Fast, A long time ago (10 yrs+) I was inquiring about one of these heads and was told they had an oiling problem. I don't know if it was in the lifter area or the head itself. I don't remember if it was the guy that ran FOCOA or his mechanic that had the Green Machine. Was wondering if you ever heard of anything along those lines. If so what did you do to address the issue?
It was either Keith Huff or John Parenti that told me that. Both were in FOCOA at the time and Keith is somewhere in AZ now. Don't know about John. Just don't want to see you blow it up. I've noticed a few SD block for sale that had rods go threw the side. I don't know how they address the issue of eliminating the lifters and that might have been the problem. Oh well, hope I'm wrong. Just wanted to give you a heads up
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85 GT 3.4 14.9 @ 90 1.9 60' Old TH125/3.06 Unknown New 4T60/3.42
The lifter bores are inserted with aluminum plugs. At this stage I've been seriously considering moving to a dry-sump oiling system so I can provide pressure feed to critical areas in the head like the cam bearings. It will probably have to be something I do when the engine is being set up in the car with all the accessories, since I'll have to move to a Gilmer-style drive.
After finally tracking down someone who had 321SS tube in 16g and waiting to get it from SPD Exhaust, I formed the stainless transitions using my new mandrel, and they work great. Matches up with the flange and looks good to boot.
Wow, tried to read thru but had to jump to the end... I am in the parts acquisition process to build a SD4 16V turbo engine myself. Please keep those CNC coordinates so I can buy some flanges form you! I'll check in when my parts arrive here. I have to ask if you have any spare bottom end stuff, rods, pistons, crank, block?
Wow, tried to read thru but had to jump to the end... I am in the parts acquisition process to build a SD4 16V turbo engine myself. Please keep those CNC coordinates so I can buy some flanges form you! I'll check in when my parts arrive here. I have to ask if you have any spare bottom end stuff, rods, pistons, crank, block?
I always save all of my models. What I can make depends on how much spare time I have, but I can always send you the CAD data. Any competent shop with a CNC machine would have no trouble knocking these out. I don't have any spare bottom end stuff, but if you keep looking I'm sure you'll find something. Just do a daily search on eBay and it will pop up.
The bolts are stand-ins, they're too long. The proper bolts will ride inside of the counterbores. The new flange ID is .010-.020" smaller than the port on the head, but there's plenty of material to take it out to a ported match. I'm pretty happy with how it looks, just have to make 4 more now out of a proper weldable aluminum alloy.
I am ready for a set of intake and exhaust flanges. About to unpack 5 boxes of Cosworth stuff. Only lacking a 2.7L 3.25" crank. I'll send a pm to follow up.
So I've been working on the flywheel situation. For the last several years I had contemplated running a reverse-mount starter through the tranny bellhousing and in conjunction with a reduced diameter flexplate. I'm still not sure what tranny I'll be running, so I've decided to bite the bullet and just set up with the stock starter position / iron duke ring gear.
I still have an issue caused by the large SBC crank pattern messing with the friction insert. I've analyzed this to death, saved weight everywhere I can, and I think the result is looking very good. Total weight is almost 3.5lbs with ring gear. Inertia for the assembly is about 50lb-in^2. Total including a Tilton Carbon-Carbon 5.5" would be 8.1lbs and 74lb-in^2, a savings of.....alot.
However, I did a little re-evaluation of objectives and I examined the alternate route of retaining the mini steel flywheel, and basically just making a flex plate. The weight for the assembly isn't much worse (4.6 vs 3.5lbs) and the inertia is only moderately higher (61 vs 52 lb-in^2). What's pushing me towards this is that I don't need to mess with a friction surface, it can take thrust loads from the TOB more easily, and if I mess up the flywheel I can toss it and get a new one for around $100-150, which is about the same as most friction surfaces. If I go to a bellhousing mount starter I can just toss the flexplate in the garbage. Right now I'm wondering if the inertia will be too low and my non-racedriver skills won't be able to hack it with nearly instantaneous throttle response. The crank will only add about 70 in-lb2 of inertia. I'm looking at a total rotating inertia 60-90% smaller than a typical V8.
With flywheel weight/clutch choices I always ask what the use/application will be. Street or track? On the track I would get the lightest in my budget. However,with a street car,I would suggest of not going lighter than10-12lbs for a flywheel.You do need some inertia for pulling away from a stop. At first you may say that you will adjust your driving style to deal with the ultra light FW, but over time it will become a royal PIA.I also stay away from multi-disc clutches on the street,especially carbon/carbon. They just don't like being slipped/modulated to the level needed for street driving . I guess it comes down to how much,where and how you will be driving the car when done.
I got my aftermarket ring gear in several days ago. It's only about a 1/4" wide (ID-OD), so the ID is about .25" larger than the stock '85 Duke ring gear. This doesn't leave me enough room to pin or screw it onto the flexplate. I wanted something with a SMALLER ID than the stock gear, so I had enough room to at least get some #10 fasteners in. Without any additional shear holding, using a shrink fit, the ring gear would be able to slip on the aluminum center at my worst case accel-decel scenario.
Does anyone know of any smallish-ID 142 tooth ring gears?
In other news, I finally got my car moved to my shop
Never heard an SD4 before, sounds very interesting, almost as if it has a constant rod knock. Great looking Indy though, looks like its a lot of fun to drive!
Can't speak for every SD4 out there, but I have 2 and they both have that internal rattle to them. Both have Jessel rockers and I have been told that it could be those. However I have noticed that every stock Duke Fiero I have ever owned has sounded like a rattling bubblegum machine to varying degree's so it could just be an inherent noise with the design of the engine, which is pretty much the same between the SD4 and the duke.
When i first got the Indy it had a hooker header on it and a straight pipe exhaust with no muffler. You could not hear the rattle for obvious reasons with that set-up.
But there are ppl here more knowledgeable about SD4's here than I am who might be able to shed some light on this.
Nothing exciting right now, I've been working on machining some assorted flanges, and I'm still trying to get a flywheel design ironed out that won't cost me an arm and a leg for raw material for. I've also been doing some things to the car, cutting/repairing rust around the battery tray. Money is tight right now, though, so nothing big.
Just read through this entire thread for the first time. In the beginning I was getting excited for the dyno numbers and 1/4 mile runs I expected to be in the latter pages. Then once I saw the switch to the DOHC head I knew it wasn't done by page 14 lol.
Well, I've decided to sell everything and start a new project...On a 2013 Volkswagen Beetle!
Just kidding. Still slowly working on doing minor repairs to the car, and slowly forming a complete plan of action on the SD-4 DOHC. Still fine tuning designs on the intake/exhaust (billet header collector anyone?) here and there between finishing school (2 more semesters!) and working 80hrs/week. The Turbo Super Duty Build is far from forgotten and WILL be finished!
ive had this thread favorited back before I had my first car (fiero) im anxious to see just how much is actually possible with that engine. I understand the school and work situation, im still there myself. keep at it.
Where did you get your injector bungs for the 4 brrl intake ? Are you keeping all the 433 head/intake stuff ? Thanks Rick
I got the injector bungs from SDS EFI. I'm still planning on keeping the 433 stuff, as I just can't seem to bring myself to part with it. It's also there as a back up plan in case I hit a major(er) roadblock with the Cosworth head.
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Originally posted by Josh52894:
ive had this thread favorited back before I had my first car (fiero) im anxious to see just how much is actually possible with that engine. I understand the school and work situation, im still there myself. keep at it.
