custom AN cam lines
 

I'm making some custom AN cam oil lines.

would it be OK to use this bolt for the oil pressure sensor that'd been modified for AN fitting, or should I get a metric AN adapter for the stock one?

the hole size and placement are different, so I was a bit worried.

https://www.dropbox.com/s/7hjxvd0c9j...jpg?dl=0&raw=1

Wouldn't be that hard to grind a groove in your adapter, just to be sure.

I would like to see you finished product.

Use an adapter. That hole and groove are designed to line up with a very small hole in the sender.

Actually - You could use it. . . . But .. .. The hole is there as a restrictor to fill a chamber and to emulate what pressure a bearing sees. Your bolt would feed Full Line pressure and you'd have a reading that's not actual to the calibration of the sensor.
Not running Carrera tensioners?

hmm, I probably want my oil pressure gauge to be correct tho? :) the AN adapter is cheap enough, just thought it'd be nice to use the all in one piece.

No, Ive done enough research to be confident with the 930 thin boss tensioners (with stoppers) and thicker Carrera idler arms. I recently rebuild the tensioners too:
http://forums.pelicanparts.com/911-engine-rebuilding-forum/901641-3-2ss-78sc-2.html#post9004639

Would there be a market for a custom fitting that would mimic the factory fitting and have an AN fitting on the other for running braided lines?

David

My racecar engine uses non-Carrera tensioners and I replaced the gauges with Autometer stuff. So I ditched the oil pressure sender "block" and the factory gauge sender and that allows me to use AN-4 hose for the cam housing oil feed lines

I replaced the fittings at the engine case with M12x1.00 (not sure on this, have to check) male to AN-4 male adapter fitting. I sealed it with stat-o-seal rubber-aluminum sealing rings. At the cam housings I used metric banjo adapters that are M12 for the banjo bolt and have male AN-4 fittings coming off the banjo body.

https://www.pegasusautoracing.com/productdetails.asp?RecID=6734

I assume the oil pressure sender unit gives an actual value vs the oil pressure switch is just for a warning light?

Im gong to keep the sender block so I can keep my instrument cluster as-is. I can get a straight metric female to -4 male off the block.

I need to look up these "stat-o-seal rubber-aluminum sealing rings", are they required for all AN fittings on engine case?

For the cam housings, I have already tapped the 964 heads for -4 fittings, so I was going to use an 90 deg swivel fitting there. This should work OK?

https://www.dropbox.com/s/6iwb6x8s7f...jpg?dl=0&raw=1
https://www.dropbox.com/s/ky24fhtclu...jpg?dl=0&raw=1

Yep that's correct regarding the oil pressure sender. It is a pressure transducer which provides variable output to the gauge depending on pressure. The oil warning light is just a switch (normally closed) that opens when it sees pressure. The oil warning switch is sorta pointless IMO in that it's pressure/switching threshold is so low (like less than 5 psi I believe) that you're already in trouble if that light is coming on when you don't want it to be on

The stat-o-seal is a rubber-aluminum combination. Not necessary for all fittings. I simply used it because it fits the fitting I used. They look like this


http://forums.pelicanparts.com/uploa...1458664359.jpg

The 90 degree hose end will work good on that fitting you installed in the cam housing. I left the original Porsche adapter fitting on the cam housing to maintain the so-called restriction (or lack thereof) that is placed there beneath the banjo connection. The debate continues as to whether or not restricting oil flow to the cam housings is a good thing or not. Here's just a few of the threads on the amount of oil going to the cam housing

http://forums.pelicanparts.com/porsche-911-technical-forum/202592-cam-oil-restrictor-fitting-why.html

http://forums.pelicanparts.com/911-engine-rebuilding-forum/733469-oil-cam-restrictor-rockers-zddp.html

http://forums.pelicanparts.com/911-engine-rebuilding-forum/335776-3-0-liter-upgrade-horsepower.html

It would seem since you have actual 964 cam housings, your restriction lies beneath your new fitting.

Thanks for those links, I've read most of them.. you're saying the actual oil inlet, as seen here will cause the reduced flow by design in 964 cam tower? Without the need for the adapter with the smaller inlet?

https://www.dropbox.com/s/0vloatkpi2...jpg?dl=0&raw=1

Well its not actually the hole in the cam housing feed tube. On the older cam housings its the fitting that screws into that inlet. In this thread the picture shown in post #17 has the newer 964 cam housing's transfer tube sitting next to the older 911 inlet fitting.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/733469-oil-cam-restrictor-rockers-zddp.html#post7269727

The transfer tube is part #16 in the parts diagram

http://forums.pelicanparts.com/uploa...1458832699.jpg

I have to assume that tube has been removed from your 964 housing in order to adapt it for use in the older 911 engine configuration? That tube is normally used to connect with a bridge piece #21 that brings oil from the crankcase into the chain case. Before the oil gets to the cam housing, it feeds the 964 chain tensioner. This is how the 964/993 3.6 engine does without the external oil lines for the cam housings and Carrera chain tensioners.

http://forums.pelicanparts.com/uploa...1458833014.jpg

So I have to correct myself and say that your "restriction" is determined by whatever fitting you use in that hole, since I was incorrect in saying the transfer tube acts as your restrictor.

