RustlesRoadster

[Jeff Kleiner]

I actually prefer and recommend 255/40 for the front rather than 245/45. I've used that size on my car as well as on roadsters I have built for others. No personal experience with the 888; I've run mine on Sumis, 2 sets of Kumho XS and currently with Nitto NT-01. What are your plans for the rear?

Jeff

[russelljones48]

Jeff,

I was looking at 315's but I'm not sure they will fit either - having trouble finding a good selection of 17's for the rear. FFR is running 18" on their Coyote 305's in back. They are 12W X 26.5H and the 888's only come in the 315 or a 275. Would like the wider tire. I'm now checking for other brands.

Russell

[Jeff Kleiner]

315/35-17 fit the rear when mounted on the FFR 10.5" wheel...got 3 of 'em sitting in the garage right now.

Jeff

[russelljones48]

315/35-17 fit the rear when mounted on the FFR 10.5" wheel...got 3 of 'em sitting in the garage right now.

Jeff

Jeff,

Thank you - that solves the conundrum. Since these tires are likely to last a long time I didn't want to make a mistake.

Russell

[russelljones48]

Jeff,

BTW - your body and paint thread has convinced me to do my own paint job. It's been 35 years since I painted a car so I was afraid the technology had passed me by. However, I will do the car in white (single stage) so it can be final sanded and buffed.

rj

[russelljones48]

OH found this site with a pretty cool tire size comparison tool. There are probably others out there but this one worked for me. FYI not all tires of the same size are actually identical - manufacturers can differ so use this or any other tool as a guideline.

http://www.rimsntires.com/specspro.jsp

[russelljones48]

Ordered tires yesterday - Jeff thanks for recommendations. AND...... After all this time and effort, with the rear brackets removed the pumpkin slipped in in 2 minutes.... The new rear mount is still not complete but should be shortly. FFR shipped me 2 new brackets that should arrive today. Then there's just a couple of cuts and welds and I should be done - YEAH!!! FFR IRS Pumpkin in place 1.jpg there's gotta be an easier way to post pics that what I had to go through....

[russelljones48]

OK, bracket is now welded up and fits like a glove. Thanks to Mike N. for both the advice to set it up with about 1/16" more side clearance and for welding up the bracket for me. Thanks also to mikeinatlanta for the basic design idea. I posted some drawings with dimensions on the FFCars site and here is a picture of the welded up bracket. I will drill the bolt holes, media blast it and take it to the powder coater today. Still need to weld in the rear brace for it but I'm happy that this chapter is almost over. I'm also (actually we're) making good progress on the mount for the AP Racing front brakes. Prototype should be ready when I return from my trip.FFR Pumpkin rear bracket.jpg

[russelljones48]

OK, so my next challenge is rear brakes and, as usual, my research leaves me a bit confused. I have the IRS knuckles from a '98 Lincoln. I assume they are the same as the IRS Cobra but need confirmation. My other question is this - what Ford brakes (rotors, calipers, and mounting brackets) will fit. Ford has discontinued most of these parts so I will need to go to the aftermarket for components. In looking for rebuilt components the only sure thing looks like the '98 Lincoln, but I'd prefer to get a larger rotor and "better" caliper on the car. Guidance would be greatly appreciated. It also seems that most of the components I'm looking for are the same for the live axle and the IRS but again I'm not sure.... I do understand that various performance Mustangs from 2001 - 2004 had slightly different rear brake set ups so it would be nice to know if those could be adapted to my car as well.

rj

[CraigS]

Pretty sure Forte has a Wilwood rear caliper setup for the IRS. He did 2 years ago for sure. BTW, you will love the 888s. One of the faster autocrossers in the DC area used them for his street tires and swapped to A6s at the event. BUT, on colder days at the beginning and end of the season he would run on the 888s. He was convinced they were faster in those conditions than the A6s.

[russelljones48]

Yes, I think he does but I was hoping to keep costs down by going to FORD pieces. Ans I can't wait to get it rolling on the 888's - thanks

[russelljones48]

After several weeks of travel, kids, grandkids and some minor surgery, I'm back at it. And, it seems, as usual, stuck. I'm trying to get the steering rack installed with the Breeze bushings, and get it centered but things aren't working according to the various directions and descriptions that are out there (Youtube FFR, mk4build.com, build manual, Breeze etc.). Recap: Mark IV chassis delivered 2/2015, manual steering rack delivered 4/2015 - so the rack appears to have the long inner tie rod ends.

