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

Welcome! by the way.

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

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

      Thank You,
             Wayne

Wayne

wayne, Tim suggested when posting to add another line below main reply, he uses bla bla bla, i use y y y and dont seem to have any problems since so far??  i start to think it may be browser problem but not real cluey on that part. regards bill.

YYY

From your description, this sounds like an air flow issue through the radiator at low speed. A coolant crossover at the back of the block likely will not help in this instance. A short cut fix (if this is an early ‘Bird’) is do away with the one inch spacer behind the water pump and then space your pulley back out the missing one inch. This has been proven to work in some instances for the parade cruiser crowd. And already mentioned is the installation of a restrictor in the bypass hose which is another quick fix for those engines that are just over the edge and need some help in bringing the termpertures back in line.

Here are some other threads on the ‘steam holes’. Those holes are obviously too small to be called ‘coolant holes’. The original intent of those holes is to simply remove the air pockets that can get caught under the decks in the block which turn into hot spots under the right conditions.

http://forums.y-blocksforever.com/Topic31939.aspx

http://forums.y-blocksforever.com/Topic10608.aspx

http://forums.y-blocksforever.com/Topic35997.aspx

And here’s a picture of said hole in a CITE head with the resultant crack going through it.

This photo shows the stuff I've most recently installed - (1) smaller diameter Ford 302 single groove pulley with adapter spacer for alignment (already had six blade fan and factory shroud) (2) 180° high flow thermostat with three bypass holes drilled in the nose (3) 3/8 npt brass pipe plug drilled with 3/16 hole insterted into bypass hose

The multiple holes in the thermostat substitutes for the usual flow through the bypass hose at start-up

The 3/16 hole in the bypass plug allows for an air bleed at shut-down

pulley size reduction gets the fan speed up at idle 

I check the temps with a gauge and the sending unit is in the water jacket in the block. I just used an IR on the freeze plugs to double check the gauge reading. I think I’ll try more fan(s) and/or a shroud. I have another fan I can mount as a pusher to help the existing one. That should tell me if I’m heading in the right direction. I may also try the smaller pulley. I have to check my parts bins but I think I have a 302 water pump pulley in there. Thanks for the ideas!

Side note: Saturday is my parent’s 50^th anniversary. My Dad got this car in 79 and we have spent the last year and a half working on it. They will ride to the church in it on Saturday to renew their vowels. This will me my Mothers first ride in the car.

Thank You,

Wayne

So far, Casco has the best solution with the added blades to the back of the impellor. Yeah it looks a little primitive but it does work.

Thanks All,

   Wayne

Wayne