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Jul 21st, 2025 | | | | Joined: Jun 2007 Posts: 100 Shop Shark | | Shop Shark Joined: Jun 2007 Posts: 100 | Getting ready to fire up the 49 with a later model 235. I read the first 30 pages of topic titles and didn't see any that dealt with modern oils in classic engines. On a Lincoln Continental site that I also read there is a lot of discussion about what oils and additives to use. Anything in particular I should use or avoid? Should I drain the old oil first and refill or try to start and run for a while before dumping it to change? The last tags were 98 and maybe driven a little later but not very much.
My new 1949 Chevy One Ton Dump Truck. Still have it but parked, needs a new motor.
1953 2 ton parts truck Long Gone
1957 GMC LCF On 75 Cadillac Eldorado Frame
Updated Feb 2021
| | | | | Joined: Dec 2004 Posts: 1,897 Shop Shark | | Shop Shark Joined: Dec 2004 Posts: 1,897 | Make sure the oil has plenty of zinc.
Has your engine been torn down, cleaned and reaasembled? If so a modern detergent oil with zinc won't hurt it. If Not, a straight weight oil with zinc additives will likely need to be used. Most oils that are sold for racing applications have elevated levels of zddp or zink. Unfortunately most racing oils sell between $4 and $12 a quart. | | | | | Joined: Oct 2006 Posts: 1,847 'Bolter | | 'Bolter Joined: Oct 2006 Posts: 1,847 | put clean oil to start, it isn't nearly as expensive as rebuilding one of these engines. As the other fella mentioned, study up on the government oversight regarding zinc levels, now I know why all the car companies are going to roller cams... its not for high performance, it is for poor government performance. Anyway most all of the major cam companies have info on zinc levels needed for break-in, and for running under various conditions. Doing a bit of searching on the interweb will give you reams of information on this. | | | | | Joined: Jan 2011 Posts: 13 New Guy | | New Guy Joined: Jan 2011 Posts: 13 | My past experiance over the last 25 years would offer this opinion;
I have found no problems in using modern "straight" weight oils in the engines I have been operating, be it GM 4s, 6s, Ford 4s, 6s, and V-8s. I try to change oil on a regular basis and use 30 weight. The vehicles I operate are not driven very hard and as I approach my 73rd birthday, they tend to be driven only in fair weather. | | | | | Joined: Apr 2005 Posts: 1,971 'Bolter | | 'Bolter Joined: Apr 2005 Posts: 1,971 | Use Rotella.
Many Corvette enthusiasts use it and it still has zinc in it. | | | | | Joined: Oct 2005 Posts: 1,317 Shop Shark | | Shop Shark Joined: Oct 2005 Posts: 1,317 | Modern oils have had much of the zinc/phosphorus removed as it was adversely effecting modern catalytic convertors. This can cause serious issues in a rebuilt engine that is running a flat tappet cam, especially during the initial cam break-in and if there are heavier-than-stock valve spring pressures.
You didn't mention whether your later model engine had been rebuilt or it just needed to be refired. My experience has shown that if you are cranking a freshly rebuilt engine with a flat tappet cam, it is wise to use an oil with 1800 ppm additional zinc. Granted, these oils are a bit more expensive initially but are much cheaper than having to replace a cam with a flattened lobe. I normally purchase this oil from Summit Racing in either SAE 30,10w40 or 20w50 for $5.95 a quart. Contrary to popular belief the Rotella Diesel oil, which at one time had a higher zinc/phosphorus content, no longer has the higher content and I had issues with lifter noise.
If you're just going to fire up a used engine with a stock cam that has been broken in, I'd pull the valve cover and check out the rockers for sludge. If the rockers are clean and the oil on the dipstick isn't too nasty I'd pull the sparkplugs, spin the engine with the starter to build up a little oil pressure, put the plugs back in and crank up the engine and warm it up until I had oil to the rockers. Then I'd drain and replenish the oil with either off-the-shelf SAE 30 HD or 10w30 while if some light sludge exists I'd use 10w30 and plan on initially changing it and the filter at 1000 miles.
With the price of oil at nearly $3.00/qt locally, and with the reduced zinc/phosphorus contents, springing an additional $20.00 for an oil change is cheap compared to replacing a camshaft and lifters and cleaning out a bunch of metal from the sump. As for additives; Lucas sells a "break-in oil" suppliment at about $14.00/bottle and GM sells EOS (which used to be $7.00) for $22.00 a pint so the 1800ppm oil at $5.95 is pretty cheap insurance against wiping out a cam and doing additional damage to your engine. Hope this helps answer your question.
