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  #16 (permalink)  
Old 04-20-2012, 08:56 PM
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Forgot to mention, your guy is right- many manufacturers will use crank bearings +/- several tenths from standard when building a new engine. They fit the bearing to the journal, not the journal to the bearing in other words. So on a new production crank, there could be problems if "standard" bearings were used w/o first measuring the journals.

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Old 04-21-2012, 05:30 PM
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I have read soooo much. And sometimes feel that I am realy well informed. Now, I am humbled and also inspired. The older fellow said "it's just a challenge". I have so much respect for the guys hotroddin or rebuilding successfully in the 50's and 60's. They are responsible for so much unpaid R&D. I am happy to see the other side. There are so many variables and I have come to find out that you have errors and then epiphanies. He said and I believe it... "when you have these problems you never forget". You've spent your last dime and all of the thought... then it fails. That's part of hotroddin I guess. I just wanna do it right and make it last. Thanks so much for all of any or you guys's input. I was so dissapointed bc I have 2 cars down right now bc of this. I am going to get to the bottom of it and when I do I want to tell everyone what happened to correct so others don't stay down for half of a year scared to buy more parts knowing it's going to fail again. Have a good weekend guys and I'll be talking again soon if you are interested. Does anyone else know of people having these problems?

Nate
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Old 04-21-2012, 06:27 PM
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Nate, speaking only for myself, this is the first time a loose cam bearing condition has come up. I've (as I think I mentioned before) have had tight Pontiac cam bearings that had to be clearanced in situ, but not loose bearings.

I'm sure I'm not the only one following this, so yes, by all means update as you go forward. And thanks for doing that this far, too.

"Errors and then epiphanies" would make a good chapter in a book on engine building!
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Old 04-22-2012, 07:59 AM
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I've also never seen a "loose" Pontiac cam bearing (in a factory block, that is), and I've seen a "few" Pontiacs...(:-

The DuraBond cam bearting tool, considered the BEST available, is just as you describe. An expandable inner ring with a "rubber collar". The metal ones are "old school" and used for tear-down in most shops today (those that still have them). Of course, in the proper hands, they still "work". We've found, if over-tightening the bearing to the tool, it WILL distort it and cause problems installing the cam. Just enough tension to keep it "in place" and not so "loose" it would drive the tool "through" the bearing is called for.

Jim
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Old 04-25-2012, 02:09 PM
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I feel ya. That is something that I wasn't getting right off. I thought people meant cutting on the cam journals when they would mention honing. I didn't concider cutting the bearing it's self until I talked to him the other day but hadn't mentioned that yet on here. But good point and now I gotchya.
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Old 04-25-2012, 02:47 PM
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Ok, this is nearly embarassing. It's not as bad as it could be (on my cred lol). The 2 things that the older engine builder had concern with but wouldn't condem right off as a problem.

1. He used an instalation tool that was metal on the end that the bearing sits on as it's driven into the block. Mine cam bearing tool is a universal. So, I have 5 different sizes to choose from. They expand as you tighten a bolt that wedges apart and gets a firm hold on the bearing. Well, The part which expands is metal but there is a rubber sleeve around it vs. the all metal tool.

2. He didn't like seeing .006" "crush".

Ok, I thought about it all day after the measuring went down. He has confirmed that I have a suitable bearing for my application as well as the journal size that it's suposed to have.

I ended up bing *** backwards. He said they are crushing too much. Eventhough that was OD, I know that the ID has to be decreasing by too much aswell.

Yesterday, I thought wait a minuit. I thought these things were loose but he is saying that they are auctualy smaller than they should be after instalation. I thought damn, he said (with a removed bearing that I installed in his hand) I bet I could put this into your engine with my hand. Then he did get it started but that was his point. The bearing crushed so much it could likely end up spinning. I'm hoping like hell that none are spun in my 400. This 455 I'm on I only tore down to prevent failure since I put the same cam/bearings that I did in my 400 in it..... dang it!

Here's where I'm at now. That cam tool is ****. The rubber that contacts the bearing and is giving. A professional tool with a metal driving end will have to be a pretty close fit and also isn't going to give like rubber thus holding my crush to a less dramatic shrinkage. It sounds good and i'm sticking with it lol Well I ordered the tool last night. Had a few beers and went through with.

