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Hey guys, hoping to get some insight from y'all.
I recently pulled the 455 out of my 67 CS so that I could convert the car over to a manual tranmission. I took the crank out so that it could be machined for the pilot bearing/input shaft. I was cleaning up the caps and bearings and noticed some wearing of the lower portion of the bearings. What do you think? I had the engine rebuilt about 9 years ago and has maybe 1500 miles on it. Would you reccomend replacing the bearings at this time, since its apart?
I am picking up the crank on Monday and will inspect the journals for wear here. I assume if I do see wearing on the journals I should have it addressed while at the shop.
Any feedback would be greatly appreciated.
Thanks
Drew
Last edited by DLaz70OLDS98; Jun 17, 2023 at 09:00 AM.
Did you measure anything to determine the bearing clearance you have ?
When you say "measure anything" I am assuming you mean the journals on the crank? If thats the case, no. I will be picking up the crank on Monday from the shop. If there are some other measurements I can take I am all ears.
If you're concerned you can get some Plastigauge to measure your bearing clearances. I'd call that wear normal for 1500 miles. Just use assembly lube and put it back together.
I dont like the fact that the thrust bearing has copper showing at 1500 miles. You need to properly check the main bearing clearances with a bore gauge. Plastigage is ok for a quick check but really not that accurate. Do you feel comfortable with the machine shop that is doing the crank for you ? Ask them if they will check it for you. If nothing else clean it up real good and put a new set of bearings in and torque the caps down and ask them to check it with a bore gauge and compare it to the crank size.
Most of the bearings look like there is not enough clearance.
I dont like the fact that the thrust bearing has copper showing at 1500 miles. You need to properly check the main bearing clearances with a bore gauge. Plastigage is ok for a quick check but really not that accurate. Do you feel comfortable with the machine shop that is doing the crank for you ? Ask them if they will check it for you. If nothing else clean it up real good and put a new set of bearings in and torque the caps down and ask them to check it with a bore gauge and compare it to the crank size.
Most of the bearings look like there is not enough clearance.
Take the bearings with you to show the machinist. You may want them to polish the crank while it's out. Then again a good shop would recognize rod/main surfaces that need work.
As mentioned, measure EVERYTHING twice!
Check the valve train after assembly. Proper geometry is critical for these engines.
Use the same thickness head gaskets. Check head and block deck surfaces with a calibrated straight edge(Starrett).
You have it this far apart I'd examine all bearing surfaces including the cam bearings. Look at cylinder cross hatch, cam to lifter surfaces et al.
How about valve guides, seats, and seals? Can't hurt to do a quick 1-2 valve lap & seal replacement....you are in it why cut corners?
Let the MAWs commence...
Last edited by droldsmorland; Jun 19, 2023 at 05:04 PM.
If you do have to machines the crank, make sure everything is machined on the loose side of the spec. Olds engines(especially ones you plan to beat on) like additional clearances.
Ok, so it took me some time but I was able to measure the main bearing journals and determine the current clearance. Below is what I was able to come up with.
1) The crank at some point in its life was ground down, I found "010" marked on the counterweight. When I measured the main bearing with the mic I came up with 2.9892 for journals 1-4 and 2.9949 for #5, which I believe confirms it was previously ground down.
2) The existing main and rod bearings are all .010 (all lower half of the bearings are showing signs of wear)
3) Main Bearing #1 = 0.0004 Clearance
Main Bearing #2 = 0.0003 Clearance
Main Bearing #3 = 0.0003 Clearance
Main Bearing #4 = 0.0003 Clearance
Unfortunately at the present time I am not able to measure #5 but I will. However, from what I am able to tell from the service manual all of these are well below the allowable clearance range of 0.0005 - 0.0021 (#1 -4) and 0.0020 - 0.0034 (#5). I also plan on measuring all the rod clearance as well but I wanted to provide this information.
Thanks
Drew
Drew,
That is definitely tight which explains the way the bearings were wearing. The #5 journal is also way too big, it should be the same as the others.
Drew,
That is definitely tight which explains the way the bearings were wearing. The #5 journal is also way too big, it should be the same as the others.
How are you measuring the clearance ?
I will go back and check the size of the #5 Journal again.
As far as measuring the clearance I followed these steps:
1) Measured the journal with a micrometer. Once I got the measurement I locked the micrometer
2) Set up my dial bore gauge the appropriate anvil. I used the micrometer to zero out the dial bore gauge.
3) Properly torqued down the main bearing cap to 120 ft/lbs with the bearing in place.
4) Finally I used the previously zeroed dial bore gauge to determine how much extra clearance I had.
