I didn't get to do anything fun yesterday evening or today. When I pulled the exhaust manifolds some of the studs had 4 or 5 washers stacked together - it looked like the threads were boogered up and the spaced washers were there to keep the nuts on the good threads. I wasn't going to put it back together like that, so I put double nuts on the first stud and it unscrewed pretty easy. The second stud came out even easier than the first. Then the fun started.
The third stud broke just proud of the head. I thought it was a fluke so I kept going. The fourth stud broke just even with the head.
After that I was done being nice. I ran a 5/16" drill down a 5/16" nut so the nut would slide down over the next stud, then broke out the MIG welder and welded the nut to the stud. The heat broke the stud free and it unscrewed without drama. At the end of the day I was 12 full studs out without too much violence. The other 6 studs refused all efforts to come out after welding a nut to the part stuck in the head. I ended up using a small grinder bit in my Dremel to flatten the top of the exposed studs, center punched the stud, and carefully drilled them out starting with a 1/8" bit and going up 1/32" until I got to the 5/16" bit. I then drilled and tapped for a 5/16-18 thread repair.


I was slow and deliberate with the drilling but I shouldn't have to worry about this going forward.

 

Glyn,
Are you suggesting putting the AC evaporator core in the heater box?
Thomas

 

Yes Thomas. because you are throwing out the heater "radiator" etc & numerous flaps etc. The evaporator in a modern Mercedes is no larger than Jaguar's heater radiator. (heat exchanger) and will freeze your male parts off.

It baffles me that the car industry has not moved to bi directional heat pumps like the domestic air conditioning market has. Either stuck in the past or a cost issue. My LG Inverter V heat pumps do a great job throughout my house. Heat in winter, cool in summer. Went for independent split units so that I don't heat or cool areas of the house that are not in use. e.g. Lounge, Kitchen, Dining room, Hallway are interconnected & can be isolated by the closing of 1 door to the passage way & stairwell that serves all the bedrooms, bathrooms, Indoor Jacuzzi Room & Home Theatre. One 24,000 BTU split unit can keep that area at any temperature you want. Hot or cold. Of course this route would require investigation of the condenser requirement. I can't believe that this cannot be overcome. Modern large cooler boxes with plate coolers have no difficulty in this regard.

If I want to keep the main bedroom and en suite bathroom cool in Africa's hot summers we just switch that 12,000 BTU unit on & save energy on the rest of the house while comfortably in bed.

The interior area of a car is comparatively small. I do not understand why OEM's have not investigated the domestic route. Maybe since the heat source is effectively free due to lack of efficiency of the engine. A Benz F1 car engine is now > than 51% efficient. Domestic cars approx half that.

Yes you would be breaking new ground unless some aftermarket A/C company has done it already.

 

Glyn,
Your house doesn't sit in the sun getting up to 170F+ in a parking lot in under an hour. Cars/SUV's can have 2.5 ton + of A/C capacity to cool down the discharge air to under 90F in less than 5 minutes after the engine starts. You have to remove the thermo load from all of the interior so that the occupants will feel comfortable in a very short time. A house remains under a very narrow temperature range where a vehicle operates with interior temperature ranging from 200F+ to -40F and below. A car has to perform under very severe conditions compared to house.

Some cars have heat pumps but the A/C & heater performance is only OK. They are making improvements but is not a simply solution and it cost much more.

I work for the last 30 years of my 42 year career (prior to retirement) designing HVAC systems for one of the big 3. I worked with all the supplies from Behr/Halla/Delphi/Denso etc. Behr and Denso supply Your favorite auto company and the newer Mercedes isn't any better than other Denso systems.

What is the size of the Mercedes evaporator? 10"x12"? Not a small heat exchanger.

That's all I have to say.

 

Excellent ~ You always pop up on matters HVAC. Thank you for confirming the cost element. Time & technology development move on more quickly than you may think. e.g. my comment on a Benz F1 V6 1.6 litre capacity engine now exceeding 51% thermal efficiency. A Benz evapourator is approx the same size as the Jaguar heater radiator (S Type) and yes it is a micro encapsulated Nippon Denso, Behr or Valeo unit as is the swash plate compressor (Denso). Porsche uses Japanese Aisin manual transmissions. We live in a global world. The US is well known for barn door engineering. 7 litre inefficient V8 engines in today's world and I'm staying away from the V10's! as they are few by volume produced.

We both know that the majority of cars are of small interior volume when compared with a house. This creates a huge offset and Africa's sun can heat a house to unpleasant levels pretty quickly. No double glazing here etc.

 

There's definitely a difference in our requirements from a/c. That initial big blast of cold air is something that's very desirable in car systems, less so in domestic. It's something the old Delanair box in the series XJ wasn't very good at. My hope for my Mk2 is to remove all the original under bonnet system and put an integrated a/c and heater inside the car on top of the gearbox. At present, I've no idea if that would be a something borrowed from another car or one of the systems sold in the UK for kit cars. I have to admit that refrigeration is not something I've done any calculations on since the last time I tried to teach some thermodynamics a few decades ago.

