DDK - Die Deutschen Klassiker

Continued with my little oil cooler project.

I had been thinking for a while what type of cooler to get. the 69-89 911 had no less than 5 different cooler variants that I know of, all of which have their supposed plusses and minuses. After a bit of research I went for the often forgotten about 28 bar brass cooler. You hear very little about these because they were one-year-only in the US in 1984, and the vast majority of info out there is US based, but they were std on euro cars from 80-84 as far as I know.

I went for this because the two earlier options were either stupid money (69-71 cooler) or considered worthless (72-79 trombone) and the two later coolers had their own issues. The early fan-less 85-86? carrera cooler allegedly needs good air flow to work (i dont think airflow behind my battery box and horns etc will be great) and is not so good in standing traffic, (I think this is the most pertinent time I would need a cooler), and the later 87-89 carrera cooler with a fan would be a difficult install. Having fitted my 28 bar cooler I think a carrera cooler with a fan would actually be impossible to fit without cutting out the battery box.

The advantages I saw in the 28 bar cooler were that 1) I got one for cheap (always helps) 2) it works best in standing traffic as it is a heat sink design cooler, 3) it feels like its made from wrought iron and certainly doesnt need a protective grille, so taking it in and out will be much easier, 4) it was made for the 3.0/3.2 engine so should still have ample cooling capacity for me.

The cooler I got has been cleaned and pressure tested and looked like new. I mock installed it in the arch with an axle stand to support it. I then got a factory cooler lower support bracket to fit it. I assume this bracket is for later cars or whatever as it fits the cooler but not the profile of my car chassis. I had to cut it all up and modify it in order to do the job and weld it in place. Its not the prettiest welding job but it will hold about 10 coolers if needed. Welding on your back, on axle stands, with red hot melt dripping on you, with a cumbersome helmet and gloves and no light and etc etc is not easy. You can see how close this is to the horn and battery box, theres no way you would get a fan in front of this.






With the bracket installed the cooler fits perfect. That is until I fitted the wheel.... And turned it to full lock... With the wheel in the air at full lock it was mere mm from hitting the cooler. There isno way I could possibly move the cooler any higher or further forwards... Surly once the suspension is compressed it will be mashing the cooler completely... fortunately what I forgot was that as the suspension compressed on a lifted wheel the wheel moves up but also outwards. Thus as the car is dropped rather than getting closer to the cooler, the wheel moves away. It is still pretty close though! Needless to say if I had a fan assisted cooler theres no way it would clear the wheel.





With the front end done I moved to the back. The M30x1.5 fitting on the oil lines are naturally a pain in the arse. I needed custom hoses to mate my late oil lines to my early oil console, and no aftermarket hydraulic companies supply these almost obsolete fittings. I had to get 4x adaptors to AN16 for each end of my two hoses. With these adapters and the required fittings (2x 90degs and 2x 60degs) I was able to make two hoses to fit. The only thing left to do was bleed them.

I did wonder about when installing an oil cooler how you fill the whole system with oil. You could wait for your engine to get hot and need the cooler but then it would lose 3l of oil from the tank to the previously empty cooler system, which doesn't sound like a good idea. So I decided to fill the system with oil before connecting. Easier said than done, it required a lot of messing around, oil getting everywhere, physically blowing oil through the lines, in short it was a nightmare but I got there. I pray to god not to have to take this back out now that its full of oil, doesnt bare thinking about.

As an aside, I've fitted, re-fitted the trombone lines and cooler (from a 2.4S) to my 911T/3.2, all Porsche parts and have never bothered with pre-filling the pipes/cooler but simply get the engine hot and keep an eye on the level as it warms. The heat of the hot oil obviously travels to the front as the stat opens.
When untouchable you know those side pipes are full and check the dry sump tank is between Max and Min when temp is all stable.

After first road run when back check level again and all is well.

With these things I just estimate how the factory did it. They wouldn't surely do all that on a 70's production line?

911hillclimber wrote:As an aside, I've fitted, re-fitted the trombone lines and cooler (from a 2.4S) to my 911T/3.2, all Porsche parts and have never bothered with pre-filling the pipes/cooler but simply get the engine hot and keep an eye on the level as it warms. The heat of the hot oil obviously travels to the front as the stat opens.
When untouchable you know those side pipes are full and check the dry sump tank is between Max and Min when temp is all stable.

After first road run when back check level again and all is well.

With these things I just estimate how the factory did it. They wouldn't surely do all that on a 70's production line?

I thought this would be the best way really but my engine doesnt get hot enough just idling in normal temperatures. I have read about people putting a towel over the engine grille to make the engine run hot, but im not sure how good an idea this is. So maybe I could have done that, which would have saved me a lot of time and effort!

Tyre to cooler clearance - I would have a slight concern that some"thing" of suitable size may get picked up or thrown up by the tyre and could get wedged in a decreasing gap as it falls (gets pushed down by rotating tyre) ... with consequences you don't want to think about. Solution : Not so easy - but could some form of scraper / deflector plate be fixed above to prevent this ?? (just thinking out loud)

Ref filling the cooler.
It is hard to get a 911 to get hot enough I agree. If the ambient is less than 22 say, it may not open the front cooler.

As to the tyre clearance, it sure is close. When I was in automotive (body-in-white) the rule of thumb was a thick finger clearance was a minimum.
Doesn't the 3.2 have a plastic vented shield on the exposed/tyre face?

