TR7 & TR8 Forum

I would really like to upgrade the fuse box from the glass fuses to blade fuses, has anyone tried or done that?

I do not know about a TR7 but I installed a blade box on my TR6. I got it from Amazon, it is a 6 slot one so I have two spare slots. Put it where the original was, no issues. I hope this helps.

The seven has lots of relays and switches, more than any other Triumph. If I were going to spend time rewiring, I might consider something that also has built in relays for the headlights and everything else. It would be a big project though.

I started doing this and it is in fact a big job. But when it is done it'll be (hopefully) well worth the effort. I'll take some pictures tomorrow if I can.

I had the loom out of the car and did this:

It tested out ok on the bench and now that its in the car, everything so far seems to work, although the car does not run yet. (Part of a V6 swap from a Camaro that I've been working on forever.)
I can get part numbers if you're interested further; I did this awhile ago and would have to look them up. I remember that I struggled trying to find something that allowed the wires to be connected straight in from behind, as opposed to coming in on an angle from the side.

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Brent

Part numbers would be very helpful. Thank you Brent. Looks great

I went with a six relay box with fuses. It's a bit too big to fit under the dash or in the glove box but it is a decent little unit. I out mine under hood next to the ignition box I added.

I got it on amazon. It's not waterproof, but I'm not doing any rally events or going mud bogging in the car. I don't think it will be a problem. They are cheap and come with all the little crimp on connectors you need to get the job done (no extras though so be very very careful)

I bought them through Del City.

https://m.delcity.net/store/ATO/ATC-Block-!-8!Way/p_10823.h_26531

To fit in the original location the direction the wires come into the fuse panel is important and these ones fit well without having to make very many modifications. As I remember, I think i Dremelled away some of the metal bracket.

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Brent

I meant to post this when I first saw this topic. Traditional Lucas fuse ratings are not the same as
modern fuses ! If you want to protect your wiring, check the fuse rating very carefully.

Fuse Ratings

Lucas fuses______Modern rating
50 amp__________25 amp
35 amp__________17 amp
25 amp__________12 amp
20 amp__________10 amp
15 amp__________8 amp
10 amp__________5 amp
2 amp__________ 1 amp


Cheers

H



Edited 1 time(s). Last edit at 2019-08-21 04:15 AM by HowardB.

The TVR 280i was basically a TR7/8 with a fiberglass body when it came to electrics. Even used the same headlight motors, column switches, and a bunch of other stuff. It used one of those kit car looking blade type fuse panels. Pretty much looked like a TR7 wire harness with a different panel. Don't remember ever having any electrical issues with that car. Its problems seemed to be confined to rear suspension quirks, and that unit was from a Jag with a bad layout of control arms. I'm planning on a Painless wiring harness or similar knockoff for the LS3 powered coupe, but as of now, there will be zero creature comforts in the car. The Painless sytem will give me the ability to expand later on if I so choose.

Howard:

If you are not aware, the difference in the fuse ratings is due to the agencies used to rate them.

Lucas fuses use the DIN standard (German industrial standard) which rated fuses at the current guaranteed to instantaneously blow the fuse.

US fuses use the UL (Underwriters Laboratories) standard, which rates fuses at the maximum current the fuse will carry without ever blowing. The current generation of blade fuses are also rated at the maximum continuous current without blowing.

And yes, to translate between the two rating systems, one multiplies the DIN rating by 0.5 to arrive at the approximate UL rating. Always a good thing to remind people, and inform the newbies.

As far as the glass cartridge fuses go, the UL fuses will normally be slightly longer than the Lucas fuse. US glass fuses of the standard variety are 1.25 inches long, while Lucas fuses are 30mm, or 1.2 inches long. In my TR8 it is not possible to insert a US fuse into the fuse box (OK, if you use a hammer, you can make it fit, but otherwise...)

Vance

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1980 Platinum Metallic TR8, frame off restoration, complete.
1974 Jensen Healey, now assembled and awaiting startup. =:-)

Vance

I would be surprised if the DIN standard applied to GB fuses made in the 1960's & earlier since they would have been covered by a British Standard at that time (sorry I can't locate the BS reference)

As you say, the main problem is that most TR owners do not know that there is a difference in ratings between modern blade fuses, as discussed in this thread, and the traditional Lucas fuses.

Howard

Howard:

Can't offer a comment on that. All I can say is that my 1974 TR6 and my 1980 TR8 came stock with DIN rated fuses. Prior to 1974, they may have been Imperial, SAE, UL, DIN, JIS, Klingon, Romulan, or...?

Just glad you brought it up, as it is important. I took a blown fuse from my TR8 to my FLAPS, and asked for a replacement. He tried to give me a UL rated fuse which not only would have set my wiring on fire, but was also too long to fit. I had to inform him of the differences and asked if he had an equivalent. Nope.

Ended up ordering several different fuses from BritishWiring.com. They were proper English fuses except for one set which was, you guessed it, UL fuses! I had to inform the proprietor of the differences, and he went and checked his stock. Sure enough, he acknowledged his supplier had screwed up and shipped him a batch of UL fuses instead. So it is important and needs to be repeated often - even for people who should know better.

Cheers from across the pond,

Vance

P.S. Don't forget Murphy's law Corollary #86: A $300 wiring harness will always spontaneously combust in order to protect a 10 cent fuse.

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1980 Platinum Metallic TR8, frame off restoration, complete.
1974 Jensen Healey, now assembled and awaiting startup. =:-)

Vance

Even further away than you guessed. Currently living in Qatar and while there are some interesting preserved cars here, sadly no TR7's

Cheers

What?

But, but, but you have a union jack indicator for your country of origin.

Oh, I get it. Like James Bond, when abroad you are still in the service of the queen.

Kewl.

Vance

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1980 Platinum Metallic TR8, frame off restoration, complete.
1974 Jensen Healey, now assembled and awaiting startup. =:-)