I am looking for opinions on the best way to clean (remove paint, carbon, etc.) a set of cylinder heads before I begin to port / polish. I am planning on getting it done professionally (cleaning) and wonder what is the best way. Also, has anyone tried to install larger intake / exhaust valves in our iron heads to gain flow? If so, what size (maybe what donor car valves) were used. I am planning on getting a five-angle valve job (aid flow) and figured this is the best time to up-size if possible.

Shot blasting is best followed ,,by a hot water spray bath there are other combinations you can use ,,before you do this ,, you hot tank,,or clean as well as possible at home ,,soak in gunk engine cleaner ,then hot wash,,use garage in winter(Hmmm,,wonder why Im no longer married?? hot tank is simple cheapest ,plan on checking rust on heads no matter what you do
The gaskets should be removed by carefull scrapping and liquid gasket remover ,,no scars or cuts allowed on head surfaces,,prep before you take to shop..do not use sandpaper on a head surface
never ,NEVER sand blast a block or head,professional cleaning is FAR away best..
you can clean the valve covers & manifolds at home the inside of the ex manifold only needs a real good clean if you are going to ceramic coat inside..
A professional flow bench port job is the best thing to do ,not cheap,,more important than big valves 5 way valve jobs ,,if you do port work remember to leave the shark fins in the ports ..
you can home clean with wire brushes tooth brushes(many of them),bore brushes for assorted holes,, you can not equal the hot tank job but get it clean enough ..
I,ll leave the more interesting valve stuff to those who know more about fiero,s than I ever will
big valves !! 3/5/7 way valve seat cuts are wasted with out a flow bench port job
most machine shops cut to much material out of the valve seats this was my experience when I was a scooter mechanic,, and did not like to use the shop unit we had !!
Rifle bore brushes are really neat for cleaning engines
use chaser tap or bolts to clean out threads ,,only use a regular tap if threads are damaged avoid regular tap for cleaning Q tips can be your friend here ,or soft rags wound into threaded areas to remove rust and crapola..

[This message has been edited by uhlanstan (edited 01-13-2009).]

I'm hoping someone else can provide better info than I, but I was told by two machine shops that it would be relatively worthless for me to go with larger intake valves on my Fiero because the intake plenum and manifold was more restrictive and that the valves weren't the problem.

However, you can improve flow going into them by upgrading to those Fiero Store stainless steel "swirl" valves.



http://www.FieroStore.com

Part #52876
Price:$169.95

I was told that these engines benefit from going with a SLIGHTLY larger exhaust valve.

But, I didn't end up doing it, so I can't say for sure...

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Todd,
2006 Pontiac Solstice
2004 Volkswagen Beetle Convt. (Wife's)
2002 Ford Crown Victoria LX
1987 Pontiac Fiero SE / V6
1981 EZ-GO Xi875-A "Miami Dolphins" Medical Cart
1973 Volkswagen Type-2 Transporter
1973 Oldsmobile Cutlass Supreme 350

for valves I found making custom valves to be a reasonable option. 1.78" intake and 1.50" exhaust. Both flat-top, saving 3cc, helping to bump compression. I think these are the largest you can reasonably fit in the Fiero head.

daveg

quote Originally posted by 82-T/A [At Work]: I'm hoping someone else can provide better info than I, but I was told by two machine shops that it would be relatively worthless for me to go with larger intake valves on my Fiero because the intake plenum and manifold was more restrictive and that the valves weren't the problem. However, you can improve flow going into them by upgrading to those Fiero Store stainless steel "swirl" valves. http://www.FieroStore.com Part #52876 Price:$169.95 I was told that these engines benefit from going with a SLIGHTLY larger exhaust valve. But, I didn't end up doing it, so I can't say for sure...

while this is true - some people have improved or removed the plenums, and ported the intake manifolds.
larger valves is ALWAYS a good option, if you can do it. even if you have the stock intakes - it will increase low end power.

