Hey Guys
Been building/budgeting the 396 over the winter. Cranked it today. It seemed to want to get hot after about 12 minutes. 200 degrees and wasn't nearly enough run in time....took the thermostat out and gutted it and put the base back in. Refired and ran another 10 minutes or so and temps begin to climb again. Shut it down. Questioning if I've done something stupid....I really don't think the head or intake gaskets can go but one way???/??? If so I guess I could have a restriction or air lock??

Haven't got the timing light on it to check timing..don't really want to run it again till I got this solved.

Frecking new tach wouldn't work....green wire to negative side of coil...red to 12 volts...black to ground and nothin...so I had to guess the RPMs...sucky way of doing this.

396 .060 375 horse power pistons
820 heads with big valves
270 Comp Magnum
Torker II intake
800 CFM carb
Headers-2" exhaust
MSD Dist w/6A Box

2 fans blowing like hell throught he radiator

HELP!!

jim

Cool it down and get a timing light on it.

200 degrees won't hurt it. Get it running and time it first, then play around with your carb.

low timing cause it to heat up? The bottom hose feels cool compared to the top...I'd think after sitting for half an hour both would be the same...I'm stumped.

Thanks Mike...I'll do that...I guess about 12 degrees before?

jim

After rechecking everything and Continues overheating, possible wrong head gasket?????????

noticed it wanted to smoke when it got hot..I realize rings have to seat but that also seemed odd....I was wondering if the coolant wasn't flowing in the block/heads....

How much smoke is considered FUBARBD?

low timing cause it to heat up? The bottom hose feels cool compared to the top...I'd think after sitting for half an hour both would be the same...I'm stumped.

Thanks Mike...I'll do that...I guess about 12 degrees before?

jim

Yeah ,12°-16°'s is a good start and your not running the RPM's up (yet) so total timing has little/no effect on it at the moment.
You might pull both radiator hoses off and run garden hose through in both directions to see the flow -with the engine off's fine.

Jim,
YOu did not mention what type of fan / radiator / shroud setup you have. Most cars will end up overheating if run for very long without a good cooling systme. You might want to get a big fan and put in front of the car, like they have at the emissions test stations, or have someone with a garden sprayer to spray the radiator a little to help it cool. Having the timing retarded will make the exhaust system run hot, and possibly burn an exhaust valve, but it really should not affect water temperature. I think almost any big block head gasket made will work ok on a 396, so I dont think that is your problem. Also ... make sure the gauge is correct. DO you have an infrared temperature "gun" or can you borrow one ?

You mentioned that the lower hose is cooler than the top .... that is how it should be. Hot water rises to the top, cool water falls to the bottom.

Also, like the others said, 200 really is not too hot, as long as it does not go any higher. My Tahoe runs at around 210 all the time, has since it was new.

Thanks Bill

I have a conventional big block radiator with a 18" fan and 5 inch deep chrome shroud. I used two fans blowing at different angles across the rad. I'm really not sure about the accuracy of the gauge...it's a cheapo at best. You know it doesn't help when it's 90 degrees outside.
I'm with you on the head gskts...most kits I've seen are for 396 thru 454.
I did raise the timing some and it seemed to help when I ran it again for about 15 Minutes at 2200 RPM. When it cools down to a chilly 85 or so outside I'll fire it off run it for a while and attempt to fine tune this Edelbrock carb. I am almost tempted to ship it back to the supplier and get a Holley...it idles better with the mixture screws almost seated. I guess it could be those metering rod springs too heavy for my cam/lack of vacuum. The float levels were no where close to correct....why would they send that out from the factory like that???
ANY EDELBROCK CARB SPECIALIST OUT THERE?
I talk too much when I'm hot, tired, and frustrated.

Thanks everybody...I'll stop whining.
jim

Is the radiator new? If not then possibly plugged or restricted. Take the top and bottom radiator hoses off and run a garden hose into the top and see how much and quickly it runs out the bottom.

200 is not bad at all when sitting still with new motor running 2k rpm to breakin a new cam/lifters,its when it hits 215-220 thats you need to worry and shut it down .

