[Bigred89]

Hey all, new Mariah owner. Just bought a 91' MX 19, w/ the merc 4.3l and alpha one. It's the Miami Vice color scheme w/ blue/pink/yellow. Lol!!!! The upholstery is pretty much reached. Engine is in pieces, but the good thing is he gave me a new .030" over block, reconditioned heads, ground crank, new rods.....just need .030" over Pistons/rings and the marine cam & lifters, pushrods, and gasket kit.... It's a family project and the hull is in mint shape, just needs to be buffed back to shine. Got the whole mess for $600 w/ trailer. Will try and share pics as it progresses. image.jpg

[Firestone]

Welcome to the club! Wow what a project. Can't wait to see how it progresses.

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[Bigred89]

I will pretty much be doing everything myself except for machine shop work. I'm taking the block and crank in to verify bore size and journal size befor I order my Pistons/ rings and main and rod bearings. Plus the block needs the cam bearings installed. But other than that it's all me!!!!

[Bigred89]

image.jpgUPDATE....... Engine is built. All parts have been painted, then assembled. Just dropped it in the boat on Saturday.. It exciting to hook up the battery, and see the first signs of life since I bought this thing in a million pieces!!! Slowly, getting things hooked up and checking everything over since it hasn't ran in probably 15 years!!!! Quite a challenge getting everything back where they belong since I was not the one who took it all apart!! Hopefully going to make smoke with it this coming weekend. Question, for breaking in the flat tappet cam, (1500-1800 rpm for 20 min.) can this be done on the muffs, or should the boat be in the water? Was told it should be in the water as you will want the back pressure of the exhaust being submerged....Any truth to this? Kinda Makes sense to me.

[Bigred89]

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[Brian Belcher]

First off-Welcome.
Next, I would suggest you heed Steve's advise on marine engines. I have built MANY MANY engines in my 40 yrs of engines but marine engines are a different animal from what I've learned this year.
I will throw in my .02 and if Steve trumps me, take his over mine.

Engine oil. I use Valvoline VR-1 for the high zinc needed during engine break in. It's $$$ but there's a very good reason. It's great for breaking in new engines.
I run mine at different rpm's for 5 min intervals. Between 1500 and 1800. NEVER let it drop to idle. NEVER. You can go a little over, say to 2200 but don't hold it there too long.
Once it fires up, take it to 1500 and hold it till you get the timing set.
The back pressure myth has been proven a bunch of bunk. I would say doing it in your driveway is fine.
After you get your 30 min break in done, shut it down and do not restart till the motor has completely cooled off. This is to allow the rings and tappets to harden back up and "work harden". The more cycles of running and letting it cool completely down, the harder the wear components will become.
I spent the $12 for a good oil filter like the K&N or Mobil !. This is a small price to pay for something that prevents your engine from dying too soon.
Some folks change the oil after the 30 min break in but I will leave it in for another hour of run time.
That's up to you.
BUT, when you do change it for the first time, buy the 4 oz bottle of zinc and add to your new oil. This will guarantee the tappets don't dish out on you.

I want to reiterate. If Hudson Steve flames me on any of my advise, take his. If we were talking about break in on a LSX or how to set up gears or how to marry the CAN-BUS of two different PCM's , I'd argue till the cows came home.
Enjoy !

[Brian Belcher]

I thought of something else. "SHOCKER!"
There is a 50% chance you'll get the timing 180 degrees. If you're like me, yep, you'll get it wrong. I've learned to not trust the feel of compression over the number 1 spark plug hole. I just bite the dust and pull the tappet cover and watch the intake rocker open, then close, then line the timing mark up. Then I'll stab the dizzy stick and line up number one on the cap.
That works every time. If your luck is even one iota better than mine, just forget everything I just said!!!
Do you have something to put in your drill to pre oil the motor before fire up?

I think I'm as excited about starting her up as you are !! Sorry, I'm just geeky that way.....

[Hudson River Steve]

I agree with Brian about the break in oil. Flat tappet cams require a good break in oil. I like Lucas but there are others as well. The reason to run it in at elevated RPM is that you need max oil pressure...which does not occur at idle...as Brian pointed out. Much of the cam lubrication is from splash and you need RPM to get splash. The need for break in oil is due to catalytic converters on cars. They found that the zinc, calcium and other minerals that provide wear resistance actually cover the precious metals in catalytic converters. So they removed these anti wear components from modern oils. Hence the need for a good break in oil or oil additive with a flat tappet cam.

[Bigred89]

Thank you both for the advise..... Pretty much all of the point mentioned I have got covered already. I'm running the quicksilver 25-40 oil with a pint of Lucas break in additive that has the high ZDDP. Qsilver oil filter. As for the timing, I do exactly what you said. I put my finger on #1 plug hole and bar it over until I feel and hear the hiss of compression, then align the timing marks at TDC for #1, then stab the dizzy in with the rotar pointing at #1 plug. Never been 180 out doing it this way and ensures a quick initial fire up so as not to wipe all my assembly lube off the components. I rebuilt the 350 Tbi in my 89' Chev truck last summer and it is going strong as hell!!! I will heed the advice of letting the engine completely cool after the first few break in runs to temper the components though. I was just checking on the having it in the water for the back pressure on the exhaust thing, I'll be doing it in the driveway.
Now I don't have the out drive on yet, so can I hook the water hose up to the supply hose in the engine compartment to break it in????

[Hudson River Steve]

Yes, you can run it off the hose without the outdrive. I've done it many times without an issue.