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Technical mopar 318 running HOT, help!

Discussion in 'The Hokey Ass Message Board' started by jcs64, Jul 30, 2014.

  1. jcs64
    Joined: Apr 25, 2005
    Posts: 528

    jcs64
    Member

    Still working on the shroud, my arms look like I fell into a box of razor blades, lol
     
  2. daliant
    Joined: Nov 25, 2009
    Posts: 683

    daliant
    Member

  3. jcs64
    Joined: Apr 25, 2005
    Posts: 528

    jcs64
    Member

    Ok, the cars all buttoned up AGAIN.

    180 stat is back in and a new shroud is on.
    [​IMG]
    It didn't come out exactly as planned but it dosent look too bad. I was going to do four button head 1/4-20's on the top edge but the fan blade would hit the nuts on the two, on the outer edge. Oh well, Ill have to do something to "hide" the extra 2 holes.

    But more importantly, It seems to work. The temp was maintaining at 180* for a good 15 mins.

    I did find one spot on the core that seemed hotter so I grabbed my pc of paper and found this.
    [​IMG]
    [​IMG]
    A really small strip in the upper passengers side corner is now blowing back through the rad.
    Its only like a 1/2" by 4 " strip, but its still weird.
    I may need to trim the shroud back some more since the fan is still in the shroud a little deep. It was a tough thing to get right because of the tappered sides, since when I tried to cut it thinner (make the shroud more shallow), it would also open up the dia. . I aimed for the best of both dimensions , so for now Im leaving it as is.

    Thanks for the help guys,
    jeff
     
  4. Gerry Moe
    Joined: Jan 29, 2006
    Posts: 498

    Gerry Moe
    Member

    http://www.summitracing.com/parts/sum-381106/overview/

    Nice job not many people try making the square to round fittings. When you get in the mood to change it to get rid of the last of the turbulance use this shroud from Summit as a design, this is a pretty simple design for the average home fabricator. Keep the fan blades 1/2 in as you already know the results
     
    Last edited: Aug 3, 2014
  5. Ok You have been fooling long enough.
    first put in a 160. Back in the day all cars ran 160s in summer and 180s in winter. Used to be regular work to change them even up to the late 1960s. 160F is the basic spot where below which it is hard on the engines. (Stockwell Automotive Fundamentals)
    The rad is ok. How do we know that? Because at highway speeds you have absolutely no overheating problem. If it wasn't up to snuff the faster you drove the hotter it would get which is what happens with an undersized or blocked rad.
    You problem is at low speed , in traffic idling and when shut off. Lets address the last one first. This occurs when nothing is going on after you have shut it off. So we know it has nothing to do with fans, shrouds, etc etc. What causes a rad to push water out? The water boils. When water turns to steam its expansion rate is astounding. There is not enough room in the rad for the coolant if steam is being formed. So why is steam being formed when the engine is shut off? One would think the engine would already be cooling . However there are spots in every engine that tend to run hot and it is the constant flow of coolant that keeps them in reasonable temp range. Once the flow stops they heat up for a bit till the heat in general dissipates. The rad cap on the engine raises the boiling point. If you can prevent the coolant from boiling it won,t puke coolant (ever)Every pound in the cap raises the boiling point 3 degrees F. So a 10 lb cap brings the boiling point from 212 to 242. I would very first put a pressure test on your cooling system if it had rolled into my shop. I know it is all new etc etc but I would check that first. You would feel like a fool if two years from now you discovered the system wouldn't actually hold pressure for some reason. I would then if it is good start with a 17 lb cap and I would MAKE SURE it seals to the rad cap part. I have on occasion made a rubber spacer(s) to take up any potential slack and make sure the cap is building pressure and holding it. And I would use a brand new cap. That should take care of the shut off puke so I will stop there and see how it goes. And if you are wondering am I familiar with 318s ? "Is the Pope Catholic?
    don
     
  6. Spaghettijet
    Joined: Nov 21, 2017
    Posts: 6

    Spaghettijet

    Hi all, I've got a simular issue as described and perhap dolmetsch can comment further.
    318 gets very hot in traffic and slowly creeps up on hwy above normal. Put an infrared thermostat on the heads immediately after turning off left head is -bout 15 c hotter than right, so much so that the overheating indicator attached to the front of the heads after reconditioning has slid from its original placement. RHS head reading 82 c LHS hand 98 c. This has been going on for years. WHEN I SAY LHS AND RHS I mean when sitting behind the steering wheel.

