70' 455, complete rebuild, .30 over clean up and slight decking job to true up surfaces, motor is running (per the new set of gauges) at 230 degrees. Idiot light on dash is functional and not showing hot. New water pump, new thermostat (160), new fan clutch, original radiator cleaned and new end tanks installed, shows to be flowing well with cap off. Not trying to belch back water after motor is shut down so don't think I have a head gasket issue. Motor not creaking or popping after shutdown. New autometer temp gauge, but needle does not sit completely on "0" when cool. Can I have a new gauge that is bad ? Going to try and borrow temp gun and shoot the block while running tonight. Thanks

 

Once upon a time as a teenager I had a similar situation, I did not check the length of the temp probe for my gauge setup and the bottom of the probe made just enough contact with the bottom of the intake manifold that my new engine appeared to run way too hot during the break in process. While this might not be the cause for yours, might be something to verify. Needless to say, I have checked that little nugget every time since when putting a gauge setup in a new or existing engine. Fool me once...

 

Cruising or idling? Mech or electrical guage? How much break-in on engine?

 

Is your timing set right?

 

X2 on the timing

 

Yep checked it twice with the light and it's a mechanical guage

 

At idle after running down the road to bring it up to operating temp.
About 45 mins to 1 hr on break in. Holds about 200 -210 at road speed

 

A fresh rebuild will have a tendency to run a bit hotter. What is your timing set to an what distributor are you running? Was a BB original to the car?

 

What is your piston to bore clearance? What is your piston to pin clearance? It's not uncommon for people to make these too tight and generate extra heat.

 

The person that built motor set up all tolerances to w-30 factory specs and installed a nostalgia grind comp cam. Meticulously went over and checked tolerances and ring gaps. He has built dozens of these motors and I'm sure that is not an issue.

 

Any engine i have ever built has run hot initially, until it gets broken in good. Tolerances are a little tight at first. Unless its just way too hot i wouldnt worry too much, run it, break it in, drive it, get some miles on it and i bet it will start running cooler. This has always been my experience with new rebuilt motors. Just be sure the timing is set right, fan and shroud are good, radaitor is good etc.

 

Is this a 4 row radiator? Copper/brass?

 

Do you have a shroud and have you checked it with the IR thermometer yet?

 

Original born with shroud in excellent shape. Clearances all correct front and sides. IR gun shows temps varying from 210-230 depending where you shoot. I took readings on the pump housing, heads , hose and intake. Of course aluminum intake reads much hotter(250). I drained the radiator and fill with mostly water, added water wetter and even gutted the old thermostat and put it back in. Still creeps up to 230 after 15 mins of idle or after a couple of miles on the road. Still does not belch back coolant. I'm going to change gauges today just to make sure that isn't the issue. Then I'm going to run it a few miles to see if it gets much past 230. If so I'm going to check for a head gasket issue

 

Original 4 row BB radiator, flushed and new tanks installed on both ends. flows well with cap off. I'm using a generic radiator cap (16 lb) at the moment could that have any effect?

 

Nothing wrong with the radiator cap. Does it have the original carb on it? If it's running lean it could make it run hot.

 

Original Q jet rebuild kit installed and set properly

 

everything sounds right ...new parts, proper settings (only other thing i can think)unless freeze plugs were knocked out and not removed and coolant circulation is restricted (not likely).... like others said it a new rebuild and will run hotter or it could be your new the gauge is off, run it another couple hundred miles local knock on the gauge with your knuckles and see what happens

also 200-230 is hot but not in the red overheating so even more thought that its tight

 

Sound like not enough piston to wall clearance. What pistons did you use?

 

Here's a thought also. Less than 2 hrs on the motor run time. Still has break in oil in it. I think I'm going to go ahead and change out the oil & filter. Is there an additive I should put in in the new oil since it may just be tight still?

 

2 hours isnt much but you will get a bunch of opinions on new engine break in i like using 10-40 for my stuff and neck of the woods and the lucas additive is easy to get (i use some additive i have bought online but cant remember the names) but you should use something if you change the oil to be better safe than sorry

 

i'm trying to be optomistic and these things always come up after new builds...hight temps weird noise, leaks, funny smells etc. i think its best to just wait it out drive it carefully then reevaluate after a a few hundred miles unless something is clearly wrong

 

Thank you very much for all the input guys ! The worst case scenario of having to pull the heads or something drastic like that doesn't scare me. If it happens, it happens, go forward. But damn that motor sounds so good that I really don't want to mess with it. I'll just drive it some more and see how it goes. Thanks again

 

What distributor are you running?

