CRG Discussion Forum

Camaro Research Group Discussion => General Discussion => Topic started by: aaronz28 on April 27, 2015, 04:04:52 PM

Title: modded temp gauge for smaller sending unit anyone?????
Post by: aaronz28 on April 27, 2015, 04:04:52 PM
I guess this topic comes up often -  but anyone who has later model, or aftermarket heads combined with factory guages is going o run into the temp sending unit problem...

the best solution i've yet read is to use a TS76 sending unit, and then replace the resistor on the gauge with a 150ohm resistor...

anyone done this?  how accurate?   is there another solution to keeping the sending unit in the head (do not want to go 68 style as my car is a 69 and has the harness with the shorter length)

just curious.

thanks

A
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: BULLITT65 on April 27, 2015, 04:52:11 PM
I'm a little confused by your question. You have after market heads with a different location for sending unit?
(I have after market heads on a different small block but the sending unit boss is in the same place)
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: aaronz28 on April 27, 2015, 05:02:58 PM
sorry - no the location is correct (between the 1-3 exhaust port -  but it has the smaller tapped hole and will not fit the OE sending unit.

I could opt to put the sending unit in the intake like a 68 car, or get a thermostat housing with the larger port -  but I have a set of Dart heads that were milled by Brzenski on the ends to look like a set of 69-70 Z28 heads -   BUT the temp sending unit thread is smaller on the Dart heads.

thanks
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: BULLITT65 on April 27, 2015, 05:15:09 PM
Well I guess my initial thoughts if I put myself in your shoes: Since you went through time of making it look like stock heads on the ends, could you go the extra mile, and machine and retap the small hole(s) to take the stock sending unit?

If not, those original senders are brass, I am not sure how much it would affect the temp gauge if you just milled down the brass sender to fit into the smaller hole.
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: aaronz28 on April 27, 2015, 05:26:47 PM
well the heads are on the car - so not much of a chance to drill and tap -  i do have the larger tap but i'm not sure i can fit a drill in straight - :( plus cleaning out the shavings in the water jacket will not be fun

i do wonder about milling down the correct size - if its possible
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: BULLITT65 on April 27, 2015, 06:06:53 PM
I would strongly recommend not trying to drill or anything like that with the motor assembled in t he car. I have had to pull a head for a bone head mistake, it only takes about 20 minutes. Hard part is just lining the exhaust back up when I did it, (tight fit).
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: aaronz28 on April 27, 2015, 06:13:13 PM
yeah i'm not making that mistake lol

i'll either go with trying to trim down an OE sender or go with a smaller one and calibrate
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: L78 steve on April 27, 2015, 06:59:42 PM
Sounds like you will have more into machining the sender than if to pull, drill and tap the head. Every Dart head I ever ran had the correct size port for the sender.
Which heads do you have? And how much did you mill off the ends? Any problem with belt alignment?
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: aaronz28 on April 27, 2015, 07:04:45 PM
I didn't do the milling - Brzenski did the CNC work on a pair of Dart Iron Eagle 200cc heads.
they are atop a 421 small block - :D

(http://i593.photobucket.com/albums/tt20/aaronzl1/11195329_10152797283347374_1376533064_n_zps0me97q0i.jpg) (http://s593.photobucket.com/user/aaronzl1/media/11195329_10152797283347374_1376533064_n_zps0me97q0i.jpg.html)
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: L78 steve on April 28, 2015, 01:00:35 AM
Did you have to cut the drippers to get the rocker covers to fit?
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: aaronz28 on April 28, 2015, 01:02:27 AM
yep - and dbl the gaskets
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: BULLITT65 on April 28, 2015, 01:37:20 AM
Well it looks good. How much rear wheel horsepower have you estimated?
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: aaronz28 on April 28, 2015, 01:45:37 AM
thats a good question -
its a 9:1  421, hyd roller cam - 236-248 at .050 with 535/518 on a 106 - Dart Iron Eagles 180cc heads
Z28 intake, AED 850 holley -
wide ratio muncie and 3.36 gears - -

if i were running headers and a good exhaust - probably a shit-ton
but i suspect the manifolds and stock deep-tone exhaust will kill a lot of the potential - especially the top-end -  but i built it to be a grunty big-block in a Z28 look-alike package.

i'll know in a few days :D
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: BULLITT65 on April 28, 2015, 01:49:04 AM
Please update if you get to a dyne, or if you make a pass at the track. thank you
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: aaronz28 on April 28, 2015, 02:04:39 AM
i will - proablby not anytime soon, but i might take it to a F.A.S.T event at some point.

i have drivin it for the past 10 years with every iteration of Z28 glory :D
its literally been my Guinea Pig - -  i've had 3.73s, 4.10s, and finally 4.56s in it -  the 30/30 cam, LT1 Cam, a couple aftermarket disasters, and lastly the 140 cam -
stock intake, cross ram setup,
Gardners Chambered Exhaust, and their DeepTone System, finally a true 2.5 mandrel bent system with borla mufflers and headers for the last season before pulling the 302/crossram mill out.

now, i'm shelf-ing all the original $$$ parts and will run with the 421 for a while :D

cheers
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: BULLITT65 on April 28, 2015, 03:38:36 AM
That sounds like a lot of fun . So what set up have you liked the best so far? Which set up was the least impressive?
Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: aaronz28 on April 28, 2015, 10:48:00 AM
most impressive - was Crossram, 4.56s, headers, and mandrel bent exhaust with Borlas - -  but that was to be expected - -

honestly most enjoyable was stock intake/carb, 140 cam, 4.56 gears, headers with Chambered exhaust.

Title: Re: modded temp gauge for smaller sending unit anyone?????
Post by: X33RS on April 28, 2015, 11:04:04 PM
Aaron,
   I've drilled and tapped several heads for the large temp sender with the LS retro swaps I've done for myself and others, while the engine is assembled.  It's really not bad at all, however I have the engines out and on the stand and do it before I drop them in.
  I've bought alot of complete and perfectly running LS engines so disassembly isn't in the cards.  Since they have metric threaded holes, I drill and tap them for the standard pipe to install factory senders so original gauges in the classic vehicles work.

   All I do is grease the drill bit, and pull it every few seconds to clean and regrease, and work slow.  Do the same with the tap, every couple revolutions I clean and regrease and work slow.  I've done it this way a dozen times and never an issue.  I have pictures of the last one I did if you wish to see, but it's pretty straight forward.  After it's up and running I flush the cooling system for any possible debri, just an extra precaution but I've never found anything.  They've all run thousands of miles without complaint.

  My thought process was, even if a shaving got in there, what's it going to do?  Chew a water pump bushing?  A water pump replacement on an LS engine is a heck of alot cheaper than $200 worth of MLS head gaskets and new head bolts (torque to yield can't be reused)   needed to remove a cylinder head.
  I understand a gen 1 is cheaper in that respect, but just laying out the situation I've been in countless times that forced this decision.  No complaints here.