DRL152K Marina based roadster rebuild

[martinclan56]

Whilst I think about how to best make the bonnet tops I have been working on a few other items.
The exposed section of the exhaust is pretty much complete now. As it passes pretty close to the inside of the rear wheel I decided to mount it close and rigidly to the chassis. My theory is to allow for engine movement by adding a flexible section, where it passes under the car, to meet up with the downpipe. That's the theory anyway... The silencer ended up in a pretty much perfect place following the chassis line but a few mm away, enough to get some heat shield in I hope. The tail end exits nicely under the rear wing. I will shorten that and add some sort of bend so that the exhaust gases don't end up fouling the chassis.
exhaust1 by Robin Martin, on Flickr
exhaust3 by Robin Martin, on Flickr
rear_lights1 by Robin Martin, on Flickr
As you can see I have also mounted the rear lights. They are Lucas and are nearly a perfect fit. Actually about 2mm to wide but it doesn't really notice.
I have also fitted the doors with door cards so I could check the fit of the door seal I chose. Door also misses exhaust which I always planned but you never know....
door_card1 by Robin Martin, on Flickr

[martinclan56]

I had always planned to make new bonnet tops as the original ones were rather scarred to say the least. I thought it would be relatively simple to use the old ones as a template. However....

I trial fitted the old one last week having cut it in half as the new one is to be hinged in the middle. The fit is absolutely awful. In fact it's so bad I am beginning to wonder if it was for another variation of the car. It is particulary bad at the scuttle end where it is a complete missfit. So, first I am going to have to do some serious fettling fit before I can even consider using it as a template. You can see from the picture just how bad it is....
bonnet1 by Robin Martin, on Flickr

And, in addition it is also too wide at the scuttle end. You can see the overlap of the two halves in the picture now I have sliced it in half. I will have to take about 10mm out of the width plus the width of the piano hinge. Strangly the other (radiator cowl) end it is the correct width.
bonnet2 by Robin Martin, on Flickr
If there are any original builders out there, can you remember having such a problem?

[martinclan56]

Going back to steering wheel, the Roadsters we have owned have had smaller steering wheels than a Herald fitted, 12 or 13 inch more common. Liz

My previous roadster was fitted with a 13 inch wheel. The Triumph steering wheel is actually only 15 inch so only 1 inch bigger in radius. It just looks huge in the picture. Nevertheless I will make sure I fit it!

[lizbillings]

Going back to steering wheel, the Roadsters we have owned have had smaller steering wheels than a Herald fitted, 12 or 13 inch more common. Liz

[martinclan56]

Thanks Jon. That's something I hadn't considered. Although I don't do much spirited driving nowadays I'll certainly look at fitting a panhard rod. There is aready more clearance than normal between the tyre and chassis as the wire wheels add over an inch to the track. But nevertheless I can see how extreme movement of the axle may cause contact.

Cheers, Robin

[jon_cox]

And I have been thinking about the exhaust route. I was always going to have a side mounted silencer but I would like the actual output to be at the rear of the car - not by the passengers ear. It looks like I should be able to route it between the chassis and the rear nearside wheel. Again - what do people think?
exhaust_1 by Robin Martin, on Flickr
[/QUOTE]

You would probably want to consider the fitting of a panhard rod assembly to guarantee no interference. It is surprising how much the axle moves laterally under spirited driving. Also, keeps the wheels vertical as a hard right hander could see the axle move closer to the exhaust plus the angle of the wheel and you have contact.

This setup is however used by other manufacturers. Caterham, Morgan and Merlin have used this in the past. I think the Merlin used an oval pipe to give more clearance.

Another option would be to take the pipe under the car, between the spring and the chassis just in front of the rear wheel and over or under the axle. The original Marina exhaust went over the axle.

[martinclan56]

Can you get your knees under the steering wheel, especially when the seat is in?
Following your build with interest. Looking good
liz

Haven't tried that test yet. I am vertically challenged haha - even so perhaps I better do that next.

[lizbillings]

Can you get your knees under the steering wheel, especially when the seat is in?
Following your build with interest. Looking good
liz

[martinclan56]

---

I have completed the other bonnet side. Took less than half the time of the first one!
The bad news though is that I trial fitted the old bonnet which I was going to use as a template to make the new one. It is an awful fit - in fact it doesn't really fit at all. So I am going to have to fettle that first before I can even consider using it as a template. Hmm
bonnet_side_3 by Robin Martin, on Flickr

As a bit of an asside I have been doing some planning. I am considering using this steering wheel. It's an old Triumph (Herald?) steering wheel and is dished and has sprung spokes the idea being it does provide some protection in the event of a prang. What do people think?
alternative_steering_wheel by Robin Martin, on Flickr

And I have been thinking about the exhaust route. I was always going to have a side mounted silencer but I would like the actual output to be at the rear of the car - not by the passengers ear. It looks like I should be able to route it between the chassis and the rear nearside wheel. Again - what do people think?
exhaust_1 by Robin Martin, on Flickr

[listerjp2]

Looking good

[martinclan56]

I have made the first of the two bonnet sides. A lot of carefull measuring involved as it is a big panel and didn't want to cock it up. The front and back edges are parallel but top and bottom are both set at an angle. The bottom to follow the chassis and the top to giving the bonnet a pleasing drop towards the front. The original panels were shot but useful as a double check.

The original bonnet side has a lot of folds at the edges not really necessary for strength. But I came to the conclusion that it's actually a clever part of the design - the folded edges are what you actually see which means the 'orrible cut edges are hidden. Which is just as well as the originals seem to have been cut out with a jigsaw with the edges left rough. All done for speed of course. Anyway I made the replacement exactly the same way (I did clean up the edges), the only difference being I riveted the ally angle that strengthens the top rather than nut and bolting it in place as per the original.

It would be an understatement to say I am pleased with the result :-)
Just the other side and the bonnet tops now...

bonnet_side_making by Robin Martin, on Flickr

bonnet_side_1 by Robin Martin, on Flickr

bonnet_side_2 by Robin Martin, on Flickr

[martinclan56]

The Roadster chassis is massively over engineered, the main rails being 100x50x3mm box section. A few small holes really won't make much difference.
Had it been one of the later Marlin designs, in which much of the chassis is constructed of lighter gauge folded steel, I agree it could be a problem. All IMHO of course :-)

[Neil Johm Kirk]

Hmmm, issue always is that in drilling the chassis to fit rivnuts for your spare wheel bracket you are also introducing potential weakness. If it wasn't on the side of the main chassis spar, it wouldn't necessarily be an issue; but it is.

[martinclan56]

I am a bit paranoid about carrying a spare, not convinced that the squirty tyre repair stuff works! And if if you have a puncture it's always at the most inconvenient time and place, raining, middle of the night and miles from home....
My theory with the rivnuts is that even if they allow water penetration and long term rusting of the chassis it will still well outlive me lol.

[andyf]

If you're going cycle wings and don't want to have the spare on the rear tub I wouldn't bother with it at all, I think it would look much better without a spare on the side, but I know that's subjective...

The radiator mount looks nice and neat. Rather than drilling into the chassis I welded tabs on that I could bolt the radiator mount to, just a thought