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Jayro

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Mar 30, 2022
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My Car
73 mustang baby blue with clevo 351
Well I dropped the car in for a dyno run to see if this annoying rattling from the engine could be sorted. They are not sure of the cause but we’re very reluctant to do the dyno due to it. Anyway I convinced them to go ahead with 1 power run and see what we had to work with. Turns out not a great deal, stripe down and fresh rebuild was advised. Bugger


73 351c-22v dyno.jpg
 
Is that a stock 351 C 2V engine? If it is 176 WHP is probably about right.
 
Yeh correct mate. That’s what I’ve got. ah really, I’m being told that I should be seeing at least 220hp on the dyno with 20% extra resulting in about 260-270 at the engine.

Not correct?
 
Jayro said:
Yeh correct mate. That’s what I’ve got. ah really, I’m being told that I should be seeing at least 220hp on the dyno with 20% extra resulting in about 260-270 at the engine.

Not correct?
Click to expand...
1972-74 had 8:1 compression and that tiny 2v carb. I couldn't resist getting new pistons, cam and carb.
 
The 1973 351 Cleveland 2V engine was rated at 164 HP net in the USA, I think you may be in Australia, so not sure what they made there. So, if it is making 176 wheel HP it is stronger than it was when it came out of the factory. Remember that you loose 15 to 20 percent of the engines flywheel horsepower when you go on a wheel dyno. If you had a 4V engine it would probably be a little low, but if it is a 2V then it would be more than fine. If you are making 176 at the wheels then the engine is somewhere in the 220 HP range net, which would be about 265 gross HP. Not sure how HP was measure in Australia in 1973, but here in the USA we went from gross HP to Net HP in 1972. You usually got about a 20% drop in HP just from the change in how they measure the engine output. A 1971 426 Hemi was 425 HP gross and 350 HP net and a stock one would probably put down 280-290 HP on a wheel dyno.
 
Jayro said:
Well I dropped the car in for a dyno run to see if this annoying rattling from the engine could be sorted. They are not sure of the cause but we’re very reluctant to do the dyno due to it. Anyway I convinced them to go ahead with 1 power run and see what we had to work with. Turns out not a great deal, stripe down and fresh rebuild was advised. Bugger


View attachment 64562
Click to expand...
You are right on point with a 2V and torque is adequate for one wheel peels in 1st gear, so your next question is what are your desires in driving the car?

How fast do you want it to go divided by how much cabbage are you willing to drop + how fast do you want to drop the cash = your own personal “rev limiter” 🤷🏻‍♂️
 
DAverkamp said:
You are right on point with a 2V and torque is adequate for one wheel peels in 1st gear, so your next question is what are your desires in driving the car?

How fast do you want it to go divided by how much cabbage are you willing to drop + how fast do you want to drop the cash = your own personal “rev limiter” 🤷🏻‍♂️
Click to expand...

Mate to be honest if I could just get rid of this bloody terrible rattle/flattering noise id be happy to keep it as is for the time being. This whole issue is purely coming about from no one being able to determine the cause of the noise. Seems all the mechanics I go to have the one and only solution "if no idea, rebuild it".

Have a specialised race engine build shop who has agreed to squeeze me in Saturday to give it a quick look over and see if they can pin point the cause of the noise. Driving me crazy. Start great and runs well over all. Certainly running rich though and this bloody noise.
 
Are you talking about detonation/pinging, or a different kind of rattle?
 
This is the problem mate, I’m not 100% what pinging sounds like. I’ve had a couple mention it to me. I’ll try get a video of it in next day or so and see if it’s clear enough for you guys to hear it.

Seems it does it from 2800rpm

Cheers
Jase
 
On the chart, it gets the most torque when in the 13.5-14 AFR range. +- where you hear the noise.
While the values are not that lean to get pinging from the mix alone, it would be fairly easy to enrich a tad and try if it still does the noise.
The pinging from fuel is caused by the mix to ignite too soon or low octane (the noise is the explosion wave hitting the piston while it's still going up) So there too, easy test, remove a few degs of timing and see if it still does it when warm. With 8:1 compression it should accept fairly low octane before do that, may be try 95 or 98 fuel would be another way to remove pinging from your equation... and search for something else if that's not it.
 

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