At this time, we felt like for only about $1,500 we could drop in a motor and only have about $7,500 invested in the boat which was still about $4,500 below what the next comparable boat we found cost.
For the motor, I turned to a local engine re-manufacturer. Even tho I read online at the Sea Ray Owner's Forum that these old Sea Rays (ours is a '79 SRV260) were underpowered with a 350 I decided to go with the same sized motor again. The main reason(s) were that I knew that engine would fit, I had some parts I could save off the old motor, and I knew the outdrive was up to the challenge.
Tip: When you change the type of engine in your boat (IE going from a 350 to 454) you have to re-gear the outdrive are geared for the torque curve of the engine its coupled to. This can cost around $1,000 to have someone do this for you. Additionally, too much additional HP (an Alpha can only handle about 300hp) and you need to move to a Bravo outdrive ... which is even more money!
I should mention here too that there are differences between automotive and marine engines which I will talk about briefly as there are safety considerations. (And before someone leaves a comment flaming me for being an idiot and how I'm going to blow myself up.)
As far as I've ever been able to find out there are no differences between a marine and automotive block, heads, pistons, or intake. You will find people who sell them and mark them up accordingly but I found at many stores (in person and online) the marine part numbers list automotive equivalent numbers as well. The biggest difference it seems is that the marine engines get an enamel coating to help resist rust which you can do on your own for cheap with a few rattle cans.
The only thing I did have to specify was that I wanted was a different cam shaft. A boat needs more torque at lower rpms to overcome the friction of the water to help get on plane, etc. This is also one of the many areas where the RV and Marine world seem to mesh together (the other big one is plumbing related stuff). They installed what is called an RV Cam which is a high torque / low RPM cam profile. As you might imagine, an RV is big and heavy and likewise needs a similar profile to what a boat needs to get moving. After crawling a bunch of sites I found that many off-road and truck owners also use this type cam to get the torque they need.
The oil pump I bought was a regular automotive pump and I used a pickup with a steel sleeve instead of a plastic one for durability. I could have used a high performance oil pump but I read some of them pull oil too quickly and the pan can dry up waiting for the oil to make its way back into the pan.
With the long block out of the way the accessories are really where boats and cars differ. By law, Marine products must be spark proof. The reason for this is that most engines are in an enclosed area where gas fumes can be trapped and a spark could be a very bad thing.
I should also mention there are marine gaskets as well. Some are cork and others don't seem to be any different than the automotive equivalent; I had the set that came with the long block and a marine set I bought to compare. I've noticed that racing gaskets seem to be very similar to marine gaskets probably because both have harsh conditions to contend with.
Some Marine grade items I bought or had rebuilt off the old motor: starter and solenoid, water pump*, fuel pump, Quadrajet carb**, and alternator. I also bought a 160 degree thermostat. Most cars have a 210 degree but for some reason the marine engines get a lower temp one.
* I can't recall if there is a marine vs. auto water pump but I found a marine one for a reasonable price (under $100) and decided to go that route.
** A marine carb features a J tubes to prevent fuel from spilling into the bilge area.
Tip: You can use ARP bolts which will not rust on your marine engine but their torque values will be different from the normal bolts.
A final thought about marine vs. automotive is that even the exhaust manifold gaskets were the same between the gasket kit despite the exhaust on boats and cars being somewhat different!
So with all the parts purchased it was just a matter of swapping the engine... or was it?
No comments:
Post a Comment