Looking for bare engine block with pistons

[Lou C]

OMCs had both one piece (1985-1990) and two piece manifolds/elbows (1991-1998) on the 4.3 V-6s. In fact the 2 piece is easy to find because Volvo used OMC designed parts when they went to the SX series drives in 1994 and on up. So you can replace those cracked manifolds/elbows with Volvo Penta 2 piece V6 manifolds, or even the aftermarket equivalent of them which are widely available here in the USA. I did just that, replacing my OMC one piece units with Barr aftermarket exhaust on my '88 4.3.
What you seem to have there is the pre-vortec style of the 4.3, with the roller cam no balance shaft and one piece rear seal. 1987/88 up to about '94 or so when they added the balance shaft. You can pin it down better by looking up the casting #s on block (rear right hand side pad) and casting numbers on the cyl head, which are on the inside surface near where the rocker arms mount.

https://www.rapidomarine.com/default...ngines262.aspx
look here for information on casting #s and variations. Mine is the same vintage 1988.

 

[Westieman]

Thanks for the reply!
Indeed, the engine is a '89 and not in the same condition as yours, yet.
In fact, the old OMC exhaust manifold apparently consists of 3 pieces. There is a aluminum header ( see pic )
Does this make it a aftermarket conversion?
Also, there are anti return clappets in the Y tube. These are not present on the Y tube I got from the Sunbird donor.
The casting number is 867 I think?

 

[Lou C]

No I have seen those aluminum exhaust adapters as original equipment, as were the exhaust flapper valves. So what you need is the OMC/Volvo Barr exhaust kit for the V6. About $750 here in the USA. Which is about 1/2 the price of Volvo OE.

 

[Lou C]

You can tell those exhaust adapters are OE because of the "M" stamp that is circled, this stamp is on many cast and machined parts that OMC used. They adapt the 4" elbow outlet to the 3.5" Y pipe. Do not discard those, they are hard to find and the Volvo equivalent costs about $220 each!

PS I used the Barr kit myself, the fit was very good and no leaks, but the paint is thin, so if you go with them I'd coat them in a couple of coats of rust resistant paint. They don't get that hot at all (or shouldn't) so you can a regular paint like Rustolium (what I did) and 2 more seasons no rust....

PS
even though an OMC catalog will show the fuel pump as costing $234, it can be found much cheaper, it is a Carter Marine pump # M60201, you can also use Sierra # 18-7289. The Carter can be bought for approx. $100 US from Jegs or Summit Racing.
Hope you have the pushrod and the special cover plate used on the V6s (the pump on the V6 mounted upside down compared to the V8, hence the need for an adapter between the pump and block. If none of this can be found in Europe, you can just go with a low pressure electric pump with oil pressure safety switch.

PPS
the fact that the engine had a Rochester carb and breaker points suggests it is pre 1990, after that they switched to Holley carbs and used later on an oddball impossible to find parts for ignition system you for sure do not want. The simple Prestolite distributor will last forever and can be maintained with aftermarket points, condenser, cap and rotor as long as the weights and springs under the points plate are in good shape. They need to be oiled now and then....

 

[Scott Danforth]

agree that the motor looks to be '88-89 vintage, however not sure when yamaha switched to electronic ignition.

Yamaha used the 4.3's from GM just like everyone else did.

Balance shafts hit the automotive market in 92 and most of the marine market in 93

 

[Westieman]

Thanks again for the help! It is a pitty that we live so far apart. I am sure we could chat all day long and have some nice boating trips. However in "corona times" this might be a bad idea. Stay safe and in good health!!!
I see that NY is badly hit by the virus, so Lou C, better stay at home!
Visit the states is on my bucket list, maybe one day....

The engine I got is a mix of OMC parts and a " Yamaha badged" block. Took it apart today.
I will probably do the same and build it up a mix of parts from both engines. The block is OK but cranck has already been ground down. Bearings are not ok and are .020.
So will be using the cranck from the initial engine whitch is in A+ condition. Also the camshaft, cam followers and push rods will come from initial engine. Those of the "yamaha" are in bad shape. Engine seems to have been run with bad engine oil. Camshaft seems to peel of and some push rods are bend. Cam followers took a beating so I will discard those also.
Witness of the bad engine oil was also found in the sump: Thick sludge.

Cam bearings look bad and will need replacing, this will be a problem without the proper tools. Any suggestions?

Of course, cylinder heads will have to come apart. I am afraid that valve stems might be stuck in the guides.
Pistons are OK as are connecting rods. Cylinders will honed to eliminate small imperfections.
Would go for a Fel-pro gasket set and the Barr exhaust. Any suggestions where to order these? Took a look in the Iboats shop but could not find any.

