What's up everyone...Got a question for you Motorheads out there...I just replaced a valve, push rod and rocker on my late 60's Chevy 350 w/TH350, in my 64' C10 Custom. Bit of info on the motor for ya', the 350 was rebuilt 3 years ago and was hardly ever driven by the guy I bought it from, mostly stock internals (all new), steel crank and an RV cam. The internals of the motor blew my buddy and I away...it still looked like it was just rebuilt! Very clean... Anyhow...put it all back together with new gaskets (double checked all the holes and part number on the head gasket) and then upgraded from points to an MSD HEI with MSD Supercore wires, Added some ACDelco Rapidfire #10 Plugs gapped @ 45 to the mix, new 50/50 coolant, new 180 thermostat. The water pump is new, new upper and lower hoses, flex-lite fan and a new shroud were done about two months ago. Radiator is 3 years old. Tuned the carb and slapped a new ProFlow1000 filter on the 4bbl. She fired right up...adjusted the timing...intial 10 degrees...backed it off a day later...and now we're working on maximizing the timing this Sunday with a 'On the Road then back to the shop' timing day to get the most out of it... Well, after all that...the damn thing is running warmer than usual...the dash needle (not very helpful as far as the actual temp) ran around center or a little over center on warm/hot days...but now this damn thing likes to run a little over center at 4:30am on the way to work and a bit more on the way home when it's hotter during the day. It has not pegged or hit the 'H' since this issue came about, not even close. If H was 10 on a scale, I would say it has not gone farther than 6.5-7, idling and from light to light on a warm day. The cast iron thermostat housing was reading 187-190 degrees with a digital lazer thermometer after a 40 mile/65mph drive home from work the other day...Not bad I'd say. So I've been asking around buddies, local shops, you name it and they all said it sounds like the motor is getting a little more heat from the HEI/Hotter plugs once I mention the upgrade. I'm hearing it's pretty common...but since this is my Daily Driver...I want to be sure all the bases are covered. So what do you guys know about adding HEI and hotter plugs causing the increased warmth? The truck runs great! Starts every morning, idles fine, accels fine, even while the old school gauge is reading higher then before with points, and it doesn't take long for it to sit awhile and the temp goes down. The overflow can on the radiator never get's to the point of belching out over the place. I guess it makes sense that the increased combustion going on in the cylinders from the new ignition would add some more heat? Someone please Slap the 'Worried Stupid' look off my face...Let me have it!! Thanks in advance!! MONDO
You said you replaced the thermostat.... Do you think you may have replaced a 160 deg stat with the new 180 and thus the temp increase?
The thermo that was removed was a 180 as well...I thought about pulling the new 180 and going with a 160...but with winter around the corner and possible 20-30 degree nights (not often, but can happen) I was concerned the 160 would be too low? Would 160 be too low for the winter... The truck has an electric choke by the way...Edlebrock Performer.
Those $*$(_&0790 electric gauges only give a idea of what is happening. A bit of change in the electrical resistance will change the gauge reading ie cleaner or dirtier conections. Leave the 180 in it and try adding a couple of degrees of initial advance back to it. Can not see how putting different iginion and plugs would cause it in themselves to run hotter unless you had major miss fire issues with the old stuff. Also was your old coolant STILL 50/50 or had it got diluted over time? 50/50 will show a LITTLE warmer than say 25 anti freeze. You should not have gone to a hotter HEAT range plug if you did, that is for fouling issues if needed.
'On the Road then back to the shop' timing day to get the most out of it... time it to proper specs with a light. no specs? time it with a vacuum gauge. then get a mechanical aftermarket temp gauge with numbers on it
Hey John, you reside in my hometown...Phoenix, born in Winslow, raised in West Glendale & South Phoenix. How is the Old Valley of the Sun? Interesting you mentioned 'Cleaner/Dirty' connections...while the intake manifold was off...while cleaning the gasket surfaces and parts in general, I did get carb cleaner all over the temp sensor that screws into the intake manifold where the spade connector for the temp gauge connects? Possible issue? Hmmmmm...should I swap it out for a new one? Not very expensive and a quick swap. As for the advance...you're right...we're going to mess with that Sunday, get as much as we can before we start pinging. The old coolant was 50/50 as well, and was only a month and a half old, done when I installed the new water pump/fan/shroud. As for the plugs...the 350 calls for a #10 plug in the Delco Rapidfire line up...and the 45 gap is the minimal gapping for the HEI distributor. I pulled the plugs twice this week and they looked great...however, I wonder if there is a milder plug that I can run with a 45 gap? Thanks for the help! MONDO
If the engine runs fine and the only new thing is a slight temp change I would watch it and enjoy the new performance of your changes. A little temperature is not a bad thing.
Hi Payaso: Phoenix is much the same hot and getting BIGGER!!. I've been here since '50 and seen alot of changes. Hell I've lived in the 59Ave and Thomas area for 25 years now and grew up at 18th St and Osborn.
do a plug check first thing, adding hotter ignition and such may have induced a mild lean condition. also are the head gaskets the same thickness as the ones that came off of it?
Checked the plugs...they all look good, when we dial in the timing tomorrow, I'll tune the carb again...Thanks. as far as the gaskets...yes, we used the 'stock' thickness FelPro gaskets...the head was not shaved either.
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