Projects Track Roadster 16 yrs in the making

ex,

I agree, center the throttle plates as best you can on a cold engine, and then hope for the best. I note that my newer Dodge Hilborns have thicker aluminum throttle plates compared to my old vintage DeSoto Hilborns. The DeSotos plates are steel and much thinner. In both cases the shafts are slit and the plates are gripped on both sides by the throttle rod.

I’m not sure I understand your suggestion regarding the throttle return springs. One of the springs on my Hemi you can see in lots of the photos, it pulls on a throttle arm between the #6 and #8 (cylinder) stacks [see page #41, Post #801]. The other spring is not visible in the photos. It pulls on a throttle arm at the front of the driver’s side throttle rod. So one lever arm is toward the rear of the passenger-side rod and one spring is on the front of the driver’s side rod. The passenger side throttle rod is actuated by a crossover linkage rod that passes from the driver’s side to the passenger side — this occurs between the third stack back and the last (4th) stack. [see page #41, Post #801]

Dick Easterwood, a KC hot rod and sprint car guru, says that all the pull should be from right in the middle of both rods, via a bellcrank; but Brett and I have bigger problems that that right now. Maybe we should chat via phone.

The alternator (rectifier circuit board) caught fire and the alternator is destroyed. We are scrambling to find a higher capacity unit, AT IDLE, and hope it can, somehow, be shoehorned into the same tight spot as the failed (and smaller) alternator. Keep your fingers crossed. We may have to carve on the cast iron head castings....!

Keep up the suggestions and observations.

charlie

 

I'm not an EFI expert. Not at all.

But looking at your system from an operational and reliability point of view. I think that Rex's balance plenum is very good. If it was a mechanical system it would still work to balance out the vacumn. Not just the vac signal that the computer is reading. I'd bet that there is air flow thru that system at idle and helps each cylinder get it's fair share of air. Throttle plates alone can't be that precise at almost closed position and heat expansion of the bores really screws around with the airflow at closed throttle. And this is true on EFI and Mechanicals.

Your system with the small bleed tubes going to a plenum should still do the same thing as Rex's (balancing). It does not take much air to have one cylinder idling. The size of the plenum is not as important as the connecting tubing being able of even out the flow and overcome the variety in the throttle plates and bores.


Without going back in the tread to double check, I'm going to guess you are using 3/16 tube and fittings. I do remember you saying that you used the former fuel discharge holes for the vac system, right?

Good luck. Charlie, you're getting there!

Frank

 

Charlie,
Regarding the small plenum that my vacuum lines run to, it is important to have some volume but again to large and the signal to the ECU and fuel regulator gets very sluggish, i.e. you have added capacitance which slows the signal down, however a very small volume plenum and the signal can be very erratic but because you have an 8 cylinder I would think it would not be as critical as a 4 cylinder. One thing about your vacuum setup is that you are using 3/16 tubing which can act as a dampener to an erratic signal. If you get down the road and decide that you might want more volume simply adding a short piece of 3/8 hose that is plugged on one end and connected to your collection manifold may add sufficient volume to make a difference.

Regarding your alternator,you must have a good charge to the battery, 12 Volts+ and also you need to make sure that everything has got a good direct ground directly back to the battery, including the engine block. Bad grounds are one of the biggest problems with this kind of thing. Looks like you are hammering away on it, I know you will get it going.

Rex

 

Got it. What I don't see is how the pedal actually operates the throttle plates in the first place. Sorry if you covered that elsewhere. My original point was; since the linkage is all solid and the shafts are one piece, you can mount the return spring(s) to the actual lever that pulls the throttle open. That way there is no torsion force along the length of the shafts.

Don't get me wrong, it may not even BE an issue; but I've had this exact problem on my race engine, and wanted you to be aware of it.

 

Early,

The engine in my TR is a 1975 Dodge KD500. It does not have adju. rockers. I am pretty sure all the 1x4bbl, 1957 KD-500 blocks, came with hydraulic lifers, and non-adju. rockers; however, it may be that the 2x4bbl engines had adju. rockers and solid lifters. Even though the 1x4bbl KD500s had hydraulic cams the passenger cars were equipped with the “bubble” valve covers.

My 1956 Dodge 4dr Ht had adju rockers, until a common thief stole them while “rebuilding” my engine years ago. I asked for the thief to replace the solid lifter cam with a KD500 hydraulic cam. It never occurred to me to check and see if I still had the correct lifters when I got the car back.

Oh well.

Keep your Hemi runnin’

charlie

 

Ex,

OK understand your point. The upper arrow points to the “top”of a lever arm that is almost vertical to the image plane (pointing at the viewer), this is one arm of a bellcrank. There is a cable attached to that lever arm (arrow). The spring, which is not visible in this photo, is attached to the second arm of the throttle arm bellcrank, and is hidden from view by the “valley cover”.

