4.3 Marine to Auto Block Swap

[zealer]

Got the engine out today, I'm very pleased to say! It went very smoothly. To gain enough clearance I had to take carb off, manifolds and distributor cap before lifting engine. Now I'll look for a replacement. I was planning to swap the distributor, water pump/thermostat housing, intake+carb and accessories (alternator, power steering etc) from the Mercruiser to Chevy motor, and that is it. Any objections or additions? Also need to compile a list of gaskets. I'll need intake gaskets, carb, exhaust, waterpump and one for the outdrive. Did I miss anything?

 

[thumpar]

Don't forget to change the core plugs to brass.

 

[Walt T]

Don't waste time testing the batwings. Get rid of them. I wouldn't warranty an engine with those. Yes, manifolds are relatively expensive. I remembered a post here on those a couple years ago did a search and found it. Should be helpful

http://forums.iboats.com/forum/engi...s/562336-batwing-exhaust-manifold-replacement

 

[zealer]

Here's a couple of pics of the motor coming out of the boat.

Hopefully will pick up my swap motor tomorrow evening or Thursday morning. Quick question, think I should change oil pans?

 

[500dollar744ti]

You take it out the same way you would in a car. you have to pull it forward, then up. If someone got it in there, you can get it out.

 

[zealer]

Ya I know, I got it out no problem! That engine bearing tree is mine. Waiting for a new Vortec to grow...

 

[500dollar744ti]

Yeah, a tree and a hoist can go a long way

 

[zealer]

Went and looked at a Jimmy last night for a donor motor. It made some ticking noises at startup which I didn't like, so the search continues.

 

[HT32BSX115]

OMG!! Batwings!!! You need to get those off the new engine or they'll kill that one too....

Yes. I would dump the "Batwings" too!

As much trouble as it is to R&R the engine, it'll be worth it to go to center-risers. I would even consider a used closed cooling setup too.

 

[zealer]

Yes. I would dump the "Batwings" too!

As much trouble as it is to R&R the engine, it'll be worth it to go to center-risers. I would even consider a used closed cooling setup too.

I will look into replacing them. So far it seems I can get a China (HGE) set for $500 + shipping. Unfortunately, I live in Canada so 1) shipping will be expensive; 2) I will most likely need to pay duty and; 3) Not confident on the quality. By the time its at my door it'll probably be just as or more expensive as buying genuine via local place.

I asked a local marina, through them it'll be about a grand. Also need to source an "engine alignment tool", or I was hoping to find a scrap sterndrive and take the driveshaft off of it and use it as the tool. That would work, no?

 

[Bondo]

I will look into replacing them. So far it seems I can get a China (HGE) set for $500 + shipping. Unfortunately, I live in Canada so 1) shipping will be expensive; 2) I will most likely need to pay duty and; 3) Not confident on the quality. By the time its at my door it'll probably be just as or more expensive as buying genuine via local place.

I asked a local marina, through them it'll be about a grand. Also need to source an "engine alignment tool", or I was hoping to find a scrap sterndrive and take the driveshaft off of it and use it as the tool. That would work, no?

Nope,.... Ya need the Tool,.... the driveshaft is very different,....

 

[HT32BSX115]

Also need to source an "engine alignment tool", or I was hoping to find a scrap sterndrive and take the driveshaft off of it and use it as the tool. That would work, no?

Right. (no) it won't work..You can buy one on ebay or if you know someone that works at a machine shop one can be easily made in less than an hour even with coffee breaks!

 

[zealer]

OK, thanks for the tip Bondo, HT32. I had called a marina the other day (which is where I got the idea of a driveshaft) and asked them about the tool, and they said they didn't sell them and recommended I just use a driveshaft. I'll keep looking. They are available on eBay, but again shipping cost and time makes it not worthwhile. It will be better for me to source locally. I don't know anyone that works at a machine shop, but regardless I can phone around. If I can get it done quickly for $100 I'd be super happy.

Also sourced a Jimmy as my donor vehicle. I should be getting it Monday, which is kind of annoying because I wanted to start this weekend. Have to wait for the paperwork...

 

[Bondo]

OK, thanks for the tip Bondo, HT32. I had called a marina the other day (which is where I got the idea of a driveshaft) and asked them about the tool, and they said they didn't sell them and recommended I just use a driveshaft. I'll keep looking. They are available on eBay, but again shipping cost and time makes it not worthwhile. It will be better for me to source locally. I don't know anyone that works at a machine shop, but regardless I can phone around. If I can get it done quickly for $100 I'd be super happy.

Also sourced a Jimmy as my donor vehicle. I should be getting it Monday, which is kind of annoying because I wanted to start this weekend. Have to wait for the paperwork...