And when it gets that hot just have someone spray a cool mist of water with a garden hose inbetween the fans you have blowing and the radiator and that will usually drop the temps some. Also have the heater on full temp and fan on high to also pull some heat from the engine/cooling system too.

Lastly ,when you get a timing light you need to run at least 18 deg base timing with that cam along with 18 deg mech in the dist in by 2800 rpms.

Then 18 base + 18 deg mech in dist = 36 deg in by 2800 rpms.

For street you also need to run a vac adv too.

Scott

If you can't get to cool down spraying cool water on the radiator your having a flow problem for sure. With the stat gutted you should be able to see water flowing through the radiator if not could be an air bubble, bad water pump or a plugged radiator.

make sure the parts store didnt give you a waterpump for a serpentine setup. Theyre made to turn in reverse. jim

make sure the parts store didnt give you a waterpump for a serpentine setup. Theyre made to turn in reverse. jim

I worked at Carquest as a kid and this happened time to time. The supplier would put the wrong one in the right box, one customers 454 overheated like crazy. Didn't get it figured out for 2 weeks.

http://www.hbassociates.us/gaskets.html

It IS possible for a head gasket to cause overheating on a big-block Chevy. The situation would be when a gasket intended for parallel-flow cooling (and therefore having restricted coolant passages at the rear of the gasket) like the gasket on top in the link is used on a block that doesn't have the matching parallel-flow coolant passages in the deck surface.

In that case, ALL the coolant is forced to transfer from block to head through the very restrictive gasket; and there isn't enough coolant flow to carry away the heat.

Is that your problem? Probably NOT.

I'd be suspecting that you need nothing more than the garden hose that BillK recommends--although verifying your advance curve including the vacuum advance is sound advice.

I have N-E-V-E-R seen an "air bubble" cause a heating problem on any car where the radiator cap is the highest point of the cooling system. It can happen in some modern cars where the top of the radiator isn't the high point of the system. In any vehicle that has the radiator cap as the high point of the system, an "air bubble" is forced by both gravity and coolant flow into the radiator--where it isn't considered a "bubble"; it's just a low coolant level--so you add more coolant and it's gone.

I had two electrics on mine and it also rans in the 200+ range, put 7 blade plastic flex and don't barely get it over 190 now. And the timing thing sounds justifiable also !!

Schurkey,
Would that style of gskt be used in a Fel Pro set? Mine was the "2805" set that supposedly is for 396 thru 454. I am almost convinced that the darn thermostat stuck during the first run in scession....after I gutted it the water flows really fast thru the rad.
It's hot in NC and is always as hot in my garage as it is outside so that also doesn't help.
With .060 over bore and heads that were milled by previous owner (unknown amount) I may always be in for a heat situation. At some point I may have to invest in a larger radiator for this car.
I am always aprreciative of thoughts, critisms, ideas, and suggestions.
Thanks,
jim

Jim,

I would try another thermostat or make a round plate with a 1/2 hole in it. Sometimes if the water flows too fast it can also cause cooling problems.

If you get into a bind, I'm only a 1.5 hrs away from you and would be happy to come down and help sort it out.

Great 66 Bill.

I'll try it again today with just the thermostat base...seemed to help last night.

I may take you up on that Bill if this gets confusing again.

Thanks for the offer..stay tuned.

jim

Great 66 Bill.

I'll try it again today with just the thermostat base...seemed to help last night.

I may take you up on that Bill if this gets confusing again.

Thanks for the offer..stay tuned.

jim

Thanks!

Just let me know!!! :thumbsup:

FYI,you guys are off base IMHO ,the 200deg f his bbc is running at is "not overheating at all" esp for sitting still on 1st fireup at like 2krpms for 12-15 mins to break in a cam in bbc esp if he isnt running enough base timing lke i already suggested.

Giving advice for possible bad or wrong head gaskets and possible wrong reverse flow water pumps for a motor thats not overheating at 200 deg sitting still for cam breakin is likely going to send this guy chasing his tail in the wrong direction.

Now if its at 220-225 deg after 12-15 mins and rising then thats the time to worry and look for the simple things 1st like is the fan adequate /pulling enough air through the radiator or if running a clutch fan is fthe an clutch ok or maybe he needs a hd fan clutch that locks up better for more fan rpm at idle/low speed when motor gets hot,proper fan shroud, along with good coolent flow too and or good t/stat and proper radiator for application too.

