In the little time I have left in my deployment (YEAH!!!) I'm creating an engine specs calculator to compare and contrast proposed changes to either my 2.8L or a 3.4L pushrod engine I'm thinking of building up or swapping for my 88 Formula.

Before I get the usual "Do a search of the archives" or "check out http://60degreev6.com" understand that I already have, quite extensively. What I'm looking for are no kidding confirmations of the stock specs for both of these engines. In my searches I've either found differing information, missing information or specs that I just frankly can't believe. Since I've never been into the internals of my engine personally I may have to "believe" some of the specs if folks on PFF with more experience can back them up.

For the calculator what I'm intrested in are the following specs:
Bore (in or mm)
Stroke (in or mm)
Deck Height (in or mm)
Gasket Bore (in or mm)
Compressed Gasket Thickness (in or mm)
Piston Dish/Dome (cc)
Head chamber volume (cc)

This is what I already have for the 2.8L:
Bore 89.0mm
Stroke 76.0mm
Deck Height 224mm (which is one of the specs I just can't believe)

The specs I'm assuming until I can find or get the info for are:
Gasket Bore (I'm assuming 89.0mm for now)
Piston Dome/Dish (assuming 0.0 cc for a flat piston)
Head Chamber Volume 52.0cc (I've also seen 56cc on the forum)

And for the 3.4L:
Bore 92.0mm
Stroke 84.0mm
Deck Height 224mm (which I still just cannot believe is correct)

Again assuming:
Gasket Bore (assuming 92.0mm)
Piston Dome/Dish (assuming 0.0cc for a flat piston again)
Head Chamber Volume 52.0cc (Assuming I use the 2.8L Fiero Iron heads if the 2.8L spec above is correct)

What I need is;
A confirmed deck height 224mm... that seems waaaaay too large for a deck height to me,
The Compressed Gasket Thickness (haven't found anything)
The Iron heads actual volume in cc's
A confirmation of my assumptions posted above... ie the Gasket Bore being the same as the cylinders etc.

So what I've created is (thus far) just an engine displacement and compression ratio calculator so I can see what if any changes I want to make to either my current 2.8L or a proposed 3.4L swap. So far it's worked using the numbers from a 350 SBC example pulled from a Car Craft article explaining how certain changes increase or decrease compression ratio etc. So just a few more tweaks and the raw data from our engines will help me to finalize it... then if the outputs match the known compression ratio and volumes for our 2.8L's I can see how an overbore, stroker, change in gasket etc will affect both displacement and CR at the same time.

Ultimately I'd like to add in an calc to estimate HP, torque etc... depending on my understanding of the math behind them (self taught auto engineering haha)

It also has a wheel calculator since the offsets in the '88 are odd, but thats a different story/thread.

Thanks PFF for any help finishing this up!

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Four Fans of Freedom
"Fiero Fugit"

quote Originally posted by Leeloo88: This is what I already have for the 2.8L: Bore 89.0mm Stroke 76.0mm Deck Height 224mm (which is one of the specs I just can't believe) [...] And for the 3.4L: Bore 92.0mm Stroke 84.0mm Deck Height 224mm (which I still just cannot believe is correct)

I have no experience with these engines, but why deck height 224mm (as I understood - distance from centerline of crankshaft to top of block, more or less) sounds unbelievable for you??? It looks typical for me.

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Fiero 1985 notch 2.5 automatic
http://boni.smutek.pl/auto

[This message has been edited by Boni (edited 01-02-2011).]

ooops, I misquoted the measurement name, should read Piston-Deck Height.

http://www.carcraft.com/tec...ion_ratio/index.html

Look at the section under Clearance Volume, thats the measurement I need to calc up. Obviously zero decking the engine would make that calc go away but since I want the baseline to confirm the known #'s it needs to be taken into account. So whatever the actual name is I need the Piston @ TDC to Deck distance. On the SBC example it ran from "0.003 to 0.020 inch" per the article. If the spec I pulled from 60degreev6.com is the same measurement (which I don't think it is) then a 224mm from the Piston @ TDC to the Deck would be unbelievable at 22.4cm.

Sorry for the confusion the actual spec I need is the one from the top of the cylinder to the deck.

Thanks

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Four Fans of Freedom
"Fiero Fugit"

quote Originally posted by Leeloo88: This is what I already have for the 2.8L: Bore 89.0mm Stroke 76.0mm And for the 3.4L: Bore 92.0mm Stroke 84.0mm

The bore and stroke numbers you have for the pushrod 2.8L and 3.4L 60^o V6 engines are A-OK.

Regarding the heads...
The 2.8 and 3.4 iron heads are identical. They're the same casting and same valve size. Completely interchangeable.
The only difference is in the early carbureted 2.8 heads. They have smaller valves. (I believe the X11 had big valves, even though it had a carb, but they were in the minority.)

