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The BORA

Discussion in 'Maserati' started by wbaeumer, Aug 11, 2011.

  1. boralogist

    boralogist Formula Junior

    Jun 21, 2005
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    #451 boralogist, Nov 17, 2018
    Last edited: Nov 17, 2018
    Hi Ivan..

    Please note that I referred to the thermoswitch on the radiator which activates the fans.
    Talk to Stuart at MIE for the lowest temp thermostat and matching thermoswitch he has (or, at least, had).
    Regards. B.
     
  2. staatsof

    staatsof Five Time F1 World Champ
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    No.

    I wish I had a fool proof and complete solution to suggest but honestly I do not and beleive me I have tried. My friend and I had identically setup Boras both with upgraded radiators too. He'd done a number modifications to prevent water pump cavitation which he felt was partly the cause of his puking coolant at times. Stock, the pump's impeller is a straight vane design which is more efficient at low rpms but also tends to cavitate at higher rpms. He elected to install the impeller from Mercedes 6.9 water pump which has curved vanes.

    His family's business has been water pumps and aircraft propellers going all the way back to the 1920's. The Jacuzzi family. He had no hood vents and I did. Mine ran hotter but it's more complicated than hood vents. I went to the trouble of changing the air exit path to match his identically albeit on a temporary basis. It did not run cooler. I also installed the water pump mod and it didn't help but I did notice the lower flow at low rpms. Mine had the heads rebuilt and everything looked at in the cooling passages. I even ran mine for a while with pure water and water wetter. The water wetter did nothing. Getting the car's cooling system bled free of air is obviously very important. Putting the back of the car up in the air helps with that. I know I accomplished that much and one way to help is to attach a tee fitting on the top of radiator fitting that goes up and over the roof right at the radiator. I have a 1.5 ft length of hose with a brass fish tank valve on it and whenever I'm bleeding the system I open that valve and submerse it in a clear jug of coolant mix until the bubbles stop. Then I stick the hose and valve back inside of body housing till the next time. It's also a very easy way to see if air has gotten trapped from time to time.

    I eventually came to the conclusion that some motors just run hotter. But the system in general is under capacity so a 2" think core with 11 fins per inch seems to be about optimum.
    You also probably aren't going to drive yours like I did mine. So I do think you can improve your situation. I was interested in adequate cooling at 100F and 140MPH for extended drives. I never quite got there but I got things better.

    I never tried an aluminum radiator but others have. I did a ton of hot weather testing with all of these mods as in the desert in Nevada. I even fabricated extraction scoops for the vents in my hood/bonnet. They were adjustable in rake too. It didn't help ... :(

    Now I'll get to what I believe is the basic problem with these cars when pushed hard or driven for extensive periods in hot weather. Before I do I'll just say this. Drive them in the spring, fall and winter and you'll not have such issues! :)

    So my one friend who used to have a Bora with all the modifications, it's the black one you see in the MIE ads for Emil's service, went to the Nevada open road race known as The Silver State with another friend of his, myself and another friend of mine who brought his Bora to the race. That car had most of the cooling modifications and was 1977 my. AFAIK that's the only Bora to ever enter that race. I was the codriver/navigator in the Bora though I'm credited as the driver in the video that's out there on the internet. My other friend had brought his Mercedes 6.9 to run in the race.

    The day before the race I drove that Bora on the race course backwards hitting speeds of around 160 mph, it had the European final drive ratio. We had no cooling issues on that run of any significance. But on race day it was a very different story. Most unfortunately someone went off early in the morning in a Testarosa, crumpled it up into a ball about the size of a card table killing his wife in the process. It was very hot before we got started again so this time the car got a real test. We ended up having to limit top speed to 130mph which made for an embarrassing overtaking by a Ford Taurus SHO! :eek:

    What was revelatory though was when I suggested we crack open the windows and put the heater on to gain extra cooling. As soon as we cracked open those windows the cabin filled with dark smoke! The reasons for why really gave us an understanding for why these cars have a cooling issue. Once we finished we opened up the hatch, took off the cover and discovery an oily mess. It seems that a bolt which holds the idler tension on the AC compressor is tapped through to the crankcase on his car. It had fallen out and so oil was coming out, burning on the headers and then the smoke was going forward into the cabin via that central fiberglass tunnel. This at 130 mph! When we reviewed the event video we could see that when we passed the high speed camera point the rear body was a full 2" higher from the tops of the tires to the highest arch point of the wheel well than when parked.

    That means that there's a ton of high pressure under the car and it stalls in the engine compartment thus pushing that smoke forwards. This car also had the Merak style spoiler lip installed.

