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cam bearings

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Deleted member 21878

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i had new cam bearings put in my block after it's bath. i read somewhere that you should have the bearings reamed after installation to fit the cam. called a shop and they said the bearings are finished and do not need reaming... which sort of make sense.

how are these installed?
 

roscoe

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You need to have them clarify what they did to install them in a "finished" condition. The book says that the bearings, they are actually bushings that are press fit into the bores, need to be reamed in line to .001 to .002" of clearance for the camshaft. If they did not ream or broach the raw bearings I don't know how they could install a new set and end up with them being within that tolerance.
 
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Did you give them the cam at the same time you took the block in to have the bearings fitted? If not, then they only did half the job.

You can try test-fitting your cam to be sure, but I'd be very surprised if a) you can get it all the way in** and b) if it will rotate freely.




**WARNING: DO NOT let the cam go any further into the block than if the engine backplate was in place; to do so will run the #6 exhaust cam lobe into the bearing and gouge the soft surface. Cam bearings/journals get smaller the further into the block they are, and the rearmost one is smaller the base-circle of the cam.
 
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the guy at the machine shop i used said before we started he did not have a way to ream the bearings. i was hoping i could get the shaft in. i could not.

So i called the Healey Surgeons about getting the bearings reamed. they said they do not do that. their machine shop does it and i should go back to my shop. i explained he did not have the ream and it did not make sense for him to buy for just this. could i call their machine shop. they told me who it was and i called the guy there. he said he does not ream them. he does not even have a ream for it. he said the most he has to do is clean up any burrs at the split. the bearings he gets from the healey surgeons are finished. once he cleans the burrs, the shaft slides right in. he was betting that was my issue. i have not really checked this out as i have the block taped up so i could paint it. wanted to get a coat or two on before the rust gets started.
 

steveg

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the guy at the machine shop i used said before we started he did not have a way to ream the bearings. i was hoping i could get the shaft in. i could not.

So i called the Healey Surgeons about getting the bearings reamed. they said they do not do that. their machine shop does it and i should go back to my shop. i explained he did not have the ream and it did not make sense for him to buy for just this. could i call their machine shop. they told me who it was and i called the guy there. he said he does not ream them. he does not even have a ream for it. he said the most he has to do is clean up any burrs at the split. the bearings he gets from the healey surgeons are finished. once he cleans the burrs, the shaft slides right in. he was betting that was my issue. i have not really checked this out as i have the block taped up so i could paint it. wanted to get a coat or two on before the rust gets started.

Hopefully you're taking your block there for the machinist to fit the cam. I'd want his blessing on it.

My mechanic painted the inside crankcase with a type of red paint BMC used to use to aid in heat dissipation or oil drainage. You might want to research that. No further info - that's only what he told me.
 

dougie

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Hopefully you're taking your block there for the machinist to fit the cam. I'd want his blessing on it.

My mechanic painted the inside crankcase with a type of red paint BMC used to use to aid in heat dissipation or oil drainage. You might want to research that. No further info - that's only what he told me.

I think you were referencing Glypatal, https://www.eastwood.com/glyptal-red-brush-on-1-qt.html
 

Michael Oritt

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I wonder if Glyptal would seal up porous aluminum against oil seepage? The sump on the Climax engine in my Elva MK IV will literally sweat engine oil.
 

Brinkerhoff

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Your machinist is correct ! The front end cam bearing has a parting line that raises slightly when pressed into the block and needs a slight working in by hand ( directly at the parting line of the shell) with 600 grit and some Marvel Mystery oil . As you fit the lightly oiled cam into the block the area to be sanded down will appear shiny. Sand this area down in a rotational manner in and out with MM oil on the bearing. It takes some time , perhaps an hour or so of sanding lightly with oil , cleaning the grey residue off with a clean paper towel and then some aerosol brake cleaner , then trial fitting the camshaft again. You are just trying to sand the raised "shiny" down , nothing more. There is no magic "reamer" used. As long as the inner bearings are driven in carefully with the oil holes lined up , you'll be golden and the cam will eventually turn easily in the bearings without leaving a shiny spot on them . Clean thoroughly with paper towels and you're on to another step.
 
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I know people use Glyptal__electric motor insulating varnish__inside engines with good results, but that wasn't my experience. One of the engines I built for my car, sometime around the early-mid 1980s, I'd had a block "tanked" took it home and thoroughly washed it before applying aerosol Glyptal.

