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Drivetrain => The Nailhead => Topic started by: 35chevcoupe on June 16, 2018, 10:13:45 PM
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Has anyone ever installed their own camshaft bearings when rebuilding a nailhead ?
I,m just curious because i,m having a terrible time with the cam binding and having to remove high spots in the bearings themselves .
I,ve installed cam bearings on almost all my engine rebuilds and NEVER run into this much of a problem .
And if u had the a machine shop install them for you how did the cam go in and turn , was it easy to turn by hand ?
Do these engine blocks have that much core shift ? :icon_scratch:
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Which nailhead?
Call Russ Martin at Centerville auto Repair.
http://centervilleautorepair.com (http://centervilleautorepair.com)
530-272-1564
Post the results.
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I had the machine shop install my cam bearings, and the cam didn't fit properly.
Apparently that's common.
I used an old cam, cut a notch in each journal to act as a cutter, and used it to shave some material from the bearings.
An alternative is to polish the cam journal until it fits.
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The machine shop installed mine and the cam fit fine.
Chuck
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Same here on two nailheads.
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Walt , that is one of the methods of fixing the problem that I've heard about . I,m just afraid to remove that much material but maybe it doesn,t matter cause one way or another the cam has to fit in there .
Chuck , Jim , So when the shop installed the cam bearings in your block did they have a cam to try in the block after they installed the bearings ?
or did you guys install the cam after they installed the bearings ?
I,m just curious if your machine shops installed them and then had to ream or remove high spots in the bearings to get the cam to fit .
Thanks guys for the input .
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I built my first Nailhead in 1979 when I was a teenager! The shop installed the bearings, then (I was told) they had to 'align hone' them for cam fit. I don't know what method they actually used.
For the 401 i did in 2009, I used the cutter. I did call the manufacturer of the bearings, Durabond, and tech support said it was ok to remove the excess material. He did give me some numbers as to how much could be removed, but I don't recall the figures.
Doc also uses the cutter method. It would be good to hear what method Russ and Tom use.
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Come to think of it, John, I did give the machine shop my cam to test fit. But I believe it fit and they didn't have to make any adjustments.
Chuck
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Walt , I have been in contact with Tom T. and he tries to ONLY remove the high spots of the bearings . That way you don,t increase the whole bearing tolerance . I have been using his idea but ( at least on the block I have ) it is very time consuming and not the easiest access .
Maybe some of these blocks are better than others . The one i,m doing currently is a 425 .
Chuck you must have a nice straight block as I,m being told that this is a VERY common problem .
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I had this issue with my 425 and I talked to Carmen. He said to remove a little from the the high spots carefully across the plane with a pocket knife, scotch brite it and re-fit until it does not disturb the scotch brighted area: Ran, runs fine. It did take some time and patience though.
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From the Centerville website
The hardest part of a Nailhead rebuild, Martin explains, is installing the cam bearings so he leaves the hard work to someone else. "I have the machine shop install mine. Always have an old cam for them to use to fit the bearing, and after you get it home make sure they are installed with the oiling holes lined up and MAKE SURE THE FRONT BEARING IS IN CORRECTLY. This is a common mistake and is a real pain to fix after the engine is in the car. If it goes in wrong you won't get oil to both lifter galleys. Another common mistake to watch out for is leaving out the plugs in the oil galley behind the distributor."
Recommend giving Russ and Matt a call.
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Well , the cam bearings are all in . I have to say this is BY FAR the toughest set of cam bearings I have ever installed . I did have to remove some bearing material from # 2, 3 and 4 cam bearings but I only removed it from the high spots .
Using an old cam I slid it in and turned it slightly just enough to make a mark on the bearings one at a time , then using a knife removed just enough lead to get the cam to slide in . I used a small piece of red scotch brite pad to smoothen out any rough edges left by the knife edge .
I really hated doing it this way but it was pretty unanimous by everyone i talked to that thats the way its done .
It only took me 6 hours :angry5:
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John,
So the rest of the build will be smooth like butter. Right?!
Mark
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Mark ,
That would be great . But I did run into another small snag already . I had the rotating assembly balanced and because the forged pistons are heavier than the stock pistons they have to add weight to the crank . So they welded a chunk of heavy metal on the crank flange and when i tried to rotate the crank it hit the back of the block , it wasn,t much so I just ground an 1/8 inch off the back of the block .
SO hopefully now I can proceed WITHOUT anymore surprises . :icon_scratch:
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My crank was similar there as well. I had to grind the block a little like you. They called it a sail. I also had to have the Flywheel bolts that were listed for the car cut down as they would catch on the block.
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I take an old camshaft, cut a diagonal slot across each bearing journal with a cut off tool then installed it and turned it a few times to loosen up the new bearings. Its a permanent tool in my tool box now
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John,
We talked about the piston weights. Like I said my forged pistons, pins & rings have come up CONSISTENTLY lighter than stock. Make ABSOLUTLEY SURE the assembly was balanced correctly. I HAVE NEVER had to add weight!!!!
Tom T.
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John,
We talked about the piston weights. Like I said my forged pistons, pins & rings have come up CONSISTENTLY lighter than stock. Make ABSOLUTLEY SURE the assembly was balanced correctly. I HAVE NEVER had to add weight!!!!
Tom T.
Hi Tom , I did double check with the machine shop that he had the flywheel indexed on the crank correctly when he did the balancing .
as far as having to add weight to the crank there could be a couple things that could possibly made that happen . 1 is we put a different set of piston pins in them .He didn't like the fact that the pin fit was only at .0005 so I bought a set that had a .002 fit , so they may have made up for some of the extra weight . also the amount of weight he welded on was,t really that much , if you look at the photo close he removed weight from the last counter weight which would actually decrease the amount that was welded on .
I will admit the guy doing the work doesn't know a lot about nailheads but they've been doing race engines in the area for a long time . They also have a dyno service that they use every day , so we will be breaking the engine in there also .
Tom thanks again for making these pistons and setting me up with good parts .
Talk to you soon . :cheers2:
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John, what shop is doing your engine?
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Jim , it,s R&R Performance in Spring lake park .