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Bronze insert in camshaft

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bop
Posts: 95
Joined: Mon Feb 15, 2016 3:26 am
Location: Alberta Canada

Bronze insert in camshaft

Post by bop » Fri Feb 08, 2019 8:59 pm

I (have posted this topic on the Daimler forum) was wondering if anyone can answer this question. What is the purpose of bronze insert on rear bearing surface of camshaft, and what is it called?
2.JPG
1.JPG
It was not loose and appeared permanently installed, but may have been frozen in place from sitting for 40+ years. The bearing is pressure fed from the oil pump through the main bearing then on to the cam bearing. It is the rear cam bearing and the only thing different about this bearing area is that it has an outlet to which an external pipe to the engine is attached. This pipe delivers oil under pressure to the head to lubricate the top end.

This camshaft is from a 1935 Daimler 15, but seeing many parts are similar to both Lanchester and Daimler I thought someone on this forum might know the answer :D

thanks Bob

grahamemmett
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Location: Northwich, Cheshire
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Re: Bronze insert in camshaft

Post by grahamemmett » Fri Feb 08, 2019 11:19 pm

From my metallurgical days I recall that bronze is self lubricating and so I’d hazard a guess that it’s there to prevent seizure in case the oil supply is insufficient. Steel on steel seizes when the heat generated causes both surfaces to melt and fuse together. The bronze insert would prevent this.
It’s 44 years since I studied metallurgy so I could very very wrong but it’s plausible.
Graham Emmett
Northwich, Cheshire
Joint DB18 Registrar (with Marcel Renshaw)
DB18 1949 LCV522 (Yes that one with the P100s)
https://www.db18.org

bop
Posts: 95
Joined: Mon Feb 15, 2016 3:26 am
Location: Alberta Canada

Re: Bronze insert in camshaft

Post by bop » Fri Feb 08, 2019 11:53 pm

Thanks for your reply Graham. The only disagreement from me is that the cam sits in a babbitt removeable bearing shell, hence no metal to metal contact, which the bronze (not 100
% positive it is bronze) insert would chew up very quickly. This is a puzzler for sure! :?
Cam is now in engine and rebuild is nearing completion.
thanks again Bob

ranald
Posts: 262
Joined: Sat Feb 13, 2016 8:21 am
Location: North Wales

Re: Bronze insert in camshaft

Post by ranald » Sat Feb 09, 2019 8:52 am

Hello, I'm not sure what it is called. I would have thought that it allows oil to spread evenly over the surface of the bearing. Is there a hole drilled through the bearing to allow oil to pass through on its way up o the cylinder head? My Lanchester 15/18 has this arrangement. I had the camshaft reconditioned and attach a photo. My car had suffered from poor oil pressure in the cylinder head and it turned out to be blockages in this very area, so from experience...be very careful to ensure everything is clear. My car also has a ball and spring arrangement just as the oil leaves the block and before it enters the external pipe taking it to the head. This stops oil from draining back down.
66 Camshaft (reconditioned by Newman) (1).JPG
All the best, Ranald

bop
Posts: 95
Joined: Mon Feb 15, 2016 3:26 am
Location: Alberta Canada

Re: Bronze insert in camshaft

Post by bop » Sun Feb 10, 2019 12:54 am

Hi Ranald,
On my cam the insert is flush with the bearing surface. I suppose that maybe with it laying across the bearing there is a minute difference which would be enough to spread the oil film across the surface??? There are 2 holes in the Babbitt shell. One is the oil supply to the cam Babbitt bearing from the main crank bearing. The other is an outlet to feed the cylinder head. The engine was partially disassembled when I got it, but there is no evidence of a ball and spring or any other check mechanism on the passage to the head. I hope to install the head onto the motor in the next couple of days, When I do, I will have a closer look. Do you remember if the insert was bronze? Looks like they did a nice job reconditioning your cam! :)
thanks Bob

ranald
Posts: 262
Joined: Sat Feb 13, 2016 8:21 am
Location: North Wales

Re: Bronze insert in camshaft

Post by ranald » Sun Feb 10, 2019 9:25 am

Hi Bob, We could do with a Daimler 15 owner contributing to this post. I don't recall a bronze insert in my camshaft rear bearing. You haven't mentioned if the bearing on your camshaft has an oil feed hole drilled through it. I attach another photo of my Lanchester camshaft which shows the hole more clearly than my earlier photo.
27 Rear of camshaft with key as sent to Newmans.JPG
All the best, Ranald

