RPM
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From: Porterfield
RPM
>It depends on condition, On an old tired 400 I wouldn't go
>over 3500. On a rebuild it depends on how it was set up,
>4500-5500. Ask Shazam how far one will go if it is built
>right :-)
>
bone Stock 400 4200 Rpm's
with a little twiking 5800 Rpm's
with a lot of twiking 8500 Rpm's
to date my 435's highest rpm Run 8300 Rpm's lasted 24 Sec.
to date on my 426 Highest Rpm run was 8800 Rpm's lasted 28 Sec.
Both motors are still running strong.
ShaZam
>over 3500. On a rebuild it depends on how it was set up,
>4500-5500. Ask Shazam how far one will go if it is built
>right :-)
>
bone Stock 400 4200 Rpm's
with a little twiking 5800 Rpm's
with a lot of twiking 8500 Rpm's
to date my 435's highest rpm Run 8300 Rpm's lasted 24 Sec.
to date on my 426 Highest Rpm run was 8800 Rpm's lasted 28 Sec.
Both motors are still running strong.
ShaZam
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Joined: Aug 2000
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From: (near) Denver USA
RPM
I routinely (every day) push my beat old, 188K mile, bone-stock 351M past 4K rpm, occasionally past 4.5K rpm, and I've had it over 5K a few times. That's with a tweaked Motorcraft 2150 2V carb, not the stock unit, but it's on the stock intake manifold, with stock exhaust manifolds.
With a stock 2V carb, the engine wheezes out of breath by 4K rpm, obviously well below its mechanical capacity.
I know of people who push stock 400s with 4V carbs to 6K rpm occasionally. Some of them haven't blown up yet.
With a stock 2V carb, the engine wheezes out of breath by 4K rpm, obviously well below its mechanical capacity.
I know of people who push stock 400s with 4V carbs to 6K rpm occasionally. Some of them haven't blown up yet.
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Posting Legend
Joined: Sep 2001
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RPM
I usually don't push an engine much beyond it's peak horsepower point. I can kind of feel where that point of diminishing returns is. It depends on engine condition and build up. But then I am kind of easy on my equipment. I prefer finesse, rather than brute force:-) There are some engines that just run sweet at high rpm's and seem to pull forever tho.
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From: Porterfield
RPM
>With a stock 2V carb, the engine wheezes out of breath by 4K
>rpm, obviously well below its mechanical capacity.
>
>I know of people who push stock 400s with 4V carbs to 6K rpm
>occasionally. Some of them haven't blown up yet.
The first year I was pulling open stock I blew up my good motor at the 5th pull of the season so I put my stock lower unit (Cast crank and rods with flat top pistons) With my reworked aussie heads in it as a back-up motor. In it's first pull I spun it to 7200 Rpm's it lasted 21 Sec. and died. Bearing Failer was the diagnosis.
OK this is what my machinist told me about stock 400's lower ends.
Don't spin them over 6200 Rpm's due to there no oiling to the piston pins other then splash oiling. Pins get hot get tight puts side loads on rod bearings which makes them hot and you end up spinning your rod bearings.
Sounded logical to me.
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RPM
OK, so how do we improve lubrication? I think the only Ford rod that uses an oil passage is a Nascar Boss 429. I thought all piston pins were splash lubricated. Wouldn't this be a problem on other motors?
What's the solution? Bronze bushings and floating pins? More rod bearing clearance? Oil cooler?
Truck pulls demand more from the engine than any drag strip could. I thought the 3" main journals were the problem because of too much bearing speed, and that was the reason they went to the cleveland size mains for a lot of the SVO blocks. Same thing with the 460.
What's the solution? Bronze bushings and floating pins? More rod bearing clearance? Oil cooler?
Truck pulls demand more from the engine than any drag strip could. I thought the 3" main journals were the problem because of too much bearing speed, and that was the reason they went to the cleveland size mains for a lot of the SVO blocks. Same thing with the 460.
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RPM
The Ertel pistons I am using have two broached slots along the pin that conducts oil along the piston pin. I have thought about drilling them to connect to the oil ring groove. The slots are at about 2 and 10 o'clock to the piston pin.
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From: space city
RPM
[updated:LAST EDITED ON 09-Sep-02 AT 01:06 PM (EST)]i have a set of 300 rods that have what appears to be an oil squirter on the big end of the rod. i wonder if the 240 rods have the same thing? the length & big end diameter of the 240 rods makes them look good for a stroker...
is this less of a problem with floating pins?
is this less of a problem with floating pins?
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