Well the manifold bolt extraction did not go well and the heads have to come off to get the snapped bolts out. I figure, while they are off, I might as well have the heads ported. This is "greenhorn" territory for me. What type of specs should the heads on the 2.8L be ported to? What should I expect (generally) to pay for this? Any advice and opinions are going to be very helpful as this is going to be worked on tomorrow (the 26th).
Thanks!
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07:26 PM
PFF
System Bot
82-T/A [At Work] Member
Posts: 25014 From: Florida USA Registered: Aug 2002
Well the manifold bolt extraction did not go well and the heads have to come off to get the snapped bolts out. I figure, while they are off, I might as well have the heads ported. This is "greenhorn" territory for me. What type of specs should the heads on the 2.8L be ported to? What should I expect (generally) to pay for this? Any advice and opinions are going to be very helpful as this is going to be worked on tomorrow (the 26th).
Thanks!
You don't want to do TOO much porting because it will increase the CC chambers and reduce your compression. Really, your goal should be to remove restriction and improve flow in and out of the combustion chamber. There are specific rules that apply to this... and I'm just going totally from memory:
You'll want to have the intake ports "port-matched". To be honest, it's actually BEST to do this before the cyl head gets machined and cleaned. The reason for this is because the EGR system on our Fieros likes to deposit soot on the entire intake passage... what this means is... everywhere you see black soot around the intake port, that's where the restriction is. You'll want to grind that way.
As for the exhaust ports... you can smooth them out, but in most engines, it's best to leave the exhaust port "floor" alone, and not touch it one bit.
You can clean up the area around the valve stem inside the intake port as well... you can make that a mirror finish.
In the past, they would say NOT to do this because the fuel hasn't properly atomized, but that really applies more to carburetors which don't have as clean of a spray as our pintle style fuel injectors do.
As for the combustion chamber... you can round-off the ridge that's around the valve shroud. NOTE, I am NOT talking about the circumfrence of the combustion chamber. That's about it really... hopefully someone else can add a bit more to my general advice.
Head porting gains all exist inside the bowl only. I'd do light porting but NO POLISHING in any of the runners. Leave3 the floor alone, and dont take out the fin. Port matching has far fewer gains than opening up the bowl behind the valves, This is the most difficult part because if you even nick the valve seats, you gotta get a full valve job done.
I'd get the scotchbrite Cross pads to run through all the ports to clean them out no matter what. sandpaper flap cones and wheels work the best for beginners porting. if you portmatch the intake side, you gotta portmatch all the intake pieces as well. Going nuts and hogging them all out wide gives you almost no gains.
go lightly, practice on a trash head first. you will be surprised how insanely easy it is to ruin a valve seat when porting the bowl.
Really....Ive never heard of not polishing when doing the porting. Yeah I have seen people say do the manifold matching port job, and others say that if you merely do that, you'll gain nothing and best just to leave it alone. Rather confusing anyone know which is truly the best way to go and what a machine shop should charge to do something like that? Also, has anyone ever used the TFS "performance" heads and do they do anything for $650?
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10:03 PM
Jan 26th, 2009
Blacktree Member
Posts: 20770 From: Central Florida Registered: Dec 2001
The Fiero Store "performance" heads are nothing special. They're just a set of heads with a good refurbishing. There's no port work or anything like that. You can have a local shop do the same stuff for half the price, or less.
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12:31 AM
tjm4fun Member
Posts: 3781 From: Long Island, NY USA Registered: Feb 2006
For the 2.8, gasket match the intake and exhaust ports, smooth the stipple off the fin and intake passages and go to town in the bowls, there is alot of extra metal in there and it is like a dam to airflow... well at least mine were.. put some heavy cloth tape over your valve seats to protect them. with a clean valve pocket, and smooth surface on both intake and exhaust, that;s all you can do for a stock motor. doing the fixes on the exhaust logs will likely buy you far more than the headwork, take a look in the rear 2 ports and you'll see what I mean. Polishing is fine for race motors. does nothing for a street motor, especially a stock one. Smooth is probably over doing it, but I do like smooth, flowing surfaces.port and gasket matches help there, as any abrupt change in passage area will create a turbulance that impedes flow. That theory aside, you will find LOTS of extra casting blobs to clean out (NOT THE FINS THO!!!). I think I ended up with about 2 lbs of cast iron from each head when I did it. I use a rotary file, also called burrs in an old drill, if you don;lt have a lower speed electric die grinder. actually, that;s all I use, I have never needed to use a stone or sandpaper, the burr will leave a nice enough finish.
