I love the look of this car!
I love the look of this car!
Really enjoy my Speedhut gauges. They offer GPS speedos and you get to design them as you go. Such as: choice of bezels, needle color, font, etc... https://www.speedhut.com/
Had a bit of time to mess with the car this weekend before taking the wife to lunch in it on Sunday. Good news is that she’s coming around and starting to like the car. Especially now that I raised the passenger seat and she can see over the dash!
I took a look at the wires and gauges and it looks pretty straightforward after I spent some time in the trunk and engine bay. There is a spot on the HEI Supercoil that lists a spot for the “Tach.” For the speedo, Marshall recommends getting the gps converter and the other four aux gauges should be pretty straightforward with their sending units. Here is a rough before picture of the instrument cluster.
And I also spent about an hour fabricating a front grille just below the windshield.
The gauges I order stated that the tachometer requires a filter due to the high output of the Accel HEI Super Coil - Does anyone know if this "pigtail" would work?
Or do I need to order one of these?
It's been a little while. Spent a fair amount of time on the car this week. Got the tach and water temp gauges working. Will probably have to take it somewhere for the others as I'm at a loss, but it's turning out alright. Certainly what I've done will piss off some Porsche purists, but its an outlaw and its about driving.
Gauges are now hooked up and functioning! Big win. Feels much more comfortable driving the car being able to monitor how it is performing. I've run into a few issues though that I'd love help with if anyone has any ideas.
First, the prior owner had a Equus water temperature gauge hooked up and it consistently read between 170-180*. Now, the Marshall water temperature gauge is reading a steady 220*. I have changed nothing and the temp sender is in the same location. I just don't understand the significant change. I'd assume the Marshall gauge is more accurate as it was more expensive but decided to test the temperature with an infrared gun and was typically showing 20* lower when aimed at the location of the block where the sender is. Reference the below pictures taken within seconds of each other illustrating the 20* difference.
This afternoon I'm planning on pulling the sender and putting it in a pot of boiling water in order to see if the same difference exists, and if so, I'll ask Marshall to send me a replacement. Other than that, does anyone have any troubleshooting advice?
Secondly, the highest temperature I saw at any point in the block was 215* but the majority was around 150-160* when measured with the gun. What is a safe range for a ZZ4? I've heard a lot of variation.
Lastly, what other actions can I undertake besides potentially changing out the thermostat to lower the temperature if the gauge is in fact, accurate?
And anyone have a solid tutorial with pictures on tuning a Demon 625 street carb? I was able to tinker with it a bit yesterday and resolved an issue with the stuck open butterfly valve but the car has a bit of hesitation at times when I press the throttle.
Thanks!
Very cool project.
When The thermostat is open, it’s open, regardless of when it opens. So if it is a 180 thermostat and it is running at 220,it won’t make a difference if you change it to 160.
Now, if you completely remove it, that’s another story. Some will say don’t remove it because it causes backpressure that helps or that the coolant goes too fast through the radiator (which is bogus) but from experience, my old Chevy always ran at 110. I just thought the gauge was reading wrong. Until years later I pulled the water neck off for some reason and discovered it had no thermostat. Plugged a 180 one in and it ran at 180.
Besides that, a bigger radiator, proper ducting to force air through it, and big fans all will help.
But finding out what the temps do at idle, city and freeway driving can help determine what would be of more use
on a side note, did you get the gps speedo? I have run into them a few times and hate them. Losing signal, taking a long time (minutes usually, sometimes 5-10) to acquire the signal, sporadic readings..... I would do whatever it takes to get a mechanical/electrical one operating.
Lastly - super cool car
Thanks Octavius. Sweet Targa.
In reply to jfryjfry :
I'm assuming you meant 210* for your old Chevy? There is a distinct possibility it doesn't have a thermostat - It's obviously a bunch of random parts thrown together that works pretty well, but I could see that as being possible. I'll look into it tomorrow or Sunday (provided I can get away from the wife and 18 month old for an hour or so!)
I'll try and get it out on the street in the next week or so once I get the carburetor tuned properly so I can get some good references with the new gauges.
As for the GPS speedo, I've only driven six miles since installation but it found a signal immediately and functioned flawlessly for that short period. I was actually really impressed. I'll give you an update when I put some more miles on it.
Thanks, its got a long ways to go but even when frustrating, I'm having a good time along the way.
A few more images from this afternoon.
Sounds like a crossram DCOE style manifold could have solved your carb clearance problem ;)
Welcome!
If its an original demon, they were notorious for inconsistent running and drivability issues. I dont remember why, but NEVER met a satisfied customer with one.
As far as cooling issues: can you give us some overview of things like where/what radiator, hoses, fans, etc?
Also, the electrical water temp gauges operate by variable resistanceto ground on most. If its only got one wire at the sensor, it uses the threads for grounding to the engine, and the resistance from the threads to the gauge can screw up the readings significantly. So, cover how its wired, and we will se if we can help!
Try your temp gun on the radiator. You will never get an accurate read on water temp by pointing the temp gun at the block. I like a temp sender in the radiator hose going to the radiator. That will give you an accurate read on the water coming out of the block.
Air flow for a radiator in a Porsche is always a challenge since they were never designed for a front mounted radiator. Where is the radiator and how does the air get in and out of the front compartment?
Duster,
It's got a single wire going to the sender. I tested it with a multimeter about 30 minutes ago and I'm fairly certain the car is just running warmer than I'd prefer. The gauge manufacturer states that the sender will show 64 ohms at 220* and 110 ohms at 190*. I took two measurements once the car was at operating temperature and the first showed 85 ohms at 215* on the gauge. The second showed 93 ohms at about 208*.
