Decided to build a 5.7 Vortec and do it right!

[Swill008]

Reference thread [http://forums.iboats.com/mercruiser-i-o-inboard-engines-outdrives/5-7-vortec-2bbl-350-mag-mpi-conversion-633726.html]

I purchased a 5.7 LongBlock from a mass rebuilder and got a lot less than what I paid for. Long story short (can read my chronicles above), I'm going to build one correctly.

Engine will be a 350 MAG MPI 300HP behind a Alpha 1 Gen 2 sterndrive.

Now about me: I can read manuals, I can use precision tools I have technical skills (more related to helicopters and turbine engines) I suck with English and writing cursive! I only know bad English and improper punctuation.

With that said I'm in no way an automotive/marine guy. This engine is a project for a 1999 21ft SeaRay 210 Sundeck - father/son restore-RePower project. I want cheapest pump gas ability when complete.

So, questions :

Bondo pointed me to link about Vortec squish and how it's a bad idea to use flattop pistons because of no squish area provided. I'm sold! So I'm trying to get my head around this. In the referenced link above my last few posts carry on my questions.

What is the proper procedure to obtain the .043 squish area? I understanding decking, milling and mockup.

I'm thinking of going with D-Dish style pistons (cast or hyper), but I have to get my pistons .004 in the hole. My head gasket is .039 compressed. Do the pistons need to be a certain depth to account for the increased compression (basically the depth of the D milled in the piston)?

I don't want to change piston rods, so only two ways to get there I'm thinking. Lower piston wrist pin location or almost zero decking my block. If I zero deck I'm thinking I have to mill my intake to match. However I don't know if you can buy pistons with different wrist pin locations, or if I'm making this too difficult

Thanks for any replies and suggestions. Please keep in mind I'm a newbie with enough experience to be dangerous!:lol:

 

[alldodge]

Re: Decided to build a 5.7 Vortec and do it right!

I would stay away from custom pistons, would be cheaper to go with new rods before you go that route. If you have already checked your squish area and it is 0.000, then go for a thicker head gasket. The link below is just for Fel-Pro and one site but there are others.

http://www.summitracing.com/search/product-line/fel-pro-performance-head-gaskets

 

[Bondo]

Re: Decided to build a 5.7 Vortec and do it right!

Ayuh,.... Look through this google search for all the different pistons available,...

The 3rd link down goes to Hot Rodders forum,... You can spend a month in there reseachin' yer plan,...
Lots, 'n lotsa Great info in there,... just remember yer buildin' a boat motor, 'n not a Screamin' Hot Rod,.....

There's a couple of common replacement pistons that'll work with yer recipe,...
Yer gonna need somethin' like the 12cc, or 18cc pistons to keep the compression ratio 'tween 9, 'n 10:1,...
'n as I said earlier, go with Hyper pistons, donno's there's any cast, like ya need anyways,...

Like I said, after ya buy the pistons, yer machinist will deck the block,..
yer sayin' .004",... it might be .003, or .005,...
Havin' yer new pistons hung on yer resized rods, that can be figured out,...

Yer intake won't need machinin' at the levels of deckin' We're talkin' 'bout,...
Even down to 0" deckin', ya don't need to mill the intake,...

 

[Walt T]

Re: Decided to build a 5.7 Vortec and do it right!

Hyper are best.

383 Small Block Best Piston Photo 15

 

[Swill008]

Re: Decided to build a 5.7 Vortec and do it right!

Looking at these Keith black pistons, 4.030 and +12cc. These looked mirrored for the vortec style head. I've read some people don't like them because they're different ring gap procedures.



Anyone explain why you do like or don't like the Keith Black pistons?

KB-193-030

I need +12cc to keep me at 9.5CR, stock was 9.3:1CR.

Accounting for the gasket bore of 4.125 my CR would be closer to 9.52 but that is pretty close to where I'm thinking I should be.

I'm thinking .25CR won't hurt me.



I'm open to suggestions, I would actually really like alternate suggestions.

Deck Height (9.025") - Rod Length (5.7") - half Stroke (1.74") - Pin Height (1.56") + Gasket Compressed Thickness (0.039") = 0.64" Quench.



Here is a screen grab of a sweet free calculator I found on the net.

To get to .043 the two factors I can change is cleaning the deck by .021 leaving .004 piston to deck or I can do a combination with head gasket and decking.

I'm thinking remove .021 from the deck and run common Fel Pro marine head gasket.

I'll have to deck to clean or do a combination anyway. So get it all at once. Ideas?

 

[Walt T]

Re: Decided to build a 5.7 Vortec and do it right!

The different ring gap procedures are supposedly because of the difference in expansion rates using Hyper/cast/forged pistons. Keith Black techs themselves say its not that big a deal being it's such a tiny difference. With the shorter skirts some folks say they can be noisy at start up but I've never experienced this. You're doing fine but you're starting to confuse yourself. Hot rodding forums are great but every post seems to be a different opinion. Just keep in mind they tend to think in terms of automotive use and marine is different. Your math looks great, mirror pistons are a good choice, compression should be about right. Keep it simple.

