16 replies to this topic

[Tony P]

Dont wont to sound a dick , but need advice on camshaft bearings.

 

I am going to fit a new camshaft, and did buy new bearings.However the old ones look very good,  its pretty easy to take the old ones out, but hard to put back the new ones in.  Without a machine shops help, or a £200 tool?

 

The new shaft is very tight in the old  bearings and cant be turned by hand, this was the case with the old shaft?

 

Do you think i can put some Valve grinding paste, onto the old camshaft  to hone the bearings to fit the new camshaft?

 

Thanks

 

Tony 

Edited by Tony P, 03 October 2014 - 01:14 PM.

[robminibcy]

definitly dont put valve grinding paste on the camshaft!! it will destroy your engine, as for bearings i thought that they need reamed to size which would require machining but i may be wrong.

[Tony P]

Was just thinking of using fine paste on the old shaft to open the bearings up a little, so the new shaft would turn by hand?? Has anyone done this before and did it work , or can it work.

Regards

Tony

[jaydee]

There are several different bearings for differnt A series engines. And yes in some cases its necessary to get them reamed.

Did you already took off your old bearings? Because if not catastrofically worn Measure clearance), its not really necessary to replace them, its just sales pitch.

[Cooperman]

DO NOT USE GRINDING PASTE INSIDE THE ENGINE ANYWHERE!

If the cam bearings are basically in good condition don't change them. The camshaft should rotate easily by hand, but it should feel firm to turn. Lightly oil the bearings when doing the trial build of the cam. If it won't turn by hand it needs light machining at a machine shop. If that is the case you might as well get new bearings pressed in as the cost won't be much different. Just supply the new bearings and the new cam to the m/c shop and they'll do the rest.

[ACDodd]

Where are you I charge £30 to fit customer supplied bearings, and no they do not need to be reamed. Bearings are now sold as pre finished. All that is needed is a good old fashioned bearing scraper if they come up a little tight.

As Cooperman said DO NOT put grind paste in there!


Ac

Edited by ACDodd, 03 October 2014 - 06:35 PM.

[Tony P]

Sorry to cause a storm, 

 

Where are you I charge £30 to fit customer supplied bearings, and no they do not need to be reamed. Bearings are now sold as pre finished. All that is needed is a good old fashioned bearing scraper if they come up a little tight.

As Cooperman said DO NOT put grind paste in there!


Ac

Hi ACDodd,

Sorry to cause such a storm, with the grind paste. I am in Essex . Are you any where near?

Regards

Tony  

[ACDodd]

I am in Salisbury, wiltshire.

AC

[Earwax]

Tony P, you didn't cause a storm, you asked a very valid question, and just as all good forums are supposed to do, some clever minds pointed you in the correct direction.... keep asking..

[Tony P]

One last question, when people say you should be able to " turn the cam by hand " does this mean without anything attached to the end, just the getting your hand on the 2 inches sticking out, without  the  timing cog attached???

 

Tony P

[The Matt]

Timing gear on. It'll be very difficult to turn it without.

[ACDodd]

With no followers and just the cam fitted it should rotate easily with just 2 fingers. No sprocket fitted or nut.

Ac

[mini13]

yep as above, really shouldnt be too hard to turn,

 

 

if theyre tight its normally due to careless fitment, they must be "pulled in" using mandrells if they are knocked it they will distort.

 

also kncoking the cam against them during fitment can cause dents, and raised patches, in chich case gest hold of a bearing scraper and scrape off the high bits,

 

I have had success making bearing scrapers from old three sided files... grind the file face off using a bench grinder so the three faces are slightly concave, then sharpen it on an oil stone, easier to buy one though....

 

also, do check the camshaft bearing journels for marks, this can also make them hang up.

[HarrysMini]

Where are you I charge £30 to fit customer supplied bearings, and no they do not need to be reamed. Bearings are now sold as pre finished. All that is needed is a good old fashioned bearing scraper if they come up a little tight.

As Cooperman said DO NOT put grind paste in there!


Ac

Is bearing scraping a service you could provide? I'm having issues with my cam bearings (the cam won't turn unless the sprocket is on) and there are shiny spots which I guess would indicate a raised area. 

 

I've been told they need to be reamed, however you are saying they don't?

[ACDodd]

Certainly, I scrape bearings to ensure proper clearances.

Ac

Edited by ACDodd, 04 October 2014 - 10:05 PM.