Cam bearings

Discuss mechanical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Cam bearings

Post by les »

In an attempt to get things moving again, I am looking to press in new cam bearings, after making an appropriate tool. Trying the bearings on the camshaft prior to this there is some play, so I'm hoping that when I eventually pull them in the clearance will be correct without line boring. I hope this is going to be the case, as apart from finding a place to take the block, I wonder how experienced anyone is in this procedure nowadays. I seem to remember someone here hinting that after fitting these bearings he was satisfied that they closed up slightly, as would be expected, and consequently gave an acceptable running clearance.

philthehill
Minor Maniac
Posts: 10767
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: Cam bearings

Post by philthehill »

Les
There will always be some play/movement between the camshaft bearing and camshaft when unfitted.
Once the bearings are squeezed/fitted into the block there will be considerably less play/movement.
If the bearings play ball and you are able to fit the camshaft you should be able to turn the camshaft with the bearings lubricated without feeling any resistance. If any resistance is felt the bearings will need to be line bored.

Personally I would give the block to an established/experienced engineering firm and let them then do the whole job including the line boring if that is required. They should require the camshaft that is ultimately going to be used in the block as the test piece.

Oselli advertise that for a cost of £80 (plus the usual) they will renew and line bore the cam shaft bearings in an 'A' Series.

http://www.oselli.com/service/engineeri ... ne_reaming

Over the years they have fitted and line bored several sets of camshaft bearings for me.

Use the £80 as a comparator at an local to you engine reconditioning company.

Please keep us informed as how you get on.
Phil

les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Cam bearings

Post by les »

Thanks Phil, and yes I'm aware these bearings 'crush' hence trying them on the cam just to confirm they had the expected play beforehand. It would have to be somewhere like Osseli or the place in the link, for me to have confidence a competent job will be done. I'm going to stick with the plan to at least fit the bearings, I want to ensure all the surfaces are clean and ready. If I need the line bore then so be it.
Incidentally you might like to check out Thurston engineering in Ongar, I took a Porsche head to them a while ago for some work, they made an excellent job. http://www.thurstonengineering.co.uk/

philthehill
Minor Maniac
Posts: 10767
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: Cam bearings

Post by philthehill »

The Thurston Engineering Co web site is a very good read.
They certainly have a large and varied catalogue of abilities.
If they were closer I would give them a try.

The company history and especially Eric Thurston's time in WW2 reminds me of my fathers military service during WW2.
My father was called up to the RASC and then when REME formed up from units of the RAOC and RASC he was transferred to REME and worked in a forward workshop always constantly moving with the action.
He was always pressing me to join REME as a regular but I would not have it but years later worked in a REME workshop starting as a fitter and latterly becoming a Production and Technical Officer (PTO 3).

Phil

les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Cam bearings

Post by les »

Glad you found it interesting, its amazing how one thing leads to another, bringing back memories from the most unexpected source. Thurston engineering is a pain to reach using the M25 prior to some country lanes, when I went there I was able to take my bike. Doubt that will be an option carrying an engine block!

ampwhu
Minor Addict
Posts: 769
Joined: Sat Oct 31, 2009 8:51 pm
Location: Epsom, Surrey
MMOC Member: No

Re: Cam bearings

Post by ampwhu »

I have just finished building a 1098 and fitted new camshaft bearings. I made a tool from 2 old brake pistons and some M10 stud. I wound all 3 in easily and posted the pictures on Facebook.

