tr8 conversion

pupinabox · Postby **pupinabox** » 30 Sep 2008 00:12

I have been kicking around the idea of doing the tr8 conversion on my 81 DHC.

Two questions. Do you have to do anything with the transmission or is the stock 5 speed okay. Second, is there a book or web site somewhere that goes over this step by step so I can see what I may or may not be getting into?

tr7sprint1 · Postby **tr7sprint1** » 30 Sep 2008 02:08

Go to this link: http://www.triumph-cars.co.uk/

Then go to page eight of the magazine articles section, you will find three articles on the v8 conversion. Their many other articles on the v8 conversion and other interesting items to read on this site.

"GETTING SPEED OUT OF A LOW POWERED CAR IS OFTEN MORE REWARDING, THAN WITH TIRE-SMOKING BRUTES"

FI Spyder · Postby **FI Spyder** » 30 Sep 2008 02:35

Stock 5 speed is the same, bellhousing is different. Diff is 3:08 not 3:90 so you would need one of that as well. Since it would be a TR7/V8 and not a TR8 it's value would not be as high (theoretically). Since your in the USA you might consider a Buick V6 conversion.

Advantages: lower cost as you can get a whole car for $500 for the transmission/engine etc, easier to get than alloy V8.
- More horsepower, 50% more for stock engines.
- Use Buick Transmission.
- Easier drop in with John's Cars kit.
- Easier to get parts in USA.
- Here again if you can get a 3:08 diff. 1st gear will become usable.
- The Buick V6 (not Chev) is only 35 lbs. heavier so you can keep TR7 steering. V6 shifts weight the rear so better balance.

TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

Bill · Postby **Bill** » 30 Sep 2008 17:59

Check out this article, written by a member of our club, it outlines the process complete with part numbers. http://www.detroittriumph.org/Review/FindaCleanTR8.htm

Bill
1980 Persian Aqua DHC

Underdog · Postby **Underdog** » 30 Sep 2008 18:10

An 81 should have a 3.45 rear so the gear change may not be needed depending on what you want. I switched out the 3.08 in my TR8 for the late TR7 3.45. Better aceleration at the expence of higher revs at cruise. Also the last 5spds had a taller 5th gear to overcome the lower rear gear at cruise. Mine has the normal 5th gear and does 73mph at 3000rpm.

I can see the point on the V6 option. Would depend on what you have to pay for a Rover V8. Last I heard, the bellhousings were around 250 -300. TSI sells a crossmember modified for the V8. Woody at The Wedge Shop can tell you everything needed for a swap.

Whichever you decide, the car will not be a TR8. Nothing wrong with building a clone though. The Muscle car guys do it all the time. Just don't sell it as a TR8 unless you want to risk ending up in court. Long story but I saw it happen first hand. Not trying to sound snooty and maybe you already know this.

Third option would be to sell your 7 and just buy an 8. Prices are surpisingly low. Someone just pointed out that there are 5 of them on ebay right now.

Jim

72 MGB BRG
80 TR8 Persian Aqua
If women don't find you handsome, they should at least find you handy.

Yoke · Postby **Yoke** » 30 Sep 2008 21:16

I don't mean to jump the thread but I need someone to answer a question for me.... on the TR8 is the rad located in the same spot as in the TR7 or is it pushed back into the nose. I'm to the point where I need to hook up my rad and give her(the engine) a good run. Needless to say I'm getting a little frustrated in trying to mount up the rad. Pictures, opinions would help a lot.

Can't save them all but I am trying!!!

john 215 · Postby **john 215** » 30 Sep 2008 21:41

Hi,
The TR8 rad is indeed further forward, a couple of inches and has different top and bottom mounting brackets. the holes for the upper location are the same just the brackets are a different shape. The lower mounting bolt holes should already be in your chassis rails.If no one has put any pictures by tommorrow eve will put some on for you.
As for books try this, not exactly a step by step guide but a good reference source-
http://www.amazon.co.uk/How-Improve-Tri ... 528&sr=8-2

As for gearbox stock 5 speed good for most applications, just req a bell housing of an SD1 or similar and a cluch fulcrum bolt for the release arm
Cheers John

LIVE LIFE A QUARTER OF A MILE AT A TIME!
1979 3.5 FHC(STATUS PENDING!!)

1982 2.0 DHC NOW A 4.6 WILL BE ON THE ROAD VERY SOON!
Read My Blog http://www.waringstowntr7s.co.uk/blogs/ ... hp/John215

FI Spyder · Postby **FI Spyder** » 30 Sep 2008 22:20

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Underdog

An 81 should have a 3.45 rear so the gear change may not be needed depending on what you want. I switched out the 3.08 in my TR8 for the late TR7 3.45. Better aceleration at the expence of higher revs at cruise. Also the last 5spds had a taller 5th gear to overcome the lower rear gear at cruise. Mine has the normal 5th gear and does 73mph at 3000rpm.

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

A friend has a V6 with 3.45 and he never uses first gear. Said he really needs 3.08 to make 1st worth while. He has a T5 transmission (5th gear is overdrive), I don't know what final drive is but he has 235 HP to play with.

TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

pupinabox · Postby **pupinabox** » 30 Sep 2008 23:23

Thanks for the info guys. my 7 is basically in showroom shape and I don't want to get rid of it for an 8 because I have done so much work to the cosmetics and such (kind of attached to it now).

I still have a few bits to tinker with, I just thought some type of engine conversion might make her last longer and with less potential hassles.

I will give these sources a look. I live about an hour away from TSI and have to pass close to it all the time to pick up my kid at college. The in-laws live about an hour from Woody's, Maybe this is some sort of a sign......[:p]

I just wanted to get an idea of what I might be getting into, as my mechanical knowledge "has massive upside potential" shall we say.

silverseven · Postby **silverseven** » 01 Oct 2008 02:05

-for the record, has anybody ever contacted Woody for on what a regular "turn-key" conversion of a clean wedge would cost?????

Oddly enough, for the past little bit I too have been pondering a v8 conversion on my car, possibly in the next couple of years.....

Ron.

Underdog · Postby **Underdog** » 01 Oct 2008 13:26

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by FI Spyder

[quote]Originally posted by Underdog

An 81 should have a 3.45 rear so the gear change may not be needed depending on what you want. I switched out the 3.08 in my TR8 for the late TR7 3.45. Better aceleration at the expence of higher revs at cruise. Also the last 5spds had a taller 5th gear to overcome the lower rear gear at cruise. Mine has the normal 5th gear and does 73mph at 3000rpm.

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

A friend has a V6 with 3.45 and he never uses first gear. Said he really needs 3.08 to make 1st worth while. He has a T5 transmission (5th gear is overdrive), I don't know what final drive is but he has 235 HP to play with.

TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

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

Like I said, depends on what you want with the gear ratio. When I first installed the 3.45 it was with the stock engine/Holley/headers combo. It did drop the ET at the drag strip. Yes, I can start in 2nd gear too but don't do it on a regular basis. I like the improvement in acelleration but that's just me. For better cruising, I agree, the 3.08 would go back in but not my plan for now.

72 MGB BRG
80 TR8 Persian Aqua
If women don't find you handsome, they should at least find you handy.

Anonymous

tr8 conversion

tr8 conversion

Who is online