 

I still have my textbook on Heat & Thermodynamics by Zemansky somewhere in this house.

 

I remember that one. The classic for engineering was 'Analysis of Engineering Cycles' by R.W. 'Dick' Haywood, ace book by a real engineer. He was also a brilliant lecturer.

 

You just can help insulting people can you.

Have a good Day

 

No insult intended. A quote from Jeremy Clarkson Supposed to be humour.
I apologise if taken in the wrong context/spirit.

 

Bob S
The concept of "barn door engineering" as far as I know came from a well-known aeronautical statement that" if you put enough cubes (displacement) into the engine then you can make a barn door fly."
That is essentially true and nothing to get too excited about. In aviation it is a fact of life. You need "cubes" to make it fly
I have flown numerous piston engined aeroplanes with what would be alarming cubic displacements compared to the average motor vehicle owner.
My Piper Cherokee has a 540 cubic inch or 9 litre engine developing 235 HP at 2500 RPM. later engine versions go to 300HP
My ex-military CAC Winjeel has a 985 cubic inch engine or about 16 litres developing 450 HP at 2300 RPM
I used to fly an ex-air force Lockheed Neptune maritime patrol bomber(P2V7) and its engines were 3350 cubic inches or 56 litres developing 3700 HP at take off with water methanol injection
I think barn door engineering is great
Cheers

 

Thanks for that Bill. Extremely interesting & no doubt where Clarkson inherited the expression from, although it's a common statement even in SA. And yes I did my compulsory, at the time, military service in the SA Air Force where we were treated extremely well. We have built a very long string of Aircraft in SA under license. Many Dassault Mirage variants with an SA touch added. We even designed & built our own attack Helicopter. The Denel Rooivalk. Wikipedia covers just how long that list was. Some of it reverse engineered.

Quite a lot of heavy military equipment has been designed and built here. Much for international sale. We even built our own version of Gerry Bull's long range gun here. Ever remember a nuclear explosion detected miles from nowhere over the Southern oceans. Well that was us fired from our own version of Gerry Bull's gun. We did not want to handover any nuclear capability to a new Government.

Before the end of the disgusting Apartheid era we handed over all our nuclear development to the US, Israel & other countries & repurposed the facilities at Pelindaba into something useful.

 

Barn door engineering is something that I can ramble on about for pages, at risk of wandering off topic. Bill’s already captured the origin and essence. However, the concept is very wide in engineering and beyond, running into topics such as optimisation and customer service. A structural engineer would call it reserve strength, the reserve beyond his original design load. It can arise from design codes, designer discretion, feel good, rule of thumb. Jaguar used it in their suspension and subframe designs when they applied good old gun barrel load factors to resist fatigue. It’s one of the reasons that our old cars are still around in spite of neglect when they were unfashionable and why they keep going when half broken. It’s a concept that Colin Chapman never took to heart, preferring to optimise to death. A Lotus F1 spaceframe should fall apart as it crossed the finish line, which carried the obvious risk of not reaching the line. There was never a Lotus-Jaguar; no big lumps of cast iron for Colin.

In a completely different context and totally off topic, anyone who has flown through London Heathrow airport has probably experienced the downside of optimisation, the absence of the barn door. The place operates at 99.9% of capacity. The proverbial butterfly lands on a runway in South America and the 2 second delay throws Heathrow into chaos for the rest of the day.

In summary, I’m all for the barn door. So long as it stays within reason, leave the margins.

 

Talking of the Colin Chapman acid dipped Lotus Cortina's. When passing the pits, he used to instruct his drivers to use one arm to hold the roof up as it used to dip inwards at speed. Anyway ~ we are now thoroughly OT

 

Tonight I started designing what the brackets for the alternator and AC might look like. It's much easier to make some cardboard templates until I figure out exactly how it's going to look. I've removed the factory alternator mount and I'm thinking about using a piece of plate steel as the base for the alternator and AC compressor.
Using two original alternator bracket bolt holes and the top of the motor mount, I think I will have a strong base to start from.



Spacers on the top two bolts allow for the different elevation of the alternator mounting holes and the top motor mount hole.


My metal order should be here this weekend and I can start version 1.0

 

Bill, I'm in no way anti American. I worked for an American oilco for my entire career, lived there ~ Dallas & Bay Area and my entire Audio/HT system is American & with speakers the size of a barn door ~ Magneplanar with ribbon tweeters & Bi amped. Each of the many amplifiers required to achieve this weighs very close to 100Kg's & is made in the good old USA. The pioneers of high end audio.

Now back OT ~ we are messing up Thomas' thread. And that includes me!

 

Agreed we should get back to the original thread. (OT?) . I am still trying to catch up on these "new speak" acronyms.
But there are times when a bit of drift lightens up the sometimes dead set serious problems being expounded (and possibly entertains.)
And I think Thomas is possibly way ahead of the average subscriber to this thread in his engineering knowledge and application.

 

OT = On Topic

 

OT can = Off Topic or in the sense I was using it on topic as Norri kindly explains.