[Region Warrior]

Oh crap. 50 ys blocked bypass using delco filters(3 left-they still available?) Straight 30w.oil. Over 60k miles with100' burn outs. Pedal to the floor! Guess 6200 rpm if shift in time...

[Sirrotica]

Originally Posted by KEN CROCIE

For those "on the fence" regarding the bypass, I recommended doubling the bypass spring in the filter housing.

This is what I've been doing in oval track engines after the Lee filter went away in the 70s, in street engines I kept the original spring.

With an 80 lb pump and a doubled up bypass spring, I have pushed oil out of the filter O rung on a cold startup. After that experience I always let the engine idle until the oil thinned out a little bit, that was also running 40 Wt racing oil.

Pontiac isn't the only engine brand where this dispute takes place, chevy guys dispute blocking the bypass valve also.

I have seen the filter elements implode a few times on different brands of filters causing lower end bearing damage. I never felt it was worth the chance to completely block off the bypass over worrying about a bit of dirt reaching the bearings. On the off chance a dozen small bits would reach the bearings it will embed in the bearing material and no major damage will result. If the oil has that much abrasive bits in it that it will totally ruin the lower end, you already have a bigger problem than blocking the bypass valve.

Having run a ton of Pontiacs on dirt, you absolutely will not keep all the grit out of the engine no matter what you do, it gets in there somehow. The air filter would ideally keep out anything larger than 10 microns in theory, but upon disassembly of one of these engines you might be surprised how much ends up inside of a formerly clean engine over time.

I adopted the Frantz by pass oil filters after I quit dirt track racing, If I were to build another dirt engine, or even a good street engine, I would currently use a Frantz, (as Troy, Dragncar, has already said he does) to keep the really small abrasive out of the bearings rings etc. All the oil in the engine gets run through a by pass filter every 3-5 minutes, so every drop is filtered to a sub 5 micron level frequently. if your adding abrasive at a rate faster than that, nothing is going to save that engine anyway, been there, done that.

There are IC engines that have no oil filtering systems used in racing (Briggs and Stratton, and Honda clone engines) that run in go karts on dirt and asphalt that run a long time with no oil filters on them, just frequent oil changes keep them alive. In 1961-63 Pontiac offered a block off plate option on the 194 tempest engine to eliminate the oil filter completely, I've posted pictures of that OEM part previously, so Pontiac engineers obviously felt at one point that if you changed oil frequently enough, the filter could be eliminated, and the engine would still be covered under factory warranty. I've also heard the theory that this option was for those that wanted to install a by pass filter system after they took delivery of the car, by pass filters were pretty popular aftermarket add on in this time period.

The air cooled small engines run in a fairly hostile environment when used in lawn care, and construction, and survive pretty well with just changing oil frequently. and no filter system, something to keep in mind when considering how important a filter system is, or isn't. ROI is a consideration, as is the upfront cost of the engine being protected by a filter system. Mainrtenance downtime is also a factor.

Likely the filter systems modified with no bypass valve are doing little in the grand scheme of things to keep the engine alive. I believe that the people that have adopted no bypass valves feel that they have accomplished something that really doesn't amount to to a hill of beans, but probably is comforting to them, and it likely won't hurt their engine unless the filter media collapses/ruptures, and dumps all the abrasives caught, directly into the bearings all at once.

Keeping the oil analytically clean by use of a by pass oil filter will filter much more dirt out of the engine oil than blocking the bypass valve valve of a standard OEM style filter anyway, (40 microns full flow, 5 microns bypass). You also gain at least 1 quart of capacity as well as there is going to be marginal heat loss from the oil as it passes through the extra plumbing and canister of a by pass filter. it's just a better system to use to supplement the OEM style full flow system already engineered into the engine.

Mu current thought would be use the OEM bypass system unaltered from original, supplemented with a by pass oil filter. Never worry about an implosion of the full flow element, and filter your oil to a standard much higher than any OEM system is capable of.

[SRR]

https://www.youtube.com/watch?v=gSFNpW6kmxc


Do Oil Filters Bypass at COLD START?
The Motor Oil Geek
297K subscribers

[Formulajones]

I don't really care either way. I leave it up to the person I'm building the engine for. Some like it, some dont.

When Bischoff built dads engine 10 years ago he blocked the bypass. It's had wix filters from day one and never an issue with 20-50 oil. It's what Tony did so I left it that way.

On my bird it has a functioning bypass. It's a stock build so I left it that way.

I change oil frequently with good quality oil and monitor with oil analysis so I don't have to worry about it.

[HWYSTR455]

Originally Posted by KEN CROCIE

For those "on the fence" regarding the bypass, I recommended doubling the bypass spring in the filter housing.

Where would one source such a spring?

I 'used to' bend the spring retainer inward, but over time realized that was not a proper approach. I've never found the fiber disc dislodged, but guess that could happen.



.

[HWYSTR455]

Originally Posted by Jay S

I still use a lot of Wix. I am not anti Wix. But Wix’s over all trend seems to be to make them cheaper, not better. I have had may share of issues with them. I have collapsed a couple of them and blown seals out.

