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Discussion in 'Maserati' started by wbaeumer, Aug 11, 2011.
Have the heads been re-torqued after the engine was rebuilt?
Its strange that you ask if the heads have been re torqued as i spoke to the engine builder about a week ago about this and i am taking it in to him mid to late May.
What i would love is if someone could explain why air in the cooling system would cause the engine to overheat as this is something i intend discussing with the engine builder.and i need to be armed with answers so i don't get fobbed of not that i expect he will do that.
Greg what do you mean by air in the engine? Is just air or are you getting exhaust gasses in the cooling system? That was just discussed earlier in the thread.
These cars are a bit tricky to fully bleed of "air" even with a healthy engine. The later ones came with an air bled valve on the rear of the RH head to assist with this. That's a bit messy. You should be bleeding the air when you fill the system with coolant via that vale with the rear of the car jacked up from the ground. The bleed line from the top of the radiator that goes over the roof on the inside can be a problem too as you can't get the rear high enough to make certain the air that collects at the top of the radiator gets fully expunged through that line to the tank in the rear. To assist with this I installed a tap at the corner connection point there on the top of the radiator with a length of hose that terminates with a brass (fish tank) valve, if you can still find them? The hose is long enough so that I can pull it out from the front of the car and immerse the valve in a container of coolant. I can then open it and let it bleed out the air with the engine running. This way you can also easily periodically check for any air that's trapped there.
Air or gas trapped in the cooling system will get emulsified by the very efficient straight vanned water pump. That inherently makes for a cooling mixture which is far less effective in dispersing heat from the engine into the coolant and back out of the coolant into the air via the radiator.
You should first make certain that the car is bled properly.
Again thanking for replying to my post with constructive comments.
I took the car out today for a short drive ambient temperature approx 80 deg F with the air conditioning on and the temperature reading slowly reached 90 deg c..
I fear if i was stuck in traffic it would easily gone to 95 to 100 deg C suggesting i have not solved the over heating problem.
Air/ gasses in the cooling system is definitely the next item i will be addressing before i attempt anything further.remedies hoping that this will be the cure.
Armed with the suggestions on filling and bleeding the system i should definitely be able to eliminate if this as the problem.
Will keep you posted.
In case you missed it, I wrote to the forum the following, in November 2018:
This is a very complicated issue and there is no magic bullet!
First of all please note that your overheating issues HAVE NOTHING TO DO WITH HAVING AN EARLY CAR WITHOUT THOSE HIDEOUS VENTS ON THE HOOD.
Nonetheless, you have to start somewhere:
Step 1. Junk your original radiator and have a custom (min 500 bhp capacity) racing radiator built to its exact dimensions.
(Mine was built by Evans ---of coolant fame--- in the US)
Step 2. Have a custom shroud manufactured to house your two new monster Spal fans.
Step 3 Purchase 2 new monster Spal fans.
Step 4. Install 70 deg. C thermoswitch.
Step 5, Make sure system is rewired so that both Spals kick in simultaneously.
Step 6. Fill system with 70% distilled water and 30% antifreeze.
Step 7. Add two bottles of Redline WaterWetter.
Step 8. Discard your alternator and replace it with a Bosch unit in excess of 100 amps---necessary to feed your new Spals.
MAKE SURE YOU PUT AWAY YOUR ENGINE COVER FOR GOOD!
Come back and report.
Please note that these measures are not negotiable and that we can not proceed to the next steps (if necessary) until each item listed above has been
Have you done ALL of the above???
If you have, I will be happy to guide you further, as I originally wrote in italics, above.
In my humble opinion, if you have driven your Bora 50 or so miles and then topped up your coolant tank, you are DONE with that topic.
Interesting solutions. Individual results will apparently vary.
My '75 with hood vents overheated persistently under several prior owners. Now it doesn't. I'm using the original radiator, original alternator, original thermo switches and original radiator fans.
I posted what we did earlier in this thread, but in summary: We checked all bleed valves worked correctly, we bled it normally without jacking it up (and it took the specified amount of coolant 2.5US gallons), we removed the AC condenser including adapter plates, and added Water Wetter. That was it. Done and done.
Best of luck,
Are you sure the water temperature gauge in your Bora is 100% accurate? It might just be reading a bit high. If you have not done so, read the temperature with an infrared thermometer pointed at the hose that goes to the thermostat in front of the engine .... and compare to the car's gauge.
He's got some things in that list that really will help Art. If you're sort of doing OK now with the original radiator then you could do even better with an upgraded one. You might want to measure the core of your radiator and check the fins per inch count. It's possible a PO has already done that. I had all the original end hardware moved from my original radiator over to the new one so it just looks thicker but still very original. Better fans are a good idea too but if you have heating issues at speed on a hot day like I did fans aren't going to do diddly for that but at lower speeds like when you get stuck in slow traffic after driving at speed and using that power. That's what some of the original approaches to this problem were about. My Espada did the same (now) idiotic thing by adding in the second fan after a certain temp and the fans are pushers with no shroud at all! But with a relatively weak alternator this was one way to reduce the load on everything. Italian cars were always poorly designed from an electrical standpoint. Even my 84 Biturbo had alternator issues. It now has a much better Delco 100 amp unit in it. I had my Bora's alternator reworked to increase the output soon after I bought it too.
