[The Champ]

Originally Posted by Tom Vaught

So again they ASSume certain things with no real knowledge or facts.

Look in the mirror when you say that.

You ASSume that Lake Speed Jr. doesn't know what he's talking about with no real knowledge or facts.

You instead depend on what some BP oil person told you 2 or 3 decades ago. Technology changes. Maybe your self proclaimed "knowledge or facts" are no longer valid.

You can always tell an engineer, but you can't tell him/her much...

[78w72]

Originally Posted by chiphead

I'm doing a cam swap in a 400. For breaking in a HFT cam, would you guys use Rotella T4 conventional or Rotella T5 semi-synthetic? Rings are already seated, as this engine has been together a long time.

break in oils are better for this than normal oils, but there is another option that is cheaper with as good or better additives for new cam break in, use a cam break in additive like comp, crane or lucas added to a good brand of off the shelf oil. break in oils can cost $8-$10/qt & you dump it after break in or very low miles, the additives are about $10-20 & designed for this purpose.

either one will work but the additive seems like a better option IMO, ive used the comp break in additive with a name brand oil for 2 of my new cams, along with break in lube on the lobes/lifters & proper start up & break in procedure. both went great & lasted for 80-100k miles on one before pulling the engine & selling the car & going on 13 years & many miles on the other. i used older SL/SM rotella t for awhile on the current FT engine & delo 400 as well with no known issues, now i use a good brand of normal oils in 2 FT engine cars with no additives or crazy high zddp levels because the cams are smaller with not very strong springs & already broken in. also ran a FT cam jeep 4.0 engine as a daily driver for 17 years using whatever oil was on sale, usually supertech & cheap spin on filters, went to 200k+ miles & is still running around town today with probably 250k+ miles 3 years after i sold it.

rotella & other diesel oils arent what they used to be even 10 years ago, for a critical cam break in its best to use a specialty break in oil or an additive with a good brand of normal oil & not synthetic for FT cam break in.

[Steve C.]

Rhetorical question.... Is Brad Penn oil 'better' than Driven Racing Oil ?

Both use Pennsylvania-grade base oil and have enhanced zinc and phosphorus packages.

Both are designed to meet the requirements of specialty applications like drag racers, hot rods, oval track racers as well as vintage, muscle and classic car enthusiasts.

Both promote their products on the internet !


.

[MatthewKlein]

I haven't read every post in this thread but thought I'd add something.

Carbureted engines are over fueled compared to modern fuel injected engines. The extra fuel washes down the cylinders/rings, dilutes the oil and is the main reason modern engines last so much longer.

Changing the oil is the only way I know of to remove that extra fuel.

[Formulajones]

That's another example of why I like oil analysis. You'll know if your oil is saturated with fuel and can base your oil change intervals accordingly, or work on the tune up.

[MatthewKlein]

Originally Posted by Formulajones

That's another example of why I like oil analysis. You'll know if your oil is saturated with fuel and can base your oil change intervals accordingly, or work on the tune up.

An ideal carburetor tune up is going to over fuel compared to fuel injection. There is no way around it. For me, stretching oil changes is not worth it. Especially on antique vehicles.

Over the past few years we have started to see engines using oil. For the longest time it was a non issue. Part of the equation is low tension piston rings. The other is extended oil change intervals recommended by the OE.

It's just not worth it to me personally.

[Formulajones]

Originally Posted by MatthewKlein

An ideal carburetor tune up is going to over fuel compared to fuel injection. There is no way around it. For me, stretching oil changes is not worth it. Especially on antique vehicles.

Over the past few years we have started to see engines using oil. For the longest time it was a non issue. Part of the equation is low tension piston rings. The other is extended oil change intervals recommended by the OE.

It's just not worth it to me personally.

The idea, with the oil analysis, is that you aren't harming the engine by stretching the oil changes, you're only saving money by not changing it more often than needed. It just helps determine if the oil life has run it's course. It also gives a little insight as to how the engine is doing and if the oil and the filter you're using is doing what it's supposed to do, or even has the ingredients in it that the manufacture states.

