tomcei

Are there any draw backs to using one?

IRONMAN

$$$$ More $$$$$ and you probably should run closed cooling with one. A pair would be awesome in a 28 - 32 cat though.

tomcei

Chris, is that to reduce the corrosion factor?
I was looking at a used 572 all aluminum set up with external oil system and all the goodies.

MYSKATER32

I have a pair of 600 inch all aluminum Donovan block engines in my 32 Skater.What would you like to know about them ?

tomcei

Basicly wondering if there are any additional things to consider
when looking into this combo.
Example: I've heard the compression ratio can be higher and still run pump gas.

MYSKATER32

I can't answer that one,You'll need to talk to some professional engine builders about that .Mine are 13 to 1 compression so i just run 110 race gas.I understand that aluminum heads allow you to run a little more comp. because they absorb some of the heat from the compression stroke which causes detonation.Although the blocks are aluminum they still have cast iron sleaves which contain the heat in the cylinder. Now if you had an all alum.cyl like a water cooled motorcycle that might be a different story.

KAAMA

iTrader: (1)

A friend of mine has a 38' Top Gun Cig with a pair of supercharged 580cid Donovan blocks that were rebuilt/refreshened about 1 year ago by Dave Wesseldyk---no problems. They like using oil thermostats to help control the block temps, condensation, etc.

articfriends

iTrader: (1)

I have always been told that a aluminum block motor in a high hp app built identical to a cast iron motor gives up 20-50 hp due to cylinder distortion,liners moving/deforming,cap walk etc,the only reason for using one is weight savings. Aluminum heads usually allow for 1/2 to 3/4 of a point more compression on same exact octane due to heat dissipation,Smitty

tomcei

That all makes sense. I wouldn't think that the Alum. block would save all that much in weight. I suppose in a race situation any weight matters.
What do you think the differents in the iron vs the Alum. is?
(block only)

stevesxm

smitty,
ive never seen one of the donovan blocks but the al blocks that i have built were designed comprehensively differently that an iron block... perhaps for the reasons you suggest. i would GUESS that if you just cast an al block IDENTICAL to a iron block you would probably be right but the ones ive worked with ( all euro and cosworth stuff ) give up nothing... and the weight savings is substantial and they are easier to cool etc... an all around good deal in my opinion... having said all this, i have never built an al based american style v-8.

in a pure racing application its a "must have" but in a hot rod marine application my suspicion is that the cost benefit/hassel analysis would fail. but that is pure speculation on my part never having actually done it. and whoever suggestedthat closed cooling w/ corrosion inhibitors would be requirement is most probably absolutely correct