bop
Posts: 95
Joined: Mon Feb 15, 2016 3:26 am
Location: Alberta Canada

Re: Bronze insert in camshaft

Post by bop » Sun Feb 10, 2019 5:07 pm

Morning Ranald,
Now you've done it! :) I was so intrigued with the insert I forgot about the machined slot and hole in that end of the cam. I also assumed that I would have had a quick answer to my question.
Below is a photo of the slot with the drilled hole. When I cleaned the cam and blew air into this hole it appeared to be dead ended so I didn't see an importance to it and thus left it as found.
6.JPG
Also the end of the cam has an ident which again appeared dead ended and I again assumed was just a machining point to center cam. Every cam I have ever dealt with is just a solid piece of steel machined to the desired profile!!
13.JPG
The photo below shows the rear babbitt bearing (photo shot at about 45 degree angle). The hole you see is where the supply oil from bottom end comes out and the arrow is approximately where the exit hole to supply the head is.
7.JPG
If oil enters your cam through the feed hole, where does it exit? Also what is the purpose of the slot? Perhaps to ensure adequate supply of oil to feed hole? And lastly if the oil path is through the supply hole and out the end of the cam, could the insert have been used as a cover that allowed a check valve mechanism to be inserted?? More questions then answers, so I think the cam has to come out again! :?

thanks Bob

ranald
Posts: 262
Joined: Sat Feb 13, 2016 8:21 am
Location: North Wales

Re: Bronze insert in camshaft

Post by ranald » Sun Feb 10, 2019 6:55 pm

Hello Bob, I'm almost sure you will find the hole through the bearing is blocked and needs cleaning out. In my engine, as the camshaft rotates, the entry hole, drilling and exit hole align every 180 degrees of rotation and thus oil is pressure fed up to the cylinder head. I agree, the indent on the end is probably related to the manufacturing process. The slot, I guess, helps lubricate the bearing and promote oil flow through the drilling.

I notice in your photo of the rear babbitt bearing that the arrow indicating the exit hole doesn't seem to be exactly opposite the oil feed from the bottom of the engine. Either your arrow isn't pointing accurately or the Daimler 15 arrangement isn't the same as the Lanchester 15/18!

I look forward to hearing further from you (+ perhaps a Daimler 15 owner!). I believe the LA10 is closely related, so maybe an LA10 owner will comment. We still don't have an answer to your original question concerning the bronze insert.


All the best, Ranald

bop
Posts: 95
Joined: Mon Feb 15, 2016 3:26 am
Location: Alberta Canada

Re: Bronze insert in camshaft

Post by bop » Mon Feb 11, 2019 1:04 am

Hi Ranald,
Took the cam out and had a real good look at it. Boy my memory is bad because I put the cam in only 2 weeks ago. :o This is what I found
1. There is no insert in the cam. It is a machined groove. Even though I originally washed it in Varsol, I guess this area was stained by dirty oil and was not polished like the rest of the bearing surface, only when I rubbed it with steel wool did the stain start to disappear. Strike one!
21.JPG
2. The cam hole is drilled staight through and was clean. Strike two!
23.JPG
3. The oil supply to babbitt bearing (white arrow) and exit from the bearing (red arrow) to the head are not straight through. The red arrow is pointing to the banjo fitting that attaches to the oil feed tube to the head.
20.JPG

I guess that slot (insert) is there to help lubricate the bearing surface! That was almost strike three!

thanks for the help Ranald. Nice to kick around ideas. :)
Bob

ranald
Posts: 262
Joined: Sat Feb 13, 2016 8:21 am
Location: North Wales

Re: Bronze insert in camshaft

Post by ranald » Mon Feb 11, 2019 8:37 am

i’m glad you are sorted. I’ve just noticed that you have been running a parallel thread on the Daimler forum so that is why no Daimler owners commented on this thread. I tend to look at ‘Active Topics’ and don’t take any note of the sub forum. Good luck with the rest of the engine assembly. Keep us informed. Ranald

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