Dave
| | | | | Joined: Jun 2007 Posts: 100 Shop Shark | | Shop Shark Joined: Jun 2007 Posts: 100 | The 235 was installed in the 60's. Nothing much after that according to the records I have. Was parked in the shop in 72 and stayed there till 97 or 98. Driven around a little for a couple of years then sat till now. Oil is probably from 98.
My new 1949 Chevy One Ton Dump Truck. Still have it but parked, needs a new motor.
1953 2 ton parts truck Long Gone
1957 GMC LCF On 75 Cadillac Eldorado Frame
Updated Feb 2021
| | | | | Joined: Feb 2000 Posts: 4,886 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 4,886 | Dave explains it really well, the only think I can add is about valve springs. Heavy valve springs and radical flat tappet cams are what get killed with low zinc levels. If you have a stock cam with stock valve springs, you won't have any problem. A 235 spring might have 60 or 70 lbs at rest and 120 or so full open, a good race spring starts at 120 to 140 installed and go to 290 to 320 lbs open. So you can see where 320 lbs of spring pressure is way different then your 110 lb or less springs. And once a cam has been polished to the lifter, is not nearly as critical to have as much zinc as a new cam needs.
On my 250, I can push the valves open just a bit with my fingers, the springs are just not that strong, so I run 10-30 oil with no additives. Dad and I have raced cars for years and have built many engines. We lost one cam a few years back before the word was out about reduced zinc. And like everyone says, it wipes the lobes right off the cam, and it didn't take but just a few miles once the fellow heard the rocker arm clatter a few times.
Joe | | | | | Joined: Apr 2005 Posts: 1,971 'Bolter | | 'Bolter Joined: Apr 2005 Posts: 1,971 | This was posted on the hotrodders forum by a member who emailed Shell Rotella:
I have heard that Rotella T CI-4 is being phased out, replaced by CJ-4. Is the ZDDP content being reduced? If so, by what percentage, or what will the PPM of ZDDP be with the new oil if its not a trade secret? The hotrod guys are dying to know, we've all been using Rotella due to flat tappet camshaft break in problems using the new oils without the ZDDP additives.
Here is his reply:
We still sell Rotella T 15w-40 CI-4 in 55 gallon drums, but not in smaller packages. It has approximately 1400 ppm zinc. You can buy this from a shell lubricants distributor.
Since Oct. 15,2006 all small packaging has been Rotella T with triple protection 15w-40 CJ-4 and it has approximately 1200 ppm zinc. This is 50% more zinc than current passenger car motor oils which contain approximately 800 ppm zinc. Passenger car motor oils had approximately 1200 ppm zinc prior to 2001. In 2001 the zinc was reduced to 1000 ppm and in 2005 reduced again to the current 800 ppm.
Thus, the new Rotella T with triple protection 15w-40 CJ-4 has the same zinc content that passenger car motor oils had in 2000 before the current problems with flat tappets began.
However, zinc compounds are not the only additives that can reduce wear. We were able to reduce wear approximately 50% with the new Rotella T with triple protection 15w-40 CJ-4 formulation. | | | | | Joined: Oct 2005 Posts: 1,317 Shop Shark | | Shop Shark Joined: Oct 2005 Posts: 1,317 | Joe hit the nail on the head...."once the cam has been polished to the lifter it is not as critical to have as much zinc as a new cam needs." It's that first 60 seconds where the zinc/phosphorus content plays a critical role in properly seating the cam-to-lifter surface. The surface of the lobe is hardened just "skin-deep" and the thought of reducing the life of the cam/lifter to save a few bucks just doesn't make sense to me.
On my 1960 235 engine with stock spring pressures I add 2 ounces of GM EOS to a full oil change after using the 1800 ppm oil for the initial run-in. I currently have 13K on the engine and my $9.00 oil analysis comes back A-okay!!! Pretty cheap insurance against catastrophic engine failure.
Dave | | | | | Joined: Jan 2011 Posts: 15 New Guy | | New Guy Joined: Jan 2011 Posts: 15 | Personally I would drain the old oil before I started it then warm it up or take a test run or whatever then drain again. Oil is cheap compared to bearings & changing them & I have seen engines that sit for years wipe out the bearings quickly. | | | | | Joined: Jul 2005 Posts: 640 Shop Shark | | Shop Shark Joined: Jul 2005 Posts: 640 | I don't buy all the concern with zinc and the like. I've been running 10W-30 in mine since 2008, and no trouble whatsoever. Today's oils are way better than the oils used back when that engine was made, and I can't see how it wouldn't be an improvement for the engine. Zinc, schmink. | | | | | Joined: Nov 2004 Posts: 121 Wrench Fetcher | | Wrench Fetcher Joined: Nov 2004 Posts: 121 | I use JD 15-40 in all of my older engines and all of the farm machinery.
