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| Building the Ultimate 2.8L (Page 4/9) |
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Arns85GT
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MAR 25, 10:30 AM
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NItrous is like a drug, and it will use up an engine if you give it a steady diet.
The turbo will not have that engine looking stock.
Arn
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DarcyJL
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MAR 25, 12:34 PM
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Couple things i want NA and i dont care to look stock just be the original engine..
Its all the big and little things you guys are mentioning that i was looking for and you are all doing a great job. Still need some clarification on the valve float issue. Not sure my decisions on the valve train and cam choice.
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zkhennings
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MAR 25, 01:46 PM
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Hudini tried running 1.6 rockers with 260H cam and he got a lot of noise IIRC. I think there is a good variation in the spring install height in the stock heads. I know that the factory manual says the springs are only good up to around .43 something inches of lift, it is just whatever the exhaust valves lift is stock. I am sure they only say that because they don't want to be liable for anything, but it also means there is no definite answer for what the max valve lift the stock springs are good to. I would definitely go with a really aggressive cam if I were you, some stiff valve springs, full roller rockers, highest compression you can get away with, and do the oiling modifications in the Chevy performance manual for the 60* V6. I think the stock crank is supposed to be relatively strong, at least according to the performance manual. They do reccomend some nicer connecting rods, and I would reccomend ARP rod bolts to deal with the higher revs.
Essentially higher revs and compression is really how you are going to get more power out of this engine, so make it flow better at higher revs (cam, intake (you got this covered), headers) and build the engine to take the added loads (oiling, hardened rod bolts and maybe head studs, valve springs, Full Roller rockers, connecting rods)
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Arns85GT
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MAR 25, 01:59 PM
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I had Scorpion full rollers on my last build and they do not fit under the stock Fiero valvecover. The roller tips do.
Building an engine is kind of an individual thing. I know one guy who built a 2.8 with boost and couldn't hold the tranny.
You really have to think it through and do what you think will deliver the torque curve and power band you want.
If the valve float is a concern, get a set of bee hive springs and have done with it. Simple.
Arn
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lou_dias
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MAR 25, 02:57 PM
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I had my lower intake ported pretty far (and polished) but it looks like in your second link, they went even farther than my machinist:
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lou_dias
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MAR 25, 03:21 PM
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| quote | Originally posted by DarcyJL:
Because we are building the "Ultimate 2.8" not the "Ultimate 3.4" .
I would like to keep my car numbers matching and i dont want to stroke.
NO SWAPS!!!!!
Thanks for the advice but it seems like every thread started about 2.8s turn into the "why wouldnt you threads".
Im not looking for stock look as i have a Falconer ITB Intake.
What parts would build the ultimate 2.8l ???? |
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In that case, nothing is stopping you from over-boring to 3.1L ...
Also, I think it's possible to remove the roller lifter guides from a 3X00 block and use performance roller cam and lifters.
Ignore the comments about NOT using 1.6 rockers, they are stock 1.6 for 3X00 engines, heck the Iron Duke uses 1.7 rockers... Do use a full-roller design though...
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AL87
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MAR 25, 03:49 PM
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| quote | Originally posted by DarcyJL:
Couple things i want NA and i dont care to look stock just be the original engine... Not sure my decisions on the valve train and cam choice. |
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valve float will happen with stock springs around 5500-6000 rpm, no it will not damage anything, but mechanically the springs wont be able to keep up with the motion of the cam, some stiffer springs will solve this if you arent looking to maintain an rpm above 7000 then stock connecting rods are alright.
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AL87
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MAR 25, 03:53 PM
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also keep in mind your valvetrain.
there are four types of rockers
solid flat
solid roller
hydraulic flat
hydraulic roller
the types used in the 60* V6 are all hydraulic.
flats keep the torque up in the lower rpms.
rollers keep the torque in the high rpms.
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Blacktree
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MAR 25, 04:36 PM
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Like mentioned above, stiffer valve springs will combat valve float. You shouldn't need anything exotic, though. For example, the Comp Cams #980 springs should be stiff enough (assuming you don' pick a really radical cam profile). And they can handle around 0.500" of lift.
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Arns85GT
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MAR 25, 05:22 PM
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| quote | Originally posted by AL87:
valve float will happen with stock springs around 5500-6000 rpm, no it will not damage anything, but mechanically the springs wont be able to keep up with the motion of the cam, some stiffer springs will solve this if you arent looking to maintain an rpm above 7000 then stock connecting rods are alright.
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I don't know where you are getting your opinion on this. I have 1.6 rockers and stock springs. It revs reliably to 6,200 rpm and no hint of float. BTW I have driven cars where I could float the valves, and this Fiero is not one of them
Arn
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