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SBC various Vortec Dyno Tests and Flow Sheets

General engine tech -- Drag Racing to Circle Track

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maxracesoftware
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Re: SBC various Vortec Dyno Tests and Flow Sheets

Post by maxracesoftware »

MELWAY wrote: Tue Dec 11, 2018 3:53 pm Larry
Are these all running a true HYD flat lifter?
Have you experimented with different preloads or are you your running them lashed?
Cheers James
all those Engines are running Rhoades Hydraulic Flat Tappet Lifters

Have you experimented with different preloads or are you your running them lashed?

Chris has on some of our Tests ... but i admit i'm typing down Info into WinDyn as Chris says the changes he makes
and sometimes in a hurry to do so ... some of the Info could be misunderstanding on the Hot Lash settings that are on the Dyno sheets ??

i'll ask/clarify Wednesday when we Dyno again

EDIT : i do a few Dyno tests with the Air Turbine to see if we are "Floating Valves "
Lashing Hydraulic Lifters tests shows up on the Air Turbine also
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MELWAY
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Re: SBC various Vortec Dyno Tests and Flow Sheets

Post by MELWAY »

Thankyou Larry
Are you saying you have seen negative effects from running lash on Hyd flat lifters
We have some classes over here that mandate a HYD flat cam. And I’m not having much fun trying to rev them past 7500 and most lifters these days seem to bleed down excessively and be unreliable
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maxracesoftware
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Re: SBC various Vortec Dyno Tests and Flow Sheets

Post by maxracesoftware »

MELWAY wrote: Tue Dec 11, 2018 4:20 pm Thankyou Larry
Are you saying you have seen negative effects from running lash on Hyd flat lifters
We have some classes over here that mandate a HYD flat cam. And I’m not having much fun trying to rev them past 7500 and most lifters these days seem to bleed down excessively and be unreliable
YES .... too much Valve Lash lost 25 HP top end :(
just enough = more HP 8)

also we run a lot of Oil Pressure in these Engines
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Re: SBC various Vortec Dyno Tests and Flow Sheets

Post by GARY C »

maxracesoftware wrote: Tue Dec 11, 2018 4:26 pm
MELWAY wrote: Tue Dec 11, 2018 4:20 pm Thankyou Larry
Are you saying you have seen negative effects from running lash on Hyd flat lifters
We have some classes over here that mandate a HYD flat cam. And I’m not having much fun trying to rev them past 7500 and most lifters these days seem to bleed down excessively and be unreliable
YES .... too much Valve Lash lost 25 HP top end :(
just enough = more HP 8)

also we run a lot of Oil Pressure in these Engines
Are there rules against limiting travel or setting lifter at the bottom?
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Re: SBC various Vortec Dyno Tests and Flow Sheets

Post by MELWAY »

I guess you could limit travel
I have seen the consequence of too much pre load when they over rev them and float valve the lifter pumps up and valves crash into Pistons. So I’m trying to run zero pre load or some lash to. Avoid this
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Re: SBC various Vortec Dyno Tests and Flow Sheets

Post by PRH »

I’m curious about what the vacuum reading is measuring.
It’s quite a bit different on the stock heads after they’ve been reworked than the other tests.

I see this is a 2 year old thread...... apologies.
Somewhat handy with a die grinder.
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Re: SBC various Vortec Dyno Tests and Flow Sheets

Post by maxracesoftware »

PRH wrote: Fri Oct 16, 2020 1:51 pm I’m curious about what the vacuum reading is measuring.
It’s quite a bit different on the stock heads after they’ve been reworked than the other tests.

I see this is a 2 year old thread...... apologies.
the difference in vacuum readings are :
for 1 engine its Plenum vacuum readings
and for the other engine its Vacuum Pump readings
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