BillK

tx,

I just filled a 400 Chevy block this AM. It is a drag race application, but I do know of guys using filled blocks in circle track applications. You only fill the block up to the bottom of the water pump inlet holes so there is still plenty of circulation. Not sure how it would work in a Marine application though. Drag race engines are not an issue, they only run 8 seconds at a time Oil temps generally go up a little on the round track engines. I do know of guys running filled blocks on the street also without any issues.

I would have to sonic test the bores first to see how thick they are, then make the decision.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

picklenjim

Yes I have.I have a mark 4 block which I had dropped a valve in and cracked a cylinder.I had a sleeve installed in that cylinder.It is bored .100" over(4.350) and I run a Lunati 4 1/4 " stroke crank for a total of 505 cu.in.'s. I filled the block about half way up with Moroso Block Hard as you described earlier one side at a time on a engine stand with the cylinders turned straight up and down.The machine shop recommended it to add stability to the block.These blocks are thin at the bottom of the cylinder between the cylinder and the camshaft area.I've been running this engine in my boat now for 8 years without a single problem.It runs at about 148-150 degrees with a 140 degree thermostat. I think before it might have run like 143-145 degrees.So it runs about 5 degrees hotter now which is not enough to cause any problems.

fireboatpilot

I think it's apples and oranges gentilmen. Drag racing engines and marine engines run nothing alike. Maybe a circle track car, MAYBE. I think you answered your own question when you said filling is for a tortional value increase. Drag cars flex when under a tremendous load thus pulling the block apart and twisting. I've seen the sidewalls pulled out where the engine mounts bolt up. Also they can get away with less coolant due to the shortened run times. I don't think that a marine engine is under the extreem side loads a drag car is and the run time are quite longer needing as much coolant flow as possible. My opinion is it's no good and doesn't compare or apply.

tx911

Thanks Jim, that is what I needed to know. I am using a gm block, and at the bore I am at it is pretty thin at the bottom of the cylinders. My builder was just not sure if it had been done on a marine application. He likes the Moroso product also.

picklenjim

I wouldn't recommend to do it if you have a good block.I only did it because it was a patched up block.However I guess I got lucky beings I haven't had any problems with it.

tx911

My block is fine, just at the large end of what is a acceptable bore for the block.

BillK

TX,
My only issue with the Moroso product was the fact that they wanted you to wait 14 days before doing any machining. I also did not feel that it mixed very well compared to the Hard Block brand. With the hard block, you can actually fill the block after machining if you want because it does not expand or "move" around as it sets up. Its been quite a while since I tried the Moroso, so the formulation may have changed but it used to move around quite a bit for a long while.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Sledge Hammer

You might want to go over on performanceboats.com and post the question. I have seen a number of the jet boaters comment on filled blocks. Perhaps they were drag race applications only, but they might be on lake applications.

ezstriper

I would not run a filled block in a reg boat app, not enough cooling in the lower portion of the block after running extended periods of time...fine in drag racing....both car and boat..as only run short times...Rob

BadDog

Many marine engines are running around with a mud and sediment packed block. Pull the heads off a and look down in the block of a boat that has been run in river or muddy bottom lakes. There will always be a cerain amout of crud in there and depending upon the depth it could have a change in cooling.