WOO-HOO! Here it is Replace you clock with this...

[SCWDP911]

Originally Posted by GH85Carrera

Like most things it depends on price and performance. The volt / CHT gauge looks nice. Can the volt meter just read any 12 volt source or will it need a special feed from the charging system. Will the CHT gauge read the CHT from the fuel injection sensor without affecting the values the fuel injection? Where will the CHT gauge get the signal?

I would love to have a gauge like that but how will I hook it up and what will it cost?

+1. Nice work!

[marks914]

Here is the deal on the gauges:
They start life as a 911 fuel gauge and I take it apart, strip the trim rings, and face plate, then soak them in naval jelly to remove any rust (you wouldn't believe how rusty these get even when they look good), paint them with self etching primer, then 60% gloss black.
The insde of the can is sprayed flat white, or silver based on the core and an adapter plate is used to space the new gauges to the correct height.

I then install a VDO voltmeter, which can connect to the clock's original wiring and a VDO cylinder Head Temp gauge. The CHT is a spark plug lead unit with all the wiring and sender. The sender mounts under a spark plug, pretty easy install. Are there better CHT gauges out there? probably, but they are digital, and I wanted to make a gauge that looked factory, and VDO is a brand I trust, Porsche has for how many years? I basically buy these gauges, take them apart and install them in the new gauge.

The gauge nomenclature faces are vinyl printed with plastic, I have not seen one fade. They are adhesive backed. They do not come off, Whenever I screw one up, I have to sand it off.

The face plate is the stock piece that is printed with the correct call outs (volt, CHT) I have tools for horizontal, vertical and icons.

It is topped off with a new glass face if needed.

I can add LED warning lamps if you like as well, pretty much the same thing I do with the 914 quad gauges.

You not only get a gauge with more pertinant information, but you also get one that looks like it belongs there and is fully restored.

PRICING:
These are not cheap to make, a CHT gauge is $80-100, and a voltmeter another $30. Its about $150 in materials plus about 2.5 hrs in labor.
I am trying to keep the price at or below $250, and that would be with someone sending ma a core. I was going to try to get some cores, but the prices vary so wildly, it would be better for the customer to get the proper core for their car and send it to me. Why don't we say an introductory price of $250.

I can put any 90 degree sweep VDO gauge (and some others) in there, so if you have any more ideas, let me know. I am looking at a Norsdog air fuel mixture gauge, but its a 3 week lead time to get it.

Let me know what you think on the pricing, if anyone is willing. If its too much, then I will abandon the project because its what it takes to make them. I will be ready in about a week, I need to digitize a can and layout an adapter plate ion CAD so that I can get them water jet or laser cut.

I will also add them to my website in the follwing week, as soon as I am off of overtime at my day job.

Thanks for the feedback
Mark
I have had my work shown in Hot Rod magazine and I did the gauges, instrument panel, wheels, windshield and some other design work on the SR392 shown at SEMA this year, as well as the Dodge MX Warrior, Nitro Panel Wagon, the new 2009 Ram, 08 Dakota (new) and plenty of other stuff.

http://members.aol.com/bigmarkdesign/products

[GH85Carrera]

It would be interesting to find out what the real world normal range of a cylinder head in a 911 can be. I would GUESS that the temp close to the exhaust valve is much higher than the other side of the head. The CHT used for the fuel injection system is on the front side of the engine. Having a gauge is useless unless one knows what it is supposed to read. Maybe a sensor mounted in the exhaust manifold like the O2 sensor would be useful.

On an airplane the pilot monitors the exhaust temp to make sure the air fuel ratio is optimum. If the temp gets high the pilot can enrich the mixture with a knob. To reduce fuel consumption the pilot likes to keep the ratio lean but not to lean. We will not have that option on our cars, the computer takes car of that for us. About all that we can know is that under extreme conditions we should back off the throttle but the oil temp will tell us that as well.

The volt meter part is great but instead of a CHT sensor how about something else. All I can think of right now is a outside air temperature gauge. That would be a lot easier to hook up. What are your ideas?

[marks914]

Alot of the 914 and VW guys run a CHT,
The FI sensor is picking up a temperature at a different location and is calibrated for that
reading.
I have heard of many heads being wasted with oil temps being OK

Mark

[PatrickB]

Will the CHT only read one cylinder, or will you have a position switch that will choose which cylinder?

[marks914]

It will only read off of that cylinder. I know on type IV motors guys run it under the #3 plug because that one is the hottest. I think we would have to do some research to find out what plug would be ideal, I am sure someone here knows. I guess you could run 2 in one pod to get both sides.

Mark

[ischmitz]

Originally Posted by Jack Olsen

...I don't think I've ever seen temps higher than 325 degrees. Is it even possible to get 500+ degree readings, or would it make more sense to put in a gauge with a range more appropriate to our cars?

Jack, I guess it all depends on how well your mixture is controlled. With electronic fuel injection and a mostly stock engine you are much closer to ideal than say a carburated engine with improper jetting.... I wonder what others have seen.

