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Professional troubleshooting for my 1098??

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What I'm hearing sounds pretty good if this is a stock set-up. The only bogging down I heard was once on the missed down shift and a couple times when there should have been a downshift but wasn't. The time you mentioned when you shifted from third to fourth you really didn't wind it up much...

What rear end are you running?

Ray
 
The rear end is stock, so 4.22 or whatever was in the '66.

Obviously something that limits my interstate ability :wink:

The main difference to me is the way the car breathes at the top end. My other sprite seemed to not mind living life north of 6k rpm. This one has a plateau of power delivery and almost feels like it's telling me to stop, because I'm hurting it.
 
What timing are you showing, a) at idle (no vacuum) and b) full advance? Sounds like a timing issue to me, particularly if you've got squeeze and spark, and it's not perking up at the top of the rev range...
 
If your other engine liked 6K it had a cam in it. Stock engines run out of oomph about 5500.
 
Luke_Healey said:
OH, yeah, there are a couple of springs in the distibutor for mechanical advance. I assume I perform that test with the vacuum advance unhooked?
Click to expand...

Yes. I am not sure what total advance (initial + mechanical) should be. I need to look that up. It helps to have a dial-back timing light since there are no graduated timing marks on these critters, but it should at least move as RPMs increase.
 
Not really more rpm.

948 is rated at 5500

1275s may be a bit more but none are rated at over 6K Stock. In fact I would expect valve float to start about there as well.

What did change was torque which went up with each improvement but it was rated at 3300 rpm.
 
<span style="color: #FF0000">UPDATE </span>

OK, this is pretty stupid, but it did improve the car's performance. Perhaps almost to the level of my other Sprite.

Tonight I was dinking around in the garage and was moving my donor carb setup and realized it had the original fuel line installed. My Sprite had some junky clear fuel line installed and it was never meant to bend 90 degrees twice. Though it didn't look pinched off to me, and I could see air bubbles move through it as the car runs, I figured what the heck. If nothing else it'd look better to swap out the original fuel line since it was still pliable and all that.

The crap I removed:
2659620513_f8f606dc15.jpg


The new setup:
2660449014_6050714bb0.jpg



The result? The car seems to rev more freely. I was running 75mph down the road without issue other than the engine was protesting. I would benefit greatly from an overdrive in the transmission.

It made a noticible difference. I'm sure this isn't the end of the road, but I imagine the rear carb would starve for fuel when I was pushing my foot through the floorboard for long enough. I haven't verified 100%, so I should make another video and a run up to the proving grounds.


I did not get around to testing mechanical advance. I hooked tubing to the vac advance and it is in working order and doesn't leak air. I'll have to test the mechanical advance this weekend.

The car is still running hot, so I need to deal with that. I bought some of Prestone's coolant system cleaner and plan on running it through the car for a while.

I also now have a fairly major oil leak, but I think I found it and sealed it. The oil pressure gauge tubing connection was leaking at the block and I tightened the fitting. So far, a LOT of bolts have been way too loose on this car. Whoever put it together was being overly cautious with torque. I found my brass nuts on the exhaust clamp FINGER tight last night.

Anyway, I wanted to check in. The car is probably running better than most. But I still feel like there's an caged animal waiting to be released.
 
Well, this is progress, no matter how small it may seem. Congrats!
Keep posting as you do other tests.
 
Super, glad you are finding your way through these many problems.
 
I forgot to add this yesterday:

I was mistaken when I said fuel pressure was 4psi.

This is what I measured yesterday:

2663014216_a4cce838fa.jpg




So that looks good. I'm not sure what happens when the pump is under demand. I think it's able to keep up.
 
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