AFR165 port question: Is it slightly ridgy on purpose?

crazypete · Sep 20, 2005

I am cleaning up a set of 165's to install 200 pounder triple springs. There is a lot of carbon caked in there for a set of heads the SUPPOSEDLY only has 1500 miles in it (how much carbon should 1500 mile heads have in there). Lots of oil sitting on top of the intake valve too (how much is supposed to slip past the seals?)

Anyways... the ports seem to have a regular series of lines (think of a cross section of an onion) from the porting machine I assume. Are these leftovers of the porting process or some form of intentional roughness to keep the mixture suspended? Only reason I ask is I'm hitting it with steel wool/fast orange and I might smooth it down (there is a LOT of carbon in here) in the process.

Plus...is it normal to reach behind the valve seat and actually be able to feel the bump where the seat begins. There is a slight step-up.

Sucks to be a prefectionist

tjm73 · Sep 20, 2005

Yes they are like that as a result of the CNC machine porting them. Smoothing them to a mirror finish won't give you any noticable improvements in power and porting them will likely hurt their already excellent flow carrectoristics.

I would clean them with carb cleaner and wipe out any excess carbon. Making them really clean is an exercise in futility and a waste of time. With in a short time your engine will deposit carbon on the cylinder heads too. Excessive carbon is bad, but some carbon build up is normal.

Wish I had those heads.

crazypete · Sep 20, 2005

Well what bothered me is the lump of oil around the top inside of the intake valve. I am starting to suspect that the engine these were on grenaded. 2 of the valves are brand spanking new while the rest are originals.

I am hoping that by being carbed, the gas running through the motor will keep it clean. I am curious how much buildup I will have when I pop my gt-40p's off after 2K miles.

vristang · Sep 20, 2005

crazypete said:
I am cleaning up a set of 165's to install 200 pounder triple springs. There is a lot of carbon caked in there for a set of heads the SUPPOSEDLY only has 1500 miles in it (how much carbon should 1500 mile heads have in there). Lots of oil sitting on top of the intake valve too (how much is supposed to slip past the seals?)

Anyways... the ports seem to have a regular series of lines (think of a cross section of an onion) from the porting machine I assume. Are these leftovers of the porting process or some form of intentional roughness to keep the mixture suspended? Only reason I ask is I'm hitting it with steel wool/fast orange and I might smooth it down (there is a LOT of carbon in here) in the process.

Plus...is it normal to reach behind the valve seat and actually be able to feel the bump where the seat begins. There is a slight step-up.

Sucks to be a prefectionist

It sounds like the car that these heads came off of had some pcv/blowby issues, as many mustangs do. The oil on the back of the intake valves probably came through the intake manifold, not from the combustion chamber. When I pulled my heads to rebuild (due to low tension rings) they only had about 1500-2000 miles on them, but they looked like million mile heads.

I am not sure which runners have the ridges. The intake ports should be quite smooth. This is where you can make flow gains with mirror polishing. This point is debated, even among professionals, but with fuel injection it should aid airflow. On the exhaust ports, they will carbon up fairly quick, so mirror polishing will do little good unless you will be cleaning them between track events. However, I would think that flow would improve if they were atleast smoothed out.

just my thoughts
jason

crazypete · Sep 20, 2005

Its good to hear that nobody said the lines are for some form of intentional turbulence since I dont think they will be there once I finish cleaning all that crap out of the heads.

Modular2v · Sep 20, 2005

crazypete said:
Its good to hear that nobody said the lines are for some form of intentional turbulence since I dont think they will be there once I finish cleaning all that crap out of the heads.

OMG thats what those lines are for!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

JK lol

hrc1 · Sep 20, 2005

I left the lines in mine. Reason being a buddy of mine who has been professionally porting heads the lst 30 yrs clued me in on something. When he ports a head, he leaves the intake rough, as air will skip over voids and actually drags on a smooth finish. Thats the same reason golfballs are dimpled. A smooth golfball wont travel as far as a dimpled one. Some exotic car companys are using dimpled underbody pans to reduce drag. He polishes the exhaust for one reason, so carbon doesen't build up as bad. It has nothing to grab onto. Ideally the exhaust would be rough as well. taking them out probably wont be noticable except on a dyno.

crazypete · Sep 20, 2005

So am I completely wasting my time cleaning this carbon off?

hrc1 · Sep 20, 2005

I wouldn't say that, i'd clean it off if i had mine off too. It will come back, but at least it's not building up on what was already there. I thought about smoothing the ex ports before i put mine on 2 weeks ago, but i couldn't wait. Maybe next time there off i will polish them. Deffinatly leave the intake rough though.

vristang · Sep 20, 2005

crazypete said:
So am I completely wasting my time cleaning this carbon off?

No.

crazypete · Sep 21, 2005

This current tactic of fast orange plus steel wool then rubbing alcohol is not really working that well. It's taking too long

What could I dip this in that wont eat the aluminium?

I would have to pull the valve seals to dip. Is there any particular trick to installing valve seals? They look like little rubber caps with a metal band. I just slide and crimp, right?

Too many questions, I know but my springs came with new valve seals and what looks like brass washers about as large as the spring diameter. These go....on the bottom to guard the head from the spring or the top to guard the retainer?

tjm73 · Sep 21, 2005

tjm73 said:
I would clean them with carb cleaner and wipe out any excess carbon.

Like I said before....

Carb cleaner is THE solvent for carbon removal. Use it liberally.

jrichker · Sep 21, 2005

The big washers go between the spring and the soft aluminum head. They keep the spring from chewing up the head.

rd · Sep 21, 2005

Intake valves typically build up a deposit of carbon and oil at the valvestem/valve head area. It is from oil coming past the valve stem seals. It would not help flow, and it may be more pronounced in a high performance engine. I was dissappointed to see how my carefully ported heads and 3 angle valve job looked after 70,000 miles.

I would clean it off and press on.

High performance use will most likely cause less than stock oil control, as will valve guide wear, etc. If some valves are much worse, they may have more guide wear, or more seal wear. Make sure to put new valvestem seals in when you redo the heads.

It should not be considered a major problem.

crazypete · Sep 21, 2005

Thanks for the replies guys!

To install those valve stem seals....I just slide them on or do I need to do anything further? I saw there was a "special install tool" for stem seals and I'm was wondering if it does anything I cannot replicate with some clever prying.

AFR165 port question: Is it slightly ridgy on purpose?

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