I use the lighter weight oils only in the later model vehicles. I am actually using 5W-20 in my Neon. I would like to use it in my newer model v8 Chevrolet, but it is still under warranty and they recommend 5W-30. After the warranty is off, I think I will switch to the lighter oil.
| | | | | Joined: Jun 2010 Posts: 301 'Bolter | | 'Bolter Joined: Jun 2010 Posts: 301 | Tom R - I'm with you. My dad is a 82 yr old retired farmer and a life long mechanic. Owned these trucks when they were brand new. He is helping me restore my 49' 3600. I run 10W-30 and change out every 3000 miles. I do this on all of my vehicles. I have a 75' Hurst olds that I restored, my daughter is driving my old dodge pickup with 200K miles on it with the original motor and no re-work. Use a quality oil and change it routinely and it will run just fine. Jusy my 2 cents....
Last edited by bztguy; 02/23/2011 3:30 AM.
1949 Chevy 3600
1975 W-25 Hurst Olds
1970 GMC 1/2 ton Fleetside
2010 Chevy Silverado
| | | | | Joined: Nov 2006 Posts: 2,544 Shop Shark | | Shop Shark Joined: Nov 2006 Posts: 2,544 | I'd pull the plug and drain it. Then you know if you have anything extra laying in the pan besides oil, antifreeze will lay in the bottom of the own and not show if you pull the dipstick. Lots of things can get in a pan during a 20 year nap...even mice. | | | | | Joined: Jan 2011 Posts: 85 Wrench Fetcher | | Wrench Fetcher Joined: Jan 2011 Posts: 85 | I have been thinking about this for a while now. If zinc is important to engine with flat rappers ten why are there not more issues with car on the road. Not "modern" cars but roller rockers were not standard in a lot of cars. Yet they still function fine. I used regular 10w 30 in both my Camaro and mustang without issue and both are flat tappet engines.
52 Chevy 1/2 ton - work in progress 65 Mustang coupe - work not in progress  67 Mustang GT convertibile 67 Camaro RS/SS We are now even with fords and chevys. Now i need a mopar. Hahahahahahahahaha
| | | | | Joined: Jun 2008 Posts: 145 Wrench Fetcher | | Wrench Fetcher Joined: Jun 2008 Posts: 145 | I run a diesel 15-40 oil with gm eos , we can still get that here for $9.This truck (54 with original 235 rebuilt 20 years ago)only runs in warm weather. | | | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | Zleviticus, you've hit on it exactly. Most of what you see in the whole zinc additivve business is snake oil. They overexagerate the issues to make it look like there's an actual problem, when it really isn't. Now that's not to say there hasn't ben cam failure issues, but most of them fall under the following catagories; Incorrect assembly; Incorrectly matched or improper parts (race springs on a street cam, for example); Poor quality/defective parts; Improper break in procedure.
If you use a good quality motor oil, you'll be fine. Also, I would advise against using a Deisel grade oil, especially in an engine that's already been run on gas engine spec oil due to the hihger amount of detergent in Deisel spec. It'll clean everything out of the pan and crankase, potentially risking plugging up oil galleries, as well as clearing out any varnish buildup on the seals, making the leak.
Bill Burmeister
| | | | | Joined: Aug 2004 Posts: 1,067 Shop Shark | | Shop Shark Joined: Aug 2004 Posts: 1,067 | Longbox55, that isn't correct. There is absolutely no problem running diesel 15W40 in a gas engine. Too much detergents? Since when did that hurt anything? And the zinc phosphate issue, (ZDDP) is very well-documented. In fact, Hot Rod magazine did an elaborate write up on it. The zinc was cut out of oil because of pressure from the federal government. With the advent of modern roller cams, which is now on 100% of all new cars, and also because of increasing the life of factory catalytic converters, zinc was eliminated from the oil formulations. This is not snake oil. If you don't believe it, a very brief internet search will educate you on it. But do what you like. It's your truck and it's your choice. No one's twisting your arm one way or the other.
