Question about new vortec long block

typhoonesq

typhoonesq

New member
I did some searching but found nothing really on point. This is what i'm considering:

(1) Rebuilding old block (bad rod) with 4 bolt mains, forged pistons, eagle rods, bearing etc.. With machine work and parts I'm probably looking in $2500 range.

or

(2) I just found a very low milage 4.3 L35 from a 2002 astro van - cheaper than above

Can I simply drop in the L35 and off I go with a good tune? Is it cost effective in the long run or is it better to invest in a solid bottom end from the original motor? Can the L35 handle any kind of abuse?

I think I have realistic goals: a strong running truck that goes low 12"s or high 11"s with around 15 psi ( I'd like to keep the stock turbo for now).

Any advice is greatly appreciated.
 
bezerk

bezerk

New member
Re: Question about new vortec long block

btw a 2002 is a vortec not a l35? running low 12's and 11''s needs a bit more if you want it to last long imo
 
supersports10

supersports10

New member
Re: Question about new vortec long block

ok lets start from the top....2002 is not a L35 92-95 cpi is a L 35.

L35 has cast pistons and cast mains......wont live long under 15 psi.

96-PRESENT is a vortec , better hyperutectic pistons, better heads, but vortec bolt patteren for the intake. requires modifying the lower intake. under the right tune it can live a long life.

a link for you...... http://www.syty.net/forums/showthread.php?t=20725






typhoonesq said:
I did some searching but found nothing really on point. This is what i'm considering:

(1) Rebuilding old block (bad rod) with 4 bolt mains, forged pistons, eagle rods, bearing etc.. With machine work and parts I'm probably looking in $2500 range.

or

(2) I just found a very low milage 4.3 L35 from a 2002 astro van - cheaper than above

Can I simply drop in the L35 and off I go with a good tune? Is it cost effective in the long run or is it better to invest in a solid bottom end from the original motor? Can the L35 handle any kind of abuse?

I think I have realistic goals: a strong running truck that goes low 12"s or high 11"s with around 15 psi ( I'd like to keep the stock turbo for now).

Any advice is greatly appreciated.
Click to expand...
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: Question about new vortec long block

E-Rue has a thread on it. I also started doing a swap in the project section, I have a few links in my thread to E-Rue threads.
 
clone 94

clone 94

New member
Re: Question about new vortec long block

supersports10 said:
L35 has cast pistons and cast mains......wont live long under 15 psi.
Click to expand...


mine lived fine with 25 psi. the tune plays a huge role. the only reason it held together IMO was because i spent countless hours tuning it until it was perfect

so the question is, how confident are you in your tuning skills?
 
typhoonesq

typhoonesq

New member
Re: Question about new vortec long block

clone 94 said:
mine lived fine with 25 psi. the tune plays a huge role. the only reason it held together IMO was because i spent countless hours tuning it until it was perfect

so the question is, how confident are you in your tuning skills?
Click to expand...

I can't say my tuning skills are great considering I've never tuned a anything but I've read a lot of posts here and will be getting the necessary software.
It seems regardless of how well the motor is build, a tune is absolutely necessary for these motors to survive.

Question is: Go vortec or go rebuild?:crazyeye: At this point i'm leaning Vortec (heads, better strength and cost). Rebuild mine is going to cost a lot more but would be stronger in the long run.

If you guys had to do it again - what would you different or the same?
 
turbodig

turbodig

Active member
Re: Question about new vortec long block

Realistically, you're not gonna see hi 11s/lo 12s on a stock turbo @ 15 psi.
You're probably not gonna see that at 20 psi, either. (At least not in a full-weight Ty)

There's nothing wrong with the vortec motor, as long as you get things tuned properly.
With race gas or a good pump gas/alky tune, you should be able to hit mid-low 12s.
 
supersports10

supersports10

New member
Re: Question about new vortec long block

turbodig said:
Realistically, you're not gonna see hi 11s/lo 12s on a stock turbo @ 15 psi.
You're probably not gonna see that at 20 psi, either. (At least not in a full-weight Ty)

There's nothing wrong with the vortec motor, as long as you get things tuned properly.
With race gas or a good pump gas/alky tune, you should be able to hit mid-low 12s.
Click to expand...

agreed!!!!:tup:
 
csx turbo

csx turbo

"Me, sarcastic? NEVER..."
Re: Question about new vortec long block

Our turbo 4.3s have different pistons w/ a lower compression then the Vortecs; if you just drop in a Vortec motor w/o changing the pistons you are going to run into a lot of knock as you increase the boost. Your new Vortec motor won't last too long... According to my factory service manuals some compression ratios are:

92 LB4 9.3:1
92 L35 9.05:1
2003 Vortec 9.2:1
SY/TY 8.35:1

:2cents:
 
supersports10

supersports10

New member
Re: Question about new vortec long block

csx turbo said:
Our turbo 4.3s have different pistons w/ a lower compression then the Vortecs; if you just drop in a Vortec motor w/o changing the pistons you are going to run into a lot of knock as you increase the boost. Your new Vortec motor won't last too long... According to my factory service manuals some compression ratios are:

92 LB4 9.3:1
92 L35 9.05:1
2003 Vortec 9.2:1
SY/TY 8.35:1

:2cents:
Click to expand...

yes , but the vortec heads are far superior to the sy/ty heads and are way less sensitive to knock.

just run alky, or e-85:tup:
 
csx turbo

csx turbo

"Me, sarcastic? NEVER..."
Re: Question about new vortec long block

supersports10 said:
yes , but the vortec heads are far superior to the sy/ty heads and are way less sensitive to knock.
Click to expand...

Just curious my friend; what does the better air flow of the Vortec heads have anything to do w/ the knock characteristics of the Vortec engine especially in a turbocharged application? Knock is the ignition of the A/F mix due to heat or high compression before the sparkplug can ignite the mixture. Higher compression can cause this. The better flow of the Vortec heads isn’t going to help this…
 
bezerk

bezerk

New member
Re: Question about new vortec long block

advantage of running a newer vortec engine is that is also has alot more hp n/a so with less boost you will compensate a bit
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: Question about new vortec long block

csx turbo said:
Knock is the ignition of the A/F mix due to heat or high compression before the sparkplug can ignite the mixture. Higher compression can cause this. The better flow of the Vortec heads isn’t going to help this…
Click to expand...

Your right, but the heart shape combustion chamber of the Vortec is less prone to knock.
 
csx turbo

csx turbo

"Me, sarcastic? NEVER..."
Re: Question about new vortec long block

Sy#2661 said:
Your right, but the heart shape combustion chamber of the Vortec is less prone to knock.
Click to expand...

Good point, I hadn’t considered the better air/fuel mixture due to the “Vortec” created in the combustion chamber. Though, if time and funds permit I would still change the pistons due to two reasons: first being the higher compression, and second if the Vortec did come w/ hypereutectic pistons as Supersports10 mentioned (I don’t believe they did…) they are a very bad idea in a turbocharged application. The extra silicone in the hypereutectic pistons decreases there resistance to the thermal loads in turbocharged engines. This knowledge comes from Ed Peters, a retired Chrysler failure analysis engineer who did a study of hypereutectic pistons.
 
clone 94

clone 94

New member
Re: Question about new vortec long block

9:1 is not high compression

every turbo motor i have ran in my truck and will run in the future has been and will be no less then 9:1 compression, especially if you have vortec or alum heads
 
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