hello everyone! i have a 1972 olds cutlass "s". We recently did a rebuild on the 350. After a few hundred miles we notice a knocking/rattling noise coming from the block. The person who helped me rebuild the engine suspects that the noise is coming from the cam gear where it meets the distributor gear. When we rebuilt the engine we noticed there is nothing to hold the cam in place besides the timing chain in front and dist. gear in back. We are thinking this allows the cam to move when its not under a load which is how its acting right now. Does anybody have experience with this problem or know a part i can buy to hold the cam in place? I take it all olds block are like this?  

i am also thinking im going to get a double roller timing chain which will hopefully stay tighter than the stock replacement timing set. Also we used a high volume oil pump with all new bearings. The engine just doesnt seem to hold oil pressure when it gets warmed up and idles. Anybody else have similar experiences with the olds 350?  

Another thing i have noticed is the knocking/rattle noise doesnt start until the motor is warmed up. It doesnt make any noise unless its in park and from 1000 rpm and up once it levels off at a constant rpm the noise starts. It rarley makes noise when its driven unless it is coasting and given a little gas. Under a load there is no noise.  

To what extent did you rebuild the engine?  Did you re-use the valve train, or any other critical moving parts? Not trying to be a SMT AAA, but just want to eliminate any obvious things. I've done a few of these and know what can cause stuff like what you are describing.

Thanks,  Bowser    

Hi man! well when we rebuilt the engine we used all of the moving parts that were in the engine originally except we got a new cam, a stock replacement timing set, all new bearings, a new high volume oil pump, rings, lifters, an edelbrock performer intake and carb. We did reuse the stock valvetrain, pistons, distributor, crankshaft, rods. Im at college now and will be takin the 350 apart agin in early may when i get home. As I said I have heard it could be the cam floating not sure though im just trying to get ideas before i start. What are you thinking??  

New cam and lifters - should be ok there. Agree with your assumption that a Cloys True Roller set would be in order. I re-use the oil slinger even though most references say it's not necessary.

On your valve train, I assume it is the pedistal double bolt H type. That's pretty standard and what is on my son's '72 Cutlass. When re-using them it is very important not to swap pedistals and rockers. Once they are worn in a certian way, if you put them with unlike pieces they will start making noise almost immediately. I guess it's that the unlike wear patterns cause the valve train to loosen up more and differently than it normally would. You may have to go to a full new set. You can get standard ones on Ebay as new old stock and it won't set you back much.

If you used your old pistons, or went with cast replacements without an over bore, then that could be a significant problem. The first 330 Olds I ever went through, the pistons and bores looked pretty good, so I did a re-ring only. It was on that engine that I found out about piston skirt slap and mixing up valve train components. I was able to take care of the valve train noise, but no amount of work would take care of the noise coming from the block. Years later I learned that it probably would have been fine if I had gone with forged pistons.

The oil pressure problems I am learning about as we speak. You slapped a high volume oil pump on there which I would normally consider mandatory. However, a guy on my Vanpool used to be an Oldsmobile man and he told me that by putting that type of pump on an Olds engine, it can create some problems. First off, Oldsmobile in their desire to have a quiet valve train routed extra oil up to the top of the engine leaving the pan somewhat lacking. With a high volume oil pump this is made worse by pumping even MORE oil up top which can leave the pan short.  This could be causing your oil pressure drop. You can buy oil flow restrictors that will even up the amount of oil flow that is going to the valve train and the bearings. I am about to learn how to use and install them as most resources I have read seem to think they are a must for a performance build.  I did not put them in my 330 Small Block that is in my '67 Cutlass, but I have enough into that engine that I will yank it out and put restrictors in if I start getting thready oil pressure. Along with the restrictors, there are some improvments that can be made to return oil to the pan faster, and there are pans made to fit street cars that hold 1-2 extra quarts of oil. They aren't cheap, but less expensive than redoing a fresh build gone bad.

If I can think of anything else, I will send it on to you.  Good Luck,

Bowser    

i've build several olds engines and never had a problem with the cam walking. that no oil pressure doesn't sound good and were the cam bearings changed too. it sounds like the knock is in the bottom end to me. and i agree about the oil pump deal. i suggest that you contact Mondello Performance and get the olds technical manual for $26 joe's been doing olds for over 40 years. i learned alot of tricks from the book and build some strong engines with never a problem.  

We did use new cam bearings with the new cam. Also we did only re-ring the pistons and that may very well be where the noise is coming from. We did keep all of the valvetrain components together. The the noise sounds like it is just coming from inside the block. It has a little bit of that light clicking from the lifters, but we figured thats not a big deal. The deep knock/ rattle is what were looking to fix. I guess ill be able to let you guys know what happens in may. I wont get home from college till then and thats when we are gonna take it apart to see what we got. About the oil problem, it seems like its ok while its driving around. Once it idles and is warm the oil light will come on. The oil pressure stays up when its run hard too.