that it catches all of the bearing.
|May 22 2017, 8:07 PM |
I took an old cam I had and cut it into a single tooth reamer like you and some posts i found said. I moved it though the cam bearing all the way but may need to do it once more. Still not buttery smooth when I slip a good cam in. Comparing it to journals 1-4 when I stick it in last journal it still hits a tight spot. Not major but I think it should be same as others and be silky smooth. I am gonna give it one more shot but then it's going to the shop if not right. Better to be safe than sorry. Beyond me why it has fought me this hard! I did run a bore gauge and compare the original to the new one and found the "used" #5 bearing to be more "open" by close to a thou. That is unloaded not installed. Didn't expect quite that much.
My biggest concern is taking too much off with the cam/reamer and not knowing if all the babbit is gone and its running on steel! Correct me if I am weong but not a whole lot of material there.
Both Brent n/m
|May 23 2017, 10:17 PM |
Sometimes we need to dress them
|May 21 2017, 4:12 PM |
You can look at the witness marks to see where the problem is. We have done a lot better since Willy made up a bearing press fixture and mandrels to install the bearings instead of the typical rubber expando and big hammer deal. A bearing scraper or even a straight edge razor blade pulled backwards across the I.D. will often clear up the issue.
I am pretty convinced that the original bearings were installed in a semi-finished size and then a broach was pulled through to size them in the block. We have seen one or two blocks where the outside diameter was significantly off center on a spot or two - no way that a replacement bearing work in that block without major effort.