On carbs, honestly, an ideal carb tune shouldn't over fuel the engine. If you're pretty intricate with the workings of a carb you can tailor the AFR pretty darn close.

On our daily drivers, they are carbed, one a holley 780, and the other a Q-jet. Oil analysis have shown the oil and filter combo I'm using is reaching on average about 5500 miles before it's time to change. That's not huge but it's better than the 3000 mile intervals I've always done. Saves me time and a lot of money with a dozen vehicles to worry about and no ill affects to the engine at all.
Every car may be a little different, and different oils and filters will alter that time frame as well. No way of knowing without sending off a sample.
Just stretching the oil changes without a analysis just because the manufacture says so is like shooting at a target with your eyes closed. You won't know if you're doing any good or not.

[MatthewKlein]

Originally Posted by Formulajones

The idea, with the oil analysis, is that you aren't harming the engine by stretching the oil changes, you're only saving money by not changing it more often than needed. It just helps determine if the oil life has run it's course. It also gives a little insight as to how the engine is doing and if the oil and the filter you're using is doing what it's supposed to do, or even has the ingredients in it that the manufacture states.

On carbs, honestly, an ideal carb tune shouldn't over fuel the engine. If you're pretty intricate with the workings of a carb you can tailor the AFR pretty darn close.

On our daily drivers, they are carbed, one a holley 780, and the other a Q-jet. Oil analysis have shown the oil and filter combo I'm using is reaching on average about 5500 miles before it's time to change. That's not huge but it's better than the 3000 mile intervals I've always done. Saves me time and a lot of money with a dozen vehicles to worry about and no ill affects to the engine at all.
Every car may be a little different, and different oils and filters will alter that time frame as well. No way of knowing without sending off a sample.
Just stretching the oil changes without a analysis just because the manufacture says so is like shooting at a target with your eyes closed. You won't know if you're doing any good or not.

I appreciate the science and effort you are putting into this. But I respectfully disagree.

If carburetors could meter the fuel efficiently enough automakers would never have gone to fuel injection. Fuel injection is astronomically more complicated and expensive.

Factory tuned carbs on mild factory engines specified to pass emissions were as good as it was gonna get. They over fuel and wear engines out much much sooner than modern OE fuel injected engines. It's not up for debate.

Also, I love carburetors. In no way am I lobbying against them. I just understand their shortcomings.

[Formulajones]

The one thing I'll give fuel injection is that it's much easier to tune and I can get a bit more precise with my changes. But in the end I can pretty much accomplish what I want with a carb and be perfectly happy. I don't have engine longevity issues or drivability problems. They are simplistic and cheap.

The issues really these days is that it's a dying art, with people less interested in them and few people around that even want to understand.


I guess where I'm a bit confused is when you say "over fuel" I'm not sure I'm understanding that correctly. I mean, an AFR number is an AFR number no matter how it's metered. I guess I'm trying to simplify this for those reading.

In other words, if I have the carb dialed to cruise at 14.0 AFR, and I have the other car with EFI programmed to run a 14.0 AFR, where is the over fueling?

As an example, we have 2 cars here with Holley EFI. These engines want what they want for fuel. One makes best power at WOT with a 12.4-12.6 AFR so that's where I have the EFI programmed to run. They also cruise with an AFR of about 14.0-14.2 and that returns respectable gas mileage while not going overly lean. I can basically set a carb up to do the same or very similar. Where the carb loses is the drastic elevation changes we deal with. While atmospheric pressure will change how the air pulls across the boosters and compensate this to some degree, it's not a cure all. EFI with it's ability to change on the fly is wonderful in that respect. EFI has a few drawbacks too, cost and complexity being a couple.

But I've had no issues with over fueling with carbs, as far as the tuning aspect goes using AFR numbers and reading spark plugs. My oil analysis don't show excessive fuel.