 

[Lou C]

we are not supposed to post links to other vendors on this site, but if you go and do a search there are a good # of them. If you get the Fel Pro gasket set make sure it is for "engine without balance shaft" because there are 2 versions. Check your cyl head bolts, if they do not clean up I would replace them, APR is a good brand here in the USA. These bolts have to have sealant put on the threads (Permatex Aviation or similar). You probably already know this but I'd strongly advise getting a thread chaser and clean out all the head bolt threads in the block.
Yes too bad we are so far apart, same boat brand, same sterndrive set up and engines lol!
BTW, the Four Winns I have has been a good boat for us it handles rough water great for its size.
When my original engine blew the head gaskets and had water in one cyl I thought it was done for, but after showing pix of the block etc to mechanics I trust, I was able to do a partial rebuild of just the cyl heads.

 

[Westieman]

The treads for the cylinder head bolts, these are not metric are they?
This is Europe. Metric tread chasers, no problem but something else....
Today I took apart the cylinder heads. Found a bend exhaust valve!
Hope there are no more surprises.
Tomorrow more news on the engine front.
Outside, temperature is rising slowly so maybe Sunday I will start polishing the hull.
It does need a good clean up. I like it shiny. But this might not work out. The wife told me to get the high pressure cleaner and clean the outside furniture and do some other outside stuff. Well, you know how it is probably.
I do hope to get it finished for the summer and get it out on the water. But then there is the lock-down.....

 

[Scott Danforth]

your motor has been gone thru at least once.

.020 is is the point I would look for a different crank myself. how is the surface?

cam bearing tools are easy to make, and highly recommended for installing. a few delrin discs and a section of wooden dowel are all that is needed

nope, your motor is all SAE threads

valves are fairly inexpensive over here. then again, good motors are a dime a dozen as well.

 

[Westieman]

Not sure what type I should order
GLM58640

or this type

GLM 58480
Both are for Volvo penta / OMC
Have been looking in to BARR but they don't do kits or, I could not find any.

 

[Westieman]

Indeed Scott, crankshaft will be exchanged with the one from the initial engine although it is not so bad. Bearings are worse.
But, if the bearings suffered, so did the crank. Surface is good but finish is not. Sharp edges at the oilways.
I ordered a tool from ****auto. Might come in handy for pulling other bearings as well ( gimball ?).
I expected some valves to be bend, multiple push rods are bend so...But valves are easy to check, but what about the rockers, they are in between.

 

[Scott Danforth]

cam bearing tool is different than the jaw-type bearing tool for the gimbal bearing.

rockers and pushrods would be same as a V8. should be easy to find

 

[Westieman]

Tool comes with several different adapters. Will find out when it arrives....No problem for spares at the moment, got a spare engine to break, remember.

 

[Lou C]

Not sure what type I should order
GLM58640

or this type

GLM 58480
Both are for Volvo penta / OMC
Have been looking in to BARR but they don't do kits or, I could not find any.

it is the second style with the center elbow.
the first is for the older model V/P engines, looks like a Ford V8 set up.

BTW, in my neck of the woods the 2 shops where I order parts, will not even order parts from GLM...they are referred to as GOOD LUCK MARINE.
See if you can find something better. If it is your only choice then for sure use a straight edge and check the flatness of them mating surfaces to make sure there are no low spots. This style whether used by OMC, Volvo or Merc is prone to leaks so you have to have perfectly flat sealing surfaces and good gaskets. In fact Volvo changed their gaskets and installation procedures a few times for this reason....

 

[Scott Danforth]

Top one is an AQ series

 

[Lou C]

Yep the top is actually the old AQ style V6 exhaust. So no matter what exhaust you buy get a mechanics straight edge and check the surfaces by trying to slide a feeler gauge under the straight edge; I used a .003”, .002” which is actually less than Volvo’s spec of .1 mm which is closer to .004”.
When I had to change from the OMC one piece I thought of going to the Merc dry joint design which is superior to me because water does not pass close to the center exhaust opening, but I was not sure if the elbows would line up with the Y pipe given the difference in the angles of the down slope of the exhaust elbow. If and when I re power with a new engine I might see if an exhaust shop will lend me a manifold + elbow to see if it lined up. The Volvo exhaust fits these OMC Cobras perfect because it was designed by OMC!

 

[Westieman]

Think this is the stuff I need? NKB-OMCVO-43-CEO-4I
Indeed, those dry joint design manifolds look tempting and look very similar in angle. Technical drawings would be helpful to compare things.
In fact, we need to handle them like a cylinder head. The gaskets could be made like the old style head gaskets with copper and asbestos but these would not resist salt water long time. Even the VP gaskets, in aluminium I think; wont last long in salt water. But then, sea water eats everything. One of the reasons I prefer boating on lakes and rivers.
Have some pics of the trouble areas...

 

[Scott Danforth]

cam is shot
rod will need to be re-sized
typical non-chamfered crank hole.

 

[Lou C]

As long as that is the center riser type as in the pic above it’s correct. I didn’t actually use the VP gaskets pictured above I used the ones supplied by Barr which seem to have a stainless core and composition gasket. So far soo good.

 

[Lou C]

what I used...