Chevy 350 Counter Rotation Conversion Tech

Hey guys! I'm new to CCfan.



I am hunting for Counter Rotation Conversion Tech



Broken engine / waiting on my replacment / studing what I will need to do to convert.



My boat is not a nautique       But a few of the Nautiques have many similar features (PCM Chevy powered / counter rotation / Velvet drive). The guys here at CCfan are a great bunch. I hope yall don't mind me hanging around asking a few questions and picking up on the learnings of other fellow Ski boat owners. Here are a few pics of my boat.



























My boat is a 1984 299 Dixie Super Skier

(Sky blue metal flake with some teal and silve sparkles / off white cap / Matching fiberglass metal flake swim platform ) I bought it on a deal ($1200) with the original (Dixie) Sportsman Trailer.

I am now working to replace the motor. ~ Counter Rotation Chevrolet 350 and was not propery winterized (previous owner).      















Originaly I thought I could pull it, nickle rod weld it, and be good to go, but nothing is ever as simple as it seems. When we welded it the block cracked internally and is now ruined.



So I'm looking to install a new marine gasket set and use my original timing gears / cam / lifters / distributor and convert an automotive engine over to counter rotation marine in an effort to salvage what is left of this summer.



My transplant canidate is a 1989 350 from a Chevy Suburban.



First point of interest:

I am getting conflicting information on the crank assembly. Some say I will need to change the crank due to the oil wick lines which are machined into the crank. Everything I find says the crank is smooth and that the crank oil wick lines are cast into the front and rear main seals ~ Thus the reason why you install the corect counter rotation seals. I have these on order from SkiDim.



Second point of interest:

   A few sorces are listing the rear most exhaust manifold hole as being offset on the 1986 and up automotive engines, thus my new PCM manifolds may not fit. I can swap to my original 1984 heads or drill and tap a new rear hole. Others say they are a direct fit and their is no issue. ???   



I am aiming to pick up this suburban engine next week obviously this will answer many of my questions but mean while all I can do is study, research and plan.       





Please correct me if I'm posting in the wrong spot or overlooking the obvious. I've done some searching with little / no results.



Yes ideially I should just buy / build a new engine, but I'm trying to keep cost down while the economy / job situation is sketchy.   





PS: The 89 Suburban is EFI ~ I considered an EFI conversion too, but that didn't seem like anything quick or easy. Installing an O2 sensor in the stock exhaust manifold has me stumped.     

Get an estimative on the cost of doing such convertion...
I'd switch over to a PCM 1.23:1 transmission to keep propeller rotation a put the engine as is. You'd need a new prop anyway.

Another option is to put the engine as is, and turn the oil pump on the Velvet drive and switch to a LH prop and go. The RH rotation hardcores wont like this option, but you might consider it.

what about the heads? are his current and 1989 heads the same? bores? piston cleareances?

whitfield, do you have any experience wrenching this engines?
I believe there are more than the crank issues and oil whick lines to consider, such as pistons, bearings, machining etc etc. It not only depends on your budget but in the amount of time you're willing to spend on it. You dont know how much it will cost neither the time it will take.

PCM tranny and prop around U$D1800. plus you have the 1:1 and prop for sale. Time involved a week???

reversing the oil pump and switching prop cost U$D350, time involved 2 days?

it's up to your willing.

I've missed this summer, but I'm in no hurry. Now I'll get time to work on the interior too.   

Lots of time cleaning sandblasting and detailing. Parts are coated with Sherwin Willams Sherkem industrial heavy equipment paint (good stuff and under $50 per gal here). I've got the engine converted over to counter rotation using my existing parts. My old engine looked new inside. No wear, no sludge, no rust. Pulled my cam and marked my lifters, reinstalled with no issues. I did take it to a machine shop and have new cam bearings installed (just for piece of mind). Only one shop would tackle this with the crank and rods still assembled ($80). New counter rotation main seals installed. New 1-piece oil pan gasket (Fel-Pro brand very nice stuff). It took a little work to adapt my Edelbrock performer intake (that was on my old motor) to the 89 EFI motor. On the 89 model EFI 350 (4) center most intake bolts are drilled at a different angle then the older modles. With some creative engineering that is now overcome too.

So far I'm just under $500 not including the new manifolds /risers and gaskets.   

Looking to install it next week and hope to get in a few late season sessions.

                   

Roger(UK) is right about the pistons. Many have a slight offset as I'm sure you know and will knock and slap if you don't turn them around. I knew this in advance, forgot about it when I put the engine together, and found myself with yet another bilge cleaning opportunity.   