Cooler :
Post 74 cars had more room in the front wheel wells as they did not have any battery boxes like the 69-73 cars (except factory race cars).

The 28-bar brass cooler is the first I've heard (you did a good research) and it sounds like a very good alternative to the trombone but as you said it's too big, so why don't you get a brass fabricator (Ben Coles?) to make a smaller one to fit in the same mounting points as the 69-71 cooler?

Cortina wrote:Tyre to cooler clearance - I would have a slight concern that some"thing" of suitable size may get picked up or thrown up by the tyre and could get wedged in a decreasing gap as it falls (gets pushed down by rotating tyre) ... with consequences you don't want to think about. Solution : Not so easy - but could some form of scraper / deflector plate be fixed above to prevent this ?? (just thinking out loud)

You make a good point! I have taken a second look and the clearance issue is really only at 100% full lock where it is about 1/2 inch, I have 2 inches clearance when the wheels are straight on which obviously goes down to ~1.25 inch at half lock. Unlike you rally drivers I really only ever use full lock when getting off my drive! and I wont be throwing up any stones at 2mph I think I have enough clearance to be confident itll be fine. Nothings impossible but I think it is very unlikely to happen (touching wood as I type!)

The photos I have seen of others installing this dont use any kind of guard, I dont think it really needs one other than to keep mud building up in it. But you may be right that the factory cars that had this cooler had a plastic guard, I will look into this.

I guess if this cooler ever does get holed I will end up looking for a bespoke option after all! Good to know there are people out there who could make one.

Thanks for the advice guys!

knapmann wrote:

Cortina wrote:Tyre to cooler clearance - I would have a slight concern that some"thing" of suitable size may get picked up or thrown up by the tyre and could get wedged in a decreasing gap as it falls (gets pushed down by rotating tyre) ... with consequences you don't want to think about. Solution : Not so easy - but could some form of scraper / deflector plate be fixed above to prevent this ?? (just thinking out loud)

You make a good point! I have taken a second look and the clearance issue is really only at 100% full lock where it is about 1/2 inch, I have 2 inches clearance when the wheels are straight on which obviously goes down to ~1.25 inch at half lock. Unlike you rally drivers I really only ever use full lock when getting off my drive! and I wont be throwing up any stones at 2mph I think I have enough clearance to be confident itll be fine. Nothings impossible but I think it is very unlikely to happen (touching wood as I type!)

The photos I have seen of others installing this dont use any kind of guard, I dont think it really needs one other than to keep mud building up in it. But you may be right that the factory cars that had this cooler had a plastic guard, I will look into this.

I guess if this cooler ever does get holed I will end up looking for a bespoke option after all! Good to know there are people out there who could make one.

Thanks for the advice guys!

I think you'll be fine - it looked tighter in the photo (engineer .... need facts and data !!)

I run a rear mounted oil cooler on my SC. There's a bit about it here:

https://www.impactbumpers.com/forum/ind ... r-project/

.

I've had 2 (modified) early cars in the past fitted with the 28-row brass oil coolers but in both cases the battery box was removed on that side as I always ran my cars with a single battery.

The benefits of these coolers are that they are (relatively) cheap & not easily damaged.

I'm sure you'll be fine.

.

I’ve done a similar job on my SC which just had the trombone cooler and it seems to work well in all conditions, especially when air flow is limited. Did you manage to fit the top mounting which attaches to the rear of the headlight bowl, I only ask because I considered not doing it due to a lack of the welded fitting on the reverse of the headlight bowl? But I realised the cooler moves around a bit more without it and so decided to fit one. Worth considering.

Ian

Ian Comerford wrote:I’ve done a similar job on my SC which just had the trombone cooler and it seems to work well in all conditions, especially when air flow is limited. Did you manage to fit the top mounting which attaches to the rear of the headlight bowl, I only ask because I considered not doing it due to a lack of the welded fitting on the reverse of the headlight bowl? But I realised the cooler moves around a bit more without it and so decided to fit one. Worth considering.

Ian

At the moment I havent fitted one, it seems pretty secure to me without one, obviously there is flex in the rubber hoses to damp vibrations and they are stiff enough it seems to also hold it in place. What I did do is clamp the brass oil lines to the body as close to the neck as possible to reduce the ability of it to move around. I will see how it goes like that for now.

Jonny Hart wrote:I run a rear mounted oil cooler on my SC. There's a bit about it here:

https://www.impactbumpers.com/forum/ind ... r-project/

I have seen this in one of your videos it looked like a great solution if you need a lot of cooling. The only problem I had with it for me was that as my early oil console exits the engine bay on the RHS I would need to run 2x lines under the engine/gearbox to the other side, this would then make taking the engine and gearbox in and out a pain in the arse. I could have changed the lines on the console and ran them around the back of the engine bay to exit on the LHS of the bay to solve this but this would not look original either (not that my sill mounted lines look correct). In the end it seemed simpler to use factory parts which I managed to source for a reasonable price. If however I was struggling to get factory oil lines for example this would be another reason to go this way.

You sure get good advice on do
Now you say 2” clear dead ahead lots of room for a classic use car

911hillclimber wrote:You sure get good advice on do
Now you say 2” clear dead ahead lots of room for a classic use car

Hmm ..... I am kind of hoping this post may also be available in English soon (sorry , I could not resist ..... leg pulling !!) I may try and stay quiet now .... off to sunny Wakefield on the 0730 boat tomorrow , to collect new car (and leave old one behind) ............ and before you ask , the boat does NOT actually go to Wakefield !