DuPuis Family Cobra Build

tmyers said:
Are you using aviation style rivets or cherry pops?

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They’re pop rivers in the kit, that’s what I’m usung.
 
This afternoon I got the midshift kit installed in the transmission as well as cut off the bottom mount that you need to remove to make the thing fit into the car properly. Really an easy job, takes about half an hour working slowly, but it’s nice to have that one done. Maybe tonight I’ll mess around with the brake and fuel lines some. Those definitely fall under the “jobs I don’t want to do” category”.

I received a good number of requests for a video review of the Speedmaster downdraft EFI setup I bought. Here are my initial thoughts those interested.

 
Zeldman said:
Both used together.
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Sort of what I’m thinking. What I’m also wondering is if I should put some silicone around the intake gaskets, at least the parts that have coolant. The heads and intake are smooth so theoretically it shouldn’t be required.
 
Wish we were closer, would love to wrench with you.

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Ted DuPuis said:
Sort of what I’m thinking. What I’m also wondering is if I should put some silicone around the intake gaskets, at least the parts that have coolant. The heads and intake are smooth so theoretically it shouldn’t be required.
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On the intake gaskets we used a spray sealer that also held the gaskets in place while installing the intake. We would spray the gasket, both sides, then place it on the head, followed by the intake. Now remember that was over 25 years ago, but we never had coolant leak into the intake. And we were using Fel-Pro gaskets.
 
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What spray sealer was it, @Zeldman ?
 
I knew you would ask that....:lol::lol::lol:

Too much water done gone under the bridge...... I am pretty sure it was something we got at the local NAPA store.
 
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I remember using a spray on gasket adhesive as well ... and my memory sounds like @Zeldman's ... something like 'copper tack' seems to jingle a little bell way back in the recesses ... might have been Permatex?
 
gkainz said:
I remember using a spray on gasket adhesive as well ... and my memory sounds like @Zeldman's ... something like 'copper tack' seems to jingle a little bell way back in the recesses ... might have been Permatex?
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There was a copper something that we sprayed on steel head gaskets before we started using FelPro head gaskets. Could that be what you are thinking of.??

For the intake gaskets I am pretty sure we got the stuff from NAPA. The local NAPA store was owned by a bunch of hot rodders and they could get us the good NAPA brand stuff, not the stuff they sold in the store.
 
Zeldman said:
There was a copper something that we sprayed on steel head gaskets before we started using FelPro head gaskets. Could that be what you are thinking of.??

For the intake gaskets I am pretty sure we got the stuff from NAPA. The local NAPA store was owned by a bunch of hot rodders and they could get us the good NAPA brand stuff, not the stuff they sold in the store.
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We used to use K & W Copper Coat on our head gaskets, I don't recall using it on intake gaskets. Permatex makes a spray on copperized gasket sealer, it seems to be well received, but I've never used it. We generally avoided using sealers if we could avoid it, but that's a racer thing since we took things apart so frequently.
 
Got a bit more time in the garage this evening to get the brackets for the front brake lines installed. This is another one of those areas where the assembly sequence really is sub ideal, although I'd argue so are the brackets that I bought. Or one could argue the design of the F-panels in the front wheel wells. I got them riveted in but the forward rivets were hard to get at. I did confirm no binding and sufficient clearance from lock to lock, so it ought to work. Tomorrow I hope to get the rear brackets on, and maybe start on some of the hard lines. There's a few other things I can do but not a ton really until I get a few more detail parts in.
 
I used a brush-on Permetex gasket sealer for the intake gaskets, similar to the spray-on. It’s cheap insurance and helps hold them in place if you’re working alone.
 
Spent a couple hours in the garage this evening. I spent the day more playing with the kids - we were all feeling pretty lazy and tired. But I did get out there to check a few things.

First one was taking a look at the polyurethane motor and transmission mounts that I ordered from Factory Five. I installed the transmission mount on the transmission, and then after taking a look in the transmission tunnel of the car it makes sense where it mounts to the car, and also why I had to trim part of the tail housing off of the transmission to make it fit over a crossmember.

