Bgdaddy455

Good morning,
i finally dropped of the block, crank and heads to the machine shop and in the process of buying some new parts. After having a rod knock i want to do everything i can to reduce this in the future. There are so many ideas and depending on who you ask diferent answers. I dont know if its because some of the posts i have seen are from 10 or 15 years ago or not? This is my first BBO rebuild so im green as hell bit going for it anyway. Here is what i have read so please help me clear this up. It will be a 10:25-1 compression motor with a N crank, eagle rods and lighter forged pistons (havent figured out which ones) it will be driving locally most and maybe a.few trips to the strip.
i have heard to do the restrictors in the mains and some dont thinks it works?
I have heard to run restricted push rods but may here clatter and not have enough oil on the top end at high revs?
I have heard to open up the galley for the oil pump?
i have heard cleaning up the lifter galley slag can help?
I have heard about even painting the the inside of the block under the intake with a glycol type paint (never heard of thos paint)?
I have heard using a 7qt oil pan with a high volume pump (not high pressure)?
I have heard about tear dropping the drain back hole behind the timing chain cover?
I have also heard of running an external hose from each head back to the pan?
should they all be done or is there a combination of things that will actually work? I just want to do my part to protect the bottom end.
When i got the rod knock i was on the highway pulling about 3000 rpms for a while tjen passed some someone and got to about 5500 rpms, started to slow down and heard the knock and immedietly pulled off and called a tow truck. The number 8 journal was destroyed. Motor had about 30,000 miles on it.
thanks for any help

matt69olds

First, find a machine shop familiar with Oldsmobile. Or find a machinist that won’t argue when you request things to be clearances with what Olds engines like. The larger bearing clearances will need a high volume pump.

If you study the oiling system, you will notice the cam bearing restrictions will do nothing. The cam bearings are the end of the line for the oiling system.

Oil restricted pushrods area ok with a full roller rocker, I wouldn’t want to restrict oil on a ball pivot style rocker.

A oil pan with extra capacity never hurts. Anything you can do to keep the oil away from the rotating crank is a good idea. Just because the pan has a 7 quart capacity, doesn’t mean you have to run 7 quarts. If you think about it, running a 7 quart pan with 6 quarts will result in 2 additional quarts of oil over the stock pan, and keep the oil away from spinning parts.

Tear dropping the timing cover drain isn’t a bad idea, but probably unneeded. There are plenty of other places for the oil to return to the pan.

I have heard of the drain holes in the heads helping when the engine is in a boat. Those engines run at higher RPM for far longer periods of time than you could in a car.

While the theory of painting the lifter valley is sound, I’d rather not run the risk of paint eventually flaking off. I suppose polishing the lifter valley would accomplish the same thing, just be very time consuming for questionable benefit.

Bgdaddy455

Thanks for the reply. The shop im using doesnt do alot of olds but has done them and after talking with him he did point out some of the issues in this post. He seems willing to do whatever i want so i dont think thats a problem. I was told by a guy who owns a olds speed shop near me that i should try for .025 clearance on the mains. Does that sound right?

Koda

The best thing you can do is be realistic about what this car will see. A race engine needs more than a street engine with an occasional drag race, which needs more than a grocery getter. Very rarely does any mechanical change come without some sort of compromise elsewhere. Give it just what it needs and like 20% more.

Sugar Bear

A main bearing clearance of 0.0025 is what we aimed for years ago and it worked. That isn't .025. There are other critical clearances such as rod bearing clearance again we aimed for 0.0025. There is also connecting rod side clearance and crankshaft endplay.

Hopefully some of our members that are currently building engines will chime in as materials, parts and time may change the recommended specs.

Good luck!!!

Bgdaddy455

Thanks. Sorry i meant .0025. So both mains and rods at .0025 would be the best? Do you have the side clearance spec? Also what is done to modify the side clearance if need be? If it sounds like i dont know what i am doing its because i dont lol. But everyone hase to have a first time. Its kind of embarrassing really when i ask a question and see a response that should have easy to figure out so for that im sorry. Im not knocking anyones response just trying to be truthfull and upfront. I appreciate every answer.

Sugar Bear

I don't recall the other specs and would rather rely on some of the current engine builders for their current info/data. The rod side clearance can be increased if needed by machining material off the side of the crankshaft end connecting rod and bearing cap. If you are staying close to stock there is probably no need to modify the current clearance.

Yes 0.0025 rods and mains was our target, but that was a long time ago, modern techniques may have changed that slightly.

Bgdaddy455

Im going with the eagle H rods. Im assuming they have stock dimensions

OLDSter Ralph

A. I am not a fan of restricting oil.
B. Cleaning up the "casting flash" in the lifter valley can aid the oil drain back a little. Do it, if you like, but don't spend a lot of time on it.
C. Painting the inside of an engine block has been done before. Surface prep for "Glyptal" (product name) has to be meticulous. This product (Glyptal) is used in industrial lubrication applications and electric motors, and is not subjected to temperature extremes of a car engine. Removing casting flash would help. Polishing the the lifter valley would work the same as Glyptal.
D. A light spot facing and a slight champfer or radius around oil return holes won't hurt oil drain back. This would be more beneficial on the cylinder head oil return holes.
.......Just my two cents worth

Sugar Bear

I don't know about Eagle's but no matter what rod is used, measure the clearance. It is easy and can be done with a feeler gauge. Always measuring is the best practice.

Good luck!!!
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Bgdaddy455

thanks for the response. I think i would rather polish the valley than do any kind of paint.

Bgdaddy455

agreed. Thanks again

70W-32

Where is this shop at?

Who you using for the build, will he do the break-in for you?

Bgdaddy455

this shop is in Fraser Mi. I am doing the build. They are doing all the machining, balancing, hot tank, magna flux, on the block and heads etc. I was going to have them do the short block but changed my mind. I have all the tools to double check all of the machining and after reading many posts on several sites (mostly this one) many recommend double checking any work performed so why pay them for assembly if im pulling everything apart.

70W-32

Im specifically looking for the Olds speed shop you mentioned

Bgdaddy455

his shop is near Flint Mi. I made a typo on the clearance he mentioned. He said .0025 which others have agreed with. I just asked becaus i thought i saw on another post that one of the mains should have more clearence.

Sugar Bear

Assembling the short block yourself allows you to measure as you stated and it allows as much time as you choose to take for cleaning oil passages etc. Invest in a set of engine cleaning brushes if you haven't.

Also consider removing all threaded oil galley plugs, tag them, note which locations have plugs with drilled orifices. After cleaning the block, reinstall the plugs in the correct locations yourself.

Good luck!!!