The updated old restrictor is a lot smaller and that's where the debate lies. You can see the distinct change in size between the old fitting and the updated old fitting in this post

http://forums.pelicanparts.com/porsche-911-technical-forum/202592-cam-oil-restrictor-fitting-why.html#post1720758

Great info, thanks Kevin!

Im definitely running unrestricted then, with the potential for less cooling through the piston squirters, it seems. Im not sure there is an easy way to add this restriction, if I so choose. The cam towers were modified to be used with those -4 fittings, they were tapped specifically for that purpose. Im not sure what they looked like before (curious, will try to find a pic).

The fitting would allow for full flow, I'd think from looking at it's design. The restriction should only be in the -4 lines.

https://www.dropbox.com/s/tp1dxw21v5...jpg?dl=0&raw=1

KTL, do you have any specifics on the hole size of the restricted pieces? Seems one person averaged the middle point to be ~4.5mm
http://forums.pelicanparts.com/911-engine-rebuilding-forum/733469-oil-cam-restrictor-rockers-zddp-3.html#post7406754

Im thinking I can use a AN-3 line instead, which would provide a similar (middle-ground) restriction of 4.75mm (AN-3) vs the 6.35mm (AN-4) lines I was going to create.

I can't really tell from the pics, but it sounds like the new restriction is closer to ~2mm?

Your adapter will work fine from an oil pressure indication standpoint. The PSI it sees will be the same whether you have a 1/16" hole or a 1/2" hole. The reason oil pressure transducers and switches have tiny holes in them is in case the can blows off the pressure in the galley won't go to zero. The tiny hole restricts the flow exiting the system so there's still pressure at the bearings so you have time to shut it down when you see the oil psi go to zero and the idiot light comes on. So for that reason it's wise to keep the restriction. There's probably some of this same logic involved in the design of the restrictors to the cam oil lines. If a hose blows you lose the pressure to the top end but save the lower end.

finally back at this, after a little hiatus (work and life, you know the drill).

I cannot user the original banjo style fitting on cam tower end, as they were tapped out for the AN fittings. I wanted to use a AN metric adapter off the pressure sender block, since the other tube in the first pic will give me incorrect pressure readings.

I don think there will be much clearance from the sender's tube and the AN adapter! So I either have to ditch the sender unit and find another way to get a pressure reading for my stock gauge, or modify the original pipe; cutting it at the rubber portion and making an AN line from there.

Thoughts or questions?

The older motors had the oil pressure sender mounted on the front of the case, instead of the oil pressure warning light switch. Would that be an option to replace the oil pressure warning light with the pressure sender? Of course my '71 doesn't have an oil pressure warning light.

I have custom cam lines myself, no restrictor so far. Still unsure if I should or not. Oil pressure sender moved to the thermostat housing (no thermostat inside), works fine:

http://forums.pelicanparts.com/uploa...1471515446.jpg

http://forums.pelicanparts.com/uploa...1471515457.jpg

great ideas about moving things around the pressure circuit.

I can do without the warning light and will think about moving it there.

also will look to see if I can get things up in the thermostat blockoff im using from the 965. there are two plugs and I would need to tap the larger M18 plug to accept the pressure sender.

http://forums.pelicanparts.com/porsche-911-technical-forum/904523-964-turbo-t-stat-wanna-block-off-senders.html#post9078869

Maybe I can use the JB racing part 131-035 which is an oil pressure adapter. Im not sure of its thread. The M12 on the 964 t-stat Im using is M12x1.5. But I could see putting the pressure sender and its block off the t-stat is this fits.

otherwise, I'll likely remove the idiot light and put the sender block there.

Roland, how do you control the pressure the sender sees? Per comments above, it's supposed to be calibrated to what a bearing would see.

Well, that's nonsense. 964 console has no orifice either and sensor has one calibrated port built-in.

http://forums.pelicanparts.com/uploa...1471853742.jpg

http://forums.pelicanparts.com/uploa...1471853753.jpg

No need for anything else

Im not clear on the issue, but some seem to think we need to calibrate the flow with that tube that goes through the sender block.

I have the same t-stat but its just hollow inside, so it'll see full flow from the system. The sender I have only has one connector on top for the wiring.

I'll see correct pressure on my 3.0 case if Im to move the sender to the 964 t-stat? Here are pics of me moving it.

http://www.googledrive.com/host/0BwS...zdFMjUzcFNNaTA

wprater:

I think Soy Racer had ingested too much soy sauce when he said that the hollow banjo bolt for the stock location of the oil pressure sensor was somehow calibrated to make the pressure read by the pressure sensor come out right. Several subsequent posts corrected this, and one in some detail (also noting that the sensor itself has a very very small hole letting the oil in, and explaining why, which I had not previously understood).

