Need New Motor

I was just told by my mechanic that I need a new motor in my 1989 Malibu Sunsetter. He told me that even though the compression is ok at 140 to 145 the motor failed the "blow by test" at 60%. I guess it should be 10% max. Anyways what should a new "Merc Cruiser" motor cost, and what should a rebuilt motor cost? I would appreciate any suggestions on possible modifications I should have done to the motor or if anyone knows where a good place is to buy a good new or rebuilt?

almost as much to replace the sunsetter...
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=63686&item=4545171 307&rd=1

(Message edited by h20jnky on April 29, 2005)

I bought a 351 for my 85 nautique from these guys last year.
http://www.jasperengines.com/mari-products.htm

That's crazy i never knew that jasper built marine engines, my dads company used to build engines for them mostly honda stuff and some other inmports i was just in one of there plants in springfield, mo a few weeks ago that is one awesome operation

I've had the engine for a year now and have not had any problems. And if I remember correctly, it carries a 1.5 year warranty.

I used to be a Mercruiser dealer. Here's a little secret: Auto engine + proper cam + brass freeze plugs = Marine engine. If the engine is reverse rotation (CW viewed from the rear) the timing chain is replaced with a gear set keeping the cam rotation the same while crank goes the other way and rear main seal and starter are different. That's all there is to it. Jasper should be fine.

Rob,
Check out SKIDIM.com.

Looks like all you need is the block, and you can switch all the components on to the new engine.

http://www.skidim.com/products.asp?dept=1013

I was checking out the michigan motors site www.michiganmotorz.com and it looks like they have some decent prices. Anyone had any experience with them? I live in Canada and I have been told that when shipping a motor over the border there can be some lenghty delays?

I am getting the motor rebuilt be a local shop - www.dandy.ca they have a lot of experience and said they can build me a top notch motor. Anyone have any suggestions for possible changes I should have they make over stock?

Not that it may not be true, but I have never seen a motor have 140 psi with 60% leakage, and I have done those specific tests too many engines. You might want to get a second opinion, before dropping a couple of grand. Can you post up the exact readings? Also unless there is a reason not to the best bet is to rebuild your current engine.

Peter

It was 140 at the beginning of last season and 60% leakage at the beginning of this season. I went out to the shop and looked at the motor with the mechanic - it was a mess. There as obvious wear in the cilinders, abnormal wear on the cam etc. The block was buldged, manifolds were JB welded etc. The motor that was in there was a piece of crap. I also was told by the mechanic who winterined it (different shop) that he thought the bottom end of the motor wwas going by the amount of blow by in the carb. At the end of the day this is going to be one huge bill.

well who ever winterized it messed up then and i would be going to them... a buldged block from what frozen water?????how does blow by get in the carb? if i was you i would go by a compression tester kit and do it yourself.(very cheap at harbor freight) i dont understand how your motor went from good looking to looking like a piece of crap? did they pull a switch on you? how long was your boat there last fall while it was supposidly get winterized? a rebuild yourself and a little machine work a few hundred dollars. honestly i thinksomeone is pullin a fast one on you and trying to get over. if you are not a mechanic i am sure you have a friend that must know a little about engines take him with you. if not post here we will help. jb welded gaskets? are you sure its not silicon?

Rob, Peter that posted above knows what he is talking about and i concurr with him, I used to race motorcycles and have done my share of compression tests as well as leakdown(blow by) tests. Swelled block most likely is a result of frozen water in the block.

Thanks Bob -I guess i need to clarify. Upon pulling the block you could see numerous issues with it that had probably been around for some time. The block was probably improperly winterized prior to me purchasing it. It was running a littly rough at the end of the season with a little smoke. I mentioned this to the shop who winterized it and they thought the bottom end was going. I took it to the shop it is at now and they concured with the first shop that there is definate issues with the motor. I purchased the boat at the beginning of last season and a shop (Calgary Powerboat)inspected it and did a compression test and said it was obviously a replaced block but compression was good. However after driving it last season and not knowing too much about boats I thought it was a little under powered. After looking at the motor in the shop I am quite suprised it evan ran properly. I believe that this motor has seen years of use and abuse and I am suffering the consequences of it.

Even still Rob, as long as the core of the block is ok then the engine would be cheaper to rebuild. I was just at my merc dealer and he had a crate motor from merc on the floor that he said was somewhere around $3500-4000. Just have a local reputable machine shop rebuild it. If you have the skills it may save you some jack if you pull it and install it.

I know the local Chevy dealer here during a big freeze sold a ton of engines. As said before, you can run an automotive engine, but it must be of good quality. Think about this, a boat is under a very heavy load constantly unlike a car.

If you had the block freeze I would not reuse it. That would bother me not knowing it were good or bad, and spending all that money on it. A good machine shop can determine that in a few minutes though by taking measurements.