    So what have I done, three different water pumps, two sets of c.ylinder heads, three different dizzy, two radiators, suck thru electric fans in shroud on 5 core champion radiator current.
    Edelbrock 4 barrel carby current. Block completely hot tanked and deoxidine scale removal, same for the heads, it gets so hot on the LHS that the mopar blue paint has changed colour after the last rebuild. It's fairly stock engine, Kb pistons zero deck height x heads edelbrock inlet manifold. As I have said it's always done this running hot one side even with the stock pistons and cylinder heads, has about 5 thermostats through it too. I have an inline water pump from summit that I haven't fitted yet to see if that helps.
    My question is about the head gaskets, the lhs has a large coolant bypass hole straight from the block to the head and out the front inlet manifold galley, whereas the RHS is blocked at the front and has the hole at the rear essentially forcing all the coolant flow to the rear and to return to the inlet manifold water galley via the cylinder head port to the front. I note BB mopars have equal gallery holes in their head gaskets. Is it conceivable that the RHS is that much hotter because the coolant flow direction is offset by the direct return at the front of the head and is different from that of the left water flow as described. Would there be any benefit connecting a 3/8 line between the cylinder heads at the back to ensure head at the rear of both heads can be equalised. Would there be a benefit in making a 1/4 return hole in the lhs head gasket to bleed stone coolant back to the inlet anifold or would this create not enough cooling at the rear of the block and head, having said that then why is the RHS coolant flow designed like this?
    Also done the radiator caps replacements, shrouds, mechanical fan in the past, was hoping last rebuild with proper and full block chemical clean out was going to work but alas it didn't, comments please
     
    Last edited: Nov 21, 2017
  7. 10B5RT
    Joined: Dec 2, 2017
    Posts: 4

    10B5RT

    Spaghettijet,

    I think you are on the right track but don't think the 3/8 line or 1/4 return hole is the answer.

    I think your issue is the head gasket. Wrong side or flopped over.

    The coolant holes you mention at the front of the block (to front of each head) are supposed to be covered (sealed) by the head gaskets on BOTH sides. This will force coolant to rear of block, up and through heads then to front of heads into front of intake manifold and out through thermostat housing to radiator.

    There is a youtube video I found of a 318 rebuild called "Garage34 - Small Block Chrysler 318 - Construction Video" Look at the head gasket and how it covers front water passage. Here is the link:


    Ed
     
  8. Spaghettijet
    Joined: Nov 21, 2017
    Posts: 6

    Spaghettijet

    IMG_0115.PNG Thanks for the reply Ed, I watched the clip, I had seen this one before, unfortunately they only show one head. So this is correct on mine and the temperature is ok on this side, it would be interesting to find a snap of the other side which is my offending side. I have searched the net and am unable to find a pic. I purchased the how to hot rod a sb mopar Book and it doesn't show anything either, perhaps someone may red this post and have a photo. I will look for my build photos and post also.
    Thanks for your comments, they re appreciated and helpful.
     
  9. 10B5RT
    Joined: Dec 2, 2017
    Posts: 4

    10B5RT

    Spaghettijet,

    I just took the heads off my '69 Dodge 318. The head gaskets are still stuck on the engine. The water port at the front of the engine is covered on the driver side and the front of the engine on the passenger side. Hopefully these photos will show. You can see round imprint the heads made on top of the gasket but the gasket does not have holes for the FRONT water ports.

