overheating(too hot for me anyway) 360

[cudanut jim]

I just put a 1975 360 c.i. in my cuda. I also put the 915 "J" heads on it that I had on the 318 that was in the car. I checked to make sure there were the same cooling port hole on both heads, which they were. I just checked to make sure the head gaskets matched up with the heads. they did except for a few small holes. The listing said they're for a 360. The car runs normally at about 190 deg. After driving on the highway on a warm day and i get off and into normal traffic the temp gets up around 230 deg., which in turn, when I stop at a red light the car wants to stall out unless I shift the 727 trans in neutral. I put a fan spacer to have the mechanical fan about 1" from the radiator. I do NOT have a shroud and will be picking one up at the mopar nats in August. I'm wondering if either I put in a junk thermostat. Any ideas?

[440roadrunner]

I would try and find a QUALITY stat......used to be stant

If you google around, there might be something to problems with water pumps. I'm speaking here of too much clearance between the rotor and timing cover, and cheap crap rebuilds of late, (cheap and crap applying in general to many car parts lately)

I would DEFINATELY get a shroud. What do you have for a fan? Flex? These are not necessarily "better"

It seems to run cool at speed? Say, 35 and better? Sounds like a low speed airflow problem, or a water pump problem

Make CERTAIN your temp is what you think. Trusting a gauge is NOT. Get an infra-red heat gun, or even tape a stem thermometer to the bottom of the top hose with a rag taped around it

You might also have fuel vapor lock / boiling issues

[dakman1]

Also check your radiator cap. A week cap will cause overheating issue's too.

[cudanut jim]

I actually made a temporary shroud last night and I'll put it on today. I put the factory 4 blade fan back on. I had a 5 blade clutch-type on. Next will be the stat. I'll also pich up a cap which I didn't think of.

[whtbaron]

All of the above, and on a new install I'd say double check your timing to make sure the marks aren't doing something goofy to you.

[440roadrunner]

A good working 5 blade clutch would be far superior to a 4 blade. The 4 blades would be 318 2 bbls and slants. This is not to say the clutch might be bad.

[cudanut jim]

I changed the stat from a 180 Stant to a 180 Gates. Same effect. I did take the Stant and put in in a pot on the stove with a thermometer in it to check it out. It opened at 180 deg. Then I put a purge funnel on the radiator to get any air out. Lots of air bubbles. I took a drive on the freeway and then sat on the driveway running and still got to 240 degrees. I am checking temp. with a laser thermometer in different places. Tonight I'll do a super flush and a backflush to possibly clear any clog. I could put my 5 blade clutch fan back on too. 1 week to the Mopar Nats and not looking good!

[whtbaron]

Starting to sound like it could be a poor water pump, but double check that timing too. Doesn't take much to make things heat up.
What do the internal openings in the rad look like? You could be losing flow if it's starting to corrode with calcium.
Another thought... this couldn't be a lean fuel issue could it?

[chirorod]

I'm with whtbaron about the radiator. It's probably plugged up.

[440roadrunner]

Not the radiator if it runs OK at any speed. This is an airflow problem, or possibly a pump.

[cudanut jim]

The radiator is in good shape. It is a 2 core 22' aftermarket from a place called Complete Radiators. It worked pretty good in my 318. Last night I used a complete flush kit to maybe clean the system out. Then I did a backflush. No progress. It is a used 360 block from a guy who said he had it checked out. He showed me the receipt from the machine shop. I'm thinking I will pull the intake off and make sure the intake gaskets aren't blocking a cooling port. If that's not it I'm going to buy a NEW, not rebuilt, water pump since the cooling system will be drained. I don't like buying things for a "maybe it will work" but I'm running out of ideas. I'll double-check the timing first though.

[cudanut jim]

The timing is set at 3 deg. BTDC

[440roadrunner]

Originally Posted by cudanut jim

The timing is set at 3 deg. BTDC

That is nowhere near 'how' it should be for good drivability / performance.

