4.3 Vortec build up and traps

[dsmmace]

Re: 4.3 Vortec build up and traps

I'm building an similar setup upon finding out my motor was cracked in the lifter galleys.

I decided to build a new motor with flattop pistons with compression just under 10:1, I chose Speedpro pistons. I also decided to convert over to the edelbrock 4 barrel carb and edelbrock intake manifold. When consulting with my engine builder, we decided on the Comp Cam 56-450 cam. This combo allowed me to retain the factory springs and rockers and not have to worry about machining the heads, I don't think there is much of a point of the extra valvetrain parts if you are only going to hit 5000rpm. I spent that money instead on having the heads ported. I also eliminated the balance shaft and had the assembly balanced.

Comp Cams software tells me 310hp and 360 ft lbs of torque, this might be optimistic however from what I read. Going to the 56-470 cam showed me VERY minimal gains and not worth the extra parts.

 

[Bondo]

Re: 4.3 Vortec build up and traps

Bond-o there are few here that can talk to this issue...You and Don are the two guy's i trust with my money and fun....Umm could you make a cameo thought..aka your input would be greatly appreciated....

Ayuh,... Sorry 'bout that,...
I glanced at this thread when it started,+ when I saw Volvo,...
I didn't come back in til just Now..

I'm Impressed,... Sounds like it's gonna be a real Bear,...
Looks like you've been taken care of the Homework alright,...
All these HP #s you guys are throwing around are kinda Meaningless,...
The only #s that matter are the 1s blinking on the gps......

My big concern about Hot Roddin' the 4.3ls is the off-set grind on the Crankshafts...
I've seen a couple that Sheared Off,...
'ell,.. I've got a complete late model 2bbl. carbed motor on a pallet now with a Busted crank...
Sheared off Clean,+ was Running when pulled,... Unfuggin'believeable....
I've been debating whether to recrank that motor, or put the Vortec heads on my 800hr. motor...

I'll be going back,+ clickin' on some of the Cams,.. I haven't yet...
If you get alittle Too Hot,...
Custom Manifolds,+ SSteel Risers leading into thru-hulls might tame the reversions......

 

[Tail_Gunner]

Re: 4.3 Vortec build up and traps

Bondo: My big concern about Hot Roddin' the 4.3ls is the off-set grind on the Crankshafts...
I've seen a couple that Sheared Off,...
'ell,.. I've got a complete late model 2bbl. carbed motor on a pallet now with a Busted crank...
Sheared off Clean,+ was Running when pulled,... Unfuggin'believeable....
I've been debating whether to recrank that motor, or put the Vortec heads on my 800hr. motor...

Very big concern for me too. after all of the bs and if it all works there will be a lot of stress on the crank...aka streetable or waterable power. As in any reconfig there are risks and i am going to place more touqe on the crank at high rpm... And that's the beauty of Don and yourself..that is getting the tech right and will it work..I still have some homework to do on the bottom end but i believe it will be ok. Plz dont read anything into my words.

Now to the above post as to the 266 grind...intresting but i have been there and will post some common info later.

 

[Bondo]

Re: 4.3 Vortec build up and traps

I still have some homework to do on the bottom end but i believe it will be ok.

Ayuh,...

I actually did some googling the other day,...
I hoped to find an aftermaket Forged crank,....

No luck though....

Have you gotten your Degree Wheel,+ Mic's out yet,..??
Kinda hard to figure out where you want to Go with the Cam,...
When We don't know Where We're starting at,...??....

For my V8 built, I've got some Looong drop down Gil Marine risers,...
The water doesn't hit the exhaust stream for 28" of dry pipe run,+ 8" vertical drop from the manifold outlet...
I'll be camming it just Hot enough to maintain some vacuum at idle...

 

[Mkos1980]

Re: 4.3 Vortec build up and traps

918 Springs = better control. Thats whats under my valve covers. With 130lbs on the seat they are a good spring for high rpm's. You wont have any problems with reversion. It sounds weird but the cam I installed in my boat now, is alot smooth at idle then the 109LSA stock flat tappet. LT4 HotCam has 112 LSA

 

[Tail_Gunner]

Re: 4.3 Vortec build up and traps

I'm building an similar setup upon finding out my motor was cracked in the lifter galleys.