I did not want to post on larger valves because I think it is a bad idea unless you are building racing engine ,,I have never rebuilt or worked on the inside of a V6 fiero but I have many years building motorcycle engines..Pyrithian & 82TA have good info .. I would just go with the stock size performance valve,s from the fiero store ,,make sure you check the head carefully for cracks,BEFORE you do any performance work especially in the valve seat area ,,invest in a chemical kit so you can see the flaws,,20 year old heads are not good candidates for larger valves,,
The few fiero heads I have looked at (including my 2 spares awaiting porting and magic spell) could be cleaned easily at home with gunk ,oven cleaner,carbon remover, and elbow grease ..
The flow bench is the key to best performance ,then open exhaust ,,port match,, then intake clean up including radius TBI opening
A performance engine starts with a balanced crankshaft,,took years for this to enter my thick skull ,, I had a Harley engine crank electronically balanced !! WOW,, what a difference

[This message has been edited by uhlanstan (edited 01-14-2009).]

More great information.....keep it coming. I have done lots of cylinder head work in the past (porting, polishing, chamber cc-matching, etc.) but when I got the stuff it was already clean, so all this info helps. I am well-versed in matching the rest of the system (heads, intake, cams, balancing, ignition, etc.) as I used to (8-10 years ago) build some pretty strong and reliable circle-track engines for a few local guys. I am just new to the V6 arena (shouldn't be much of a change) and getting my feet wet again. Just gathering information from people who might have tried this first.

Bob

the fieros store valves are loarder than stock, or I got an off set, as we had to open up the seats quite a bit to fit em in.
The tulip design and swirl types make a big improvement over stock valves.
As for cleaning the head, your shop will tank em and boil em out, you won;t really do any better than that.



That;s 150k mile heads boiled with the SS valves. if you look at the one on the block you can see the blueing still slightly visible on the intake ports from the porting/gasket match. it is also slightly visible on the head from the valve work. As you can see form the middle one which is pretty dead on, there is not much room to go bigger with valves.
Now re they worth that money? I can;t say, but my motor is precision balanced, and I have no issues running it past the 6k readline on a regular basis. I also don;t seem to see that "wall" at 4k that everyone complains about, unless I have the cat installed.

Thanks Tjm. Those are great pics! It is strange that the left-hand chamber seems to have quite a bit of room between the valves (optical delusion?) than the center one. Did your machinist ever recommend to cut back the chamber walls next to the exhaust and intake valves (unshrouding) to help improve breathing, especially during the initial low valve lift? It does increase chamber size somewhat, but if the chambers are cc-matched to the largest one and then the heads slightly shaved to bring back down the volume (usually a minor cut) it does aid in breathing and power/compression balance between cylinders. Just a thought.

yeah I think its an opticla delusion due to the closeness and angle.
The valve pockets are full opened, no shrouding. the heads were just clean up milled, as they had been cleanup milled previously, and thoser are the higher comp 9.5 pistons, so I didn;t want to go anymore.
this guy was very accomodating, after he boied me, he removed the valves etc, he called me to pick them up to port em up, so I sepnt a few days removing about a pund or 2 of cast and brought them back. then he discovered the new valves were bigger, so he readjusted the chambers accordingly at no charge. I doubt without extreme tweaking you could flow much more than these heads.
my bext area of gain will be the plenums, but it does rather well for a lowly 2.8, in part due to the extra rpms.

quote Originally posted by tjm4fun: yeah I think its an opticla delusion due to the closeness and angle. The valve pockets are full opened, no shrouding. the heads were just clean up milled, as they had been cleanup milled previously, and thoser are the higher comp 9.5 pistons, so I didn;t want to go anymore. this guy was very accomodating, after he boied me, he removed the valves etc, he called me to pick them up to port em up, so I sepnt a few days removing about a pund or 2 of cast and brought them back. then he discovered the new valves were bigger, so he readjusted the chambers accordingly at no charge. I doubt without extreme tweaking you could flow much more than these heads. my bext area of gain will be the plenums, but it does rather well for a lowly 2.8, in part due to the extra rpms.

um those heads do have valve shrouding. I can see it is not opened up. and the combustion chambers were not even touched on the port/polish job.

The Fiero allready has larger valves than a reg iron head. Not too much room for bigger.

And larger valves would help on top end not bottom end. FYI

oh and the first ? a hot tank would be the best, Not too much left after that, just minor paint(very minor) (if they were painted before)

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"DRIVE IT LIKE A FIERO"
'84 Fiero, engine to be determined
'87Blue GT 3.4L Swap Completed!!!!!!!! Boosted!!!!!!!
Las Vegas Fiero Club
Fiero Road Club Of Northern Nevada

[This message has been edited by sardonyx247 (edited 01-16-2009).]