    I wish I thought there was a real solution for this WO modifying the car unacceptably but I do not.

    Now theses are extreme conditions to be sure but it highlights what I think is a fundamental design flaw which eventually shows up at even more reasonable driving speeds in hot weather. Airflow in the engine compartment is terrible and that leads to heat soak of that entire massive metal structure back there, a condition which just completely overwhelms the rather puny cooling system. I've experienced this heat soak issue many times while traveling at normal speed in the summer. I just pull over in the shade for an hour and let it dissipate. If you look at more modern mid engine cars they all have designs to facilitate good airflow out the back. Ferrari has utilized black grill work on the rears. Others also have side vents for both radiators in the rear as well as inlets for engine combustion intake and general cooling of the engine compartment. The Bora operates with a cover in place and that is under glass! :eek: Very pretty to look at but in hot weather it's a disaster of a design once you start driving hard or for long periods of time.

    I also had some woven high temp glass fabric which I got from one of NASA's suppliers wrapped around my headers and that didn't fix it either.

    Leaving the carpeted cover off only gets your car dirtier faster. The theoretical venting design is supposed to be dependent it's being in place.

    If you look at a Pantera's or GT40's radiator placement and hood vent layout that's probably what would divert much more air up and over the the windshield this reducing the lift in front and rear but that completely changes the look and practicality of the Bora as it eliminates what is a really functional luggage compartment.


    You've gotten some good tips from others here so try and upgrade your radiator and fans as that should help but don't be surprised if you never quite get it perfect. Radiator fans are only helpful at slower speeds. I also have switches to turn the fans on manually. One of the first things I did. Clearly these cars produce and retain far too much heat to be shed by a cooling system of this design. I firmly beleive that some engines just run hotter than others. I wish I knew why when they're identically set up?
     
  3. Froggie

    Froggie Karting

    Sep 27, 2017
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    Thank you for this very interesting reporting and analysis.
    Do you know if/how the Gr.4 Bora's circumvented the problem?
     
  4. 71Satisfaction

    71Satisfaction Formula Junior

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    #454 71Satisfaction, Nov 18, 2018
    Last edited: Nov 18, 2018
    Mine had persistent overheating problems going back to prior owners, gushing coolant out the pressure overflow hose. Without making assumptions about yours, I'll just share what finally solved my Bora's overheating problems.... (1975, US spec 4.9L)

    We did the following and it finally stopped overheating:
    - Removed the A/C evaporator and adapter plates from the front of the original radiator.
    - Removed and cleared the bleeder nipple at the thermostat housing.
    - I added WaterWetter to the coolant and I measured I got the entire 2-1/2 gallon capacity in (no air-locked voids).

    My Bora has not overheated since. It passed its biggest test when inching along in an August traffic jam with 95F outside air temp without overheating.
    - Normal coolant temperature is 80-85C in most "normal" driving regimens.
    - It'll max out around 95-100C in hot or repeated high-demand conditions.
    - It'll drop to 75C at speeds above 120mph.

    Prior to the above we had already: Flushed the radiator and engine. Verified the engine t'stat and radiator thermal fan switches operated to spec. Checked the water pump, and ensured the A-pillar air tube to the header tank was clear. Removed and flushed the main steel coolant tubes in the tunnel with an abrasive slurry to remove any scale rust.

    I'll add a plug for the excellent service I and my Bora have received at Dave Burnham Citroen's shop. Outstanding.

    Best wishes,
    - Art

    [Post Script Edit: I also found the carbs were adjusted a little lean. I now run a correct mixture, but it must be a tad rich because there is usually a thin layer of carbon on my rear bumper.]
     
  5. am117au

    am117au Karting

    Apr 22, 2014
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    Greg G
    Well i asked the question and certainly got more than i bargained for. The quality of the response is outstanding for which i am grateful.I just wish i was more proactive and sought the counselling from my fellow Bora owners prior to me finishing the assembly
    This now leaves me with the dilemma of which way to attack this problem.
    I can say for sure i won't be visiting the Nevada desert any time soon but i do want a car which is reliable and will handle everyday driving with temperature in the mid 90's.
    I will get a new radiator fabricated as well as a new shroud to accommodate the largest fans possible.. Research indicate that Spal is the way to go as Boralogist suggested. Furthermore i will discuss with my auto electrician of installing an override switch for the fans for a manual operation or sync them to come on together when the a/c is switched on or the temperature is reached.
    I will post my outcome later.
    Greg
     
  6. staatsof

    staatsof Five Time F1 World Champ
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    Sounds reasonable Greg. Another mod my friend made with his Bora was to improve the airflow of the interior AC fan's circulation. I never did this one but he swears by it. Basically what he and his son found out one day was that intake (re-circulation) opening for the system was grossly undersized and acted like a choke. They discovered this quite by accident one day while they had it running and he asked his son to crawl in the trunk and remove a panel in the front trunk but could not. When they turned the fan off it came right out. They were in the process of upgrading the blower fan. He also added another quasi discrete outlet in the dash but I doubt you'd want to do that one. His AC always worked on hot days in the eastern SF bay area so mid to high 90F. He didn't take his car on long excursions into the desert. Mostly he drove to Monterey and back with one trip to Lake Tahoe which is pretty substantial.