But sending him looking for possible worng or bad head gaskets and reverse flow pumps should be left for after all the sensible items have 1st been checked/verified operating properly esp since 200 deg isnt overheating at all in a cam breakin situation with motor at fairly hi rpm 12-15 with car sitting still and low airflow through the rad.

And he should run a std 180 deg stat if he has std flow w/pump and a hi flow 180 stat if he is running a hi flow pump ,there is no need to be playing around with gutted stats or removing it when the motor isnt overheating in the 1st place for the situation its in sitting still breakin in a new cam at 2krpm & 200 deg.

Just my 2 cents.

Scott

200 Is Not Bad At All When Sitting Still With New Motor Running 2k Rpm To Breakin A New Cam/lifters,its When It Hits 215-220 Thats You Need To Worry And Shut It Down .

And When It Gets That Hot Just Have Someone Spray A Cool Mist Of Water With A Garden Hose Inbetween The Fans You Have Blowing And The Radiator And That Will Usually Drop The Temps Some. Also Have The Heater On Full Temp And Fan On High To Also Pull Some Heat From The Engine/cooling System Too.

Lastly ,when You Get A Timing Light You Need To Run At Least 18 Deg Base Timing With That Cam Along With 18 Deg Mech In The Dist In By 2800 Rpms.

Then 18 Base + 18 Deg Mech In Dist = 36 Deg In By 2800 Rpms.

For Street You Also Need To Run A Vac Adv Too.

Scott

X2

Also, typically a thermostat runs slightly higher than the rating. When I ran a 195 it usually ran 210, when running a 180 is usually ran around 200. Now I run 160 thermostats and it runs between 175-180 warmed up.

Also, if the temp probe is in the head, instead of the intake, the temp may read higher.

200*F is not hot as Scott advised.

Levon,thats to the point about the temp sender in the head,i meant to mention it but overlooked it,that typically reads 6-10 deg hotter too du to being near exhaust port/ex manifold.

Scott

Thanks Scott,

I just came inside from running it again at 2200 for about 18 minutes and it hung aroud the 190 degree mark. It's about 86 degress here with 90 percent humidiy so maybe it will be good to go.
I'm still confused about the adjustment or lack of on this brand new 800 EPS Eddy carb.
Went ahead and adjusted the floats as per everyone's suggestion that they are incorrect from the factory....they were.

It doesn't seem to matter if the mixture screws are run allmost all the way in.....another something to rack my brains...as if the 70s didn't.

jim
ps sender probe is in the head...

The screws in the carb will not do much at 2000 RPM. Wait until you can set the idle down then adjust them.

The Edelbrock will run like crap if the fuel pressure is above 4-4.5 psi. If you do not have a pressure regulator and gauge, I recommend you get one.

Glad to hear you got the temps squared away and that it was nothong major wrong.

To add to above suggestions,if the idle mix adj screws still arent active or making much difference when adj at ilde speed then dont forget to ensure the base timing is at 18 deg where it belongs.

Thats because retarded base timing can cause you to crank in more then normal idle adjustment to the idle screw to obtaind an idle. Having to do that pushes the prim thottle plates past the idle circut rendering the idle mix screws in-active or only partially active if the prim blades are only partially in/out of idle circut.

Scott

Big fan or two house fans blowing through the radiator helps too on break-in......
Also blows those fumes from the garage

Thanks to all.