So just cross Soy's post out on this one. He got that one wrong.

Pressure is pressure. The sender is calibrated so that X amount of pressure pressing on its Y area of diaphragm against a spring of Z rate will move the wiper on a potentiometer a distance which produces the resistance the gauge shows as the PSI or bar pressure in the oiling system.

One engine I bought had, instead of the steel block, just a banjo sandwiched in there with a shorter hollow bolt. Maybe the 2.4s came that way, or some earlier motors? The OP sensor just screwed into the banjo. Plenty of oil flow area, much bigger than that hole in the picture, worked just fine. As does putting the sensor where the idiot sender goes, or into a modified piece (or the 964 - I didn't know they had that) which goes where the thermostat valve for the engine mounted oil cooler goes on 3.2s and earlier motors. Those all see the full pressure the pump puts out against the total flow resistance of the engine (and the relief valves which limit its maximum).

Someone out there surely sells an M12 to M10 adapter, if that is needed. I think some 911 models came with just that for the idiot sender. Look at part 61 in the parts catalog for a '72/3 - 901 101 175.01. It doesn't give sizes. Those years did have the banjo for the pressure sensor.

Me, I've decided the way to go is to weld or braze AN3 fittings onto the stock lines where the crimped on rubber starts. If you bore out these fittings a little bit, and cut off the bulge in the steel line, it will slip nicely inside the AN fitting. Haven't done it yet, though, as I don't really need to (despite having acquired a number of spare stock parts here and there and from Carrera Tensioner kits), and my attempts at brazing have never been all that successful - it never seems to wick up like solder on copper plumbing pipe.

I modified a thermostat valve to be always open (oil always goes to the cooler ports, though I put an oil filter on those ports, not a cooler), and put the pressure sensor there. Worked fine.

A simple solution could be to buy a combined idiot sender and oil pressure sender. The picture showing that fat sender can with two terminals on top is such a sender.

Me, I like to install a 30 pound idiot sender. You can buy an adapter to go from 10x1.00 thread to 1/8th inch IPT, and use an Autometer sender. If you try to screw 1/8 IPT threaded things into the idiot sender hole, you might think it fits, and it might work - once. The threads are almost the same pitch The threads will be mangled some after that, though, as the IPT is tapered, which is how it seals. Porsche used machine threads and a crush washer to do the sealing, which is the way to go.

The issue with the substitute hollow bolt fitting is that its holes won't line up with the hole in the big steel block which holds the pressure sensor. Porsche put that groove there so that the groove would always line up with the hole in the steel block

Walt,

Thanks for the detailed overview! I should have re-read my whole thread after coming back at this, it's clear now that the details of how the pressure system were indeed laid out for me.

Really appreciate all the info everyone in this post has laid out, it's extremely helpful!! Hope this thread will be helpful to others as well.

Im going to move the sernder to the M18 port of the t-stat and keep the idiot sender where it's at. I have all the parts for this now.

Already have my AN lines and adapters on their way and will be putting this all together next week when they arrive. Will update the thread with my completion!!

Cheers,
Will

Good info from Walt as always. He makes a good point about the warning light sender he uses. I'll add to what he's saying & why he's saying it. He chooses to use a 30 psi warning light switch because it gives him additional protection against massive failure when oil pressure is lower than desired. I've been there, seen that in my own engine & I totally agree with what he's getting at. Point being here is that the Porsche warning light switch comes on at nearly zero oil pressure. I don't know the number off the top of my head but it's really low- too low.

Reason Walt mentions the 1/8 NPT thread issue is because he's exactly right. M10x1.0 thread size is so darn close to 1/8 NPT (27 threads per inch) that you can mistakenly think you have one or the other and be wrong.

All the above I shared is moot if you're sticking with the Porsche switch. Just wanted to give you a heads up on the benefit of the higher pressure switch. The downside is that a high pressure switch will typically turn on the light at idle when the engine is warmed up, since the engine usually makes a little more than 1 bar (~14 psi) at idle. So it can be a nuisance to some people to see the light come on all the time. On a racecar/track application, the nuisance is much less and we're always hoping we don't see that light at all when the car is cruising around on the track.

Just tagging along to see how this turns out. I thought I was the only one that cared what that stuff looked like.

Just realized that I never sent an update on my lines that I made! tsk tsk on me.

Ended up moving the pressure sending unit and oil temp to the t-state in the rear of the motor. Removed the idiot light for now, but I could place it in the other block off port of the t-stat, or get awn external unit as Walt suggested.

Here is the end result, but Ive swapped out the fitting for black ones.

http://forums.pelicanparts.com/uploa...1490651098.jpg
http://forums.pelicanparts.com/uploa...1490651098.jpg
http://forums.pelicanparts.com/uploa...1490651098.jpg