Factory Five included the bolts I need to bolt the mounts to the engine and transmission, but oddly they didn't include the washers that to me look to be required. This kit seems to lack a lot of washers, not sure why. In the case of the motor mounts they're especially needed as the bolts they supplied bottom out in the block. So I'll pick those up.

Then I finally got moving along on the brake lines. I wasn't looking forward to this, and decided to start with the crossover line for the front brakes that goes from the front right to the front left (where there's a T-fitting that then goes up to the master cylinder). What a pain that was. Factory Five supplies a bunch of 60" hard lines, and they say one 60" hard line will work for the crossover line. They're correct on that, but because I went with non-Mustang brake hoses (I did a popular upgraded kit that seems to work ok) the brake hoses mount slightly differently, which made the total distance the brake line had to travel a bit longer. Just enough that I had to do a different routing from what Factory Five recommends and had to then do a loop because 60" was too long going that way. Still, I managed to get it done. Not as attractive as I would like it to be, but it is functional and safe so unless I see problems later on in the build, I'll leave it be.

I then got working on the rear, which once I got into it I realized that I should've done first as it's easier. I ended up not making any lines other than the first one connecting to the master cylinder, but it's apparent that this will be easier all around, not to mention less visible after it's done since the front hard line will be visible when you open the hood. I need to buy a tee for back there (the kit only came with one tee) and then also one 24" or so hard line to go from the master cylinder and I should have everything I need. The 60" hard lines will need a couple of extra loops to use up space for the rear brakes, but it'll work. Might get that done tomorrow night, we'll see.

I'm mulling over what I want to do with the pushrods and valve adjustments. My measurements made me figure that 8.100" pushrods would probably be about perfect. However what I measured was technically 8.104", so that would be a hair looser, and thus give me no room for making things tighter. The next sizes up are 8.125" or 8.150" and then I'd have to shim underneath the rockers. The Ford Performance shims only go down as low as 0.010", but it would be simple enough to also buy some shim stock in thinner thicknesses and make my own shims from there to dial it in just right... which is how I like to do things. Something to sleep on.
 
I may be confused by the wording, but are you talking about taking up extra slack by making loops in the hard lines?
 
Putting loops in the brake lines in strategic places can help reduce fatigue fractures due to vibrations.
 
Zeldman said:
Putting loops in the brake lines in strategic places can help reduce fatigue fractures due to vibrations.
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This is true. I'm not sure how strategic the loop I put in the front line was, but it's there and it does its job. :)
 
Ted DuPuis said:
Yes.
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Why not just cut where needed and re-flare the end to avoid making loops?


Zeldman said:
Putting loops in the brake lines in strategic places can help reduce fatigue fractures due to vibrations.
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Hadn't heard of that one, but I suppose it makes sense. I'd think rubber isolators would be as effective though.
 
SoonerAviator said:
Why not just cut where needed and re-flare the end to avoid making loops?



Hadn't heard of that one, but I suppose it makes sense. I'd think rubber isolators would be as effective though.
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Firewall and frame can flex and twist in different planes. Also, despite best efforts, we can't all get the solid line terminated in exactly the right place, adding additional stress to the line by forcing it into place.

I can't imagine a rubber isolator being anywhere near as effective on relieving stress as a nice coil. Heck, as long as the fitting ends in the right neighborhood, it will likely work.

 
ElPaso Pilot said:
Firewall and frame can flex and twist in different planes. Also, despite best efforts, we can't all get the solid line terminated in exactly the right place, adding additional stress to the line by forcing it into place.

I can't imagine a rubber isolator being anywhere near as effective on relieving stress as a nice coil. Heck, as long as the fitting ends in the right neighborhood, it will likely work.

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Hmm. Well I just did exactly what they said not to do. I've not heard or seen that recommendation before.
 
ElPaso Pilot said:
Firewall and frame can flex and twist in different planes. Also, despite best efforts, we can't all get the solid line terminated in exactly the right place, adding additional stress to the line by forcing it into place.

I can't imagine a rubber isolator being anywhere near as effective on relieving stress as a nice coil. Heck, as long as the fitting ends in the right neighborhood, it will likely work.