It's been 22 years since my last engine build....got gun shy I guess. The engine cranks and runs fine. Does a 270 Magnum lope (396 .060) or just rumble a little? Doesn't matter either way...just want it to sound correct for what it is.

jim

The 270 magnum will have a slight lope in a 396

in my 396 engines i like to run a 160 thermostate with two 1/8" holes drilled in it about 180 degrees apart. this allows alittle water flow all the time to work out air pockets.

make sure you have the proper routing of the bypass hose on the water pump to the intake.

its also a good idea to run a heavy bottom hose , the cheap replacement hoses will allow the spring to be sucked up into the water pump and the bottom hose will suck shut not allowing proper cooling.

please make sure you have your timing dialed in before you start messing with the carb. timing timing timing is so important. proper timing will keep the engine running cooler and run a vacuum advance on the dist. plugged into full vacuum.

i run anywhere from 18-22* of initial timing with my total around 36-38* somewhere around 2500 rpms. i also run a canister on my hei units that are good for 10 more degrees advance.

so while i sit at idle i will have anywhere from 28-32* and when im cruising down the road i will have about 46-48 total.

of course when i punch the gas pedel that extra 10 degrees falls away.

i run stock style 3 row radiators in my camaros using a sbc fan shroud for that year and i run the stock style clutch fan. of course when your running a bbc in my applications i have to cut the fan blades down about 1/2" or so, that way they fit in the radiator shroud since the bbc sit alittle higher then a sbc.

my cars run right around 185 degrees it the hotest of temps when driving around town.

after you get the timing taken care of dial in your new carb, i'm not a fan of eddy carbs so i dont have alot advice to give on that other then trade it for a holley. im sure some of the same tuning could be used on an eddy like the holleys( like make sure you have your idle transfer slots "squared" and open the secondarys to adjust your idle speed)


i hope some of this helps, i wish i had this kinda advice back in the early 90's when i starting playing with my first 396.

havent read the whole thread but make sure if you run them the heater hoses arent hooked up in reverse.

200 for a new big block seems fine to me.
Heck when the last SB was new it would turnthat a lot...once Id put some break in miles onit and it loosened up the temps dropped considerably.
Even 210 isnt "hot".

Thanks again.
I'll install a 160 thermostat with the bleed holes....good idea. I have a by-pass hose from pump to intake and quality rad hoses. I'm not sure if the heater hoses are routed correctly...they were both 3/4 hoses which I was use to 5/8 and 3/4. My distributor is a MSD without vacuum advance....don't like it much...would rather have a GM HEI that's been souped up a little. Timing is around 20 degress and it cranks good....hi torque starter. This carb thing has got me stumped...the engine seems to have irradic idle.
No vacuum leak...small cam...4 speed car so no trans drag. I'll keep tinkering.
jim

JIM,WHEN YOU GET A VAC ADV DIST THAT WILL REALLY HELP THE IDLE IF YOU INSTALL THE PROPER VAC ADV CAN THAT CORRECT FOR THE CAMS/MOTORS IDLE VACCUM.

Let me now if you get a gm hei setup because i can give you a napa pt3 for a vac adv can that should work ok for your setup if you gibe me your motor and cam specs so i can have an idea of where the idle vac may be if you dont already know what it it with auto trans in gear.

BTW,160 is really no needed,180 is the sweet spot temp for most street perf setups and that what you should use becasue 160 deg (esp in cooler weather) will make the motor & esp oil take longer to get to op temp which will cause premature wear of engine parts etc,not a good thing. It been prover mults times over the yrs the engines like ours run most efficient at approx 180-190 deg f ,NOT 160. and even with a 160 stat more often then not the temp usually ends up stabilizing above 180 deg anyway even starting from 160 deg casuing increased engine wear untill the motor/oil get to a higher temp.

Just my 2 cents on that.

Scott

I'm no Eddy carb expert, but I have found some QC issues with a couple of them. You may want to check that all 4 venturi clusters are solid to the body of the carb, I had one where a cluster mount screw hole wasn't deep enough. Another the primary throttle blade was not fully closing.

JIM,WHEN YOU GET A VAC ADV DIST THAT WILL REALLY HELP THE IDLE IF YOU INSTALL THE PROPER VAC ADV CAN THAT CORRECT FOR THE CAMS/MOTORS IDLE VACCUM.

Let me now if you get a gm hei setup because i can give you a napa pt3 for a vac adv can that should work ok for your setup if you gibe me your motor and cam specs so i can have an idea of where the idle vac may be if you dont already know what it it with auto trans in gear.

