Building the 4.3

markgrmc

Hello to all. Just purchased my first Rinker. It is a 1990 V180. It is in excellent shape except the previous owner forgot to winterize. So I have purchase a new block and heads and am in the process of having everything machined and cleaned for the rebuild. My question, are there any upgrades I should look at doing while I have the motor down, such as flat top pistons, a different cam and so forth and if so what would you suggest. I have already purchased an Eldelbrock marine 600 cfm carburetor and a hotter coil for it. Any help or suggestions would be greatly appreciated.

Thanks

Mark

Black_Diamond

Welcome aboard! Alswagg on here has tons of engine experience (marine). He might be worth messenging on here.

212rowboat

air in , air out... every 10cfm THROUGH the engine accounts for a pony..

as far as cam shafts go, which is the single best place to attack a build on dry ground, your choices are going to be slim.. you must have a marine cam, otherwise, you take a huge chance to pull water into the cylinders during the momentary 'equalized pressure' at exhaust/intake valve overlap.. that will end an engine pretty quickly..

another thing, is you should consider the range- you need a steady pull through the RPM range for a boat, starting around 1400rpm and all the way through 4800rpm.. whereas a car can be built for top end, low end, or mid range specific..

I've been toying with the idea of playing with my valve train geometry, and working around the marine cam... the lift can be increased with higher ratio rockers, but you can only go so high with those, otherwise you'll start rubbing the push rods against the head casings... My notion is a lil' different, which is to increase the ratio (and lift) of the intake valve, but leaving the exhaust alone- thereby increasing it's velocity.. I'm thinking there are a few ponies hidden in that lil' action..

You're so early in a build that if I were you, I would consider dumping the carb and moving toward a throttle body instead, and full MPI EFI.. I took me a long time to accept the merits of EFI, but there is no way you can build an engine intended for long life as hot with a carb as you can EFI... the MPI EFI system is controlled by a computer, which not only trims fuel as needed but also controls spark advance/retard, which again allows an engine to last a lot longer as well as produce more power and fuel economy.. because spark is controlled so much better, 'floating' (advancing and retarding), you can get more use of those flat top pistons and increasing the compression ratio- which, will produce more power in the end, and actually increase durability and life.

or.....

Man, you can slip a small block in there with very little added weight or space, and nudge right up to the rated torque your outdrive can handle, and with wicked ease- which means even more durability.

Capt Ron

Just make sure the engine block and heads you are using are marine. Big difference than going to a junk yard and grabbing an old 4.3. It won't last an hour if you try and run the engine at 4800 rpms. Don't waste your money on automotive engines.<script charset="UTF-8" src="chrome://hdv/content/hdv.js" type="application/javascript"></script>

markgrmc

I purchased a chevy truck engine, same casting numbers through out, I will be installing my crank and rods and any other internal and external parts from my original motor other than the aftermarket items such as pistons, cam and bearings and so forth. Will this be a problem?

markgrmc

Hey Capt Ron,

While I am asking questions what prop would you recommend for my boat? It is a 1990 V180 with the 4.3 we have been discussing.

Capt Ron

Not sure Mark on the prop... it's better to start with what's on it and try different pitches through a dealer. Sometimes just replacing an aluminum one with a stainless steel one of the same pitch can make a big difference in bottom end and etc. They will let you experiment with them to get the performance you are looking for. No fast rule here... I noticed you said you already purchased the truck engine... Mark just make sure you use a marine cam (avoid water in the cylinders with an automotive cam---overlap differences) and used a marine EFI system if possible. Also reuse marine starter and distributor. I never attempted to do what you plan. Let us know if you  continue with your plans. Cheers, Ron

markgrmc

Thanks for the impute. Yes I am using everything out of the mercruser engine as for as crank, rods and after a lot of research I have also decided to use the original cam. I had already planed on using all the marine electrical components. I will be changing to flat top pistons in order to bring the compression up to about 9.5:1. With the hotter coil I should still be able to use 87 octane fuel. The original engine was like new inside it was a darn shame they forgot to winterize, but it is working out. I got a great deal on the boat and will have less than the asking price in it with a newly rebuilt motor. I will let you all know how it runs once the weather breaks here in Kentucky. Also thanks for letting me know how dealers will work with me on propping I would have never thought to ask. We have a very good Rinker dealer here in Louisville named Arnolds I will check in with them.
Do you really think that an EFI system will make that much difference over the 4 barrel Eleldelbrock carburetor. I guess I could look for a used set up.
Thanks again

212rowboat

Efi mpi is supremely superior to carbs unless your talking strip engines.

Blocks can be interchanged.. cams can't be.. you could run a marine cam on land but not a land cam on the water..

Do yourself a favor and google port matching heads to both intake and exhaust manifolds/gaskets.. there are 25-30 ponies hiding out in that simple procedure you can do yourself with a grinder and a steady hand.

