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V8 cooling issue
V8 runs hot when flogging it. i think the water pump may be cavitating ata higher rpm. in traffic it runs 185 for hours. at 70, 200, over 85 it will over heat 250+ if driven like that for 20 minutes. at the AX it gets to 230 is 3 laps. radiaator is huge, airflow is ample. no trapped aiar. has anyone seen this before?
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Sean
I would say look at the thermostat,water pump and check out all your hoses and so forth especially if it has just started happening! If all those items check out good the head gasket would be my next concern.:eek: |
Sean,
Pictures of your installation would help in troubleshooting. Without seeing it, I'll offer these: 1. Change thermostat out and replace with the Mr. Gasket "high flow" unit. It looks different than anything else out there and does flow more water when open due to its design. Available at Summit and Jeggs. This was the cause of my problem when first running my car in the Georgia heat. I tried several run of the mill t/s's until finally trying this one. 2. Check your hoses for possible kinks. The most common area is at inlet to water pump (this is about the tightest turn in the system). If you see a partially crimped section, try to eliminate by inserting a steel spring in this area to eliminate collapse at high rpm. The next most common area for kinks would be the two hoses exiting pump and running to block. Hard to see when installed in car but you can check by using mirror or feeling entire line when cool. 3. I've heard that a 50/50 mix of antifreeze/water does not cool as well as when running with less antifreeze. Pretty cheap and easy to try. You could drain two gallons of what your running and add fresh distilled water, purge system of air several times and see what happens. This would be a good time to use a flush kit as mentioned above. 4. You may have a damaged water pump impeller (pitched a blade) if you run a thermostat without addition of bleed holes. The bleed holes releave pressure at pump (protect impeller) while thermostat is closed. Renegade warns against operating engine over 2000 rpm until it begins to warm up.........this is without the bleed hole mod.. Checking for a thrown blade would be the last thing to try due to the level of effort required to disassemble pump. 5. You mentioned no air in system. What are you running for a recovery tank? Does the level in tank return to the same spot after a full cool down (overnight)? If not, your loosing water somewhere. If your sure there are no external leaks, it's time to test with pressure. Rent a cooling system leak tester and attempt to run down source of engine leak. Double check for external leaks with leak tester prior to checking anything else. As mentioned earlier, the hoses at front of engine cannot be seen very well. Check this area good while at pressure. A blown head gasket or leak between intake to heads are the most common. A chocolate milk colored film on dip stick would indicate a on going leak of system. I have seen internal leaks that did not show this milky substance on dipstick.........probably due to the leak being new. If you can't hold pressure on test device (20 lbs. for 10 minutes is what I remember as a good test), you could drain oil from pan and pull all spark plugs. Leave drain pan plug out and again pressure test system. Water seen coming from oil pan plug or any of the cylinders would help pin point problem area. 6. A different rated pressure cap is easy to try. Renegade recommends a 16lb. cap for their system. If your using another cooling system, you'll just have to experiment. 7. Backing off timing is worth a try as mentioned by someone else. 8. Have you ever had air/fuel ratio checked? A lean mixture may cause engine to run hot. I had mine tested while on dyno to verify ratio was right throughout rpm range. Is this something that just came about and have you operated car at your current ambient temperature before? If it all of a sudden occured, I'd go after thermostat and a pressure test. Where is water temperature sender located? (heads, block, intake, other) How dependable is your temperature measuring device (gage)? A second gage and sender is recommended. Are you sure your water pump belt is not slipping? Provide the diameter of your water pump pulley. There seems to be a couple different sizes being sold for conversion kits. The smaller one would provide more flow. Are your water hoses routed in longs. or down center of chassis? What size is your inlet to radiator? My hole is measured at 4" x 20" (80 sq. in.). It is recommended to have twice the outlet size as compared to inlet. Is the radiator sealed with a shroud? ie, inlet and outlet provide forced air through radiator and not allow air to escape through openings at any side, top or bottom. A indicator of fan status is recommended (on/off light). The fans don't do much good over 40mph but you want to make sure they are cutting on when speeds are lower than this. You want to make sure fans turn on at about 175-180F as measured at radiator. You could have a situation where fans turn on too late and the system can never catch up. Which water pump are you using? The Simpson is rumored to have a smaller inlet to pump as compared to what Renegade sells. That's about all I can offer this early Sunday morning. Just as a comparision, my car runs @ 170-180 in traffic and about the same at sustained highway speed at 80 mph. With the recent addition of a/c, my in town temps. will go to 200F with near 90F weather, with highway temps. remaining at 170-180F. John |
Wow, this is some good information. I am doing my conversion now and this will be great for when I get it done. Hopefully I wont have these problems. I opted for the Rod Simpson radiator kit complete. It was about $150 less than the renegade setup. The rest of my conversion parts are from Renegade however. I have seen Seans radiator. I think he should change it out for the aluminum ones used by Rod Simpson and Renegade. They are very efficient and small. I must say though, installing it was a little more difficult than I had thought it would be. I spent most of the day yesterday cutting the holes for the flow. Because it is a Chalon I have so much space between the spoiler front end and the body where the hole is cut, I am making sheetmetal to enclose the openings to channel the air directly into the radiator and it will be completely sealed. Hopefully that will help channel the air directly to the radiator. This is a great thread and I will be using any and all information I can get on this subject in hopes of eliminating any problems. Thanks all.
