newly built 416 getting warm

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ltrripp11

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just a cooling question here. recently had a 416 stroker motor built from a 340 duster. outside of the obviously larger cubic inch the rest of the package is relitevely mild. it has the original x heads coupled with an elelbrock rpm intake and comp cams 268h hydralic flat tappet and new summitt 750cfm carb. nothing to racey. on the cooling side its all o.e.m with the 22inch 340 radiator (new) with a new thermal fan clutch, stock shroud and 180 thermo all in working order. just started to drive the break in miles and its right at 180 or bellow while under way. when i come to stop and go traffic however it rises quite quickly. later at idle for about 15 minutes it steadily rose to 218 and stabalized. this on a 60' day. obviously radiator time i guess.

so my question is what radiator to get that will fit properly and not look to out of place and where. the engine bay was kept all stock looking and the car is showed. im leaning towards aluminum but need advise. also whats the difference between cross flow and downflow types besides the look? any advantages to either? need to be educated. thanks.
 
I don't believe you have an issue if the temp never gets over 220. Modern FWD cars get up to 210 before the electric fans even start going and they go to "fast" at 220 and regularly reach as high as 230 for a peak.

I run a 195 degree thermostat because the engine is more efficient at that temp, it cools fine. If you get over 220 after a long idling period, i'd start to get worried...but 218, then cools right off if you start driving again is not an issue IMHO.
 
I would think it's an airflow issue because it's fine when moving. So really, you can either get more air thru it, or get more surface area fo that air to flow past. The factory ones are 2 core. You could have your tanks and brackets put together with a 3 wide core. Also, as said, it should be running a little cooler after the rings finish seating. Also, make sure you changed your break-in oil after the cam breakin. What oil pump was installed?
 
so temp rises at idle and low rpm...right ? what is timing set at ? and are you running vaccum advance? low timing at idle will cause exessive heat, also is the motor running fat???? or lean lean causes heat also.....figure this out real soon critical on a new break in.......be careful of detination also causes heat.....
 
thanks for all the feedback. some good points on the break in and timing. the timing does need to be kicked back. im getting some detonation under load up hill and when getting hot so thats the first step. i waited to see if a full mixture of 93 octane would do the trick but its not. if the break in and timing dont solve it i will probably re-core the original to a 3 core and go with that. its a new o.e.m. radiator so i dont want to waste it. hopefully that will be enough. thanks again.
 
I'd get it recored to a 3 core...or get a Mancini alluminum unit. That's what I bought, yet to be installed. You can then get some black radiator paint and spray it. It will look as stock as possible and be a nice alluminum unit. Either way would probably work. I can attest the custom built Mancini units are very nice (but pricey).
 
from experince,get 8 blade water pump,clutch fan should go, alum rad knocks about 10 to15 degrees off. also i bought a alum balancer pulley looks great but car ran hot and had to put factory pulley back on. also the water wetter jegs or summit sell helps to
 
Does the fan go about halfway into the shroud? If it is too far in or too far out, the shroud is ineffective and the fan won't move as much air.
Warming up at idle or slow speeds is indicative of not enough air flow through the radiator.
What kind of temperature gauge do you have?
 
If you put your hand around the front of valve covers when its idling you should feel a nice steam of air coming from the fan. If you put you hand in front of the radiator when idling you should feel air getting pulled through. I would be very suspicious of that fan clutch and make sure fan is bolted on correctly.
 
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