I repeated each step for every main bearing, minus #5. Is this acceptable?
4) Finally I used the previously zeroed dial bore gauge to determine how much extra clearance I had.
I repeated each step for every main bearing, minus #5. Is this acceptable?
Perfect I am surprised it is tight considering the 1-4 journal sizes are actually at the minimum of the spec. Not sure what the fix is going to be. Getting a crank guy to grind just .001-.002 off the mains is tough. Most of them dont want to do it. Mine will but he grumbles about it What brand bearings are in it ?
Was this a stock rebuild or a performance parts build?
What was your oil pressure when hot and with what weight of oil?
My recommendation:
1. Take your block to the best machine shop you can find, same for the crank. Don’t worry about hurting feelings, it is your engine and your time and money.
2. Have the shop mic the crank and check it for alignment (see if it rides the V blocks without warp along the journals or the nose), have it checked for stroke and runout on the main journals and the rod journals to determine if it is radially true or non-concentric like an egg. Let the shop measure everything, hopefully they are using a properly set (on a fixture)Sunnen bore mic for the main housings and main bearings. Do not use your own measurements to tell the machinist your numbers.
3. Determine if the shop can turn it to correct the current condition of being too tight while still running a .010 under bearing, if not, move up to the .020
4. Purchase new main bearings in correct under size and take to the shop to have them torqued into the saddles.
I like the speed-pro 108M bearings with 1/2 groove
5. Have the crank ground to give you .003 clearance on the mains and .0025 on the rods and have enough side clearance on the rods to let the trapped oil out.
Have it checked for thrust clearance and make sure you have enough to not wipe the thrust bearing flange out, especially now going to a manual trans with the load that adds to the crank thrust
6. For improved oiling to the mains, you can run restricted pushrods with small oiling holes to keep as much oil from going upstairs with slow drain back. Make sure your pushrods are the correct length and you would probably only want to do that with roller rockers as well.
Last edited by Battenrunner; Jun 21, 2023 at 11:41 AM.
Was this a stock rebuild or a performance parts build?
What was your oil pressure when hot and with what weight of oil?
My recommendation:
1. Take your block to the best machine shop you can find, same for the crank. Don’t worry about hurting feelings, it is your engine and your time and money.
2. Have the shop mic the crank and check it for alignment (see if it rides the V blocks without warp along the journals or the nose), have it checked for stroke and runout on the main journals and the rod journals to determine if it is radially true or non-concentric like an egg. Let the shop measure everything, hopefully they are using a properly set (on a fixture)Sunnen bore mic for the main housings and main bearings. Do not use your own measurements to tell the machinist your numbers.
3. Determine if the shop can turn it to correct the current condition of being too tight while still running a .010 under bearing, if not, move up to the .020
4. Purchase new main bearings in correct under size and take to the shop to have them torqued into the saddles.
I like the speed-pro 108M bearings with 1/2 groove
5. Have the crank ground to give you .003 clearance on the mains and .0025 on the rods and have enough side clearance on the rods to let the trapped oil out.
Have it checked for thrust clearance and make sure you have enough to not wipe the thrust bearing flange out, especially now going to a manual trans with the load that adds to the crank thrust
6. For improved oiling to the mains, you can run restricted pushrods with small oiling holes to keep as much oil from going upstairs with slow drain back. Make sure your pushrods are the correct length and you would probably only want to do that with roller rockers as well.
Thank you very much for the detailed information. This was a minor proformance build. New pistons, mild cam, aluminum heads with roller rockers, Edelbrock intake. Nothing to crazy.
I tore the block down since it is apparent that I am going to have to take it some where to get looked at. Holy crap was i shocked at the condition of the top of the pistons, cylinders and the bottom of the heads!
My plan will be to find a machine shop to checkoit the above as you have pointed out and go from there.
Thanks again.
With an 80cc chamber, that puts you around 13:1 compression with a 4.155 bore, .010 deck clearance, and a .043 thick Fel Pro head gasket…. +/-
Was it rattling from detonation like crazy?
what do the rod bearings look like?
You fudged a number there. Using your assumptions its a 9.89:1 compression ratio. If I had to guess I'd say you subtracted the piston dish instead of adding it.
You fudged a number there. Using your assumptions its a 9.89:1 compression ratio. If I had to guess I'd say you subtracted the piston dish instead of adding it.
Argh!
you are right, I put a - in front of it, but it didn’t insert it in the calc
looks like 9.89:1 to me also now
I was getting all excited
Last edited by Battenrunner; Jun 21, 2023 at 06:35 PM.
