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Search found 1281 matches

by digger
Mon Jan 20, 2020 9:00 pm
Forum: Engine Tech
Topic: Sealers and thread lockers for final assembly
Replies: 34
Views: 691

Re: Sealers and thread lockers for final assembly

there is an application where you want a separate primer so have to use two (2) products as opposed to one (1)?
by digger
Mon Jan 20, 2020 7:41 pm
Forum: Engine Tech
Topic: Sealers and thread lockers for final assembly
Replies: 34
Views: 691

Re: Sealers and thread lockers for final assembly

loctite now has primerless products
by digger
Wed Jan 15, 2020 3:37 pm
Forum: Engine Tech
Topic: What is cylinder head choke
Replies: 18
Views: 1022

Re: What is cylinder head choke

Choke is an engineering term to signify sonic flow has been achieved, and at that point any increase in pressure ratio cannot increase velocity. This is not what happens in an intake port. I believe it is used commonly and incorrectly when a different aerodynamic phenomena occurs - flow separation....
by digger
Mon Jan 13, 2020 9:45 pm
Forum: Engine Tech
Topic: What is cylinder head choke
Replies: 18
Views: 1022

Re: What is cylinder head choke

its is fairly well know that increasing airspeed in the engine provides better "ramming" at the 2nd half of the lift curve (i.e peak lift to IVC) assuming things are setup fairly well with regard to intake manifold geometry, camshaft etc choke in the inlet port is when adding more velocity means the...
by digger
Thu Jan 09, 2020 10:07 pm
Forum: David Vizard forum
Topic: The 128 drama!
Replies: 65
Views: 2316

Re: The 128 drama!

David Vizard wrote: > Digger, > > I put value to your post contents so could I ask you to elaborate on this > as it could help me explain my procedures better. > > [b][i][color=#0000FF]this seems to agree with David’s work about the LSA > being “fixed” (not that I agree with the methodology put forw...
by digger
Wed Jan 08, 2020 4:58 am
Forum: David Vizard forum
Topic: The 128 drama!
Replies: 65
Views: 2316

Re: The 128 drama!

peejay wrote: > [quote="GARY C" post_id=842480 time=1578375960 user_id=21117] > [quote=digger post_id=842469 time=1578368433 user_id=6525] > I don’t think the port size has much to do with idle (other than low lift > curtain area ) it’s mostly the overlap and associated curtain area , > cylinder siz...
by digger
Tue Jan 07, 2020 6:29 am
Forum: David Vizard forum
Topic: The 128 drama!
Replies: 65
Views: 2316

Re: The 128 drama!

Garry the port velocity at idle is always bugger all such that making it a lot smaller has little effect on idle quality as it’s still extremely small
by digger
Tue Jan 07, 2020 1:20 am
Forum: David Vizard forum
Topic: The 128 drama!
Replies: 65
Views: 2316

Re: The 128 drama!

Gary, I never disagreed about changing the displacement that’s kinda different. F1 cars have a ton of curtain area and cams are about 270@0.040” for 4v not exactly small don’t have CL data It’s the curtain area not the port area. Fill in the ports 25% and the idle will not magically become good.
by digger
Mon Jan 06, 2020 10:40 pm
Forum: David Vizard forum
Topic: The 128 drama!
Replies: 65
Views: 2316

Re: The 128 drama!

I don’t think the port size has much to do with idle (other than low lift curtain area ) it’s mostly the overlap and associated curtain area , cylinder size and cross talking which is not the same as looking at LSA saying it will idle poorly . Small duration and 100LSA can idle fine, the same IR wil...
by digger
Mon Jan 06, 2020 7:01 pm
Forum: David Vizard forum
Topic: The 128 drama!
Replies: 65
Views: 2316

Re: The 128 drama!

OEM considerations (emissions, economy etc) for their camshaft choice is probably not the purpose of this thread where the stated method is for WOT performance It isn't, but check out to the two Honda figures showing overlap changing as a function of engine speed and load (which I assume would be t...
by digger
Mon Jan 06, 2020 6:30 pm
Forum: David Vizard forum
Topic: The 128 drama!
Replies: 65
Views: 2316

Re: The 128 drama!

OEM considerations (emissions, economy etc) for their camshaft choice is probably not the purpose of this thread where the stated method is for WOT performance
by digger
Sun Jan 05, 2020 11:34 pm
Forum: Engine Tech
Topic: Would you/do you use the K&N cone air filter?
Replies: 22
Views: 1325

Re: Would you/do you use the K&N cone air filter?

Some foam socks can be a big power loss on IR especially if they get oiled with the stuff they use on dirt bikes. Last time I made the mistake of doing that lost 30% power. Getting rid of the oil meant it was down only about 8%
by digger
Fri Dec 20, 2019 8:41 pm
Forum: Engine Tech
Topic: Rod bolt stretch
Replies: 19
Views: 912

Re: Rod bolt stretch

Tightening torque (with a torque wrench) only refers to the frictional force of threads, bolt head, and washer. It does not measure anything else. Depending on thread cutting method (cut, rolled or ground), the friction factor can range significantly (0.08 to 0.22). Tightening the bolt in several s...
by digger
Tue Dec 17, 2019 7:51 pm
Forum: Engine Tech
Topic: Valve springs
Replies: 18
Views: 919

Re: Valve springs

swampbuggy wrote:
Tue Dec 17, 2019 6:32 pm
^^^^^^^^ seriously, or is that a joke ??? Mark H. :?:
j/k
by digger
Tue Dec 17, 2019 4:40 pm
Forum: Engine Tech
Topic: Exhaust valve profile for average power
Replies: 4
Views: 566

Exhaust valve profile for average power

What are the trends going to be regarding exhaust valve lift curve on an optimised setup for something like a rpm band of say 2500-6500 e.g. old EMC rules where carrying the power past the peak and the peak number isn't particularly important at all. My thoughts are its not going to be anything like...