So a buddy and I bought this engine rebuilt, with receipt of all parts installed, and built up the top end. Its an olds "468" making around 510 ftlbs of torque, with a nice big 268 comp cam. ANYWAYS, some issues were trying to resolve, and cant find any info on the net about it. Problem1) Low oil pressure at idle. Measured with two brand new gauges (the second ones are Sunpro). Both gauges show almost ZERO pressure at idle. (the first reading on the gauge is 10psi, and it hovers just below that reading). Its obviously not zero, because the engine sounds smooth. The idiot light has not come on (but works), and it hasnt blown up yet. Past idle though, the oil pressure is normal, usually around 40psi when cruising. The pump in it now, shows to be a "M22F" on the receipt and says "high volume pump". Spoke to D i c k Miller, and he recommended putting in a "0.25in spacer to increase pressure at idle. I have no idea what that means. Why is the pressure low? What pump should we replace it with? and what is this mod DM is referring to? Also worth noting, we are in the process of trying to remove the oil pan (in car, hopefully its possible) to be able to see what were dealing with, updates to come shortly. Not easy to do with an SFI scattershield, long tube headers, and the wonderful Z-bar with the 4sp. Problem2) Longtube headers and starter. Currently my buddy cant use this car to go too many places without a 15min cooldown time after each time the car is shut off, because the starter craps out. Either a boost, or waiting for the car to cool off fixes the problem. (the starter is brand new). He is thinking about replacing it with a mini high torque starter, but cant find any reviews on them. What would you recommend? Or what have you seen work well? He is looking at a Summit starter. Also debating having it rebuilt by a guy he found in town who specializes in starters and alternators and seems to have experience with olds 455s and their starting issues. He said hed rebuild it in the same housing but to a heavy duty grade, and it would basically be a diesel starter. What would you do? both for the starter and the oiling issue? Thanks in advance for any help you can divulge.
Problem#1: The "spacers" that D I C K is referring to are not spacers per-se. They are oil restrictors that go in the block side main bearing oiling holes. AKA - engine out, remove crank, put orificed down restrictors in block. I've always just put the cam bearings in with the holes a little off to achieve the same result - - IE - keep the oil down low, and don't push it all the way to the valvetrain. The valvetrain will be fine with restricted oiling. Unfortunately, neither one of those options can be done in the car, the engine should come out. Problem #2: Put on exhaust manifolds ...... :TU:
Olds 455 engines have a set of unique galley plugs in the front and rear. The usual suspect is the one in the rear that lubes the distributor. My guess is that the plug was omitted during the rebuild. The other issue could be the oil pump pick up. If it is not mounted properly, or the pick up screen came off, same result. I would pull the engine.
My buddy runs olds and from what I remember, you need to get a Mondello pump. I will ask him just to be sure of the name Mondello. But I remember there's a big issue with these olds oil pumps. He had the same issue if I recall correctly. Stand by, i'll talk to him today at some point.
The original starters had a heat shield . Most have been trashed as they are a bitch to put in place. A Mini starter will cure the problem but a good one is pricey.
What PaulGS is saying is in addition to what I said. The other lube mod to an Olds is to weld up the small hole in the galley plug for the timing gear. It doesn't need it. Conversely, you drill a .025"ish hole in the galley plug that is right in front of the distributor shaft for distributor oiling. PS - Don't be fooled by a "Mondello" pump. A Melling pump is more than adequate if the oiling system is properly configured.
