Engine Swap - Mercruiser/Chevy

[searaysteve]

Hello All,<br /><br />Purchased a '77 195 Sea Ray w/ a cracked block for a song and am preparing to swap out the motor in the next month or two.<br /><br />Have been reading a mercruiser manual and have quick question about pullin and replacing the block.<br /><br />Let me preface this w/ the fact I have done plenty of shade tree work on old 'hot rods' and am fairly technically inclined <br /><br />Powertrain is a smallbock chevy w/ a mercruiser outdrive of '77 vintage.<br /><br />I know if I pull the oudrive for removal & re-install it is imperative to properly align the drive spline as to prevent damage (will probably take to a amrine mechanic for this if going this route)<br /><br />Question:<br />Can I pull the block without removing the vertical drive?<br />Appears to be possible according to the Seloc manual if you can slide the motor 8" or so foward to clear the spline.<br />According to the manual; if done this way and the motor mount height is not changed there is no concern w/ haveing to do the critical allignment check.<br />My case w/ involve replace the origianl block w/ a different, but am hoping there will not be any orientation change.<br /><br />Can I do this w/out having to check allignment or would you reccomend having alignment done anyway.<br /><br />FYI: Motor will be pushing the limits of power/torque @ approx 360hp & 380 ft/lbs<br /><br />Thanks in advance<br />Steve

 

[daveswaves]

Re: Engine Swap - Mercruiser/Chevy

See if we can get some others to log in on this too but here is my 2 cents worth. In my opinion you may as well remove the outdrive anyway to replace water pump, check/grease universals. You may also want to change exhaust boot, drive boot and shift boot if there is any signs of aging. In the long run its cheap insurance.<br />With the outdrive out of the way the engine will pull cleanly and you wont have to worry about damaging the splines. <br />You will have to align the motor and drive after you are all done, no question.<br />You may want to check the type of spline shaft you have, some of the older ones have a groove cut in them for an O ring seal and if you put that 300Plus hp monster on there it will shear the shaft.

 

[Patrick123]

Re: Engine Swap - Mercruiser/Chevy

Hey.<br /><br />I did almost the exact same thing you are doing. 77 Fiberform 18'/Mercruser, had the outdrive rebuilt, built my own small block Chev and put it in, it's great. Basically it is just a normal 350/4 bolt 8.75:1 with a marine gasket set/freeze plugs and marine cam with the marine bolt ons. <br /><br />Like you, I was really careful to not mess with the engine mounts on installation but I decided to have it aligned anyway. I thought since I didn't mess with it it would be close enough it would be a "while I wait" job. It took the guy an hour though, I watched him work on it in the parking lot, the front of the engine was high somehow, so it was still off. It was only like $60 for 1 hour shop time I think it was worth it personally. The tool to do it yourself is like $70, but I just felt better having someone do it that knew exactely what they were doing.

 

[Patrick123]

Re: Engine Swap - Mercruiser/Chevy

Oh also since I had unhooked/moved around/played with the throttle cable he also adjusted the "throttle tension." I never was too clear on what that was but he made it sound important.

 

[anesthes]

Re: Engine Swap - Mercruiser/Chevy

I'd check your alignment anyway.. And like he said, its easier to yank the motor out with the outdrive removed. More importantly, its easier to put back in..<br /><br />That seloc manual blows.<br /><br />I'm almost done my I4 to V8 swap in my 1986 chris-craft.. Toughest part was making some stringers to mount up to.<br /><br />Your power/torque sounds wild. Dont break anything!<br /><br />-- Joe

 

[searaysteve]

Re: Engine Swap - Mercruiser/Chevy

Thanks for the suggestions.<br /><br />Aggreed that removing the drive and having it alligned is the way to go; Been around long enough to learn that short-cuts usually end up costing more time & money in the long run.<br /><br />Yes, the Seloc Manual does seem to be lacking.<br />Already have 'Small Block Marine Performance' by: Dennis Moore; what other detail manual do you suggest?<br /><br />Motor Suggestions?<br />Motor is a 360" SBC (350 w/ .060" overbored truck block; not wild about the .060, but there was plenty of material around the cylindar walls of this block and no other option)<br />Cam Specs:<br />.050 Dur = 224 @ intake 224 @ exhaust<br />SAE Dur = 291 @ intake 287 @ exhaust<br />Valve Lift = .450 @ intake .460 @ exhaust<br /><br />My understanding is that w/ the type I Mercruiser you do not want to idle above 700 RPM's as to avoid shock/stress to the drive when shifting.<br />I'm not opposed to swapping the cam if desired but want to try as is first.<br />One suggestion is to start motor in gear to avoid shifting stress. Input welcome???<br /><br />Need all new exhaust on this boat also.<br />Originally was equipped w/ rear risers.<br />Plan on going w/ center risers (Osco probably?)<br />Debating using the current Y-Pipe through-the-prop or going w/ a through-the-hull.<br /><br />Love the sound of a well built motor, but even when I was young did not like the outrageous NOISE of glass-packs or straight exhaust.<br />Don't want to 'choke' the motor, but do want a somewhat comfortable ride.<br /><br />Through-the-hull w/ marine mufflers maybe?<br />Cost is always a concern of course.<br /><br />Sorry for the long post<br />Steve <br /><br />P.S. Anyone have any experience w/ Konrad outdrives?

