To get further to the bottom of this to prevent anyone else from having potential problems, I wanted to start a new thread on this to get more exposure.

If you have a turbo'd Gen I sbc, where did you get your oil feed from and have you had any problems relating to it?

My L98 developed a rod knock very shortly after I TT'd it (without beating on it too hard), previously the engine had no problems like that for around 2000+ miles. The thoery at this point is that the location from which I took the oil, the old-style pressure sender port, is upstream of the rods and mains, therefore taking oil that was needed by the rods and mains. Not all of the oil mind you, but enough to starve them at idle when the pressure is low, at least. I had no restrictors on the turbo oil inlets, so both of them inhaled all the oil they could.

I could be wrong about this and actually have another problem, but it would be a mighty coincedence and there have been a few others that reported very similar problems with their setups taking oil from the same place.

The only proven alternative on the newer blocks that I know of is where the new-style pressure sender is located. I've heard of a couple who T'd it from here, and have had no problems for many many miles.

If you have any information or insight, please post up!
Edit: Also, please post your block year, number of miles, type of oil pump, number of turbos (heh) and whether or not you're using restrictors.

 

I have the oil feed like you, at the top, rear of the block. (next to distributor) Single turbo, 1991 L98 block, 140,000 miles on it, 7,000 miles on rebuild (stock crank), High volume oil pump. No problems at all for over 7,000 miles. No ristriction in the feed line. My oil pressure at idle is around 30-35psi. It usually is 50-60psi while driving.

 

1991 GTA LB9, AT, single turbo, restictor (valve type), oil taken from right next to the oil filter at that sending unit. 120k on it before the turbo, so about 135k on it now. My turbo blew the seal right off if I didn't have a restrictor. When I opened it up the seal was completely gone. But my engine is fine. Oh, and stock oil pump

 

When do you need a restrictor? I assume it's just a metering orifice?

 

-1975 Van/Truck block
-27k miles since bore/rebuild
-melling high volume/ high pressure oil pump (verified 60psi at turbo)
-Twin Turbo (first chrysler turbos then xspower turbos: known to not have the oil slot patent thing, but I didn't check)
-Feed from above the timing cover (stock 1/8" NPT hole in the lifter galley)
-no restrictors
-single 1/4" OD braided hose Tee'd into two.
-1/2" ID drains. One drain has a section of clear PFA tubing and there isvery little draining oil, which is barely visible when the hose steams up from heat.
-The only problem I had was a kinked rubber return line on the chyrsler tubo caused oil to leak into the turbine housing at idle (smoked like crazy). I rebuilt the whole turbo and replaced the return line and everything has been fine since then.

 

It looks like a -4 going to a 1/4" fitting that has a .035 hole drilled into the center of it.

 

wvdave, I used a valve because I couldn't figure out another way, however that has led to my frying one turbo.

How do you get a 1/4" solid fitting to drill the .035 hole in it?

 

197? block
Summit high volume pump (I think...it came with the engine)
one 1/4" steel line from above the oil filter to one T3 CHRA
one 1/4" steel line from behind the distributor to one T3 CHRA
each line has one brass restrictor at the turbo with .060" hole

No oil problems ?yet? Only about 2K miles on the turbo setup though. The T3s had unknown mileage when they went on.

I got the restrictors from www.atpturbo.com. They carry both .035" and .060" brass fittings. I have read of some people taking a regular brass fitting, drill & tapping for a brass screw and drilling the screw with the oil hole. $14 a piece seemed cheaper for me so I went with the as cast pieces. I looked around for brass fittings with a small hole but couldn't find anything decent.

I am not sure what I am going to do with the large HX/GT/TV series units. The diesel engines seem to run 1/4" ID or bigger feeds without restrictors but they always seem to have lower oil pressure (lower RPMs). Holset manuals call out a max. of 55 PSI, but no volume requirements that I can find.

 

www.atpturbo.com They have the restrictors already drilled.

 

Thanks guys.
So far that's:

Single rear feed + HV oil pump, no prob
Single side feed + restrictor, no prob
Twin front feed + HV oil pump, no prob
Single side feed + restrictor + HV, Single rear feed + restrictor + HV, no prob

TurboedTPI; Out of curiousity, do you have a larger capacity pan or is it stock? If I have to tear this thing out again I'd rather put in a HV pump this time, but I don't want it to "suck the pan dry" as people say it will with a stock pan (I just put in a brand new one). I'm thinking a 5500rpm engine might not have that problem, though. Aparently I should have done that in the first place.

For those who haven't followed my other thread, I've since installed the mentioned .060 restrictors from ATP, one on each turbo. That didn't cure the problem, but it may have prevented it initially. I want to try moving the oil feed to the side before I give up on the easy fixes. I haven't been able to work on it due to sickness and cold weather but hopefully I'll have some news to report before too long.

At the moment I would personally recommend against anyone doing it exactly how I did (twin rear feed with a stock oil pump and without restrictors) until that way is proven innocent, heh.