Fan failure was the first thing that happened when I bought my Bora in Oklahoma City. It was a warm day, high 80sF, in early spring and lest than 5 minutes from leaving it blew it's coolant. We drove back and there the seller's agent and I dove into the problem to find a seized fan motor which then got so hot it melted the fan blade and was ruined. I suspect is was the museum time that caused this and later other issues. We quickly figured out that these were also used on a Mercedes so up the street to the dealer there we found one. Two hours later we were back on the road.
If you don't have any very basic other issues as I asked Greg about then these will get changes most people to a point where they can use the car reasonably. I never had any luck with Water Wetter in any of my cars but lower percentage of coolant does help make the system more efficient. There are other additives you can use to compensate for the ones missing. But not for winter freezing protection!
None of this solves the bigger issue of engine compartment airflow which is what makes it a problem for sustained high speed travel when it's hot or the issue of heat soaking when you stop for lunch on a hot day. Not an issue in winter, later fall and early spring weather when the engine loves all that cool air.
BTW, a while back I mentioned the idea of finding software that would allow one to simulate air flow tests. based on a computer model of our cars. I asked on here in one of the subscribed sections I think (?) and I got a very good response. Yes there are ways to do that now which some enterprising real engineer could use on these cars to help out. If someone is interested I'll go find it and see if I can move the information here. That's still not a simple task but at least you don't have to try and rent the NASA Ames wind tunnel! LOL
Thanks Bob, I'm doing much better than kinda OK - we crawled along for 30 minutes in mid-August traffic on I-90 westbound up that hill to the I-84 exit and didn't overheat. If it was going to, that would have been the time. Maybe my stubborn belaboring of the original cooling system's adequacy is more about my faith in the accuracy of Giuseppe's engineering.
However - as I allude above - I do think individual Bora's behave differently. I'm not being glib. Some vent up, some vent down. Some have finned coolant pipes, some don't. Some have scoops underneath, some don't. AC evaporators are mounted differently, or not at all. Different front bumper designs probably create different airflow too... The possible combinations are many, so results will vary.
Meanwhile - I've had the recent pleasure of encountering an extremely nice, original early Merak up close and personal. I inspected the front grille, radiator, fans, sheetmetal. The upward venting plenum looked more constricted than mine. I was also intrigued to find an air scoop underneath the front - very much like our Australian friend Greg G's scoop, centered. It is integral to the surrounding sheetmetal and faces forward. This Merak has an upward venting radiator, still has its AC evaporator mounted in front of the radiator with open side brackets, and the air scoop serves an oil cooler installed such that air vents up into the plenum behind the radiator. The oil cooler is standard for all of Maserati V6's... Now then, what purpose the scoop was intended to serve on the Greg's Bora is perhaps something to ponder -the scoop's intended orientation may very well have been facing forward. Why? Perhaps to channel air down along the steel coolant pipes? It's not clear.
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I'll have to try and take some photos of mine next time I'm out at my remote garage. The finned coolant pipes was an Idea from Ted Bonney, gone now, who ran his Bora in Baja Mexico where he had a fishing resort. I think some others may have copied that. I ran mine with from bumper removed, I have a top vent car but it also exits out the bottom ... what an airflow jumble ... One hot day my friend who also had a Bora decided to experiment and block off my top vents just like his earlier car. No improvement and no real change either! But I suspect that in very slow traffic (creeping along) it probably does allow for easier escape of hot air from the radiator. Mine is OK but I never got it as good as I would have lied, being able to run in the hot desert WO worrying. My trip to Bull Head City was a very nervous affair. I never boiled over but the gauge always got too hot. I do think my engine just runs hotter than my friend's did and the two cars were identically set up other than the vents in the hood.
As I mentioned before these cars tend to get air stuck up underneath behind in the engine compartment and at high speed the effects become pronounced. My other friends Bora that's in that Silver State Race had the Merak spoiler lip on and I guess the steering wasn't so bad you count't drive it at top speed but it also was locked down like modern cars designed to go that fast are. My own was rev limited to 140mph because of the USA gearing and it was something of a dancer at those speeds. I never had the lip on my car.
But if yours is doing well don't look a gift horse in the mouth on this fine Kentucky Derby Day.
Sorry no photos but I had a look yesterday at the underneath of the front of my Bora. No scoop up front at all, just the openings in the front chin as seen in the above Merak. I think that scoop[ on the Merak is for the oil cooler no? The air is designed to exit mainly out the top on mine after it hits a nearly vertical wall ... But it also escapes out the bottom and there are a series of exit louvers on each side of the cooling pipes channel in the belly pan for a ways(maybe a foot?) towards the rear.
To add elements to the possible interest of /scoops and cooling issues, I noticed that my Indy when purchased was equipped with two "additional" front air scoops under the air openings in the body to cool the rad(s).
