'85 Merkur XR4Ti Rally Car

I wouldn't think so. I might look at the fuel pump. Maybe it's not flowing enough to build pressure against the regulator?

Sorry to hear Speed Equipment dropped the ball on the driveshaft. I haven't used them in awhile. Maybe things have changed.

In reply to Ian F:

They did say they were swamped when I dropped it off, things looked busy and they probably don't need the extra work of doing some weird one-off modification.

Fuel pump is the next thing I plan to try, although the one in it was just fine a couple months ago with the stock lines. I may try adding some sort of restrictor to the return line just to see if it helps since that should be easy to do.

Looking good!

So it was the fuel pump- sort of. Not the one that was installed, but part of a previous one- the formerly crimped on metal portion of another fuel pump was lodged in the soft line in the tank:

The metal thing on the right, which matches the one on the end of the fuel pump on the left, was wedged in the line sideways- I noticed it when I was looking for cracks in the rubber, and I'm pretty sure it has been there for a long time but waited until now to turn sideways and start restricting the flow. Dug it out with a screwdriver and put in the fuel pump from the parts car- fuel pressure is now happy, although I still have the wastegate opening at 10psi so I'll have to be careful when I crank up the boost again to be sure that I solved the whole problem.

We're now a slippy clutch and a couple of oil leaks away from 100%

Good to hear. I hate it when it's something dumb that causes an issue!

Also, if your race car isn't leaking some oil, that just means it's out of oil!

Took the car for a spin after work- by the end of the drive the clutch stopped slipping! Boost is still set at 10psi, which is pretty slow on this thing, but I think I'll keep it there until I'm certain the clutch is as grippy as it can get.

I'm a little sad we don't have snow tires for it, since tomorrow is snowpocalypse '17- then again, it means I won't have to dig out the garage so maybe I'll call it a win

Drove the car for an hour after work yesterday, it runs well now but the clutch is weird- it slipped at the beginning of the drive, then seemed to "warm up" and held after 10 minutes or so. Then I hooked the boost controller back up to get 18 psi again- it slips there, but it was a nice reminder of how much power the car is supposed to have.

I don't think I'll be attending the DC RallyX this coming weekend, it's too far to go with a car that may E36 M3 out the clutch after a couple of runs, and I'm getting really nervous about the RV trip so I want to work on that thing. Maybe I'll get out to a Susquehanna region RallyX since that would only burn a day instead of a whole weekend, but for now this car is second priority.

Great to see the renewed life this car has received. When Matt dropped the price on it, I was surely tempted. Thanks for posting all the updates... I'll be following.

In reply to darkbuddha:

Good to know people are watching!

Unfortunately, it looks like the new clutch is just not going to be happy- I think in my conversations with Spec, the fact that I only had a T9 pressure plate was lost, and I probably needed a T5 pressure plate instead. The parts car has a perfectly good clutch, but to move that over I'll need to drop the transmissions on both cars. Right now, with the big RV trip approaching, that's not happening- so this car will probably just be parked for the next month and a half

I yanked the trans and clutch out of the parts car last night, because it was driving me nuts that I haven't touched either of the Merkurs in a month. Now I just have to do it again on the rally car, and maybe try to pinpoint some more oil leaks while I'm in there.

Let's get caught up- trans out:

Clutch off, flywheel off, found the problem; the 6 puck Spec clutch disc has a slightly different swept area than the standard type disc, so not having the flywheel resurfaced is what bit me- the disc was riding on a ridge in the flywheel surface instead of making full contact. The parts car had a nicer flywheel (below on the right) with ARP hardware, so I used that along with the clutch setup that it was mated to:

Bolted up:

I took some time to hammer the tunnel a bit for more clearance- Ford inexplicably made two versions of the XR4Ti trans tunnel, the parts car has the wide tunnel which is much easier to work with but the rally car is the narrow version. Installation is reverse of removal, just with more swearing, because here at Ford we think tool clearance is something that happens at Sears on Black Friday, not something we have to design for:

It fired up just fine after two months of inactivity, and I went for a drive:

The clutch problem is fixed! It grabs nicely and lets me spin the wheels with ease... but the fuel pressure problem returned

Much parts swapping ensued, and eventually I determined that 2 out of my 3 Walbro pumps are bad and only make 32 psi of fuel pressure- but the 3rd one I tried works great and the car is fast yet again. It's nice that the failure mode on these pumps seems to be lowered pressure rather than just outright dying- assuming I catch it before I melt the pistons or something, I could just wedge the wastegate open if it happened during a rally and still be moving, just a lot slower.

