DIY Port and Polishing

[trd_st184]

I was wondering what the thoughts of DIY port and polishing are?

I've heard the following points:

- Exhaust side of the exhaust should be polished/mirror finish

- Intake Side of the exhaust should be without any burrs or high spots

- Runners on the intake side should be Knife-edged

Has anyone got any DIY shots/advice?

[thechuckster]

join performance forums, read all technical threads by 'TK' particularly those on porting, re-read.

fwiw: for your first go, i'd suggest port-matching the induction side of the 3sgte head/TVIS/manifold. Forget the polishing bit.

[Billzilla]

Forget the polishing bit.

I'm still amazed people recite that line like a parrot.

[thechuckster]

Bill: the port-n-polish or not-to-polish lines?

... on the intake side you want a 80-120grit finish - a polish on the exhaust side and combustion chamber is going to give you slightly better heat rejection - and something that you'd only notice if looking for a 1% improvement on an already twitchy engine.

[trd_st184]

This work is being done to a 5sfe. The guys in America are getting pretty big numbers (for a NA motor) out of 5sfe motors with a decent port/polish and a mild cam. So i'm working towards that sort of set up

[Billzilla]

Bill: the port-n-polish or not-to-polish lines?

People just rattle off 'port & polish' without thinking because it's what they've heard. Polishing went out in the 60's for people that know what they're doing with engines.
I don't think it's worth much in the chamber & exhaust port either as they get a nice carbon coating a few seconds after the first start anyway.

[Hen]

The guys in America are getting pretty big numbers (for a NA motor) out of 5sfe motors with a decent port/polish and a mild cam.

Don't get your hopes up too much over that sort of thing. All too often internet power figures are overstated and American dyno figures are overstated.

Some smart headwork and bigger cams should give improvements, but won't set the world alight in a 5SFE.

[oldeskewltoy]

For a 4AG... think "bowl clean-up/correction" not really port and polish.

blending the valve seat into the surrounding casting does wonders....

concerning polishing the exhaust side.... I look at it this way... a polished surface here holds less build up then a rougher surface. Ive seen some heavy build up often anchored on a casting flaw.

[Joshstix]

I'd be looking at swapping a 3S-GE head and cams onto it personally rather than playing around with the 5S head porting and buying cams for it.

[J0RD0]

^^^ my thoughts exactly, the f series head is designed for economy, the g series head is designed for performance. Why would you bother with a f series head when toyota have already done the hard work for you?

Remember F series . . . economy

[ed]

f vs g statements are generally incorrect

[Z2TT]

What about the 1uz-fe, It has an "F" head and many consider it a performance engine.

[JustCallMeOrlando]

One of the reasons the theory doesn't always hold true.

[Joshstix]

Yeah not really interested in the genralisations but the flow numbers I've seen for the *S-GE and *S-FE heads show that the GE heads flow a lot more air. There is also a lot more parts available for them to improve that flow at a cheaper price than the FE heads, plus the 5S exhaust manifold will bolt straight up to a gen 2 3S-GE head.

I don't doubt that the flatter combustion chamber of the FE head could make more power in an all out build but for someone asking about home port jobs I think a bolt on head with significantly better flowing ports and more agressive cams is a simpler solution that will give good results for the effort and money involved.