Anti-drain back valve

[westex39]

In checking out Amsoil filters for my application(chevy 5.3L engine)I found out that the SDF64 filter does not have a anti-drain valve. However, the AC Delco PF59 which is the regular equipment filter does. I also checked on a Baldwin #B1432, Hastings LF487, & a Mobil 1, M1-206. All of these are replacement filters for this engine and they all have the anti-drain back valve. I wonder why the Amsoil filter doesn't. Does anybody have any ideas?
Thanks.

 

[KCDoug]

I think I heard that Baldwin make the Amsoil & Hastings filters, so what you've found is real interesting. I've found similar results for my cars. Unfortunately, I don't have a good answer for you.

 

[SteveD2]

Your engine does not need a bypass valve inside the filter. Amsoil only has two filters with the 13/16-16 thread that you need which do not have the internal bypass, and neither has the anti-drainback valve. So...they don't offer what you want.

Does your filter mount straight up with the threads on top? If so, the oil isn't going to drain anywhere. If not, I wouldn't use the Amsoil filter.

Ken

 

[dickwells]

Filter orientation has nothing to do with the need for an anti-drainback valve. Its the oil up in the passages to the cam, lifters, and bearings that are allowed to drain back with no valve and must be refilled before the critical areas have lubrication. In modern engines this is very important since they tend to start at the first turn of the engine, unlike older cars which turned over enough times to allow oil pressure to build before firing off. That said, of course its worse with the filter mounted sideways because you can lose all the passage oil plus half the filter oil with no backdrain preventer. RW

 

[westex39]

I checked the Amsoil filter cross reference book and found that the SDF30 has the same dimensions except it is about 3/4" longer and has the by-pass valve set at 7 to 9 psid. It also shows it have the anti-drainback valve installed. The filter applications that I could find for the SDF30 were for a Chevy 307 cid and a 5.7L diesel back in the 1980's. What do you guys think about using this filter for my application (2001 Chevy 5.3L)

 

[SteveD2]

quote:

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Originally posted by dickwells:
Filter orientation has nothing to do with the need for an anti-drainback valve. Its the oil up in the passages to the cam, lifters, and bearings that are allowed to drain back with no valve and must be refilled before the critical areas have lubrication. In modern engines this is very important since they tend to start at the first turn of the engine, unlike older cars which turned over enough times to allow oil pressure to build before firing off. That said, of course its worse with the filter mounted sideways because you can lose all the passage oil plus half the filter oil with no backdrain preventer. RW

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Won't the oil from the upper portions of the oil system drain down and out the oil ports in the lower part? Won't the oil from the cylinder head drain back down and out the oil ports in the crankshaft?

Ken

 

[dickwells]

In my experience, mostly with small block chevys and using Pf-58 compared with PF-59s (with and without the backflow valve) the oil takes much longer to leakdown, like days, with the valve, where they will rattle on startup the next morning without the valve. Just the way it looks from my warped view of the world.

 

[Patman]

So then you highly recommend I start using the L34631 filter on my 350 LT1, since it has an antidrainback valve? I'm currently using the L30040 oil filter, which is the same as the L34631 other than not having the antidrainback valve.

I never used to think it was necessary on a filter that is mounted downwards like that. Although I then wonder why GM still specifies the PF44 filter for the Corvette, as that filter has no antidrainback valve.

[ September 23, 2002, 02:49 PM: Message edited by: Patman ]

 

[dickwells]

I don't know Patman. Those are Pure filter number aren't they? Do your lifters rattle the next morning? (if they are hydraulic) I certainly have heard rods knocking in Corvettes on cool mornings, but that was long ago. How about GM rolls the dice and says that on a high performance engine that is likely to see the redline quite often, they would rather take the slightly higher oil flow with no restriction from a backflow valve. I figure when most of these engines hit the boneyard at a relatively early age the wear will be redline wear rather than cold start wear. Just goes to show you need to look at each situation separately. Regards, RW

 

[Patman]

I don't plan on running the PureONEs actually (too restrictive for hard driving IMO) those are the regular Purolators. My lifters do not rattle at all on a cold start ever.

 

[Patman]

I was wrong above. I just found out that the PF44 filter does have an antidrainback valve in it too.

 

[dickwells]

Thanks for the update. I just read today on another site that there was a TSB for GM 4.3 sixes that rod knock on startup could be cured by getting a filter on that had a check valve. I think that this was in the early 90s series. RW

 

[Al]

As much as I would like to argue to the contrary. I think the oil clatter on startup may not be that significant. I say this because I had a 2.3L (Can you say weak engine) Ford Pickup with the horizontal filter mount that I used the Delco PF 8 filter (no anti-drainback valve). That thing rapped for years on startup. And then to boot, the red light stayed on for 30 seconds or so on startup (Dealer said-normal)

Finally determined that the oil pump screen was 90% clogged. 150K and the thing is still going strong. Friend bought it.

 

[dickwells]

I guess the answer would be to analyze the oil from two comparable engines, one with checkvalve and one without which raps on startup. Bearing material should tell the tale. Of course to be sure a "statitistically valid" sample would have to be run with the engines switched back and forth to confirm the results. For myself, I don't like hearing my engine rap or having people look at me like I am stupid in the parking lot. RW

 

[RobZ71LM7]

You NEED an anti drainback valve on the GM 5.3L's. They originally came with PF58's which lacked this valve and that resulted in start-up noise from a dry valve train. That was fixed by the PF59.