LS1HIGHLIFE

iTrader: (8)

I had a bad cam bearing in the #1 position and decided to replace it with a new one. The motor is still in the car and I do have a cam bearing tool with a short handle to do this with. I went ahead and ordered a set of Dura-bond cam bearings from one of our sponsors. PN: CH-10.


I grabbed the #1 bearing and tried to install it..... no avail, It wasn't going in. I thought it was because of how cold it was around here and the block had contracted a smidge. I tried #5 bearing and the same thing.

I got out my calipers and checked the I.D. and O.D. of the old bearing and each of the new ones. Here is what I discovered:

Old - I.D. 2.175" O.D. 2.327"

New #1 - I.D. "" O.D. 2.334"
#2 - I.D. "" O.D. 2.325"
#3 - I.D. "" O.D. 2.317"
#4 - I.D. "" O.D. 2.324"
#5 - I.D. "" O.D. 2.336"

The Dura-bonds I received are a bit too big (.008" - .010"). Not even pounding the **** out of them will work.....

Has any one else had a quality control issue with bearing manufacturers?

Car info:

2000 Z28, stock bottom end, new top. (so early block with smaller journals 1st Housing Bore: 2.3260 5th Housing Bore: 2.3280)

JRENIGAR

iTrader: (37)

Call me crazy but the #5 bearing should go being its .001" smaller than what you removed according to your measurements. Maybe you could use a small propane torch and heat the block around the outside of the bearing area to expand it enough to get it in. I would also put the #5 bearing in the freezer for an hour or so right before installing it. This should be all you need to make the #5 bearing fit. How did you remove the bad one?

LS1HIGHLIFE

iTrader: (8)

Your crazy! #5 is .009" larger. I've tried the freezer trick, but hey are still to big. #s 2,3,4 are too small and they just slide right in.

BRUTL

iTrader: (27)

He shouldnt have to make the wrong bearings work in a different hole. I would get in touch with the vendor and see what they have to say.

JRENIGAR

iTrader: (37)

Whew, I been at work all night. Im normally pretty good at math but not when Im . My bad.

RezinTexas

Are the new bearings perfectly round? I've had problems trying to measure the OD of loose cam bearings, as they tend to be slightly out-of-round.

I would get some fine-grit sandpaper and remove some material from the OD of the new bearing, that should get you to where you need to be.

BRUTL

iTrader: (27)

man, why dont you tell us how you really feel, because the email I got when you originally replied said you wrote "Then you can't measure worth a crap!"

Before you call someone out on wrong math, you double and triple check your own, at work all night or not.

LS1HIGHLIFE

iTrader: (8)

You are correct Rezin. All of them are not perfectly round. I took measurements at the 12-6 o'clock 3-9o'clock and so on. They all seemed to be within .0025 of the various measurement positions.

I will try working with the vendor first as this seems to be a QC issue from the manufacturer. If that yields the same results then I may try the emory cloth. I'm a little Leary of that though....

KCS

iTrader: (20)

Instead of measuring your old bearing, look up the specs for what the bearing should measure.

The CH-10 bearings are three different sizes which is why the OD's seem to be in .010" increments. The housing bores are the same way.

Are you doing this with the engine in the car?

Cam installation tools have a cone which ensures the bearing goes in straight and not crooked or cocked. If you're doing this in your car and you're swapping the front bearing, how are you making sure the bearing goes in square?

LS1HIGHLIFE

iTrader: (8)

I have measured the bore diameter also. It's 2.326" making the bearing I took out fit perfectly. I'm doing this in the car so i do not have the ability to use the alignment cone. I know, it's not ideal, but I don't have the luxury of removing the block from the car.

JRENIGAR

iTrader: (37)

Who asked you? I was talking to the O.P. He obviously got the original and saw that I corrected it but didn't feel the need to call me out on it so

It'llrun

Get back to the supplier. You definitely don't want to force that fit.

KCS

iTrader: (20)

There should be more than .001" press fit. I put .003-.005" press fit in a valve seat insert. Sometimes it takes some good whacks to get the cam bearings in with the block on a stand so I don't think theres anything wrong besides the fact that the block is still in the car. I think "not ideal" might be an understatement.

LS1HIGHLIFE

iTrader: (8)

I will agree with you there. The #1 and #5 I received are between .008 - .010" too large. They just wont go in with any amount of whacking.

Yeah it does suck that the motor is in the car....... I have to deal with it and there is no way around that. If I had a new bearing with an O.D. of 2.328 - 2.332" I would be golden & on my way to putting this thing back together. I just couldn't risk leaving a bearing this beat up in the motor and causing any catastrophic issues down the road.

LS1HIGHLIFE

iTrader: (8)

Wow..... So I called the tech line at Dura-Bond and spoke with Allen. He said the measurements I have are correct and that the "GM guys" told them to leave that much in there. I asked him why, and he could not answer that.

.008" seems like a lot of extra material to me..... I can not beat that bearing hard enough to make that fit.

I guess I have to go with another company if that's how they operate.

RockinWs6

.008 press fit is insane, It obvious someone doesn't know what they doing. Anything over .003 is TOO FARKING MUCH!

I would make a jig and turn them to size OR try to find the proper sizes. If you press in a cam bearing .005 interference fit the cam journal fit is going to too tight.

LS1HIGHLIFE

iTrader: (8)

Yeah I just talked to a machinist buddy here and he's ordering me a set of Clevites in the morning. He stated that .001 - .003" at the most is all I need.

RockinWs6

I'm kinda curious about all this because I've read about it before. It seems GM has wrong info on these bearings. The is no such thing as a .010 press fit bearing, it just isn't possible. Gotta be some other explanation.

It'llrun

Indeed... .008 sounds really out there, unless they want a mess. It's a zero tolerance press, but that shouldn't mean you're cramming 10 lb of dirt into a 5 lb sack... I have no problem with Dura-Bond, but used Clevite for so long, I generally consider those right off and I'd think you could get a set today from NAPA. Maybe not... I quit building engines many moons ago.

RezinTexas

emory cloth will do it for you.

Plenty of people (myself included) do it to the ID of the bearing, so the OD should be no issue at all.