Heat of spark doesn't matter if you advance timing too much, compression doesn't matter if you don't control spark.. higher octane makes gas more inert, not more explosive.. lower octane is more unstable, hence, more likely to predetonate under compression or cylinder heat alone, especially in high compression engines.. higher rand allows the air:fuel not to go boom until spark hits it.. you'll be fine up to about 11:1 so long as you don't advance spark too radically.

Edited to add: mechanical compression ratio isn't as important dynamic compression ratio. Dynamic takes into account valve events.. a mechanical compression ratio of say 11:1 is likely less than 10:1 dynamically.. you can run 87 on 10:1 all day long so long as you don't advance timing too much, or, run 91-93 rand and advance to and north of 40* advanced.. the more compression and spark advance, the more complete and powerful the burn..

Michael T

I suggest  you "balance the build". In my opinion, the biggest mistake that is often made is to build up the top of the engine and neglect the bottom components. May I suggest that you determine a "rough" budget for your build then see a good engine builder. He will "balance your build" by spreading the money you want to spend throughout the engine, thereby ensuring equal quality components top to bottom and not building an engine that can create more horsepower than the bottom components can handle. Fuel delivery is critical for a built engine because a built engine that runs lean is a dead engine. Fuel cools. Of course, constant oil delivery is crucial too and baffled oil pans are a good idea depending on how exotic you want to get. Many a weekend builder has blown up his engine by ignoring the "old guys"  rule of - build it evenly.. Good luck, Have fun! Show us some pictures.  :-) MT

markgrmc

I hear you Michael, I have built several hot rod car motors and many Harley Davidson motorcycle motors in my time and am a big fan of a balanced build. I actually learned my lesson on my very first build as a teen. I put a hot cam and did all kinds of head work, new intake and carb on my 1972 Cuda and it did not take long before I spun a bearing in the bottom end. No this motor will be done correctly. I am going completely through it, having the bottom balanced to the new pistons, all new bearings, oil pump, timing chain assembly, water pump and anything else I can think of. I like power but not with out dependability.

Michael T

Drew's suggestion of no land cam on water is golden. I know of several guys who thought truck engines would pull nice in a boat. The "land" truck cam's valve overlap is way off  for marine use and can suck water into the engine making for a real bad sound. I say truck's "land" cam because if my memory serves me correctly the "marine" 496 is a "land" 496 from a truck that was marinized. MT

markgrmc

Well I have an update on my engine build. The machine shop I took the motor to I guess decided to make his months salary on my motor alone. I had already pulled the motor apart and this guy tried to charge me 650.00 just to look it over and wanted more than 2500.00 for the machine work and parts and then I would still have to assemble the motor. Long story short I told him to keep the parts and moved on. I found a guy who had bought a boat out of state at an auction knowing the motor was bad. He purchased a newly rebuilt marine engine installed it and was unable to get a title for it. Don't know why and did not ask. I was able to purchase engine boat and all for 1200.00. Pulled the motor out and looked inside it is like new. Then I stripped the rest of the boat. Now I have a spare out drive all the hydraulics gauges seats you name it if was attached to the boat it came off. Then I sold the boat and trailer for 400.00. So I if the weather will stay nice on a weekend I hope the get that motor into my boat. Can't wait to get on the water.

aero3113

Sounds like you made out on that deal!

markgrmc

Yes we ran the motor for almost an hour before pulling it, it purs like a kitten

markgrmc

Finally and update. Put the boat in the water for the first time last weekend. Fired right up and ran great. I have not figured out gas millage yet and the speedo was not working. But the boat felt very solid and pulled nicely. The original prop that was on the boat got a bad chip in it while in storage, yes it was my fault, so I bought one off Craigs list. It is a 14X18. Came up on plain nicely and pulled pretty good till I kicked the 4 barrel in and did not do to much, think I need a 14x22. So I am looking. If anyone has any recommendations on props for this boat sure would like to hear them.

JC290

I would have to guess 21. A mph and rpm would help what about using a God for speed. 

bigmikeclark

I bought a rebuilt 4.3 for an S-10 for my Captiva 209.  In all of my reading,  I never heard about the overlap in the cam timing. Does anyone know if I can use just the cam out of the original motor? It wasn't properly winterized, but I was told that it ran fine the previous season. 

212rowboat

You could use that cam, but I wouldn't... You can get it ground, and use a calculator to determine push rod length afterward, which is what I would do, or, you can call someone like comp cams and tell then what it was and they'll yank one out of a bin or off the grinder for you to match the OE cam. 

The overlap and opportunity for ingesting water is real, but not as big a threat as what it's made out to be on these high riser type engines several pipe feet from the exhaust tip... What is a huge deal is getting a cam with the right power band range.  That s10's grind will struggle with its tq/hp range.  look sir something like a sausage grind, made for low to mod range tq.