SBC enginetech headset

[bentvalves]

there are intake manifold coolant block of plates that i am instructed to install on engines 86 and up. says to install in "rear"

anybody familiar with these?

[BOOT]

Do they have a small hole?

[bentvalves]

Do they have a small hole?

they say block the rear, but gave me 4 plates.

one style has very small holes, the other style has larger holes.

very thoughtful of enginetech to put at least a half-hearted attempt at instructions in the box. idiots.

and they won't answer the phone.

do early model 350's have water circulation issues?

there are a bag of tiny set screws in the kit as well. what the hell are those for?

[rebelyell]

are you sure? ... those block off plates may be intended for the center ports which always carry exhaust gases (and are often partially or fully blocked).

[bentvalves]

i'll transpose their "directions" word for word in the morning.

"rear water ports in the intake manifold gasket" something or other.

[BOOT]

are you sure? ... those block off plates may be intended for the center ports which always carry exhaust gases (and are often partially or fully blocked).

The ones he has are TBI gaskets, Felpro uses a small hole https://pitstopusa.com/i-23916035-fel-p ... t-set.html

According to this discussion GM engineers would never do that because it would mess up the flow matrix or something viewtopic.php?f=1&t=64484

[BillK]

BV,
Just to explain. The TBI engines had a water passage in the intake manifold to run some heated water to the throttle body. The small holes metered the amount of water going through. If you have a "traditional" small block then your manifold will not have the water passage so there is no need for the restrictor plate.

[bentvalves]

engine came to me in a box out of an 1988 corvette.

it has two fuel rails and eight injectors, making it port injection.

thank you bill and boot.

[Schurkey]

BV,
Just to explain. The TBI engines had a water passage in the intake manifold to run some heated water to the throttle body. The small holes metered the amount of water going through.

Not exactly.

The small hole is there to bleed air or steam in the cylinder head, out the heater-core circuit.

The main volume of water for the heater core is from the water passage running through and under the intake, from the thermostat area to the heater outlet nipple.

As said...if you don't have the TBI-style intake manifold with the "water heating" passage, you don't need the gasket with the blocked rear coolant port.

Blocking the gasket forces water (coolant) to flow from the thermostat area rearwards, rather than from the head "upwards" to the heater core outlet nipple. With coolant flowing through the manifold, the manifold is heated evenly for good fuel vaporization.

Note that the typical heater core quick-connect nipple itself is restricted; the coolant passage is reduced to about a 1/4" hole, which has its own plastic divider further blocking the flow area. Best I can tell, this prevents dynamic over-pressurization of the heater core during high-rpm (high water-pump pressure) use.

[rebelyell]

engine came to me in a box out of an 1988 corvette.

it has two fuel rails and eight injectors, making it port injection.

thank you bill and boot.

88 w/8 port injectors sounds like TPI rather than TBI

[bentvalves]

BV,
Just to explain. The TBI engines had a water passage in the intake manifold to run some heated water to the throttle body. The small holes metered the amount of water going through. If you have a "traditional" small block then your manifold will not have the water passage so there is no need for the restrictor plate.

Hi bill,

ontop of the lower plenum right in the center there is a 2 bolt flanged little red box. the box has 3 micro holes threaded into in making a triangle. in the center of the triangle there is a small square hole.

what is this contraption, and does something affix to it? am i missing something?

[bentvalves]

bumped to the top.

'ol engine in a box dillema.

[Schurkey]

ontop of the lower plenum right in the center there is a 2 bolt flanged little red box. the box has 3 micro holes threaded into in making a triangle. in the center of the triangle there is a small square hole.

what is this contraption, and does something affix to it? am i missing something?

Photos? In focus, nicely-cropped and re-sized.

[bentvalves]

a vacuum diaphragm is missing from whatever is bolted to the plenum looking at stock photos.

[bentvalves]

I think it is time for me to become a member of AERA.