52 GMC 3/4 ton pickup
68 Big Block Vette
68 455 Firebird
| | | | | Joined: Jan 2011 Posts: 85 Wrench Fetcher | | Wrench Fetcher Joined: Jan 2011 Posts: 85 | From another Classic car forum. The basic principle of lubrication is to maintain an oil film between moving surfaces. As long as an oil film is present, wear is not possible. On a properly designed engine (there are exceptions!) fed with oil of appropriate viscosity, the oil film will only be absent under one of these two circumstances:
-during start up, before oil has had enough time to reach every moving part;
-under extreme pressure, when oil starts breaking up (which implies that the oil wasn’t appropriate to start with).
If these circumstances didn’t exist, anti wear additives wouldn’t be required. Whenever the oil film is broken, the moving surfaces rub against each other and heat up; ZDDP reacts to heat and sticks to the heated surfaces, building up a protective film. Until then, zinc stays in suspension. This film stays there until more contact occurs. “Anti wear” does not entirely prevent wear, it mostly prevents the contact surfaces from welding together and ripping little pieces away.
One of the key areas where metal to metal contact is likely to occur at start up is at the cam/follower interface. It is a high pressure contact, and far away from the oil pump on an overhead cam engine. Single overhead cams are actually worse than our DOHC Alfa engines, as the cam lobes have little puddles of oil to dip in.
API’s requirements for oil certification are based on performance, not chemistry (other than limiting zinc contents due to catalyst requirements). In the current SM standard for gasoline engine oils, sequence IV-A test addresses anti wear performance at the cam/follower interface. This test is run on a Nissan 2.4 SOHC engine (240SX); it replaced the V-E test based on the Ford 2.3 (Pinto) engine. The anti wear requirements of SM motor oils are actually more stringent than SM specs, which were more severe than SL. This is in spite of the reduction in zinc contents: SM oils use other anti-wear chemistries that work, and some have been around for quite a while - for example in locomotive lubricants.
Also worth mentioning: diesel engine oils such as Shell Rotella or Chevron Delo are not such a good idea on anything but a new engine. They have a much higher detergent contents than gasoline engine oils. Especially if your engine has been fed a regular diet of motor oil with a weak detergent (and I’m finding several evidences that Castrol GTX is such an oil) the diesel stuff will clean out a lot of sludge which may lead to a clogged filter. All this for nothing, as current CJ-4 diesel oils are also on a zinc reduction diet.
52 Chevy 1/2 ton - work in progress 65 Mustang coupe - work not in progress 67 Mustang GT convertibile 67 Camaro RS/SS We are now even with fords and chevys. Now i need a mopar. Hahahahahahahahaha
| | | | | Joined: Jan 2011 Posts: 85 Wrench Fetcher | | Wrench Fetcher Joined: Jan 2011 Posts: 85 | BTW the hotrod article (i found it online) says that new oils may not be good for .. drum roll please... "for older flat tappet-equiped vehicles, running non-stock, preformance cams, and valvetrains." Also that the issue is NOT just with the oil but with poorly made and heat treated cams and lifters. http://www.racingheadservice.com/Information/ArticleDetails.asp?ID=-1228096506
52 Chevy 1/2 ton - work in progress 65 Mustang coupe - work not in progress 67 Mustang GT convertibile 67 Camaro RS/SS We are now even with fords and chevys. Now i need a mopar. Hahahahahahahahaha
| | | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | I never said there was a problem with using deisel grade ina gas engine, only that using it in an unknown condition engine that has been run on conventional oil could be an issue, as you do not know how much sludge or other contaminants could be in it. Plus, with the higher detergents level, it can cause seal leaks by clearing out any varnish buildup in the seals.
I know all about the zinc reduction. I also know that the oil companies test their oil on (wait for it) FLAT TAPPET ENGINES for the cam wear tests. I've been running SM grade oil in my engines, all flat tappet, one '85, one '55, and one '48, with 0 problems at all. The '85 and '48 both have stock cams, the '55 has a Howard M4F. Proper break in and assembly is the key.
BTW, Valvoline does their cam wear tests with an engine running a flat tappet cam.
Bill Burmeister
| | | | | Joined: Dec 2001 Posts: 14,522 Moderator: Welcome Centre, Southern Bolters, Legion Hall | | Moderator: Welcome Centre, Southern Bolters, Legion Hall Joined: Dec 2001 Posts: 14,522 | ...longbox55 statement "Proper Break in and assembly is the key" says it all. If my memory is correct a lot of the ZDDP fight started when folks started up new engines without "proper break in" using oils that did not have sufficient levels of it. Cam builders and racing shops produced many articles on this.