OH I agree all this could be a problem, especially if I have to use overly strong springs to “return” the throttle plates — which are never completely concentric with the stack bores (as we have been discussing). Indeed the presence of the big spring you can see in the photo is a “add-on” that was needed when we began running the engine in the real world, and the heat started to warp and move the shaft, stacks and throttle plates around. Kind of a vicious circle. This last issue is probably the best argument for having the shafts bushed/sealed and coupling installed....

I have found that every time I run the Hemi it is useful to put a tiny drop of high quality silicone lubricant (from a fine bore needle) at each throttle rod boss. The throttle shafts move more freely for a few engine hours.

Stay with us on this.

charlie

 

Bill,

Great story.

Right you are. It is phenomenally easy to over rev the Hemi; especially with the low first gear ratio in the 5 speed.

That is why I asked Brett to install a 5000rpm rev limiter chip in the brand new Accel engine management system. I figure that the rods will last my lifetime if I keep the revs under 5 grand.

charlie

 

I have a question. Whats the deal with the fuel distribution block? Are those fuel lines and nozzles actually plumbed into the plenum? Or are you sourcing your vaccuum signal from them.

 

deto,

The plenum you see on “top” of the valley plate is a phoney ”fuel block” with phoney “fuel” lines that are plumbed to the original Hilborn fuel inlet bungs. In my EFI system they are, as you suggest, a source of a vacuum signal.

If you go back a few pages in the thread you can see the whole enchilada, layer-by-layer, and the electronic nozzles that are hidden by the valley plate.

charlie

 

ok. So this alone isnt enough to provide a common plenum between the runners?

 

deto,

Yes in my estimation it is a common plenum. From a physics standpoint the "fuel block" and all the hoses are part of a common plenum. If you were an oxygen molecule you could "go" anywhere in the system, there are no blockades. Of course it is not likely that there is very much "flow" in the system. My guess, based on no data, is that the vacuum pressure (manifold absolute pressure) is vibrating slightly with the pulsations of the cylinders, but the cavity in the "fuel block" kind of acts like a dampener. The relatively small caliber of the hoses also likely dampens the vacuum oscillations.

We hope that the resulting 12-14 inches of Hg will provide sufficient vacuum signal for the CPU to do its magic. I am beginning to think this all might work out in the end.

Charlie

 

Charlie,
Your sprint car buddy is correct. Ideally, the pull linkage and crossover should run between the 2nd and 3rd stacks. That gives you the minimum number of butterflies to either side of the linkage. ...You are also correct in thinking that would be difficult to pull off on the Maserodi.

I'm in the same boat with my old Crower manifold. The center bridge of the casting is so close to the throttle shafts that there is no room to put the linkage through the center. Mine pulls off the front, as yours does. The original shafts were necked down where they passed through the casting and used nylon wraps as bushings. So far the new bushings and straight shafts have kept it healthy, only time will tell.

Just had a thought...gotta go back and re-read something you posted a few pages back.

OK, you had mentioned that the #1 and 2 cylinders were particularly colder (EGT) at idle than 5 and 6. Where are the idle stop screws located? I'm assuming #1 and #8?

 

The linkage is probably not going to change too much right away. The idle stop screws are now at the rear of both shafts (one each).

Maybe I’ll get the engine running OK and slowly improve the various deficiencies in the next year or so.

charlie

 

Rex,

Sorry for the slow response. Work is interfering with my hot rod life.

Your idea to add volume with a lenght of hose is brilliant; simple and effective. I would not have thought of that.

Unfortunately as of last night I am in deep doodoo regarding alternator options. A larger capacity Powermaster alternator will not fit in the present space. The old unit and the one we tried last night are based on Denso alternators. They have the same mounting hard points but the higher idle capacity unit is a bit longer (.42”) and perhaps an inch larger diameter. The big unit will almost fit in the old position but no chance of any “swing” to allow for tightening the drive belt.

We think we need about 40 amps at idle to be comfortable, and the unit we tried last night produces 85 amps at idle. The unit that failed is the next size down for Powermaster at about 25 amps at idle. So right now Brett is going to check if there are any other options.

Everyone reading this will be thinking why not move the alternator away from the block and gain some room? The answer is pulley position. At this time the front pulley is ¼ inch away from the frontmost frame cross member, and that is not an exaggeration. So if I want to remount the larger alternator about one-half inch forward, where it will fit and have swing space, I will have to have the front cross member cut out and repositioned as well as a hydraulic brake line. Notching is not an option, believe me. To accomplish re-fabricating the cross member will require removing the nose and radiator, not a trivial undertaking. The task will have to be done at a real fabrication shop, not in my home garage.