 

Stock w HEI internals

 

Is the radiator core still the original?. I know you have flushed it, but if it has a layer of scale built up in it that won't flush out. Maybe it can be removed with chemicals, but it is a quite effective insulator.
Also your engine is not only possibly a bit tight from its rebuild, but now has mods to make more power. If it makes more power it will make more heat, it could be the radiator would be fine with original spec but struggles to cope with the new setup.


Roger.

 

little nascar trick drill a tiny hole in the thermostat buy doing that all air in block will burb itself

 

All the additives and tricks in the world, or hours of run time, won't cure a hot running engine. If it cooled fine during normal dtiving before it was rebuilt it should cool fine after being rebuilt. Its that simple. Makes no difference who built it or how many they have built. Unless there is a serious issue in the cooling system, which there does not seem to be, or a big error in the ignition timing, it all points to not enough cylinder to wall clearance.

 

Smitty thanks for that input and I'm feeling you may be hitting the nail on the head unfortunately. That being said is there a chance the rings have not seated yet with less than two hrs on the motor? And if so should I just take her out cross my fingers and put it on 75 or so and drive for 8-10 miles until they seat and then the temp should ease off (theoretically...)

 

Good advice, especially from Smitty. Find out what pistons were used and what piston to wall clearance was used. Also, you can try richening the primary side jets .001" or so, and remember that stock timing on most engines of that era were somewhat retarded for emissions. You want to disconnect the vacuum advance, set initial at 12 degrees BTDC, total mechanical advance 36 deg. Mr. Gasket offers a brass bushing in their advance kit in case the stock rubber bushing is worn or gone and you get too much advance. then hook up the vacuum pot to either the ported position on the carb, or the manifold directly (if that doesn't cause pinging). Also, what gas are you running? If it was built to stock W30 specs, compression could be high for today's gas, unless the cam bleeds off some compression by having a lot of valve timing.

 

Oh, another point, today's engine oils are not friendly to flat tappet cams. Either run specialty oil with lots of ZDDP, or Comp Cams additive. Some cam break-in lubes, with moly, plug the oil filter during the 30 minute cam break-in at 2500 rpm (you did do that, right?--if not, the cam lobes might be wiped).

 

Theres a thought...ask the shop what clearance was used and you will get a good idea from his response if he defensive or says 1-2 thous ir confident 3-4 thou ...etc maybe he will know for sure

 

If the rings didn't seat almost immediately upon firing the engine then they never will. The #1 reason for a rebuild to run hot is because the piston to wall clearances are too tight. I've seen it over and over. Guy has engine built buy whom ever engine builder and they put them in at spec. Engine runs weak and/or hot. Bring it to me to fix. Hone cylinders for a more appropriate piston to wall clearance and put it back together with new rings and the engine runs strong and cool as can be.
If you not willing to live with it you may as well yank it and check it out and rectify the problem.

 

well thats a tough decision... i certainly wouldnt be pulling the engine at this point with around 2 hrs, not even sure what type rings, cylinder finish, pistons break in oil used or possible defective gauge... ... i hope the best

 

Nix the gauge issue. Slapped on another last night. Same results. headed to build shop to talk with mechanic and get specs/info, pistons rings ect

 

Break in oil has zinc additive. Slathered cam with break in lube when installed. As well as valves, rockers, cylinder walls, pistons, rings, bearings, crank Did not block off filter for initial break in.


Pistons- speed pro forged- .030 over
Rings- Hasting- gapped to specs

 

Cam lube on the cylinder walls will prevent or make it difficult to break in the rings. Use engine oil only, and not a lot of it, on the rings, ring lands, cylinder walls.

 

My bad was not clear there,
cam lube on cam only. Beak in oil with additive on the rest. Poured it in hand and rubbed even coat on all parts

 

I don't feel the cam has been damaged. no lifter noise or chatter. As I said earlier the motor sounds great. That's why this is so maddening. I may start drinking heavily about 5:00 p.m.

 

What kind of pistons were used- cast or forged?
Factory specs are for factory CAST pistons.
I too have a 403 that was built with forged pistons, and... 0.002" wall clearance. SCUFF SCUFF SCUFF the walls and pistons. I bought the thing, tore it all down and saw the problem, read up here and elsewhere, and asked the machine shop to hone to 4-5 thou clearance- about 0.001 per inch of bore. They resisted, said it will be noisy, not to spec, blah blah blah. I said just do it, I will live with the "noise." Engine runs proper temp and I have never heard any problem noise. And, this is a competent machine shop. For this area.

Smitty, is 0.001 per inch of bore what you use for forged piston to bore clearance?


"little nascar trick drill a tiny hole in the thermostat buy doing that all air in block will burb itself "
====================
that sounds like like SOB [Some Other Brand] voodoo. With the ~1/2" diameter bypass hole right there an inch away, what good is another hole thru the t'stat?