Alm. Blocks
#12
Registered
Platinum Member
Stick with Iron. THe corrosion factor isn't worth worrying about.
Stick with 598 also. You will make just as much power as the 632, and it will last longer.
Good luck.
Stick with 598 also. You will make just as much power as the 632, and it will last longer.
Good luck.
#13
Registered
Im building two LS7 all aluminim small blocks for my 30 skater go closed cooling and dont woory about corrosion i had to keep the weight down so thats why we went this way they are 460 cubic inch 700 hp all day long efi naturaly aspirated cant beat it should be interesting
#14
Registered
My Experience
For you experienced engine guys out there ... What would be the pro's and con's of using a all aluminun motor in fresh water. Except for the price. Would they have as much durability as iron blocks in a N/A 598 or 632. Would the weight savings be notable in a twin 40 ft V
In fresh water there is little to no downside using an open loop aluminum block. Salt should be closed loop.
They are as, or more durable than iron. Unlike an iron block they can also be repaired when you kick a rod out of the side. This is why there is such a robust aftermarket for them - if you take care of it it can last a lifetime. The aluminum "expansion issue" was solved decades ago by companies like Donovan, Rodeck, GM etc.
(Donovan can let you REALLY build a big engine) Steve Schmidt builds these a lot.
Most prestigious builders DO offer an aluminum option for a substantial extra premium of 2-5K a block. It's not always on the parts sheet but a quick phone call will get you an already memorized uplift quote.
The weight savings are are at bout 200LB over standard big block. On a twin engine boat or a 21ft river runner this is a big difference.
The downside comes when you
1. Have to bold accessories TO it that require more than a few lb/ft of torque- you cant just let a a line mechanic jab around it- you need to be really careful hell pull the threads out- you pretty much need to helicoil all heavy torque threads.
2. Cut the check.
Uncle Dave
Laveycraft 2750 -710
Laveycraft 20.8 Sebring
#15
Registered
The aluminum between the cylinders is very thin because of the sleeves. You have to check how deep the head bolt holes there are threaded and get head studs that are longer than normal to thread into them. If you use regular studs, you'll pull the aluminum right out from between the sleeves.
The weight savings is at most 150lbs. An iron Merlin block is 260lbs and a Chevy block is lighter than that. Using aluminum heads saves about 45lbs ea. Times two for a twin engine boat you save 4-500lbs. In a smaller twin engine boat like a 30' Scarab or a 27' Magnum it would really make a difference. In my Black Thunder, not so much.
The weight savings is at most 150lbs. An iron Merlin block is 260lbs and a Chevy block is lighter than that. Using aluminum heads saves about 45lbs ea. Times two for a twin engine boat you save 4-500lbs. In a smaller twin engine boat like a 30' Scarab or a 27' Magnum it would really make a difference. In my Black Thunder, not so much.