    Ed
     

    Attached Files:

  10. Spaghettijet
    Joined: Nov 21, 2017
    Posts: 6

    Spaghettijet

    Thanks Ed, that's pretty conclusive, I am soon to take the heads of and replaced with alloy edelbrock units, so I will make sure they are same with the covering of the front holes
     
  11. Spaghettijet
    Joined: Nov 21, 2017
    Posts: 6

    Spaghettijet

    Hi Ed, I have began disassembly to replace heads with edelbrock alloy units, I checked the gasket of the heads and can confirm that both left and right sides have the water return hole covered at the front of the block on both sides. Attached is photos of each side of the heads, you can see that the right hand head has been running a lot hotter than the left hand side, as mentioned prior every conceiveable item has been carried out to try and resolve this issue that has plagued the car for the last 20 years. Any ideas appreciated.
     

    Attached Files:

  12. 10B5RT
    Joined: Dec 2, 2017
    Posts: 4

    10B5RT

    Spaghettijet,

    The reason I pulled my motor was because it was overheating similar to your issues. Its a long story I will try to make short.

    I got my motor 12 years ago (was supposedly running at the time, I heard it run once). I had it rebuilt by a local shop and when I got it back it had the heads and freeze plugs already installed. I finished assembling, installed, and finished rebuilding my car. For the last 12 years it has run fine but has had intermittent overheat issues. Like you, I replaced all cooling system parts at least twice. Used every bad word I know (I know a lot). Still unexplained overheating.

    So I figured it must be something inside the cooling passages. I pulled the motor and removed the freeze plugs from the block. There was some sediment (really hard stuff) in the bottom of the water passages with a couple of loose chunks of crap. This should have been cleaned out 12 years ago when it was hot tanked and rebuilt but I guess it wasn't. But I didn't see that anything was obstructing water flow. I removed the freeze plugs from the heads and they both looked clean inside.

    I then removed the heads (on Dec 2 and took head gasket photos for post above). I found that the main water passage at rear of right side (passenger side USA) was completely blocked. This is the big 3/4 inch hole in the block where water flows up to the head. There was just a little bit of crap in the other small holes but they were mostly clean.

    Then I tried to clean out the blocked hole. Finally poked a small hole through with a piece of wire but couldn't break a hole through with a small screwdriver. Attached photo isn't very good but shows blockage at this point.

    So I got a hammer and chisel after it. It turned out to be solid metal (not real thick) with what looked like a short piece of welding rod attached underneath. This was part of the casting mold/overflow when the motor was made and wasn't caught at the factory. And the rebuilder 12 years ago didn't inspect all the water passages either.

    This motor has had that main coolant passage blocked since 1969! Somewhere is a 90 year old retired Dodge factory line worker still laughing at whoever bought the car with that motor!

    After all this long story, my suggestion for you is to look down in all those coolant passages for anything blocking them. You might need to pull a couple of freeze plugs too. Got to be something on the hot side of your motor being blocked. Might even be something blocked in the head water passage.

    Good luck
    Ed
     

    Attached Files:

  13. Spaghettijet
    Joined: Nov 21, 2017
    Posts: 6

    Spaghettijet

    Thanks Ed, I will be removing the heads today and will be devising some means of checking water flow in each water jacket of the block. Will let you know what I find, although I do seem to remember I put the high pressure hose in every hole when I chemically cleaned out the block, but that’s not to say some obstruction still in there. I have also just purchased a fifth water pump kooler 1900 pump
     
    Last edited: Jan 11, 2018
  14. Spaghettijet
    Joined: Nov 21, 2017
    Posts: 6

    Spaghettijet

    Heads are off, no blockages, pulled the water jacket drain plugs out, put the water hose in the block deck water hole, free running water no gunk. Poked all the holes with long wire no blockages, I’ve got no clue as to why it’s running hot on the one side.
     
  15. R Pope
    Joined: Jan 23, 2006
    Posts: 3,310

    R Pope
    Member

    Air coming out the corners of the rad says that there isn't enough flow past the engine and out the rear. Hot air coming out under the front end points to the same thing. Have you tried running with no hood? I don't know if you even have a hood, pics dom't show on my computer.
     