Here's what I've concluded and I'd like advice and confirmation:

1.) Unless I grind out the mounting holes about 1/2" even with the Breeze bushings the rack won't center and if it does the bushing position will not be optimal from a height perspective - i.e the rack will not be in the lowest possible position.

2.) Keeping the rack in the lowest position will reduce bump steer the most and is therefore what I should try to achieve.

3.) The inner TR extensions are quite long and if I shorten them unequally to compensate for the rack being off-center then centering the rack in the chassis doesn't matter.

In summary, my plan is to keep the rack as low as possible putting the Breeze bushings with the bolt hole at 12 noon. Measure and cut the inner TR extensions to different lengths to compensate for the rack being about 1/2" off-center. So, the passenger side TR extension will end up about 1/2" shorter than the driver side. All this making sure that I have enough adjustment thread to get the car aligned properly.

I suspect there are some flies in this ointment, so please have at it :-)

[Mike N]

Russell..

When all assembled the length of the inner tie rods (inner joint to outer joint) should be the same on both sides other wise you will have different steering (bump steer) geometry on each side which will make for some potentially weird handling characteristics. The fact that the rack housing is not centered is not critical but might lead to having different number of turns to lock left and right. I'll stop by later and check out what you've got.

[russelljones48]

Thanks Mike!! So, there was a fly in the ointment. My theory was basically correct BUT. Mike stopped by, we pulled the boots off and I now understand how to set the rack up so the inner tie rod end pivot points are located at the same point on either side.... And at Mike's suggestion I also ordered a bump steer kit - couldn't find one on the Breeze site so it's a Steeda.

[Joee]

Make sure the bump steer kit you get doesn't require drilling your spindles. Forte sells a kit that fits right in.

[Mike N]

Joe. That's why I pointed Russell to STEEDA. I got mine from Mark at Breeze but he doesn't carry them on his website anymore. I wasn't aware that Fortes has them.

[CraigS]

W/ MkIV spindles the steering arm is a separate piece so drilling out the tapered hole is not the problem it is on the Ford spindles.

[russelljones48]

I've got a call into Breeze (and a text to Mike) but it looks like I will have to "slot" the mounting holes on the passenger side to the outside to get the rack so the pivot points for the inner tie rod ends "match" on either side. I'm somewhat concerned that the rack could then move around because all 4 mounting holes are now slotted. I could "pin" the rack in when it's all set but wondered 2 things: has anyone else had to slot the PS mounting holes and did they do anything (like pinning) to keep the rack in position? Breeze's instructions do mention that enlarging/slotting the mounting holes could be required.

rj

[Mike N]

How much 'off' is it? I wouldn't sweat the housing being perfectly centered.

[CraigS]

I agree w/ Mike. I have never needed to slot the frame hole in the 4-5 cars I have worked w/ the rack on. W/ the offset bushings you should be able to get at least 3/8 inch of lateral movement and only have maybe 3/32 inch of vertical movement.

[Jeff Kleiner]

I agree with Mike and Craig. I've not had issues with rack centering on any of them I've built. RE: differing lock to lock left to right---generally tire contact with the F panels are the limiting factor, not the mechanical travel of the rack. Why the bump steer kit? You're not far enough along to be able to measure to determine whether you even need it (if you're using FFR spindles you won't).

Jeff

[russelljones48]

So I kind of have 2 questions. The first one being will the rack potentially move around if I have "slots" on both the passenger and driver side. I think the answer is no as long as it's torqued to about 60-65 pounds. Now for the "centering" question.
Here's how I'm determining what I think is the optimal rack position. With the steering turned all of the way to the drivers side I am measuring the exact distance from the outside of tubular frame to the pivot point on the inner tie rod end. For argument's sake let's say that distance is 1.5". I then rotate the steering shaft to opposite stop on the passenger side (i.e. the maximum right travel and measure that same distance from the passenger side frame rail to the inner tie rod pivot point. Let's say that distance is 1". I then move the rack 1/2" to the passenger side (in the slots and with the Breeze bushings). Once that is complete both of the inner tie rod end pivot points will be 1.25" from the frame at stop on either side at maximum travel. This should insure that the steering geometry/bump steer is equal on either side when the car is going straight down the road. I did not try to center the steering and then make them equal because using the "find the center of the rack by rotating the steering wheel or shaft" did not seem exact enough for me.... Hope I'm explaining this so it can be understood.