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great info indeed. I think the high flow thermostaat will do it. I floggeed it hard all day ata teh track today . we had just enough time in teh grid before each run for it to drop into the saafe zone. I'll post pics asa soon as I fix my house computer where teh pics are stored
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Guy,
The bleed holes in thermostat follow the same principle as a bypass designed in the stock GM, Ford etc. water pump. I'm not sure if the original concept was to prevent cavitation or other pump related problems. In our converted cars, the bleed holes will also prevent blowing a hose off while in the same mode (t/s closed, pump spinning above 2000 rpm). John |
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The method you describe above will work in providing heat for cabin but won't perform the same function as drilling holes in t/s. Tapping into suction side of pump with one hose and the other connected at intake will still hold pressure until t/s opens with our style water pump. You would be providing water to heater core but until t/s opens, the water going back into intake is dead headed. The ideal method of providing water to heater core would be to use tap in intake as supply to core and tie in return from heater core in any location of supply line to water pump (from radiator exit point up to inlet to pump). Intake port is pressurized where the pump suction side is not......well, very little until system is at operating pressure. You'll also need a valve of some type intalled in supply line (to heater core) to prevent having heat on all the time. John |
Kragen, auto zone and Flaps all sell Milodan hi flow thermostat #16400. I paid 11.95 at Kragen
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All,
I'm getting close to starting on my V8 conversion, and had a question about the opening for the radiator at the front of the body/bumper area. Can anyone post a picture of this cut out and/or provide a size and location? It would be very helpful. Also, is any bracing or strengthening required adjacent to this cut out? Thanks, Andy |
Andy,
I don't have measurements, but the attached pic should provide what you need. No added bracing is required. John http://forums.pelicanparts.com/uploa...1084318993.jpg |
Bumper opening is 4" x 20". You should have twice this size for air to exit front trunk. http://forums.pelicanparts.com/uploa...1084319391.jpg
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a little more detailhttp://forums.pelicanparts.com/uploa...1084319754.jpg
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Cleeeeeeaaaaaannnnn....
I actually would consider an "X" brace across the opening, made of narrow tubing. Seeing a hole that size would make me a bit nervous. Ditto the wheel well openings... Maybe a single diagonal tube? Hmm. I'd have to do a whole lot of thinking about it first, as I'm not that familiar with what actually carries the loads in the front trunk other than the floor pan. Right now, I'm just reacting to the look. --DD |
John2kx,
Thanks for the pic's!! Is the cutout opening area greater than the 4"x20" opening in the bumper? It kind of appears that way. I should know this from your previous posts, but this looks like an RH radiator set up; correct? One more request: What are the dimensions of the RH radiator cooling area (area not including the tanks)? Yes, I agree. A nice clean set up!! Andy |
Guy,
I'd like to see pics of your install. My design is actually the way Renegade is currently doing their installs. I went to Vegas and viewed their facility prior to performing the operation. I'll be honest, the wheel well openings were a concern to me as well but after seeing a couple of the RH converted cars that were driven on a regular basis, my mind was at ease. Scott runs about 100 more horsepower than I and also uses his car on the track. Thanks for the compliments but I'm sure it would not have turned out this way without doing the Renegade factory tour. I took about 100 pictures and viewed them many times while putting my car together. I copied Scott's car in just about every aspect vs. trying to reengineer. I figured the guy who owns the company would be a good person to follow. The 6 hour tour consisted of viewing all the conversion parts, completed cars, builds in progress, cars with and without a/c and a couple of different ways of doing this. A 914 was raised on a lift to view areas I had questions about. I must say the education and photos allowed me to put my car together with confidence. John |
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Yes, the entire conversion was provided by RH. The area you asked about is much larger than the 4"x20" opening in bumper. I'll get you some dimensions in the next 24 hours or so as my front trunk is full of interior parts right now (another project in the works) but I'll try to describe the openings for you. The radiator is the largest piece in the puzzle. The shroud is the same size as radiator as it attaches at front of radiator. The shroud reduces in size as it is mated to opening in front of car.......and then the smallest opening is in bumper. John |
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http://forums.pelicanparts.com/uploa...1084423333.jpg
air exits under teh car and haas an 18 'inch fan I installed teh high flow thermostat, moved the teemp sensor from the thermostat housing to the intake manifold, added a straighter hose from thermostat to the expansion tank. these things made a small improvement but I dont have enough room on teh street to push it hard enough to reaally know since symptoms only show after long term flogging on the track or on a long road trip to AZ. pipes to teh rad are 1.25 inch |
one smaLL HOSE goes to the bypass flow in teh intake manifold. the other one comes from the highest point on the rad. it purges it's self, no air burping required. note the tubular aluminum engine bar mount. does anyone recognize this water pump?
