1.4L Teardown/Modification
- Thread starter Preloader
- Start date
rdss
Junior Member
Exactly. Unless your parts are being reworked you should put things back in their correct positions. The work Derp is looking at is valve jobs, rod and pistons swaps, etc.... Heavy mod work, he's going to be putting an essentially brand new motor back together when he's done.
Preloader
The M32 Martyr
Stiffer springs, and a 3 angle valve cut. Possibly larger valves, I'll have to consult my machine shop guy to see if it will be worth it or necessary to make 300hp.
Rods and pistons will be later. My first round will be headwork and maximum hp with 25psi or less boost.
Round two will be stronger rods, stronger lower CR pistons and 30+psi boost.
I hope to have round one accomplished by September.
Rods and pistons will be later. My first round will be headwork and maximum hp with 25psi or less boost.
Round two will be stronger rods, stronger lower CR pistons and 30+psi boost.
I hope to have round one accomplished by September.
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sx sonic
New member
Keep everything in order! Take a 2x6 and drill valve stem sized holes for the valves and number and put the springs on the valve (or put dowels in front of the valve for the springs) and an egg carton to match up the retainers and rockers..... or whatever else and number it all. RDSS stated why. do the same for piston, rings, rods, cir clips, small end bearings, etc.
+1 for knife edging the crank, I think it's worth 10-20hp on a 350ci chevy in the upper rev range, so it's something to consider especially if you're upping the revs. If you wanna go fancy you could have the counterweights knife edged AND cut down and filled with tungsten (or something HEAVY) to cut windage further and bring the center off mass in closer to the centerline of the crank; this makes changes of momentum easier.
Another thing to keep in mind about porting is your biggest restriction isn't coming into the head! from about the valve stem onward the air is battling worse and worse flow restrictions, opening the biggest spot of the port doesnt do much when the remaining inch decreases volume by 30% (or whatever) and makes a bend while being obstructed by a valve. You must look DEEPER into the port, pun intended.
Also don't forget about shot peening, radiusing edges, and smoothing over casting marks on the block and particularly components that rotate. As long as their not done wrong all of them will increase strength by removing stress risers.
+1 for knife edging the crank, I think it's worth 10-20hp on a 350ci chevy in the upper rev range, so it's something to consider especially if you're upping the revs. If you wanna go fancy you could have the counterweights knife edged AND cut down and filled with tungsten (or something HEAVY) to cut windage further and bring the center off mass in closer to the centerline of the crank; this makes changes of momentum easier.
Another thing to keep in mind about porting is your biggest restriction isn't coming into the head! from about the valve stem onward the air is battling worse and worse flow restrictions, opening the biggest spot of the port doesnt do much when the remaining inch decreases volume by 30% (or whatever) and makes a bend while being obstructed by a valve. You must look DEEPER into the port, pun intended
.Also don't forget about shot peening, radiusing edges, and smoothing over casting marks on the block and particularly components that rotate. As long as their not done wrong all of them will increase strength by removing stress risers.
Preloader
The M32 Martyr
That sounds extreme.......ly awesome.
But if I'm ever gonna get this project moving, I'll have to prioritize my efforts. My plan has become three-fold.
First, getting a better flowing turbo installed and dialed in.
Second, fully modifying the head and swapping it in.
Third, building up a bottom end for the final stage. Operation: balls to the walls.
Right now I'm really focused on turbo selection. I think I may skip over the GT25 and go right for a 28. The obstacle now is selecting the right trim choice.
But if I'm ever gonna get this project moving, I'll have to prioritize my efforts. My plan has become three-fold.
First, getting a better flowing turbo installed and dialed in.
Second, fully modifying the head and swapping it in.
Third, building up a bottom end for the final stage. Operation: balls to the walls.
Right now I'm really focused on turbo selection. I think I may skip over the GT25 and go right for a 28. The obstacle now is selecting the right trim choice.
Building the bottom end does not produce instant gratification. Working in his order, he will see gains along each step of the way.
I believe there is the added advantage that he can swap parts onto his current engine for stages 1 and 2, while stage 3 is much more in depth.
I believe there is the added advantage that he can swap parts onto his current engine for stages 1 and 2, while stage 3 is much more in depth.
NewZJ
I Don't Know
True, I hope the bottom end doesn't break before it can be strengthened. I'm really interested in what Preloader can do with this motor.
NewZJ
I Don't Know
Forgive my ignorance, I mean no offense. I'm learning a lot here.
Wouldn't just the turbo be difficult enough to dial in that the head modifications wouldn't really make much of a calculation difference since you are changing the factor involving most of the parameters?
Does the engine block/crank/rods/pistons upgrading require a lot of tuning alteration?
Much of my knowledge is assumed and the rest only applies to completely different motors.
Wouldn't just the turbo be difficult enough to dial in that the head modifications wouldn't really make much of a calculation difference since you are changing the factor involving most of the parameters?
Does the engine block/crank/rods/pistons upgrading require a lot of tuning alteration?
Much of my knowledge is assumed and the rest only applies to completely different motors.
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Preloader
The M32 Martyr
There is nothing incorrect about your statements, it's just not the order I'm going in.
And for the sake of numbers, I'll be able to demonstrate how much gains can be made with just a turbo. I think that info will be useful for people interested in a turbo swap, but not necessarily modifying their head.
And for the sake of numbers, I'll be able to demonstrate how much gains can be made with just a turbo. I think that info will be useful for people interested in a turbo swap, but not necessarily modifying their head.
Preloader
The M32 Martyr
I'm aware the stock internals are forged, but that doesn't mean they are rated for the torque abuse I plan to put them through when I reach my target, which will likely require 30+psi boost.
But once I get stiffer springs, I got no issues with ramping up to 25psi on the stock bottom end.
But once I get stiffer springs, I got no issues with ramping up to 25psi on the stock bottom end.
and once you port the head and swap cams your boost will go way down.
in my last car putting on a dp dropped the boost from 20psi down to 18.
porting my head, just the exhaust side dropped my boost from 20psi down to 15.
a 20 pound pulley with my boost reading 12psi haha.
then i dropped pulleys and it went back up but not like everyone else was seeing haha. its fun to play with numbers
factory boost levels just with 185 extra whp
in my last car putting on a dp dropped the boost from 20psi down to 18.
porting my head, just the exhaust side dropped my boost from 20psi down to 15.
a 20 pound pulley with my boost reading 12psi haha.
then i dropped pulleys and it went back up but not like everyone else was seeing haha. its fun to play with numbers
factory boost levels just with 185 extra whp
13TurboLTZ
New member
Sounds like your talking about experience with your soopercharged Cobalt, not necessarilly with the 1.4 turbo. I could be wrong but I dont think opening up the engine drops overall boost level as much on a turbo car as it does one with a blower.