Swapping a 5 spd for a 4 spd - speedo change?

[Mowog73]

I just purchased a 76 TR7 FHC as a father/son project and will be towing it home this weekend.

This car does have a 4 spd in it but a friend has offered me a surplus 5 spd. Now I know that the diff is different between the 4 spd and the 5 spd cars but where the speedometers different as well in terms of “turns per mileâ€￾, in other words, do I have to find a speedometer used with a 5 spd in order to have actuate mph (km/h).

Thanks for the help.

Mark
SW ON


Better to burn out than fade away

[Odd]

You calibrate the speedometer by swapping the driven gear (or if that's not enough) also
driving gear in the gearbox. What rear axle ratio and wheel/tire combo are you planning
on using?

There were two driving gears available: 7tooth White TKC1273 and 8tooth Black TKC1274.
They could be combined with one of the six driven gears: 20 Orange 219001, 21 Green 219002,
22 Red 219003, 23 Black 219004, 24 Blue 219005 and 25 White 219006.
All depending on what rear axle ratio and wheel size is fitted to the car.

PS
(A 19 would have been a heaven sent gift, but no...)

[Mowog73]

At this moment I assume the original rear axle is present but would probably want to swap it for a 5 spd rear axle. Also the plan is to stay with the original 187/70R13 tires.

Better to burn out than fade away

[MickeyR]

Hey, Mark -

Which one did you get?

Mickey

[RJS]

This topic on speedo drive gears was VERY helpful to me.

http://www.forum.triumphtr7.com/topic.asp?TOPIC_ID=6672

Rob

[Mowog73]

Hi Mickey

We're going for the two cars, 76 with a very good body and the V6 in it and the 77 parts car. We'll be getting rid of the Firebird V6 and putting the proper engine and 4 spd tranny in from the parts car. Definitely want to convert to a 5 spd setup.

We're going to get the parts car this weekend and we may try to start it. The other car won't becoming home until the Spitfire is paint, homefully within a few weeks.

Better to burn out than fade away

[KLUTZP]

Hey fellas... Watch this Mowog guy...
He is the one who broke MY TR7. [:D] Much to silver7's gain. Toss out those MG books Mark cause I have a pile of TR7 books for ya, and lots of new words.
[:)]
Paul

[Mowog73]

Thanks Rob, that's a good one.

Mark

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by RJS</i>

This topic on speedo drive gears was VERY helpful to me.

http://www.forum.triumphtr7.com/topic.asp?TOPIC_ID=6672

Rob
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Better to burn out than fade away

[Nightrunner]

My first TR7 was a '76 which someone had transplanted a 5spd into, and kept the 4spd (banjo) rear end. The driveshafts on the 4 and 5 speed cars are different length. This fellow took it to a shop and had it cut to the right length for the swap. It worked OK. I liked the 3.63 ratio with the 5 speed. As you well know its a light duty rear end so no V-6 conversions or Sprint motors. Change the diff oil while you're down there.

Before you install that 5 speed it is well worth your time to pull the rear housing and check the oil pump. If the teeth show any wear, replace them. If this lttle pump fails, the tranny can grenade on you.

Have fun!
Scott

[MickeyR]

[quote]<i>Originally posted by Mowog73</i>

Hi Mickey

We're going for the two cars, 76 with a very good body and the V6 in it and the 77 parts car. We'll be getting rid of the Firebird V6 and putting the proper engine and 4 spd tranny in from the parts car. Definitely want to convert to a 5 spd setup.

We're going to get the parts car this weekend and we may try to start it. The other car won't becoming home until the Spitfire is paint, homefully within a few weeks.

Better to burn out than fade away
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Outstanding! I look forward to hearing more...

Mickey