311 Engine Upgrades
 

The year 2020 has sucked. Period. The end. I’ve only been out on the 311 once earlier this summer because of a exhaust valve problem... long story short... heads decked one too many times causing the valves to hang open just enough to cause reversion. The #7 exhaust valve on the port engine ended up being toast. I don’t like working on the engines in the boat so they’re coming out, And since I have these nice AFR heads and Crane cams etc sitting around collecting dust, I figure it’s time to start making some changes.

Heads are being taken down to 114cc to bring compressing up to approximately 9.25. I’ll be using 621 cams that at first may seem rather conservative but with the flow of the heads should act a lot bigger. I’ll be using Merlin intakes with Mighty Demon 850s.

I’m trying to get the fuel system figured out. My 502s have no provisions for mechanical pumps so everything will be electric. I thought about using a water pump with the mechanical pump provision but there isn’t any room unless I change the pulley configuration (something I really don’t want to do). My question... where to mount the pumps? I’m thinking the only spot available is on the inside of the stringers opposite the sea strainers. I had also thought that maybe I could modify the MPI fuel systems to work but I don’t have a pump curve for the factory pumps and it seems like it would be easier to just run some Mallory Comp 140s. Does anyone know what the fuel pickups in the tank will support or will I need new pickups? I was thinking -8 AN for the entire system.

The goal is 600 hp... should be pretty easy to get there and be reliable at only 1.2 HP per CID. The engines should come out next week barring any weather issues.

Good luck with the upgrades Tom. That old girl will run really well. Very similar setup that we had in the Monkey...sort of :drool1:

Thanks Chris! I’m looking forward to next season. Hope you’re well!

Good Luck and keep us posted on the technicals and progress.

Thanks Tom!

How’s your 311 making out? Enjoying the Gulf?

Sounds like some pretty decent upgrades Tom. I think it’s safe to say this year has sucked in many ways. But when your motors are done atleast you’ll be fresh

Faster than I expected...78 mph gps (2 people 3/4 fuel light chop) with the "economy" 4 blade props. I have not even tried the top speed 3 blader's.
Starboard Bravo seems to shift hard in reverse (when warmed up) but I think its the linkage/cable...as lubricant looks clean and no water.
Dock space is available!

Tom, I always hate to hear about engine trouble. But it seems like you have a solid plan to make an improvement. That big girl is going to be breaking the 80s when you are done.

Thanks Hunter. We’ll see what happens. I’m eager to start the work but of course now it looks like rain for days lol. Figures. In addition to the engine work, I’m also going to tidy-up the bilge as well as paint. The battleship gray has never been a favorite for me. I’m also going to get rid of the “trailer-style” harness connections that are buried in the wiring. I’ll probably use ring terminals and junction blocks as replacements. It’ll be nice looking, functional, and remove some of the little electrical gremlins that seem to pop up over winter’s layup. while out, the transmissions will get some love too with rebuild with extra plates and a new damper for the starboard engine (port was done last year).

It’ll all be a project and a half but what else is there to do right now?!

We just got rid of our 27 contender and picked up a 31 with a blown hpdi on the starboard. Got it all re wired, sound system, plotters, radar, all the stuff done. Waiting on machine shop to finish sleeving the block. We decided to take it to the creek on 1 engine.

You still have 1 good 500hp engine. She should make it on plane with that lol

My good buddy said to put it back together and putt putt on the bad engine. Dropping valves seems counter productive, lol.

And with my luck lately, I’d lose the starboard motor just creeping along to the sandbar.

Nice going on the 31!

I can appreciate your patience. I'm eager to see how she turns out. Going to be a neat top end set up you are going with.

Slow start to everything. Weather, work, family.

I'm hoping I have the injection parts removed soon so I can start selling those off for extra funds. If anyone is interested in a nice stock MPI set-up, I'll make a good deal on everything. It'll be everything from the fuel lines (after the separator) to the intake manifold including the wiring. I'm going to keep the distributors and coils but the rest goes. Will also include the wiring to the helm. New injectors from BUP in 2019 (these are really nice and cost me over $1200 to do both engines).

All MEFI 3.

Sounds like a good recipe for 600 hp to me. As far as the fuel pump location, your stringer mount is a good spot and low as possible. I have had great luck with the aero motive m-1000. Good luck with all of it...That is going to be completely different ball game when you add 400 ponies to the props.

The fuel pickups in our 88 311 are rather small pipe thread in size i'm thinking 3/8" npt female at the tank fitting. Let me know what you end up doing for tank pickups I think you will need to upgrade from stock to support 600hp.

Thanks!

I was hoping to avoid going into the stringers to mount them. Space is already very tight upfront with the TRS set-up. I guess I could mount the pumps more toward the stern, maybe? That's an idea!

That Aeromotive m1000 is think is going to be way overkill not to mention over $1k to do two engines! I was leaning more toward the Mallory Comp 140. I've used Mallory in other projects for years and been happy. Now if someone has a couple of used pumps for sale at the general 50 cents on the dollar used parts rate, I might be tempted! Any advice is appreciated of course.

