Good morning! I replaced the original 216ci straight-six in my 1950 Chevy Styleline with a crate 350/190hp engine. It's running an Edelbrock intake & carb, headers, 165 degree thermostat, and a cheapo ebay HEI ignition. My car runs at about 190 degrees (190*) all day cruising down the road, but when stopped, or in traffic on warmer days, I've seen the temp creep up to 230*. Just this past weekend I replaced the original radiator with a 3-core aluminum radiator with 16# cap, and it really didn't change the temps any. I currently have a 7-blade flex fan on the engine - don't have space between the water pump and radiator for an electric fan. On the old radiator, I tried a 12" electric in front as a pusher, but again that didn't seem to help much. After doing LOTS of reading, I'm wondering if ignition timing can be causing my high temps. Using my timing light, here's what I'm seeing. Vacuum advance disconnected: distributor set at 10* initial timing @ about 600 rpm All-in mechanical advance is about 32* at 2000rpm That tells me the mechanical is adding 22* advance Vacuum advance connected: 36* at 800rpm (normal idle speed) - vacuum advance adding 26*?? (13* at the distributor?) 58* at 2000rpm - again, mechanical advance adding 22*. Is that idle advance too high (36*)? Should I look for another vacuum advance canister with a lower value, or make a limiter plate? Or am I chasing my tail on this, and it's all an airflow issue? Or is 190-230* an acceptable range? I'm not getting any 'puking' into the catch can at all. Thanks!
as an easy, quick, experiment, try connecting the vacuum advance to the ported vacuum connection on the carb (one that does not have vacuum at idle, but does after you open the throttle a little ways). It might help, it might not. Also try bumping up the timing by 4 degrees. And you might also try a vacuum advance can with less advance, just for fun. If you provide pics of the front of the engine, radiator, fan, etc from a few different angles, we might could see what it looks like, and maybe notice something about the setup that you overlooked, that you could improve.
Also, where is the temp sender located? if it's on the head, not the intake manifold, then we would expect it to read kind of high when it's idling.
The heat range of the plugs makes a difference, a 'colder' plug will let the engine temp run cooler. The plugs will shed the heat quicker keeping the temps lower to begin with.
230 is not too hot, but the fact that it rises 40 degrees when idling isn't good. If it stabilizes at 230 it is not hurting anything but as the system ages, temps will climb higher. Advance the timing and going to ported vacuum may help. Changing the plugs heat range will not. That has nothing to do with engine temp. Adding a fan shroud will help if you don't have one.
your timing is way to high for a 190hp 350. im surprised your starter isnt kicking back. you dont hear any knocking? i would drop the initial timing to around 13deg and all in around 30deg. didnt you crate motor come with a timing baseline?
Manifold connected vacuum advance will add lots of timing at idle, this is useful for keeping temperatures down at idle and stop and go. It will not cause any problems because there is no load on the engine at idle. You'll see eye popping numbers - 50°+ BTDC in neutral when observing with a timing light but again, there's no load on the engine. Vacuum advance is strictly load based, you won't see quite those numbers cruising down the highway on level ground. Retarded timing will cause overheating as well.
@Omarsvette - my initial timing (vacuum advance disconnected) is 10-degrees. With the vacuum advance connected it's 36-degrees. Here are a couple of pics of my setup. The temperature gauges is an Autogage mechanical unit, connected at the front-left corner of the intake manifold. IMG_6377 by krbarnes posted Jul 4, 2017 at 11:57 AM IMG_6376 by krbarnes posted Jul 4, 2017 at 11:57 AM IMG_6375 by krbarnes posted Jul 4, 2017 at 11:57 AM And YES, I know I need a fan shroud. That's next on the list.
Throw that 165 thermostat away and put a 180 or 195 in it. Add a shroud and you should be good to go. Sent from my Moto G Play using The H.A.M.B. mobile app
I agree totally with this and was planning to make a similar post, just got 'beat to the draw" Also, you said you are running a flex fan Those things seldom work Try a good 6 or 7 blade steel fan along with a shroud.