[SCWDP911]

Mark, there is a thread on here somewhere where the hottest cylinder was researched, IIRC.

Also, I like your work on this, but what adding the voltmeter to the bottom of the tach. Cost estimate? I will post a pic in a minute when I find it...

[SCWDP911]

like this, but for an SC tach (for me anyway)...

[haycait911]

I'd certainly be willing at $250. but would like the CHT sensing nailed down. something that will work with carbed cars and not in conjunction with the FI. seems to me the carb guys are the ones who need this info more-so, due to the variables in jetting/set-up. Don.

(running a 2.7, a CHT gauge would ease my mind immensely)

[Trotskyite]

I already spend too much time worrying about my temp/pressure gauge. The last thing I need is to have more things to panic about.

[dd74]

Originally Posted by haycait911

I'd certainly be willing at $250. but would like the CHT sensing nailed down. something that will work with carbed cars and not in conjunction with the FI. seems to me the carb guys are the ones who need this info more-so, due to the variables in jetting/set-up. Don.

(running a 2.7, a CHT gauge would ease my mind immensely)

Me too. I'll start a new thread asking which plug is ideal for the CHT reading.

[marks914]

Originally Posted by haycait911

I'd certainly be willing at $250. but would like the CHT sensing nailed down. something that will work with carbed cars and not in conjunction with the FI. seems to me the carb guys are the ones who need this info more-so, due to the variables in jetting/set-up. Don.

(running a 2.7, a CHT gauge would ease my mind immensely)

This one is independant of the FI, it has nothing to do with it
Mark

[nyne11]

Originally Posted by v8_ranch

like this, but for an SC tach (for me anyway)...

+1 on the tacho....what sort on money are we looking at or that conversion.
Dave

[nyne11]

How about Volts and Vaccuum?

[marks914]

Originally Posted by nyne11

+1 on the tacho....what sort on money are we looking at or that conversion.
Dave

The turbo tach below is $250
A voltmeter would be a siminlr price, probably around $225. that includes a new face with any style redline, and anywhere you want, new modern guts for the tach, new glass if needed and refinished can and trim rings


Now that I look inside a tach again, I can fit a voltmeter with the stock guts, the price would be around $150
Mark

[Rick V]

Nice work, it looks like it should be there. This would be nice in my 71 when I get it finished.

[Tim Hancock]

FWIW guys, EGT (exhaust gas temp) is the most useful indicator of proper jetting. CHT (cylinder head temp) is more or less an indicator of proper cooling. EGT nearly instantly shows lean conditions at a given throttle setting, by the time the cylinder heats up to show on a CHT gauge, detonation could have already occured.

I use both a CHT and an EGT on my experimental airplane. The CHT is useful to tell me whether my fan cooled engine's cooling system is indeed working and not clogged with a mouse nest etc. The EGT shows me what my mixture is at any given throttle setting.

Marks gauge looks really nice and if I had one, I would simply consider the CHT function to be a safety indicator to warn me of a problem with my fan or an obstruction in my cooling shroud. Minor changes in CHT temp would not be worth noting, but if the CHT started climbing towards 500 degrees, I would know I have a problem.

If I truly wanted to monitor my mixture, I would get an EGT gauge (sending unit would need to be installed in the exhaust manifold near the cylinder), not a CHT.

Nice looking stuff Mark!

[Netspeed]

Originally Posted by Tim Hancock

FWIW guys, EGT (exhaust gas temp) is the most useful indicator of proper jetting. CHT (cylinder head temp) is more or less an indicator of proper cooling. EGT nearly instantly shows lean conditions at a given throttle setting, by the time the cylinder heats up to show on a CHT gauge, detonation could have already occured.

I use both a CHT and an EGT on my experimental airplane. The CHT is useful to tell me whether my fan cooled engine's cooling system is indeed working and not clogged with a mouse nest etc. The EGT shows me what my mixture is at any given throttle setting.

Marks gauge looks really nice and if I had one, I would simply consider the CHT function to be a safety indicator to warn me of a problem with my fan or an obstruction in my cooling shroud. Minor changes in CHT temp would not be worth noting, but if the CHT started climbing towards 500 degrees, I would know I have a problem.

If I truly wanted to monitor my mixture, I would get an EGT gauge (sending unit would need to be installed in the exhaust manifold near the cylinder), not a CHT.

Nice looking stuff Mark!

I was thinking the same thing about EGT. That would tell you about all the cylinders correct? The CHT would tell you only about one cylinder....what if the temps were high on the opposite bank?

Great work on the gauges though! Any chance of an EGT gauge?

[marks914]

I can put any 90 degree sweep VDO gauge in there, no problem, and some others,
Find a 90 degree sweep gauge yopu like, and let me know. I will see if I can make it work.

If you are looking to monitir A/F ratio, why not use a A/F mixture gauge?

Mark