I think we've had this discussion before, but those a T-5s right? If you happen across a T-9 looking for a home, give me a shout.

I have a T9 with a short shifter, it worked well when I took it out- do you want it?

Yes!

PM sent!

While everyone is having fun at STPR, I'm still here working because I have no vacation left after the RV trip!

I finally made Chief fully legal- technically the red lights and fire department decals could have gotten me in trouble, so the red lights got black plastidip, the white strobes got yellow tint, and the decals got removed. This was my first time using an eraser wheel, and I have to say it was $9 well spent- it took off 20 year old decals easily and left the paint looking better than before:

I also finally made a new lightbar for the rally car- I wasn't a fan of the halogens or the way they were mounted, so I made a rack out of some angle iron which mounts to two of the holes from the old bar, and two spot under the hood. The top mounts are low enough profile to close the hood over, and it's pretty beefy and doesn't shake at all:

The lower bar is the curved one that Brian gave us, and the two upper ones are supposedly ultra long range units- I've found that most LEDs throw a buttload of light but struggle to throw it far enough, so hopefully they do the trick. I have room to add more if needed, but I like that this arrangement doesn't obstruct the grille at all. It certainly seems bright in the garage:

Another test drive, another dead fuel pump

I think the strainer is too close to the bottom of the tank- internet says Walbros are sensitive to inlet restrictions. Anyone have any thoughts?

In other news, the lights are great!

Got a new fuel pump installed, went for a drive, and promptly blew up the PS CV joint- I guess it makes full power again!

At least it went now not on stage!

Yep, I'm pretty happy that all this stuff seems to be happening when I have time to fix it!

As it turns out, the axles are fine- the hardware, however, not so much:

These appear to have backed partway out and sheared off- they have no grade markings on them, and I had a box of identically sized grade 12.9 socket head cap screws, so all 24 axle fasteners got replaced with high strength stuff and Loctite'd.

Then I went for another drive and couldn't make full boost- that intake junction I sealed with RTV apparently would prefer a gasket, since it's leaking again:

I also replaced the dead passenger window motor with the one from the parts car, which was no fun at all since Ford decided to tuck all the fasteners in between razor sharp pieces of metal, which you have to access completely blind.

Some aero work also happened:

If I called this big piece of plastic a Gurney flap Dan Gurney would rip it off the car and beat me to death with it, so let's call it a ducktail instead- its' purpose is twofold, it both holds the cracking plastic lower wing together and hopefully makes it a little more functional at lower speeds.

Awesome! It looks like a car again

I like the duck tail.

If you want to call it a Gurney flap go ahead. I'm pretty sure if Dan has a problem with it, I could take him.

Unbolted upper intake manifold... what in the flaming E36 M3 berkeley?

It wasn't leaking because of the RTV... it was leaking because it somehow cracked itself through, while bolted to the car. I cleaned the crack, slathered a large amount of JB weld in there, and reassembled the thing with a gasket so the cracked part can cure under clamping pressure. Hopefully that works, if it doesn't then I'll have to take it out and bring it to somebody who can TIG weld.

Is that a cast aluminum intake? If it is, your up a creek as it's damn near impossible to weld cast aluminum

It's cast aluminum, and it looks to have been previously cut, rotated, and welded back together (a common mod for these)- which is probably a big part of why it failed. The parts car has a custom fabbed upper intake manifold, but it lacks some of the bracketry needed to work on the rally car... we shall see. I'd like to keep this one functioning for now since the plan is eventually to yank the entire engine and megasquirt setup from the parts car and put it in the rally car; moving single pieces over seems like a little bit of a waste.