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Gutless Sprite.

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Jedi Warrior
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I need a little help diagnosing a problem with a Sprite. I drove our recently restored Mark One on a Austin- Healey club tour today. On the flat the car performed OK considering its 948cc engine. But faced with a hill the car just died. On a 15% incline I had to go down to first to climb the hill! Later on, after staying with our friends on gentle undulating country we came to a long uphill gradient (nowhere near the previous 15%). Down to third, then second before we stopped losing speed. The engine is out of a Morris Minor and came with HS2 carbs and exhaust extractors. It was tuned using Colourtune. Starts OK with a lot of choke, and takes some time to settle without the choke in our warm Queensland climate. Compression checks out OK. Oil pressure and water temp good and no blue smoke from the exhaust. Any suggestions gratefully accepted.
I should add that my normal drive is a 100 BN1 and I expect a lack of torque when in the Sprite. But this sheer lack of ability on a hill can't be normal.
Cheers.
 
Not sure about the Morris piece, but, maybe timing?
 
Thanks Rick, perhaps I should have added that prior to the rebuild the car had a Morris Minor engine and I recall it did not have this performance problem. I have to admit that I don't know the exact spec of the current engine. I bought it off a Minor owner who was swapping it out for a Japanese engine.
 
IS the Heat Shield in Place under the carbs?
 
When it's sputtering how about the exhaust then? And does this sputtering let up when you're off gas?
 
If it were mine I would try a flat richer on the crabs and see if that makes a difference. Also wonder if the fuel pump is keeping up on the grades. Fuel cap vented?? Timing OK??

Kurt
 
if its loosing power up hill and carbs are balanced and adjusted right I suggest a compression test, and yes the minor and spridget have different cam & head
 
All this is the symptom of the dreaded recessed blanking plug in the head (that spans cylinders 2 and 3). Only when under load will the gases blow through the firing rings.
Obviously, try everything else first before pulling the head.
 
Easy for me to sit here and say: go through the tune-up per manual so as to eliminate issues. Stuff like valve clearances, spark plug gap and condition; static and dynamic timing and dwell, spark plug wire resistance; fuel filter condition etc. etc. etc. Dunno if you have a way of checking your vacuum as my recollection is that vacuum goes down under load and affects the advance on the distributor; we're not running SUs on our 948 but I've seen suggestions that the needles should be updated to match current fuel mixes; do a leak down test to look for surprises. I'd offer to help, but I'm completely out of Magic Pixie Dust to sprinkle over everything. Doug (PS: an old rule of thumb was that dividing total vehicle weight by hp and then dividing by 2 should give you an approximation of your 0-60 mph time. Try checking that time as it will give you a rough estimate of the hp that you've got and maybe provide a baseline bit of information.
 
Thanks for the input everybody. In reply to Boink, the engine doesn't "sputter", it just wouldn't pull. I'm thinking fuel so the suggestion of checking the needles is a place to start.
 
+1 to do a compression test. My '69 Sprite with a 1275 was exhibiting similar symptoms, it felt like "The Little Engine that Could" any time I pointed it uphill, it just had no oomph. It turned out my head gasket was heading south, but the leaking wasn't bad enough that I was seeing any smoke. The compression test showed that Cylinders 2 & 3 had dropped to 90 psi, down from around 150. I stopped driving the car and pulled the head. Sure enough, the head gasket was toast, and there was a nice little pool of coolant sitting atop one of the pistons.

There could be a bunch of other reasons you are losing compression other than the head gasket, but compression would be where I'd look first.
 
No, they are the same. There are 3 different part numbers, but they are grouped together as standard use cams for 850 Mini, & all 803 & 948CC engines. They are part numbers 8G 712, 2A 297 and 2A571. They are grouped in Vizard's book, all having the same specifications. The heads are also the same , most commonly the 2A 629, also listed for 803 Austin/Morris, 850 Mini, 948 Morris Minor, A35 Austin A40 Austin, Sprite MKI. Again, these are all "Group A" with the same specifications in Vizard's book. What is different between the Austin and Morris is use of a Single carb in the morris and dual carbs in the Sprite, as well as different gearbox ratios. Difficulty climbing a steep grade really isn't to surprising given the low HP and torque of the 948. You'd need to have everything (carb sync, timing, compression, etc.) dialed in perfectly for it to perform moderately better. A Colortune only helps with mixture; your timing or needles could be wrong (you don't say what elevation). Both with have a significant effect on performance. However, a 15% grade is extremely steep, so I think the expectation is to high for a 948. I wouldn't expect to climb that steep a grade in anything but first. I live in San Francisco, and even less steep hills can be a challenge.

HealeyRick said:
Doesn't the Morris motor have a different cam and head than the Sprite? It could be you just don't have very much power in that car.
Click to expand...
 
Gerard, I think I have been on some 15% grade hills in San Fran. Maybe more. Stationed there in the Navy.
 
Thanks Gerard, I have always thought that the only difference between the Sprite engine and the Minor is that Sprites have camshaft bearings, whereas the Minor cam runs in the block.
I tried two flats on the carbs and found a slight improvement. If two is good, will more be better?
Sea level, by the way but only a little higher in the hills. I know not to expect much from a 948, but having to use first was a disappointment.
Cheers,
Alwyn
 
I had similar problems and found that the points had slipped and were barely opening. Resetting them solved the issue.
 
We've had our 948 cc Sprite running off and on since 1973 and although not particularly powerful, it's always been adequate for normal city and highway usage - top speed (if memory serves) was into the low 80s on a flat surface. Doug
 
Mine wouldn't pull or rev worth a darn, found the vacuum advance had failed. Easy and cheap fix. Worth checking out.
 
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