 

[Swill008]

Re: Decided to build a 5.7 Vortec and do it right!

Trying to find information on my mercruiser stock 1998 5.7 350 880 casting block.

It was freeze busted and I'm wanting to use the connecting rods. Looking at the Mercruiser #24 it states forged steel not powdered metal. My rods look clean almost powdered metal, I can see what looks like a casting line. So I'm thinking not PM, also these should be 5.7's right?






I'm purchasing ARP hardware and want to get the correct kit, 6003 for non powered metal and 6005 for powdered metal.

Also looking at a SCAT crank, if I have to turn my existing crank I'm looking at 125ish. But a new scat with one pice and 2.1" would be 200 at my door. Thoughts on a SCAT crank? Some say junk others like it.

Also is a pressed piston wrist pin better than a floating pin? Can my stock Rods (used) be configured either way, floating or pressed?

Right now mine are wrist pin pressed into the rod and floating in the piston. The KB193's I ordered have spiral locking clips, says either pressed or floating. Trying to get my head around how to set mine up with these stock rods.

Thanks for any help/clarification!

 

[Bondo]

Re: Decided to build a 5.7 Vortec and do it right!

Ayuh,.... If yer gonna buy a new crank,.... Go Stroker,....

Yer rods resized, 'n ya need pistons anyways, so get the Stroker pistons to match,...
No reason to go to floatin' pins,... plenty of other, better places to blow yer cash,...

Ya shouldn't be Orderin' Anything, til yer recipe is Rock solid, Then buy yer parts,...

I can't say on yer rods, I'd think they're whatever Chevy was puttin' in their pickup truck motors that year,...

 

[Tail_Gunner]

Re: Decided to build a 5.7 Vortec and do it right!

Ayuh,.... If yer gonna buy a new crank,.... Go Stroker,....

Yer rods resized, 'n ya need pistons anyways, so get the Stroker pistons to match,...
No reason to go to floatin' pins,... plenty of other, better places to blow yer cash,...

Ya shouldn't be Orderin' Anything, til yer recipe is Rock solid, Then buy yer parts,...

I can't say on yer rods, I'd think they're whatever Chevy was puttin' in their pickup truck motors that year,...

Bingo map the build then proceed......drop the FI and the cooling system....here's a bold statement unless your in salt water the cooling system closed...is pretty much a waste of money. Ohh and the FI...Ive tinkard now with FI programming fro 4 yrs...one well tuned carb same result's...Dished piston's good forethought...stroker even better.


Light duty truck applications with 9.025 inch deck height. Check stock rod balance pad to piston clearance. Not legal for sale on pollution controlled vehicles. Suitable for boost applications.

http://www.summitracing.com/parts/uem-kb142-030/applications/make/chevrolet/year/1998

 

[Silly Seville]

Re: Decided to build a 5.7 Vortec and do it right!

Stroke it, stroke it, stroke it! If you're starting from the bottom, spend the few extra boat bucks and go to 383 cubic inches! I wish I did on my last build, but I was too lazy to clearance the block and was in a hurry. If you do go that route...be gentle with your right hand...on the throttle!

 

[Swill008]

Re: Decided to build a 5.7 Vortec and do it right!

Thanks guys, but I'm on an alpha 1 gen 2, so I'm trying to stay in the 300hp range. I've already decided on my build. Got an 880 4bolt main in the shop being square decked, and cut down. Trying to keep it simple.

I'm going to put my pistons in the hole by .004 (deck .021) and use .039 head gasket with KB193-030 Molly ring sets. Head pressure test and cleaned with SS valves. I'm on a 350 MAG MPI setup with closed cooling with a 4 inch heat exchanger.

These look good!


I'm trying to wrap my head on how to get these pistons on my rods. I'm sure the machine shop could explain it but it's on my mind tonight. :cold:

The stock pin journal was 0.9269-0.9270 per the manual and my new piston wrist pin is 0.9272. I'm reading that floating is better than pressed. I'm asking your opinions on that statement. Should I stay pressed or go floating?

Also if I have to re-grind my crank, might as well buy a new scat for 200 since it will cost me 125 anyways. What the thought of the scat crank, ok for my build or buy another from a diff company?

If I had a bravo I'd stroke it in a heartbeat! Sorry guys! I would love to, anyone got a bravo inner and outer to give me I'll build you an awesome stroker then!

 

[Scott Danforth]

Re: Decided to build a 5.7 Vortec and do it right!

I would stroke it, put synthetic oil in the outdrive, and simply watch your hole shot.

No need for floating pins in a boat.

 

[Swill008]

Re: Decided to build a 5.7 Vortec and do it right!

I would stroke it, put synthetic oil in the outdrive, and simply watch your hole shot.

No need for floating pins in a boat.

Thanks!

If I understand correctly I can't use 5.7" rods in a stroker can I? Also I'm running FI, wouldn't that mess up my mapping and fuel/air mixture?

 

[Silly Seville]

Re: Decided to build a 5.7 Vortec and do it right!

If I understand correctly I can't use 5.7" rods in a stroker can I? Also I'm running FI, wouldn't that mess up my mapping and fuel/air mixture?

