TR4/4A I Replaced the Cam Bearings

KVH

Darth Vader

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• May 9, 2019

• #1

I had this done at a great shop but they look strange. I see three bearing holes in at least two of the bearings--the one for the locating bolt, one dry one I can't explain, and a smaller one to the oil galley. It looks like the shop may have needed to drill the one to the galley, but I can't tell. I'll call and ask them. It's a bit smaller than the other two.

Should they all line up, or is some machining typically needed? It's too awkward for pictures since a couple of the holes (maybe all) are on the upper part of the bearing.

Thanks.

 

OP

KVH

Darth Vader

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• May 9, 2019

• #2

Well, I took another look. They definitely got the bearings off somehow and then drilled one hole bigger and another relocated for the galley. They may tell me they had no choice. It appears close, but one of the locating bolts appears to have given them a problem, so they made that hole a bit larger, then relocated the oil galley hole. I'm guessing, since they do know their work, that they'll tell me the extra hole and widened hole will not impact life or performance and that if the cam can ride on two holes in any given bearing, it can ride just as well on three. Any thoughts there? Will I be 110 years old before this is an issue?

 

TR3driver

Great Pumpkin - R.I.P

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• May 9, 2019

• #3

There should be NO machining required. If the inserts are properly installed, all the holes will line up (except the one blind hole, of course).

But it isn't obvious that the rear bearing has a front and back. The ones I've gotten are not marked, but if you install them backwards, one of the holes won't line up. Took me 3 or 4 tries the first time to get it right. IIRC the center bearing (which does have an unused hole, the insert is the same as the rear bearing) can go either way.

Stuffing in apparently wrong bearings and then poking holes in them strikes me as sloppy work. Might be OK tho, if the cam spins absolutely free (without lifters of course) and all the swarf got cleaned out. The clearance to the cam journals is pretty tight, though, and it's easy to distort the inserts, especially if you install the locating pegs with the insert not lined up "just so".

 

OP

KVH

Darth Vader

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• May 9, 2019

• #4

OK, thanks. I'll see what the shop says.

 

OP

KVH

Darth Vader

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• May 9, 2019

• #5

OK, here is the answer. Cam bearing was off a bit and was too difficult to adjust and they felt it would be unnecessary to press it out and reset it because they were able to remove the oil galley plug and carefully drill into the underside of the bearing for access to the oil galley. Everything was done properly I’m told, with machining and chamfers, All shavings were cleaned and removed entirely from the block. The machinist says he’s positive everything will be fine.

I’m trying to imagine how you can access the oil galley by using a drill in the oil plug hole, but they say there were no new holes put in the galley or block, and that the only access was through the plug hole.

Does this make you nervous?

 

M

malbaby

Jedi Warrior

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• May 9, 2019

• #6

May I ask the reason for replacing the cam bearings, as that has ramifications on correct camshaft installation.

 

TR3driver

Great Pumpkin - R.I.P

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• May 9, 2019

• #7

It's been awhile since I looked, but I think that is right. The plug in the side of the block is where the factory drilled a hole from the oil gallery through to the rear cam bearing, as well as another hole down to feed the rear main bearing.
The other important hole in the rear cam bearing could be accessed with the head removed, by drilling down through the oil hole in the back of the block.

That's the one that's hard to see; and it seems they didn't mention it ...

 

charleyf

Luke Skywalker

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• May 9, 2019

• #8

That last hole Randall is referring to is extremely important as it provides oil up from the rear cam bearing through the block then into the head and oils the rocker shaft. If that hole is not properly aligned , you get no oil to the rocker shaft.

 

OP

KVH

Darth Vader

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• May 9, 2019

• #9

Yes that rear hole is open and fine, all the way to the rocker. I think I can keep trudging forward. I’ll spin the cam first per Randall’s Suggestion.

 

D

DavidApp

Yoda

Gold

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• May 10, 2019

• #10

The story you get from the shop is not always completely accurate.

The shop that pickle my TR3A motor returned it with what looks like a plumbing plug in the water jacket opening in the head. There is normally an aluminum plug there.
When I asked the shop they denied all knowledge of the plug. In their defense I did not check it before I dropped it off so it could have been the PO.
I could not get it to move so as it is not leaking and the valve cover fits I have left it.