You didn't ask about cams, but the 2.8 Fiero cam and the 3.4 Camarobird cam have identical specs. The only difference is that the 3.4 casting has been modified to trigger a cam sensor.

When you went to 60DegreeV6.com did you check out the CR Calculator? It seems to have all the numbers you are looking for but in inches instead of mm. For instance it shows a Piston Deck Clearance of .026" for the 2.8L HO engine (Fiero version).

http://60degreev6.com/conte...008254da9eab143e4a2c

According to Fel-Pro's published specs, compressed gasket thickness for the Fel-Pro head gaskets is 0.039", and bore size is 92mm.

I also remember the deck height figure being significantly different from the actual measurement from my engine. Unfortunately, I didn't record any of that stuff when I rebuilt the old 2.8. To get optimum quench height with the Fel-Pro head gaskets, the pistons should be almost flush with the deck (optimum quench height is 0.040").

BTW, the chambers in my old 2.8 heads measured around 51-52cc each. I think the published spec is 52cc. After I shaved 0.010" off the heads, and CC'ed the chambers, they were around 50cc each.

One more note: The pistons in 2.8 V6 engines with 8.9:1 compression ratio will have flat tops (i.e. no dish). I think some had a slight dish, which yielded an 8.5:1 compression ratio.

[This message has been edited by Blacktree (edited 01-02-2011).]

quote Originally posted by Blacktree: One more note: The pistons in 2.8 V6 engines with 8.9:1 compression ratio will have flat tops (i.e. no dish). I think some had a slight dish, which yielded an 8.5:1 compression ratio.

Somewhat more specifically, the standard production 2.8L V6 engine (which the Fiero did not have) came with 8.5:1 compression.

However, the 2.8L V6 engine in a Fiero came with 8.9:1 compression.

This is definately good stuff... especially with Hudini pulling the "rabbit" out of the hat with that CR calculator... I've seen plenty of calculators for CR online and thought I was familiar with 60degreev6 website but I must've missed that particular gem. It'll help verify the one I'm making myself as well as be a source for some of those numbers I was looking for.

Really all this is, is an exercise in mathmatical modeling/engineering to learn more about the internals of engines... as well as burn some time until I get to board my plane home. Since this will be my first teardown/rebuild or swap of any kind... it just helps me to understand what's going on under the hood, and how any changes affect it all. The hope being that ultimately it might lead to a bad@$$ 3.4 that I can enjoy and that others might be able to benefit from.

So if I'm understanding you Raydar the heads are identical between the ones built in 84-88 for the Fiero 2.8HO L44 and the ones built in 93-95 for the Camaros 3.4 L32... as well as the camshafts between the two.
So far the focus is in the block/heads without camshafts playing into it yet but if all goes well with this initial model I will be getting into camshafts later. I've got the basic idea of how they work down but many details are still quite confusing.

Blacktree... what can I say... Thanks, are you just pulling that info out of the federal-mogul webpage? I was looking in there and got more general info... sales jargon really, nothing you'd call "hard data".

I was just assembling a 3.2 - my old 2.8 block, and a 3.4 LQ1 crank I had laying around. For what it;s worth, here are the actual measured numbers I came up with:

Block was bored 0.040, pistons were P1592. Assembled, the pistons were .022 to .031 in the hole, using the #1 piston and rod on at 4 corners. I decked the block about .026, both sides, referenced from the main bore fore and aft, but from the existing deck side to side. (I was doing this on a Bridgeport clone at home.) Assembled,checking the deck, 4 holes were between 0.000 and plus 0.004, two were about plus 0.015. Quick calculation on the weight to be removed, figured it would be OK, and cut the tops of the pistons on the two offenders. Deck on all of them is now 0.00 to 0.004.

Felpro head gasket - 8699PT2, the normal gasket, couldn't find specs either. Gasket bore measured at 3.653. Thickness measured 0.058 off the engine, I installed and torqued, and found a space at one end between the head and the deck where I could get a feeler guage in - installed thickness is 0.050. Piston dish measured at 10.5 cc. The heads were already valve-jobbed and surfaced when I got them, I don't know how much was taken off, probably just cleaned up. Chambers averaged about 50cc. This gives a CR of about 8.75. If I knock the chamber volume down to about 45cc, that will give me about 9.35 CR, about where I would like to be. To get there will take about 0.035 milled from the heads. I will check piston/valve clearance, but not really worried, with the .105 dish in the pistons. So the total stock removal is about 0.060 between the heads and the block. I could have gone for a shim head gasket instead of cutting one or the other, but buying parts cost money, cutting off metal is pretty well free - in the DIY mode. I will probably need to use lash caps on the valves - easier/cheaper than custom length pushrods.

Hope this helps,

Mike