S2's Build Thread

Not a big fan of the torched color, it just looks artificial and overdone...like cheap ricer exhaust tips. As-is or cleanup and let the heat do the coloring for you. Beautiful work on that system, though.
 
win either way. the blue exhaust can look great..or it can look fake. If it turns out ugly you can always start over. Your welder is legit.
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Scott

Lifetime Supporter
Thanks for the feedback regarding how to treat the titanium. I’ve decided to remove the alpha case with Scotch-Brite pads and then let the heat cycles do what they will.

In a previous post I designed brackets that mounted the heatshield to threaded bosses on the transaxle via vibration/heat isolators. The next step was to hang the X-pipe from those same brackets via a different set of isolators. I considered fabricating the hanger from titanium and welding it to the X-pipe, but given the size I figured that it would be difficult to get it perfect and I could damage it when not on the car. Instead, I decided to weld threaded bosses to the X-pipe and laser cut a piece of 6061 to connect the bosses to the bracket.

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Blue isolator mounted to transaxle boss (top-left of bracket), heatshield (bottom of bracket), blue isolator supporting the hanger (middle right of bracket), hangar (long vertical piece) and threaded boss tacked to the X-pipe.

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The bosses are visible in this viee. Note that the hanger is too long, so I’ll laser cut new ones. If this piece were titanium welded to X-pipe it would be messy to fix.

I fabricated threaded 1/4”-20 bosses from 1/2” Grade 5 titanium rod. With aluminum, stainless steel or 4130, I’d have the material laying around and the machining would be straight forward. However, titanium is a different beast. A 6” piece of 1/2” rod cost me $33.85 and part way through my first tap hole I wrecked a high-quality, made-in-the-USA drill bit. After replacing it with one specifically designed for titanium I quickly determined that my tap was a no go. NFW was I going to finish the hole without breaking the tap.

Apparently, titanium’s low modulus of elasticity makes it “springy,” so the workpiece tends to close in on the tap causing galling and tearing of the threads which increases the torque on the tap. Taps designed for titanium have a different coating and spiral flutes, so I ordered a $47.17 tap from McMaster. With tools, my general philosophy is “buy once, cry once” and while McMaster charges a premium, I get it one day and I don’t need to worry about quality.

In any event, my takeaway for titanium is that in addition to material the tooling and machining costs are noticeably higher.

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From left to right; 3-jaw chuck, titanium rod, tap, tap handle, spring-loaded tap guide, and Jacob’s chuck mounted in the tailstock. This horizontal can approach can be used vertically in a mill or drill press.

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Note the indent in the top center of the tap handle that receives the tip of the spring-loaded tap guide.

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Titanium tap. Made with cobalt steel, a high helix angle and an open spiral flute design to provide the cutting strength needed to tap threads in titanium.
 

Scott

Lifetime Supporter
Colin,

I didn't know that titanium could be anodized. I found lots of pictures of anodized titanium, but none of exhausts. Do you have any pictures/link of an anodized titanium exhaust?
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The O2 sensor bungs and exhaust cutout tubes have been installed in the catalytic converter assemblies. The notch on the cutout tube was tricky because it forms a compound angle on a cone and the cutouts have very little clearance. Good thing this isn’t Abe’s first rodeo.

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Ferrari 812 Superfast catalytic converter

You may be thinking that replacing the catalytic converters will be an expensive endeavor. Yep, but there wasn’t space to do otherwise. However, I’m apparently in good company. Abe recently worked on a Ferrari 812 Superfast and a catalytic converter costs $6,350.73, so that’s probably over $15k if you bring the car to the dealer!

The next step is to connect the exhaust cutouts to the X-pipe.
 
I don't know how well the anodizing would hold up under high temperature but it's such an easy process it wouldn't be hard to test it out.
 

Scott

Lifetime Supporter
I decided to locate the engine oil breather can aft of the engine to reduce the potential of fumes making their way into the cockpit. I wanted to use a Peterson Fluid System’s breather because it features a lightweight, high-quality spun aluminum canister, hand TIG welding, proper baffling, etc. However, like most things on this project, it seems like I wind up customizing even the products. In this case, all of the AN fittings were too small and in the wrong location. I called Peterson to order the parts and they refused to sell them. Why? Because they used to do that and their products began appearing with welds that don’t meet their standards which undermines their brand. Wow, they’re willing to walk away from a quick sale to maintain their post-sale quality. They’re also too busy to fabricate custom breather cans. So, I did some begging and pointed the sales rep to some pictures of Abe’s welding on my website, he ran it past his boss, and they sold me the parts.

