| TALES OF THE ALUMINUM MANIFOLD [message #69903] |
Thu, 07 January 2010 11:19  |
Michael Bozardt
Messages: 367
Registered: January 2007
Location: College Station, Texas
Karma: 1
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Senior Member |
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Bought a Dick Paterson carb and after removing the old one, saw that the intake manifold was cracked in three places down to and into the crossover.
After checking several sources, was convinced that it could not be adequately repaired.
Opted-is there a choice?- to buy the alauminum manifold now offered by the two Jims made especially for the GMC motorhome.
I have a few comments on the installation:
1) buy the gaskets also and throw away the "turkey tray"(the metal tray under the manifold that serves as a gasket for the manifold). Use high temp sealant to hold the gaskets to the manifold for installation purposes.
2) Buy an electric choke-note that Paterson puts one in his rebuilt carbs.
3)Use a high temp gasket sealant to place the two end pieces of the gasket set(small curved rubber pieces that attach to the block).
4) Note the water connecting "T" at the rear of the manifold is corroded and it also is the wrong size for the aluminum manifold.
Bought an aluminum replacement(from O'Reilley's) that fits but has a 3/4 inch connection for the hose. Connecting hoses are 1/2 inch so get a 1/2x 1/2x 3/4 plastic "T" from Home Depot or Lowe's.
5)Note there is a round, raised casting that interfers with the throttle linkage plate that bolts to the rear of the carb. The casting is higher than the plate. My solution was to put spacers under the plate to raise it up and then use longer bolts to secure it to the carb. Others have simply bent the plate.
6) Find an appropriate place to connect the electric choke. I have not done this yet. Anxious to fire it up-don't forget to replace the coolant in the radiator!!
7)BTW, I removed the large A/C bracket from over the right valve cover and two brackets from the manifold to the radiator shroud. I did not disturb the tension on the A/C belt doing it this way.
Michael at GEMRECS
[Updated on: Thu, 07 January 2010 11:21] Report message to a moderator |
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| Re: [GMCnet] TALES OF THE ALUMINUM MANIFOLD [message #69934 is a reply to message #69903] |
Thu, 07 January 2010 14:48  |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Michael,
I too fitted an aluminum manifold this past summer and have some comments
regarding your comments. See CAPS below.
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Michael Bozardt
Sent: Friday, 8 January 2010 4:19 AM
To: gmclist@temp.gmcnet.org
Subject: [GMCnet] TALES OF THE ALUMINUM MANIFOLD
Bought a Dick Paterson carb and after removing the old one, say that the
intake manifold was cracked in three places down to and into the crossover.
COMMENT: IMHO IF YOU HAVE A CAST IRON MANIFOLD ON A GMC THAT IS NOT CRACKED
AFTER 30 PLUS YEARS OF CARB HEAT YOU ARE LUCKY - BIG TIME!
After checking several sources was convinced that it could not be adequately
repaired.
COMMENT: WELDING CAST IRON IS A BITCH, I LEARNED THAT WHEN I TOOK A WELDING
COURSE AT SYDNEY TECH LAST YEAR!
Opted-is there a choice? - to buy the alauminum manifold now offered by the
two Jims made especially for the GMC motorhome.
COMMENT: YOU CAN BUY AN EDELBROCK BUT THEN YOU HAVE TO BLOCK OFF THE CARB
HEAT AND BUILD A RAISED ENGINE COVER. THE EDELBROCK WOULD SAVE YOU ABOUT
$300 THOUGH.
I have a few comments on the installation:
1) buy the gaskets also and throw away the "turkey tray"(the metal tray
under the manifold that serves as a gasket for the manifold). Use high temp
seatant to hold the gaskets to the manifold for installation purposes.
COMMENT: I FOUND THE GASKETS BELOW. UNFORTUNATELY IT WAS AFTER I INSTALLED
THE MANIFOLD! I RECKON THE STEEL CORE WOULD PROTECT THE ALUMINUM MANIFOLD
WHERE IT CAME INTO CONTACT WITH THE CARB HEAT PORTS IN THE HEADS. JIM K HAS
NOTED THAT'S NOT A PROBLEM BUT WHAT THE HEY!
http://www.summitracing.com/parts/EDL-7284/?image=large
Here's the text from the ad:
Brand: Edelbrock
Manufacturer's Part Number: 7284
Part Type: Intake Manifold Gaskets
Product Line: Edelbrock Intake Manifold Gaskets
Summit Racing Part Number: EDL-7284
Port Style: Stock
Port Height (in): 2.440 in.
Port Width (in): 1.440 in.
Gasket Material: Composite
Thickness (in): 0.060 in.
Quantity: Sold as a set.
Notes: Nitrile bead around port openings.
Produce maximum and efficient power with precise sealing.
Properly sealing an engine is paramount to making maximum horsepower.
Edelbrock intake manifold gaskets are designed to give your manifold and
cylinder heads an exact seal with their composite and steel core
construction.
Note the Nitrile bead and steel core!
2) Buy an electric choke-note that Paterson puts one in his rebuilt carbs.
COMMENT: I USED THIS ONE:
http://www.napaonline.com/Search/Detail.aspx?R=CRB21603_0177794562
3) Use a high temp gasket sealant to place the two end pieces of the gasket
set (small curved rubber pieces that attach to the block).
COMMENT: JOHN SHARPE SUGGESTED WE USE THE BLACK HI-TEMP SILICONE THAT COMES
IN A PRESSURIZED CAN, IT WAS MUCH EASIER TO GET A NICE EVEN BEAD ACROSS THE
FRONT AND BACK OF THE BLOCK.
