69MyWay

iTrader: (2)

I am putting a LS2 in a 1985 Corvette and trying to re-use the digital Atari dash. Therefore, I have to keep all the original sensors (water temp, oil temp, oil pressure) - and of course work out the signal on the tach and speed.

HOWEVER, my water temp sender is much larger than the hole in the head.

Can I drill and tap that out to a PIPE plug in the large diameter?????

the_merv

iTrader: (88)

Wire in a second one..find it in the Harness, splice into the Ground side of the Sensor, and run that to the second Sensor. Then run the Signal side to the Gauge.

69MyWay

iTrader: (2)

the_merv - I don't quite understand.

The stock 85 sensor is a single blade terminal.

Are you saying to use the single twin blade LS2 sensor for both the LS2 PCM and wire it to the gauge?

daniel6718

iTrader: (36)

no if its only a 1 wire sensor then you need to put it into the head or something to ground it out...

the_merv

iTrader: (88)

What I was saying was to use a LSX Temp Sensor, and wire it in. You will still have the one going to the Computer on the Drivers side Head like a LS1 if I am not mistaken, a Friend of mine had a LS2 Corvette and his is setup the same way as a LS1. You need that Sensor that is in the Drivers side Head, so you are still at a placement issue regardless.
You can go with your Sensor or use another LSX Sensor, that is what I was talking about, but you still have to keep the one in the Head that is there already.

69MyWay

iTrader: (2)

Okay, I'm cool with that. That comes back to my original question; can I drill out and TAP the LS2 head to accept the large pipe thread of the 1985 Vette sensor in the other head?

I moved the LS2 sensor from the left head to the right head (will extend the harness), that leaves the driver head which is much easier to access (a/c box covers the passenger port) - to modify, etc. to get this to work.

I would guess I could drill, tap - vacuum the snot out of it, then screw in the 1985 temp sender. It is about an 1/8" larger around than the metric hole that comes in the LS head.

bczee

iTrader: (12)

You have two other location that you can use to add a second sensor.

1) Rear of the Passenger side head, They market adapter if you need them ( 10mm to NPT). I drilled and taped mine to 1/4" NPT, I think you can go larger if needed but it will be close to the ex manifold flange. What size is your 85 vette sender ?

2) Top of the Water pump, on the flat area. Just drill and tap too the correct size threads as your sender is.

69MyWay

iTrader: (2)

It is the second largest NPT size that you would run into on a Gen 1 small block. The adapter doesn't do me any good as those go from 10mm down, and my sender is larger than 10mm.

I have some spare LS1 heads that I thought I would try to drill and tap, I just hadn't remembered if anybody here had talked about doing that before. If you go with autometers or other a/f gauge, they have like 1/8" npt senders that you simply adapt down. In my case I have to go larger than the hole on the head.

the_merv

iTrader: (88)

Put that Sensor back to the Drivers side head, trust me..
You will get a mis-reading, and it will cause all kinds of hell on everything. That one Sensor has a part in ALOT of major things..
The reason I say that is cause that back side of the Head gets real hot, and it will tell the Engine that it's hotter than it actually is.

As far as locations.. have any of you done it in the Water Pump, and have pics of it? I didn't think there was enough metal there for it to get a bite into.

G-Body

iTrader: (4)

I don`t know how much different the LS2 heads are compared to 98 LS1 heads, but back when John B. did his first LS1 swap into his monte carlo he drilled and tapped the passengers side head to a 3/8" NPT for the factory monte sender.

the_merv

iTrader: (88)

Did it get hot back there.. Daniel was sayin when he tried it, it got pretty toasty back there..

G-Body

iTrader: (4)

I assume that John B. didn`t have any problems with it. I turned down my sensor in a lathe and stuck it in the back of the pass head and it seems to read just fine. I have a stock T stat and the gauge always reads between 190 and 210 at operating temp.

bczee

iTrader: (12)

IMO, I would think that the sensor and good wires/connector should be able to handle the heat.. if it was me, I would want to know how hot the engine is running and if it was the problem area that seem to be running hot.. that would be good info for me to know...

I have a VDO sensor and wire running back there and it is very close to the firewall and AC/heater box, the Gauge seem to be about right and the engine never gets above 200-205 (that is about where I have the SPAL controller kick in the fans into High) but usually around 185-195 most of the time.

I recall that I have seen picture of the temp sender in the Water Pump, but have not been able to find any in the searches that i have did.

the_merv

iTrader: (88)

I put my second one in-line on the hot side of the Heater Core Lines, I will see how that works. If no go with that, then it's goin in the passengers side Head.

69MyWay

iTrader: (2)

How would the same head flipped to the passenger side with the sensor there read any different than in the other position? Or, is it just the fact there is less airflow back there as the engine is that much further away from the cooling fan action?


I saw a thread where the water pump is being drilled and taped for a nipple to bleed off the head steam pipe. There isn't much meat to that pump housing, but it looks like it would work. I know they sell in-line pipe at Summit that you can screw a fitting into. That is an option with no mods to the engine. I already used a 92-96 Corvette in-line upper radiator hose T to run my steam line - I hate to add another splice to there too - plus it would require a ground to be run since it is a one wire.

bczee

iTrader: (12)

69MyWay...

Being a C4 Vette, I wouldn't worry about heat at that spot in your engine bay.. if memory recalls, it is pertty open there (as compare to many other cars) and should not trap very much heat. Just Drill and Tap it, If it doesn't work out, you can alway plug it and them move on to plan B.

I have mine taped to 1/4", but I have seen pictures on the forum with the next size (3/8" NPT) it just gets real close to the Exh Flange. Just use high grade wire and connectors that that can take the heat and you should be ok.

But almost every Hybrid (that does not including the 4 gen F-Body guys) have mostly used the rear passenger side as there Temp Sensor location.

ls1canuck

Do some searching on the internet. I would be very suprised if someone somewhere doesn't make an adapter to go from 12mm on the passanger side head to whatever size you need, whether your going bigger or smaller. I have a place here where I live that has never failed to get any adapter I've needed. Sometimes its taken a few days to have something shipped in, but I always get it. I would definately try this first before you go drilling and tapping. I always try to do things the easiest way possible.

Scooter70

iTrader: (1)

Chris,
I put my stock temp sensor in the passenger head. I drilled and tapped it just as you described. If you're careful and use some vasaline you should be able to keep the aluminum chips out of the head.

daniel6718

iTrader: (36)

i did it in the passenger head and it read hot...did it with a 98 sensor in the drivers heat and it still read hot, but the pcm reads fine...

back when i had the 99 sensor in there and the stock gauge T into it, it read 185 just right...but it screws ip the pcm...

69MyWay

iTrader: (2)

Cool.

I picked up a tap today, but nobody has a 37/64 drill bit in stock as of yet. Have to do some more looking.