hey guys wondering if an one on here could answer this question for me. ive turbo'd and built a lot of zetec engines. i use an oil galley plug on the side of the head for the oil feed on those engines.

i noticed on these forums that every one uses a type of tee to the oil pressure sending unit. i had my bp out today putting a stg 2 clutch in and noticed this plug below the cas...



any one know if this is oil galley plug with pressure behind it?

Thanks
Tim

 

Judging by this diagram it would seem that plug would be blocking off the exhaust side gally the feeds the valve train on the side of the head.



Now whether the head has a restrictor built into it I'm now sure, you could always put a gauge there and check it after you get the engine back in and inform the rest of us poor souls

I'd personally like to know cause I swapped and entire 99 engine into my 94 so I was looking at having to go the sandwich plate route for an oil feed, but I'd rather not if I don't have to.

 

I always use it.

I've probably turbocharged... 20 or 30 miatas using that plug.



Dann

 

i seriously doubt there would be an kind of restrictor used on a galley that feeds the head. i may put my oil pressure gauge and turbo feed from there any way.

awesome. thanks Dann. exactly what i wanted to know. is it like a 1/4" npt used on that?

nice looking setup on that build. really like the intake

Tim

 

1/8" bspt which is also known as 1/8 g

 

If people are T'ing off the oil pressure regulator, it is because they don't have the plug on the side of the block drilled and tapped. For the '90-'96(?) blocks, there's an easy bolt you can remove and thread into.

This is what FM, BEGI, Greddy, and 90%+ of the MT members (with that bolt) use. I'm not saying anything bad against Dann's method, just another consideration.



I've tried to find a picture of the undrilled block, but I can't. You get the picture though, some later blocks just aren't drilled and tapped.

 

Not a great shot from that perspective, but you can see the two undrilled bits on my block just behind the DP outlet casting:



Not sure what year the block is -- I bought it from FM along with the Supertechs that it had been machined for.

--Ian

 

Excellent! I was worried I was going to need either a sandwich plate or a tee on the oil pressure sender - extra areas for leaks I wasn't looking forward to.

Thanks Dann

 

Hmm i'm curious why begi and FM use the pain in the butt method that tees off the oil pressure sensor when theres an easy to get to plug on the back of the head.

 

Not sure, but looking at that diagram I noticed there is an "oil control plug"

Anyone have any ideas on whether that reduces the oil flow/pressure to the head? Maybe Corkey knows something we don't (very likely)

 

I'm actually a bit paranoid about using that plug for oil feed as well. We discussed BP heads in other threads and it was confirmed that there's a restrictor pill in the oil passage between block and head, so it might not be the best idea to draw a bunch of oil away from the head after its already been limited.

FM and Begi have boosted miata's for decades and don't use that port either. And if you were to slightly starve your valvetrain of oil I bet the consequences won't likely show up very quickly, but you may potentially damage things long term. Who knows.

 

Chalk me up as another skeptic. I think if that was a good option FM/Begi would use it. I will say the oil feed under the intake with the oil pressure sensor was my least favorite part about installing my FM kit. So if this is an option with no negative impact to oil pressure at the head, I'm pissed FM isn't doing this.

 

Looks like sandwich plate it is then. :(

 

since the bp is hydro lifter if you were running low oil pressure in the head bc of this you would get lifter noise. and since dann said he has did 20 set ups this way and he hasnt had any problems i'll use it. the zetec has a restrictor between the block and head to and we all use its oil galley plug in the head.

and my car is a 97 bp so it doesnt have that plug in the side of the block.

Tim

 

Get ur oil from the pressure sensor with a T fitting.

 

Not sure if its myth or not but it seems like I've heard of the tee fitting failing when used with the larger oil pressure sending units from 89-94

 

If u're that worried about it run it to the T fitting with a flexible hose, then have the sensor on the T fitting so you can secure it to the bottom of the intake manifold and then continue running it to the turbo.

In other words instead of having the T fitting hard mounted to the block use a hose instead and just secure the new larger oil pressure sensor to the intake or the block.

 

In that case, place the Sensor+T on the FW since you are on the way to the Turbo anyway.
The FW vibrate much less.

How is it on a VVT engine, is it wise to steal oil from the VVT feed line (which is where the pressure switch sits)?
The banjo into the block is quite big though.

 

vvt engines source their vvt oil separate from the head (from the pressure switch like you said) so that should also tell you something about taking oil from the port in the head

that said, there's nothing wrong with tapping into the vvt line, since its not limited

 

I'd recommend that if anyone does ever use the back of the head as a source for oil for the turbo, that when they pull the plug, make sure to clean out the galley really good before you just screw your feed line into it.

That plug has probably been closed for well over a 100,000 miles on many of the cars here with out ever being removed. The last head I went through that was rebuilt by a "professional shop" didn't even open them up and there was sand inside the galleys presumably from the media blasting process at one time.

Other than that I would be on the side not seeing much of a problem with running a turbo feed line from here as Dan has done many times. And I think that the issue is even less of an issue with the later motors which all have solid lifters that don't need to be, pumped up.