Ayuh,.... It happens pretty quickly, when ya got 'em both, side by side,....

Usin' 2 Stands saves alota bendin' over,....

 

[zealer]

Quick update: still waiting for my donor motor. Was supposed to pick up the vehicle day but there was an issue with paperwork... Surprise surprise! I expect to take possession Wednesday or Thursday, otherwise i will look elsewhere. Only catch is that this motor in particular has very little use. It will be very difficult to find another like it for the same price. Anyway, my marine motor is mounted on a stand, waiting for the donor to arrive and occupy the stand next to it so I can begin transferring the necessary pieces. I hate waiting

 

[zealer]

It's been a week since my last update. A lot has both changed and been accomplished since then. To start, I received my donor vehicle last Thursday. It is a 2000 Jimmy. I was planning to pull the motor and scrap the vehicle. However, it is in such good shape that I have decided to keep the Jimmy (it will replace my Silverado). the Jimmy needs brakes and maybe wheel bearings, but otherwise it is a cream puff. Consequently, I bought another motor from a scrap yard. It is out of a '97 Astro.

I have nearly finished the swap. Here are some of the notes I've made. Keep in mind that my Mercruiser is a 2001, and the replacement is a 97 GM truck engine.

Oil Pan and pump
Marine and auto pan are different. Auto pan is actually deeper, and subsequently has a longer pickup. Oil pumps are the same (#GL214). I swapped the mercruiser pan onto the Astro engine with the pickup as well (it is a press fit pick up).

Motor Mounts
Motor mounts are in the same location with same triangular bolt pattern, however my 'marine' 2001 block used 7/16" bolts whereas the Astro motor uses 3/8" bolts. Perhaps this was a change made by GM between '97 and '01.

Flywheel
Astro motor uses a much lighter flywheel. I swapped the flywheel from the marine motor to the astro replacement motor.

Freeze Plugs (core plugs, expansion plugs, whatever you want to call them)
Marine engine is brass, Astro is steel.

And then of course are the accessories. I swapped all the Mercruiser gear onto the Astro motor. I read somewhere that Mercruiser waterpumps have a different (steel?) impeller, but I did not verify this, or even look at the part numbers (I suppose I could). Starter, distributor, alternator, water pump, brackets, engine harness etc came off the Mercruiser and onto the Astro.

 

[zealer]

Noticed another difference. The 97 (Astro) block uses 3/8" bolts for the flywheel cover, whereas the 01 block uses 7/16". I suppose this was a casting change GM made at some point between the 1997 and 2001. The bosses are also slightly shorter.

 

[Bondo]

Noticed another difference. The 97 (Astro) block uses 3/8" bolts for the flywheel cover, whereas the 01 block uses 7/16". I suppose this was a casting change GM made at some point between the 1997 and 2001. The bosses are also slightly shorter.

Ayuh,.... Are ya Sure those aren't Metric threads,..??

 

[Fishermark]

...

Oil Pan and pump
Marine and auto pan are different. Auto pan is actually deeper, and subsequently has a longer pickup. Oil pumps are the same (#GL214). I swapped the mercruiser pan onto the Astro engine with the pickup as well (it is a press fit pick up).

It is always a good idea to tack weld the pickup tube onto the oil pump whenever it is a press fit. That's the last thing you want falling off!

 

[zealer]

Bondo, a 3/8" bolt screwed all the way in by hand, no extra effort needed. I did consider metric screws, but again with the ease that the 3/8" bolts went in, I stuck with them. Too late now for the oil pick up, pan is already on. In fact, entire engine is back in boat, assembled and ready to rock... Well, almost ready to rock. We dropped her in last night, it seemed to go well. Then all of a sudden we notice the bilge filling with oil. Quick inspection shows the pipe fitting for the oil drain broke at the block (I guess we bumped something). Luckily we were able to extract the broken fitting fairly easy and install a new one. That was problem 1. Problem 2 came whilst putting the sterndrive back on. We had a heck of a time keeping it in gear and aligned. Eventually got it, but anyone and everyone could tell it was our first time. Now it's time to fire up the engine. Hooked the battery up, checked all connections and turned the key. She cranked over a few times. Didn't start - no problem, probably waitin for fuel to make it to the carb. I go to turn the key again and all I get is a loud click. Damn slave solenoid is clicking its brains out. This is problem 3, which is still not solved. Solenoid is getting power, but when key is turned it drops to 0 V. Interestingly enough, jumping the solenoid causes the 50amp breaker to trip. Even with a non functioning slave, I thought jumping the terminals would still allow power to go through. Thus I'm not sure if the problem is the slave or elsewhere.