Absolutely you can use a 5.7 rod in a stroked engine...and you can get any map settings via a programmer you want for that set up. There are currently Mercruiser 383 MPI's available for sale. They just call them the Horizon 6.2

Please understand something...there are folks still running around with 268 Sundancers that have the factory installed 454/Alpha 1 combo. The 454 was rated at 310/330 hp, and while yes, it is still the torque king, not everyone ripped their Alpha's to shreds using those monsters. It's all about how gentle you leave the hole. Take your time getting up on plane with your Alpha. A 320 hp stroker is not going to just magically gobble up the gears of your outdrive...you would have to force feed it with your throttle hand!

And don't even consider a Bravo swap unless you have lots of cash piling up all around your house that you wipe your boat with. Many folks have asked about such swaps, and the answers are always the same. Don't bother. Run what ya brung! You can replace three Alpha's from SEI for what a proper Bravo swap will end up costing you. Just my opinion, but I think your money is best spent on a stroker the first time around. Seriously.

 

[Walt T]

Re: Decided to build a 5.7 Vortec and do it right!

Machine shop will install pistons on the rods. On a freeze damaged engine I have found camshafts and crankshafts bent (slightly, but bent) due to the journals being moved as the ice expands. The cam and crank are junk. The rods were attached to the crank. If they are bent or not you best have the machine shop check. One slightly bent or twisted rod will cause vibration and greatly shorten the life of the motor. In my experience, freeze damaged blocks are junk including all the parts inside of it. If the valley is cracked apart then the cam and crank WILL be bent and the rods and pistons are highly suspect. In my opinion the guys are pushing you in the right direction. Build or buy a nice stroker. Doesn't have to be a balls to the wall performance engine. Don't try to save a few bucks on suspect parts. No one ever complained of too much power. Well, My gramma did when I took her to her Bingo in my '70 429 Ranchero which used to have 396 El Caminos for breakfast. Then she said she didn't like my 390 'Stang 4 speed because it 'mussed up my hair' when I shifted from 1st to 2nd and got a good chirp. Gramma had to take the bus after that. That'll teach her to complain. 'Course now she's up there probably getting rides to Bingo in all the old cars I still wish I had.

 

[Tail_Gunner]

Re: Decided to build a 5.7 Vortec and do it right!

OBD Diagnostics

There's alink for mefi tuning and he is one of the best in the business. Simply give them a call and they will take it from there...Now you have a 99 350 if ive read this right, there is a product id on your ecm if you could post it it will identify wether you have a mefi or a merc 555 ecm.

 

[Swill008]

Re: Decided to build a 5.7 Vortec and do it right!

You guys almost have me pulling the trigger on the 383, almost.

If I go 383 I will have to get the rotating assy balanced. Then an hormonic balancer for it and a new flywheel. (Please correct if wrong)

Clearancing the block I could do, with care and reading up and educating myself. The remap wouldn't be too costly - Tail_Gunner I have an MEFI 3 controller.

I actually have three complete MEFI 3 FI systems, including controllers and intakes. I'll sell the systems to recoup some of my boat bucks! Along with another closed cooling 4 inch heat exchanger. (Got a deal - so bought 3 complete setups)

I'm thinking it's going to cost about a grand in machine work with head job. So I'm getting cost conscious.

Trying to figure out what my cost will tally up to.

Walt T, I'll have the shop perform a runout check on the crank and cam to make sure it's straight. The rods I'm not sure how to check but I'll ask them to. All in all if I get scared I'll replace the components.

Btw I will not consider a bravo swap unless it's free - I was being funny I'll but a boat with that in it first.

I did read in another forum that an 880 casting block did not accept the longer stroke of the 400 crank - positions were coming too far out of the bore, Making a racket. Maybe it was his setup, I don't remember wich forum but that had me second guessing. (Put together wrong maybe?)

So what would I need to do, to go from my stock 5.7 to a 383? Any good threads showing the entire build. The ones I read have with talking about the build up or completed projects without enough detail. Would I have to advance the cam or retard it? Would want to keep as simple as possible.

Any help much appreciated.

 

[Bondo]

Re: Decided to build a 5.7 Vortec and do it right!

If I go 383 I will have to get the rotating assy balanced. Then an hormonic balancer for it and a new flywheel. (Please correct if wrong)

Ayuh,.... The harmonic balancer, 'n the flywheel are balanced WITH the rest of the rotatin' assembly, not added later,....

Yer Machine Shop will inspect, 'n resize yer rods for ya,...

'n No reason to advance, nor retard the cam,...

 

[Swill008]

Re: Decided to build a 5.7 Vortec and do it right!

Can I use existing flywheel and hormonic balancer? Or would I need new?

 

[Bondo]

Re: Decided to build a 5.7 Vortec and do it right!

Can I use existing flywheel and hormonic balancer? Or would I need new?

Ayuh,.... Yer harmonic balancer, 'n flywheel are neutral balance,...

You need a New weighted balancer,... yer's can't be rebalanced,...

The flywheel, you could buy a weighted wheel, or yer's can be rebalanced by yer Machinist,...
Ask him 'bout pricin', as a new 1 may, or may not be cheaper,...