The Mabaan mid engine build is nearly completed. Here is a You Tube link to a video shot yesterday. Except for a persistent over heating issue it's about ready for some track time testing.

http://www.youtube.com/watch?v=wOMzCJf1vwc

Dick Bear

That looks awesome! I want a go.

That is very cool, can't wait to see some track footage

Bet the neighbors love you!

One BIG thumbs up from me
Jacko

Very
Did it break? I looks like its bleeding on the way back into the garage?

Thanks for the comments.

@Reman, That blood is from the over heating issue I pointed out earlier. I'm working on it.

Dick
Rescued attachment IMG-117.jpg

that is awesome!

What a wonderful engine noise!

Fellow builders,

As was noticed by many of you in the latest video I am confronted with an overheating issue and am hoping that you might be able to suggest one or more solutions for correcting it. Attached is a diagram of the current system with the primary components labeled for reference.

I’m relatively sure that the size of the radiators are sufficient for the job since their combined sq. in. dimension is 20% greater than the radiator that cooled the engine originally.

To date I have:
1. Vacu-pumped the system eliminating the possibility of an air lock in the system,
2. used only water as the coolant and
3. am using a 16 lb radiator cap.

I plan to:
1. Install new debris screens having less restrictive openings and
2. add “supper cool” to the coolant.

Another suggestion that have been made but as yet not tried:
1. Install a 160 degree F thermostat.

Everything is open for discussion. If you recognize a flaw within the system or just have a gut feeling for solving the issue, I am interested in hearing about it. The only limitation is the fact that the twin radiators cannot be increased in size beyond what they are now. There simply isn’t any more room in the side pods.

Thanks in advance for your comments and suggestions for solving the Mabaan’s hot flashes!

Dick Bear
Rescued attachment Mabaan cooling system.jpg

Based on what you've done already unfortunately leaves airflow as the likely problem. Might have to do some wool-tuft testing to see what's going on.

About the only other issue it could be is that the engine was built way too tight, which seems unlikely if the guy's a pro.

Hi Dick,

Have a read of this:

http://www.gt40s.com/forum/gt40-tech-engines-induction-exhaust/13167-cooling-system-questions.html

and this..

http://www.arrowheadradiator.com/14_rules_for_improving_engine_cooling_system_capability_in_high-performance_automobiles.htm

so assuming that the piping is not too small, my suspicion is that the radiators would do better in series than in parallel as this would keep the velocity up in the system.

Awesome build.

Have you checked the water temperature differential across the radiators - if insufficient then air flow is the problem. Should be easy to do with a couple of temp sensors.

A quick note before I catch a plane in Charlotte. I'll be out-of-pocket for a few days without internet access. Great suggestions so far please continue!

Dick

I must first congradulate you on an awsome build :b

According to your diagram, the radiator on the left is the further than the one on the right. Assuming that in all pressurized systems the liquid will use the shortest route , the fluid running in the right radiator will flow in a shorter cycle and the fluid in the left radiator will flow slower as the fluids find a short route.

Another assumption is that you could be using the wrong T couplers which could be slowing down flow FROM one of the radiators back to the engine. The attached image shows two types of couplers and I'm assuming you might be using type "A". Type "B" coupler assists flow in a certain direction which might help you direct the fluids more evenly.

Other then this, Doug68's series suggestion is another good idea

[Edited on 1/7/10 by Gakes]
Rescued attachment T couplers.JPG

As already suggested, I would have just put the rads in series. Seems simplier and you ensure all the cooling water goes through the maiximum cooling area.

Cheers

Fred W B

[Edited on 1/7/10 by Fred W B]

You've probably already done it, but have you checked both radiators are getting equally hot.
Also is the radiator temperature at the inlet greater than at the outlet.
Someone on here posted that one cause of overheating at the engine is if there isnt enough water flow to the radiator(s) - you dont push the water round the engine fast enough to stop local superheating in the engine and therefore boiling.
Maximum cooling for your system will be achieved with no thermostat (maximum flow evrywhere) - does it still overheat if you run without the thermostat. If not, then you just need enough flow through the stat - remote housing or a different stat may do the job. If it still overheats with no stat in place and the radiator temperature (inlet) the same as the engine temp, you should look to increase the water flow rate (bigger pipes, change water pump pulley for a smaller one or electric water pump), or a more powerful fan to increase air flow (if you can get one).
Is the air flow restricted on the outlet side? Some ducting there may help

Regards
Hugh

Thanks to each of you on Locost Builders.UK and Locost USA.com who offered suggestions for evaluating and correcting the overheating problem on the Mabaan build.

I’m back from a long weekend trip to Iowa and ready to attack the issue armed with the suggestions made by you all. I’m sure that through one or more adjustments drawn from those offered the issue can be solved.

To help organize my plan of attack I thought I’d list the suggestions here in one place for quick review. Perhaps in the future others may run into a similar situation and find the paraphrased information/suggestions provided here helpful as well.


AIR FLOW:
KB58, carguy123, Kartracer47 and olrowdy-01 offered suggestions for analyzing and increasing the effectiveness of airflow through the ducts and radiator cores including wool-tuft studies and cautions associated with rad angle, relative intake/exit dimensions, air direction diffusers as well as concerns about the debris screens.

Olerowdy-01 listed two suggestions for information and review: http://www.ch601.org/resources/cooling_systems2.htm and viewtopic.php?f=23&t=4406&start=75

I’ll be conducting airflow circulation studies. Thanks!


ENGINE BUILD:
KB58 alerted me to the fact that if the engine is built “too tight” an overheating issue may occur.