I'm pretty sure this is not correct. If anything, a colder plug transfers heat quicker to the heads, leading to more heat in the coolant, but I really don't think this is going to show on the gauge at all. To the OP, getting hot at idle indicates to me that the issue is related to 2 things, reduced air flow through the radiator, and reduced coolant flow through the engine. For airflow, try replacing the flex fan with a solid fan and installing a shroud. If possible, a smaller water pump pulley will increase both fan speed and coolant flow rate.
Before anything else add a good shroud, a good solid high pitch fan blade wouldn't hurt either. I think after this your problem's will go away.
right so at idle, with vacuum connected, at a stop light your temp climbs to 230ish. thats a lot of timing at 36deg. your set up looks good i.e. radiator higher than motor. your lack of shroud shouldnt matter too much, or fan choice,thermostat..not enoughtclimbfrom 180 to 230. we are talking about a very mild 350 not a high compression race motor. your getting cooling because when you drive your temp goes to 180deg. do the easiest thing first and bring your car to operating temp and drop that timing down. if that doesnt fix it then im wrong and bring your timing back up and start messing with your cooling system. think about it, very mild cam, 8 to 1 comp and dish piston with restricted heads, doesnt need a lot of help cooling.
It would be an easy quick test to swap the distributor over to "ported" vacuum. If it's overheating now though it may get worse, not better. The 70s smog era distributors ran on "ported" vacuum for emissions purposes but it would default to full manifold vacuum in the event of engine overheating, to help lower engine temperatures. 36° sounds like a lot but at no load idle it won't ping or anything like that.
krbarnes, Remember the cooling rule of thumb. Runs hot at highway speed = not enough radiator. Runs hot at low speed = not enough fan. I believe you replaced the radiator for nothing. You've got a fan problem. I'd also replace that flex fan with a steel engine driven fan. Gary
With the fan some distance away from the radiator and no shroud, very little air will be pulled through the radiator. Just like me, nature is lazy - if it's easier to draw air in from the side between the fan and radiator rather than through the radiator air will mostly be drawn in from the side - and just circulating hot air inside the engine bay does nothing to cool the engine. All those countless car owners who have changed their original radiator to a high performance unit and left the original shroud out because it doesn't fit the new radiator, only to get MORE overheating problems... No matter how good the radiator is, if too little air moves through it, it cant work. Step one: Get a shroud. Air needs to go through the radiator to cool it.
You need a shroud and electric fan. I,m a product of the late 50s and 60s to present and do not change very easy but do like electric fans on the street.
Never had any luck with those flex fans, ditch it and put a stock 5 blade on it and solve the cooling problem.
I can't find an electric fan thin enough to fit between the water pump and the radiator. Right now I have less than 3 inches. When you guys are saying to get rid of the flex fan and get a steel fan, are you talking about something like this? https://www.summitracing.com/parts/der-17317 Fan by krbarnes posted Jul 4, 2017 at 8:15 PM
Yes, that's the fan you need, or one like it, and I still agree with Truck 64 about your spark advance.
Give this man 10 silver dollars for the correct answer. That flex fan positioned so far from the radiator core without a shroud is doing next to nothing to draw air through the core at slow speeds or while stopped. You also need to make sure that all of the sheet metal is in place that your car was designed with to make certain that the incoming air is being routed through the radiator and not around the sides or over the top.
the vacuum advance is in the wrong place,try the ported vacuum as mentioned earlier. also drain out that 50-50 mix of the green slime any freeze it makes the engine run to hot not needed in the summer replace it when the winter comes if you're in freezing weather that should fix your problem guaranteed Sent from my iPhone using H.A.M.B.
Two points: The pressure of the rad cap has nothing to do with controlling temperature - it only controls how hot the boiling point is. Retarded ignition will cause overheating - too much advance won't.
How does antifreeze make an engine run hotter? I would never run an engine without it, as it's also a corrosion inhibitor.
kr, I had the exact issue with my Deuce roadster, It was only because I was just too lazy and just wanted to get my car on the road. I drove it for a couple of years like that. Fan too far from the radiator and no shroud. I installed an electric fan with a shroud and can sit in traffic, ( I live in NY, worst traffic in America) for hours and it does not over heat.
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