Pat's MK4 Build Thread - Dash and Behind the Dash Wiring

[Grubester]

I will install the reservoirs soon, too, but I'm using all three because having separate reservoirs for front and rear brake master cylinders creates a redundant system if one of them fails/leaks.
At least the other one gives some useful braking. I'm I missing something here? Yes, there is the balance bar but that is a mechanical connection outside of a leaking/failing master cylinder circuit,
whether front of rear. Let me know what I'm missing. Thanks!

(can't seem to access the attachments)

[Mike.Bray]

I will install the reservoirs soon, too, but I'm using all three because having separate reservoirs for front and rear brake master cylinders creates a redundant system if one of them fails/leaks.
At least the other one gives some useful braking. I'm I missing something here? Yes, there is the balance bar but that is a mechanical connection outside of a leaking/failing master cylinder circuit,
whether front of rear. Let me know what I'm missing. Thanks!

(can't seem to access the attachments)

If one brake system fails all of the force from the brake pedal will go to the failed system. In other words, with a balance bar the force goes to the weakest side first.

Clear as mud?

[Grubester]

Actually, I have another question. How do you determine the height of the master cylinders: tops of the lids w.r.t. where the fiberglass body will be? I haven't had the body on since original delivery, and it isn't convenient now to do that. It seems there should be a dimension above or below the 3/4" square tubing that can be used as a "keep out" point. Thanks!

[Grubester]

Seems clear, but it sucks that there isn't some redundancy.

[Mike.Bray]

Seems clear, but it sucks that there isn't some redundancy.

Yep. That's why it's important not t have a MC failure!

[PMD24]

I've reposted the photos to post 120. Not sure why they disappeared, and the word "attachment" showed up.

[PMD24]

If one brake system fails all of the force from the brake pedal will go to the failed system. In other words, with a balance bar the force goes to the weakest side first.

Clear as mud?

To elaborate on Mike's post... let's say the front brakes fail and fluid is lost. Now consider that the bias bar is a lever with the pivot point in the middle. One side now has no resistance, so now when you push on the pedal, instead of the rear MC pushing fluid, it simply moves the bias bar forward instead of compressing the MC piston.

[PMD24]

Actually, I have another question. How do you determine the height of the master cylinders: tops of the lids w.r.t. where the fiberglass body will be? I haven't had the body on since original delivery, and it isn't convenient now to do that. It seems there should be a dimension above or below the 3/4" square tubing that can be used as a "keep out" point. Thanks!

I don't have my body on either but my understanding is that the body sits about 3/4" above the 3/4 tube. You mount the reservoirs as high as possible for gravity feed to the MC's, yet low enough to get the caps off. Where they are shown in my photo is temporary. I plan to raise them for bleeding, then lower them to a bit below the top of the 3/4 tube. Photos in post 120 have been reposted. For some reason they disappeared.

[Tango]

A genuine thanks for the explanation on the balance bar/dual reservoir as well as the discussion on the reservoir height in relation to the body. I have been working over some of the same concerns.

[PMD24]

Added an update to post 108 on the dash harness issue. New one received from Ron Francis.

[PMD24]

Following some discussion in a separate thread, I pulled the Tilton MCs and trimmed the pushrods by about 1/2". Since the Tilton MCs have 3AN pressure ports and the front line from the MC to the front tee will need to be altered, I ended up changing my routing and fittings. I came out of the MCs using banjos, then hard lines to bulkheads at the front of the footbox. From there I used regular flares to the front and rear. This resulted in additional joints at the bulkheads but I feel better having the AN joints and the line from the bulkhead to the rear tee is now a solid line with no joints.

rear brake line MC lr.jpg

rear brake line footbox lr.jpg

rear brake line under lr.jpg

rear brake line last lr.jpg

The vertical line on the footbox is now covered with a radiant barrier for protection from the header.

If I had to do this over I would use 100% AN fittings. Granted, you have to have the tools to do 37 degree flares, but, in my opinion, the investment is worth the many advantages of ANs discussed in other threads here in the forum.

