Does anyone know of a specific bearing setting tool which can be used so to correctly install the pair of outer lower cam bearings? These bearings are a SKF 6203 which has an O.D. of 40 mm and an I.D. of 17 mm. In order to set them properly, they need to be tapped into their recesses in the front cover by applying equal pressure on both the inner and the outer races together. It seems to me that a simple custom solid bushing which had an O.D. of 39.5 mm and an I.D. of 17.5 mm would be just the ticket, as this size of a bushing could then be used so to tap the bearing into place by applying equal pressure to both races. Or, does some similar setting tool already exist on the market which could simply be bought? Is anyone here a home hobby guy who owns a small lathe and who could machine such a custom bushing? Thanks - DM
I used a stack of fender washers with the old ring nut, that will get you flush. After that it was just a matter of tapping both inner and outer races in until the outer seats. They're not that tight, you don't have to pound on them. Don't forget the spring washer - amhik.
Presume you used the ring nut to ‘wind down’ the bearing into place. Without stripping the shaft threads........ sounds like a plan.....
I used a thick washer that just covered the inner and outer races and then slid a piece of pipe extension over the shaft so I could drive it in with my hammer.
Yes, ideally it would be nice to use a regular nut but hard to find one that size and thread pitch. If you tap the bearing in rather than using a nut on the shaft you're going to push the shaft and drive gear in until it hits the block inside the timing cover. It will pull back out when you put the new ring nut on and tighten it but I'd rather not push it in like that.
Thanks to all for your comments on this. Update (and for future 'Search' archive use): A trip to my local hardware store has brought forth a thick 9/16" flat washer. These washers are supposed to have a 5/8" (15.9 mm) I.D. and a 1-1/2" (38.1 mm) O.D. Upon getting it home and carefully measuring it, it turns out that the particular washer which I found has an actual I.D. of 0.64" (16.3 mm) and an actual O.D. of 1.48" (37.6 mm), so both the I.D. and the O.D. are a slight bit loose in their tolerances. The washer's 37.6 mm O.D. is a bit under the bearing's 40 mm O.D., but thankfully the bearing's outer race is wide enough such that the washer's perimeter edge comes into contact with the bearing's outer face surface all around. So, it was a simple matter to then take a small rotary grinder and to open up the washer's 0.64" (16.3 mm) I.D. to about o.70" (17.8 mm). Seems to me that this modified washer ought to now easily be used so to gently tap the bearing into place via supporting both of the bearing's inner and outer races equally. But, with all of this having been said, and since Paul so kindly brought it up, I'd like to ask a follow-up question: What purpose does that inner spring washer serve? The 308's shop manual does not specifically address anything critical or unusual about the installation of this spring washer. The manual simply indicates that the innermost snap ring is to first be installed, followed by the spring washer, then the bearing, and finally the outer snap ring. Nothing about how forcefully one should drive this bearing into the recess, but it seems logical that it should be done with a light touch so as not to compress the spring washer flat. My memory of the last time that I installed the current bearings is that it's a pretty snug fit for the bearing into the engine front cover's recess (and thus, my original question). So if the purpose of the spring washer is to try to push the bearing out and away from the center of the engine, then one might think that the bearing should be designed to fit a bit looser into the front cover's recess, allowing the bearing to 'wiggle around' in the recess, with the spring washer serving the purpose of placing a bit of outward force onto the bearing's outer race. Or, am I missing something here?
You're over-thinking it. The spring washer just takes up the slack as it would be difficult to have the distance between the two snap rings meet the exact tolerances of the bearing width. So there can be no movement of the outer race in the timing cover bore which could over time create wear. The reason I mentioned it is because I did in fact forget to install it on the first bearing I did. After talking with some old-time gurus it was determined that rather than destroy a new bearing pulling it out again it would be perfectly acceptable to put the spring washer under the outer snap ring. It does the same thing.
Aha! Merely a slack space tolerance taker-upper! Now it all makes much more sense! Thanks for the insight! - DM
You guys got me thinking...I have done this job just about 11 months ago and can't remember if I put them back or not . I would assume there is no way of telling weather they have been installed or not? I would really hate to take everything apart at this time..
Well!!! A BIG THANK YOU for starting this post... I just pulled the brand new bearings and nothing there I have to say that I have bought the vehicle with catastrophic failure of the bearings and upon disassembly they were not there and I paid no attention to the parts diagram.(my bad). Possible saved me from a second failure. In any case I would assume that I have to replace the bearing nuts again even though the engine was not cranked? (still out of the vehicle)
I wouldn’t hesitate to use them again. If the locking lip is damaged a lot where you previously tapped it into the groove, you can lap the bottom of the nut a little with some fine water paper on a flat surface (rotating it frequently) which will give you a new part of the lip to tap in. Try to get the NTN bearings if you damaged yours taking them out (NTN 6203LLUA1C4.) Whatever you use, make sure they are C4 clearance and from a good source as there are so many counterfeit SKF bearings out there.
Derek, I inspected the gear nuts and appeared to be just fine. I had them replaced with the updated version that SP has. Also the bearings were from the same source and they were SKF C4 bearings. What was a surprise to me is that going through the service history of the previous owner, the bearings were replaced at a Ferrari dealer repair facility and they did not install the spring washers. Oh well that's the past.. Thanks for the guidance.
Had an engine builder and great machinist, who I know make me one out of alloy. $20.00. Took him 10 mins. 1 inch wide. Used it to get the bearing to seat in the recess. Went in like a hot knife through butter. I also used a stack of washers to get it to the point where is was getting into the recess. Image Unavailable, Please Login
Got the bearings from mcmaster carr. And they gave me the higher speed SKF Explorer bearing: 6203 2RSL
Oops: 6203 2RS JEM it's C3 which I believe is the only choice available now. I spoke at lenghth with a product person at SKF. I know there is a lengthy thread on C3 vs C4 and it was a wash.
There is overlap in the clearance ranges from what I recall— about 25% of C3 will be in the C4 range (but 25% will be in the C2 range.) Speed is not an issue here but temp and load. The high temp SKF bearings originally fitted are no longer available and SF could not tell me the specs of their stock.