Is there another aspect of this I'm missing that you're trying to explain?

[MatthewKlein]

Originally Posted by Formulajones

The one thing I'll give fuel injection is that it's much easier to tune and I can get a bit more precise with my changes. But in the end I can pretty much accomplish what I want with a carb and be perfectly happy. I don't have engine longevity issues or drivability problems. They are simplistic and cheap.

The issues really these days is that it's a dying art, with people less interested in them and few people around that even want to understand.


I guess where I'm a bit confused is when you say "over fuel" I'm not sure I'm understanding that correctly. I mean, an AFR number is an AFR number no matter how it's metered. I guess I'm trying to simplify this for those reading.

In other words, if I have the carb dialed to cruise at 14.0 AFR, and I have the other car with EFI programmed to run a 14.0 AFR, where is the over fueling?

As an example, we have 2 cars here with Holley EFI. These engines want what they want for fuel. One makes best power at WOT with a 12.4-12.6 AFR so that's where I have the EFI programmed to run. They also cruise with an AFR of about 14.0-14.2 and that returns respectable gas mileage while not going overly lean. I can basically set a carb up to do the same or very similar. Where the carb loses is the drastic elevation changes we deal with. While atmospheric pressure will change how the air pulls across the boosters and compensate this to some degree, it's not a cure all. EFI with it's ability to change on the fly is wonderful in that respect. EFI has a few drawbacks too, cost and complexity being a couple.

But I've had no issues with over fueling with carbs, as far as the tuning aspect goes using AFR numbers and reading spark plugs. My oil analysis don't show excessive fuel.

Is there another aspect of this I'm missing that you're trying to explain?

The whole time the engine runs on choke it over fuels.

I don't know how you track the air fuel ratio but unless you have a data logger I'm not sure how you know what the ratio is at all times. Every time the accelerator pump discharges its messy and over fuels.

The only time a carb runs at a constant air fuel ratio is at a steady load. Similar to an aircraft carb. Or a stationary pump.

The constant transitions in engine load an automobile requires to accelerate from a stop, pull hills, etc make it impossible for the carb to provide tight enough fuel control to maintain stoichiometry and not to contaminate the oil.

[Jay S]

I think it depends too on the type of fuel injection, MPFI keep oil cleaner with less dilution, a result of less wet flow. Throttle body or a well set up carb should not make much difference on oil dilution?

When additive packages are constantly changing the oil analysis will catch the change.

I think I read the pros and cons of diesel oil for break in oil a couple post up? Good break in oils should have very very little detergents, which on an oil sample is most represent by Calcium, i don’t like to see Calcium more than 1000 ppm for break in oil. It is because the calcium scrubs the wear additives off of metal parts, exactly what you do not want on an engine break in. Plus you are changing the oil very soon anyway, there are no reason to have much for detergents to extend an oil change. Diesel oils generally make TERRIBLE break in oil, with calcium well over 2000 most of the time.

Driven, Brad Penn, Valvoline VR1, or Amsoil z rod all may have very similar Zinc and Phos, the bigger difference in those oils is often calcium.

[Dragncar]

Originally Posted by MatthewKlein

I haven't read every post in this thread but thought I'd add something.

Carbureted engines are over fueled compared to modern fuel injected engines. The extra fuel washes down the cylinders/rings, dilutes the oil and is the main reason modern engines last so much longer.

Changing the oil is the only way I know of to remove that extra fuel.

A properly set up Q Jet is very close to fuel injection.
The main reason engines last so much longer today has to do with far better machining process.
I got 20 mpg in a 63 Willys Wagoner with a straight 2 and a Holley 2 barrel.
Today,s heavy SUVs are about the same. Most, worse.

[Schurkey]

Originally Posted by Dragncar

A properly set up Q Jet is very close to fuel injection.

Emissions-style port feedback fuel injection beats the Q-Jet when the engine is cold/cool. Beats the Q-jet when the manifold doesn't have good fuel distribution.