Pat

[Mike.Bray]

Nice job! That's the way to do it.

[Justin]

Nice work, well executed!

[PMD24]

Just for the heck of it I took a shot at engine turning (jeweling) the firewall. Turned out reasonably good. The challenge when doing this on a drill press is that it is essentially impossible to apply the exact same pressure and duration on each stroke. Best results came from light pressure and a very short duration. I ended up with some jewels here and there that were slightly darker, and used Mother's polish to blend them slightly, then polished the whole surface for consistency. Jeweling material was a 1" Cratex abrasive stick. Since the drill press couldn't handle 1 " stock, I removed the chuck and arbor from the drill press and used a small lathe chuck with an arbor that matched the drill press taper. Next step will be a wipe with lacquer thinner to remove any polish residue and then apply Sharkhide to eliminate oxidation.

firewalll jewelling lr.jpg

[PMD24]

Been over a month since the last post. Not much progress since then due to other spring priorities.

But, I did receive THIS in late April. Really pleased with how it looks. Ordered late September 2024. Delivery quoted as end of December. Standard Blueprint 347 with TKX, but took 7 months to get it. I wasn't ready so it didn't matter, but multiple changes to the delivery time and only updates were when I inquired. I've had a few questions since receiving the engine and James at Blueprint has been extremely responsive.

BP1 LR.jpg

BP2 LR.jpg

Now that I have the engine I sorted out what I wanted to do with the throttle cable and ordered a Lokar cable and bracket. Primary driver behind not using the FFR supplied cable is access to the ball connector at the top of the foot pedal once the footbox is closed in. It would be nearly impossible to get to the top set screw and thread a cable into the end if I ever had to do that in the future.

Time to step up the amount of time on the build so I can get this beauty in.

[jengum]

Hi Pat. I'm getting close to ordering a BP347. Is that the engine base package with option 2 TKX transmission package? How flexible is BPE with substitutions or deletions? I noticed the QT bell housing versus the aluminum bell housing shown at the BPE website. Is the oil pan depth equal or less than 7.5"?

[PMD24]

Hi Jen - my BP order was originally option 1. When I later switched from manual to power steering, I called them and added the power steering components to the front drive. Engine was BP3473CTFK. Front drive BPP302FDE, TKX was BPPTKX600SB, and optional steel bellhousing. Other than the steel bellhousing, mine is the standard. Didn't pursue any other options or deletions. I worked with James Clark, 308-236-4181. I'm sure he can address the things you are considering.

The oil pan depth from the gasket to the bottom of the pan is 8".

Pat

[Mike.Bray]

Watch that oil pan that it doesn't hang below the frame rails. They make lousy skid plates.

[PMD24]

Thanks Mike. I'll reach out to Blueprint on that. This package is specific to FFR as part of their partnership so I'm hoping there's a positive answer.

Jen, I'll put an update on this post after I talk to them. Hopefully tomorrow.

Update 5/20/25. Response from Blueprint is... "The oil pan is a deeper sump, however, is typically flush with the bottom frame rail of the MKIV chassis. You shouldn't have any issues with the oil pan hitting while driving."

I think I will also check in with the techs at FFR to be double sure. Will update again once I do that.

6/8/25 Update: Heard back from Dan at FFR after providing him with the specific model number of the pan. He indicates that the pan may be flush with the frame but could sit slightly below depending in the final angle of the drivetrain. So, I guess I'll start by checking it once the engine is in and go from there. I'm guessing changing that pan would impact my warranty.

11/21/25 Update - engine in, pan hangs below the frame by a good 1/4". Pretty disappointing. This is Blueprint's FFR roadster engine. It's configured specific to this car and they even have a 6 page spec sheet detailing it. Yet, they supply it with an 8" pan when it's common knowledge that doesn't work. And FFR is apparently ok with that.


Pat

[PMD24]

Gas-N sidepipes have arrived. They are truly a work of art! Headers are being ceramic coated and should arrive soon.