I know clevite is selling these bearings to alot of people. As a matter of fact you have to try to find another co. on google. With that, my Summit cams have the same bearing diameter as the factory cam. He confirmed that my block and bearings were appropriate. So, I think my universal cam bearing tool is junk. When I picked up that bearing that he started in by hand and put it on my cam I about ****. It barely went on! Too tight. You guys are right on by letting me know that you never heard of a pontiac having too loose of bearings. I had no idea that a cam bearing crushed when I drove them in. Hindsight..... Anyway, even when I was told by a couple of guys that they will crush I though there was no way it's going to get that much smaller. What I was guessing in my mind is that there must be like .015" or so when I tried the new out of the box bearing on the cam in my hands. That estimation of .015 was bs (aparently I havn't had enogh time with dial indicators, calipers and mics).

Now, waiting on the tool to come and ordering another box of bearings. I think alot of people just swap the cam not bearings and leave the distributor drive gear marks. I wish I would have but wanted to do things as right as I could to not have to teardown later. My current thinking is that that gear is going to scratch new bearings too on the way in. You just won't see it since the cam is now covering. It's just hotrodding man. You gotta learn some stuff the hard way and hope like hell somebody like George stops by and lets you know all of his hard earned secrets. I know it's a book but I wanted to let it all out. Rookie mistake by not using the right tool for the job. And by the way the damn professional quality tool..... is like 2/3 the price of that universal I sprung for
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  #22 (permalink)  
Old 04-25-2012, 03:28 PM
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Hmmmhhh
I love my universal cam bearing tool.
I have 3 tools. An old, old all steel tool that has about 75 different cam bearing drivers. A old universal tool and a almost new version, both of which use the expanding rubber arbor concept, the diff being that the new tool has 6 wedges contained by the rubber and the old one has 4. The new one works better.
The universal tools seem to make getting the bearings in easier without damage.
I never beat a bearing in without some lubricant. I like Zep 45, but it by the case.
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Old 04-26-2012, 03:52 PM
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Oh hell.... Well maybe it's my technique somehow. It's worth it to me to buy the tool and eliminate a variable. The ole engine builder guy says he will assist me if I want him to. He said I may have somehow damaged/distorted the bearings on the way in but the only one that the cone isn't used for is the last one so, I think they went in straight. Ofcourse, I still have a problem. If the tool is my issue, what would they be doing selling them right? I thought of that too. If it didn't work, they wouldn't be able to market them successfuly. One thing that I thought was good was that the adaptor that I had to use fit fairly snugly beforer I expanded it. Something I recall is that I didn't torque the bolt on the expander verry hard. There is no flat for a wrench so I held the handle and tightened about as tight as possible that way.

I'm not counting my chickens before they hatch since I'm no stranger to dissappointment so far. Thank you for the input though. The more I know the better off I am. So, here is another thing for me to concider.

Oh, what all is involved in honing bearings? That seems to be my next step if the new tool is no help. Still it's a way out and it would probably be more true after being cut right?
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  #24 (permalink)  
Old 04-26-2012, 04:36 PM
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Quote:
Originally Posted by ztwntyn8
Oh, what all is involved in honing bearings? That seems to be my next step if the new tool is no help.
The way I've done this in the past looks crude, but I've never had a failure...

I insert a cam and spin it so the bearings will have shiny witness marks where the bearings are tight. Then I take a bearing knife (three sided scraper tool) to clearance them in small increments until the cam spins freely.

You need good lighting that you can adjust/use w.o holding it- you want both hands free. Take your time. I recommend getting a tool, not using something else. Don't use sandpaper, the grit left behind is not good for the engine. If you want to polish the bearings, use a scotch pad.

I have heard about using an old cam w/cuts made across the journals to be used a a reamer, but have not tried this. Then there's the machine shop.

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Old 04-26-2012, 04:54 PM
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Every shop has cam "reamers" hanging around. By cutting "flutes" (of sorts) in the end journal, one can accurately "ream" a cam bore. Cams don't "bend"... (they break!)

455 blocks seem to have more issues with cam bores than 400s. I believe the added stroke really "works" the block, even in a "big car" application. Most 421s and 428s (4") stroke) I've seen were okay.

Jim
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Old 05-05-2012, 11:37 AM
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Universal tool...