The bump steer kit (at this point) is precautionary and if it isn't really needed then it's just to get the heim joints.....

[Jeff Kleiner]

...For argument's sake let's say that distance is 1.5". I then rotate the steering shaft to opposite stop on the passenger side (i.e. the maximum right travel and measure that same distance from the passenger side frame rail to the inner tie rod pivot point. Let's say that distance is 1". I then move the rack 1/2" to the passenger side (in the slots and with the Breeze bushings). Once that is complete both of the inner tie rod end pivot points will be 1.25" from the frame at stop on either side at maximum travel .....

No, if you do that it will just be opposite of what you have now with the offset to the other side. To get on true center you would move it 1/2 of the difference or .25".

Jeff

[russelljones48]

You are correct. Math used to be a competency for me :-). That's what I've done and each of the ITREnds extends the same amount beyond the frame at full stop on each side. Thanks

[russelljones48]

OK, next question. How much slop (notice I didn't use the term "play") should there be in the steering shaft bearing housing where it passes through the footbox? Mine has about 1/16" or 3/32" and literally rattles around. Seems excessive to me.

[Jeff Kleiner]

OK, next question. How much slop (notice I didn't use the term "play") should there be in the steering shaft bearing housing where it passes through the footbox? Mine has about 1/6" or 3/32" and literally rattles around. Seems excessive to me.

Did you happen to "sandwich" the footbox front wall with the two bearing retainers? If so that's your problem. They both need to be on the same side of the wall; i.e. wall>retainer>bearing>retainer.

Jeff

[russelljones48]

That was it... Thanks. When I read through the directions (DUH) they tell you to mount it to one side - I was just looking at the pics and the photos aren't terribly clear..

[russelljones48]

REMOVABLE PUMPKIN MOUNT. Completed and painted the frame mods so I'm finally ready to install my pumpkin. Since this mod presented a Catch22 for me - I either had to have someone with MIG/TIG come to the house or use my old stick welder - we welded the triangular plate to the frame with my old stick welder. It ain't pretty but with a little grinding and paint it's not really noticeable.

For those who want to create a removable pumpkin mount a few things I found. 1.) Order new FFR brackets - trying to save the ones I cut out was an exercise in futility - note that the brackets aren't centered in the frame so measure/mark carefully 2.) have a Z bracket bent - I used 1/4" rather than 3/16th and then hand cut the back of the bracket to fit the X in the cross tubes - all for $35. 3.) leave a little extra room between the FFR mounting brackets so the mounting area on the pumpkin will fit/slide easily inside the bracket. 4.) locate your bolt holes carefully since clearance on the back side/rear of triangular plate that is welded into the frame is tight. I put one hole in between the brackets and one on the drivers side. I had to put a small notch in the weld on the back side to accommodate the bolt head on the DS hole. 5.) the vertical holes through the 1X2 cross brace were no problem 6.) To make sure that the pumpkin flange is at right angles to the drive shaft I C-clamped a 4' straight edge to the flange and leveled it and measured the distance on either side from the vertical frame tube - in my car about 1/8" on either side - tightened everything up. Thanks to MikeinAtlanta for the idea and MikeN for consultation and welding.... I'm quite happy with the results and can pull and install the pumpkin by myself. I can send pics to anyone who is interested.

[russelljones48]

IRS BUSHING CLEARANCES

Can someone tell me what the bolt to bushing clearance should be for the 3 mounting bolts on the IRS knuckles? I have the knuckles from a '98 Lincoln M8 that have been rebuilt with new poly bushings. I am using the salvaged M14 bolts at this point. They measure about .546" and have what I estimate is about .015 clearance (my smallest wire gauge is .020 and just about fits). When assembled the whole knuckle wobbles a bit which doesn't seem right to me. I also checked the heim-to-bolt clearance on the IRS arms and that clearance is near 0. I have checked the bolts for wear and they don't appear to have noticeable wear - I checked against new M14's and the new bolt measure the same. If this is the right factory clearance does anyone have a suggestion as to how to reduce the clearance to eliminate the wobble?

