Bypass filter on GM

[oilforfun]

Hi,
What makes GM cars different in regards to a bypass filter installation? I have been reading some posts, and they mention the location of the factory bypass valve as being a problem.

What needs to be done in order to make sure that a GM car or truck has the filter function properly?
I would like to do a GM truck with a permacool sandwich adaptor and a Ralph Motorguard. Would I encounter any problems with this combo?

Thanks,
Oilforfun

 

[Shaman]

Many GM's have an internal bypass, which means that a pressure change will change before the oil filter, aka before the sandwich adapter that you put on.

 

[oilforfun]

Hi,
So how do we avoid that? What would be the correct way to do the installation in that case? How would I know if my car is set up like that?
Thank you,
Oilforfun

 

[Gary Allan]

You plug the bypass mechanism and use a filter with a bypass valve in it. They're available. If you're remote mounting, you use the Ford mount anyway.

That's one way, anyway

 

[canadiantim]

Traditional GM has had this internal bypass but they have a variety of engines in use now - including those made by Toyota and Honda which obviously don't have this style bypass.

I've seen info online while researching sandwich adapters regarding eliminating or modifying the sensitivity of the internal bypass for use with remote filters, coolers, etc. It didn't apply to my situation so the details didn't stick. I have an earlier 350 in my Vette and it has separate pressure and return ports for adding a cooler. If the truck is rated for heavy duty, it may have these ports already. There's probably a truck forum that would have this info or check with the dealer.

Do some research into your particular motor to see what you're dealing with. Even with the truck I wouldn't assume the bypass is internal. Odd's are it IS but consistency is rare these days so you're best to confirm. Maybe start a post specifically about adding a Permacool to your model truck.

 

[johnd]

I would think that it would work even without plugging the internal bypass filter. The internal bypass is there to ensure that oil pressure is not too high. Once it closes, oil will flow to and through adaptor mount and it's bypass, through the full flow filter and return. The second bypass valve provides the slight pressure to feed the bypass filter. As Ralph usually points out, if the end result oil pressure is not high enough, the mount can always be drilled.

 

[Gary Allan]

johnd ..the in block bypass is for the filter without one. The "relief" valve that you speak of is in the oil pump. This is what would limit oil pressure.

 

[canadiantim]

At what pressure would this internal bypass start to bypass the full flow filter? Some of these engines use factory remote filters so I'm suspecting the bypass threshold is higher than within a FF filter to allow some tolerance?

I'm wondering if the MG and Permacool might operate below this level so might still work fine - at least with warm oil?

At steady state I would think that the internal bypass would really only see the pressure/resistance of the FF since the poppet in the permacool should adjust flow for the Motorguards resistance making it virtually invisible to the internal bypass?

 

[Gary Allan]

canadiantim

The permacool, in most installations (Ralph has reported and I confirmed for myself since I though he was FOS - I was WRONG), maintains a 2psi differentail across the sandwich and whatever is routed around/through it. This would not be what the internal bypass would see since there would be the Permacool/bypass and the ff filter that it would be "seeing" across.

I don't know the rating of the GM spec's for this internal bypass ..and I'm sure that they vary from engine to engine (or installation to installation) due to things like the remote setups and the size of the lines ..etc. IIRC, some of the SBC bypass settings were quite low. So if you get 2psid from the Permacool (assuming that your oil pump output is not too high volume) and another 2-3 psid with the ff ...

 

[canadiantim]

Oilforfun, any luck with the install or planning stages?

 

[oilforfun]

Hi,
The Motorguard was given as a Christmas gift to my brother. He should be installing it in his 2006 H3 shortly.
I will check in with the results when they become available.
Thanks for the help,
Oilforfun

 

[1977c10phxdriver]

Just a word of warning. Lots of the car manufactureres are getting very tough on aftermarket items and warrantee work. They seem to go out of their way to deny service when ever possible, specially if they find something on the engine that changes the oiling system or the air induction system, like oilable air filters and bypass oil filters.

Mark