• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

performance upgrades

Share this page

Atrus

Atrus

Jedi Warrior
Offline
Hey all,

I'm daydreaming while wasting time before my MBA class, and my thoughts turned to the '68 Sprite sitting in my garage under it's winter cover. I did a cheap "spray-bomb" restoration on it a few years ago, it sat for 3 years while I was in undergrad, and I finally got it out on the road this past summer. I plan on driving it as-is for summer '07, and then beginning a much more thorough restoration/customization project in spring '08. Stuff like custom seat covers, stereo, shaving door handles, etc.

I'd like to do a few driveline upgrades. I'd definitely like to get a little more pep out of the engine (not sure how many miles are on it or anything), and I'd like to get a 5 speed in there. I see going two ways - datsun conversion/1275 upgrades, or going crazy and fitting a GM 2.8 60* V6 and a T-5.

I want the car to be a cruiser - driveable and fairly reliable. I don't want it to be really finiky. So...

1) What upgrades would you recommend for the 1275? What will said upgrades net me, power-wise? Do these cars respond well to porting/polishing/increased compression? Cam? intake/exhaust upgrades?

2) Seals - I really would like to have a non-dripping car. Right now, mine leaks fairly badly. It could be oil pan, could be a front or rear main. I know LBC's notoriously drip. Is there a good fix? I also read here that some people have had major leakage issues after the Rivergate conversion. That's something I definitely have no interest in dealing with (leaking oil), so that's one of the major temptations to a swap for me.

3) Pertronix ignition - how reliable? For the $80, it seems worthwhile to me as I am 25 and I hate points. I grew up in the age of electronic ignitions and fuel injection. This is actually my first carb'd car.

4) Along the lines of the pertronix, is there some type of EFI system for these cars? I figure not, and if so it's pricy, but I figured I'd ask.


If you can, please just list out what engine mods you'd recommend and where they should theoretically put me. I'm not planning on doing a $5,000 engine rebuild by any means. Just looking to upgrade a bit. For example, I've done some suspension/computer/intake/exhaust upgrades on my '99 Grand Prix daily driver. Over 120,000 miles and it's still really reliable. My point is, I don't want to be blowing pistons or having to rebuild often.

Thanks!
 
I think your choices are very much dependent on how much you can spend and how much of the work you can do your self?

Sky is the limit, otherwise a rebuild may be the way to go.
 
This quetion is often discussed on the forum. but here we go again and everybody has an opinion. With a 68 you probably have a 1275, so that is good. Check the engine serial #s (should start with a 12). If no no., look under the carbs, and if you don't see 2 plates, you have a 1275. The electronic ign. is a great place to start, and while you are going there, get a sport coil (a lot more volts, hotter ign.) and that problem is gone. If you drive the highways (70mph) the datsun 5 speed is a nice conversion, but it is getting hard to find the trannies, and I suppose the cost is going up. If you can find one in an old salvage yard, $150, if bought outright, $450 and up. I'm guessing the kit at $750. It is a really nice and well engeneered way to go. I don't think your car has a 3.9 rear diff, if your car has a 4.22, that by itself gets you a little faster for the same revs. Rebuilding the motor will slow the oil leakage, deppending on how good a mechanic you are. A couple yrs. ago, a tractor ttrailer full of s2000s wrecked in the area, and there were drive trains available. If I new how much I will spend in the direction I now going, I would have researched that a litle more.
 
Thanks for the replies. I would plan on doing the vast majority of the work myself. I am fairly experienced with engine work, although I can say I've never done anything with the lower end of an engine. My uncle is extremely knowledagable (although, he's a muscle-car GM guy), and used to have a cylinder head shop. So, short of performing actual machine work I can do it or have access to someone who can handle whatever is thrown at him.

I do, indeed, have the 1275, and if I remember correctly I have the 4.22 rear.

I guess what I am really curious to is what is a cam/headwork going to do for me? I can't see headers or intake work providing big gains. What's typically done on a 1275? Can the compression be reliably bumped up?

If I can get a trans conversion for $1,000 and upgrade the engine for $1,000-$1,500, I'd say the ease of not having to fabricate so much is worth it to me. On the other hand, if we're looking at $3k+ in drivetrain upgrades, I could essentially get a 2.8/T5 and spend a lot of time and save myself a good $1500 min. I'd guesstimate it'd run me about $1000-$1500 for the V6 swap, but of course, the amount of time and work would be exponentially harder. I'm not really stuck on keeping the car stock at all, however, I am all about the best balance of the lower-cost and easist option.
 
Better fuel delivery, either a Weber side draft or EFI which is almost available from Austin Healey Spares, they are still doing some tests before it hits the market as a bolt on unit.
I guess if you have to ask how much it costs, you'll do the Weber conversion instead /ubbthreads/images/graemlins/wink.gif
Also, rim flow valves are NOT worth it. BTDT and saw no noticable improvement. Now an aluminum flywheel made a big improvment for the same money as rim flows.
Petronix is OK, I fried 3 of them so if you go that way, carry points with you. As for a hot coil, just tape a $20 to a stock coil and you will get the same results. It takes X to fire a plug, if you have 5X, 4 of them are wasted.
I have tried the Sport coil, stock coil, and a basic Bosch blue coil is more reliable than any Lucas coil over decades.
As for a GM v6, it will make a nice straight line rocket out of a nice twisty road sports car.
 
