Breaking up, falling flat, pop & sputter above 5,000 rpm, & overheating

[superbee_68]

All those parts, a 509 cam, on a low compression engine, and valve springs never checked on stock heads. I don't get it.

All the "shiny" expensive parts easily swap to a 500 cubic inch stroker motor. The cam was laying around and took an extra 2 hours to throw in while the motor was out. There was tons of suspension work, frame connectors, cage, dash modifications, small block to big block swap, fuel system, wiring, etc. The idea is to get the car 100% functioning and driving on a "nearly free" low horse power motor, then throw in the monster engine next year. It makes sense to me, solve all the gremlins and issues (for example, over-heating) before putting an expensive motor in it. It's not the exact path I would choose when building a car but it nearly worked for the PO.

I agree with you though, throwing in that high of a lift cam on stock springs was a major oversight... Luckily the rest of the car was put together very well, especially the wiring if I do say so myself.

 

[superbee_68]

I feel pretty dumb right now. I turned the rev limiter down to around 4,200 rpm, and setup one of the digital displays on the dakota digital to read the engine rpm, and made a quick pull. As soon as the digital readout hit 4,200 rpm, the rev limiter kicked in and power fell flat, and I got the same exact pop and sputter, just a bit more intense than when it was set at 6,000 rpm. I have never strung my cars out that high I guess so the rev limiter is a new thing for my ears to hear. I am thinking it was the rev limiter the whole time, especially because the car hit 4,200 in less than a second punching the throttle in 1st gear.

I have come to the conclusion that this combination of stall and gearing gets the rpm's up there super quick, and the car was just hitting the rev limiter. I am going to take everyone's advice and change the valve springs, as cheap and easy insurance, and it's the right thing to do on a 509 cam. I was also thinking about changing the push-rods as well, another cheap and easy failure point to eliminate.

Just need to figure out the over-heating and the car will be ready for the track. Two 11" be cool fans with 1,400 cfm a piece are on the way, which should double the airflow. Any thoughts on running a gutted thermostat vs no thermostat at all? And is 35 gpm enough flow to keep a big block cool?

 

[5.7 hemi]

You need 4000 cfm minimum to keep it cool!

 

[Garys1969RR]

Limit your distributor to have only 16 to 18 degrees of mechanical advance. Set initial timing at 20 degrees, and total advance at 36 to 38, all in by 2000 to 2500 RPM. Retarded timing will cause it to overheat, and 20 total is definitely retarded timing. You are losing power with that limited amount of timing. Most of the gasses are burning in the ex pipe, rather than in the combustion chamber. This causes overheating. Remove the thermostat completely. Do all this, and that should make it run nice and cool.

 

[superbee_68]

Limit your distributor to have only 16 to 18 degrees of mechanical advance. Set initial timing at 20 degrees, and total advance at 36 to 38, all in by 2000 to 2500 RPM. Retarded timing will cause it to overheat, and 20 total is definitely retarded timing. You are losing power with that limited amount of timing. Most of the gasses are burning in the ex pipe, rather than in the combustion chamber. This causes overheating. Remove the thermostat completely. Do all this, and that should make it run nice and cool.

I definitely had the timing numbers posted wrong, I went back and corrected. 16 initial, 36 total, so 20 degrees built into the distributor. And you say loose the thermostat completely. Worth a shot.

And is 4,000 cfm really necessary? I don't think I can buy a fan combo with that much air flow. And I definitely can't run a mechanical clutch fan, need the electric fan and water pump to cool the motor in the pits between rounds.

 

[Garys1969RR]

Do you know how many miles the motor has on it? If it was re ringed with new bearings, it may take awhile to loosen up. Some new builds have a tendency to run warm until broke in. You may also consider richening up the main jets a few steps. That can help it run cooler, especially if it's too lean already. Keep us posted!

 

[superbee_68]

It had around 70,000 miles on it, bearings and rings are factory. The cam swap was the only internal work done to the motor. That's one of the reasons why I advertised the low compression numbers. So I don't think a fresh build running hot is the case here.

I've been doing some reading, and I am thinking I may need to drain the 50/50 antifreeze mix and run straight water with an anti-corrosion additive/water wetter. I definitely think the fans need an upgrade as well, they feel very weak compared to be cool fans in my superbee.

 

[451Mopar]

Valve springs and pressure check the cooling system, may have a bad head gasket causing the overheating, or maybe air trapped in the block? having any loss of coolant?
I'd also put a real thermostat back in it.

 

[5.7 hemi]

The Lincoln or Tarus 2 speed electric fan puts out over 5000cfm, will cool anything, but, you better have your electrical up to snuff. Look it up.