Of course I'm covering my eyes and plugging my ears knowing this is not the right way to go...

Can the piston pin offset of just less then the width of a penny make it rattle and possibly self destruct. I guess that is one of those things I'm gonna have to smoke over and make a decision on.

     

I had a quick look at my 02 350 vortec and the difference looked about 1/4 inch from one side to the other, so around 1/8 offset will check again later today.

If the old RH block and the new one are still standard bore/same there are adapter plate that convert 1 piece oil seal blocks to old 2 part seal,which will let you run all the old RH assembly with a light hone and new rings good to go,think it lets you use the newer sump.

The other thing you may need to check is the CR as the old will be flat top and may push it up a bit from what you have,but more Hp but not too high for the gas we now have.

Which moves on to the flywheel,If you run your old RH parts no problems,the newer type flywheel (I'm told by SkiDim) when used on top mount housing need the ring gear to be flipped round to mesh right.I have the same housing as you I picked up on US Ebay for my set up but still need the starter,would be great help if you can post a pic of your one showing the nose and dog gear and how many teeth it has.

All the best with the build.   

I dont want to be annoying but this is what I meant when I posted earlier.
I wouldnt run that engine like that unless you dont mind ruinning a good block.

Checked the piston pin today size shown is from inside wall of pin to outside of piston not the best but much better than my old money guess (looks like I have lost the knack now and become a mm man) hope this helps you on your build, piston still had date stamp 20th Jun 03.


Well its up to you now and go with what's best for you, as for deals we all do them, only needed one dumper did a deal on 2 to make one ended up 2 engine rebuilds and now have 2 dumpers.

There are more Ford guys here than Chevy so they do like to see us suffer a bit before help is given but a great bunch of guys, don't get this Ford vs Chevy thing but makes some good posts each way.

You may end up with a Chevy tow motor for the boat too so all good,keep going and it will all work out,

All the best Roger.

Week (2) with boat cover off...

Week 1 was spent stripping the shaft / log / strut / rudder for refresh / alignment / reseal.   

Taking a break from under side and back to working on enigne.

Working on finishing up the engine install I started last year and cleaning up cobbled repairs / bandaids from previous owners. So far install is going smooth.


After~





Before ~





Looks like I will need to find a suitable replacment marine carb and metal fuel line very soon. I'm also in need of updating my raw water pump hose line and routing. I purchased a new strainer from Ski Dim as mine did not come with one. We put in 1/4 mile down from the fall line / rapids at low tide (shallows) lots of sand and silt if you get out of the ditch. Hopefully the strainer will keep some debris out of the block. As wifey and friends seem to cut corners on occation.   

Hang ups right now are:
      Funky throttle linkage bracket at housing and ball on automotive carb is too small for the marine cable fitting. I'm budgeting for a replacement Marine Holley or Quadra jet but want to hear it run first.

Second hang up is my 3" exhaust hose will need to be replaced soon. This stuff is uber expensive and the cast elbows I have inplace now are unsightly rusty ugly. Is their agood source for reasonably priced 3" mandrel stainless elbows and rubber fittings?       

Thanks Gary ~ Somehow I missed them on Summit.

I'm thinking (2) 90-deg + (2) 60-deg + (4) 10" - 12" sections of 3" exhaust hose should do the trick and help to clean things up.

Has anyone on here played around with getting the custom exhaust shops to bend a set of S's I know they do not use a Mandrel bender but many now offer stainless for the performance diesel crowd.

Michael,
Wherever you end up getting the elbows, make sure the stainless is a 300 series and not the 400 series which is the cheaper "muffler" grade.

Michael,
Yes on the 304.

The Trident parts are nice but pricey. I really don't feel you need to use them. Remember they need to be clamped off to hard pipe so you'd end up with short pipe "couplings". Why not just put the exhaust hose back in like the original?

8122pbrainard wrote: Michael, Why not just put the exhaust hose back in like the original?

I'm not exactly sure what original was. I think from what I've seen most Nautiques just run flex from the risers to the transom. I might could get away with that ~ What do you think?


Currently I've got (4) rusty cast iron mandrels joined with short sections of wire reinforced 3" exhaust hose.

I feel the current exhaust set up with it's miss matched hoses and random clamps more resembles a kindergarden craft project.

I might try to cean it up sand blast and paint the old cast mandrels and replace with all new hose. I'm looking for somthing to compliment the under hood refresh. Cleaning up the exhaust is one of the last steps under the dog house.

Added boat pics to 1st post.

I'll look into the all hose option.

No sign of mufflers on mine or any of the other (4) Dixie 299's I've found yet.