[russelljones48]

I feel obliged and a little embarrassed to put this post up. After participating in a post regarding the lower rear shock/coil-over mounts where I quoted the build manual, page 137, as saying "the large spacer goes to the rear" and others had recommended putting it towards the front, I pulled the IRS apart (yet again) removed the coils and tested the set up. Guess what - page 137 is WRONG. The lower coil-over mount binds on the lower arm about 1/2 way through its travel. The longer/larger lower bushing needs to be towards the front of the car. Since IMHO this could be a serious problem FFR needs to correct the manual.

Thanks to those who posted on this problem and made the recommendation on how to test the entire IRS for travel. BTW I'm also a little concerned that the UCA needs a bump stop. At max travel it is only about 1/8" from the frame rail above it - any recommendations?

[russelljones48]

So it's been a while since I updated my build thread. I'm just about to the point where I'm happy with the front and rear suspension and will start on the brake system, fuel system etc. I will apologize for my lack of picture loading experience - so no pics but I will send them via email if anyone wants or cares :-)

Here's the summary on my IRS:

IRS Installation details and mods:
1.) Diff/pumpkin 1998 Lincoln Mark VIII rebuilt with Ford Racing 3:55’s and a Torsen style limited slip with new bearings seals etc.
2.) Ford Racing diff rear cover with girdles
3.) Removable rear Diff/pumpkin rear mount (basic design by Mikeinatlanta) – custom fabricated
3a. Polyurethane front mounts
4.) Replaced FFR heims with US made (higher quality)
5.) Replaced all bolts with shortened longer bolts so all “bearing surfaces” of heims and shocks ride on bolt shoulders not on thread
6.) Replaced all spacing bushings with thick wall brass bushing material with proper I.D. i.e. 1/2” and 5/8”
7.) Replaced shock mounting bolts with longer grade 8 flange bolts and nuts
7a. NOTE: page 137 of the FFR manual states that the longer bushing goes toward the rear. Those instructions were not correct for my car. The lower spring mount would contact the lower arm with minimal suspension movement. I reversed the bushings and got full suspension movement with no interference.
8.) Ground welds around various welds so flange heads and nuts fit flat against mounting area
9.) Added 1/2” “doughnut bump stop to rear shocks
10.) Initial set up according to Richard Oben and FFR specs for track, camber and toe.
Pictures via email if you PM me -


IFS updates to come. All of this has taken SOOOO much longer than I wanted and maybe I'm overdoing and over thinking but the changes aren't particularly expensive just a bit labor intensive. I've probably spent almost 2 days at various "hardware" and fastener stores. It's really a good thing that my area has so many race shops and the support structure for them....

[russelljones48]

IDEAS for Wilwood pedal box in a Mark IV

Rather than cut the frame or remove a lot of material from the clutch arm, I've decided to try and use multiple tweaks to eliminate or minimize the the amount of material I need to take out of the clutch arm. I first located a Wilwood NASCAR pedal set and measured the distance between the brake and clutch pedals to determine if it was OK to move them closer together - the NASCAR pedal set had the pedals about 1/2" closer than the FFR set so I think it should be OK to move the clutch pedal to the right. I also checked my Porsche pedals and those measurements confirm that I probably won't end up with the pedals being too close.

So, by shimming the clutch pedal and taking off the 1/16" boss of the inside of the pedal arm I was able to move it towards the bake pedal about 1/8".

Questions:

Can the mounting holes (either bracket or mount) be slotted to move the entire assembly towards the center of the car by 1/8 - 1/4"?

I had another suggestion - has anyone tried shimming "up" the right side of the mount to cant the pedals a little bit away from the frame?

Any other ideas so I can avoid cutting the clutch arm? Comments on the approach?

[edwardb]

IDEAS for Wilwood pedal box in a Mark IV

Rather than cut the frame or remove a lot of material from the clutch arm, I've decided to try and use multiple tweaks to eliminate or minimize the the amount of material I need to take out of the clutch arm. I first located a Wilwood NASCAR pedal set and measured the distance between the brake and clutch pedals to determine if it was OK to move them closer together - the NASCAR pedal set had the pedals about 1/2" closer than the FFR set so I think it should be OK to move the clutch pedal to the right. I also checked my Porsche pedals and those measurements confirm that I probably won't end up with the pedals being too close.

