On The Road
Posted 01 December 2014 - 07:33 PM
I have my 1275 in bits and ready to rebuild. I'm fitting new cam bearings and found these are really tight in the housing. Anyone fitted these before? Any tips.
It's looking like I'll have to press them using a piece of threaded bar and some nuts and washers. I have also put the bearings in the freezer over night to try and shrink them slightly.
Dave
Up Into Fourth
Posted 01 December 2014 - 07:46 PM
you definatly need to "pull" them in with threaded bar,
really you need somthing that will pull them below the surface of the block to get them properly alighned,
below is the tool I made for fitting cam bearings, it can be used to pull old ones out as it'l pass through the block.
also, make sure the tining chain end one is in the right way round, there should be a notch, which goes to the outside, it needs to be inthe correct way to regulate the oil flow to the rockers.
On The Road
Posted 01 December 2014 - 08:41 PM
You wouldn't like to send that to me would you? postage paid both ways of course. Great idea. If I go on the lathe at work and make one it will take ages and I also have work to do as well.
Dave
Super Mini Mad
Posted 02 December 2014 - 07:49 AM
Super Mini Mad
Posted 02 December 2014 - 09:27 AM
How about sending the dimensions to Mini Spares so they can knock up a few and make them generally available.
Moved Into The Garage
Posted 02 December 2014 - 01:03 PM
This is not the suggestion you want, however....
Take the block, cam bearings, and cam to the machine shop that is working on your engine and have them install the bearings. It is very likely that the bearings will require sizing after installation so the cam can be installed and turn freely. That's why you take the cam to the machine shop. While I am sure you can install the bearings, if you find they are "tight" on the cam, sizing the bearings is something I personally don't want to do at home with improvised tooling. Obviously this is your engine and your choice.
Super Mini Mad
Posted 02 December 2014 - 03:23 PM
This is not the suggestion you want, however....
Take the block, cam bearings, and cam to the machine shop that is working on your engine and have them install the bearings. It is very likely that the bearings will require sizing after installation so the cam can be installed and turn freely. That's why you take the cam to the machine shop. While I am sure you can install the bearings, if you find they are "tight" on the cam, sizing the bearings is something I personally don't want to do at home with improvised tooling. Obviously this is your engine and your choice.
Up Into Fourth
Posted 02 December 2014 - 03:35 PM
Pretty sure that dklawson and Craig89 are right and the new bearings need to be reamed to fit a new cam.
Formally known as chrome
Posted 02 December 2014 - 04:16 PM
I've fitted several different makes of bearings and yet to buy one that is designed to be reamed.
Unless you've even attempted to fit them yourselves, Please don't spread old wives tales! You definitely need to pull them in (not tap/drift them), so that is a good reason to take them to a shop if you don't want to make the tooling. Mini13's tool is the perfect solution, but you can get away with thick aluminium washers that are a fraction bigger than each bearing, if you don't have access to a lathe. Freezing the bearings won't help.
Maybe the stories about reaming were true half a century ago, but manufacturers can easily make them to size these days. It's ludicrous to think that a bearing manufacturer can make a 2 piece main or big end bearing (also a compression fit), yet can't make a cam bearing to size! Even if it were true, I think you'd struggle to find a machine shop that had the tooling to scrape a bearing to size these days.
On The Road
Posted 02 December 2014 - 04:38 PM
I've fitted several different makes of bearings and yet to buy one that is designed to be reamed.
Unless you've even attempted to fit them yourselves, Please don't spread old wives tales! You definitely need to pull them in (not tap/drift them), so that is a good reason to take them to a shop if you don't want to make the tooling. Mini13's tool is the perfect solution, but you can get away with thick aluminium washers that are a fraction bigger than each bearing, if you don't have access to a lathe. Freezing the bearings won't help.
Maybe the stories about reaming were true half a century ago, but manufacturers can easily make them to size these days. It's ludicrous to think that a bearing manufacturer can make a 2 piece main or big end bearing (also a compression fit), yet can't make a cam bearing to size! Even if it were true, I think you'd struggle to find a machine shop that had the tooling to scrape a bearing to size these days.
Totally agree with that post, you never ream a white metal bearing but you would blue them and scrape them in but again never on a car engine. I've got 35 years heavy engineering experience behind me and work on RR jet engines and gas turbines, all the experience I have tells me to ask the question first if anyone else has fitted these before.
I have a fully laden machine shop at work so if it comes to it I'll make the tooling required it will just take me longer to complete.
Formally known as chrome
Posted 02 December 2014 - 05:05 PM
You should have no trouble; My puller was relatively crude compared to the pictured one above, but worked all the same. If you go to the trouble of turned one up, consider making a few, I'm sure you could sell them on very easily.
Just to reiterate mini13's point below; I got stuck on this as I didn't take a photo first. Intuition says it's the wrong way around, but I've been advised it sits the way it does to limit the amount of oil going to the rockers otherwise it might flood the rocker cover!
also, make sure the tining chain end one is in the right way round, there should be a notch, which goes to the outside, it needs to be inthe correct way to regulate the oil flow to the rockers.
Edited by Phil-R, 02 December 2014 - 05:05 PM.
Moved Into The Garage
Posted 02 December 2014 - 05:29 PM
I don't dispute your experiences or your statements that sizing bearings should not be required. (Note however that I did not use the word "ream"). There have been a couple of threads here over the past few years where members did find their cam would not fit easily in freshly installed bearings. I believe it was AC Dodd who said in those instances light scraping of the bearings was sometimes required but it was not a common occurrence.
Regardless I will state as I did before that this is a task easily handled by the machine shop that is typically undertaking other block related tasks. While I do almost everything myself, tasks like these I leave for others. Again, it is your engine and your choice.
Up Into Fourth
Posted 02 December 2014 - 07:06 PM
Scraping is sometimes needed to ease the fit. I use a good old fashioned bearing scraper to do mine (home made) an yes it did learn it properly, I completed a stint at the bluebell railway many years ago (during my engineering apprenticship) where I was my job to bore and scrape white metal axle boxes to fit 6 inch journals!!
AC
Moved Into The Garage
Posted 02 December 2014 - 08:16 PM
I also have to say all Cam Bearings I've bought over the past 30+ years have been finished to size, though as others have said, sometimes they do need scraping to put them 100% right, not for re-sizing but to correct for alignment. Although I do fit (and correct ours) if it's only one or two sets you'll be fitting, I'd suggest having the machine shop do all the worrying for you, most don't charge much to fit them.
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