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Have some questions on the 4bt center dump manifold

3K views 21 replies 4 participants last post by  LiveFreeOrDietryn2B 
#1 ·
So I bought this to move my exhaust away from the fire wall what turbo feeder line length do I need and what do I need to do for the turbo drain back thanks.
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#2 ·
OK. think I can help you there. I'm assuming you plan to have the turbo top mounted and possibly an HX30W. The oil feed line in part 3909545 for the first version (part 2). The oil drain is a flex hose part 3934091 (part 7). See drawing below. That flexible tube is a bit expensive. Around $165.
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The second version is one we are more used to seeing . Uses oil feed line 3909548 (part 5), turbo drain tube 3949048 (part 7), section of plain hose 3912183 which is obsolete (part 4), and block insert 3903744 (part 3). The block insert does not have in O rings on it like the later models and it's likely a press fit into the block. There are a couple hose clamps too (part 1). Here is that diagram.
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#9 ·
It's pressed in I believe the one on the truck currently is a rear dump so the drain tube points to the back I need to either reclock it or modify it or replace it with one more inline with where the turbo will be once I mount it. I will be also porting this manifold as to help with flow and the turbo flange holes as they are 2 different sizes from the way it was cast. I'm fine with it as I'd like to reduce egts anyway. I'll be replacing the head next year with a Promaxx one and doing some hand porting on exhaust side as well as the valve guides on all of them. Please anyone trying to say the ports need to be exact are full of crap as far as saying it will hurt it. The factory casting shift makes them way off lots of pics online showing that just saying 😂 Now taking too much out can be an issue but I'm only smoothing out the exhaust ports and inside the valves smoothing things out and taking the hump off the valve guides intake & exhaust not touching ramps or intake ports.
 
#10 · (Edited)
On the oil feed hose 3909548 there's no way to know the length unless you had one to measure. You won't build that hose for any cheap price. It's a very high quality braided hose with specific fittings for the turbo and oil filter housing. Price seems to average in the $60-70 range. Here's a photo of the actual hose. One thing you should be aware of is this hose is for the vertical oil filter housing. All the ones using that center mount manifold that I've found were of that type. If you have a horizontal oil filter this hose may not fit.
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Here's a photo of a 4bt with the second style oil drain. Appears that the elbow is mounted so it points out away from the block.


On changing he clock position of that block inset piece, I'd say maybe but no guarantee. That thing is driven into that hole. You pretty much have to have it in the position you want when it is inserted. You'd need to make a tool that you could drive it out from the inside of the block.
 

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#12 ·
OK. Now, I think that is a top class secret that only the CIA might know. On both ends of the hose there are 2 adapter fittings that screw into the turbo body and oil filter housing. Those threads are M12x1.50 O ring. But you need to know the threads on the hose that screws into that little adapter if I'm understanding correctly. I used to have that info but have lost it. If you could take the hose to a hydraulic shop they could tell you. If you wanted to do a custom hose you can find an M12x1.50 to AN4 fitting that would replace the ones in the turbo and filter housing. Then you'd just need an AN4 hose with female fitting on both ends.
 
#14 ·
Caution on porting the turbo flange. That really isn't necessary and can cause more harm than good. If you want to do a porting operation that may help here's what you do. Take your exhaust manifold gasket and place it on the manifold ports. Mark the area of the ports with a fairly broad felt tip. Clean up the ports and remove the mark. Your manifold ports should now be the same size as the gasket. Now here's the secret. Go to the head and mark those ports. Port the head only leave the marks so you've got about a 1/16" smaller size in the head around the perimeter of the port vs the manifold. That miss match in the two port sizes causes an increase in gas flow velocity due to expansion going from a smaller port to a larger one. Can cause a slight improvement in boost at the turbo. Don't need to port up inside the head ports, just right at the opening. Might have a vacuum to suck the dust away when you do this to keep the dust out of the engine. I used port gas engine heads and they were a different animal. For some reason diesels don't benefit from major port work like gas engines. Could be because you aren't turning 8000 RPM. Some guys have found they may lose a small amount of power by doing it wrong so best just to leave it alone. The same with the turbo flange. Although they may look a bit ugly you don't want to overdo that.
 
#17 ·
What do the ports look like when you lay that gasket onto the turbo? If your manifold ports are larger than the ones in the turbo you've gone the wrong way. That builds back pressure and slows velocity. Those hot gases coming out of the engine expand as they go from smaller port to larger creating more velocity. One gauge that we don't see a lot of guys use but can be helpful is the exhaust back pressure gauge. Especially helpful with twin turbos.
 
#21 ·
LFOD2B: Been following your build and videos, super helpful to watch you go over all the details on your machine and getting it all into place.

Sounds like you're running the center high manifold mounted up - Could you take a measurement from the topmost of your turbo to the top of your valve cover surface?

This would help me figure if I'm going to have hood clearance. TIA.
Sam
 
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