Portiing the heads for performance....

[jibbby]

I am thinking of porting the heads on the 1uz-fe myself to create better flow maybe as soon as next weakend.. I have done this on a few of my older SBC heads where I would remove the Chevy heads then line up the gaskets and grind out all the head port holes edges in a circular grind motion to then create a smoother and larger port hole to meet up with where the gasket fits. Then I would finish the job by using a fine grit hand held circular sander to basically smoothe out and polish all the grinded areas.. I would imagine it is no different with the 1uz-fe motor heads... I would always pick up a few ponies when doing this on my SBC heads and exhaust manifolds too where the headers meet up....

I would like to do this same process with my 1uz-fe heads and then really sand and polish out those carefully grinded out circular edges (port holes) to create the best air flow possible.... I always did this by hand by using a hand held circular rotation grinder tool in the past... Grinder and sander bits..

Question, will it make a difference if I do this, and do you think it worth the trouble? Also, I have never really taken a close look at the 1uz-fe head port holes, is there areas on the head port holes that can be grinded like I am talking about? What do you guys think?

Maybe I should have posted this in the Head and intake section...ooops...

 

[Toysrme]

It's not the port matching that helps you. it's unshrouding the valves, blending the short side radious, and fiddling with the bowls.
=)
The best thing to do is all of the above, before-hand grinding & sanding the combustion chamber as smoothely as practical. (That'll keep carbon build-up to a minimum, and hence. One more source of pre-ignition.) Then do all your porting work. Then have someone put a 3-angle valve job on there to finish it off. (Or have them unshroud the valves as the same time)

Without radical changes to the engine's breathing. Gasket matching is much more show than performance. It's the other goodies that really get ya going!

 

[jibbby]

Yeah, I hear you Toys about the three angle valve job and doing the entire heads and what not....I just wanted to do a few things myself in the old backyard with a table and a couple of my tools one weekend...

One other question for ya? Do you always have to resurface these 1uz-fe heads after removing them? I've have yet to remove the heads on an 1uz-fe motor so I am kinda learning as I go.... How many ponies can you realistically pick up with some good head work on these early model 1uz-fe motors?

 

[Anaema]

you shouldn't have to. resurfacing means you(or someone else) has overheated the engine in the past and warped the heads, or you want higher compression. you might have to replace the head bolts and head gasket, i can't think of anything more than that.

 

[plman]

Flow numbers 98 GS400 heads

Here are ported numbers: Street Port only
Heads were flow tested before and after:
Factory Completed
[email protected] 177.2@150.
212.0@200 226.5@
249.5@250 259.5@
195.9@300 271.9@
196.8@350 281.0@

These heads are brand new and fitted with new cams, etc. I have considered selling them along with a block I have. No time to work on any more.

 

[ToranaJudd]

Hey plman,

Are they standard valves? If not what did you use and did you oversize the seats? Also, the second pic isn't working. Can you please send it thru? If you are thinking of selling PM me a price you are after (if they include aftermarket cams).]

Cheers, Judd.

 

[Toysrme]

No, you don't have to resurface heads. But it costs so little you might aswell. Tell the builder what kind of gasket you're using & if they're really high end, they'll leave whatever the corrisponding "best" finish is on the head to grip that kind of gasket.

You can do everything but the valve angles yourself. Or atleast get started on it. If you're going to unshroud the valves tho, have some sacraficial valves on hand!


There's like two basic porting guides on the net. Check those out.

 

[jibbby]

PLM - nice heads... nice results.... Aren't the 98 GS400's the VVTi motors?


Toys - Do you have any hands on experience with porting and polishing these heads? It sounds like you are the man.....

Question for ya - What's the deal with these 3 angle valve head jobs?...What makes then so wonderful over stock? Do they really flow that much better?

Thanks for the replies....

 

[plman]

Yes, 98 GS400 are the VVTi motors. Darn fine engine. Has lots of potential.

 

[jibbby]

Lot's of potential for what? Not for boosting (VVT-i) or pushing over 400whp... N/A speaking, "yes" with just the basic external mods.... I would prefer the earlier 1uz.. model non vvt-i motors for boost applications... No boost VVt-t motors for sure......

 

[UZZ30-Québec]

VVT-I heads have more potential

3 angles valve job (or 5 angles) make the valve seats better and perform a better seal. you'll reduce your leakdown if you do a leakdown test. if you reduce leak down, you get more power from the energy you release in the explosion.

 

[jibbby]

Can VVt-i heads be used and converted to work with a non vvt-i motor?

 

[UZZ30-Québec]

I don't know.

well, one thing for sure, you can use VVT-I heads and not use the VVT-I system. If you get custom cams, the flow from the heads will help and if the VVT-I doesn't work, it's just like a normal 1UZ.

Maybe the best way would be to use 1st gen 2UZ heads since they are not VVT-I but have bigger ports from what i've read.

 

[jibbby]

That's exactly what I was thinking......