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Why do you need two turns in that pigtail? Just asking...not a criticism. I'd have thought one turn would have been sufficient.
 
Ted DuPuis said:
Hmm. Well I just did exactly what they said not to do. I've not heard or seen that recommendation before.
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Pedal box note? Neither have I. Just pulled the first random google image that came up.

Guess it also depends on how close the header is to the pedal box for that application...
 
ElPaso Pilot said:
Pedal box note? Neither have I. Just pulled the first random google image that came up.

Guess it also depends on how close the header is to the pedal box for that application...
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Yeah, the manual doesn’t say it and their recommendation goes against what another fellow who’s been building these for 20 years told me.
 
Gotcha, I guess I was imagining the coil being placed near the caliper hose connections, not in a location potentially subjected to movement in more than one plane (like going from frame to firewall like in the pic)
 
I could see their point in some cases. One of the problems with building these cars is that it's like having a kid - the first time you do it you make all the mistakes, and then the second time around you do things better. Indeed, some folks build a bunch of these cars. I'm more likely to see what I don't like and make modifications as much as I'm able.

At this point there's no doubt that I won't make my son's first day of 1st grade with a driving car. That's about a month off, just not going to happen. Too much work that needs to occur between now and then, and the motor's not in. But for now anyway, November 11th (Ford v Ferrari opening day) still looks doable. Depending on how quickly Summit ships some of the components, I may even opt to get the engine and transmission in this coming weekend with my wife around to help (definitely a two person job).
 
Now I realized I forgot to include what I ordered.

I ended up ordering 8.150" pushrods (note that per my measurements, "perfect" was 8.104"). This will requiring shimming for sure but will also give me room to both tighten and loosen things up as the engine wears in. So that's a good thing. I also ordered the Ford Performance shims, but those only go down to 0.010" (which is definitely not enough) so I also ordered some thinner shim stock that goes all the way down to 0.001" to be able to make the shims I need to get the valve lash exactly right. I checked the rocker this morning and I don't see any problems with the geometry coming up, although once I get everything shimmed I'll also need to double check and make sure that remains true.

I also ordered some more fittings I needed as well as the ARP bolts for the camshaft and oil pump so that I can put those on and not be worried about them working.

Normally Summit is 2-day shipping for me so I should get parts by Thursday or Friday. I also normally don't get much time working on the Cobra when Laurie's home (she comes home tomorrow) so it's entirely likely that I won't work on anything until next week. Although if the pushrods show up I'm sure I'll at least throw them in and start putting the rockers on. The full shimming to get things right will take a while, though...
 
Last night I spent a few minutes in the garage and checked out the timing covers. I have two timing covers, one off of the first 302 parts motor I had (which originally came from something like a 74 Lincoln) and one off of the second one (from a 95 Mustang). The timing cover style changed in that period. The bolt holes/pattern are the same, but the water pump hookup is a bit different. The 95 Mustang also has some extra nubs on the inside for reasons I'm not entirely sure of.

There's a piece of metal cast in that normally goes between the two halves of the timing chain. With the timing gears that needs to get removed, and if I use the newer timing cover it looks like I also may need to remove the nubs on the inside, but I'll have to see on that. Either way, not a big deal.

The big thing that this drives, though, is that I'm going to need to order my water pump (since I'm going electric) in order to determine which cover I'm going to go with and modify that. Obviously I needed to do that anyway eventually, so I think after I get further along on the fuel/oil lines and finish up the valve adjustments I'll order the water pump and whatever else I'll need at that point to finish up the main engine.
 
I posted a video that I recorded this weekend about doing the mid-shifter installation:


Summit Racing confirmed that my order had been shipped and should arrive today. The shim stock arrived last night, too. So then it's time to start shimming and getting the valve lash right.
 
Got my pushrods last night, as well as my Ford Performance shims for setting the pedestal spacing. I worked on the first cylinder last night but didn't go beyond that.