I'm finding that it's probably not the instal tool that was bad or half ***. I'm think ing that the tool that was not used properly. lol After we talked about how long you have had your universal tool for a long time now. That made mo go be back to me beeing the tool that was used incorrectly.

I looked over all of my instructions and if fine pring it said note: If you have a bearing wall of .065" or less use this rubber adapter and if you havae a .900 or more you must use the less thick adaptor. Well, I'm thinking I've used the wrong rubber adaptor.
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Old 06-26-2012, 04:58 PM
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Here is a quote I found and think the last few of yall are right.

Getting the bearings in is the easy part. Fitting the cam is a different story as the bores in the block are not all in a alignment. This is due to a number of things, such as a 30 year old block has had some movement, but most of all when the factory drilled the block for the cam, the did it partially from the front, and then the rest from the back. As you can guess they never lined up even when new.

Use a proper bearing install tool as you do not crush the edges. Once you have them installed with the oil holes lining up and making sure they are not cocked to one side, install the cam dry. You may feel resistance, but do not force. If it will not go into a bearing, get out some 80grit emery cloth and carefully sand the leading edge of the bearing with resistance. Once you have the cam in, it should rotate easily by hand. If you cannot, move it back and forth a bit and then remove. Check the bearings. Shiny spots are high points and need to be sanded for clearance. Once you have a good fit, remove and put some engine oil on the cam and set back in and verify the final feel. you should be able to turn using 2 ringers. Now you are ready for final wash of the block.

Pontiac's are a *** for this, and I recommend any novice to have the machine shop install them. I would say 30% of first time builders will mess this up and have a spun cam bearing that will require a complete tear-down all over again. You may be able to find a shop with a flat rate to install, however most charge by the hour that know Pontiac's take anywhere from 2 - 8 hr just to fit the cam shaft.

Think of what you are spending to build your motor. Is it worth the risk?


Read more: http://forums.highperformancepontiac...#ixzz1ywTdjYek

My front most bearing I couldn't even enter. Took it out and it fit the rest nicely imo and turned realy freely. I just need to the the front bearing squared away and I may have it. The others seem to have slight rub marks too. I'll be glad when I learn and this is over.
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Old 06-27-2012, 04:07 PM
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The other thing I did is use my installation tool differently this time. There were 2 different sets of rubbers for each adapter size. One for bearings with a certain bearing wall thickness and less and for another size thickness and thicker. In all other instances I used the wrong one. This time I used the other, thinner rubber for the adapter. I think all of the bearings that I installed (except for the front most bearing) are good to go now. I could have went in crooked or something on the front bearing since I had no hole to place the cone in that centers the tool. That's where I'm at now. I suppose honing may be in my future.
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  #29 (permalink)  
Old 06-29-2012, 10:09 AM
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A little tip--

Put the rear three bearings in driving them in from the front of the block, then turn the block around and put the front two bearings in driving from the rear of the block. That way you can always use an alignment cone or arbor to insure they are in straight.

That's how a machinist/shop does it
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Old 06-30-2012, 10:13 AM
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There are several ways to "skin this cat". Which installation tolol you're using makes a difference in the process.

First and foremost, who ever told you Pontiac takes "hours" to put cam bearings in, should be avoided at all cost in the future. Having installed cam bearings in literally hundreds of ALL types of engines, mostly American V-8s, I can say with "authority", Pontiacs are among the least "troublesome". From their "era", in particular. Ford FEs, BBCs and Buicks come to mind as "problem children". Ford "Y-block" is THE WORST... It takes, literally, about 15 minutes to install cam bearings in ANY V-8, and IF things go "well", they present no issue. About 95% go without issue. The Pontiacs that HAVE given me trouble were nearly always 455s that had been over-heated in their previous "life". MAYBE 5 blocks in 10 years have "fought".

Blocks that have the same bearing in every bore are "through bored" (in one operation). Pontiacs and Ford 385s (Lima) are two I know of. Most are, as described, bored from each end, "meeting" in the middle.

We always install them from the front, all 5 positions. "Floating" the front one (no centering cone) is the method I was taught 40 years ago. Still works for me. Takes "practice", though. Perhaps the front one is better installed from the rear in this case. Take care not to gouge the other bearings as you put the tool in.

FWIW

Jim
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