marks
marks None
Oct. 11, 2011 4:09 p.m.

LOOKING FOR SUGGESTIONS,IDEAS,HELP ON HOT RODDING A 1980 TRIUMPH SPITFIRE. HOW FAR CAN I PUSH THE ENGINE,TRANS,REAR END? WEAK POINTS IN THE DRIVETRAIN? POSSIBLE TO GO TO 5 BOLT HUBS.OR IS IT EVEN NECESSARY ? BESIDES HEADERS ANDWEBERS OR MIKUNI CARBS..WHAT OTHER BOLT ON TYPE MODS WORK? CHANGING ROCKER ARMS? THANKS IN ADVANCE

Dr. Hess SuperDork
Oct. 11, 2011 4:29 p.m.

4 bolt hubs are the least of your worries. Transmission, rear end, U joints and 3 main bearings on the crank are the weak points, in no particular order. And rust. And Lucas electronics. And smog stuff. Besides that, go for it.

93EXCivic SuperDork
Oct. 11, 2011 4:47 p.m.

The differential is the biggest weak point plus the chassis is floppy, they rust like crazy, the rear suspension is a swing axle and can do weird things.

That being said I have one.

It is a '64 that will become a vintage racer.

Oct. 11, 2011 4:51 p.m.

AndreGT6 Dork
Oct. 11, 2011 6:04 p.m.

http://www.gt6.ca/gallery/spit-yellow_ebay/

Ian F SuperDork
Oct. 11, 2011 6:35 p.m.

100 HP seems to be a good number for a Spitfire. While that may not seem like much, it's a light and low car, so it'll get along pretty good with that. The drivetrain bits seem to hold up well there too, as long as you remember the car was never meant for drag racing.

The problem is 100 HP from a Spitfire engine isn't cheap. A less expensive option would likely involve spinning triangles.

marks
marks New Reader
Oct. 20, 2011 3:22 p.m.

that news stand is in laguna beach california by the way....In reply to AndreGT6:

marks
marks New Reader
Oct. 20, 2011 3:25 p.m.

what can be done about the differential? swap it out? i already figured that 100-125 hp was max for the engine the frame can be stiffened a bit i would think would an engine from a gt6 be a relatively easy swap? thanks In reply to Dr. Hess:

marks
marks New Reader
Oct. 20, 2011 3:30 p.m.

what are spinning triangles? headers,new carbs,new rocker arms,cam...some head work....what else should i consider...or am i completely in left field? thanks In reply to Ian F:

93EXCivic SuperDork
Oct. 20, 2011 3:43 p.m.

There are a few companies which offer limited slip differentials. Gripper and Quaife. Spinning triangles refers to a rotary engine. In terms of engines, you could swap to a GT6 but IMHO it isn't worth it. It adds a decent amount of weight to the front of the car and isn't going to be that much easier then swapping to a more modern engine.

TSimported (http://www.tsimportedautomotive.com/), Wishbone Classics (http://www.wbclassics.com/catalog/2), Wolfott Racing (http://www.btinternet.com/~jon.wolfe/wolfitt_products_1.htm) are good sites for performance parts. If you decide to stay with Triumph engines, I would recommend a small crank 1296cc with an early 1500 shaved head.

marks
marks New Reader
Oct. 20, 2011 4:15 p.m.

thanks...what about the stuff sold by a place called PIR or PRI? mikuni carbs,rocker arms...hubs,headers...i know the stuff is expensive but does anyone have an color on the equipment? could i stay with my 1500 spitfire engine or is the 1296cc just a much better starting point? In reply to 93EXCivic:

Ian F SuperDork
Oct. 20, 2011 6:45 p.m.

In reply to marks:

I've seen a few PRI equiped cars. Expensive, but pretty. If you have knowledge of motorcycle carbs, their kits can be duplicated for much less money. A lot of what you're paying for his the time and effort he's put into figuring out what tuning works well.