David

 

Sarastro

Obi Wan

Silver

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• May 10, 2019

• #11

Those bearings can be installed at least 12,389.7 different ways, maybe more, and only one is right. Then, it's a real pain to get them aligned so that all the oil passageways are clear. Like (probably) everyone else, I had to install some of the bearings a couple times before they were right.

Anyway, here's my story, with possibly some useful info:

http://www.nonlintec.com/tr4a/engine/#block_reassembly

Scroll down a bit to the camshaft section. I hope it's all correct; it's so confusing that even now, after doing it a couple times, I wonder.

 

M

malbaby

Jedi Warrior

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• May 10, 2019

• #12

A "great shop" should not resort to drilling a bearing....maybe not so great.
I was fortunate that a specialist machine shop was not far away from where I live.
They do work on exotic engines, including manufacturing bearings etc.
They remetalled my old bearings, inserted them into the bare block as per original fitment, then line bored the cam bearings in situ to exactly fit my camshaft. It's a similar way as you would have your engine block tunnel line bored [if necessay] for perfect crankshaft/bearing fit.

 

OP

KVH

Darth Vader

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• Nov 18, 2022

• #13

malbaby said:

May I ask the reason for replacing the cam bearings, as that has ramifications on correct camshaft installation.

Click to expand...

Here I am three years later, finally rebuilding, and I’m stuck. The bearings are too tight. Your question may have been an important one. Anyway, I’m off to the shop to see what can be done.

 

OP

KVH

Darth Vader

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• Nov 18, 2022

• #14

Sarastro said:

Those bearings can be installed at least 12,389.7 different ways, maybe more, and only one is right. Then, it's a real pain to get them aligned so that all the oil passageways are clear. Like (probably) everyone else, I had to install some of the bearings a couple times before they were right.

Anyway, here's my story, with possibly some useful info:

> Engine Rebuild <

Scroll down a bit to the camshaft section. I hope it's all correct; it's so confusing that even now, after doing it a couple times, I wonder.

Click to expand...

Are you able to send a pic of that homemade cam bearing puller?

I’m reading your old post and learning from what you did back then.

Thx

 

OP

KVH

Darth Vader

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• Nov 18, 2022

• #15

I’m just now leaving my machine shop. They have at least 70 engines on the floor in various states of rebuilding and repair, another 50 or so odd components including cylinder heads, intake manifolds, and exhaust manifolds, and at least 75 crankshaft ready for customer pick up or rework, and probably 15 or so cam shaft projects underway. What a magnificent wonder it is to still have shops like this operating and in existence just like they were in the 60s. I know it’s too good to be true, but I sure hope the guy never retires , because there will be no one to replace him.

He told me that tight bearings can be normal, to put the engine back together, to start it up, and enjoy the ride. For a number of reasons, I know the advice is right on the mark.

 

CJD

Yoda

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• Nov 18, 2022

• #16

Often the bearings get a little ridge at the end that gets hammered. If you run you finger over the edges it will be obvious. A sharp hobby knife can be used to trim the ridge, if there is one. Past that, so long as you can get the cam in, it is not too tight.

 

Sarastro

Obi Wan

Silver

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• Nov 18, 2022

• #17

KVH said:

Are you able to send a pic of that homemade cam bearing puller?

I’m reading your old post and learning from what you did back then.

Thx

Click to expand...

There is a picture in the post. Go to

> Engine Rebuild <

and scroll up a bit to the last pics in the previous section.

 

M

malbaby

Jedi Warrior

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• Nov 18, 2022

• #18

"He told me that tight bearings can be normal, to put the engine back together, to start it up, and enjoy the ride".
That is rubbish......True that new cam bearings can be "tight" when fitted, but they should then be line bored to suit the cam for optimum fit.

 

CJD

Yoda

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• Nov 18, 2022

• #19

The cam gallery is line bored at the factory. I have never had a problem with a block warping in the area of the cam gallery, and I have never had to line bore cam bearings after installation. That is not a common procedure.

The TR2 block does not have separate cam bearings, with the cam riding on the cast iron block material. If the TR2 cam bearings wear, then you must have the cam gallery line bored to accept separate bearing inserts. Still, you should not have to line bore the inserts after installation.

 

OP

KVH

Darth Vader

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• Nov 19, 2022

• #20

The guys. Appreciate the advice.