I figured I would probably need to open them up. I was going to pull the anti-siphon valves to start, then look at the pickups. How has pickups for sale? I'm pretty sure I could make my own, but if something is available with less work, I'm all in.

It's always the last one...

Beautiful Labor Day weekend... could hear some boats getting on it pretty good from the house and figures that I'm stuck here working on my boat.... I'm down to removing the last header bolt so that I could get the outside starboard header off. Everything is so tight in this boat because of the MPI crap and I was looking forward to having it off so I could reach the bolts on the offshore mounts. "Strange... not a socket-head screw." I feel the bolt really well and realize that someone has used a standard header bolt on. I guess they ran out of stainless socket-head screws? Great. Got a socket on it, not budging. Breaker bar, rounded off the head.

F----!!

So this job just became a few degrees harder.I would have had both engines out over the weekend had I not run into this. I decided the rest of the holiday weekend wasn't worth sacrificing so I finished up what I could with the intention of finishing the removal this coming weekend.

The Gen VI 502 MPI is not a good fit in these boats. Well, in my boat anyway. The accessory layout especially on the starboard engine doesn't fit well with the layout of the stringers. I will need to rethink some of this when it goes back together. I hear guys saying they can have their engines ready to pull in under an hour. Not on this one! Hell, It takes a good hour just to be able to get to the mounting bolts on one engine and that's using an impact.

I have been really trying to come up with a fuel pump idea and thought about using a mechanical pump similar to the Gen-V but the accessory layout makes that impossible. I'm open to ideas on how to put this back together to make it easier to work on.

Thanks for letting me rant.

TZ

These are not rants, they are road maps for the rest of us! Keep going!!!

Thanks Tom!

I'm sure my neighbors loved my "ranting" about the header bolt the other night! I was a little vocal about it lol.

Yup, my neighbors hear a different vocabulary...last week I dropped/lost a bolt into the water, and let loose a tirade!

Ahhh.... The joys of boating!

This few times a week it seems :)


https://cimg8.ibsrv.net/gimg/www.off...dcd07f6db.jpeg

HAHAHAHA!!!!

Exactly!

Can't stop laughing...

Rain... argh.

And this is interesting.... why the heck am I seeing ads for women's bras within OSO's advertising? Did I miss something? I know I've gained a little wait with this permanent work from home thing but??

And more importantly... this!

HAPPY BIRTHDAY TOM!

:happybirthday:

I'm not seeing those ads and thanks...I don't feel a day older than 50 (and I'm 61)!

www.adblockplus.org free version on your phones and pc’s works great.

Happy birthday ! Hope you get some replacement 10mm sockets. Lololol

One’s out...
https://cimg3.ibsrv.net/gimg/www.off...a20369a11.jpeg
Port 502 MPI on the way to some upgrades.

I like that 2 post style over the traditional A frame. How did you finally get the exhaust bolt out?

I like this gantry. It works well and seems to be built fairly well. I have power lines around the house so being able to lower it was a must. A standard A-frame wouldn’t work for me.

I have t gotten the bolt out yet. The engine is still hanging from my hoist in the garage.

Some updates...

Starboard is out and in the garage:


https://cimg3.ibsrv.net/gimg/www.off...a0c744e04.jpeg


The top end is off the port engine. I have not removed the valve to see what’s up but it definitely definitely put a little dent in the piston. Oops. Fortunately, it’s livable.


https://cimg7.ibsrv.net/gimg/www.off...e4a8b1940.jpeg

Leakage was acceptable once I had the valves adjusted (except number 7) so the bottom end is good. Time to start the rest of the disassembling so new parts can go on.

Your 311 is able to fit between the uprights of the harbor freight gantry? I was thinking I would need a longer top beam.
nice work! Good luck with the build, I’ll be checking in for progress pics

It fits but it's really close. I'd say that it has about two inches per side in the stern. The widest area of the boat is near the middle of the length. If I had a 357, it probably wouldn't work.

Ideally I like to build one with uprights mounted against my walls and span length of garage. In the long run would take up less space,but would need a forklift to assemble.
I’ll probably go with the harbor freight one in the long run,not like I know anyone giving away I beams so I could build it cheaper. Lol

What hydraulic steering is that? Is it add on or full hydraulic to the helm?

Tyler, that’s a Latham system, full hydraulic.

F’ing bolt lol.

I tried a few things last night to remove it. It just rounds it off more and more. I’ve thought about getting a set of bolt biters to try taking it off but they’re expensive. If I can get my MIG in there I might try welding a bolt to the one stuck in there. I don’t think I can get my angle grinder in the space.

Use the right fasteners!

I have most of the starboard side torn down now. I just need that bolt out of there!

Hopefully if you weld to the bolt it doesn’t weaken it to point of braking when you start cranking on it.if you can grind the head off will it leave enough to grab on to

If you can post a picture of this dreaded work area, we may be able offer some brainstorming. I've had good luck heating with a torch and dabbing it with beeswax.
Many bolts have broken heads. Weld a nut to the remaining stud to get it off once engine is out.

Any way to get a die grinder in there to take the head off? Be it a small cut off wheel used sideways and grind it a little at a time, or even a burr bit.