The Q-Jet kicks ass on the port, feedback fuel injection at cruise. F.I. is set up to run at stoich, the Q-Jet can be run significantly leaner (at a sacrifice in NOx emissions.)

Some GM vehicles that are exported to countries with lax NOx regulations have "Highway Lean Cruise" built into the computer programming, allows the mixture to lean out under certain conditions. Perhaps other automakers have similar fueling strategies.

Originally Posted by Dragncar

The main reason engines last so much longer today has to do with far better machining process.

And overdrive transmissions with additional gear ratios that overall produce lower rpm per mile, better oil, and lack of over-rich choke when cold.

Originally Posted by Dragncar

I got 20 mpg in a 63 Willys Wagoner with a straight 2 and a Holley 2 barrel.
Today,s heavy SUVs are about the same. Most, worse.

Eliminate the NOx regulations, cut horsepower in half or perhaps to a third, drop curb weight by eliminating structural strength, air bags, on-board backup cameras, touchscreens, DVD players for the kiddies, wide tires, big brakes, etc.--watch fuel economy climb.

[Formulajones]

Originally Posted by MatthewKlein

The whole time the engine runs on choke it over fuels.

I don't know how you track the air fuel ratio but unless you have a data logger I'm not sure how you know what the ratio is at all times. Every time the accelerator pump discharges its messy and over fuels.

The only time a carb runs at a constant air fuel ratio is at a steady load. Similar to an aircraft carb. Or a stationary pump.

The constant transitions in engine load an automobile requires to accelerate from a stop, pull hills, etc make it impossible for the carb to provide tight enough fuel control to maintain stoichiometry and not to contaminate the oil.

Yes I data log everything.

You do realize even EFI has cold start tables? They don't run at stoich when cold, they add fuel until the engine is up to temp, much like a choke on a carb.
In fact many of us here that tune EFI could show you the fuel tables on a cold engine. Each engine is different but in most cases you'll see afr's well into the 12's on a cold start with EFI. It's really no different other than it's controlled a little more precisely.

[Formulajones]

As far as gas mileage, it's pretty simple to accomplish with a carb.

My 69 Z got 17 mpg highway with it's factory DZ and 780 Holley on top. I added a tko600 and the additional 5th gear gets me 21+ now.

My 70 RAIII formula gets 17 still using a 400 turbo, no overdrive.

My 454 Chevelle that makes 600hp gets just over 17 with a 4l80e and 4.10's out back.

And dad's gto with a 571 making over 700 HP just got 16 mpg with a 4l80e and 3.42's out back.

Most SUV's on the road today barely do this good.

I have these cars set up to run only about 14:1 afr. I don't run them super lean. In fact stoich with today's ethanol fuel is 14:1 anyway, not 14.7 anymore unless you find some real gas.
What some don't realize is running them super lean will give diminishing returns. Start pushing them up past 15:1 and you'll find more throttle angle needed and the engine working harder to maintain speed, fuel mileage suffers.

To keep this thread somewhat on track, none of the afr's above have given me any diluted oil issues and the engines have been running for years, some have been together 25 or more years. I use a good oil and filter and monitored with oil analysis to give me a good change routine that works. It's nothing extravagant, just simple maintenance on engines that are sharply tuned.

[Formulajones]

Originally Posted by Dragncar

A properly set up Q Jet is very close to fuel injection.
The main reason engines last so much longer today has to do with far better machining process.
I got 20 mpg in a 63 Willys Wagoner with a straight 2 and a Holley 2 barrel.
Today,s heavy SUVs are about the same. Most, worse.

That and the fact that today's vehicles all have overdrive and loaf around at low rpm all the time certainly helps longevity.

People forget we daily drove these classics around back in the day running 3000 rpm everywhere. That's wear and tear.
Put an overdrive in and you have a game changer.