 

[anesthes]

Re: Engine Swap - Mercruiser/Chevy

I'm not a boat wiz, but I've been working on SBC's for a loong time.<br /><br />

<br />Already have 'Small Block Marine Performance' by: Dennis Moore; what other detail manual do you suggest?<br />

I don't know really. What info are you trying to get? My head is filled with race car knowledge..<br /><br />

<br />Motor Suggestions?<br />Motor is a 360" SBC (350 w/ .060" overbored truck block; not wild about the .060, but there was plenty of material around the cylindar walls of this block and no other option)<br />

I've run 14:1 compression on .060 overbored blocks, coming through the traps at like 225F. You should never run that hot, and you'll run what. 9.5:1 compression.. Don't worry about it.<br /><br />

<br />Cam Specs:<br />.050 Dur = 224 @ intake 224 @ exhaust<br />SAE Dur = 291 @ intake 287 @ exhaust<br />Valve Lift = .450 @ intake .460 @ exhaust<br />

Thats like a 600-650rpm cam.. 224/224 is nothing, and the lift is like emissions variety. As long as your carb is in good working order, you should be fine. <br /><br />My current street/strip car is running 224/230 @ .502/.510 and idles fine at 650 if I want it to. Even when I added the supercharger, I only upped the idle by 100rpm.. (and this is a 550hp motor)<br /><br />

<br />Love the sound of a well built motor, but even when I was young did not like the outrageous NOISE of glass-packs or straight exhaust.<br />Don't want to 'choke' the motor, but do want a somewhat comfortable ride.<br />

With emissions requirements now, and complaining passengers its getting tough finding ways to quiet things down without stealing 50hp here and there.. Shouldn't be an issue with a boat. <br /><br />

<br />Through-the-hull w/ marine mufflers maybe?<br />Cost is always a concern of course.<br />

Un-educated on this but I'd like to find out what you end up with. I have the merc Y-pipe right now. Wish I could run headers right out the back but. That'd get hot and be loud.<br /><br />-- Joe

 

[searaysteve]

Re: Engine Swap - Mercruiser/Chevy

anesthes<br /><br />Thanks for the reply<br /><br />Sounds like you may be a wealth of motor knowledge. I'm an old gear head from high school daze and had built a SBC for a '71 Camaro that have had since '82; sorry to say I just got ready to move past the car and wanted a boat to put this motor in. <br /><br />Yea, you're accurate on my compression; about 9.8:1. And yes I'm confident the block and internals are stout enough. (maybe too much)<br />Had the block line honed, mains are 4 bolt w/ studs, rotating assembly is balanced, hypereutectic pistons, heads are double hump w/ 2.02/1.60 s/s undercut valves, quality double springs w/ guide plates, and hydraulic lifters.<br /><br />Preface: All pertinent parts WILL be Coast Guard Approve; I maybe crazy, but not stupid.<br /><br />Excuse the rambling, but the questions I'm pondering are:<br /><br />1: Am considering using a Weiand Stealth aluminum intake that I currently have. Boat will be fresh water only, any thoughts?<br /><br />2: Carb: (marine of course) Am kinda partial to the idea of a Carter. Have always run w/ Holley and am not adversed to Q-Jets either. Suggestions?<br /><br />3: Exhaust: Stick w/ the Y-Pipe going through the prop, or will that choke the motor?<br />One school of thought I have heard is that a through the prop exhaust can decrease back-pressure because the cavitation from the prop causes a vacuum. ???<br /><br />4: RE: the manual<br />What is the best Stern Drive Manual for general/detail reference; the Seloc seems ot be just so so.<br />BTW: 'Small Block Marine Performance' is excellent for basic motor suggestions.<br /><br />Anesthes, sounds like you have a really fun little street/strip car. I realize that is off topic, just curious.<br /><br />Thanks<br />Steve

 

[SeaMasterZ@aol.com]

Re: Engine Swap - Mercruiser/Chevy

couple of thoughts ... SBC is just about the most reliable and easiest (and CHEAPEST) motor to really lean on, you can max out a SBC and still have a turn the key and start everytime dead reliable motor ... 400s are good torquers, but dont like to spin too fast ... but a four bolt main 350 should really rock, and I have read about stroking them up to pretty outrageous levels ... but as usual I digress, the 350 with a supercharger on it would go go go, 400 hp or better<br /><br />aluminum is ok IF shes fresh water cooled<br /><br />if not, salt will eat away the aluminum, the resultant aluminum oxide (the ummm, sandpaper stuff) will total your engine<br /><br />trust me on this, I bought my uncles boat, the Seacraft Seafari - chewed up from the Dominator intake dissolving<br /><br />raw water feed, beware ... even brackish water can git ya, but if you are in a salt free environment, go for it!

 

[kdmiller8251]

Re: Engine Swap - Mercruiser/Chevy

Hey:<br /><br />Just read through this post real quick but didnt see too much mention about the outdrive... Remember what ever you do to that engine, I hope the drive will handle it..... Drives aint real cheap nowadays and I would hate to see you bust one up ... Good Luck<br /><br />Tallman

 

[anesthes]

Re: Engine Swap - Mercruiser/Chevy

<br />Anesthes, sounds like you have a really fun little street/strip car. I realize that is off topic, just curious.<br />

I've had a lot of projects.. My main thing right now is an 89 firebird. Fuel injected, supercharged, 355. Around 550hp at the flywheel, and good for 11's if the tires stick. It has NOS too but I'm scared to use it.<br /><br />My boats going back together tomorrow if I can figure out how to get the rusted, frozen gimbal bearing out. Might have to yank the motor again and swap housings.<br /><br />-- Joe