Sidepipes LR.jpg

[PMD24]

After three months with essentially no time for work on the car I'll be back at it on a regular basis.

Gas-N headers arrived a month or so after the sidepipes, so delivery on the headers was around 8 months. Ceramic coating looks great and will help with radiant heat transfer to the footboxes. Verified that both left and right were shipped, as some have received two of the same side. Did a test fit on my Blueprint 347. All good. Access a little tight for a spark plug socket. Have ARP studs and Remflex gaskets ready to go.

headers lr.jpg

[PMD24]

Polished the engine bay side of the footbox tops and sides using Mothers, then coated with Sharkhide. Looks good and will provide an excellent barrier for radiant heat transfer. I'll also be lining the inside surfaces of the footboxes with Second Skin Damplifier sound deadening. The Damplifier will be applied so that every aluminum panel joint has an overlapping layer of Damplifier, creating complete air sealing of the footboxes. The footboxes will be under negative pressure relative to the engine bay, so controlling air leakage from the engine bay into the footboxes is really important. With an exterior radiant barrier, good air sealing, and ceramic coated headers, footbox heat should be a non-issue.

For anyone who may have an interest I shared some technical info on heat transfer in another post, https://thefactoryfiveforum.com/show...082#post576082



Footbox Exterior.jpg

Also drilled out the row of rivets where the side panel enters the tunnel and replaced them with the rivet head facing the engine bay. Purely cosmetic but glad I did it. Looks much better. You can see the tunnel rivets on the far right of the above photo that were pulled from the inside. Pretty ugly. I'll be drilling those out too. I know they probably won't be noticeable, but I can see them now, and don't like how they look.

[PMD24]

Before I installed the polished inside footbox panel for the driver side, I removed the FFR throttle cable and replaced it with a Lokar TCP-1000HT48. Impressed with the quality. I also went one foot longer than the FFR supplied length. This will improve routing for less extreme bends and reduced friction. I also like the connection method at pedal. More friendly if changes are needed in the future. Went with the Lokar XTCB-40HS2 billet cable bracket for the Sniper2. Perfect fit and will look great. I like the look much better than the stamped metal bracket from Amazon. The folks at Lokar were a pleasure to deal with as well. The billet bracket was on backorder and they agreed to ship the cable ahead of time and then cover the shipping on the bracket.

The hole above the cable penetration is the original hole through the footbox panel. The Build School instructors recommended drilling a fourth hole in the pedal arm and attaching the cable there to improve throttle feel. That in turn requires a new hole through the footbox at a lower point, so the cable aligns with the connection point. The upper hole will be plugged with a rubber plug and sealed on the inside with Damplfier.

Lokar LR.jpg


Pat

[PMD24]

Applied a small sheet metal patch at the base of the inside DS panel. Like others I ended up with a pretty significant gap there. More than I wanted to fill with caulk or rely on aluminum tape to cover/seal. I'll go over this with the same Damplifier used on all panels.

DS Footbox patch lr.jpg

Relative to application of the Damplifier, I'm not focused on making a template or using the carpet pieces to match the aluminum. I'm applying the material so that the edges are reasonably close to the perimeter of the panel and then applying an overlapping strip at all panel joints. It doesn't matter if this strip is applied before or after the panel sections are covered. The important thing is a complete air seal.

Still haven't figured out an acceptable way to seal around the smaller tubes in the footboxes. The gaps there are pretty significant. Too big for caulk. Plus, that will leave an ugly mess on the outside. Aluminum tape seems a little flimsy for the gap size. Plus, the sticky side facing the engine bay will end up covered in crud. Cutting a thin piece of aluminum to match that crescent shape would work, but then I have more rivets in an ugly pattern showing in the engine bay. Probably not too visible in that location. Any input on other solutions would be appreciated.

