5 replies to this topic

[kimbo]

So I just took off my inlet manifold on a 78 VB 308 to discover 2 random bits of metal in the pollution ports on each side. One was in place and partially blocked the port. The other was inside and a bit munted up. Any clues on this shite?

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[kimbo]

Ok ...bit more research it seems like these were restrictors for the exhaust port crossovers. Not quite sure what the purpose is of these but the net effect is exhaust gases would heat the inlet manifold. Seems some guys completely block these ports.

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[yel327]

That's exactly what they are. The exhaust crossover has been used for years to help atomise the fuel and to run the auto choke. Earlier 253/308 used water to warm the intake and had a pipe through the exhaust manifold for choke.

 

On auto ADR27A 4.2/5.0 that exhaust in the intake was also used for the EGR valve.

Edited by yel327, 21 September 2023 - 06:40 AM.

[kimbo]

That's exactly what they are. The exhaust crossover has been used for years to help atomise the fuel and to run the auto choke. Earlier 253/308 used water to warm the intake and had a pipe through the exhaust manifold for choke.

On auto ADR27A 4.2/5.0 that exhaust in the intake was also used for the EGR valve.

I am staying with the quadrajet for now so I guess leave them open unless I want to drive around with the choke on for longer :-) ?

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[yel327]

Assuming it has an auto choke connected.

[kimbo]

Assuming it has an auto choke connected.

It does.

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