You might need to recurve the distributor

Generally you want a fast curve, and the hotter the cam, the shorter the curve. For "mild but not factory" cams about 20-22 crank degrees in the distributor. This in other words is how far the mechanical advance MOVES.

For hotter cams, less. Some guys even use locked mechanical advance, but on the street that might not be so good.

You should be running AT LEAST 12 BTC and depending on the cam, maybe more, 15-20. That's right. 15 OR MORE BTC

TO DETERMINE optimum idle / initial timing. Unhook the vacuum advance. Warm up the engine and hook a tach up, and a vacuum gauge to full manifold vacuum. Adjust initial thiming for highest vacuum / RPM, and readjust idle speed AND MIXTURE for optimum

CHECK this by starting.....when hot......several times. Check for starter kickback. Drive it a bit.....HOT.......and check for ping at low speed "hard pull."

===============================

WOT full power. This is usually 32-38 total timing, the vacuum will not be active at WOT. Modern builds seem to "lean a bit less" 32--34 or maybe 36. This is best done on a dyno, or use something like a G-tech accelerometer. Tune for max HP yet watch for ping. Check the plugs for burn.



===============================

Now you must re-curve the distributor to meet the two points above. This is where the 20 degrees or less "at the crank" comes in. KNOW and UNDERSTAND that almost all books list DISTRIBUTOR degrees not crank degrees. You multiply the dist. listing X2 to get "crank" degrees. Look up some of the specs on things like the 66-67 hemi / 440 cars, or the 68 340 cars to get an idea of the factory stuff

ALL distributors built for "smog" cars after 68 got worse and worse.......long, slow advance curves. Utterly useless

In other words let's say you determined best idle (initial) was 17 degrees. Let's say you determine best WOT performance is 36 degrees. Subtract the two That leaves 19 degrees the distributor must advance the mechanical. "Forget" vacuum for the present

================================

Last your vacuum gets "added on" to the WOT 34 degrees or whatever you end up with. This can be as much as 55 degrees OR MORE and is only active under "light cruise" "light throttle."

Here is a hemi curve "factory."

See where it says

"Degrees at distributor (RPM)" This is the mechanical. Looke where it says 7.5--9.5 at 1400 RPM. This is 19 degrees (9.5 x 2) at the crank, all in by 2800 RPM (1400 RPM distributor RPM x 2)




Now, you can buy aftermarket performance distributors with adjustable advance. Accel, Mopar Performance, Mallory, MSD, maybe others. Or you can recurve or have yours recurved. Here's a very good article

http://www.moparmusclemagazine.com/t...nition_system/

Also, this "FBO" outfit makes a kit for Mopars which is an add-on limiter and spring kit. This adds into the mechanics of your factory mechanical advance

Here

http://www.4secondsflat.com/Ignition.html

Go down the page toward the bottom left and find

" J685K Limiter Kit

All Mopar Electronic Distributors"

[whtbaron]

3 degrees by the marks... but did the marks get changed?

A 21" 2 row rad isn't really big either. I'm wondering if that rad was marginal capacity for the 318 and just isn't keeping up to a mid size V8.

[cudanut jim]

Yesterday I put a new water pump on with 8 blades on the impeller, which I figured was a great improvement on the existing 6 blade rebuilt cheepie I had. I also bought a radiator cap. A test drive a couple miles seemed to finally fixed my problem until I saw a freshly painted '70 Challenger on a trailer at a store and pulled in to talk to the guy. I left my engine idling while we talked and went back to my car to see the temp gauge at 250 degrees. NOT fixed. There's gotta be a blockage of some sort in the used block I bought. Any ideas would help because I'm almost to the point of no possible clues to fix it.

[chirorod]

I seriously doubt the block has blockage, but could have a crack. Was it magnafluxed or dye-checked? Is there water in the oil?

[440roadrunner]

I'm tellin ya. This is most likely LOW SPEED AIR FLOW

[quietdad]

You get a shroud on it yet? My Roadrunner will NOT stay cold without one regardless what I do.

