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Search found 1033 matches

by Geoff2
Sun Sep 22, 2019 5:08 am
Forum: Engine Tech
Topic: 270 magnum flat tappet idle speed and vacuum thoughts?
Replies: 19
Views: 737

Re: 270 magnum flat tappet idle speed and vacuum thoughts?

The RPM may make a few more HP at the cam's peak, but is very likely to give up some serious low/midrange torque. The std Performer would give the best overall performance with the 270 cam. That is why Edel makes two manifolds, not one, to cater for lower rpm engines & higher rpm engines.
by Geoff2
Sun Sep 22, 2019 5:01 am
Forum: Engine Tech
Topic: Sizing IR Carbs
Replies: 10
Views: 414

Re: Sizing IR Carbs

Were these Corvette intakes an IR design?
by Geoff2
Sun Sep 22, 2019 4:57 am
Forum: Engine Tech
Topic: Fuel Requirements
Replies: 17
Views: 446

Re: Fuel Requirements

David, you are making something that is quite simple......complicated.
by Geoff2
Sat Sep 21, 2019 5:40 am
Forum: Engine Tech
Topic: Fuel Requirements
Replies: 17
Views: 446

Re: Fuel Requirements

The displacement doesn't change throughout the rpm change. The density of the air drawn into the cylinders does. The original Urich/Fisher formula for fuel reqd v HP in the Holley book is as valid today as the day it was written.
by Geoff2
Sat Sep 21, 2019 5:33 am
Forum: Engine Tech
Topic: 270 magnum flat tappet idle speed and vacuum thoughts?
Replies: 19
Views: 737

Re: 270 magnum flat tappet idle speed and vacuum thoughts?

I would use the Performer manifold, not the RPM with this cam. The cam peaks about 5500 rpm, same as the Performer manifold. Don't know why you use a 5500 rpm cam with a 6500 rpm intake manifold.
by Geoff2
Wed Sep 18, 2019 4:55 am
Forum: Engine Tech
Topic: Sizing IR Carbs
Replies: 10
Views: 414

Re: Sizing IR Carbs

Weber 48 IDA is noted in one of DVs books as flowing 296 cfm per barrel. Factory choke/venturi size is 38mm. 45 DCOE with 38mm chokes 242 cfm per bl.
by Geoff2
Wed Sep 18, 2019 4:47 am
Forum: Engine Tech
Topic: Spring retainers and locks - mix and match?
Replies: 7
Views: 253

Re: Spring retainers and locks - mix and match?

You should only use collets designed to work with the diam of your valves. To mix sizes would mean that the collets are not supporting the load across the full circumference of the valve groove/bead.
by Geoff2
Sat Sep 14, 2019 5:31 am
Forum: Engine Tech
Topic: Torque To Yield
Replies: 30
Views: 848

Re: Torque To Yield

It is wrong to assume that if a bolt is rotated x amount of degrees, then the bolt will stretch y amount of inches. The amount the bolt stretches will depend on the material it is made of & the thickness/composition of the material it is clamping. The amount of 'stretch' could be shared by the bolt ...
by Geoff2
Sat Sep 14, 2019 5:23 am
Forum: Engine Tech
Topic: Low speed (1500-1800 RPM) driveability issue
Replies: 115
Views: 2673

Re: Low speed (1500-1800 RPM) driveability issue

I have had the same experience as Tuner using a slot-in plenum divider. It came loose. It just goes to show how much pulsing is going inside the intake manifold.
by Geoff2
Wed Sep 11, 2019 5:20 am
Forum: Engine Tech
Topic: Low speed (1500-1800 RPM) driveability issue
Replies: 115
Views: 2673

Re: Low speed (1500-1800 RPM) driveability issue

It is the 'big cam behaving badly syndrome'. There are some things that should be checked. Popping exhaust is NOT normal; could be valve adjustment, wiped lobe, etc. Definitely do NOT use an open spacer. That will only make the surging worse. Keep the plenums divided for max vacuum. Try backing out ...
by Geoff2
Sun Sep 08, 2019 6:34 am
Forum: Engine Tech
Topic: Intake port opinions.
Replies: 24
Views: 1604

Re: Intake port opinions.

A mate of mine built a double Triumph, using 650 engines, around 1969-70. This was in Sydney, Australia. The rear engine was a unit construction engine, front engine was pre unit. I am going from memory now, he lengthened the standard Triumph frame about 15". The bike was street registered. I rode i...
by Geoff2
Sun Sep 08, 2019 5:46 am
Forum: Engine Tech
Topic: BLP 4150 Transition Slot Questions
Replies: 3
Views: 377

Re: BLP 4150 Transition Slot Questions

I have had carbs with twisted shafts that cause uneven transfer slot opening. Have always been able to fix it twisting the shaft back to the correct position.
by Geoff2
Thu Aug 29, 2019 5:04 am
Forum: Engine Tech
Topic: Improved engine throttle responce
Replies: 23
Views: 1200

Re: Improved engine throttle responce

The shear plate hangs over the edge of the venturi. Seems that might affect the smooth airflow into the venturi, cause turbulence & affect fuel metering from the booster.
by Geoff2
Thu Aug 22, 2019 5:59 am
Forum: Engine Tech
Topic: Spark plugs- ground strap”tech”?
Replies: 35
Views: 1964

Re: Spark plugs- ground strap”tech”?

Dave K.
I was using GM HEI with the MSD 7.5 amp module. I see many people dismiss any new type of spark plug as a 'gimmick'. Maybe. Maybe not.
When the projected nose core plugs arrived in the 60s, I'll bet many called them a gimmick. Now their use is just about universal with NA production cars.
by Geoff2
Thu Aug 22, 2019 5:51 am
Forum: Engine Tech
Topic: 42 DCNF's on a Mopar 440
Replies: 89
Views: 8804

Re: 42 DCNF's on a Mopar 440

Harry. No didn't change IABs. They are fixed on IDFs. My theory is that if changeable air bleeds were necessary, they carb would be made that way. I have never had a flat spot or stumble going from idle to cruise with just light throttle opening. It is exceptionally smooth actually. The problem I wa...