Pat

[PMD24]

Relative to the application of the sound deadener (or heat mat if using that), if I could do it over, during pre-fitting, I would mark the panels on the inside, for the perimeter of the Damplifier, and apply it on the bench, prior to final installation of the panel. Then, after the panel is installed, I'd apply the overlapping strips at all sheet metal joint locations. I'll take this approach on any remaining panels.

[gbranham]

Applied a small sheet metal patch at the base of the inside DS panel. Like others I ended up with a pretty significant gap there. More than I wanted to fill with caulk or rely on aluminum tape to cover/seal. I'll go over this with the same Damplifier used on all panels.

DS Footbox patch lr.jpg

Relative to application of the Damplifier, I'm not focused on making a template or using the carpet pieces to match the aluminum. I'm applying the material so that the edges are reasonably close to the perimeter of the panel and then applying an overlapping strip at all panel joints. It doesn't matter if this strip is applied before or after the panel sections are covered. The important thing is a complete air seal.

Still haven't figured out an acceptable way to seal around the smaller tubes in the footboxes. The gaps there are pretty significant. Too big for caulk. Plus, that will leave an ugly mess on the outside. Aluminum tape seems a little flimsy for the gap size. Plus, the sticky side facing the engine bay will end up covered in crud. Cutting a thin piece of aluminum to match that crescent shape would work, but then I have more rivets in an ugly pattern showing in the engine bay. Probably not too visible in that location. Any input on other solutions would be appreciated.

Pat

Butyl rope caulk works well for this. Its black, and comes in a roll. Its round and probably 1/4" in diameter. Cut a piece of appropriate length, and press it into place, then form it as needed. Not really visible from the engine bay, especially once the engine is in. I used it to seal up several spots around the firewall and trunk walls, too. Pretty good stuff.

[PMD24]

Holes cut/drilled in Firewall Forward for heater. Repeating the warning to NOT use the template in the manual. It is NOT correct. Make your own. Lined FF with Damplifier and installed. Heater mounted. Half the screws on the heater were stripped. Replaced with #10 screws. Also loosened the screws around the heater motor mount and rotated it so the wires come out the bottom. Felt that this orientation is better relative to water intrusion and preferred it for wire routing as well.

Also installed rivnuts and mounted the wiper motor.

Firewall Forward rear LR.jpg

Heater Wiper LR.jpg

Also installed fuse panel and primary wiring harness. Chose to not hinge the panel. I will extend the length of the ground wires on the flashers now in case I do elect to hinge it later. They are pretty short and wouldn't allow for the panel to swing down.

[PMD24]

3/8" Nicopp fuel lines run. Used Earls 3/8 compression x 3AN fittings on ends for transition to SS braided flex.

Final bends at the rear were based on previously sorting out filter location for future maintenance access, and routing of flex lines.

Nicop1 LR.jpg

Fuel Nicop 2 LR.jpg

Fuel Nicop 3 LR.jpg

[Waterman]

Looking good. Nice to see the project moving along. Good to see you mounted the wiper motor up higher than I did. The tubing bend to first wheelbox will be easier than mine was.

[PMD24]

Mounted fuel filter. Good access from below. Location of filter and routing of the flex lines was planned prior to running the nicopp so I didn't have any tight bends in the flex lines or strain at the fittings. Flex line clamps were fastened with pop rivets, except locations that couldn't be accessed for drilling out in the future if needed. Those few were tapped and mounted with socket head screws. Connections at the tank were left loose. Once I have the regulator installed and front flex lines made-up I'll pressure test with air, then do the final connections and tightening at both ends. That will verify the integrity of almost all of the fuel system before fuel is in the tank.

Fuel Lines rear flex LR.jpg

[PMD24]

Installed rear harness. Drilled the hole through the firewall in line with the edge of the tunnel on the driver's side instead of the location shown in the manual. The new location provided a straight shot down and into the tunnel. Had I been doing throttle linkage, this location probably wouldn't work.

