Exploration about Explorer engine change

[Jim Marshall]

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I have a Glastron ?74 boat with a 302 Ford 200hp engine. It is a Volvo/Penta I/O unit. After finding the old engine was questionable (it was locked up which turned out to be the starter) I pulled it out and tore it down. Basically, with 350 total hours it looks good.

In the meantime I had the opportunity to pick up a brand new ?95 Explorer engine and I thought I would add EFI to it.

Scrounging here and there I picked up marine EFI parts to find out it was a bit tougher than I thought. There is the matter of the exhaust sensor, the different distributor, and on and on. That made doing something to the old engine a bit more attractive. So, I generated a new set of questions.


Q1?How good is the Explorer compared to the old engine?
I guess it has GT40 heads, roller cams and other things and can pump out significantly more hp. Is there a downside besides having to round up a 50 oz flywheel and a few other things.

Q2?How about the old engine?
I picked up a Lunati cam and some Cal Comp roller lifters and was going to to that way before I picked up the Explorer. In some ways it would be easier to go back to the old engine.

Q3?Am I being too spooked by the complexity of the EFI?
I found that the biggest challenge is finding a place for the oxygen sensor. I found one at the end of the exhaust manifold where the cooling channels would not be a problem, but he EFI still has its complications compared with carburetion.

Q4?Are marine manifolds really that restrictive?
This manifold runs out the back where it takes a 90 degree bend, joins up the two sides and then exhausts underwater.

Q5?Are marine engines really different from auto engines?
I have found about 70% of the people I talk to say no. The rest tell me I they have different clearances, different cams, different components.
So, here is your chance to throw in your two cents and help me in the meantime.

Thanks,

Jim

 

[JustJason]

Re: Exploration about Explorer engine change

1. What is an Explorer engine??? Never heard of one before. Is this just a V8 out of a ford explorer suv? Got a webpage that advertises the spec?

2. Is the old engine good or bad? What's the compression in all 8 holes? You said you tore it down, did you plastigauge the lower end?

3. Yes and no, depends on how you are with electronics and how they all work together. What efi system are you using? Hope it's not automotive. There is MEFI 1 through 5, then there is the motorola PCM 555 digital. None of them use an 02 sensor. Only the california 10+ engines are requireing 02's as of now, but expect most of the states to follow. If your doing a re-fit on an older hull you don't need to be messing around with them.

4. Yep. But it's not just the manifolds, it's the system as a whole. Doesn't matter to much though. Straight pipes only give you a couple of HP + the headache of constant noise. To get real power numbers exhaust systems in anything need to be tuned exhausts that help in the scaveging of exhaust gasses (think 2 stroke dirt bike exhaust pipes, the bulge in the pipe is there for a reason.

5. The block, crank, rods, and pistons are more or less the same. Marine engines are cam'd differently. But then there are all the sub systems, Cooling systems, ignition systems, fuel systems, charging, starting, and as you already see exhaust systems... is what really make them different. Remember, every system works together to make the motor function as a whole.