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Need better pics of the water pump. The one i am putting in mine is a Renegade, in fact most of the parts are Renegade. The radiator I got from Rod Simpson and the pilot bearing will come from Kennedy. I called Rod Simpson first and he wanted 40.00 for the pilot bearing and when I showed him my flywheel he said his wouldnt work. So I called Renegade since it is their kit and they want 75.00 for the pilot bearing kit. I called Kennedy and they told me the pilot bearing is not specific to the flywheel as it is pressed into the end of the crankshaft. They sell the kit for 20.00 so its coming from them. I will order it tomorrow. Amazing what you find out when you shop around.
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Guy,
I like your design. You should have no problem with airflow to radiator and the additional bracing looks great. Thanks for the pics, as they sure clear things up. John |
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I looked at the Milodan t/s (#16400) and it is the same as what I'm using packaged as a Mr. Gasket part. But, there is room for improvement to your system based on the pics you posted. Your expansion tank "appears" to be missing a critical piece necessary to keep air out of system. If you don't have another tank that your expansion tank can overflow to, you'll introduce air into system when engine cools down. In other words, when the water temperature approaches 150F, water will expand. This combined with pressure building in system will cause relief valve in radiator cap to lift and allow water to escape. If your expansion tank has a line that dumps excess overboard (no catch tank), this is where the problem starts. Instead of the vacuum pulling water back into system during cooldown, it will draw in air. This may be the source of your overheating problems. If you have a overflow tank, disregard everything I just mentioned. More pictures would clear things up (water pump, better view or descrition of how hoses on expansion tank are routed). I don't see how you are "bypassing intake" with one of the small hoses on expansion tank routed to intake. Unless this hose is connected down stream of thermostat (t/s housing or return hose to radiator), it is just connecting tank into top of intake manifold. I've seen alot of converted cars but have never seen anyone run a separate line from top of radiator to engine bay as a means to remove air. Maybe this will work but I've never seen it done before. I'll post a few pics of stuff I have seen work in the past few years. When I say work, I mean cars with several thousand miles on them running 400 hp small blocks in the Georgia heat without cooling issues. Not to say there weren't cooling issues at the beginning, but the problems were identified as we learned and problems corrected. Johnhttp://forums.pelicanparts.com/uploa...1084453700.jpg |
The orange car belongs to Bob out of Athens, Ga. He has designed his conversion himself and his cooling system works. It was originally put on the road with a electric pump but this did not work.
If you look at his side by side tank, the one of the right is essentially what your running in your car. The tank on left is what is missing from your system (if in fact the clear line at top of your expansion tank dumps overboard). John |
This is how water expansion is controlled in my car. Clear hose goes to inlet fitting on bottom of expansion tank. Black hose is overflow to ground. Note: with about 1" of coolant in clear expansion tank from a cold start, tank level will increase about 2-3" if it is hot outside and really run hard. It takes several hours for the entire system to cooldown and vacuum effect to pull contents of expansion tank back into cooling system. This is also a good way to monitor for leaks. The level comes back the exact starting point when allowed to cool overnight. http://forums.pelicanparts.com/uploa...1084454420.jpg
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Oh this is great, I am getting more free information and learning. Great pictures guys, and thank you for passing your knowledge on so others can see and learn.
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Entire radiator is 28-1/2" wide x 13-15/16" tall Fin area is 26-3/16" wide x 12-3/4" tall John |
Guys, thanks for all the pic's and info!!
John2kx, the radiator fin area is significantly larger than the area of the opening in front. BTW, the general rule for the exit area is 1.7 times that of the inlet area, though there are a great nimber of things that would influence this especiallly in something like the 914 conversion. I think using the undercar intake as a suppliment to the frontal intake would be a great advantage....interesting. Andy |
Speaking of cooling systems I have been able to purchase a couple of C&R nascar take off radiators. The one in the picture will fit in the front trunk of a 914. It needs to set at a different angle than the RH radiator due to the larger size. These rads. are 4 to 5 inches thick and some come with built in oil coolers. They are all double pass with 2 1.25 inch 21 fin/per inch cores These come from a top 5 nascar team.