I decided to build a new motor with flattop pistons with compression just under 10:1, I chose Speedpro pistons. I also decided to convert over to the edelbrock 4 barrel carb and edelbrock intake manifold. When consulting with my engine builder, we decided on the Comp Cam 56-450 cam. This combo allowed me to retain the factory springs and rockers and not have to worry about machining the heads, I don't think there is much of a point of the extra valvetrain parts if you are only going to hit 5000rpm. I spent that money instead on having the heads ported. I also eliminated the balance shaft and had the assembly balanced.

Comp Cams software tells me 310hp and 360 ft lbs of torque, this might be optimistic however from what I read. Going to the 56-470 cam showed me VERY minimal gains and not worth the extra parts.

If you will read the whole thread you will find using the valve train mods that have posted will not require you to mod the heads at all. And the lift will not casue reversion what so ever..but it will allow a much greater air flow to you engine..how much read the hot rod article and it took a 750 carb to reach its full potential...

Opps this mod should allow 6000 rpm @ wot (and more) but its the drive overheating or more importantly the prop that will spin up that fast and
not cavatate ...Hmm maybe a drive shower huh...the list never ends..


Opps again The above is stricly a opinion your milage may vary...and check every step by a pro..

 

[dsmmace]

Re: 4.3 Vortec build up and traps

I realize my number's should be a bit inflated for hp and torque. I don't think the 9.8:1 will be too much on pump gas whatsoever, especially for one that runs as cool as the marine motors do.

This is the 9th one my engine builder has made with no problems reported and one even has 200 hours on it. The only changes I decided to make is I went with coated pistons and balanced mine for an extra $300.

 

[Tail_Gunner]

Re: 4.3 Vortec build up and traps

Well this would concern me...the 266 has .500 lift and the stock heads and spring's only allow .478. And you seem to plan on no head work.
http://store.summitracing.com/partdetail.asp?part=cca-56-450-8
COMP Cams 56-450-8

$265.95
Estimated Ship Date: Today

Brand:COMP CamsProduct Line:COMP Cams Magnum Hydraulic Roller CamshaftsPart Type:CamshaftsPart Number:CCA-56-450-8Cam Style:Hydraulic roller tappetBasic Operating RPM Range:1,800-5,000Intake Duration at 050 inch Lift:210Exhaust Duration at 050 inch Lift:215Duration at 050 inch Lift:210 int./215 exh.Advertised Intake Duration:266Advertised Exhaust Duration:270Advertised Duration:266 int./270 exh.Intake Valve Lift with Factory Rocker Arm Ratio:0.500 in.Exhaust Valve Lift with Factory Rocker Arm Ratio:0.500 in.Valve Lift with Factory Rocker Arm Ratio:0.500 int./0.500 exh. liftLobe Separation (degrees):112Intake Valve Lash:0.000 in.Exhaust Valve Lash:0.000 in.Computer Controlled Compatible:NoGrind Number:C6 266HR-12Quantity:Sold individually.Notes:

 

[Tail_Gunner]

Re: 4.3 Vortec build up and traps

Ok time for a little turn in direction or maybe a small speed bump ....but it's time to slow down a bit..I was beginning to tare down the engine last night and paying attention to as much as i could i noticed something i was not prepared for.. Volvo put a performance tbi system on this 4.3...It has 2" bores(measure from the butterfly's) that's the same bore size used in the 7.4 truck..sitting on top of a 4bl intake with some kind of tin plate in between the two..That allows it to flow 640 cfm..larger than the carb and much larger than the std 1 11/16 bore which flow 520 cfm..

The tbi ecm in this thing is very crude...time to check out a few things.. Gotta love Volvo

 

[180shabah]

Re: 4.3 Vortec build up and traps

I think the 2" TBI unit was normal (from GM) for the 4.3's.

As for the plate on the manifold, VP does the same thing for 2bbl carbs, hust put an adapter on a 4bbl intake.

 

[Tail_Gunner]

Re: 4.3 Vortec build up and traps

I think the 2" TBI unit was normal (from GM) for the 4.3's.

As for the plate on the manifold, VP does the same thing for 2bbl carbs, hust put an adapter on a 4bbl intake.

The 2" bore flows as much if not more the the carb..Or thats what they say..and if so that would mean the cam has been way dumbed down....Then again Don has said there at the edge...I need to take off a head and see the cast number...i know ii has vortec valve covers.. just dont know if there the good heads...This just surprised me a bit...Damm i wish i knew the stock cam profile..