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03:50 AM
Oreif Member
Posts: 16460 From: Schaumburg, IL Registered: Jan 2000
Call around to shops if you do not want to tackle the job yourself. A local shop by me did both heads for $350. They tank cleaned, 5-angle valve job, ported, polished, and decked (shaved .010) the heads then installed all new springs, seals, locks to match my new cam. The only parts I had to buy and supply was the SS valves. They would have done the valve job with the stock valves, But I opted to use the SS valves.
------------------ Happiness isn't around the corner... Happiness IS the corner. ZZ4 Powered !!
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07:28 AM
Dennis LaGrua Member
Posts: 15761 From: Hillsborough, NJ U.S.A. Registered: May 2000
My experience has proven that an engine swap is most often the less expensive route to horsepower than pouring tons of money into the 2.8L. Compare what you will spend for the horsepower gained, then price a good used 3800 N/A or 3.4L engine. You can buy these complete engines for few hundred and with very minimal mods have 200HP with rock solid reliability. Both are not difficult swaps with the manual trans. You'd have to spend far more to make 200HP from a 2.8L and I don't even know if anyone has ever done it without adding a turbo. The 2.8L breathes poorly, port the heads and you'll need to improve the plenum, TB, exhaust manifolds and so forth.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite. 87GT - 3.4L Turbocharged engine, modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
You may as well have a little shaved off the heads to bump the compression up along with the port work while you're at it and maybe a little off the intake manifold port surface to make sure you have proper fit at the heads afterwards. This will at least insure that you get the most out of the stock parts without a cam upgrade. I believe the two combined will result in a difference you can feel.
I've read that the reason you don't want to completely smooth the intake port is because the rough surface helps with fuel atomization. I'm just not sure if that's an old rule associated with carbuerators that has been applied to fuel injection since the injector being a little closer to the intake valve and spraying fuel under pressure already suggests good atomization. I wonder if GM increased the fuel pressure from the early FI ~47 psi to the current ~56 psi for the added benefit of better fuel atomization.
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05:15 PM
sleebbie Member
Posts: 173 From: Caldwell, NJ, USA Registered: Dec 2008
Well I am adding the sprint headers. Unfortunately I dont have a manual trans, but i also kinda wanted to keep my Formula stock looking and not swap out for a different engine,just make the best that I can with what is there. Still waiting for a port estimate from my guy, but I may have to shop that around. I was going to go ahead and do a big bore TB and eventually bore the plenum and Y-Pipe.
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07:50 PM
Francis T Member
Posts: 6620 From: spotsylvania va. usa Registered: Oct 2003
I would suggest you just have then refurbed with the addition of a 5 angle valve job, have the spring heights checked, new retainers and keepers, new valve guides and a good cleaning - oil passages and all- etc. If you're putting a hotter cam in, get hi-pro springs and lifters. BTW: the stock are not near as bad as a lot people think. They can flow more than enough CFM even with modified engines.
I was thinking about porting and polishing my extra set of heads, and offering them up for sale. What would be a good price for them. (This sounded like a good thread for it) Most shops don't even want to do porting anymore, as they have got sick of the iron dust. Or at least what a few told me.
I would just stick to the standard, leave the intake rough, and the chamber and exhaust mirror polish.
The V6 heads should be ONLY lightly ported unless you pay to flow bench them ..All those who have advised you know more than I ever will about the fiero V6..but I have years of building motors and motor bike race engines ,,I have a set of V6 heads awaiting porting.. Go light on the port job ,,.unless you can afford flow bench port... Port match is ALWAYS a good idea. the sprints will work well if you also port the Y pipe or buy one of the performance Y pipes ,if Trueleo has this ,,go with that option,,The fins are there for a good reason..use cherry bomb or some other less restrictive muffler ..
I would not go with the opened up throttle body unless you port the intake ,of course this is your decision and it sounds good ,,has any one added the performance throttle body with out open up the manifold if so what was result ?? I would not spend a lot of money on porting the heads unless it was with a highly regarded shop,,your best option may be to buy from a forum member who ports for you Before you buy manifod gaskets make sure sprints line up good with Y pipe if Y pipe is wide use fel pro if it is tight use VW gaskets(Im learning about this) ..it is easy to mess up a set of heads with aggressive porting,,clean it up . Engine swaps are complicated and a lot of work ,, the V 6 can be made to deliver more MPG & a HP increase ,,I would take it easy tho don,t go to aggressive ..Read the info and make your own choice..do not forget to come back and let us know how you progress. the depth of the head exhaust ports threads to hold the exhaust flange to the head is about 18cm ,,make sure the bolts do not bottom out
[This message has been edited by uhlanstan (edited 11-03-2009).]
