Underdiscussed engine swap questions: accessories and clutch pedals

I've been reading engine swap build threads for years. For some reason two topics don't seem to get the kind of attention that swap wannabes like me need to learn about. I'm looking for info on Power Steering and clutch master choices.

Swapping in an engine from a different manufacturer, how do I decide what to do with the power steering?

Keep the chassis's pump and adapt to the engine

Keep the engine's pump and adapt to the chassis

Swap in an EPS column

Swap in an EPS pump

Swapping a manual transmission into an automatic car. How do I figure out what master cylinder bore and pedal length that I need? Due to space constraints in my giant sedan I'll need an interior master cylinder so I can't just take the pedal/master from the trans donor vehicle. I'll pick a trans that I want and use it's factory slave if possible. Then how do I know what size clutch pedal/master to attach to it? I wouldn't mind finding a factory manual pedal set for my car but they're super rare in the US and what's the chance that those hydraulics would work correctly with whatever transmission I end up with?

Is there a reason you are being cagey about the specific car you are swapping? 

The answer to all of your questions is: You do what is easiest sticking to the OEM method, or what you have to do, or what you want to do. In that order. Nothing you dream up will ever be as good as the OEM solution, so best to stay with that when possible. If not the OEM solution, at least use OEM parts when designing a solution.

Clutch linkage is not difficult, but it is kinda a PITA due to where you have to work, I loath internal throwout bearings, but if you gotta you gotta. Once again, Miata is the answer as it's pedal assembly and master has fit into about 4 swaps that I have been involved with. As for stroke, bolt all your parts together, bleed the system and see if you have enough stroke. If you do not, go one size up on the master bore or one size down on the slave (external only) .

Im assuming this is benz diesel. 

When we built the amc, it was with a ford pump and jeep steering box. We did a double flair union on the pressure hardlines so it was jeep on one end of the pipe and ford on the other. 

Keeping to the OEM method is the simplest, but using your discretion is okay as well. They are in that order. It is always better to stick with the OEM solution when possible, as nothing you can think of will ever be as good as it. Choosing an OEM solution is not always necessary, but using OEM parts is.

What about the donor vehicle? Im assuming that theres no factory pedals for the recipient,  but the manufacturer already figured out the harsmd stuff for the donor. 

Mounting PS pumps and doing it well is hard, use the pump designed for the engine. You may have to play with restrictors or springs to bring the pressure into the right range. 

Pedal, work backwards. Find out what you can about the pedal ratio and master size for the donor, and adjust one or both of those in the swapped car to match. It's a lot easier to math this out than swap out a bunch of parts, but you may end up trading off some more throw for a lighter pedal if that's what you want. 

GRM's writer Carl H (and his miata into mgb swap stories) go through the math on the clutch pedal work in pretty good detail. But it's just ratios. x/y = a/b, and you have to do it a few times. Pedal distance to pivot, pivot to pushrod, pedal travel, pushrod travel, pushrod travel and master bore to slave bore and slave travel. 

OEM+ is always my choice. Grab as many factory parts so later repair/replacement/sourcing is easiest. Math is definitely the 'measure twice, cut once solution' proper solution but I always end up just installing what I have and then modifying to suit.

Go with the engines native PS pump setup unless the chassis can't hold it and then I'd look at EPS column if I can get a nonpowered rack/gearbox or remote EPS pump if I can't.

NOHOME said:

Is there a reason you are being cagey about the specific car you are swapping?

Sorry, no secrecy here. Engine is a 2004 VW BHW and car is a 1979 Mercedes W116. 

I haven't pulled the new engine yet as I just got it home and still haven't made a spot for it in the shop yet. I left the power steering pump and lines connected in the Mercedes. Is it just as easy as going to my local hydraulic shop and having them make me lines with the pump threading on one end and the box threading on the other? I've not dealt with PS stuff before so I don't even know what kind of lines or fittings are used.

I wish I could just take the pedal/master from the trans donor. But the location on my firewall puts the brake booster smack in the way or if I push the master outboard it would put the master inside the fender. Deciding on a trans is kinda tough at the moment. I would rather not have to make a remote shifter so I've got to find the appropriate shift tower location on one of the possible donors. That will be a challenge in itself. There also don't seem to be too many options for aftermarket clutch pedals with the master inside the car. It's amazing how little space there is in a luxury sedan.

One trans I really like and looks to have about the right shifter location is the T5 found in S197 4.0 mustangs. But it uses a hydraulic TOB which I don't particularly care for. After I get the engine mocked into place I'll know for sure. 

A really smart guy always suggested using the parts from either the chassis donor or the driveline donor.  Failing that, keep it to one of the two manufacturers.

Example above - 

VW engine, Mercedes Body.

Clutch and PS stuff should be from either of the two vehicles, so either a VW clutch linkage or a Mercedes linkage.  Same with the PS pump.

I like to keep accessories and engines from the same manufacturer/engine family.  As stated above there is a ton of design work into modern accessory drive, its a whole lot easier to adapt wiring or oil fittings and lines than make brackets and whatnot that will be reliable, quiet, and lined up right.  

So this would be  representative of the recipient engine bay?

If so, what is the box where the clutch master would reside and how hard to relocate?

What does the under-dash real estate look like?  Can you put the clutch master inside behind the pedal?

Was there a manual version made anywhere in the planet?

Power steering wise, I used one of the Volvo remote electric pumps with AN conversion fittings and it worked quite well. Easy to install and wire. Cheap to buy. 

If I could figure an elegant way to modulate it, I would tap off the EPS pump and use it to actuate the clutch; maybe steal some tech from the electric gas pedal world and apply it to the problem. Sounds like an Arduino project.

That black box is the fuse box and the wiring harness passes through behind it. Underdash real estate isn't terrible, I just need to figure out what a few relays do and see if I want to keep them. There is a manual pedal set available in the US but very rare. In true MB fashion it places the master inside the car behind the pedal The R107 and W116 cars share pedals. I love the packaging but I hesitate because I'd then be stuck with the master size from MB.

Looks like Mercedes already figured out your engineering.  I would definitely get the manual trans pedal set.  Even if its real money the integration will be worth it.  

 Looks like there is adequate room to modify the bracket if needed, you can also get a different clutch slave or master from Wilwood or Tilton

I was thinking something like this. Tilton makes one or make your own.

Or maybe a floor mount?

Or think out of the box and figure how to operate a cylinder with a cable. It just has to pull rather than push.

If you check, I bet the MB clutch master size is 3/4 (or 19mm if you prefer). I know it is for a W123 anyway. I also second finding a factory pedal setup no mater how much ebay scrounging you may have to do! Life will be so much easier that way. I used a 3/4 bore push slave from a mid 70's Toyota Land Cruiser, when I put 302 and T5 in my W123. It was cheap and I think it works pretty good, though an internal thowout bearing slave would have been a better choice given how close the slave ended up being to the exhaust.

As for P.S., use the pump and brackets that go to your donor engine, though you will most likely have to change the pressure relief valve and spring to get the steering feel right. The pressures for a rack are different than what a recirculating ball box needs. For the hoses, a good hydraulic shop can adapt fittings and crimp new hoses for what ever you need.

Something you didn't mention, but I'll throw in here is for the rear diff joint on the Benz. Jags That Run sells an aluminum adapter that allows you to use a bolt on yoke, standard u-joints and driveshaft to go with your slip joint on the T5.