 

[Mkos1980]

Re: 4.3 Vortec build up and traps

202/213 @ .050, valve lift .404/.410 and LSA of 112 Stock 4.3L Marine/Auto Cam

 

[Tail_Gunner]

Re: 4.3 Vortec build up and traps

202/213 @ .050, valve lift .404/.410 and LSA of 112 Stock 4.3L Marine/Auto Cam

Not to much lift going on there, some where i have some lift flow charts i need to find them

 

[Tail_Gunner]

Re: 4.3 Vortec build up and traps

Found a source for reprograming the ecm...sounded very compotent
http://westersgarage.eidnet.org/index2.htm

 

[Tail_Gunner]

Re: Cam profile ( reversion)

Re: Cam profile ( reversion)

Why are you going from TBI to Carb. Doesn't this make HP drop.

Little update here. Gm puts a 1 11/16" bore on a 4.3 throttle body allowing it to flow at 480 cfm, now that is what i thought i had..4.3 gm spec's 1 11/16 throttle right...wrong.

Volvo puts a 2" bore size on the 4.3 which allows it to flow at 680 cfm. That will allow enough air flow for the head cam combo to work, now the ecm has to be reprogrammed to allow the additional volume of air. And that is the next step.

One side note 1 11/16' tbi bores were used on 4.3 5.0 and 5.7 car engines. The 2.0 bore size was used on the 7.4 liter engine..

 

[Mkos1980]

Re: Cam profile ( reversion)

Re: Cam profile ( reversion)

There was a post about a guy who did a head cam swap on his volvo TBI 5.7L and after he got it tuned it never ran right since then. Low on power , plug fouling and so forth.

 

[Tail_Gunner]

Re: 4.3 Vortec build up and traps

The person whom i talked seemed to have a great grasp of the ecm the head profle and how it all works. Actually he knew what i was doing with the heads.
I have talked to a few programmers there intent was to sell me a ecm wiring harness as all the component's..This will only cost me about 300 to do it with a tbi setup and if it fails..back to a carb.

Probalby what caught my attention the most was his concern for the cam profile... it is a lot of lift and after explaining the springs and spacers he seemed to light up about it. I will be sending him the ecm and all the motor specs along with the mods, and he will determine if he can do it right.

Its getting to be a long winded thread..if you only knew the hours i have put into this...it would take you back a bit. And i appreciate you input Mkos

 

[Tail_Gunner]

Re: 4.3 Vortec build up and traps

Don: i am a bit hesitant to ask you this question, but i must. Do you believe the fuel cell can deliever 80lbs of pressure on there stock fuel rail... I have looked at the fuel cells on the 4.3 to 7.4 there all the same part number.

I know the engine design is almost 8 yrs old, but to me it looks like Volvo way overbuilt the system...aka a 7.4 tb on a 4.3. It will be intresting to see what injector nozzels they put in place.

 

[Don S]

Re: 4.3 Vortec build up and traps

Do you believe the fuel cell can deliever 80lbs of pressure on there stock fuel rail... I have looked at the fuel cells on the 4.3 to 7.4 there all the same part number.

The throttle body is the same. Pressure is determined by the pump, the regulator and the needs of the system. Higher pressure does not mean better anything.
The programming for the injector firing and the size injector is what makes the difference. Along with adusing that fuel mixture to the amount of air allowed by the opening of the throttle plate. That information is given to the ECM by the TPI, then the programming of the ECM takes into account how much air and fueil are delivered by the proper components in the sytem and goes from there.
If you can't program the ECM for all the components you have changed in the engine, both mechanical and electircal, or know the values to program the ECM with. ................ basically you are just tinkering.
I don't know how the ECM is programed, don't have a desire to know. WHat I need to know is how to fix them when they break. Trust me, one off systems will drive you nuts if it doesn't work properly.

 

[Tail_Gunner]

Re: 4.3 Vortec build up and traps

That was a baited question Don sorry, I will need to up the injector pressure from 40lb to 55 or more that was the reason for the question. The guy that is going to map the new ecm has been asking me for a alot of info.

What is really intresting is just how Volvo built this 4.3...they did not spare any money.. they built it as best as it could be for the time with lots of growth for improvement if i can get the info and tech to make it all work. Makes it fun to tinker with..aka cheap..