Thunder Struck

My F311 finally gave up an engine on the weekend. Pair of 420's, B&G trannys, TRS, 852 hours and it finally thru a bearing. No major distruction here but it is time to do the rebuild thing.

What I need help here on is web sites that I can reference on the internal components of the 420 for that year. I would like to have them worked so that I can get a reliabe 500+ out of each motor and get another 800 hours.

All suggestions welcome.

I have previouly gone under the handle of Wild Horses. I cannot remember my old password ahd my work e-mail keeps kicking back requests for a password refresh. Any ideas Liquid Asset on how I can get back access to my original profile?

KAAMA

Is your boat a 32' A/T???

Anyway, the Merc 420's came with 4-bolt main blocks, and all internal rotating parts....crank, 7/16" rods, and pistons. They have the GM rectangle port heads with the 2.19" intake/1.88" exhaust valves and also came with Crane Gold aluminum roller rocker arms. They're good baseline engines for rebuilds and upgrade mods. The only thing I don't really trust are the GM rectangle port heads that came on that engine---they are prone to cracking between the seats!

Not sure of who you're going to have do the machine work or exactly how far you want to go to achieve 500hp, but "RMbuilder"/Bob Madara of Marine Kinetics knows the old cam specs of the old Merc 420hp engine which I am sure used a FLAT tappet cam. Bob can help you with a hydraulic roller cam to help you achieve 500hp, but not sure if you'll get another 800+ hours out of a 454cid marine engine making 500hp. Also, you may consider going with some Merlin heads which flow better and are not prone to cracking between the seats. Have fun with your project.

Thunder Struck

Kaama

No AT, maybe one day though. I have an '89 Formula F311 called Wild Horses. I have owned it for 7 years and put LOTS of hours on it. Boat is very well kept. The engines have performed flawlessly the entire time. They were detuned to run on regular but I am using it less and less and would like to get everything I can out if it over the next 4-5 years. The intent is to flip it then.

I am located just north of Toronto in Ontario, Canada so the work will need to be local. I may contact Double R Performance to discuss options. Thanks so much for the input.

Has anyone had experience with Double R on complete engine / tranny overhauls? Out / Rebuild / In w/ warranty is what I will be looking for. One stop shopping is the only way I will go. I have been down the other road too many times on other projects.

Cheers,
Trevor

Griff

The stock cam is a Crane #132561 (flat tappet)

.530/.551, 228/263, 114 lobe sep

shawn

I have a pair of cams out of HP500 Carb motors for sale $125 each. There are two sets of heads and valve covers off HP500s in the swap section. Lifters, springs etc and you are good to go.

Shawn

Whiteknuckle

If you are looking for Merc part numbers and drawing of internal components, visit the BAM website. Just feed in the info of your engine and the year and a parts sketch will appear for each system you choose. It sounds like a nice project. Good Luck!

Thunder Struck

Thanks everyone.
I have a bit of time to think about this one as we just built a log home and are starting up a horse farm. Kinda tough to tell the wife we can't buy stalls due to boating!! She most likely will sit out next summer.... the boat that is.

http://www.loghomereports.com/forum/...p?TID=105&PN=1

I will spend this time looking at build options and finding the right company to do all of the work. My initial thoughts would be bore 30 over, deck the block / heads. I would like to keep most of what I have, so a valve job on the heads once they have been checked out. Will go to a hydraulic roller cam and new roller rockers. What should I do with the compression ratio. What is the current compression. Should I stick to the same cam? Both engines have never been touched other than plugs, wires and a starter in 850+ hours. I run the boat hard but responsibility. Always changing the oil etc. Does anybody have ownership experience with this motor in doing performace upgrades.
Please keep the ideas coming.

Trevor

Thunder Struck

Ttt

Pat McPherson

If you can afford to spend a little extra, I would replace the stock heads with a set of large oval aluminum heads. Edelbrock has a nice marine package for $1500 per set.
http://www.edelbrock.com/automotive_...t_bb_rpm.shtml
I've spent as much as $1000 having cast iron heads reworked. That won't happen again...

birdog

Your heads are fine.....jeez guys, He got 852 hours outa those "crappy" heads..You know, The ones Merc ran on all the HP stuff for Years.... 500 hp doesnt need to spend thousands on trick heads...
They do not like to be overheated though !

I wouldnt think 500hp would be hard to get from a 468 with a decent roller cam.....no ?