Beck TD, Part 85 - A New Radiator!

 One of the consistent threads of Beck TD's 7-year story in my shop has been "messing with the cooling system." In the early days, just getting the radiator and hoses sorted took effort, and since then, the cooling system has been barely adequate on hot days. In Part 82, I went to significant expense to make some changes to the radiator, and while it improved the fitment and look, it still ran hot on 90+ degree days in city traffic. That 70-year-old radiator just wasn't up to snuff!

Members of the Volvo Engined MG group had identified a replacement radiator for sale on eBay from Winner Racing that looked promising, and one member had contacted them to request a custom version for our Volvo application. Their response was, "Sure - just tell us what you need!" I contacted them, and across several emails we worked out a custom version that I bought. In the photo below, their stock TD replacement is on the left, and my custom design is on the right. You'll notice several changes, including a flat tank, relocated inlet and outlet, a custom filler with pressure cap, and more. 

They made the radiator very quickly, but shipping took several weeks. Most of that time, as far as I can tell, the radiator sat in US Customs. It was around Christmas time when it was shipped, so maybe that had something to do with the delay.

I had to make a number of modifications to get the radiator to fit correctly. I have no way of knowing if that's because of my modified car, but I think it's reasonable to expect some extra work to get it to fit in a decades-old hot rod.

In this photo I have the new radiator suspended in place by that brace that runs between the headlights. That's a stock MG design, and is a "hard point" that must line up. Notice the bottom of the radiator - it's a bit too high.

See that stud on the bottom of the radiator? It is threaded on the bottom, and both locates and holds the radiator in place. The base of the radiator should be flush on that rubber donut, but I had about a half-inch gap.

Here's a comparison with the old, stock radiator, which sits flush when installed the same way.

This bracket on the Winner radiator is where that cross brace mounts. The brass inserts are called "rivnuts", and they are in the wrong place for my car.

I ground them flush, and carefully located and drilled new holes to mount the bracket. I just used nuts and bolts to mount it, because I needed that clearance due to my electric fan.

An earlier version of this post mentioned that I also needed spacers at the other end to make that headlight bracket align correctly also. I later realized that that was not correct. I was able to use brute force to make the bracket roughly align, and then use the mounting screws to draw things into place. I was simply confused because the old system lined up without that drama! But my bonnet ("hood" in American English) would not align correctly until I did the brute force thing.

In my car, at least, none of the mounting holes were quite right. In the foreground below, you see the beat-up slot in the original radiator. Behind that, the Winner radiator had a slot, but it wasn't close and I had to drill another hole. I had to do that for all 8 grill shell mounting holes.

The next modification was not necessary, it was just something I wanted to do. I had specified that the original radiator fill location be mounted for the stock external radiator cap, but the hole not drilled through, since I had a new fill location with pressure cap. I decided I wanted that neck to be mounted on the grill shell for perfect alignment, so I got bold and cut it off!

On the lathe, I turned a neck on a great big piece of aluminum that perfectly matched the neck I cut off. This was used to make a base for the neck.

Here's the finished base and neck. You can see the two set screws I added to hold things together.

I also made a precise spacer to ensure that everything was tight and aligned. The piece on the left was similar to the raw material that became the ring on the right.

Here's the completed neck, base and spacer.

And here it is permanently mounted on the shell. Again, this step was not really necessary, I just wanted to do it this way. 

One concern we had when  designing this radiator was whether the new pressure cap would intefere with the bonnet (the "hood" in English). That's my friend Troy's finger, showing that it clears just fine. Another member of the Volvo-Engined MG group did have clearance problems until he modified his mounting holes to move the bonnet up a bit.

The lower hose fit well enough - the slight flattening was there with the old radiator also.

The top hose is custom. Jake R. convinced me that I should use a silicone hose because they are so flexible, and won't put undue stress on the neck. To get one long enough, I had to buy a right-angle hose with 10" legs, and cut it to fit.

After a bit more trimming, I had a good fit and a leak-free connection.

At this point, the system was complete and I ran some tests. I was very happy with the results! The radiator was leak free and cooled very well in tests in the shop. The only problem was that the location I chose for the electric fan sensor, in the top tank of the radiator, was not right. I decided to move the sensor to a location on the cylinder head, where there was already a small blocking plate into the water passage just below the thermostat housing. In the photo below, the stock plate is lying flat. It is 0.150" thick, and I wanted a bit more "meat" for tapping the 1/8-27 NPT threads for the sensor. The material I uses was 0.230" thick, and I was able to get two plates from that small piece of scrap stock. Notice the punch mark above the center holes - that's to identify the front (outward facing) side, since the NPT threads are tapered. 

And here's the sensor in place on the engine.

One more test, and all seems well. The engine reached 185 degrees at the point the sensor triggered and turned the fan on. On a 65 degree day, just the fan was enough to cool the engine back to 168 degrees. Now all we have to do is wait for hot summer weather for the final test! I am very pleased with my Winner radiator, even with the extra effort to get it to fit my custom application.

Continue on to Part 86....