All the assembly work went as planned, and when I drained the oil after some period of use (100 miles? 1000 miles?) and could see flecks of the stuff in the oil. That was nothing compared to the amount of it packed into the spin-on oil filter; the filter had to be bypassing most of the oil!

The engine came back out, and the bearings were inspected__all good__and what little Glyptal remained was easily stripped and the engine buttoned back up.

You can do what, but that put an end to me using the stuff on any of my work.
 

dougie

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I know people use Glyptal__electric motor insulating varnish__inside engines with good results, but that wasn't my experience. One of the engines I built for my car, sometime around the early-mid 1980s, I'd had a block "tanked" took it home and thoroughly washed it before applying aerosol Glyptal.

All the assembly work went as planned, and when I drained the oil after some period of use (100 miles? 1000 miles?) and could see flecks of the stuff in the oil. That was nothing compared to the amount of it packed into the spin-on oil filter; the filter had to be bypassing most of the oil!

The engine came back out, and the bearings were inspected__all good__and what little Glyptal remained was easily stripped and the engine buttoned back up.

You can do what, but that put an end to me using the stuff on any of my work.

Randy -

With 30 years in the coatings industry, I've learned never use anything out of an aerosal you want to last. The material has to be reduced too much to transfer, lowering the volume solids and the performance of coating....FWIW
 
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I wonder if Glyptal would seal up porous aluminum against oil seepage? The sump on the Climax engine in my Elva MK IV will literally sweat engine oil.
Loctite has a solution for (weld) porosity; might work for you...

If you remind me enough, I'll remember to look at what "#" is on the bottle I have (it's their same solution you apply to assembled fasteners).

Another possibility__depending on how long you can be without the pan__is this oven-cured thermal dispersant that I use. It too is supposed to aid oil drain-back, with the added benefit of increasing the aluminum's ability to radiate heat away from itself. It's a metallic-ceramic compound and I could apply it inside/outside of the pan. If nothing else, it would have to sweat LESS oil ;) Only real criteria, as far as the pan is concerned, is that it doesn't have a cast-in windage tray, as preparation requires blasting with aluminum-oxide.
 
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brinkerhoff you were dead on... well almost. the first bearing did have a burr on it and was raised a little. took just one light sanding and i could put the cam in, front first, without issue. then i went to the back and put the back one in from the rear. it went in fine. but the third one turned out to be the problem child. 4 hours later, i think it feels pretty good.

of course part of the length in time is me being cautious. but part of it is that it is hard to get in to those middle bearings. i felt like i was having to push too hard with my finger. the oil makes the paper want to slide on my finger as well as the bearing. i ended up taping the paper to a 3/8 dowel that i cut about 3 inches longer than the bearing is wide. with that i was able to keep consistent light pressure and a circular motion.
the last time i pulled the cam out, i still had a shiny spot or two. but it was a wider shiny area. maybe a 1/4" wide and about 3/4" around the bearing. i figure this is just a high spot in the bearing. i would think the cam will wear it down more evenly than i will with paper. So i left it alone.

i can push the cam thru the block and turn it with the sprocket nut on it, by hand. it is tight but these are new bearings. i would think they need to wear in some. it turns consistently without the feeling of any binding. after the last time i took it out, i cleaned it one more time with brake cleaner and oiled it with assembly lube.
 

bob hughes

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When I rebuilt my engine, the cam bearings were pulled in one by one by a clever length of steel shaped for the job and the bearings did not require reaming or fettling at all. Just used some assembly lube and shoved the cam in - works a treat.

:cheers:

Bob
 
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i can imagine split bearings are a pain to get in. also sure it helps to have someone who has done it a few times.
 

dancrim

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Harley Davidson has used Glyptal on the inside of their Alum. motor cases since the beginning of time. Never a problem.
The surface has to be super Clean and the Glyptal is sprayed on in a light coat. Old oil soaked aluminum is hard to
clean as it is so porous. I am not sure on cast iron, as far as if oil film will seep through it .
 

Healey Nut

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Glyptal works and so does red oxide primer I’ve been told.

The engine blocks on my 64 and my 67 were red oxide inside and was all intact when I overhauled the engines .
I would use the red oxide over glyptal as the red oxide would soak into the cast better . Glyptal is thick n goopy and will just sit on the surface .
Also the red oxide is solvent based so you wont have to get it super clean to get it to bond to the cast .
 
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