Based upon the race engine experience of the builder I don’t see this as being a factor but thanks for the alert.


RADIATOR BLEED TUBES:
Kartracer47 pointed out the need for bleed tubes from the rads to the higher components of the cooling system to eliminate the possibility of trapped steam pockets forming in the lower areas of the rads.

Currently I have bleed vales on each rad but neither of them is connected back to the surge tank. I installed them to drain-off trapped air during the initial filling of the cooling system. An open valve connection will be one of the first retrofits made. Thanks!


INNATE CHARACTERISTIC OF LT1 ENGINES AND LEVEL INSTALLATION:
John Hennessy identified a potential problem when this engine is mounted in a level orientation (as is the case here) causing trapped air (steam) to form in the rear portion of the heads.

John’s suggestion of tapping into the rear section of the heads with a pressure release pipe or tube connected to the thermostat housing will be done. Thanks!


COOLANT FLOW:
Oldejack suggested and MYTF seconded his suggestion of running the rads in series rather than in parallel as they are now. He also suggested in-line flow restrictors to control time and velocity of the fluid as it passes different areas in the system guarding against possible unequal usage between the two rads. Doug68 provided two interesting and extensive reference sites dealing with coolant flow, rad and pipe differences and a convenient list of basic rules for reducing heat in performance engines.

http://www.gt40s.com/forum/gt40-tech-engines-induction-exhaust/13167-cooling-system-questions.html

and

http://www.arrowheadradiator.com/14_rules_for_improving_engine_cooling_system_capability_in_high-performance_automobiles.htm

Gakes pointed out possible fluid flow issues caused by different configurations of hose connectors “T-type” vs. “Y-type” connectors and seconded the series arrangement.

Fred W B agreed with series over parallel plumbing.

Hughpinder agreed with the series plumbing and suggested running W/O a thermostat in addition to suggesting the possible need for an auxiliary water pump to increase flow.

Interestingly, I debated with myself, series over parallel plumbing, and it seems that true to my history of choosing the wrong choice in a 50/50 proposition, went with parallel. Now with the preponderance of you believing that series would be better, it will be changed to series. Thanks!


CHECKS TO BE MADE:
Ivan suggested checking temp differences between the rads to determine if flow is an issue.

Thanks to all who offered system critique and possible solutions. Again, I’m confident that through one, or more likely multiple corrections, drawn from your experiences this problem will be alleviating on the Mabaan.

Thanks again,

Dick Bear

Hey all,

It's been a while since I posted, but following all the suggestions and comments regarding the overheating issue, I ripped-out everything from the side pods and redesigned the cooling system to a single, double core, double pass radiator located directly behind the cockpit and in front of the engine. This accomplished all the alternatives suggested by you in one fair swoop. Thanks!

It runs cool now!

Won't be long before the Mabaan is tested on the Virginia International Raceway (VIR) for the first time.


Description


Description


Description


Description


Description

Awesome work! Your skills are inspirational. Cant wait to see it in action

interesting build there!

for future reference, i'd say the poor cooling performance was almost certainly down to your duct design. there are plenty of texts that cover good duct design

as for the parallel or series arrangements, heat exchangers are more efficient the greater the source to sink temperature differential, so parallel should cool more effectively than series since the fluid entering is always as hot as it can be, but there are a number of other contributory factors in the design.

glad you've got it sorted with the redesign anyway

what does the car weigh, out of interest?

As always, thanks for the kind words and interest.

The Mabaan weighed wet at last check: 1,600 lb. without driver. So with my 195 lb. self buckled-in the final will be somewhere near 1,800 lb. total.

Dick Bear

With the side pods now clear of radiators maybe you could turn them into ground effect tunnels?
Of course its going to take a while for the grin to wear off from driving it just as it is I would think.

Description


Description

@Doug68.... Looking back I realized that I had never posted any images of the underside of the Mabaan. As you can see from these early fabrication photos the Mabaan already has twin ground effect tunnels built into the underside of the pods. Now that the pods are empty, I plan to split the air passing through the side pods and direct a portion of air into the front of the radiator. The remainder will exit the rear of the pods in the normal manner.

Dick Bear

Yesterday I placed the rear panel on the car for the first time since making several changes during the last 6-months to the internals correcting the over heating issues I had. I knew that taking the radiators from the pods and installing a single unit at mid-ship (between the cockpit and the engine) would require some refitting of the panel so my day was spend evaluating what needed to be done and I slowly began to make those adjustments.

It's not completely corrected at this point but I have confidence that with a bit more tweaking the large rear panel will once again slide into place as it had done before. The major change needed will be to form twin blisters to accommodate the upper-outside corners of the radiator (see red circle).

I'm still waiting on the NCDMV to return the documentation for registration, title and licensing. Hopefully that will arrive by the end of this week and we will add a new member of the 'street legal' club. I won't celebrate until the Custom 2011 classification VIN number is placed onto the Mabaan's frame by the Inspector. At that time... I surly will!

Dick Bear


Description


Description


Description

[Edited on 2/21/1111 by Dick Bear]

[Edited on 2/21/1111 by Dick Bear]

[Edited on 2/21/1111 by Dick Bear]

I received a call from NCDMV Inspector R. this afternoon wanting to set-up a time on Friday to attach the 'Custom Built 2011 VIN' to the Mabaan.

Next stop ... file for a title, pay registration fee, notify insurance company and hit the highways and byways!!!!!!!

It's been a long time coming but worth it!

Dick

You can checkout the sound and a brief drive of the Mabaan on the street at:

http://www.youtube.com/watch?v=-nKWSswGIoM

Dick Bear