'85 Merkur XR4Ti Rally Car

BrokenYugo wrote: On the welder penetration, assuming a 120 volt model, I'd guess insufficient wiring. The 120 volt models should have a little analog panel meter on them to monitor the voltage, red zone below 115.

The odd thing is, I'm running on the same circuit that I used to do the cage feet in the RX7, where I had no penetration problems. I wonder if running the air conditioning in the house had an effect, as that's the only obvious difference between then and now- or maybe my welder is taking a dump.

Cant wait to see this thing flying on stage!

Love these cars!

Replaced the MC+booster with the combo the seller told me should improve things- after I got everything together I went to bleed it and discovered that the "better" master cylinder is plugged with rust

I ordered a new one, it's not like I don't have stuff to do while it ships.

Bummer deal, at least it's progress!

True. Hopefully we'll get a lot of it knocked out this weekend, the goal is to have the car on the road again in 2-3 weeks so that we have a solid month to test it before Black River.

Welded diff installed:

The turbo fought me more than I thought it was going to, but it's finally in. To put a T3 with a Cosworth turbine housing in one of these cars, you (apparently) have to:
-Drill out the holes in the turbine flange to 10mm or larger (they're too small stock)
-Make or modify a wastegate actuator bracket so that it doesn't get in a fight with the oil drain line
-Cut down the lower rear stud on the exhaust manifold so that it doesn't hit the turbine

It would have been a lot quicker if I had known these things instead of repeatedly installing the turbo and finding them out as I went along, or had drill bits that weren't made of pure Harbor Freight Chineseum carbide, but oh well- everything I found online seemed to say it just bolts up.

The offending stud:

I'm also going to need to figure out a new way to connect the AFM to the compressor inlet, this car came with two versions of that hose, both of which are held together with duct tape. The AFM is 3" and the compressor inlet is like 2.75" or so, and it needs to bend... this may be one of those "walk around the parts store holding the parts in question and taking things out of boxes until they kick you out" type solutions.

Tomorrow I hope to tackle the boring water pump/thermostat/timing belt job and get started on the exhaust.

Working on the car but taking a break for a PSA:

That non-threatening tiny wire wheel you're using to clean the old gasket off your thermostat housing is more than happy to grab the velcro strap on your work glove and winch its' way right into your wrist, which it will then abrade at a surprising rate.

PSA number two:

Just because you have it chucked in a drill does not mean that reversing said wire wheel at full speed will fix the above situation.

¯\_(ツ)_/¯ wrote: The odd thing is, I'm running on the same circuit that I used to do the cage feet in the RX7, where I had no penetration problems. I wonder if running the air conditioning in the house had an effect, as that's the only obvious difference between then and now- or maybe my welder is taking a dump.

Knowing where you live, I'd say voltage drop could be the culprit. Your A/C plus every other house on the medium voltage line also running their A/C could drag down the system a bit before it even reaches the transformer that feeds your house. The utility lines in more rural areas tend to be "minimal" at best, to "undersized" at worst. Utility companies often have no qualms about installing the bare minimum to a system and then upgrading only if/when it blows up.

I've always had an interest in the XR4Ti. There's an ex-US Top Gear car on BaT right now. I'm curious to see what it sells for. While I need another project car like a bloody hole in the head, it's tempting if it sells for a decent price (any thoughts on value?). You know... one way the teams help to offset the per-event costs is to run multiple cars... ...and for better or worse, the DH racing bug is starting to fade faster than I expected it to...

I don't really know what non-rally Merkurs go for, but I'm guessing that car will go for $5k+, which is a lot more than I'd pay for a stock one. If you want one I'd say these (found by Josh) are a better bet: CL link

While those do look like a good buy, anything that is not running and needs a trailer is out for now. I'm kinda surprised you aren't consider them for parts cars? I'm looking more for a reasonably decent, but slightly ratty "runner" to use for auto-x, rally-x, track-days and eventually to cage and do rally with. In reality, there's a good chance I'd actually end up navigating and having an old DH racing buddy be the driver if I do build it for stage rally.

Anyway, we'll see what the TG car sells for...

¯\_(ツ)_/¯ wrote: I mangled one of the water lines when I took it off. I have heard that the water cooling is not that important for a turbo on a race car, anyone have any thoughts on that?

Just idle the car for a few minutes before shut off. Water cooling helps prevent the oil from coking inside a hot turbo.

¯\_(ツ)_/¯ wrote: I don't really know what non-rally Merkurs go for, but I'm guessing that car will go for $5k+, which is a lot more than I'd pay for a stock one. If you want one I'd say these (found by Josh) are a better bet: CL link

I've liked these cars since before I had a license. Those two on CL like 10 minutes from me are so tempting, if I only had a place to actually put them...

In reply to Ian F:

The main reason I'm not considering those is that the budget is somewhat tapped out right now- if someone buys the Aprilia I'm selling then I'll be looking.

Timing belt, water pump, thermostat done:

The new thermostat is a 185 degree piece vs the old 195 degree, the hope being that I can start each stage with a lower temperature for a little more buffer. I don't have the rest of the timing cover, and although it has run multiple rallies like this I kind of want to keep stuff out of the timing belt- maybe a junkyard trip is in order.

Then I got the downpipe tacked together:

I ended up hammering the firewall back a bit for clearance- when the answer is either "make a more complicated part" or "attack the car with a hammer" I always decide it's hammer time. Amusingly, sand imported directly from the last rally poured out of one of the holes in the fenderwell when I did this- it went a long way and waited a long time to make my garage dirty.

For any of your XR needs, get a hold of Jeff at MPM. If he doesn't have it, he knows who does.

He'll have a timing cover for ya.

http://merkurmidwest.com/

In reply to GPz11:

If there isn't a readily available 2.3 to pull one off of in the junkyard I'll definitely be giving him a call. Since you seem to be the resident Merkur guy, where should I be setting the boost with my current arrangement? .60 A/R compressor, .48 A/R Turbine, Large VAM and injectors/ECU to match, small intercooler, Saab radiator, RX7 oil cooler (hopefully), 3" exhaust, 93 octane pump gas, Walbro 255 fuel pump. Is 18 psi a safe number?

What Tire pressure? Just make it match. Easier to remember that way.

In reply to Dusterbd13:

Pretty sure running your tires at 90 psi is bad.

Yup, 18 should be just fine. Do you have a wideband in the car?

In reply to GPz11:

Nope. If that means it needs to come down a couple psi I'm OK with that, the primary goal is reliability but it seems like a waste to run really low pressure when it has all of this fancy stuff on it.

You should be just fine at 18. A wideband is just a good thing to have. You might also consider a fuel pressure gauge.

Both are just good to have.

I second the wideband, for the cost its almost an essential part

Continued working on the exhaust tonight. The downpipe is tacked together, I'm going to have a friend TIG it since it's stainless. I got started on the back portion of the exhaust and discovered something is definitely wrong with my welder or the wiring to the garage:

Things started off OK, but by the 4th weld joint on this piece I was running at max current, 30% wire feed, and popping the breaker to the garage every 30 seconds just to barely stick the tubing together. I'm not done, so this exhaust may have to get finished using the Harbor Freight flux core piece of E36 M3... because at least it works.

Multimeter shows 120 volts to the outlet I've been using, not sure if there are any better outlets I can run an extension cord to. When the welder is running on maximum current, the voltage to the outlet only drops to 118-119v. So I'm thinking Eastwood is the shiny happy person here.

How long have you had it? I'd give them a call since you're reasonably local to the store and I get the impression they generally stand behind their products.