So, by shimming the clutch pedal and taking off the 1/16" boss of the inside of the pedal arm I was able to move it towards the bake pedal about 1/8".

Questions:

Can the mounting holes (either bracket or mount) be slotted to move the entire assembly towards the center of the car by 1/8 - 1/4"?

I had another suggestion - has anyone tried shimming "up" the right side of the mount to cant the pedals a little bit away from the frame?

Any other ideas so I can avoid cutting the clutch arm? Comments on the approach?

I see from you thread you're doing a Coyote. Which sheet metal? The standard FF mod motor sheet metal, or perhaps the modded panels from King? The reason I ask is if you're doing the standard FF mod motor sheet metal, you already will have reduced footspace on the accelerator side. Don't do anything that would move the pedals toward the middle of the car. Even with King's modded parts, which basically restores the space to the same as with a pushrod motor, the space is about as tight as I would personally want it. On the clutch side, I personally think it's important to have enough space to get your foot past the clutch for comfort. If you move the pedals that way, a problem IMO. A lot of words to say if you have something that would put the pedals closer together, possibly a solution. But I wouldn't do anything that reduces the space on either side. My other question is have you tried to install the steering column yet? It runs very close to the brake pedal arm. It wouldn't take much movement to create an interference there, including tipping the pedal box, which I wouldn't do anyway. I personally won't cut the pedal arm. Guys have done it, but not my choice. But the frame mod is literally a couple hour job. I've done it on both of my Mk4's. Frankly, way easier than any of the options you've described here. You asked...

[2bking]

Edward makes very good points. I cut the pedal after doing some fundamental stress analysis and found adequate stress margin with a 50 pound pedal force. Some cut a little out of both pedal arm and frame. Edward has a simple frame mod for cutting the frame.

[russelljones48]

Thank you both. Sorry for the delayed response - I've been out of town. I've read through both of your threads on this topic - as well as through much of your other M4 build posts. Based on both of your posts and my analysis and research I opted to trim the pedal - my skills would pretty much prohibit me from cutting and replacing the frame section.

Very good point on the pedal box. At the moment all I have is the FFR/Willwood pedal box components and haven't seen a new offering for the pre-made extended footbox. If I can't get one pre-made I will probably end up making one myself. Any news on another edition of the extended footbox for the Coyote?

Since King's cut appears to be only about 1/4" - 3/8" I was hoping to minimize it by moving things slightly towards the center of the car. However, based Edwardb's cautions, I will focus on just the clutch pedal and leave the overall box alone until I can assess the whole area.

[edwardb]

Thank you both. Sorry for the delayed response - I've been out of town. I've read through both of your threads on this topic - as well as through much of your other M4 build posts. Based on both of your posts and my analysis and research I opted to trim the pedal - my skills would pretty much prohibit me from cutting and replacing the frame section.

Very good point on the pedal box. At the moment all I have is the FFR/Willwood pedal box components and haven't seen a new offering for the pre-made extended footbox. If I can't get one pre-made I will probably end up making one myself. Any news on another edition of the extended footbox for the Coyote?

Since King's cut appears to be only about 1/4" - 3/8" I was hoping to minimize it by moving things slightly towards the center of the car. However, based Edwardb's cautions, I will focus on just the clutch pedal and leave the overall box alone until I can assess the whole area.

Couple follow-up responses. It's not clear to me whether you've already cut the clutch pedal or not. For the record, on my current Mk4 build the interference is quite a bit more than it was on the first one. I'm not sure what might have changed, but a 1/4 to 3/8 inch cut in the pedal still would interfere in my current build. I just can't get my head around cutting the pedal in the first place, since the genesis of this whole problem is Wilwood made the arms beefier (and a different material) based on breakage in the first place. OK, it was in a different location on the pedal (above the pivot) but still... Just a feeling and don't bother me with the data. Anyway, just make sure before you start cutting that it's not going to take more material than you expect.