 

[Mike67]

Radiators are designed to have a certain ammount of water flow at a certain rate. If you remove the t stat completely you may compound your problem.
The stat served 2 functions, one to get a car up to operating temp in cooler weather, two, to restrict the water to allow it to spend enough time in the rad to properly exchange the heat build up. JM.02

 

[Garys1969RR]

Mine always ran cooler without the T Stat. It would get up to the cool side of the temp gauge and stay there. Best to experiment and see what works for your car. Once the motor overheats and boils over, then the problem gets worse. So I like to run without the T Stat to prevent this on a car that's having over heating problems. Once you get the prob solved, then you can maybe put in a 165 degree T Stat to help the engine get up to operating temp. Also, if you are running a high compression ratio, heat is your enemy. The hotter it gets, the more prone it is to pinging and detonation. That's another reason I removed my T Stat, as I was running 13 to 1 C/Ratio. And it ran great on the street with 98 octane fuel.

 

[PurpleBeeper]

I've hears a lot of people talk about "coolant dwell time in the radiator" is needed, so you need a thermostat. HOWEVER, both my Road Runner & Mustang run noticeably cooler (mechanical gages on both) without a thermostat. So, I'd say try it without and see what you get. It will only cost you a thermostat gasket and 20 min.

Also, distilled/de-ionized water + "water wetter" definitely reduces engine temperature. I work in an automotive laboratory and I've tested several brands personally. One thing I found is that actual Redline Water Wetter doesn't have very good aluminum protection. Royal Purple's Purple Ice points this out in their sales literature and what they say is true based upon my lab testing. With iron heads, you can use Water Wetter, Purple Ice or Lucas Super Coolant (mixed only with distilled/de-ionized water) no problem. If you have aluminum heads, stay away from the Redline Water Wetter. And here's a couple insider's tips..... Royal Purple & Lucas are EXACTLY THE SAME FORMULA (just different dyes) and Hyper Lube's product (the yellow one) is only soapy water with dye and provides ABSOLUTELY NO corrosion protection....Hyper Lube is snake oil.

 

[Cranky]

I've had the 'displeasure' lol of tuning on two different very low compression engines that liked a lot more timing that what you have. The first one made me distrust the timing light and the balancer and after trying two other lights and double checking the indexing of the balancer AGAIN, I was convinced. Anyways, if it's running good, then leave the timing alone unless you want to experiment some however, I wouldn't do anymore running with it until you got some decent valve springs on it. You don't want to swallow a valve. If it did that, all the fun would go away! I kinda like playing with stuff like this but ya don't want to kill it. It's something you don't mind leaning on hard in getting it to do things that many can't do with better engines. Thing is, don't kill it because of dumb stuff like sub par valve springs.

 

[superbee_68]

Dakota Digital is telling me I need an MSD tach adapter, part # 8920. Seems pretty silly to take the digital MSD tach output, use the adapter to change it back to analog, then the Dakota Digital changes it back to a digital signal to display on the gauge and digital readout. Guess I'll order the part.

I ordered valve springs, pushrods, and two 11" Be Cool fans (1360 cfm a piece) yesterday. The two 11" Be Cool fans on my Superbee keep it cool in this Texas heat, so I am going to give it a shot. When on the phone with Be Cool, the tech department also mentioned that the cheap Chinese radiators do not cool as well, even though they are the same size. The tech department recommended using a leaf blower to add extra airflow over the fans I have now to see if the car stays cool to verify an airflow issue, otherwise, he thinks the cheap radiator is the problem. I am also going to ditch the anti-freeze and run distilled water with a water wetter, should lower 3-5 degrees according to Be Cool. I will report back what I find out.

 

[Mike Gaines]

Your overheating problem is the Electric Water Pump. I have an Meziere Electric Water Pump on my 505" that runs 10.30's @ 129+ in the 1/4 mile.....BUT....I installed the electric water pump so I could "cool" the motor in the staging lanes (between rounds) with the motor turned off. ( I also have a big Be Cool Radiator and twin electric fans.) I launch at 150 degrees and it hits about 190 degrees going thru the traps and then climbs to 200-210 degrees driving back down the return road to come back to the staging lanes for the next round. I shut the motor OFF and run the electric water pump and electric fans and the motor cools down to 110 degrees in about 5 minutes......Your problem is that the electric water pump IS NOT MADE FOR STREET DRIVING. It pumps only 35 gal per minute (at one constant speed). The stock belt driven water pump out pumps that electric pump BY A WHOLE BUNCH because the higher rpm's driving down the road the stock belt driven water pump is pumping a whole lot more than 35 gal per minute.
My car is licensed and street legal and I drive it to a car show in town every once in a while BUT MY Meziere electric pump is rated at 50 gal per minute and WILL NOT COOL MY CAR for any extended drive time....