Camshaft turns nicely by hand now with no movement. Found it quite easy to do.
les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Cam bearings

Post by les »

I think you may have been the person to whom I referred to in my opening post, I hope to achieve a similar result. I have the studding just looking for the other items.

ampwhu
Minor Addict
Posts: 769
Joined: Sat Oct 31, 2009 8:51 pm
Location: Epsom, Surrey
MMOC Member: No

Re: Cam bearings

Post by ampwhu »

Let me take a picture tomorrow and I'll put it up here
ampwhu
Minor Addict
Posts: 769
Joined: Sat Oct 31, 2009 8:51 pm
Location: Epsom, Surrey
MMOC Member: No

Re: Cam bearings

Post by ampwhu »

Camshaft bearing tool.JPG
Camshaft bearing tool.JPG (38.29 KiB) Viewed 2672 times

I used mg midget pistons ( I had some old ones of these). perfect fit to be honest. I do have a couple spare 2nd hand ones of these.

drilled a centre hole in both but tapped one to M12 thread. a long M12 thread bolt and off you go.

I marked out where the oil gallery holes go and lined them up and gently wound them in.
Attachments
Camshaft bearing.JPG
Camshaft bearing.JPG (39.72 KiB) Viewed 2672 times
les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Cam bearings

Post by les »

Thanks for the pictures, I'm doing similar, the threaded stick is the length of the engine but using the same principle, I have substituted metal components for hard plywood items, not as sophisticated as your setup but I hope for success. At the slightest sign of problems I'll resort to metal.
I've kept the old bearings in case I need to give a final shove if the new ones need to go in further than flush.

les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Cam bearings

Post by les »

Just a quick update, fitted the larger rear cam bearing today, took some pulling in. Tried the appropriate camshaft journal and there's clearance. Got too cold, so do the others later. No one can accuse me of rushing things!!

philthehill
Minor Maniac
Posts: 10767
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: Cam bearings

Post by philthehill »

Les
It must have been cold as the larger cam bearing is at the front of the block.
Phil

les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Cam bearings

Post by les »

No wonder it took some pulling in ! :D

ampwhu
Minor Addict
Posts: 769
Joined: Sat Oct 31, 2009 8:51 pm
Location: Epsom, Surrey
MMOC Member: No

Re: Cam bearings

Post by ampwhu »

I found getting it in the correct position 1st the hard part (still rather easy). I used plenty of oil.
les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Cam bearings

Post by les »

I'm sure oil is ok, that was my preference but I read somewhere suggesting a sealant is used to prevent the unlikely event of the bearing revolving. I thought that situation was a bit far fetched so as a happy medium I assembled dry. Rightly or wrongly!

philthehill
Minor Maniac
Posts: 10767
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: Cam bearings

Post by philthehill »

Les
The three camshaft bearings should be inserted dry after the block camshaft bearing housings have been thoroughly cleaned of all traces of oil.
There should be no need to use sealant or locking fluid to hold the bearing in the block - the compression of the bearing is sufficient to hold the bearing in the block if fitted correctly.
If the camshaft is tight in one or more of the three bearings the camshaft bearings must be line bored.
There is a high possibility that if one or more of the bearings is tight when the camshaft is fitted the bearing will pick up and rotate in the block.
Phil

les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Cam bearings

Post by les »

Thanks for confirmation Phil, I prepared the appropriate area with brake cleaner, I'll do the same with the other two; middle and -----REAR! :D

les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Cam bearings

Post by les »

I’m thinking the oil slot in the rear bearing would be better positioned at the bottom, as viewed when the block is upright. Anyone feel differently? Slot just about seen at 12 o’clock in the picture.
6F52377B-F2E7-4100-A8D0-51468AFD7BD7.jpeg
6F52377B-F2E7-4100-A8D0-51468AFD7BD7.jpeg (1.68 MiB) Viewed 2515 times

philthehill
Minor Maniac
Posts: 10767
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: Cam bearings

Post by philthehill »

Les
Re the rear camshaft bearing - I have just checked the position of the cam bearing lubrication slot in my spare 1275cc Midget block - the cam bearings were fitted and line bored by Oselli - the slot is at the bottom as you propose.

Phil

les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Cam bearings

Post by les »

Thanks again for your information, I was thinking in that position it might hold tiny bit of oil for the next initial startup. Anyway slot at the bottom!

Post Reply