HOT running mopar 360LA

[Plato2k5]

Just got back from Silver lake Sand dunes where my jeep ran 220+ if I were beating on it.

Been fighting this heat issue for years. Its a mild built mopar 360 with cast heads, around 10:1 compression, flat top pistons, cam, headers.

The water pump is a mopar performance and i think its the 6 blade so it says its made for drag race use...could this be my issue??

The radiator is aluminum with a electric fan and a shroud that covers the entire rad. The shop that built it says its good for 600hp and they put it on the jeeps with the Hemi conversions.

I changed the cap thinking it may be leaking. The stat is 180* and I even pulled it thinking it was sticking and ran a restriction plate. Still no change. Running down the road it will run at 195*.

Should i put on a stock pump? could the coolant be caviatating at the high RPM? Weld a plate to the back of a stock pump? or a plate on the back of the performance drag racing only pump?

My hood gets so hot you cannot touch it. So i'm also wondering if its just heat soaking? I have header wrap on the way. Also, the heater bypass hose is still connected...should I block it off and drill holes in the stat?

thanks!

 

[67cuda360]

what is your timing set at? If it is too retarded it will make the engine run hotter.

 

[Plato2k5]

Good question!

I put a light on it earlier today to see where it was and at idle with no vac advance its at or dang near 11. I do not run a vac advance since I switched to EFI I do not have a ported signal.

 

[67cuda360]

how much timing does it have when all your mechanical is in? (test at 3000-3500RPM to be safe)

 

[MopaR&D]

You say it's a Jeep at the sand dunes, I'm guessing that's a lot of extended periods of WOT going up hills right? If so this is putting a lot of stress on your engine and it needs to be able to get rid of the massive heat build-up as quickly as possible.

First what kind of gas are you using? You may want to try some race gas for a session and see of that makes a difference; do you know if the heads are LA or Magnums (closed/open chamber)? Also what's your ignition advance curve like? And what about the carb tuning (running lean causes overheating)?

If you could take some pictures and show us what your radiator setup looks like, it sounds like you might have it set up to be restricting airflow around parts of the radiator. You want to keep the increased flow of the 6-blade water pump as well, an 8-blade is more for sustained high-RPM use like circle track racing. What kind of RPM is your engine usually spinning as you're romping the dunes? A plate welded to the back of the impeller improves flow and reduces cavitation at higher speeds.

Lastly I'd think about adding hood louvers and/or hood scoop + cold air intake to let that under hood heat escape. And don't mess with the bypass hose or drill the stat that won't make a difference, just keep the 180* one in there.

 

[Plato2k5]

I have to test that. I do know at one time it was at 32 total. However I'm not certain I changed that.

How do you tell if the mark on the balancer only goes to 11? Tape? The guy who did it before for me had a fancy light with a digital readout?

 

[Plato2k5]

http://kirkbecker.smugmug.com/Off-R...20-12/23098178_Gm9vkQ#!i=1860079551&k=W3WKfjH for some pics of the jeep at the dunes.

I run hood louvers. I run a open intake as well. The heads are LA style that have pocket porting down and the bowl cleaned up.

I run 93 octane up there and yes as you can hear in the video I run it open a good amount of time...4500+ as I run 4 low. 4 hi or 2hi my trans will overheat from spinning the 39.5x13 inch tires.

 

[67cuda360]

you can put timing tape on the balancer (never really sticks well though) or use a dial-back timing light.

Have you tried upping the timing a little bit by maybe 4 degrees so that you have total timing of 36. Make sure it doesn't ping (if it does, back it off one degree at a time). Might help you bring the normal operating temperature down to 180.

MOPEkidD-3 has some great suggestions.

 

[67cuda360]

also 220 while working its *** off at high RPM isn't that bad, especially out in the heat with unwrapped headers and reduced airflow (not driving on the highway).

With the proper radiator cap and proper coolant mix the boiling point will be well over 250-265 IIRC. Cruising temp (195) is a little high, but some engine are just a bit more warm blooded then others. Consensus is that it is better to run a slightly warmer engine then a colder one (so stay away from the 160 degree stat won't solve any problems).

