Gauge Tech Question

[455Rocket]

Alright guys...
I replaced my orginal SW gauges w/ some VDO units... All work except the temp gauge. The gauge doesn't want to climb above 100 degrees, but I know I'm running around 180 normally by the old gauge
Wiring is ok b/c the gauge is showing SOMETHING (Just re-wired w/ #12 wire etc... so no probs w/ that)
A few years ago I remember the engine rebuilder asking me what kind of gauges I had to get a correct replacement sending unit... SO I figure I need another sending unit to match the new gauges.
Do you concur? Any experence w/ this problem?

[YeLLowBoaT]

that would be my guess as well.

[Oldsquirt]

You definitely MUST match the gauge to the sender. Just get the correct VDO sender for that gauge.

[455Rocket]

I'm blindly guessing Rex Marine... but that's my answer for most everything.
Where oh' where shall I go for said unit?
P.S. I don't know where else to go for such quick info... Thanks ya' all

[Rexone]

Let me know what the VDO gauge number is (or at least the exact temperature range) and I might have a sender for it. VDO discontinued most their marine series stuff a few years back so we no longer carry but I do have some misc senders and stuff left.

[SmokinLowriderSS]

Don't know if this'll apply or not, but, when I put my new digital gauges in, it said to NOT USE any thread sealant on the senders as it could alter the grounding path conductivity and make the gauge mis-read. Just a thought.

[455Rocket]

Let me know what the VDO gauge number is (or at least the exact temperature range) and I might have a sender for it. VDO discontinued most their marine series stuff a few years back so we no longer carry but I do have some misc senders and stuff left.
Temp. Range is 100 to 250 degrees:
The gauge is the standard VDO marine issue... black face, white letters, blue lines... I know Carrera used the series I have as standard issue in the early 90's - As im sure many others did
Sender looks like it needs a 3/4" NPT hole... it's sitting in a Eldelbrock Torker... so there could be other hole size options i'm not famillar with at this point.
Any help would be appreciated!

[455Rocket]

Don't know if this'll apply or not, but, when I put my new digital gauges in, it said to NOT USE any thread sealant on the senders as it could alter the grounding path conductivity and make the gauge mis-read. Just a thought.
Point well taken... but the sender worked fine w/ the old gauge a month ago... I used sealant on the #2 and #3 threads only

[SmokinLowriderSS]

Point well taken... but the sender worked fine w/ the old gauge a month ago... I used sealant on the #2 and #3 threads only
Sounds like a miss-match, time for a new sender. :idea:

[Oldsquirt]

Point well taken... but the sender worked fine w/ the old gauge a month ago... I used sealant on the #2 and #3 threads only
Not all manufacturers use the same resistance profile for their gauges/senders. What worked with the old may not be correct for the new. It is always a good idea to buy them as matched sets.
You should really NEVER use sealant on a sending unit that uses its body as a ground path to the engine. Not likely to be your problem in this case but it can cause excessive resistance in the circuit, leading to gauge inaccuracy.

[Moneypitt]

Sender looks like it needs a 3/4" NPT hole... it's sitting in a Eldelbrock Torker... so there could be other hole size options i'm not famillar with at this point.
[/QUOTE]
What ever the thread in the manifold is, 1/2 NPT more likely than 3/4 NPT, you will have to bush it down to the sender thread if not a match. 1/2 NPT is common for temp senders, and BBC manifold heater and by pass hose conections...MP

[455Rocket]

[/QUOTE]What ever the thread in the manifold is, 1/2 NPT more likely than 3/4 NPT, you will have to bush it down to the sender thread if not a match. 1/2 NPT is common for temp senders, and BBC manifold heater and by pass hose conections...MP[/QUOTE]
Right you are... 1/2 not 3/4.. DUH!

[Nubbs]

Shoot me a pm if you need assistance figuring out the resistance needed for your gauge. I had a mismatched sending unit give me problems once too.

[Rexone]

See your PM's I sent you the part numbers for the 250º gauge.

[455Rocket]

Thanks for the help guys...
I'll drop a line if I have problems Nubbs.

[455Rocket]

Problem solved:
Jegs (http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?lang=-1&catalogId=10002&storeId=10001&categoryId=23849&searchItemId=41855&CT=999)