Straight 8 camshaft bearing

[58tailfins]

Hi there

i have a straight eight who needs some new camshaft bearings

and the question is,can i do it my self ,or is it recomended to

have a machine shop do it for me ,

i would like to hear from someone who tryed it,

thank you

Bjorn

[Patrick W. Brooks]

Hello Bjorn: Have installed these bearings at least four times and it is trickey. A long handled driver with a proper sized driver end piece is required to remove the old bearings and install the new. Anything else will damage them. Installing them also involves the danger of damage to one of the bearings and this has happened to me. The supplier provided another at no cost but experience and the proper equipment is ablsolutely necessary in my opinion. I rebuilt my engines in the shop of a professional rebuilder who is a friend and has all the equipment, including a crank grinder and mill for heads etc. Sometimes there is no substitute for experience and the proper equipment. Hope this helps. Patrick W. Brooks, BCA #3939

[58tailfins]

thanks Patrick

the reason why the bearings should be changed is that, i have bought a NOS engine block and there is new bearings installed, but is says in the shop manual

that bearings must be line reamed to fit the camshaft,and it is of my knowlegde

if i bought new replacement bearings, it would not be neassary line ream them

because the accucary of the replacement bearings are better, do you know if that is true , have you reamed your bearings when you installed them , where they replacement or Nos Bearings .

anyone feel free to give some comments about this

thanks Bjorn

[37sedan_mod47]

Just a thought, but it might be less money to have your NOS block's bearings line reamed than it would be to buy new bearings. I used to be an automotive machinist, but that was almost 20 years ago, so I couldn't tell you what it would cost today, but my guess is about $75 here in the USA. An installation tool alone would probably cost as much. I look at it this way, if the factory installed bearings have to be line reamed, then you know it is critical to get modern replacements in correctly. I used to do it and I am having my cam bearings replaced at my local machine shop because they have the proper equipment to do it right the first time.

[Patrick W. Brooks]

Hello Bjorn: I have never bought a new block, and therefore, do not know if the bearings installed when it was assembled require any reaming. First, slip your camshaft in and see how it feels. If it turns easily it probably is not necessary to ream. Remember your camshaft is used and will have some small amount of wear so this may mean reaming is not necessary. A machine shop can measure the camshaft OD (outside diameter) and ID ( inside diameter) of

the bearings and this should give you an idea as well. An experienced engine rebuilder should be able to tell if the camshaft is to tight by simply spinning it after it is installed. I have always bought new bearings and installed them in my old block and have never had a problem of any kind. Be careful in sliding the camshaft in as it can ding a bearing and create a problem. Use engine prelube (an engine assembly lubricant)oil can also be used but prelube is better. Prelube is best as the engine will not have oil to the moving parts right away as the oil pump is not primed. Remember to pack the oil pump with vasoline to create a vacumn so that the pump is primed quickly. The vasoline will be quickly melted by the heat from the oil and hurt nothing. Keep in touch. Patrick W. Brooks

[58tailfins]

thanks both for your opinions

im not very expericended in rebuilding engines so maybe i should

find a machine shop to do the camshaft for me dont want to ruin

anything ,and thanks for the trick about the oil pump

its important to have the bearings lubricated as soon as possible

more tricks like that would be apricated

Bjorn

[Patrick W. Brooks]

Hello Bjorn: Have been thinking further about your question and stopped to talk with my motorheard friends at the engine rebuilding company where I often work on engines. We all agree that the cam bearings should not require any reaming. I have only had experience with some rod/pin bearings requiring reaming. I cannot look at what you have to read about this but think it very unlikely there would be a problem. If you slide the camshaft into the block and can turn it without much effort with a small wrench you should have no problems. If you need to install different cam bearings you need help in my opinion. Hope this helps. Patrick W. Brooks

[The Old Guy]

I don't know how they built the straight 8, but the Chevrolet 6 from the 50s had semi finished cam bearings. They finished them when they finished the main bearings to make sure that they had the proper distance between them. I always wondered why they did it that way,as the poor guy that had to rebuild it did not have the same equipment available, and was left with whatever the original clearance in the block was. This engine had no timing chain, and I assume it was to keep the gear mesh perfect.

[58tailfins]

Thank you guys you have been really helpfull

Bjorn

[Guest imported_PackardV8]

i am not familiar with the Buick streight 8. However be advised that some engine manufactureres (but not all) use progressively smaller cam bearing ID's from front to rear. Measure the journals on your cam with a micrometer to determine if this is the case and advise the shop should u happen to have it outsourced. You can also measure the existing cam bearing ID's.