UPDATE:
I found a top notch local machine shop to check out the crank/bearings. They confirmed that the clearance was at the very low end of the range. They confirmed that the crank is straight and usable. They are going to machine the crank so that it has .003 clearance on the mains and .0025 on the rods. They are going to bevel the oil holes, right now the edges are sharp. Once done it will be polished and then balanced. Thanks to all for the guidance.
Since I am rebuilding the engine I was hoping to get your thoughts on my current cam and see if it should be changed out to better match the engine, car and most importantly how I intend to use it. This car has and always will be a street car for me. I have no intentions of taking it to the track. I use the car for cruising around and I like getting on it from time to time. The engine was/is built with the intent of mild performance. It has Mondello aluminum 77cc heads with roller rockers, Edelbrok performer intake, Quick Fuel 780 carb, and headers, I am currently installing a TKX 5 speed. I have installed a set of 3.55 gears in the rear and I currently have P245/60R15. The current cam is a Mondello hydraulic JM20/22 Extreme.
I have not had any issues with this and it sounds ok. I was hoping for something with a bit more of a lope sound but I don't want to sacrifice performance for sound. I'd love to get your feedback on this, thanks!
Last edited by DLaz70OLDS98; Jul 6, 2023 at 06:09 PM.
I wouldn’t change it. If you want more idle lope and lower vacuum that goes along with it, recurve the distributor for less initial advance and connect vacuum advance to ported vacuum. That should corrupt the idle manners somewhat.
I am willing to put up with a lot more cam than a lot of Olds guys are…
So many are worried if their engine doesn’t pull 15 inches of vacuum burbling along at 700rpm for an idle.
If this was mine, I would go with a cam in the mid-230’s for intake duration and the mid to low 240’s for exhaust duration at .050.
If you can get a good cam in the .530-.550 lift range with these duration numbers, and have it cut on a 108 lobe separation angle, you can run a moderate valve spring that will still last a long time on a street car.
You could use a vacuum reservoir canister to help with the brakes, or worst case, just get an electric vacuum pump to run your brake system.
I went to a manual master cylinder to eliminate the booster being in the way, and knowing the cam would be marginally too big to run them.
Our cam is still a good bit larger than what I am recommending to you, by the way, but our car was going to be a street/strip build.
Another option, if you don’t mind checking lash periodically, is to move to a USA made solid flat tappet cam and lifters when you move up in size.
A big recommendation I can make if staying with a new hydraulic flat tappet is that you get quality American made lifters and cam core. You don’t want to do all the correct things with this good engine to have a cheap quality iron cam or junk lifter fail and ruin everything.
I am willing to put up with a lot more cam than a lot of Olds guys are…
So many are worried if their engine doesn’t pull 15 inches of vacuum burbling along at 700rpm for an idle.
If this was mine, I would go with a cam in the mid-230’s for intake duration and the mid to low 240’s for exhaust duration at .050.
If you can get a good cam in the .530-.550 lift range with these duration numbers, and have it cut on a 108 lobe separation angle, you can run a moderate valve spring that will still last a long time on a street car.
You could use a vacuum reservoir canister to help with the brakes, or worst case, just get an electric vacuum pump to run your brake system.
I went to a manual master cylinder to eliminate the booster being in the way, and knowing the cam would be marginally too big to run them.
Our cam is still a good bit larger than what I am recommending to you, by the way, but our car was going to be a street/strip build.
Another option, if you don’t mind checking lash periodically, is to move to a USA made solid flat tappet cam and lifters when you move up in size.
A big recommendation I can make if staying with a new hydraulic flat tappet is that you get quality American made lifters and cam core. You don’t want to do all the correct things with this good engine to have a cheap quality iron cam or junk lifter fail and ruin everything.
in interested in learning about how to run a “moderate” valve spring with an aggressive lobe?
So I have been trying to educate myself on selecting a cam, good lord did I go down a rabbit hole! Based on what I read about valve events and using the Summit camshaft calculator I came across 2 possible options that may fit my needs. I was hoping to get some feedback/thoughts if I am heading down the right path or if I am completely out in left field.
Option 1: Howard Cams 4/7 Swap 514825-10
Option 2: COMP Cams Xtreme Energy Retrofit Camshafts 42-423-11
I am surprised it is tight considering the 1-4 journal sizes are actually at the minimum of the spec. Not sure what the fix is going to be. Getting a crank guy to grind just .001-.002 off the mains is tough. Most of them dont want to do it. Mine will but he grumbles about it 
Based on what I read about valve events and using the Summit camshaft calculator I came across 2 possible options that may fit my needs. I was hoping to get some feedback/thoughts if I am heading down the right path or if I am completely out in left field. 
