Front cam bearing fitting - 1275 S engine

[Andrew1967]

Can anyone advise if this is correct ?

In order the for the lower oil hole in the block to not be partially covered by the cam bearing, the bearing has had to be fitted slightly inset in the block. The No 8 cam follower just passes the bearing.

If the bearing is placed centrally in the block wall, the oil ways are partially covered.

Looking at the replacement 148 cam journal, with it set at a position to allow for the front plate, it looks as though part of it has not run on a bearing, which would equate to the bearing being in the position as shown in the pictures.

One suggestion is to remove the bearing, elongate the hole/slot and re-fit ?

[Spider]

The Bearing is inset in the block, I don't know the exact measurement off hand as I have a gauge. It's around 2 - 3 mm and from your Photo, yours looks close or maybe a little too deep, but not much.

It sure does look to come inside the block a bit far though, but, as long as the Follower and the Cam Lobe clears (allowing for Cam End Float and some wear, though, if the Cam's ground correctly, it should always thrust in to the Thrust Plate / Sprocket), then that'll be fine.

[Andrew1967]

The cam follower does clear Spider, the machinist set the bearing so there was clearance but also allowing the oil way in the block to be totally clear.

I’ll have to dry assemble the front plate, cam and thrust to check lobe clearance.

[Polarsilver]

Andrew, i seem to remember a past Forum Post saying the Rocker Cover had an issue it was filling up with Oil & could not drain out quick enough & the solution was an incorrect fitted Cam Bearing ?

[Andrew1967]

I saw a post about that as well Norman, but was unsure if it related to the same issue I have.

[Aussie Bill B]

Was this the topic you are referring to?

viewtopic.php?f=3&t=25689&hilit=Oil+roc ... r&start=60

[Exminiman]

Was this the topic you are referring to?

viewtopic.php?f=3&t=25689&hilit=Oil+roc ... r&start=60

Page three of that thread might help, just in case bearing is fitted in wrong position......

5A110611-2962-4B16-8C13-5B9AD22F0810.jpeg

[Andrew1967]

Thanks for the posts everyone

I've spoken to Simon N and apparently it's a common problem with the crap Chinese cam bearings now available. Basically the holes are in the wrong place

ACL and AE bearings are getting hard to find, which are correct.

It is possible to gently file/die grind the hole out in the bearing to allow better fitment but partial coverage of the oil-way does not seem to have any adverse effect.

[Exminiman]

Is it only ACL and AE bearings that are correct , any idea who makes Mini Spares ones ?

Its just i have to replace some......

[Andrew1967]

Best to ask Simon or maybe he will post up here

Mine did it come from MiniSpares, can’t remember where now, possibly off an autojumble stall at Stanford last year. Having said that, where they come from originally ...

[Andrew1967]

Front and centre bearings are same as 998, it’s just the rear that differs on the big bore blocks.

Just checked my Glacier reference manual.

[iain1967s]

Open tappet chest blocks use a narrow rear bearing [set VPC956 / 28G133]
Solid wall blocks upgraded to a wider rear bearing [set VPC989 / 8G2392]

As the 1275 S blocks are open tappet chest, I wasn’t sure if they should be the narrow type? But then again, the do have the deeper oil pump nose which suggests the wider type...

I can’t be 100% sure because page MA52.1 is missing from the AKD3509 scan on the main website... so I ordered both sizes for my engine rebuild. “Better to be looking at it, than for it”

[Exminiman]

Swifttune sell AE, MED sell ACL, SH Engineering ACL, bit of a pattern going on.......

Minispares don't quote manufacturer

[Andrew1967]

Here's a copy of the Glacier reference page ...

[Spider]

ACL are still making them and widely available here. As there are not only first class bearings, they are also OEM in our locally assembled engines - I wouldn't use anything else.

[Andrew1967]

My machinist has a new set of AE Glacier 998 bearings so we are going to use the front and middle bearings from that set. The rear bearing was replaced with the other two and seems OK so we will leave that.

Another thing to look out for at auto jumbles !!

[iain1967s]

BMC OEM were Vandervell, just got these NOS off eBay

[Vegard]

Andrew, i seem to remember a past Forum Post saying the Rocker Cover had an issue it was filling up with Oil & could not drain out quick enough & the solution was an incorrect fitted Cam Bearing ?

I don't think I believe that. A mini top end will drain LOADS of oil. There just cannot be sufficient flow through the rocker pedestal to overcome the drainage.