They are partly visible in this pic before restoration of the car:
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On this other pic during restoration, two successive cooling openings underneath can be seen, maybe useful to cool both the A/C rad in front and the main water cooling rad behind:
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No idea whether these scoops were useful, but probably they were put by a previous owner to help cooling, not to lock down the front at speed, as the front engine Indy is not as prone to light steering at speed as the Bora.
Turns out, when being tested during restoration, that the car was subject to overheating (cooling circuit not efficient enough) and that the cooling rad had to be recored, maybe an issue that was overlooked at the time...
My Bora is number 1000 and it has the two additional cooling openings in the front, similar to the ones show on the Indy. I suspect that the later Bora cars had this modification, maybe due to the addition of pollution controls such as air injection which raised the temperature in the exhaust manifolds which could also cause the engine to run hotter. I can remember seeing my exhaust headers one night glowing cherry red which also cause the welds on the exhaust manifold to fail, requiring re-welding. That was a nightmare.
I can't imagine any of the the Boras with the air injection remaining with it functioning for very long.
Mine had 3,000 miles on it and the PO had already removed the NUCLEAR REACTORS , had them welded back together and then tried some new idea of a thermal wrapping around them. I knew not very much about all of this at the time I picked the car up but already had about a year and half experience with my 84 Biturbo which along with the QPIIIs was another model where Maserati fully demonstrated it's utter lack of knowledge in how to built an emission system for an automobile.
To be fair ... they were trying to build a system that would deal with carburetors which had manual chokes on them. Both Biturbos and and QPIIIs were set on fire by customers who left the choke on too long ... I used to see them sitting on the roof top floor of the British Motors dealer, the west coast distributor of Maserati back at that time. The service managers would all tell me about the various horror stories LOL! One of them was a gorgeous black QPIII which had enough of an engine fire that it damaged the interior somewhat but not enough to total the car. So they ordered something like 50 sqft of that lovely butterscotch leather. Modena sent 50 pieces of leather one foot by one foot. I kid you not ...
I had removed the emission system on my 84 Biturbo after about a year and everything awful ceased happening on that car after that. But the dealers couldn't do that. Any "solutionsd" meant a complete re-certification of the car. Maserati could never afford to do that.
But I needed to register the Bora in California so I left the system intact for the long ride home from Oklahoma City. Well I tried to anyway ...
But even with no air injection and a set of proper headers on, that car will still glow the headers cherry red when you drive it flat out for any period of time. They don't crack, but things in the engine compartment get very warm, too damn hot actually. It's why I added all the doubled walled SS heat shielding. For my Ely open road racing runs I wrapped the headers in ceramic cloth heat shielding I got from one of the NASA suppliers located in Sunnyvale. I wrapped SS wire around it to secure the cloth in place. That blocked the radiant heat.
Has anybody focused on the Boomerang's engine cooling solutions?
Remarkably advanced for the time---
What would be the logic of not applying this to the production Bora?
stop video at 3:20
My Bora #932 and other Boras I've seen have the same "extra" openings, like Elliot's. I assume it was done at the factory. Maybe was got them to compensate for the giant rubber front bumpers blocking the radiator?
Regarding the Boomerang - very nice video. Nothing in front reveals how the radiator was vented, so maybe rear ir side mounted radiators? Equally hard to know whether the rear deck extractor slots and side vents acted in concert to flow air through the engine bay... Even though they look functional, with all those angles and emphasis on design over engineering, it's hard to imagine it was tuned for effect in a windtunnel or an engineering setting.
Fun stuff though.
The Boomerang was like an oven inside at Monterey when I saw it but that's not the engine compartment ... It was a spectacular looking show car after all.
Reminds me of that line from Gumball Rally. “Either the engine gets hot or we Do!
You hardy notice the glass roof panel from the camera angle used in the video... and oven for sure. The sound of the door shutting is classic Bora..
Greg - it's getting close to late May.. any visit to your engine rebuilder yet?
Reading through some of Greg's past posts about overheating.. and I caught this comment about air (bubbles?) in the coolant.. Bubbles in the coolant are a possible symptom of a head gasket problem: High pressure of the cylinder chamber forces (combusted?) air past the gasket into the adjacent low-pressure coolant passages.
I don't know whether air in coolant causes overheating, per se. It could be the heat accompanying the combusted air increases coolant temperature. It could be that air in the coolant reduces its efficacy. I'll ask around.
Not to be alarmist. The mention of retorque-ing the heads is reasonable in a freshly rebuilt engine.. Fingers crossed the solution is easy.
Sorry i haven't been active of late but i have been busy with a few other matters that need attention.
I think i am busier in retirement than when i worked.
I still haven't had the opportunity to take the Bora to the engine builder mainly because of my time restraints and he is so busy that he doesn't have room to accommodate the car for a lengthy period.We are trying to work out when it is best to get it to him. .
I will be leaving for Europe on the 12th June and i cant see that i will get the car to him prior to my departure.
I am refraining from driving the car until i get it to him as i am having concerns that it could actually be the head gaskets. Whether it just needs re torquing or something more sinister only time will tell.
A gentleman who just performed a complete engine rebuild and got paid for it, does not have the time to run diagnostics on his work and possibly re torque the heads...
Simply extraordinary where I come from!
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