4) Note the water connecting "T" at the rear of the manifold is corroded and
it also is the wrong size for the aluminum manifold.
Bought an aluminum replacement(from O'Reilley's) that fits but has a 3/4
inch connection for the hose. Connecting hoses are 1/2 inch so get a 1/2x
1/2x 3/4 plastic "T" from Home Depot or Lowe's.
COMMENT: IMHO I WOULD NOT USE PLASTIC; THE WATER TEMP IS A CONSTANT 180° OR
HIGHER DEPENDING ON WHAT THERMOSTAT YOU HAVE INSTALLED. MY GMC HAS A
GALVANIZED "T" WITH HOSE BARBS ON ALL THREE OUTLETS. THE OEM FITTING IN THE
MANIFOLD IS 3/4" PIPE AND HAS A RESTRICTOR IN IT WHICH LIMITS THE FLOW. THE
ONE IN THE ALUMINUM MANIFOLD IS 1/2" PIPE. I REPLACED THE OEM FITTING WITH
BRASS 1/2" PIPE TO 5/8" HOSE BARB. I TAPPED THE BARB END WITH A 1/4" PIPE
TAP AND SCREWED A 1/4" PIPE PLUG IN IT. I CUT OFF THE SQUARE DRIVE AND
DRILLED A HOLE IN IT THE SAME SIZE AS THE RESTRICTOR (SORRY I CAN'T REMEMBER
THE SIZE).
5) Note there is a round, raised casting that interfers with the throttle
linkage plate that bolts to the rear of the carb. The casting is higher than
the plate. My solution was to put spacers under the plate to raise it up and
then use longer bolts to secure it to the carb. Others have simply bent the
plate.
COMMENT: I WAS ABLE TO NOTCH THE END OF THE PLATE TO CLEAR THE PORT F.I.
BOSS ON THE ALUMINUM MANIFOLD.
6) Find an appropriate place to connect the electric choke. I have not done
this yet. Anxious to fire it up-don't forget to replace the coolant in the
radiator!!
COMMENT: KEN BURTON HAD COMMENTED ON THIS BEFORE BUT I CAN'T FIND THE EMAIL.
7) BTW, I removed the large A/C bracket from over the right valve cover and
two brackets from the manifold to the radiator shroud. I did not disturb the
tension on the A/C belt doing it this way.
COMMENT: THE HOLE MY MANIFOLD DID NOT LINE UP WITH THE A/C BRACKET SO I
SLOTTED IT. WHEN I TIGHTENED IT DOWN I CRACKED THE BRACKET. BE CAREFUL!
Michael at GEMRECS
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] TALES OF THE ALUMINUM MANIFOLD [message #69939 is a reply to message #69934] |
Thu, 07 January 2010 15:38 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Senior Member |
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Agree with Rob on NOT using the plastic "T" in the coolant line. I had a bubble in my coolant line (back to the rear hot water heater), that was replaced with plastic fitting. On trip returning home, the plastic fitting failed resulting in loss of coolant and eventually cracked head and cracked block. No plastic fittings for me.
Tom Phipps,
75 GMC Ex-Avion
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] TALES OF THE ALUMINUM MANIFOLD [message #69951 is a reply to message #69903] |
Thu, 07 January 2010 17:03 |
Rick Denney
Messages: 430
Registered: January 2004
Karma: 0
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Senior Member |
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Michael Bozardt writes...
> 1) buy the gaskets also and throw away the "turkey tray"(the metal
> tray under the manifold that serves as a gasket for the manifold).
> Use high temp seatant to hold the gaskets to the manifold for installation purposes.
Dick Paterson's gaskets are the best, in my view. He provides
instructions on where to put the sealant (around the waterjackets and
long the bottom edge of the ports to seal the lifter galley). The
stainless plates will protect the aluminum from erosion.
It's easier to stick the gaskets to the heads, and then drop the
manifold on them. Take a bolt, cut off the head, round it with a
grinder, and screw it into a manifold bolt hole on each side before
dropping the manifold--they will help with alignment. Then, remove
them and replace with the manifold bolts.
> 3)Use a high temp gasket sealant to place the two end pieces of the
> gasket set(small curved rubber pieces that attach to the block).
Better yet, throw those end gaskets away and seal the end gaps with a
good-sized bead of high-temp silicone. Smoosh the manifold down onto
the bead, and then let the bead cure before running the engine. Clean
the surfaces with alcohol first to remove any trace of oil or grease.
> 4) Note the water connecting "T" at the rear of the manifold is
> corroded and it also is the wrong size for the aluminum manifold.
> Bought an aluminum replacement(from O'Reilley's) that fits but has
> a 3/4 inch connection for the hose. Connecting hoses are 1/2 inch so
> get a 1/2x 1/2x 3/4 plastic "T" from Home Depot or Lowe's.
The factory fitting on mine was just a plain, straight tubing adapter.
Found a replacemend on the Help rack at Advance Auto, complete with a
slightly smaller opening similar to the original.
> 5)Note there is a round, raised casting that interfers with the
> throttle linkage plate that bolts to the rear of the carb. The
> casting is higher than the plate. My solution was to put spacers
> under the plate to raise it up and then use longer bolts to secure
> it to the carb. Others have simply bent the plate.
Or grind that boss down a bit. Gary left those bumps on the casting to
provide places for people to machine threaded holes for port
injection. Those not intending to do that can grind them for clearance
where needed.
Rick "some will need to replace on manifold bolt to get the correct
length, too" Denney
'73 230 Ex-Glacier "Jaws"
Northern Virginia
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'73 Glacier 230 "Jaws"
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