Port n polish during header install - Toyota 4Runner Forum

ElDuck · 03-26-2020, 10:23 PM

Has anyone done any porting/polishing or port matching the exhaust to their Doug Thorley headers during install? Or not enough room?

Just curious as I'll be doing mine in the next few weeks.

xtremewlr · 03-27-2020, 11:47 AM

Quote:

Originally Posted by ElDuck

Has anyone done any porting/polishing or port matching the exhaust to their Doug Thorley headers during install? Or not enough room?

Just curious as I'll be doing mine in the next few weeks.

You don't want to do a port/polish with the heads on the truck still.

Lack of room.
Too much debris from the work.
Can't see shit.

Inv4drZm · 03-27-2020, 12:21 PM

Does anyone even port and polish the exhaust? I can see why on the intake, but polishing the exhaust seems futile, it's just going to have a layer of carbon build up on it.

Terminator03 · 03-27-2020, 12:34 PM

Quote:

Originally Posted by Inv4drZm

Does anyone even port and polish the exhaust? I can see why on the intake, but polishing the exhaust seems futile, it's just going to have a layer of carbon build up on it.

This! Plus, the only way to do properly is with heads removed and disassembled completely because porting involves machining or grinding for material removal and reshaping the ports, neither of which you can do without getting chips, and other abrasive materials into the valves, guides, seals, etc., which is obviously no bueno. That is not even mentioning getting into the intake tract, which should be obvious as not ideal. Then, there is the negligible gains without proper cams, compression, etc. to take advantage of the added flow...

rdruss · 03-27-2020, 12:43 PM

Quote:

Originally Posted by Terminator03

This! Plus, the only way to do properly is with heads removed and disassembled completely because porting involves machining or grinding for material removal and reshaping the ports, neither of which you can do without getting chips, and other abrasive materials into the valves, guides, seals, etc., which is obviously no bueno. That is not even mentioning getting into the intake tract, which should be obvious as not ideal. Then, there is the negligible gains without proper cams, compression, etc. to take advantage of the added flow...

You can't just go in there and hack away thinking that bigger is better, or whatnot. There's a little science and skill involved in porting heads. That's why it's not cheap for an effective job.

Ed_C · 03-27-2020, 12:53 PM

Quote:

Originally Posted by Inv4drZm

Does anyone even port and polish the exhaust? I can see why on the intake, but polishing the exhaust seems futile, it's just going to have a layer of carbon build up on it.

The header ports should be larger than the cylinder head exhaust ports to reduce the chances of exhaust reversion, so I'd leave the heads alone.

Exhaust Reversion

ElDuck · 03-28-2020, 01:33 AM

When I initially.posted this, I was a little tired and not thinking very well apparently. All good points. Thanks guys!

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