[Jay S]

We have a variety of different fuels with different injection methods powering engines here. Gas, Diesel and propane with carbs, TBI, MPFI, direct injection, electronic direct injection, and stupid simple fuel mixers. Just my opinion, but I think the diesel oil became popular on the carb’d engines because the oil does not stay very clean very long, and they like the combo of antiwear additives and extra detergents to extend the miles between oil changes to decent intervals. Metal hardness has been creeping down in camshaft components, and need more and more protection, the diesel oil might be the best choice anymore if you need more protection for that stuff. But oil can only take things so far when the metal is junk.

To me there is no question the fuel type and fuel delivery method make a difference on engine life and oil, and best results are usually not with the same oil on everything. The electronic direct injection make a pretty remarkable difference on cylinder wear. It use to be on over the road trucks we would need to do an inframe OH at 700,000 miles, with a combination of a lot of different tech, some OTR engines more than doubled that now. My propane engines run non-detergent oils. The oil always looks new when it is changed, and oil analysis reflects that also.. As good or better than any modern fuel system. On wet fuels, anything below some type of direct injection has an impact on washing cylinders with fuel, and eventually get to the oil.

I have not had much better luck with the “modern machining” than the old school machining. It almost never fails that something in the modern engine fails not long after the old engine.

A few months ago I found a 78 Trans Am for sale with a W72 that had 320,000 miles on the original untouched engine, bought new by the owner. Highest milage I have ever seen on a Pontiac. I wanted to buy it but my wife would kill me. Lol

This fall a friend came across an early 2000s Ford F-150 that had 670,000 miles with the engine untouched, he took a picture of the odometer. He told him Ford should give him a new pickup for driving it that long. Hard to read, but here is photo he sent me, pretty impressive.

[Formulajones]

The funny part is everyone seems to be worried about longevity on a classic car site, based on vehicles that no one drives more than a 1000 miles a year LOL

Dad bought his 69 goat new (still owns it) and had 180,000 miles on the original engine before he got the bug to go faster and pulled it for something bigger. Was still running fine.

We are still daily driving old cars with carbs and points. Call me antique, but I have absolutely no concerns about longevity, the cars will probably outlast me, and frankly don't really care if a refresh is in my future. I'll build it and continue..... But I won't be running any diesel oil in them Just sayin

[78w72]

Originally Posted by Jay S

A few months ago I found a 78 Trans Am for sale with a W72 that had 320,000 miles on the original in touched engine, bought new by the owner. Highest milage I have ever seen on a Pontiac. I wanted to buy it but my wife would kill me. Lol

This fall a friend came across an early 2000s Ford F-150 that had 670,000 miles with the engine untouched, he took a pick of the odometer. He told him Ford should give him a new pickup for driving it that long. Hard to read, but here is photo he sent me, pretty impressive.

there are toyotas & other modern cars going to 300-400k on a regular basis & some to 500k-1 million miles... all with normal oil filters & oil change intervals.

i'd be willing to bet that the t/a didnt use any specialty "hot rod" oils or crazy amounts of zddp additive for its FT lifter/cam either.

[Jay S]

Originally Posted by Formulajones

The funny part is everyone seems to be worried about longevity on a classic car site, based on vehicles that no one drives more than a 1000 miles a year LOL

Dad bought his 69 goat new (still owns it) and had 180,000 miles on the original engine before he got the bug to go faster and pulled it for something bigger. Was still running fine.

We are still daily driving old cars with carbs and points. Call me antique, but I have absolutely no concerns about longevity, the cars will probably outlast me, and frankly don't really care if a refresh is in my future. I'll build it and continue..... But I won't be running any diesel oil in them Just sayin

Lol. That is so true. A lot of us have multiple car to drive too, we don’t stack on that many miles on classic stuff.

My friend that sent me the shot of the ford 150 with high miles recently swapped out his 1.65 rocker arms to 1.5s on his GTO because he was afraid of the extra wear and tear, which was not a bad idea. The bigger rockers were not really helping anything on his car. But honestly no more than his GTO gets driven he could have a .800” lift solid roller cam in it and never have a issue.