There are a lot of things that people do to Olds engines that they don't really need unless you're running BIG hp in a race motor. Most of these traced back to the Mondello performance book he put out a long time ago. Oil restrictors are one of those. Most of the big time Olds engine builders (I'm not one by any means:laugh: :laugh: ) today have determined that it's block and crank flex that cause the catastrophic failures in race engines. At the time this all started, Olds big blocks had shorter strokes than today. The early 400 and 425's (64-67) revved a lot higher than the newer 400(68-69) and 455's (68-76). We removed all the restrictors in my 400 in the recent total rebuild. It had the Mondello pound in aluminum oves in the oil galleys, and restricted pushrods. Don't know about redrilled and repositioned cam bearings, but all were totally worn through on the bottom side after only 30 minutes of low load running, never revved or driven. 2 lifters also were dry, and made a racket as well as contributing to the rough running. Melling oil pumps are very good, the one you have is not a high volume pump, the part number for that has an H added to it. (M22FH). That's plenty sufficient and may be what you need to keep from running your sump dry on all out 1/4 mile blasts. As someone mentioned above, you may have a pickup that's not matched to your oil pan. The Mellings use a bolt on pickup and come in standard height as well as 1 inch more drop(Toro pan), and 2 inch drop (Moroso, others.) Not sure why Dick Miller would give you that advice, my personal feeling is he has the perfect first name. Joe Mondel;lo is OK, but his old company is not. He sold it to Lynn Gellfringer (sp?) and I'd avoid them. Very porr business practices and customer service. Joe moved his school and machine shops to Tennessee, and is back to the old Joe we remember from long ago. Pull the engine.....you'll thank yourself in the morning.
What Dick Miller was referring to with the "spacer" was the somewhat common operation of SHIMMING THE OIL PUMP SPRING to achieve higher pressure....if you have zero oil pressure at idle then you likely have other, bigger problems as others have mentioned above and shimming the oil pump spring isn't going to solve your problem. Oil restrictors are a different "operation" from the "spacer" he was referring to and wouldn't solve your problem anyway...besides, the consensus seems to be that oil restrictors are a "take or leave it" proposition on the Olds motors running a hydraulic cam...as many people are going fast WITHOUT THEM (and not blowing up motors) as there are using them. Forget Mondello (the place in California)....they DON'T MAKE PUMPS ...they buy and resell Melling, etc. just like all the other vendors. My strong advice would be to avoid that vendor as has been mentioned. I would not plug or otherwise modify the hole for the timing chain "oiler" plug. The motor should have also have a screw in plug on the back of the block with a small hole in it for distributor oiling. The first thing that comes to mind is you said "we bought this engine rebuilt"....uggggghhh!!! Here are a couple pics of the plugs that are used ON THE FRONT OF THE BLOCK --On the L is the larger thread size plug with no hole. On the R is the smaller thread size plug with the small hole for distributor and timing chain oiling. Both of these plugs are used on the motor...the thread size determines which hole they are installed in (NOTE: with the motor upright on an engine stand and with you facing the front of the motor---the smaller threaded plug WITH THE HOLE IN IT will screw into the hole to the L of the cam, the larger plug (no hole) will screw in to the R of the cam). You can't mis-install these as the thread sizes are different...hard to screw up. They are behind the timing chain/cam gear.
Agreed...That rear plug directs a fine stream of oil directly onto a Core plug in the rear of the block that covers the access to install that plug. Big mess and a lot of work if it comes out. Mine did twice after a rebuild. Now has a 3/4 inch pipe plug in there... It is a unique size and doesn't come in the aftermarket plug kits. Both the timing chain and the cam gear on the distributor are the second most critical area for wear with the cam to lifters being the first. They need oil. Also anyone running steel rockers with spherical pivots (non roller or shaft mount) need oil for cooling as well as lubrication. They don't last long if tyou cut off the oil flow up the pushrods. All of us Pure Stock Olds guys use them, right? :laugh: :laugh: :laugh: I do.
I had a poorly welded Milodon pick up screen on my 455. The welds let go, and the pick up screen fell off the tube. The suction from the tube pulled the pick up to the tube opening, reducing my oil pressure to about "0".....uzzled: The resulting damge was: cam, lifters, bearings, etc. Required a full tear down and rebuild, cost me a lot. The Milodon folks were real a-holes when I contacted them....had to get a lawyer.
Since your idle oil pressure is about 7 - 10 psi, and your cruising oil pressure is also only a little lower than normal for a street engine, it is entirely possible that the entire "problem" is simply due to the builder having built the engine with larger bearing clearances -- which is something typically done for race engines, or any engine which may see high-rpm use. So there may be nothing wrong at all. It's the volume of oil that flows through a bearing surface that's important, not the pressure of the system. Of course, the other possiblility is that the builder did screw up (or something has broke/worn since the build). The only way to know for sure is to take it apart and have it inspected by someone qualified and trustworthy. I'd do a little grapevine research on the original builder first before tearing into it. As for your starting problems, make sure you check the strength, size, and condition of your battery and both positive and negative cables before you go replacing or rebuilding your starter. Headers are not necessarily a death sentence for starters. Most starting problems are due to a weak link in the electrical chain.