As expected, it's a good thing I ordered the shim stock. I thought I still understood basic geometry and apparently I do. The Ford shims are 0.010", 0.020", 0.030", and 0.040". Because of the 1.7:1 rockers, 0.010" worth of spacing on the rocker results in 0.017" change in lash. Obviously this isn't anywhere near close enough. Having shim stock down to 0.001", I can get to within 0.0017", which is good enough.

However I'm not going to try to get that close. Since the valve lash is supposed to be measured hot, my goal is "within tolerance". Theoretically cold lash should be 0.006" tighter than hot lash spec on aluminum heads and I'm aiming for 0.004-0.008" tigher than spec anyway for a little extra lift and duration. Spec is 0.022" hot, so that'd put me at an ideal of 0.008-0.012". I figure if I get anything in the range of 0.012-0.016", that's good enough for now, and even a bit beyond that is fine. Once I get it running I can get hot measurements and then make adjustments accordingly.

But we have other projects this weekend, like putting the hydraulic cylinders back on the bulldozer, tune-up on the front end loader, and some other house related projects. So I might do some work on the car but that'll probably be once Laurie heads back to work on Tuesday.
 
I ended up spending a bit of time in the garage this evening and shimmed the passenger side head.

About half the valves I was able to get "close enough" with one of the 0.0x0" shims (20 or 30), but the other half 30 was far too loose and 20 was far too tight. Keep in mind that the theoretical ideal is 0.008". 0.008" is a hard limit for me on the tight side, and on the loose side I'm making 0.016" my hard limit. Then I'll do the final/proper adjustment once I run the engine and get it warm.

I had to think about the best way to make shims using the thin (in tonight's cases I ended up using 0.002") shim stock. The shim stock itself is of course extremely easy to cut - a knife or box cutter can do fine, so would any pair of scissors. However the catch is drilling the hole in the middle of the shim for the bolt to go through that holds the rocker in place without destroying the material. The solution I found was to take two of the 0.040" shims, sandwich the 0.002" shim stock in between, put vice grips on either side, and then gently run my drill through with the appropriate (5/16") bit. That's worked very well and the shims fit perfectly, none destroyed so far that way.

When I run the engine and get it hot to check hot lash, it'll be easy to simply measure what the lash is, and then calculate how much shim wise I need to add or remove to get it where I actually want it. That is unless I've completely screwed up.

Another thing is that it's good I bought the 8.150" pushrods. I'd figured that with 8.104" being what I measured as probably needing that I'd be adding 0.050" or so. Turns out 20-30 thou has been about the average on this bank, although the other bank seems to have been shaved a hair more and need 40+. So looks like these were the perfect size.

One thing I'm now thinking about is whether I want to put the intake manifold on once the valves are adjusted (I wanted to wait until I got all the rockers on and valves adjusted first) or wait until it's in the car. I'll likely put them on with the engine on the stand but I do want to look at it a bit more first.

2019-07-26.jpg
 
Holes in shim stock is where punches shine. Now unless you have a wide range of sizes in a diacra turret punch, I’ll admit having one the right size can be a problem.
 
-KLB- said:
Holes in shim stock is where punches shine. Now unless you have a wide range of sizes in a diacra turret punch, I’ll admit having one the right size can be a problem.
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Yeah, that would be easier. But I don’t have a bunch of punches.
 
PaulS said:
Nice, no price, care to share for the morbidly nosy? Also, I grew up with carbs, they suck, figuratively and literally, I will not buy another carb vehicle unless I absolutely have to, I hope it runs well for you.
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Guess I’m curious about the origin of the engine. Y’all keep referring to carbs but I know that Mustangs from that year (per the photo) were all fuel injected. I own an ‘01 Mustang Cobra since new. It is a 4.6 liter normally aspirated with fuel injection and puts out 390 horses. It will flat out get up and go. Can’t imagine having to go back to the days of carburetors. As the previous contributor said, they suck


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I'm beginning to think Ted's project is going to be finished sometime around Christmas Eve 2000. ;)
 
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3393RP said:
I'm beginning to think Ted's project is going to be finished sometime around Christmas Eve 2000. ;)
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That is the era I’m shooting for technology wise.
 
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