 

I have a stock pan. I do put 6 qts in it though. I run a heavy duty oil filter (bigger) that holds a little more oil and plus the oil in the turbo feed, turbo, and return. I figure with the engine running, it would help the "sucking the pan dry" problem. I've never had any problems, so i guess its works.

 

I was going to mention that the 0.035 fittings is for ball bearing turbos since they require less oil than a journal bearing.

 

I think it’s just dumb luck… the knock is unrelated… what does your oil pressure read? If you are reading sufficient oil pressure at the engine then the “leak” that the turbo is didn’t cause the problem.

FWIW, you want to keep the oil pressure at the turbo in the 20-55psi range… most will start blowing oil past the “seals” (oil slinger) above that unless you have a killer return/low crank case pressure/no blow by. I wouldn’t run a restrictor smaller then .060”, and for that matter, I’d try everything I could with the return and the PCV before I considered it.

I’ve heard of a decent argument for not using the oil galley plug (stealing some oil from the cam), but in real life, especially with a roller setup I doubt anyone will see an issue.

 

I run an 8 qrt pan with 1 qrt filter that came with the engine I have.

 

I was searching McMaster-Carr for a restrictor for my senior design project and found restrictors with pipe threads in like 10 different sizes for a little more than $7 each.

 

The P/N 2712T44 with a .063" hole for $7.43 is the same as the www.atpturbo.com .060" hole fitting for about $15. Love the "turbo parts" mark-up.


EDIT:
http://www.dsmtalk.com/forums/showthread.php?t=170444

 

I'm sure you can get it even cheaper than $7 from a different hardware retailer/supplier. McMaster is where you go to find what you need... then buy it somewhere else.

 

My return was a straight shot (45 degree angle, or a little steeper) of 3/4" (iirc, it has been awhile) stainless steel braided line. I never figured it would be a problem until I started the car and ended up with a huge puddle of oil in less then a minute on the ground coming from the down pipe. It literally blew the seal completely out. I am guessing the turbo saw wayyy more then 55 psi.

 

That makes/brings up 2 of my points…
- definitely no more then 55-60psi oil to the turbo… I’ve seen 65, 75… all over the net and I have no clue where people are getting this from. All of the oem/manufacturers info seems to list 55psi or so as the maximum and minimum ranges quite a bit, from 13-25psi, so when asked I tell people as long as you have between 25 and 55psi while the turbo is actually operating you’re good.
- Secondly, THERE ARE NO SEALS in most turbos. They have a groove and an oil slinger ring. In other words, they have a mechanical location that makes the oil run out so far and then get slung off by it’s own inertia to drain back in the housing, there is nothing forming a positive seal between the housing and the shaft (the only exception to this is the carbon seal used on the compressor side of the really old design draw threw turbos). To make this totally clear, if your oil drain is insufficient, oil will leak into the end housings with NO oil pressure (ask the rear mount guys what happens if they shut off their oil pump with some oil still in the housing). If there is any pressure (blow by) in your crankcase (where the oil is draining to) that means that the oil doesn’t have someplace that it can just run down into on it’s own, and you’re guaranteed that you’ll get some oil in the housings, again. Neither situation means you need a restrictor or that the turbo is needs a rebuild

 

dam fine thread guys. What I have learned is to get a nice little oil guage just at the oil feed for the turbo !

 

I've never run restrictors/orifices on my twin turbo oil feeds. The bushing clearances are tight enough that you aren't flowing a ton of oil. Currently it's tee'd off the oil inlet to the block, from the oil cooler (Dart Little M block, using front priority main oiling galley). Prior to the Dart block, I had it tee'd from the oil galley plug at the top-rear of the block, and never had oiling issues. I bet it's just a coincidence about the rod knock, unless your turbo bushing/bearings are so worn out that a ton of oil is flowing. Put an oil pressure gauge at the end of the oil galley, to see what pressure you have left after the turbos, cam, and mains get their oil.

 

Hello everyone,

I'm running the four turbos from the back of the engine oil gallery, no restrictors, no nothing. The current engine is a 100,000+ miles with no rebuilds and little to moderate blowby, but it does have a previusly used Summit high volume oil pump. The car is currently without programing so it barely starts(E6GM haltech that requires Windows 95, and I am looking for an old working laptop just for that.) When the engine starts it his under or barely 500 rpm with a very rough idle and I am having 30 to 35 psi with all four turbos getting fed, just my 2 cents.

 

off topic...but doesn't the E6GM run Win95/98 - DOS based. You can download a DOS boot disk image and save to a 3.5" floppy disk. Boot the laptop off of the A: drive and then run the Haltech program. You can do this off any machine that has a floppy drive. Actully, you can do it with a CD too but it is more complicated usually.

 

for my brother's haltech setup we use an old compaq 386 laptop and run the haltech software off of a bootable diskette

 

i read in a few books that said the pressure before the turbo at idle should be about 5psi and should peak at about 25psi while driving. i plan on running a small mechanical gauge before the turbo but after the restrictor. its going to be single turbo so i doubt it would take too much oil, but im sure i will be able to tell if there is a drop in pressure at the tee with another gauge...

 

oil pressure? that's a bit on the low side...