Dyno Day!

Lowtechprime

Lowtechprime

Retro Grouch
Had the 1500 test motor Dyno set-up today! Pretty happy with the results! Ended up with 78hp at the wheels, 90hp at the flywheel... About 13.3hp in drive line losses... Just a 1500 block, super mildly skimmed 1300 head with 10000 rpm springs, 231 cam, 34 DMTR, and 4-2-1 header.... I'm building the 2.0 litre, 10000 rpm motor, but didn't think that should be my first Fiat SOHC that I put together, so I built this 1500 first.....
 

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Lowtechprime said:
Had the 1500 test motor Dyno set-up today! Pretty happy with the results! Ended up with 78hp at the wheels, 90hp at the flywheel... About 13.3hp in drive line losses... Just a 1500 block, super mildly skimmed 1300 head with 10000 rpm springs, 231 cam, 34 DMTR, and 4-2-1 header.... I'm building the 2.0 litre, 10000 rpm motor, but didn't think that should be my first Fiat SOHC that I put together, so I built this 1500 first.....
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Your'e gonna have a blast driving this around. Even with just 90 HP!
 
Good job and great looking engine!
How are you getting to 2L?
Stilo crank and 89mm pistons?
 
Well.... Now it's bad news..😠 This car's been running for weeks in the driveway, I drove it about 100 miles on Dyno day to and from, all fine. Now I went out to move it so the wife could get out, and it won't start at all. I mean it doesn't even sound like it wants to, it just spins like there's no plugs or fuel... I checked spark at the coil, fine. Checked at the plugs, fine.. Gotta check gas next and I'll check compression, but I have to work now.. It'll have to be later....🤬 Was hoping to go to French/Italian car show this weekend...
 
Lowtechprime said:
Well.... Now it's bad news..😠 This car's been running for weeks in the driveway, I drove it about 100 miles on Dyno day to and from, all fine. Now I went out to move it so the wife could get out, and it won't start at all. I mean it doesn't even sound like it wants to, it just spins like there's no plugs or fuel... I checked spark at the coil, fine. Checked at the plugs, fine.. Gotta check gas next and I'll check compression, but I have to work now.. It'll have to be later....🤬 Was hoping to go to French/Italian car show this weekend...
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Ooh, not good. When this happened to me many years ago, the crank had spun the teeth off the timing belt. The engine turned over faster than normal and wouldn't fire at all. After poking around like you have, I went to check timing and noticed that as I bumped the car in gear to turn the engine over the cam gear clearly wasn't turning. My heart sank.

I hope that's not your problem...
 
Thanks for the suggestions but, It's been running fine for weeks now, and was on the Dyno at 7000 rpm... I think if the belt were the wrong length or tension it would have been a problem before now..
 
Starting probably puts higher stress on the timing belt than revving at 7K. Easy enough to check for a bad belt.
 
My SCCA H production 1500 had 101 ground pounding HP at the rear wheels. 10.9:1 compression, .450" lift cam and single prodified Weber 32 DMTR carburetor.
 

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So... Update. (Somehow) My cam timing was off by 4 teeth, and the distributor was out 190°!!??? No wonder it would not run. The real question is how could that possibly have happened!?? It had been running for weeks in the driveway, then I drove around the neighborhood for a few days to fine tune the jetting so it would be safe to drive the 45 miles down to the Dyno, then drove down to the Dyno, had the tuning session, then drove 45 miles home. Ran like a dream the entire time, idled around 900, sounded great at all throttle positions and a/f ratio hovered in the mid 14's. Got home, parked it, next morning it was like this? Upon inspection, nothing was loose, broken, or missing. The distributor had not moved, the belt was tensioned. Somehow, trying to start that morning had to have jacked up the timing, I just don't see though how that's mechanically possible....?
 
Lowtechprime said:
So... Update. (Somehow) My cam timing was off by 4 teeth, and the distributor was out 190°!!??? No wonder it would not run. The real question is how could that possibly have happened!?? It had been running for weeks in the driveway, then I drove around the neighborhood for a few days to fine tune the jetting so it would be safe to drive the 45 miles down to the Dyno, then drove down to the Dyno, had the tuning session, then drove 45 miles home. Ran like a dream the entire time, idled around 900, sounded great at all throttle positions and a/f ratio hovered in the mid 14's. Got home, parked it, next morning it was like this? Upon inspection, nothing was loose, broken, or missing. The distributor had not moved, the belt was tensioned. Somehow, trying to start that morning had to have jacked up the timing, I just don't see though how that's mechanically possible....?
Click to expand...
Man, I think you dodged a bullet. I'd toss that timing belt in the trash, get a new one. Double check that your pulleys don't have worn teeth.
 
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