Also, I recently read about a stalling issue being traced to the fuel pump connector at the tank, and some quality issues with how that connector was assembled. When I checked mine they didn't look so good. Pins weren't aligned very well and one wasn't seated and clipped into place. Seals were all messed up. 3 out of 4 were misaligned relative to the slot inside the body of the connector. What you see in the photo below is exactly how it looked out of the box.

Tank Wiring 1 LR.jpg

I removed the tape and disassembled both connectors. In the photo below you can see the tab that sticks out and locks the pin in place when slid into the connector. Inserting a small screwdriver into the bottom slot of the "P" shaped opening, depresses the tab and allows the pin to slide out.

Tank Wiring 2 LR.jpg

Inside the connector there's a rectangular opening that the seal should slide into. In my case, 3 out of 4 of the seals were not oriented to allow the seal to slid into the rectangular slot. The second photo below shows how the pin and seal should be oriented to slide in properly, engage the tab, and fully seat the seal. The last photo shows one of the reassembled connectors.

Tank Wiring 3 LR.jpg

Tank Wiring 4 LR.jpg

Tank Wiring 5 LR.jpg

If you haven't done your rear harness yet, or still have access to it, it might be a good idea to take a look at how those connectors are assembled.

[PMD24]

E-Brake Woes

I've been keeping a list of things to go back to, holding off on completing them for a variety of reasons. Decided to get a few of them off the list. One was the rear axle nuts. Assembled the ebrake handle, bracket, adjuster and clevises. Since this was a test fit and temporary use for torquing the rear axle nuts, regular nuts were used in place of the nylocs. Ran into a few issues. A couple of these issues have been documented by others, but no harm in sharing again.

The cable lugs that attach to the clevises at the handle were crimped on the cable at points that resulted in the cables being different lengths by maybe 3/8". The first time I assembled everything it was pretty clear that one cable would draw up tight while the other would still be slack. Went back over each cable and confirmed they were seated properly at the calipers on one end and the frame bracket on the other end.
ebrake cable ends lr.jpg

Decided to hook the cables to the handle and do a few pulls to see if that resulted in anything changing. But, with the adjuster unscrewed as far as I dared, it came up short by 3/4" or so from reaching the attachment point on the lever arm.
ebarake cables short lr.jpg

Using a couple pieces of scrap metal as extenders I hooked it up temporarily and ran through several cycles of on/off. No change. The DS would lock up nicely while the PS rotor could be moved by hand. You can see in the photo that one of the cables in the clevises is loose.
ebrake cables with spacer lr.jpg

I torqued the DS to 98 ft-lb + 45 degrees, then disassembled the clevis and reconnected only the PS clevis. Set the brake and torqued the PS to the same spec.

Ultimately all of this doesn't matter much since this was temporary to torque the axle nuts. Like many others, I don't like the cables running under the frame, so I'll be adding the pulleys, cutting off the cable lugs, and using the Lokar cable block to even up the lengths. More on that in a future post.

I also have the issue that others have reported where the end of the front bolt that holds the handle to the arms, doesn't clear the aluminum panel. I confirmed that the mounts to the frame were over on one end and under on the other and shifted the positioning in the mounting slots to the position providing the most clearance. The bolt still contacts the aluminum.
ebrake handle bolts rubbing lr.jpg

I'll be removing the handle/lever assembly for painting, so when I reassemble it, I'll place the head on the inside, the nut on the outside, use a 1/4" shorter button head screw, and a low profile nyloc nut. Putting the head on the inside should give me acceptable clearance.

[gbranham]

Just bend the ebrake bracket on the frame a bit to clear the aluminum.

[PMD24]

Just bend the ebrake bracket on the frame a bit to clear the aluminum.

Thanks. Will give that a try while it's still installed temporarily.

[PMD24]

Converter Wiring

Opened up the rear loom to check out the wiring for potentially tying in the converter there and ultimately decided to do it at the dash. I can make the converter reasonably accessible for replacement if needed in the future. The front location will leave me two purple wires running from the dash to the rear of the car. I can make use of both; one for the reverse lights, and one for trunk lighting.

Any input on my approach on tying in the converter would be appreciated.

