stupid Small block questions

[dd113]

I will be the first to admit I dont like SBC in LCs. Especially in 40 series. Be that as it may I need to work on a 75 with a brand new 350SBC. RUns great. How do I get the Oil pressure and temp sender to read correctly on the gauges? Bothe read currently but I doubt if they are correct.

 

[ranger]

What gauges, are they factory or after market??? Electrical or mechanical?

 

[KNUCKLEDRAGGER]

Both Downey and A/A make adaptors to use the L C Temp and oil sending unit in the chevy motor attached to the stock gauge.

temp adapter p/n 15609

oil adapter p/n 8720F

They also say that on some late modle chevy motors the temp sensor will screw into the stock chevy hole and to "check your application"

hope that helps

 

[dd113]

Gauges are stock 2/75.All read correctly or at least indicate. I want to know if there is an adaptor or switch over that will allow the senders to read correctly on the stock LC 75 gauge.

 

[Sparky_Mark]

ddd,
The answer to your question requires you to get your hands on specific information for the sensors. You mention "new" Small Block Chevy - is it a crate motor, or a new engine yanked out of a newer running vehicle (reason I ask is that the new Small Block engine that replaced the 350 is the Gen III 5.3L powertrain)? Do you have a 5.7L or a 5.3L? If it is a 5.3L, and you can read the engine part number (rear side of the block on or near the head, an 8 digit part number), then I may be able to locate a drawing for the sensors (I work with GM in the Detroit area).
You need to know the resistance vs. temperature (or oil pressure) curve before you can consider your options. Then you can compare that curve to the points indicated in the Land Cruiser service manual. That comparison will allow you to calculate what you have to do to get the gages to read correctly.
I had a similar issue with my fuel tank. I got a long range tank that came with an Autometer sender. I got the curve and compared it to what the gage needs to "see" and did a few calculations to correct my issue. As it turned out, I added a resistor across the gage and it read most accurately near "empty".
You may have a difficult time converting if the relationship is not linear. Then you get into more exotic solutions that you probably won't be interested in spending the time to mess with (using solid state electrical components).
First things first, can you get the sensor information?

 

[dd113]

You are staritng to lose me on this already. I can get the block number tomorrow and post it here. it does not need to be dead on but I would like it to be in the correct range. Thanx for the help I will post the numbers here tomorrow PM

 

[Sparky_Mark]

Without knowing "the curve", you won't have a clue as to how accurate it is at any temperature (there are many temperature sensors - there is not a standard).

You may find several 8 digit part numbers all over the engine (GM puts their part numbers on every part nowadays). If you have a 5.3L ,the one you're looking for is on the drivers side, on or just below the head. There may be an easier way for you to investigate this yourself (at least for the temp sensor)...

If you remove the temp sensor and connect it to a multimeter (set to ohms). You can take it to the kitchen and get the curve by experiment. Take a pot and fill it with water, hold (not with your hands) the sensor in it and record the resistance as the water heats up - you'll need a cooking thermometer (don't let the connections get wet). This way, you get an approximate curve by experiment. Then you can compare it to what's in the service manual so you have an idea how far you're off.

 

[Texican]

If you adapt the Toyota senders to the GM block they will read correct
I've done a bunch, and with the GM TBI you can use a scan tool to double check them.....

 

[Gumby]

How are you liking that TBI, Butch?

 

[Texican]

[quote author=Gumby link=board=1;threadid=6865;start=msg57190#msg57190 date=1067566037]
How are you liking that TBI, Butch?
[/quote]


Once I got it dialed in, it rocks....

Butch

 

[dd113]

Ok, how then do I adapt the OEM gauges to the GM senders?

 

[hammerhead]

[quote author=knuckledragger link=board=1;threadid=6865;start=msg56434#msg56434 date=1067408979]
Both Downey and A/A make adaptors to use the L C Temp and oil sending unit in the chevy motor attached to the stock gauge.

temp adapter p/n 15609

oil adapter p/n 8720F

They also say that on some late modle chevy motors the temp sensor will screw into the stock chevy hole and to "check your application"

hope that helps
[/quote]
8)

 

[theo]

[quote author=dd113 link=board=1;threadid=6865;start=msg57243#msg57243 date=1067574976]
Ok, how then do I adapt the OEM gauges to the GM senders?
[/quote]

Well, I thought Sparky had you lined out on that option?? Sounds like you need to test the resistance at various temperatures and adjust it according to how far off the gauge is. The rest of us (well, I've been lurking) are talking about OEM sending units.

 

[dd113]

Theo, there are 2 things going on here One option is to adjust the curve of the stock gauges to match the GM senders, the other is to get adaptors for the stock senders to theGM block and keep the system the same.

My question, that you quoted, was where to get the adaptors.

 

[Texican]

Advance adapters sells them and if I remember they are not that pricey.
Butch