[cudanut jim]

Well, the radiator was in good shape until one of the sharp edged zip ties I used to hold my hillbilly home-made shroud pierced a water passage in the radiator. A lesson learned! I bought a 3 core aluminum radiator, and low and behold, when I put the new radiator on I found the problem. The lower radiator hose collapsed at the bend which restricted the flow and caused the engine to get too hot at low rpm. Now with the new radiator it doesn't get above 190 degrees even in slow traffic. Mopar Nats here I come! Thanks for all the input and help.

[whtbaron]

lol... well there's the one problem that none of us mentioned! Glad to hear it worked out for you.

[John Kunkel]

Lower molded hoses used to come with a coiled wire inside to prevent the hose from collapsing but no more. I always install one.

[cudanut jim]

A guy I know told me to twist a coat hanger around a piece of 1.5" pipe to make a spring for the hose. Kinda cheesy I think. By the way, my car made it to and from the Mopar Nats in Columbus Ohio (200 miles each way) plus alot of traffic during cruising in town, with no problems at all. Temp didn't get above 190 deg. A friend of mine builds race engines and told me my timing is set too low also. Will I ever get done? Not with a Mopar, but it's worth it!

[whtbaron]

I know you can buy that hose coil in different sizes because it's available for suction lines on ag sprayers as well. Maybe John can chime in on his automotive source. Glad to hear you're on the road... doesn't sound like the timing should be that hard to work out.

[John Kunkel]

I wrap stainless welding rod around a pipe to make my lower "springs". Never seen a recent source for them ready-made.

[whtbaron]

Searching around on Google one guy said he buys stainless steel wire at Home Depot and wrapped around some PVC piping. Here's a link but you'll have to sift through the Ford stuff to find out it's only 1.625" outside diameter which would be small for a lot of other cars. Someone else suggested they are available at Summit, but I haven't searched there yet.

http://www.cobraautomotive.com/catalog/engines.html

[whtbaron]

Some say NAPA has them if you can find a parts man smart enough to get it for you. Others are just buying the longest generic hose about the right size and pulling the wire out of them. If you do make your own, the hot tip is to bend a small loop at each end or the sharp end of the wire will eventually eat it's way out of the hose.

[John Kunkel]

You have to "tweak" each end of the coil or you'll never get it into the hose, the sharp wire ends will dig into the rubber as you push it in. Even with the tweaked ends you have to rotate the coil as you install it (depending on what size the coil is).

[whtbaron]

Oh yea...we're tweakin now!

[coupe32]

Just saw this post and wanted to put in my 2 cents. I had the exactly same problem and even tried several electric fans without a shroud. I changed radiator for a new Griffin. Changed water pump and thermostats. Nothing seemed to help. Well guess what it was an air flow problem at low speed. I finally talked to the guys at Walker Radiator and they looked at it and advised an electric fan/shroud combo. I bought a Cooling Components unit that pulled 2900 cfm. (Their newer one pulls 2700 cfm) This finally cured my problem and I am no longer looking at the temp gauge every minute. (never above 190) I think if you get a good electric fan shroud combo that pulls over 2500cfm you will be okay. I spent a lot of money on trial an error and it was just poor air flow. This was on a 340 engine in a streetrod. (If you buy just a shroud for your existing fan be sure the fan is spaced inside the shroud properly otherwise it may not help)

[cudanut jim]

I now have a shroud and a nice used 6 blade aluminum fan( not a flex fan) I picked up at the Mopar Nats for $5. I also installed an electric 16" pusher fan with a switch on the dash to use in case I get stuck in traffic and the temp. goes up. I also set the timing to 12 btdc at idle. I put a vacuum gauge to the carb manifold. It got up to about 20 on the gauge and could no longer see the timing mark on the crank, so I stopped it at about 12. Car runs with more power now and stays at around 190 deg. Done for now I guess, until another gremlin shows up, which I'm sure will. That's what happens when you drive an old Mopar, but it sure beats staring at it on a trailer!