The most important part of rebuilding a Spit engine is balance. These engines were poorly balanced from the factory and tend to run roughly. Converting the single carb to a Euro dual carb set-up is a popular upgrade as is installing a better exhaust (Bell is my personal favorite). Then you play with cams and other stuff like Euro flat top pistons. Nothing is cheap and easy, though, like with an old V8. You basically have to start with fixing the inherent difficiencies with the engine, then you can work on making power.

A GT6 differential is identical to a Spitfire, but is actually weaker. The frame is essentially the same as well, with most models having additional brackets for the rear lower control arms. The brakes for a GT6 are slightly larger. In general, installing a GT6 engine in a Spitfire (known as a Spit6) creates a fun car, but not a great one. As mentioned, it throws the balance off a bit. I had one. Had. There is an exception... Google: FIS6

Canley Classics is a UK source for Spitfire stuff. They offer a few upgrades that fix some of the problem areas.

There have been conversions to install a Subaru/Datsun rear diff into a Spit, but it requires converting to CV joints and a LCA-type rear suspension as the axles and thus the differential in a Spit is a stressed part of the suspension. A fair amount of fabrication is required. No bolt-in upgrades are available at the time. If it were easy, it would be one by now.

Toyman01 SuperDork
Oct. 20, 2011 7:21 p.m.

These are magic spinning triangles.

Mazda rotary engine out of a RX-7.

They work amazingly well in one of these.

1980 Spitfire.

Since the only thing made by Triumph in the above photo is the sheet metal, I probably can't help much.

Curmudgeon will probably be along before long, and he is pretty good with them. Especially the part where you remove everything made by Triumph and install Mazda bits.

93EXCivic SuperDork
Oct. 21, 2011 7:54 a.m.
marks wrote: thanks...what about the stuff sold by a place called PIR or PRI? mikuni carbs,rocker arms...hubs,headers...i know the stuff is expensive but does anyone have an color on the equipment? could i stay with my 1500 spitfire engine or is the 1296cc just a much better starting point? In reply to 93EXCivic:

I don't really know about PRI but I wouldn't spend my money on their rear suspension. It's geometry doesn't really impress me. The 1500 can be a decent torquey street motor but they don't like to rev. They were two 1296s made. The small crank and large crank. The small crank is much preferable but my car is going to run an early 1500 (the early 1500s have the largest valves).

marks
marks New Reader
Dec. 16, 2011 1:09 p.m.

ok...so basically i should focus on making the car as light as possible...addressing the weaker areas and be happy with about 95 hp in a 1600 lb car..... or can i just upgrade carbs,exhaust,rockers for the suspension...spax shocks or coilovers? heavier sway bars? how could i upgrade to 5 bolt hubs? or should i? differential and trans should be able to handle 85-95 hp if they are in good shape? thanks again.... this is a slow moving project...fyi

noddaz Reader
Dec. 16, 2011 2:10 p.m.

Might be reverse engineering (or maybe a quirk of fate?), but possibly find an old Miata that runs as a donor...

driver109x HalfDork
Dec. 16, 2011 3:02 p.m.
marks wrote: that news stand is in laguna beach california by the way....In reply to AndreGT6:

Nope the address says its in Woodland Hills CA...

aeronca65t Dork
Dec. 16, 2011 4:57 p.m.

I raced an MG Midget with a 1500 BL engine (same engine as Spitfire) for 7 years. I changed rod bearings every 25 hours and kept RPMs under 6000. As a result I got roughly 200 hours of racing out of that (mostly stock) engine. You also need to watch the thrust washers in all Spitfire engines.
Everyone says the 1500 is crap. While I prefer the 1296 (in a Spit), the 1500 can be decent if you work within its limits. Mine made maybe 80 HP and was great fun. I blew one trans (also same as Spit) in 7 years. The newer single rail unit is better but the shift linkage isn't great in any of them.