My plan is as follows:
> On the main chassis harness I will cut the black ground wire leading into the black connector for the rear harness, and splice in the converter, black chassis to white converter in, and converter white out to the other side of the cut black chassis wire.
> On the main chassis harness I will cut the tan taillight wire leading into the white connector for the rear harness, and splice in the converter, tan chassis to tan converter in, and converter tan out to the other side of the cut tan chassis wire.
> On the main chassis harness I will cut the yellow left turn wire leading into the white connector for the rear harness, and splice in the converter, yellow chassis to yellow converter in, and converter yellow out to the other side of the cut yellow chassis wire.
> On the main chassis harness I will cut both of the purple brake light wires leading into the black connector for the rear harness. The two purple wire cut stubs at the black connector will be removed by removing the pin from the connector. The two purple wires coming from the main chassis harness will be traced to determine which one comes from the brake switch, and which one comes from the Hot Rod column connector. The one purple wire coming from the switch will be connected to the red converter in. (Note that there is no converter out associated with this.) The other purple wire that goes to the flat Hot Rod column connector will be removed.
> On the main chassis harness I will cut the white right turn wire leading into the white connector for the rear harness, and splice in the converter, white chassis to green converter in, and converter green out to the other side of the cut white chassis wire.
> All connections will be made with crimp butt connectors and sealed with heat shrink tubing.

On the dash end of the rear harness the black male connector has two purple wires that lead to the DS and PS taillight looms. These wires will be cut of at the connector, and the pin will be removed. These two wires are unused and can be utilized for other things, such as the reverse lights and trunk lighting.

[gbranham]

Trailer Adapter.jpg

[PMD24]

Trailer Adapter.jpg

Thanks. I used that schematic to do mine. FFR manual is pretty skinny on detail.

[PMD24]

PS Rear Tab Removal

Cut the tab off the frame at the PS rear above the tank strap mount using a cutting disc, then ground it down a bit, leaving enough material to maintain the integrity of the weld. Applied some paint. Carpet will ultimately hide it all.

PS rear tab removed lr.jpg

[PMD24]

Final E-Brake Install Complete

Removed the temporary ebrake setup detailed in post 152, disassembled and painted all bare metal parts. Removed handle screws and reversed them so the heads are on the inside, which provides more clearance at the sheet metal. Reinstalled handle assembly. I then drilled/filed out the end of one of the clevises to accept a 1/4" bolt.
ebrake clevis drilled lr.jpg

And filed the radii on the inside so a nut would sit flat inside the clevis.
ebrake clevis filed lr.jpg

The clevis was then attached to a Lokar WCA8070 Connector Block with a 4" bolt. The nut inside the clevis is captured and does not turn. A locking nut is on the outside of the clevis. The Connector Block is threaded but I did not use it that way. The 4" bolt simply passes through the block.
ebrake clevis adjuster assembly lr.jpg


Ebrake cables were then cut with a 3" cutoff wheel and sheathing removed. Cables were inserted into the block and secured with the 4 allenhead screws with blue Loctite. In this photo you can also see that I did not use the carriage bolt on the rear L-bracket. Replaced it with a button head cap screw with the head on the bottom. I did this because the clevis/adjuster assembly was contacting the nut and screw threads when the carriage bolt was used. I don't love the angle at which the cables come out of the pulleys, but this is about as good as it gets to avoid going under the frame. Ebrake install complete and functioning well.
ebrake installed lr.jpg

[Dondero14]

Hi Pat,

Great job on your build so far. I just stumbled upon your build thread today and it has had some great information for myself to look into and prepare for as I get to that point of the build. I started my build last month and have a very similar setup so I'll definitely be following along to better prepare myself for the bumps along the way. All the pictures you've posted and great attention to detail is much appreciated from a readers perspective. Funny how some of the issues I've ran into you have address and brought up in this thread, which I wish I had followed along earlier in the past. Needless to say I've enjoyed learning from your build and look forward to following your thread.

Mark