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Reservoir breather tube with Wiggen’s fittings on both ends, custom standoff, and breather can with two male -12 AN bungs and a -16 Wiggen’s bung, all welded by Abe — Peterson’s brand was in good hands.

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I’m constantly surprised at the number of parts I make or modify on the lathe. This simple standoff for the vibration dampener was made from 1/2” stainless rod. After drilling and tapping it the full length, I decapitated a stainless-steel screw, threaded it part way in welded it in place to form a permanent stud.

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One of the vibration isolators is mounted to the rear chassis brace and the other is mounted to the scalloped 2” x 2” chassis rail


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Vibration isolator with custom standoff, all of which is hidden by the induction tube.


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The -12 bungs are hidden under the rear chassis brace

To mount the breather can, I laser cut a bracket from 1/8” 4130 and welded it to the underside of the rear chassis cross brace. The breather tube for the oil reservoir tank was fabricated from 1” OD aluminum. Both the breather can and the reservoir mounting clamps utilize rubber to provide vibration isolation. Since everything will vibrate at different frequencies, I isolated the breather tube with Wiggin’s fittings on both ends and two rubber vibration-damping sandwich mounts. The brackets for the isolators were laser cut and bent by SendCutSend… fabricating parts that small by hand is awkward.

In a previous post I upgraded the coil packs and relocated them to the upper chassis tubes. This provided an opportunity to upgrade the valve covers to something without the coil pack mounting posts. I found a billet set without an oil fill and -12 ORB breather ports in an ideal location for my purposes.

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-12 ORB breather with welded baffle (left side). No chance of it coming loose!

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After installing the valve covers, I realized that I have a lot of billet on the engine with matching ball-end finish. All of it is from down under; bellhousing (Albins), valve covers (Shaun’s Custom Alloy) and intercooler manifold (Harrop).
 

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Howard Jones

Supporter
I think you will get a lot of oil blown out of the breathers with them oriented horizontally. The valve covers will hold quite a bit of oil in them when the engine is running at even moderate RPM's. As you can see mine are on the top so the oil needs to travel vertically about 3 inches before it can leave the valve cover. I drain about a pint out of mine after each track weekend (about 250 track miles). Your arraignment looks like less than an inch. The oil depth in the valve cover would be at least that deep under hard acceleration at the rear of the valve cover.

Sorry to tell ya that. But at least the valve covers are still clean and you can move them to the top between the rockers before the oil contamination makes welding more difficult. You have done some very talented work. I'm sure this would be a very small thing to fix for you
 

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Scott

Lifetime Supporter
Howard, thanks for the advice. I had a similar concern, but when I spoke to guys at Steve Morris Engines they told me that it wouldn't be an issue. They build engines from 900 to 4,500 HP (billet block) and have experience with these valve covers. According to them, if I have that much oil in the valve cover I have a problem. I also think that my cog-belt-driven Daily Engineering dry sump would reduce the amount of oil being blown out the breather port. If I flow a lot of oil out and that's not related to some other issue, I'll fabricate a vertical 180-degree loops out of aluminum tube which is fairly easy to do. Time will tell...

The hard line from the reservoir slopes upwards, so I don't foresee any issue there.
 

Brian Kissel

Staff member
Admin
Lifetime Supporter
I agree with Scott. The guys at Steve Morris really know their stuff. I’m pretty sure they are going to build my BBC Lola engine. It is between them and Scott Shafiroff. Morris is about 50 miles away and a really down to earth guy. He has some really good informational you tube videos also.

Regards Brian
 

Howard Jones

Supporter
I think it's all in the intended usage. Street engines return to idle often and spend nearly all their time at relatively low RPMs. These conditions allow for the drain back of oil in the upper areas of the engine. They also produce far less crankcase pressure and gas volume due to the low revs and resulting power production. My GT40 is like that now that it is a dedicated street car, I see very little oil in the catch tank or on the breather filter.

However, the SLC runs above 3500 rpms for 30 mins at a time with a 6200 gear change. Something like 20 per lap. So a low and rear vent would not work for me. My intention was to alert you to this now before the valve covers get hot oil all over the inside and require a big cleaning before welding to correct this. I personally have had many "attention to detail" PM's from concerned members on this site that have helped me immensely over the last 20 odd years.

Just sharing the love.
 

Scott

Lifetime Supporter
Howard, I'm happy to have the love!

