Hello Everyone,
  I'm new to this forum (Great place you all have here) and a bit new to the Y Blocks. I have now formed a love/hate relationship with my recently built motor. It’s a .030 292, all new valve train w/ hard seats, John M cam and blue thunder intake, headers, electronic distributor, road demon jr. 625 carb, high flow water pump and aluminum radiator w/ electric fan. Transmission is an AOD. A/F ratio ranges from 12.8 to 13.2 during driving and 12.2-12.5 at idle. Timing at idle is 14 with total at 38. I have tried switching from a 180 to a 160 deg thermostat with no change.
  As long as I’m doing 30mph or more the temps are fine but when I stop the temps climb up to 205 rather quick. I have confirmed the gauge with both IR readings and a second gauge that had NIST calibration. I have the fan on manual override to eliminate the fan temp switch.
  When I built the engine I did not drill the small holes in the deck as many do. My question is: Would it do any good to add a cross over in the rear section of the heads by connecting the 2 pipe plug ports that are on the heads right behind the intake manifold? This is a popular mod on many other engines and some intakes add this feature.
  Any other ideas and suggestions would be greatly appreciated.
 
Thanks,
   Wayne

Wayne
Located in Lineboro, MD
55 Retro Bird
65 Cobra FFR
69 Dart

Does it stabilize at 205? 205 really is nothing to worry about.

The steam holes probably won't help.



The fact that it occurs at low speed indicates to me that airflow across the core is insufficient, assuming that the temperature continues to rise above 205.



Lawrenceville, GA

Do you have the head gaskets on correct?  Front to front?  If there is a doubt look for a squared corner sticking out in the top front of the gasket, the rear should have a radius to it.  It is easy to see sticking out between the head and block.  Like Charlie says if it stabilizes at 205 it shouldn't be a problem.

Welcome! by the way.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

The thermostat only controls miniimum operating temperature.There has been some improvement found in switching to the "Robertshaw" type stat-(Mr Gasket for bigblock Chrysler available in 180 or 160 range) and adding a couple of small openings in the nose of it.Should be topics on this if you use the "search"  box at top of page.Also some have found improvement by putting a restrictor in the bypass hose so more coolant goes through the rad rather than just putting hot coolant back into the motor through bypass hose.Do a search as mentioned for more info.Welcome to the site.

  

I agree to what others have suggested, but would add this.

How is your AOD being cooled in a 55 bird? It should run fluid thru the rad and an aux cooler.. 55's didn't come with coolers in the Rad as stock, as you may know.

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

We are all fishing for clues here, are we assuming the fan you mention is additional to standard fan, or only fan on engine?

YY

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Wayne

Welcome to the forum.

I do not think the problen can be solved by anything that you do to your Yblock engine. If it was not a Yblock and your car was overheating at low speed but was cool at 30 MPH what would you check?

Is there a shroud on your electric fan? Is the fan BIG enough? Is it rotating the right direction? Is all the airflow going through the radiator? Have you blocked the top of the radiator on either side.

The suggestion to have a large external cooler for the AOD is good advice.

If this is on a Tbird what happens if you pop the back of the hood, does it cool down?

Can you get a large electric fan on a stand and put it in front of your car and see what that does to your water temps?

It`s not the engine unless the timing is very retarded. Pete

You,re right on track with my view, am waiting on more info to help sort this out, i,ve seen electric fans with blade pulling air in wrong direction if only fan on engine . But engine running hot at low speed is usually coolant flow problem or restriction etc. certainly theres no need to fit additional pipes as suggested. I feel wayne may need to carefully retrace steps on timing, air flow, head gasket installation etc. P.S. i,ve come across more blocked radiators being the problem! despite, "but its been cleaned out!" trouble is it was years back and fresh engine can still pump loose flakes of scale etc into core. time will tell.

yyy

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Oops!  I guess I misunderstood the problem, I thought it was overheating if he went over 30 and was fine under that.  I think I should read twice before posting. Disregard the head gasket comment.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

Gents,
   Thanks for the advice thus far. The head gaskets are confirmed to be installed correctly. I am using the high flow thermostats (BB Mopar my other love) with a 1/8 hole in the upper portion. The idea on restricting the by-pass circuit is interesting, I ll do search as suggested. The trans is not cooled through the radiator. I have a very large stand alone cooler and I maintain 170-180 degrees as measured in the pan. I agree the 205 doesn t sound bad but it climbs from 160 to 205 in about 5 minutes. So far I have been able to get it moving again but in a severe traffic situation I would be getting a little hot under the collar so to speak. I will run a few tests to see how high it will go.
  On a side note this thing is a blast to drive. I added a GM quick ratio PS box, F&R sway bars, KWB shocks, power disk brakes and 17 tires.
The fan is pulling in the correct direction, no shroud and yes it does cool down with the hood open. I may have to change over to a larger fan. The radiator is a new aluminum unit and the block was tanked and cleaned inside the water passages very well prior to assembly. My question was really whether or not there was merit to adding a crossover to the rear heads. This works on small block Fords and a few other engines but this is my first Y-block. I certainly understand the difficulty in attempting to diagnose something like this from afar. Thanks for the ideas!
  Wayne
 
I also have gotten the following message when I post:
The board administrator has requested that you must provide some message content within your post. You cannot post only HTML, Images, EmotIcons or IFCode.
Any idea what I may be doing wrong and what I can do to fix it? I typically type in Word then do a quick cut & paste since I'm at work I am now posting from home and have tried a few things hoping to get lucky.
 
 I read the other post and I see I'm not the only person having problems getting things posted. I have been trying to post this for the last 3 hours. I will try the notepad trick and the bla bla bla one too.

      Thank You,
             Wayne


Wayne
Located in Lineboro, MD
55 Retro Bird
65 Cobra FFR
69 Dart