BTW,160 is really no needed,180 is the sweet spot temp for most street perf setups and that what you should use becasue 160 deg (esp in cooler weather) will make the motor & esp oil take longer to get to op temp which will cause premature wear of engine parts etc,not a good thing. It been prover mults times over the yrs the engines like ours run most efficient at approx 180-190 deg f ,NOT 160. and even with a 160 stat more often then not the temp usually ends up stabilizing above 180 deg anyway even starting from 160 deg casuing increased engine wear untill the motor/oil get to a higher temp.

Just my 2 cents on that.

Scott
Can you add a vacuum advance to a MSD distributor? The cap looks like a tradition points type GM cap. That would help my budget etc.

I really think a vacuum advance (more timing) would resolve the idle problem.

Jim,some MSD dist can accept vac adv but you need to get model # off the dist and get with mds through their site or summit etc to see if your dist will accept vac adv.

But as you suspect i too feel a vac adv thats fully activated at idle giving approx 14-16 additional dg timing will help out a lot.

You neeb to get the idle vacuum reading with auto trans in gear to find out what vac adv can to get.

i have list for stock gm point and hei type dist so when it comes toime fore you to get a vac adv tell me which type and the ilde vacuum your motor has and i can hook you up with a napa pt# for correct vac adv. I believe some msd dist accept gm stly vac adv so ask that question too weahter its the points dist or hei dist type vac adv that fits the dist you have so i now which one to give pt# for.

scott

Jim,some MSD dist can accept vac adv but you need to get model # off the dist and get with mds through their site or summit etc to see if your dist will accept vac adv.

But as you suspect i too feel a vac adv thats fully activated at idle giving approx 14-16 additional dg timing will help out a lot.

You neeb to get the idle vacuum reading with auto trans in gear to find out what vac adv can to get.

i have list for stock gm point and hei type dist so when it comes toime fore you to get a vac adv tell me which type and the ilde vacuum your motor has and i can hook you up with a napa pt# for correct vac adv. I believe some msd dist accept gm stly vac adv so ask that question too weahter its the points dist or hei dist type vac adv that fits the dist you have so i now which one to give pt# for.

scott
Thanks Scott.

I'll do some homework and get back to you. I appreciate your help.

jim

Can you add a vacuum advance to a MSD distributor? The cap looks like a tradition points type GM cap. That would help my budget etc.

I really think a vacuum advance (more timing) would resolve the idle problem.


I had a similar issue, with my car having a distributor with no vac advance...

I bought a $90 Summit HEI ("new", complete with cap, rotor and 50Kv coil). Easy swap, and it ran low 13's with any tuning... Turned out the mechanical advance is setup out of the box for all-in by under 3000 RPMs (I think it was about 18 degrees, right where I was told I should be looking for), and while I haven't checked, its also supposed to have an "adjustible" vacuum advance cannister...

A bargain IMO...

http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM%2D850001R&N=700+4294908216+4294840140+4294881256+4294881252+ 4294881251+4294881254+115&autoview=sku



While I have heard of (from friends) a few (2) "bad" Edelbrock carbs (and oddly, BOTH were 750 cfm versions), still much fewer than the Holleys I have seen with problems... Generally, the Edelbrock will be a much easier carb for setting up or "first startup" on a new motor... I have installed more than 5 Edelbrocks on my cars and the cars of friends (along with several others who installed their own), and everyone had nearly flawless operation without ANY tuning or adjustment (aside from minor setting of the idle SPEED).

IMO, you should contact Edelbrock Tech, read the installation manual or find someone that knows about the Edelbrock carbs.

I compltely misunderstood this Thread. I took it as the engine was building up heat fast and was shut off before it got any hotter. I have a 454 and know for sure that 200 is nothing for a BB. As that is the hottest it has ever run but always at 180.
So yes JC396 was a little trigger happy...Glad your all set now...

I compltely misunderstood this Thread. I took it as the engine was building up heat fast and was shut off before it got any hotter. I have a 454 and know for sure that 200 is nothing for a BB. As that is the hottest it has ever run but always at 180.
So yes JC396 was a little trigger happy...Glad your all set now...
Thanks for your observation!
I take it to mean that this should be put to rest?
If it it weren't for issues/concerns, there would be no need for this site.

To All,
Thanks for everyone's advice and guidance, I appreciated all of it.

Respectfully,
jim