The main brands we use are Baldwin, Fleetguard, and Wix (including Napa’s by Wix). I prefer Fleetguard of the 3, then Baldwin. Wix gets used when the other 2 are not options.

Fram makes a very nice well designed race filter. They have a screened bypass. The latest Champion laboratories filters appear to be very well designed to. Hopefully they survive the bankrupcy.

Which Fleetguard part number do you run? I know other non-Pontiac racer-people that run those.


.

[Sirrotica]

Originally Posted by HWYSTR455

Where would one source such a spring?

I 'used to' bend the spring retainer inward, but over time realized that was not a proper approach. I've never found the fiber disc dislodged, but guess that could happen.



.

I removed a used spring from an extra oil filter adapter, then wound the 2 springs together, reinstalled both into the adapter I intended to use.

[Jay S]

Originally Posted by HWYSTR455

Which Fleetguard part number do you run? I know other non-Pontiac racer-people that run those.


.

LF767 for a Pontiac with the OEM filter housing with tight clearance headers.

LF581 when there is more room.

LF3538 when there is lots of room.

The aftermarket filters housing that use the in filter bypass all take a different thread, 3/4” instead of 13/16”. These are common OEM Fleetguard numbers for older GM’s.

[Formulas]

The whole unfiltered oil concept is a little deceiving to me as soon as you hear that most peoples thoughts go to immediate engine death OMG should never happen not one drop, But if you step back from the Clift and analyze the life of a drop of oil, It goes in clean and gets filtered most if not all the time one pass or another because they are designed to keep oil clean so there should not be a chunk of death waiting at the door in case of a bypass and if there is your engine is probably disintegrating at that moment and nearly no filtration system known to man is going to help

[Jay S]

Originally Posted by Formulas

The whole unfiltered oil concept is a little deceiving to me as soon as you hear that most peoples thoughts go to immediate engine death OMG should never happen not one drop, But if you step back from the Clift and analyze the life of a drop of oil, It goes in clean and gets filtered most if not all the time one pass or another because they are designed to keep oil clean so there should not be a chunk of death waiting at the door in case of a bypass and if there is your engine is probably disintegrating at that moment and nearly no filtration system known to man is going to help

I agree, oil going thru the bypass basically never kills parts in the rotating assembly. It may leave a scar in a bearing, or a leave a score some place, but that is about it. Most flat tappet cams the lifter bleed rates are loose enough they can eat some debre and sludge and still function.

I do the filtering upgrades on Pontiac’s when the engine has a roller set up to prevent unfiltered oil that a shard of metal or piece of debre getting in the galley feed. It is extra prevention to keep the lifter’s feed free and clear on roller set ups to prevent collapse lifters and extend needle bearing life. That stuff does not apply to as much to splash fed mechanical lifters or a stock engine.

A secondary reason is after destroying engine bearings, with Pontiac’s stock bypass we did not save any of the roller cam parts when that happened, they galleys are all full of metal filings and everything is a mess. $$$$ of roller parts into the scrap barrel. After we started doing filtering upgrades with either the bypass blocked or higher bypass pressures, the roller valve terrain parts usually can get reused after an engine failure.

[Sirrotica]

To add to Formulas thoughts, the oil that passes through a OEM full flow filter is not filtered to a high standard. Most filter to 30-40 microns, there are lots of smaller abrasives that still pass through the media unhindered. Low concentrations of these contaminants are fairly benign in overall engine health.

The point where the numbers of the 30-40 micron sized particulate start to add up in concentration is what causes the accelerated wear on internal engine surfaces over time. Frequent oil changes will lessen that problem so the concentration is minimized. Blocking the bypass valve doesn't change the facts that a OEM full flow filter is still only capable of filtering out particulate over 30-40 microns. Frequent oil changes are mandatory to keep the concentrations of fine particulate low with an OEM style filter.

Realistically the short burst of oil that meters by the bypass valve in an extreme situation isn't chock full of sand or gravel and going to take out the bottom end in a few seconds, OEM sees it as a non issue. On the other hand starvation of oil for a few seconds, or an internal media rupture due to a pressure spike that dumps all the previously trapped contaminants out of the filter media, will injure the bottom end almost instantly.

The other alternative is adding extra by pass filter that will remove anything over 5 microns and stop the concentration if someone were to run over on an oil change. The by pass filter also allows you to safely extend oil changes as it adds an extra safety cushion by filtering to a much higher standard over a longer period.

Again, small engines depend upon frequent oil changes to keep the concentrations low the same as automotive engines used 1000 mile oil changes before the addition of any oil filter systems to automotive engines. The addition of oil filters in automotive applications moved the 1000 mile intervals to 3000 miles by at least removing some of the contaminants.

In the end no oil filter, or blocking a oil bypass valve is going to stop catastrophic engine failure by itself. The main job of a filter system is to keep contaminant counts in the lower ranges to head off long term wear until the oil can be changed for fresh oil, or there is a by pass filter system installed that removes nearly all the small contaminants, all the time.

So you can improve the system to filter to a higher standard, or change oil frequently because it's getting contaminated constantly by small particulate that no OEM system can remove. No rocket science involved, just choices on what system you run.