One other comment about moving the pedal box toward the center. I just checked my current build. With the brake pedal depressed, the pedal arm is only about 3/16 inch away from the steering column to the right. Quite tight. There is no way I would move that pedal box over any closer. Both brake pedal and steering column are obviously high safety items, and interference just can't happen. Beside, IMO (not mentioned before) you would have to make new holes in the aluminum and steel footbox fronts, plus the bracket that FF supplies to support the footbox on the chassis 3/4 inch tubes on the back side now wouldn't line up properly. If you're not comfortable making a notch in the frame, I can't imagine these would be too easy either.

I've noticed a number of small subtle changes and improvements on my new Mk4 build compared to #7750 from several years ago. So clearly FF is still trying to make the Roadster better. But this is one issue that still exists and it's too bad. Nearly every build references it. I don't think it would be hard to fix in the chassis fixture when the frame is being welded. I've heard (not first hand) that if you call FF and ask about this problem, they say to take a big hammer to the 3/4 inch tube and collapse it slightly. That's maybe not a terrible solution, but again not one that I would be happy with. I should have looked more closely at some of their builds when I was there for the open house in June. Would be curious to see if that's really what they did.

[russelljones48]

Thanks. The only mod I've made is to shave off the boss/bump on the inside of the pivot point on the arm. I have also bought some shims and shimmed the pedal as far to the right as is possible in the cage. Those 2 minor changes moved the clutch arm about 1/8" to the right but only in the cage. The clutch pedal is now that 1/8" closer to the brake pedal. I used a combination of nylon and shims and the ones supplied with the pedal kit to both relocate that arm a bit and tighten up the play in both arms. A Tilton racing pedal set I looked over had "nylon" shims so I'm assuming they will work fine and reduce play and rattles.

I really appreciate your comments and the effort you've made to check your build. Your advice is well taken and I am going to wait to see what the whole area looks like assembled. I can't imagine taken ye old sledge to that tube although I considered getting a porta-power in there I think the area is too close to the 3/16" plate and the weld. Would be afraid of breaking the weld or worse.

And I agree with you although you can probably set the pedal up high enough to avoid needing to make these mods it seems unacceptable that this hasn't been fixed by either FFR or Wilwood - especially since the Wilwood racing pedal box I measured had the pedals close enough to probably solve this problem.....

[russelljones48]

Mike Noyes stopped by to help me triple check the initial suspension set up and then to discuss this pedal box problem. He had what I think is a great suggestion that looks like it will solve the problem with my minimal fabrication skills: Proposal:

1.) Cut the frame tube just inside the bulkhead
2.) Bend the tube to the outside 3/4" so that (if extended) it would be parallel/side by side with the original tube on the front side of the bulkhead
3.) Insert about 8" of 9/16" square steel rod about 4 inches into the piece inside the footbox so that the 4" extension is parallel to the outside piece of the frame tube
4.) Insert about 4" of the same tubing into the piece in front of the bulkhead.
5.) Drill and bolt the side by side pieces together
6.) Drill and bolt the piece inside the frame rail that's still in the footbox

This is quite similar to Edwardb's mod but does not require cutting a piece of the frame out and should only require hand tools. I'm off to get some square steel rod.. Comments please. BTW I checked a completed M4 Coyote this morning (Thanks Alex P) and the extra piece on the outside of the bulkhead/footbox shouldn't interfere with anything in the build.

[russelljones48]

It was a little more involved than I originally thought but I'm very pleased with the results. It worked just about how I described it above but I will document completely when I figure out how to load pics> For the moment I hope I can get the picture of the final installed "fix" into this post.

[russelljones48]

20151008_191309 (1).jpg

So, IMO this is a simple and straightforward fix for the Mark IV Wilwood pedal box clutch arm problem. Basically it's: cut the 3/4" square tube at the inside of the bulkhead, bend it to the outside so an inserted 5/8" square steel rod will run parallel to the remaining piece outside of the bulkhead. Insert a 5" piece of the 5/8" square rod from the bulkhead forward into the piece that is forward of the bulkhead. Create and 8" piece of the 5/8" square rod and insert 4" into the piece inside the pedal box - drill tap and screw. Drill, tap and screw the piece forward of the bulkhead to the original piece in front of the bulkhead.

THANKS to Mike Noyes for the idea on this and for consultation on the mod....

The clutch pedal now moves all of the way to the end of the footbox with no interference. All of this was accomplished for $10 and mostly hand tools. I did use my bench top drill press but could have used a hand drill - so all of this can be done with hand tools. More pics and description to come.