    BTW here's the link for 89 Silver State drive. I'm in the green shirt.

    The quality is terrible of course and was better on VHS at the time. Gosh 30 years ... gulp!

    The radiator is a PITA to remove because of that finger slicing mesh but a two inch core fits just fine. Maybe a completely new one in aluminum and have it black anodized? ;)
    My very first repair on my Bora within one hour of purchase was to replace on of those fans. It had melted because it was on but stuck. Fortunately it was a common fan used on a Mercedes and fortunately there was a dealer nearby who had one in stock. I gushed water about 10 blocks from where I bought it. I went right back and we had it sorted in about 1.5 hours.
     
  7. staatsof

    staatsof Five Time F1 World Champ
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    Well they have an entirely different rear hatch with more venting and air scoops in the corners which tried for engine intake only. I don't know how that all worked out. They never raced back in the day but one of them was arced in Vintage during the late 1990s. Marc Sconnery knows more about them. He's on here regularly. Perhaps he'll chime in?

    I used to run mine at the track for 30 minute sessions WO overheating terribly but the hatch was opened up in between sessions. We even had a pair of them running at the same time. Some fun times.
     
  8. emsiegel13

    emsiegel13 Formula Junior

    Oct 9, 2007
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    What I find interesting is the muffler arrangement in the Bora. In the US models, the location of the muffler seems to negate air extraction by blocking the lower area of the rear end that has a mesh panel. Why have that mesh panel if you end up blocking it with the muffler? Even in the European version there is the blockage of air out of the engine compartment by the location of the muffler. I wonder if another arrangement of the exhaust system that would permit more air to exit the engine compartment would, in any way, improve the heating problems.
     
  9. staatsof

    staatsof Five Time F1 World Champ
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    OK but cool air needs to get into the intake system as well as the engine compartment so as to extract heat. What's coming underneath has already been heated by the radiator.
    Just letting that air escape out the lower back still isn't helping in the cooling effort.

    Not good.
     
  10. emsiegel13

    emsiegel13 Formula Junior

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    I thought that the heat from the radiator, on the US cars with a trunk lid vent, is supposed to go out on top of the car. Granted the water pipes are in an open trough underneath the passenger's compartment and exit into the engine compartment with an opening underneath where they turn up but I assume that the exhaust pipes add a bit of heat to the engine compartment also which would effect the engine block temperature. Everything I have read says that keeping heat in the exhaust pipes serves at least two benefits, greater velocity for scavenging from the cylinders and keeping heat out of the engine compartment in general which effects engine operating temperature and incoming air temperature for the engine. It certainly doesn't help the Bora that there is no outside fresh air pickup for the carburetors. Also, increasing the efficiency of air extraction from the engine compartment seems to be a major point for most high performance automobiles. I just wonder why they do so much work in that area? I suppose that every little bit helps to make for a more efficient package.
     
  11. staatsof

    staatsof Five Time F1 World Champ
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    What the Bora needed was development time in a wind tunnel. Look at that video and notice all the lift under the car. But hey ... cars weren't developed for aerodynamics as much back then. There's nothing aerodynamic about a Countach. The Bora did have a very low cd but that's not the entire goal. At speeds like 160 mph it was quite the wanderer. When I drove that course in 1990 I did it in new Infiniti Q45. That car had an even lower CD and was rock stable at those speeds.

    Any way, at this point in time no one is trying to use these cars for events like that or even drive them that fast. Today they're beautiful cars and quite nice drivers for that sort of car from that era. The best of the bunch for carrying people and luggage. Modifying the car's looks in search of better cooling and or stability at high speed doesn't make a lot of sense to me now. I doubt you're going to enhance a car's appeal by turning it into a Group 4 Thepenier Bora. There have been some attempts over the years though.
     
  12. Nembo1777

    Nembo1777 F1 Rookie

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    #462 Nembo1777, Nov 20, 2018
    Last edited: Nov 20, 2018
    Hi Bob,

    Who is Sconnery?;-)

    Yes I will chime in but am headed to Sicily to inspect a Lancia so it will be in a few days.