Any way for me to tell if it is an original demon? I performed a cursory google search but couldn't find one.
As for the cooling fan, radiator, and hoses - That'll have to wait for another weekend. The previous owner(s) had it completed and it's actually quite difficult to get to in the front of the car. The entire assembly is contained in a fabricated metal box just aft of the opening in the front bumper. The radiator is not vertical however and is angled back at about 45* which probably doesn't aid the cooling issue. I'll definitely look into it and get back with that information as soon as I'm able though. Thank you!
Maj,
I'll do that the next time I'm able to unbutton her. And I've read horror stories. I thought I was just lucky that the previous owner(s) took the requisite measures, but it looks like the prior gauges were just not reading correctly. As for the location, like I said, it's contained in a fabricated metal box that is quite difficult to access. I can only see the radiator from under the front bumper and it doesn't really look like there is a way for the air to escape, but I haven't got deep into it because until the new gauges were installed I thought it was running within standard limits. The air comes in from the large opening in the front bumper.
Could it be an air pocket? With a front mounted radiator, id have to assume some interesting routingof hoses.
The original demons were generally holley shaped, rounded corners on tge float bowls with demon cast in.
If its easy, take a picture and we'll see if wr can figure out what you got.
And that sounds plausible fir resistance readings.
Duster,
It is certainly possible. I suppose I could park the car on a significant decline, or lift the rear of the car and try to "burp it." Couldn't hurt.
If you look at the above picture of the side view of the car you can see one of the coolant hoses below the body of the car - It has a very nice white overspray to accentuate it. 
These are what I have on my phone handy regarding the carb.
I have also noticed that the fuel pressure upon cold start is solid at around 5.5, but once warmed up and at full operating temperature it drops to about 3 which is below ideal from what I've been researching.
That is an original demon!
And should be a steady 6.5 if i remember correctly for fuel pressure on those.
Ben_Modified said:This hat from a late model cadillac. $9 at the pick a part. It can oriented in nearly any position. K&N generic filter and aluminum tubing.
20180912_174010_resized by Ben Modified, on Flickr" />
I need something like that for a build I'm working on. Any more detail on year and model of Cadillac with that setup?
loumash said:Ben_Modified said:This hat from a late model cadillac. $9 at the pick a part. It can oriented in nearly any position. K&N generic filter and aluminum tubing.
I need something like that for a build I'm working on. Any more detail on year and model of Cadillac with that setup?
No, sorry. I just walked around the pick a part until I found a good one. Jeep has something similar but it looked like it would be very restrictive.
Ben_Modified said:loumash said:Ben_Modified said:This hat from a late model cadillac. $9 at the pick a part. It can oriented in nearly any position. K&N generic filter and aluminum tubing.
I need something like that for a build I'm working on. Any more detail on year and model of Cadillac with that setup?
No, sorry. I just walked around the pick a part until I found a good one. Jeep has something similar but it looked like it would be very restrictive.
That looks Pre-Northstar, like something off of a late 80's early 90's HT4100/4500. Think like 88-93 DeVille, Eldorado, Fleetwood, etc.
Dusterbd13-michael said:That is an original demon!
And should be a steady 6.5 if i remember correctly for fuel pressure on those.
It is, it is actually a Barry Grant Speed Demon after I located the parts number. The good news is that at about 85* today the car was idling steady at 200-205* after tinkering with the carburetor a bit. I went here to look at tuning.
Now the car starts perfectly and idles just fine. Unfortunately there is significant hesitation/stumble under throttle application. I attempted to adjust the secondaries as depicted on page 13 and 14 of that PDF but my Speed Demon carb doesn't have that unfortunately.
Here is a question, could the low fuel pressure be causing the hesitation and warmer than typical fuel temperatures? The carb states it requires 6-7.5psi to run properly. I dug into the car and saw that there is a Holley 125 fuel pump in there but couldn't locate a regulator anywhere. I'm going to run to the store and try to install one and see if that gets anywhere.
I'm still working at getting to the radiator, just give me a bit of time!
Thanks again everyone.
Low fuel pressure can lead to lean spikes or stumbles, do you have a wideband o2 on the car anywhere?
Sean
How is the accelerator pump?
As light as that car is you could check the primary squirter, it might be too big for a change. You'll have to buy an assortment close to the number thats in there and start swapping them out. Maybe get someone to follow you and look for black smoke, good luck!
Quick update - I spent a number of hours teaching myself about carburetors the past two weeks via Youtube and other online resources. Bottom line, I think that the fuel floats were too high. I lowered them to the lowest mark in the sight window per a Speed Demon setup tutorial I found from 15 years ago and the fuel pressure shot up 3psi to a solid 6-7psi. That helped significantly. Car starts instantly and has almost no hesitation. I'm still going to tinker with it once this storm passes but I drove it for a while today and was very happy by the change that resulted from simply lowering the fuel floats.
Now, I still have yet to get to the cooling issue but I haven't seen above 205* the past few drives which is promising. That being said, I'm going to pull off the bumper and provide some images for a consensus on how I might better cool the entire system here in the near future. I do know of a member on Pelicanparts who runs a similar setup to mine with a 434ci SBC and he runs an oil cooler in addition to what is essentially my setup to keep temps in check. Anyone have any personal knowledge as to the effectiveness of that approach with keeping a small block cool?
Hope everyone enjoyed their holiday weekend last week. I'll be back with an update when I have one!
Done a bit of work recently, not nearly enough. But I Raptor lined the interior and started making a carpet kit to make it a bit more comfortable. Still not happy with the carburetor and thinking about either going EFI or just going to an LS engine once I move to San Diego this summer.
Fortunately got my two ladies to lend a hand!
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