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08:57 PM
sardonyx247 Member
Posts: 5032 From: Nevada, USA Registered: Jun 2003
Pics of my heads after porting, the bad pics don't do it justice. And don't worry about the lines on the intake ports, they line up with the gaskets I have on it now.
quote
Originally posted by sardonyx247:
My ported and polished heads, with a 4 angle valve job. I ported the intakes, and a mirror polish on the exhaust ports and combustion chambers.
Red GT 1988 Auto 50000 miles. Darell Morses oversized Throttle body. Upper intake plenum ported and matched. Middle intake ported & matched. Lower intake ported & matched. Heads Ported and matched. Performance valve springs, retainers and keepers. Heads milled to accomplish right Installed Spring Height. 1.6 roller rockers, new nuts and spacers. New valves. New Valve seals. Valve Seats polished. Lapped. New pushrods. Lifters overhauled. Exhaust manifolds TIG welded and ported. Y-Pipe Ported and TIG welded. Header wrapping Manifolds and Y-Pipe. Removed Catalytic converter, Straight pipe in place. Splitfire plugs. Koni adjustable shocks. Fiero Store lowering springs 1" . All rubber changed to Prothane Poly bushings. Prothane swaybar bushings and rods all around. Australian Stage 2 sidescoops, formerly used the original Holley scoop on left side. Water separator modified to gain air pressure from the sidescoop och the left side. K&N Air filter. Removed cat. MSD HEI Ignition coil. Fiero Store Power Pulley. Mikael Normans Dogbone. Hose engine heater for winter driving. Kosei RT Penta Rims 16x7 " Tires Good year: 215/55/16 front 225/50/16 rear Sound system by Ljud på ˆjul. Jensen 2x150 W Amp. with crossover sub connection. Autostudio speakers: 8" Sub in custom made box, fits well to the left of the center console on the passenger side. 2x4" Woofers 2x1" Tweeters Separation filtering on smaller speakers Original stereo and rear speakers Paintjob on Wing, reinforced wingstantions, sidescoops and front. H4-converted mainlights.
[This message has been edited by kjelle69 (edited 01-28-2009).]
Originally posted by Dennis LaGrua: ...price a good used 3800 N/A or 3.4L engine. You can buy these complete engines for few hundred and with very minimal mods have 200HP with rock solid reliability. Both are not difficult swaps with the manual trans.
quote
Originally posted by sleebbie: Unfortunately I dont have a manual trans, but i also kinda wanted to keep my Formula stock looking and not swap out for a different engine,just make the best that I can with what is there.
sleebbie, a few points probably should be clarified for you here.
There's no reason you need a manual transmission for a pushrod 3.4L engine swap. An automatic also works fine and easily with that swap. I know. I have one.
Given the desire you've expressed to keep your Formula "stock-looking," the pushrod 3.4L engine swap fits that bill perfectly.
A pushrod 3.4L V6 engine has roughly 20% more displacement than a pushrod 2.8L V6 engine. However, when installed in your Fiero, a pushrod 3.4L engine looks very much like a pushrod 2.8L engine.
That roughly 20% increase in engine displacement gained with a 3.4L is attributable solely to two internal differences: a larger bore and a longer stroke than in the 2.8L. The external dimensions of the engines aren't 20% different; they're essentially the same. Most won't even know just by looking at it that you had a pushrod 3.4L engine in your Fiero instead of the stock 2.8L Fiero engine. In fact, with the typical 3.4L swap, you basically transfer the externals such as the intake manifold with the "Fiero"name on it, and even the Fiero's valve covers, from the the stock Fiero 2.8L engine to the 3.4L engine. That, I think, is about as "stock-looking" as "stock-looking" gets, is it not?
Yes, it's still an engine swap, albeit about the most stock-looking and easiest one there is. Perhaps more importantly, if you don't want to do a 3.4L engine swap now, you can always later transfer easily to a pushrod 3.4L engine from your current Fiero 2.8L engine your modified cylinder heads, and your Sprint headers (just as I later did easily with mine).
In any case, regardless of what you end up doing, good luck with your project!
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08:36 PM
sleebbie Member
Posts: 173 From: Caldwell, NJ, USA Registered: Dec 2008
Wow that's some of the best info I've heard about a 2.8L to 3.4L swap. I had no idea you could swap over the headers, manifold, headers, etc. That's great cos I am not going to do that swap at the moment, but it is something for the future. In addition, that means that I can buy some performance parts and then swap them over later. I do like the stock look of the 2.8L but I also know that you can sink easily $5-$6k into it and not have the h.p. that you'd get from the 3.4L stock. Now....do things like Hypertech chips and such work with the 3.4L or would things like that be only for the 2.8L and do they really matter than much anyway. Thisd was great info thanks!