    King ford likes this.
  16. 10B5RT
    Joined: Dec 2, 2017
    Posts: 4

    10B5RT

    Since every cooling component has already been replaced, and you already had 2 sets of heads on it, I think the problem is still in the water passages in the block.

    Can you buy or borrow one of those flexible inspection cameras? The kind that is small enough to poke through a spark plug hole. It should fit in some of the water holes so you can look inside. Then maybe you won't have to remove freeze plugs to see inside. Some freeze plugs can't be removed without pulling the motor out of the car.

    Keep in mind where passages should be because if blocked it may look normal. On mine there was lots of crap built up in the back where the oil filter is. I thought maybe that was normal metal but I kept cleaning and scraping and finally found there was only a small bump of metal. Not your hot side but worth a check.

    There is a small gap between each cylinder, easy to be filled with crap. Shine the camera light inside between the cylinders and look into the small holes from above to see if light shines through showing its clear (easier after dark).
    These 318s should not be having these issues. Super reliable, run forever, never overheat or give grief. I'm still putting mine back together but am confident it won't overheat any more. I'm in no hurry - it's cold here in Oklahoma and my garage has no heater.
     
  17. sedantudor
    Joined: Jan 28, 2012
    Posts: 57

    sedantudor

    A while back a buddy of mine had a 34 Plymouth with a 360 in it. We tried every trick possible to get the car to run cooler. The car would run between 205 and 215 degrees all day long. From what I have discovered that just seems to be how mopars like to run. To me that seems hot (especially since I am used to a SBC) but all the mopar gurus I talked to said that 215 was ok for a mopar small block. Car ran that way for six years without any issue. That being said, you could look into a flowcooler waterpump. My sbc in my 47 Ford had the a similar problem. I put in a high flow pump and the problem has pretty much gone away. It will still get "warmer" in serious traffic but it is fine at traffic lights and such. Just an idea.
     
  18. racerlall
    Joined: Mar 18, 2011
    Posts: 78

    racerlall
    Member
    from WA

  19. doug warren
    Joined: Apr 3, 2017
    Posts: 37

    doug warren

     
  20. doug warren
    Joined: Apr 3, 2017
    Posts: 37

    doug warren

    I know you went through the motor but maybe there is a problem with the head gasket or the wrong head gasket application. Bad head gaskets will cause you to boil over in a hurry. Also for shits and grins get an other mechanical temp gauge to verify the one you are using to see if the agree.They are cheap and it will verify your orginal is up to snuff. try putting a large box fan infront of the radiator while running and see if that helps cool down. Why didnt you use a mopar radiator, Just asking. Get the biggest most rows you can. Keep it simple.maybe cracked head or block. any water in oil? ok im out of ideas.
     
  21. doug warren
    Joined: Apr 3, 2017
    Posts: 37

    doug warren

    Does this thing run a fan clutch. I can get the photos to open. maybe fan clutch is shot. Also I had a 318 in my 82 dodge van and that thing always ran cool, even in the sw desert. Also I was told fan should be like half in and half out of shroud also. If not fan will start cavitating the air in shroud and reducing the movement of the air.
     
  22. doug warren
    Joined: Apr 3, 2017
    Posts: 37

    doug warren

    Just throwing it out there, could there be an air buble in one of the cyl.heads. Ive seen guys using a vacum pump on some of there cars to pull out the air in the cooling system so there is 100 % cooland flowing through the system. Also my wifes 93 camaro has manual bleed valves through out the cooling system to bleed air out at the highest point. My 56 chevy has a heater cor thats higher that the radiator and I was getting steam in there and man did it make a chunk,chunk noise. Weird thing is When I have to get into the coolant system I refil through the t stat housing on the top of the engine and that seems to get the air out. Ok my 2cents worth.
     
  23. King ford
    Joined: Mar 18, 2013
    Posts: 1,280

    King ford
    ALLIANCE MEMBER
    from 08302

    no pictures here either but it sounds like an air flow issue so I agree with taking the hood off and see if that helps!
     

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