Heat riser Block off plate

[LandoNick]

Not sure what you're asking here, but if you're referring to the thing with the three-holes in it, that's an upgraded replacement Stainless Steel flange for the one that's welded to the top of the downpipe, that bolts to the underside of the exhaust manifold.


View attachment 3564119

not a direct question about the flange. I will be replacing the downpipes piece. the "branch" pipe that comes off the downpipe hooks to the brass contraption under the hood. Do I need that brass contraption if I am not running an air pump?

 

[Spike Strip]

not a direct question about the flange. I will be replacing the downpipes piece. the "branch" pipe that comes off the downpipe hooks to the brass contraption under the hood. Do I need that brass contraption if I am not running an air pump?

No. That pipe is for air that is diverted directly into the down pipe. No air pump, no air.

 

[ToyotaMatt]

Last question on this topic and a wrap up!. What type of steel and what gauge/thickness has everyone used for the riser block plate?

I always appreciate when someone assembles ALL of the information learned from multiple conversations in one place. So here goes:

-The heat riser is a known point of failure in the exhaust manifold. The press-in bushing/bearing on the fire wall side of the manifold is what leaks. The general consensus is to simply remove the heat riser mechanism entirely. Use a dremel to cut out the plates and the rod of the heat riser.
-The best and longest lasting method for filling the resulting holes on either side of the manifold is to tap(thread) and plug with a threaded plug. A spot weld to prevent the plug from coming loose is an option. Welding a plug in to both ends is an option but requires a skilled knowledgable welder to weld cast iron.
-You want to replace the heat riser with a metal plate that sits between the exhaust and intake manifolds. This plate will prevent the intake manifold from cracking by getting overheated, but still allow the transfer of heat. The intake is made of aluminum. Exhaust is made of cast iron.
-There is no air or exhaust that transfers between the intake and exhaust manifold. The reason for the connection between the two is to transfer heat. If the air coming in to the intake manifold is too cold, especially when starting the engine, the gas won't aspirate with the air making it harder to fire.
-It is a common issue for the base of the intake manifold to crack because of the overheating previously mentioned. If this is the case, then, when you are installing the metal plate between the two manifolds you put a gasket on BOTH sides of the metal plate to seal top and bottom. If the intake is not cracked, then a gasket between the exhaust manifold and the plate is the only one you need.

Separately, but also part of the exhaust leak journey... The flange connection at the bottom of the exhaust manifold where it connects to the exhaust pipe takes a donut style gasket. There is no other gasket, meaning no reflex or cutout gasket that fits there. There is a cutout gasket for the EGR down tube. And obviously a single gasket for both manifolds where they connect to the head.

Other learnings. If you're replacing the studs on the manifold use anti-seize so you can get them out next time.

@cruiseroutfit

Cruiser outfitters in salt lake offer the good one , right gauged metal and all



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Heat Riser Block Off Plate - Fits 1/1975 - 8/1987 5-Bolt Style 2F 4x/5x/6x Applications (EGEXHRPL)

Toyota Land Cruiser Heat Riser Block Off Plate

cruiserteq.com

x 2 of these also

Intake & Exhaust Manifold Heat Riser Gasket - Fits 1/1975 - 8/1987 4x/5x/6x 5-Bolt Style Applications (EGEX61011)

Toyota Land Cruiser Intake & Exhaust Manifold Heat Riser Gasket

cruiserteq.com

,
ALL NOW OEM Bolts 100 % !


,.

 

[ToyotaMatt]

back in 1998 my T-TEN professor calculated the extra air flow volume simply removing the shaft and flapper in the Normal running HOT correctly moving position

this =m

The faster the air can GET OUT the exhaust ....

the faster it can thus in-take in ....

this is not a joke , it was figured on a old skool rolling dyno


it was notably notable


.
.

​

 

[Beehanger]

I used two gaskets because I had a crack in my intake. One between block off plate and intake to seal that, then second gasket between exhaust manifold and block off plate to seal exhaust. I also completely removed heat riser plate assembly. I had a pretty sizable leak coming out from hole closest to firewall.
So if you have a crack in your intake ( causing vacuum leak) you need two gaskets if your intake is fine then one gasket should be fine. That’s my take on this.

How does this resolve an intake leak? Where was your crack?

 

[GetSandyFJ60]

How does this resolve an intake leak? Where was your crack?

The crack tends to happen T the base of the intake where it connects to the exhaust because of high heat over time. Sealing both with gaskets on either side of the block off plate should resolve the intake leak.

I’m doing this tomorrow. I would still appreciate feedback on the gauge of metal used for the block off plate. I’ve made a 16 gauge which is pretty thick and a 22gauge which is thinner. Not sure which will work better.

 

[GetSandyFJ60]

Also, this was our solution for filling the holes from the heat riser. Bolts, nuts and washers, tack welded so the nut won’t come loose.

 

[mdw83fj60]

How does this resolve an intake leak? Where was your crack?

Exactly this. Right above the heat riser, mine was because the heat riser failed and was always open exposing bottom of intake to exhaust heat all the time.

The crack tends to happen T the base of the intake where it connects to the exhaust because of high heat over time. Sealing both with gaskets on either side of the block off plate should resolve the intake leak.

I’m doing this tomorrow. I would still appreciate feedback on the gauge of metal used for the block off plate. I’ve made a 16 gauge which is pretty thick and a 22gauge which is thinner. Not sure which will work better.

 

[mdw83fj60]

The crack tends to happen T the base of the intake where it connects to the exhaust because of high heat over time. Sealing both with gaskets on either side of the block off plate should resolve the intake leak.

I’m doing this tomorrow. I would still appreciate feedback on the gauge of metal used for the block off plate. I’ve made a 16 gauge which is pretty thick and a 22gauge which is thinner. Not sure which will work better.

Wish I could help on what gauge metal to use on block off plate, I purchased my set up from Cruiser Outfitters Heat Riser Block Off Plate - Fits 1/1975 - 8/1987 5-Bolt Style 2F 4x/5x/6x Applications (EGEXHRPL) - https://cruiserteq.com/heat-riser-block-off-plate-fits-1-1975-8-1987-5-bolt-style-2f-4x-5x-6x-applications-egexhrpl/
I like the bolt and washers to block off the holes. I did that over a year ago and no issues.

 

[CruiserTrash]

For $25, why would anybody try to reinvent the wheel on a block off plate? You wouldn’t save any money.

 

[GetSandyFJ60]

For $25, why would anybody try to reinvent the wheel on a block off plate? You wouldn’t save any money.

Because it’s apart in the carport of my retired mechanic friend. It was a 1-2 day project until discovering the riser and gasket are the issue and not the manifold connection to the head. So I fabricated two gaskets to get it done and out of his driveway rather than waiting days for delivery. Not buying another one because why would anyone own 3? Still hoping someone has an opinion on gauge of metal. Thanks for asking.

 

[micruz60]

Because it’s apart in the carport of my retired mechanic friend. It was a 1-2 day project until discovering the riser and gasket are the issue and not the manifold connection to the head. So I fabricated two gaskets to get it done and out of his driveway rather than waiting days for delivery. Not buying another one because why would anyone own 3? Still hoping someone has an opinion on gauge of metal. Thanks for asking.

It looks like 4mm on the original assembly.

Or slightly less than 3/16 inch = 7 gauge steel.
HTH

 

[GetSandyFJ60]

It looks like 4mm on the original assembly.

View attachment 3574693

Or slightly less than 3/16 inch = 7 gauge steel.
HTH

Thanks so much! Really appreciate the photos