    Here a photo of the second Gr4 #3001 which has seen far less action than #3000 and is more advanced and as it was when it left the factory.

    This is a photo from my July 1995 test drive and photo shoot at the Jean Pierre Beltoise safety course track in Trappes near Paris, though it was much more of a photoshoot and just a brief drive. I drove #3000 properly June 22, 2009 at Paul Ricard.

    Amazingly and sadly #3001 has not been out in the sun once since that day 23 years ago...

    This photo shows how the rear plexiglas is fully vented and by the way it weighs faaar less.

    Another point that should be discussed when improving cooling is deleting the inner wheel arches. In other cars that made a huge difference.

    Photo strict copyright.

    Best regards,

    Marc

    Image Unavailable, Please Login
     
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  13. staatsof

    staatsof Five Time F1 World Champ
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    He's an amiable typo fellow ... :p

    I think the hatch is still steel though or is it aluminum? Fiberglass might have been nice ... Stock that hatch is really GD heavy.

    Just imagine if the factory had come out with a street version that looked more like that with about 450 hp! BBLMs would have gone into hiding.
     
  14. emsiegel13

    emsiegel13 Formula Junior

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    If I remember in the years of the Ferrari-Maserati Challenge, the one GR4 Bora did very well against the competing Ferraris of the same generation. Sadly, I don't recalling recent activity by the GR4. Perhaps someone else knows more about anything that has occurred recently with the GR4. If so, I would certainly like to hear more about it.

    Marc, when you have a bit of time, within your range of knowledge, could you give some engineering background on the two GR4 cars as opposed to the history which you have so adequately covered in your book. Anything about the engineering and mechanics, such as any modifications to structure, materials, suspension, engine internals, etc. would be most appreciated. I wonder if there is still anyone around who was involved in creating the two cars that could pass on information to the group.
     
  15. Froggie

    Froggie Karting

    Sep 27, 2017
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    Many of us here support that idea!
    The issue at stake is probably ... a bit of time;)
     
  16. staatsof

    staatsof Five Time F1 World Champ
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    These efforts at figuring out what was done for the Thepenier Boras remind me a bit of like trying to fight the battle of Waterloo all over again.

    If you're that enamored of what those cars "achieved" ????? Then buy one and leave the rest of the gorgeous Boras unmolested ... save for the obvious and hidden improvements.
     
  17. 71Satisfaction

    71Satisfaction Formula Junior

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  18. boralogist

    boralogist Formula Junior

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  19. staatsof

    staatsof Five Time F1 World Champ
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    If you have the original VCR tape and I do ... it's a much better video than this Youtube piece and not hard at all.
    The high pressure was very real. How else would you explain all that smoke filling the cabin @ 160 mph?
     
  20. boralogist

    boralogist Formula Junior

    Jun 21, 2005
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    With due respect to all, there is nothing to suggest there was any 'high pressure' documented in those stills at all.
    Another fantasy ( or fake news in today's parlance) bites the dust!

    As to the cabin smoke there are a variety of unrelated, plausible scenarios.
    My first suspect would be the gear shift lever leather surround---I always had problems with gushing hot air from there at speed,
    until I sealed it off.

    Finally---I was too busy making money thirty years ago to play with my Bora (acquired 9/87) as much as I do now!
    Therefore I can only speak to the present.
    Yes, the Bora is squirrely at very high speed; yes it writhes around its steering wheel like earlier 911s; yes it is hyper sensitive to road
    irregularities and yes I always turn the EZ PS off over 100 mph or so.
    BUT i have seen 6000 rpm many times (actual 168 mph) and will do so again!
    Q.E.D.

    Regards.
     
  21. staatsof

    staatsof Five Time F1 World Champ
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    LOL! You obviously mean quite the opposite.

    But let's look at the conditions of that event and my experience with it.

    I've officially run that race twice and attempted to enter another two times. Which means I spent a lot of time driving my Bora, another friend's and one other car at those high speeds. Check out the route from Fallon to Ely Nevada which is how you get there when coming from San Francisco. On that part of this event is one of the loveliest high speed roads in the USA, all 250 glorious miles of it on highway 50, "Loneliest Road In America". Watch out for errant cows and very hard to see road resurfacing bumps.

    https://unusualplaces.org/u-s-route-50-americas-loneliest-road/

    [​IMG]

    [​IMG]

    Then there's 90 miles from just outside of Ely @ Lund down to the race's end in Hiko/Crystal Springs. From there entrants drive to Las Vegas, another 109 miles. Most of us were driving pretty damn fast on that road as well. That's 502 miles of high speed driving. Then there's the return trip ... on highway 50 at least you can pretty much go as fast as you like. The other roads resume to normal speed list after the race is over. I've done the full race twice, once in that Bora and once in my 90 Q45. I've driven the entire course and back two more times in my own Bora. I think that 4,000 miles at speed alone more than qualifies me as knowing how this car performs under such conditions.
    I have plenty of other experience with the car at much more normal conditions.