Here's the view aboard my 1500 Midget

I like the regular fours in these cars: I think they suit them better than a high powered engine swap. But that's just me. There are guys that put the Subaru rear diff (or the similar diff from older Nissans) in Spitfires. But most of the rear end failures I see in these cars are from old u-joints (or flex couplers). I know you didn't say this, but If you want to do some sort of V6 or V8 swap, you might be better off with a live axle MGB.

Ian F SuperDork
Dec. 16, 2011 5:23 p.m.
marks wrote: ok...so basically i should focus on making the car as light as possible...addressing the weaker areas and be happy with about 95 hp in a 1600 lb car..... IMHO, Yes or can i just upgrade carbs,exhaust,rockers It's a good place to start, about in that order for the suspension...spax shocks or coilovers? heavier sway bars? Yes, coilovers mainly add the ability to fine tune ride height and spring stiffness, but regular Spax shocks and sport springs will work well enough for a driver. A larger front sway bar can be a catch-22. Stiffening does help, but the mounting points on the lower A arms should be reinforced. Rear upgrades are debatable. Personally, I would rather not install something that will limit wheel movement. how could i upgrade to 5 bolt hubs? or should i? No reason to. If anything, the upgrade is to a 4x100 blt pattern so wheels are a bit easier to find. There are bolt-on adapters or PRI sells a conversion kit ($$$$). differential and trans should be able to handle 85-95 hp if they are in good shape? Yes thanks again.... this is a slow moving project...fyi I know the feeling... most of my projects move slowly as well...

Answers in italics above.

erohslc HalfDork
Dec. 16, 2011 6:06 p.m.

differential and trans should be able to handle 85-95 hp if they are in good shape? NO! They cannot even handle even stock power levels

Here, I fixed that for ya'

(Owned and raced Spitfires since 1968, still have 6 of them)

Carter

93EXCivic SuperDork
Dec. 16, 2011 7:28 p.m.
erohslc wrote: differential and trans should be able to handle 85-95 hp if they are in good shape? NO! They cannot even handle even stock power levels

Really the transmission?

aeronca65t Dork
Dec. 16, 2011 7:37 p.m.

I got about 150 hours (racing, wheel to wheel) out of my first, stock, single rail trans. I bought another for $200 and with about 50 hours of racing, it's still fine.
I prefer the "ribcage" trans (and 1275 engine) that I swapped in last year, but I never thought the Spit trans was that bad.

And I forgot to mention: the "Euro carb" setup (with twin 1-1/2 SU carbs) is a nice, cheap improvement. You can find them on EBay UK or some of the Canadian parts sites.

marks
marks New Reader
Dec. 22, 2011 10:25 a.m.

In reply to aeronca65t: what modifications does your 1500 cc engine have? thanks

ArthurDent Reader
Dec. 22, 2011 11:46 a.m.
aeronca65t wrote: I got about 150 hours (racing, wheel to wheel) out of my first, stock, single rail trans. I bought another for $200 and with about 50 hours of racing, it's still fine. I prefer the "ribcage" trans (and 1275 engine) that I swapped in last year, but I never thought the Spit trans was that bad. And I forgot to mention: the "Euro carb" setup (with twin 1-1/2 SU carbs) is a nice, cheap improvement. You can find them on EBay UK or some of the Canadian parts sites.

I dunno about Canada - my '74 had the same ZS carb as the US version.

aeronca65t Dork
Dec. 22, 2011 11:59 a.m.
marks wrote: In reply to aeronca65t: what modifications does your 1500 cc engine have? thanks

Nearly stock. Lightened flywheel, 9.5:1 pistons, cheesey Pacesetter header and Kent "fast road" cam. Not balanced. Stock crank and rods. Standard vavle gear. The main thing with the 1500 is to keep the RPMs at a moderate level. I virtually never went above 6000 RPM and generally shifted at about 5700.

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