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08:49 PM
sleebbie Member
Posts: 173 From: Caldwell, NJ, USA Registered: Dec 2008
While searching for something else, I ran across this unanswered question of yours from an earlier thread:
quote
Originally posted by sleebbie:
Now....do things like Hypertech chips and such work with the 3.4L or would things like that be only for the 2.8L and do they really matter than much anyway.
Technically speaking, yes, Hypertech chips will "work with the 3.4L." However, the much more important thing to know is that Hypertech chips are as much a waste of money on a 3.4L engine swap as they are on your Fiero's original 2.8L engine.
Your much better investment here --- after you've completed your 3.4L engine swap --- may be to get a new chip from http://www.gmtuners.com..
I've not yet found a new computer chip necessary with my own, year-round, daily driver, 3.4L engine swap that is subjected to some truly gawdawful winter weather conditions, but I expect I might benefit from it.
Good luck to you with your upcoming 3.4L engine swap project, but no, I strongly recommend not spending money on a new computer chip, at least not until after you've completed the 3.4L engine swap, and then, IMHO, get one from gmtuners rather than from Hypertech.
My .02 on head work: If it isn't done with flow bench CFM verification it's a complete waste of time and money. You're likely to make things worse (or no change at all) by jacking with port shapes without any way to confirm any improvement. If you do decide to start cutting, don't touch that fin! GM spent a lot of time developing the flow on these heads and put that fin there for a reason.
You'll get the best bang for your buck by doing a quality valve job and cleaning out the stock exhaust manifolds.
To be fair Jazzman, porting the exhaust manifolds is about a 6 hp gain and when I ported the heads, of course with a lot more cfm from the carb, the hp bounced up from 107 hp at the wheels to 132 hp from 4,000 rpm to 6,000 rpm. This is a net 25 hp gain and likely 30 hp at the flywheel.
Arn
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10:44 AM
Jun 4th, 2009
sheppard00 Member
Posts: 193 From: Denison Texas Registered: Jan 2004
look for a good shop that builds racing engines local to your for your head work. Every engine shop should know a good Head man that they trust and use to do thier portwork. I've seen a lot of people spend $ on some ported heads that were poorly done. there is a lot more to porting then making the runers biger. it's a lot about the aproach to the seat and all of the transitions in ther runner. size is'nt even half of the portwork. find someone you can trust, and is well known.
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01:23 AM
Intel Member
Posts: 752 From: Helsingborg, Sweden Registered: May 2002
Just a quick question not to hijack the thread.... are the 93-95 camarobird 3.4L heads the same as the fiero 2.8? I have a spare set of heads from my old 2.8 that are going to be tanked, ported, decked, and a 5 angle valve job.
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05:03 AM
Oreif Member
Posts: 16460 From: Schaumburg, IL Registered: Jan 2000
Just a quick question not to hijack the thread.... are the 93-95 camarobird 3.4L heads the same as the fiero 2.8? I have a spare set of heads from my old 2.8 that are going to be tanked, ported, decked, and a 5 angle valve job.
Yes they are the exact same heads.
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07:19 AM
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
if you have a dremel tool, you can do this. gasket matching the intake is a great first step. as mentioned above, using the "soot line" as a guide is good. in the exhaust ports, you will feel a bump from the spark plug - feel free to remove that. if you are bold enough to go for it - remove the valves, and do some bowl work. THIS is where you find power. a small increase in the overall diameter means ALOT. but, you must also be careful here NOT to damage the valve seat. I wrapped the chuck of my dremel in duct tape just to be sure you can also shape the valve guide some. like the nose of a ship. dont cut any closer than 1/16" to the valve guide hole.
and - be consistant. and, as mentioned - leave the "shark fin". feel free to shape & smooth it - again, like the nose of a boat.
polishing is a 2nd aspect to this. polishing is smoothing the combustion area. not highly recommended, unless you plan on boost or high compression. and, for smooth running - MUST be done evenly. CC'ing the areas, to be sure each combustion area is the exact same displacement. not an easy task for DIY. and polishing the passages is preferance. some say do it, some say dont. the reason to do it: smooth walls flow better, and, of course - looks great. reason not to: small imperfections create slight turbulance, which prevents condensation of the fuel/air mix - this is more a concern for carburated motors.