I've got a set of 12 inch cooling fans and will make a full aluminum shroud for them. Im thinking of making a kit with all of mounting hardware and hose,surge tanks and overflow and try to sell it as a kit. Wondered if there would be any intrest it them??http://forums.pelicanparts.com/uploa...1084478428.jpg http://forums.pelicanparts.com/uploa...1084478498.jpg |
Sean,
Bob's hardware should take care of your cooling issue if the little things suggested do not work. If that thing can cool a 750 hp Nascar engine with the small inlet hole they typically use, it should be overkill in our cars. John |
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Andy |
They also do alot of drafting with almost no forced airflow.
The core is 26"x15". There is a big difference with the speedway radiators and the short track ones. The shop I got this from had about 50/60 radiators any size or shape. Last summer in 95 deg. heat I ran my car with different size air openings. I taped over the inlet and ran from idle to freeway speeds to see how small of a opening I could get away with. The results suprized me. On the next car I'll start with a smaller opening and go larger if needed. Bob |
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Bob, nothing like good old fashioned testing to confirm results!! My experience with roadrace stuff, is that with good air flow management, the radiator can be downsized quite a bit (saving the weight of the radiator and the extra water. With the 914, you basically have what you have; therein lies the challenge. BTW, I like your NASCAR take-off idea. Cheers, Andy |
[. BTW, I like your NASCAR take-off idea.
Cheers, Andy [/B][/QUOTE] The best nascar take off. The shop takes older SB2.2 engines and converts them for the street with lower compression 11/1 and no restrictor plates. Dyno's in the 650 to 700 hp range. Bob http://forums.pelicanparts.com/uploa...1084570510.jpg 355 – 360 cubic inches Compression ratio 10:1 runs on “pump” gas Block: Chevy BowTie, 4 Bolt Mains, Splayed Billet Caps Pistons: Forged Aluminum Alloy, J&E or equal, Bore 4.125 Crank: Billet Sonny Bryant, Stroke 3.335, 37-45 lbs. 2.0 or 2.1 rod journals Rods: Carrillo or Lentz 6.20” H beam. Carr Bolts ATI Balancer Heads: 18 Deg. CNC Ported Aluminum Chevy Cylinder Heads w/2.150 Titanium Intake Valves, 1.6000 St.St. exhaust valves, Comp Cams triple valve springs, Titanium retainers and keys, Copper Berylium Valve Seats, Heads Flow 330 cfm @ .700 lift. Cast Aluminum Chevy Valve Covers, personalized for owner Jesel shaft mounted roller rockers 1.65 ratio Cam: Competition Cams Solid roller, 110 Deg. Centerline, Lift= 605 intake and exhaust, Duration 300 intake and exhaust Lifters: Competition Cams true roller lifters Wilson Intake manifold and Tapered 4 Hole Spacer 2.00" Part# 004150 Quick Fuel 750 cfm “Street Carb” Oil System: wet sump: Milodan Internal Pump w/ competition sheetmetal pan Oil System: dry sump, external pump Barnes or equal Specifications subject to change (typical specs. may be adjusted for customer requirements) |
do you think thata engine would be easy to drive on teh street. the best part about my v8 car is that it is better than a 4 banger in every waay thata is imortant to me. less noise, easier to drive in traaffic anad haas power to spare. 650 SBC ponies might not be as user friendly. afater taking the car to the track for 2 days, I could see thata ana inexperienced driver could hurt himself or others with 650 hp on the street.
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No I don't think it would make a very good engine for a street 914. Not to mention the price for one of these ($12/15K) you could get 3 or 4 LS1/LS6 engines. Which I do think would be the ultimite 914 powerplant. Bob |
the "A" is sticking on my key boaard
I haad to go baack anad read page 2 of the thead. I paasted it all into a word document fro reference or to share with the next V8 914 rookie John: thankas for explaining the overflow taank function. I do have anaa over flow tank. it is mounted 12" lower thana the expansion tank (bad?) Towaard the rear of teh heads where the intake flanage mounts there are two small waater passages, I use these to alaow small amaount of flow even when thermostat is closed. I learned this back in my V8 Vega days. since it is a high point in the cooling system, it pushes the air out and into the top of teh exp tank. my car does not get hot in traFFIC (low flow air and water) it only gets hot when I romp on it real hard or keep the rpms up for 20-30 minutes thanks guys, i'll post more pics in a bit |
LS1 yum yum! I wouldnt mind converting to modern FI.
Guy, I am still going to finish building the Adriaatic blue v8 car. are you running yet? |
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