 

[superbee_68]

Your overheating problem is the Electric Water Pump. I have an Meziere Electric Water Pump on my 505" that runs 10.30's @ 129+ in the 1/4 mile.....BUT....I installed the electric water pump so I could "cool" the motor in the staging lanes (between rounds) with the motor turned off. ( I also have a big Be Cool Radiator and twin electric fans.) I launch at 150 degrees and it hits about 190 degrees going thru the traps and then climbs to 200-210 degrees driving back down the return road to come back to the staging lanes for the next round. I shut the motor OFF and run the electric water pump and electric fans and the motor cools down to 110 degrees in about 5 minutes......Your problem is that the electric water pump IS NOT MADE FOR STREET DRIVING. It pumps only 35 gal per minute (at one constant speed). The stock belt driven water pump out pumps that electric pump BY A WHOLE BUNCH because the higher rpm's driving down the road the stock belt driven water pump is pumping a whole lot more than 35 gal per minute.
My car is licensed and street legal and I drive it to a car show in town every once in a while BUT MY Meziere electric pump is rated at 50 gal per minute and WILL NOT COOL MY CAR for any extended drive time....

Mike Gaines, it's not a street car. And please don't take this the wrong way, I really do appreciate you sharing your setup and how it acts at the track. It will definitely help me figure out my overheat issue. But, it's got a 3 speed with 4.88 gears, a spool, 3,500 stall, manual valve body, no heat or a/c, no interior, etc. It's definitely built for the track with the current drivetrain, and I have been testing it for track conditions. And it's an extreme over heat issue. If I was at the track, it would be pushing 200 degrees after I did the burn out, especially down here in Texas heat.

I've been running a small block fox body Mustang this season with a factory radiator and single small fan that more than keeps up in the staging lanes, so I am very familiar with electric water pump and fans at the track in a proper working setup. I know it's apples to oranges, but I know an electric water pump and fan setup can work at the track when each component is sized properly.

I don't discount that the pump could be the issue, maybe this setup needs a higher flow rate pump, but I promise street driving is not my problem. With the help of this awesome community, we will get this over heat thing figured out. Since I ordered the fans, I'm going to start there. I think the cheap Chinese radiator will be my second part to replace if the fans don't work, then upgrade the water pump last.

 

[splicer]

Just to pass along my experiences....... I already have the 500+ monster and after trying cheap aluminum rads, various combinations of puller/pusher fans, thermostat/no thermostat, and different pumps, the system currently in the car is a BE-COOL 1000hp module with twin 13 inch fans, a 180 thermostat, Mopar performance mechanical pump, and upgraded Powermaster 150 amp alternator. This system works very well even in traffic, never exceeding 190 Deg
I think you'll find the rad you have won't cut it and you'll be talking to BE COOL again. Also a 55 gpm pump may be in order.
The rad in my B-body sits on top of the frame rails. The car makes 526hp at the rear wheels FYI
John B.

 

[Garys1969RR]

Here's a bit more to chew on. LOL. We have a 496 big block (383 block with a 4.25"stroke) in a 68 Valiant. Fully tubbed, Ford 9" rear end, Powerglide trans. Full roller motor. Roll cage, strip only. It has an alum water pump, alum radiator, electric fan. Well it overheated at the track after the second pass, after doing the burnout for run 3. Catch can boiled over, water on the track etc. Had to put it out of the staging lanes to let it cool down. So you're not the first!. It was 95 that day, though!

 

[Cranky]

Here's a bit more to chew on. LOL. We have a 496 big block (383 block with a 4.25"stroke) in a 68 Valiant. Fully tubbed, Ford 9" rear end, Powerglide trans. Full roller motor. Roll cage, strip only. It has an alum water pump, alum radiator, electric fan. Well it overheated at the track after the second pass, after doing the burnout for run 3. Catch can boiled over, water on the track etc. Had to put it out of the staging lanes to let it cool down. So you're not the first!. It was 95 that day, though!

Any particular reason y'all used a 383 instead of a 400 block?

 

[Garys1969RR]

Any particular reason y'all used a 383 instead of a 400 block?

I bought the car with the 496 in it already. I thought it WAS a 400 block at first, until I saw 383 stamped on the ID pad. Not sure of the year. I have a couple 400 builder blocks, and if this 496 ever blows, guess we will build a 512. I could actually use the 496 internals, (4.25" stroke crank) and rods, put it in a 400 block and have a 512. I would only need to buy new pistons to complete the reciprocating parts. The previous builder must have had his reasons for using a 383 block. Probably all he had laying around.