 

[Plato2k5]

So what would be a dangerous level of hot if 220 is OK? My gauge is a autometer and it really sucks with the numbering. you have 180, tick mark, 210, tick mark, then 250...so I don't know how accurate it really is. I'm picking up the temp from the aluminum intake. Also my fan kicks on at around 195 so I think that is why it runs there. ? Maybe lower the kick on temp??

 

[crackedback]

Search "hillbilly timing tape" and my user name...

 

[daredevil]

Are you sure you dont have belt slippage? In the video when you start it the belts squeal for 30 seconds.Maybe at high rpms the pulleys arent moving as fast as the belt.

 

[67cuda360]

I'm not saying 220 is a great temperature to run but in the conditions you are driving, hot sand with 4wd engaged at high RPM and those big tires with unwrapped headers on a hot day it doesn't surprise me.

Do you run a trans cooler? If not that would also add to your high temperature.

 

[Plato2k5]

hmm.... good point with the belt slip..... i only hear it at startup when its hot.... but i guess it could be slipping... how would you fix this? The belt is tight but not so tight it will wear the bearing out.

So is it possible that the radiator is soaking up the hot air from under the hood causing the coolant to stay hot??

trans cooler yes. I did move it from off the front of the rad and it made no difference. I also run a winch on the front which I assume is a big restriction. Wonder if a pusher fan would help along with the puller??

 

[67cuda360]

I have one of those infrared temperature readers, pretty handy to have and great to check what the true engine temperature is. You can point it at different locations and hoses to get accurate readings.

Here is the one I got but I got it for 60% off

http://www.canadiantire.ca/browse/p...T<>prd_id=845524443296845&bmUID=1337647988201

 

[Plato2k5]

nice hillbily timing tape! i'll do that for sure. thanks!

funny you mention the IR gun... I actually had that with me in my toolbox. DOH! Why didn't I think of that

Just sucks I have been chasing this darn problem for over 5 years. Finally thought the radiator cured it.

 

[Plato2k5]

oh and I don't know if my bottom hose has a spring.... so maybe its collapsing?

 

[MopaR&D]

I noticed you said the fan "kicks on" at 195*, one thing you might try is wiring a switch to the fan so you can turn it on manually and leave it on when you're driving hard.

I looked through the pics and you don't have any underhood ones, any chance you could take a pic of the radiator/fan setup? What may be happening is the shroud is covering up parts of the radiator and restricting airflow; also the electric fan may be mounted too close to the fins which also restricts airflow. You are putting the engine under high load without much speed so getting sufficient airflow through the radiator at low speeds is critical. I might even argue in this case that a belt-driven fan would work better than an electric one because the fan speeds up along with the engine and pulls extra air as the RPM rises.

EDIT: Lower hose spring might be a good one to look into as well, it might be collapsing when you hit the gas...

 

[Plato2k5]

Ill take pics after work. Can't use a mechanical fan because I had to offset the engine 4" to the passenger side to clear front drive shaft on the 727 pan.

I use to have a manual switch for the fan but took it out thinking this radiator would cure my problems. Ill wire it back in.

 

[moper]

What are the ambient air temps when you're running around in the sand?

 

[Plato2k5]

I do not know...hot enough where you can't hold your hand on the hood as its so hot. The louvers vent a ton of hot air.

 

[Plato2k5]

 

[Plato2k5]

what size pulley should a NON A/C engine use?

what size pulley should a A/C engine use?

My pulley is a 2 belt, and is over 6" in Diameter.

 

[moper]

I do not know...hot enough where you can't hold your hand on the hood as its so hot. The louvers vent a ton of hot air.

The surface temps are more a result of the sun than air temps. Ambient air temps will tell me how hard the system is working to maintain running temp.

 

[Plato2k5]

All I know is you can see the heat waves pour out if the louvers. It can be a cool day and the hood heats up quick. I can't work it hard enough here to get readings and next dunes trip is in June...I hope to have this fixed before then. I'm going to buy a flowkooler pump as stock part stores are around $60.