IF you use the proper start up on a new engine then you can run engines on "most" any oil. ....(I didn't say ALL oils)
Dump a quart of GM E.O.S. in with your oil in a new engine, and after the PROPER BREAK IN you should be fine. BREAK-IN is the real critical part...especially for Cams/lifters.
OOOK, now I've had my .02. | | | | | Joined: Jan 2007 Posts: 83 Wrench Fetcher | | Wrench Fetcher Joined: Jan 2007 Posts: 83 | Ok, I will hide here in the corner and throw my $0.02! Rotella T on an engine that has been rebuilt or had the pan/filter pulled and cleaned. Non detergent motor oil for an engine(216, 235, 261 fresh out of long time retirement) that has had the old oil drained, new oil added then drained, then Non detergent oil added than run.
Jason | | | | | Joined: Feb 2000 Posts: 4,886 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 4,886 |
Camshaft makers like you to not add zinc, they can sell more cams that way!
Joe
| | | | | Joined: Jan 2011 Posts: 85 Wrench Fetcher | | Wrench Fetcher Joined: Jan 2011 Posts: 85 | Yeah that makes a lot of sense. Make cams that fail. I am sure that they really want to be known for cams that fail to increase their sales. I can see a bunch if people in line buying cams that have a history of failing. Think about your logic a little.
52 Chevy 1/2 ton - work in progress 65 Mustang coupe - work not in progress 67 Mustang GT convertibile 67 Camaro RS/SS We are now even with fords and chevys. Now i need a mopar. Hahahahahahahahaha
| | | | | Joined: Dec 2001 Posts: 14,522 Moderator: Welcome Centre, Southern Bolters, Legion Hall | | Moderator: Welcome Centre, Southern Bolters, Legion Hall Joined: Dec 2001 Posts: 14,522 | .... I thnk Joe was being a little...shall we say "sarcastic". I could see his smile from here. | | | | | Joined: Feb 2000 Posts: 4,886 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 4,886 | Nobody is out to sell you a bad cam, but if you don't follow the manufacturers advise given, thats just what you get. Its not made up stories or tails, its not instillation problems or break-in problems, is a oil lubrication problem. If some wish not to believe it, fine don't bother with it and save you money.
Its been said many times, not all engines require the same protection and most older ones do not. Hydraulic cams are not as susceptible as solid flat tappet cams, roller cams need nothing but good clean oil. The older stock flat tappet cams are so mild compared to whats out there now, they only require minimal zinc due to the lift and spring rates. Reground cams are considered as new and should be treated as such with maximum protection.
Any engine all ready running before 2000 should be just fine, they are all ready broke in. It does matter if it hasn't run for 20 years, if it has been broke in and run before the zinc removal in 2000 it will be fine as long as its a stock engine, optional factory high performance type engines don't apply here.
Any rebuild engine with mild to stock valve springs and stock cam should be fine with a name brand oil and a little protection, weather that be a little GM EOS, diesel oil, or a little zinc break in oil. Its the high lift cams and heavy valve springs that load the camshaft/lifter contact area, if yours doesn't have either of those, it will be fine.
Any high output engine with race ready cam, Voodoo cam, Extreme Energy, or other name brands with a quick ram design and long duration and require heavy valve spring, better have maximum protection meaning Joe Gibbs oil, Brad Penn Oil, Comp Cams race oil, or any number of off road race type oils. I won't say it won't work with standard oil, but I can guarantee it will last a lot longer with high zinc oil.
Joe | | | | | Joined: Feb 2004 Posts: 28,674 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 28,674 | Good points about the diffrerence in stock and high-performance cams, Joe. Another factor that's often ignored is the expected lifespan of some of these engines. The round track engines I built for a lot of years had more "wear" built into a brand new engine than a 200,000 mile street engine. It was routine to run .005" skirt clearance on forged pistons, and .002" to .003" clearance on rod and main bearings. The engine would sound like it was tearing itself apart if it had been run with mufflers. Solid-lifter cams with big clearances were noisy, also. I could hear a gear-drive cam half a track away. With open exhausts, we couldn't hear the hammering coming from the crankcase. Ditto on cams and lifters- - - - -if the cam made 1,000 laps around a 1/2-mile oval without wearing out, we considered the engine a good one. Some survived the whole race season, others got swapped out at mid-year. People who do race engine stuff to street engines should be willing to accept lots of noise, and very short engine life as part of the equation. Race parts assembled with street-engine clearances don't work well, either!
Jerry
Last edited by Hotrod Lincoln; 03/01/2011 6:17 PM.
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