    Do you have something equivalent in your experience with the Bora?

    Did you do all of the experiments that I and others have working to make it perform better under such conditions?

    I have already relayed the story of why the cabin filled with black oily smoke from the rear a couple of times on Fchat. Try Search.
    The seal between the center console and the floor of vehicle is haphazard at best. The ash tray, parking brake and shift boot are hardly hermetically sealed. Pull that leather center console out and it's a straight, wide open shot into the engine compartment along that shift linkage. It's no wonder why fumes can get in from there especially when there's a high pressure condition in the engine compartment which is where the oil was leaking and burning. Nothing in the front can burn oil like that and if the air flow in the engine compartment was functioning properly that smoke never could have entered the cabin. That's the entire point!

    If you don't want beleive the facts in evidence then I certainly can't compel you to do so. But ... those are the facts and while you're certainly entitled to your own opinions you are not entitled to your own set of facts.


    Q.E.D? Oh please ... the only thing you've demonstrated, once again ... I thought you had settled down :rolleyes: , is that you don't like what I'm saying and resort to potshot attacks on my evidence and conclusions then exclaim that you've run your car up to redline many times and will do so again and that you've been very busy making lots of money? WTH is that all about? Bully for you but what does that have to do with this topic?

    I already stated that I agree that the Youtube video is of such low quality that seeing the lift in the rear is not possible. Try and find a good copy of the event. VHS tapes do show up on eBay from time to time. When my other friend with the Bora got home after that race in 1989 he ordered a VHS of the event once it was available. That's when he called me all excited with this new piece of evidence. He's a very well know long time Bora owner. Ask FGM about George Marin or ask Eugene O'Gorman.


     
  22. boralogist

    boralogist Formula Junior

    Jun 21, 2005
    304
    Enjoy your memories from 30 years ago old timer!
    Some of us are actually creating new ones day by day!

    Regards.

    Over and out.
     
  23. staatsof

    staatsof Five Time F1 World Champ
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    I figured as much.
     
  24. 71Satisfaction

    71Satisfaction Formula Junior

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    Mine does this too, and I attribute it to front end lift.. Your choice of words about "fantasy" and "fake news" reads as if you think Bob didn't experience lift? Even though you can't *see* or reliably measure lift from the video or stills, doesn't mean it's not there, hence my note on the video that Bob more likely felt it in the steering. I haven't had mine over 140 and hasn't quite gotten to where the lift causes it to "writhe" or be "hyper-sensitive", but I can imagine it would. Air pressures around a high-speed car are complex.

    Maybe I'm misinterpreting your comment but when you say that "fantasy" and "fake news" about Bob's experience with lift, and then follow it up describing your own Bora experiencing lift, it makes you sound very conflicted.

    I also have hot air coming up the shift lever boot (and front footwell) and the cause is pretty much as you both describe - there are gaps all up and down that tunnel and leather cover. Be that as it may, I've not experienced that air as smelling as if it originated in the rear/engine bay and migrated forward.

    Air currents in and around a car are extremely hard to determine without video cameras and tufts of wool..
    Cheers,
    - Art
     
  25. boralogist

    boralogist Formula Junior

    Jun 21, 2005
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    [QUOTE="71Satisfaction,

    Maybe I'm misinterpreting your comment .........................................but when you say that "fantasy" and "fake news" about Bob's experience with lift, and then follow it up describing your own Bora experiencing lift, it makes you sound very conflicted.
    Cheers,
    - Art[/QUOTE]

    Hello---

    Yes , you are!

    My problem with 'fake news' is with self appointed experts, constantly repeating their highly subjective brief experiences with a particular car,
    from many decades ago, as gospel.
    That the Bora may experience some front end lift is entirely true.

    That is why I installed a Merak front spoiler a few years back.
    It has been very effective in reducing the 'wandering' sensation I always felt at speed.

    I never suggested that the Bora being squirrely at very high speed, writhing around its steering wheel and being hyper-sensitive to road
    irregularities was due to front end lift.
    There are many highly complex issues at work here, beyond the scope of this brief note.

    Thanks.
     

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