As you might expect this was not good news. I leave tomorrow for a three week trip so I will have time to let the frustration taper off. But for right now there will be no tuning of the EFI for at least four weeks, assuming we can find an alternative to cutting up the front cross member. Otherwise I’ll probably ask Dick Easterwood, over in Raytown MO, if he will do the surgery on the TR.

Charlie

 

Pics, please, of engine area as it sits w/o alternator in place. Maybe the HAMB can come up with an idea.

Would a pulley, u-joint, small dia. shaft (like a steering shaft), ujoint, remote alternator idea work?

 

Awwe, Fuck me runnin' . That sucks Charlie.

I'm sure there's pics in these 43 pages.

 

Built,

I’ll try to post a photo, but I’m trying to tie up things for my flight tomorrow.

Since we need lots of juice at idle, the remote location is a non-starter. I think that if I have to go to heroic measures I will have the front cross-member refabricated; because that will also cure a worry I have about the crank pulley being way too close to the crossmember. I already have some butt ugly cargo straps in the undercarrage that “locate” the drivetrain and prevent the motor from moving foward during a hard stop.

So the major surgery would cure two deficiencies — alternator space and crank pulley clearance.

Thanks for the kind thoughts,

charlie

 

31Vicky,

I appreciate your concern, but this problem, too, will get ironed out. It is more a case of this being such a long process. Perhaps three weeks of no TR anxiety will be a good thing. I plan to chill.

Best regards,

charlie

 

Would an idler with adjustment opposite the alt help avoid surgery?
This one is off of 55 354 but I have it on a 58 392 just for my run test stand.

 

I would have to look and rub my chin a bit. But I think that the passenger side frame rail would interfere; however, your suggestion is worth thinking about.

Thanks,

charlie

 

Could you have the smaller one rebuilt by an independent shop to put out more juice for you? There's a place in downtown KC, but the name slips my mind.

Chris

 

Hunt electric on the Blvd.

 

I'll give them a call. I talked to a couple of tech guys and they are going "see what they can do".

Thanks guys,

charlie

 

Your best bet is to talk to them "face to face".......I have had the 'shop kid' on the phone with HUNT & I finally had to drive down there.

Chris

 

Chris,

Your are right. I called Hunt, and the boss said bring the failed alternator to his shop and we'll talk about what might be possible.

This new wrinkle will move a bit slow as I'm traveling pretty steadily for about a week, part of the time I'll not be in contact with the modern world. Hooray!

Thanks for your concern,
charlie

 

[]~=====~[ALT]

I don't know if you have room for this at all (& it might be too ugly!) , but what I meant was keeping the pulley where it is in the current location, but the pulley is not connected to the alt. Instead the pulley drives a shaft with u-joints, which then drives the alternator. Thus the alt could be in a somewhat remote location,and the pulley diameter / alternator speed at idle are up to you. Alt could be back by the firewall or off to the side a bit, within reason.

Truthfully this is probably a bad idea but I'm hoping other people have better ones, mostly trying to just do some brainstorming.

 

Turn the alternator around, with the pulley facing rearward............I don't think it cares which direction it spins, with the exception of cooling fan discharge.

 

Ummm, he said the pulley was about to hit a crossmember. I'm pretty sure the body of the alternator is bigger than the pulley; so if it won't fit frontward, how is flipping it around going to give it more space?

 

Built,

You're a good guy for spending your time on my problems, thanks. The bad news about my track roadster is there isn't much room in the nose, especially side to side.

I honestly don't think a remote mounting will work. I appreciate your thoughtful comments

stealthcruiser,
Hummm, well I hadn't thought of that. I guess the struts securing the alternator would have to be seriously beefy...as ultimately the unit has to be affixed to the engine.

Ex,

You guys are great. The alternator pulley is way small, about 2.5' in diameter. The crank pulley is about 8 inches so the pulley ratio is about 3.55 to 1. My first thought to you and stealthcruiser is that the structure securing the alternator would be fairly massive. I'll go out and look at the location with your idea in mind.

Thanks for all the kind thoughts and interest guys.

charlie

 

OK, I just took a look at the area in question. There is indeed quite a bit of space directly forward of the present alternator position. Eventually the plastic electric radiator fan housing interferes.

Based on a two minute appraisal: there would have to be a pretty elaborate triangulated alternator support. Further, the present crank pulley would go in the trash and a new pulley offset toward the harmonic dampener would have be be built from scratch (the hub could be saved). I'll ask Brett to stop by and give this idea some thought.

I guess one consideration would be whether it would be possible to mount the larger alternator (high idle output), and would all this cost more, or less, than redoing the front crossmember?

By the way, just to be clear, the pulley that is interfering with the front cross member is the crankshaft pulley.

Thanks again guys,

charlie