The exhaust cutouts now flow from the expansion cones that precede the catalytic converters to the X-pipe. There is very little space between the transverse chassis billet member and the bottom of the transaxle, so I used 2.5” tube. Given that the rest of the cat-back system is 3.5” and the angle is a bit steep, not all of the exhaust will flow through the cutouts. No big deal… the cutouts are about sounding bad ass rather than maximizing power and I can show the neighbors how much restraint I employed LOL.

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Cutout to X-pipe junction is tacked

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180-degree cross over tubes (left), cutouts (middle-to-right) and X-pipe (far right)


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The next steps are to fabricate the exhaust tips and heat shields.
 

Brian Kissel

Staff member
Admin
Lifetime Supporter
That’s freaking awesome Scott as per usual. The craftsmanship that’s going into this build is second to none.
Congrats on the progress.

Regards Brian
 

Scott

Lifetime Supporter
Other than the exhaust tips and ceramic coating, the exhaust system is done. I now need to fabricate eight heat shields to solve all of the self-inflicted heat management challenges. The first heat shield protects the transaxle from the X-Pipe and exhaust cut outs.

The heat shield was fabricated from 0.048” stainless steel. I chose it over aluminum because it would warp less during welding, it has significantly lower thermal conductivity and it allowed a thinner material to be used.

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It was fairly involved to get right:
  • 11 laser-cut pieces
  • 20 CNC bends
  • 7 heat/vibration isolators (purple parts)
  • A fair amount of welding (green pieces to the gray piece
These parts required me to learn a few new sheet metal tricks. The recessed box required five corner bend reliefs. Fortunately, SolidWorks has a specific feature which makes that easy. The two sloped sides required me to modify their flanges. Specifically, the CNC brake operator pushes the edge of the part into a back gauge to ensure that the depth and angle of the bend is correct. This requires that edge to be parallel to the bend line — which it wasn’t.

As can be seen in the picture below, the solution was to extend the sloped sides to create an edge parallel to the bend line. The extension is attached via small tabs to facilitate removal. After the part arrived, I cut the extension off and sanded the edge smooth. The tabs required more effort than I anticipated to remove. I took a closer look at SCS’s guidelines and it recommends that the tab width is 50% the material thickness which seems right (mine were twice that wide). They also recommend that each tab is spaced out by 1x the material thickness which seems a seems a bit excessive. I had the corners precut so I only needed to sand the straight edge with the tabs.

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The sloped side has been extended to create an edge that’s parallel to the bend line. The tabs facilitate the removal of the extension.

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Welding has been completed. Small stitch welds were used to reduce warping.

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I 3D printed sections of bend profiles to check fitment and SCS’s bends were spot on. Note that the holes in the stainless have 0.74” doughnuts welded to the outside to provide the correct thickness for the isolators.

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The dropped box on the right side accommodates the pneumatic shift servo

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Front view

The fit was excellent. Once I finish the remaining seven shields, I’ll have them ceramic coated with Cerakote and I’ll apply one of the ZircoFlex or ZiroForm products to the underside.
 

Scott

Lifetime Supporter
The left merge collector is where the stock oil filter goes, but even with a dry sump pan I had to modify the oil inlet fitting as described in a previous post. After all of that work, things are still danger close. The only route to the inlet is to cross the oil line in front of the bellhousing. Fortunately, the shallow dry sump pan provides lots of room. The first step was to fabricate a cover for the bellhousing that also provides a mount for the oil inlet line and a heat shield. The cover was laser cut from 0.100” stainless steel and the three mounting tabs for the heat shield were cut from 0.187” stainless steel.

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Bellhousing cover (gray) with welded mounting tabs for the heat shield (green)

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To ensure optimal line routing AN fittings were welded to a mandrel-bent stainless tube which was mounted to the bellhousing cover with P-clamps. Thermal sleaves will be applied to the stainless and flex tubes.

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The oil inlet fitting is danger close to the left merge collector (show above) and the oil line also runs parallel to the right merge collector and the exhaust tubes that run under the oil pan, all of which requires heat sheilding.

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The heat shield was fabricated from three laser-cut parts, nine CNC bends, one hand-formed curve and one manual bend. The CNC bend lines are shown as faint lines with the large gray piece have some unwieldy bends.

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The heatshield is welded and ready to install.

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The heatshield is installed via three button head screws

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Everything fits like a glove. No way could I have achieved that doing manual bends!

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The heat shield wraps around the bellhousing to protect the stainless steel and flex tubes. The bend on the curved piece had to be done after the curve was formed, so it was done manually in a brake.

I still need to Cerakote the shield and figure out what heat mitigation materials I’ll attach to the shield. Only eight more heat shields to go.
 
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