The engine was rebuilt, and never fired. We did the valve train, and top end and broke it in. The cam bearings looked brand new, and the cylinder bores still had crosshatching in them. It was a fairly "mild" build, but maybe the did use large clearances. I have no idea. The oil pressure is not zero, because the idiot light would come on @ 2psi or less. The first reading on the gauge is 10psi. However, on an analog gauge, the smaller the readout, the less accurate it is. So it doesnt really mean anything. At idle the needles dips just below the 10psi. The car runs very smooth and has a bit of mileage on it now, even a couple drag strip passes, but just the pressure dipping that low at idle is worrying. Batteries have been replaced twice, new terminals, and tested to make sure theres no drain in the vehicle wiring. The starter is the issue.
Makes sense. Big clearances = lower oil pressure. And if you have some pressure at idle then shimming the oil pump may do the trick. Sounds like you may need to get in there and "take a look" anyway so if nothing else is wrong then shimming the oil pump spring will give you some more pressure. Other than that, with no other problems found, you would have to re-machine parts to get tighter clearances and more pressure. Switching to a HV pump, while retaining the stock 4 quart (+ 1 in the filter) oil pan isn't a good idea either (as DaveH mentioned) because you risk running the pan dry at higher rpm's....then you will have some problems! It would be nice to know what clearances they used on the mains and rods. Get a good oil pressure guage that at least has a "0" reading on it....a quick look over the guage selection at SummitRacing shows a large number of AutoMeter, etc brand that read down to "0"....still, they don't appear to have a "pound-by-pound" reading below 10 psi but you can do better than the Sunpro for sure.
This engine has had some "oil mods" done to it, according to the seller. And theres restricted pushrod in there to remedy the pan running dry problems.
Again, with the stock pan and a stock-type oil pump like the Melling pump it looks like you have, running the pan dry shouldn't be a problem..."restrictors" or not. If you are satisfied that everything else is OK, then you should look into shimming the oil pump spring...BUT...I cannot guarantee you it will raise your oil pressure AT IDLE since it's a RELIEF SPRING. In other words, I believe shimming it only raises the point (psi) at which the relief operates. Someone can correct me if I'm wrong but to me, that means doing this may only raise your oil pressure at higher rpms (when the "relief" part of this equation comes into play---higher rpm = higher psi = relief spring "as is" is set to "relieve" at 40 psi and shimming it might raise that number to 50-60 psi before the relief spring comes into play-but that is only "at rpm" not at idle where the relief spring is "inactive"). That's as far as I go on this one. You are now far into "engine builder" territory.
Patton, you are correct that shimming the relief spring will only raise the MAX oil pressure, not raise oil pressure all the time. Based on online170's description, shimming the spring will not raise the pressure at cruise either. The only time it would have any effect is at cold start-up, when the oil is thick. The factory relief spring is set for 60 psi, so it shouldn't even be opening if he's seeing 40 psi. Of course, that does raise another possibility: the pressure relief valve might be stuck partially open. Yet another possibility is that the base of the oil pump may not be sealing against the rear main cap. I have heard that the housing of one of the aftermarket pumps (maybe Melling) interferes with a main bolt head (or nut, if you're using studs). It's real easy to miss, because you tighten the pump down and think it's seated, but there's actually a gap, allowing oil to squirt out.
Brian, those three descriptions are along the same lines were thinking. Will have to tear into it and see what we find. Maybe next weekend.
Good call Brian....I remember some old threads on ROP that seemed to revolve around that rear main cap improperly installed and/or the oil pump install that you mention. If you are going to be pulling any bearing caps then you might as well check some clearances while you are at it....maybe this thing was set up "ultra loose" on purpose. One engine machinist recently told me "loose makes HP". At some point, however, you can overdo it. Are you going to pull the motor and put it on a stand or leave it in the car??
dont know yet.... Its not easy to pull the motor....... and i definately dont want to take the trans off.