Weight of complete 1275: 253 lbs
Gearbox weight: 46 lbs

2.8l Chevy, without flywheel or clutch: 350 lbs
T-5 tranny: 78 lbs

Lotsa extra poundage up front, Kevin.
Jeff
 
The proper head and head work will give you an additional 10HP.
 
Good point on the weight. I've got plenty of time, looks like I have a lot of thinking/planning to do. I honestly can say I don't use the car for the twisties. I also can say I don't use it for drag racing. I'm really looking to speed it up a little and make it more streetable to cruise in. Obviously, hitting the pedal and watching the speedo climb is always fun /ubbthreads/images/graemlins/wink.gif

What fries the pertronix? That makes me a little nervous as well. It's that easy to swap it right back to the old points in a pinch? By "fry" do you mean, the car just completely dies, or does it just not run correctly, but it can be limped back home?
 
The best $40 you can spend is to go to amazon and buy David Vizards book. They are available used and you should buy the newest version available. This will give you an idea of what works and what doesn't. Although there are always differences of opinion, Vizard is widely known as one of THE experts.
You might want to just do a stock rebuild and bolt on a belt driven supercharger, Moss and Mini-Mania both offer kits. A 5-speed will be necessary to get the revs down on the highway, no fun buzzing along at 4200 RPM all the time.
 
[ QUOTE ]
The best $40 you can spend is to go to amazon and buy David Vizards book.

[/ QUOTE ]

"Tuning the A-series engine" Should be able to get that + an SU book for $50.
And I agree, it is a useful book and it keeps giving.
 
Paid $20 bucks for mine and it wound up being a signed copy.
 
" What fries the pertronix?"

2 bit guts? I don't know for sure but if someone gives me one, I'll throw it out. electronis bolt to where the points and cond were in a stock dizzy. Just save your old points and cond to screw back in WHEN the electronics die. And they just stop working on a rainy day on a high speed freeway or when you daughter is 100 miles from home.
 
Thanks guys, I'll look into picking up a copy of that book.


Hmmm...have to rethink this ignition thing then too...
 
Always good to take some time to think these things through. I'll add to the recommendations for the Vizard book--it's a good place to get an idea of what is possible with a 1275. Lots of folks here have years of experience building these motors, so you'll get good thoughts from this bunch as well.

The 1275 takes to modifications pretty well, and there is a good aftermarket for go-faster bits. Spridgets are pretty light, so don't need all that much power to feel snappy. Stock motor made somewhere around 60hp depending on year, and I've read that 80hp isn't too hard to get out and still be streetable. That's not bad for a light car like these.
 
And all out 130HP is possible.
 
[ QUOTE ]
Always good to take some time to think these things through. I'll add to the recommendations for the Vizard book--it's a good place to get an idea of what is possible with a 1275. Lots of folks here have years of experience building these motors, so you'll get good thoughts from this bunch as well.

The 1275 takes to modifications pretty well, and there is a good aftermarket for go-faster bits. Spridgets are pretty light, so don't need all that much power to feel snappy. Stock motor made somewhere around 60hp depending on year, and I've read that 80hp isn't too hard to get out and still be streetable. That's not bad for a light car like these.

[/ QUOTE ]

80 hp and a 5 speed would be just fine by me. I know they were 60-65 new, and I am sure mine isn't running anywhere near that as it's still not tuned properly. 130 would be great, but I am sure that's pricy and reliability goes down the tubes.

Thanks guys! First thing I'll do then is get that book.
 
80 hp and a 5 speed would be just fine by me. I know they were 60-65 new, and I am sure mine isn't running anywhere near that as it's still not tuned properly. 130 would be great, but I am sure that's pricy and reliability goes down the tubes.


Yep... Can get kinda pricy... but sure is fun... BTW... So far I have not had any problems with reliability...

• 1275 Bored .030" oversize
• 3 Ring, High Compression Pistons
• Compression Ratio 10.5:1
• Aluminum 11 stud Cylinder Head, Stellite valve seats
• Roller Rockers - 1.5 Ratio
• Bronze valve guides
• Rim flow valves
• Maniflow Steel intake manifold (chromed)
• Dual HS4’s
• Balanced all Rotating & Reciprocating Parts
• Lightened flywheel
• Scatter Pattern Camshaft SPVP4
• Crane XR700 ignition
• Pertronix Second Strike box with rev limiter
• Ceramic coated LBC header
• ARP Fasteners
• Gear Reduction starter

PC070044.jpg


Had some fun with the suspension and threw in the Rivergate 5 speed also... zoom zoom... /ubbthreads/images/graemlins/driving.gif
 
Theres that engine and engine room to die for again. You got to stop doing that to us, it's criminal.
 
Thats a nice looking engine bay, yep I say you got it bad too /ubbthreads/images/graemlins/smile.gif
 
justaguy, can you give me details on what looks like a fancy catch bottle (right of the radiator, has hoses running in, air filter on top). Thanks!
 
Back
Top