Dan,

Yup. He’s in really tight with a racing machine shop, so they pushed it through. I was also able to get everything on demand. Literally everything I needed was on the shelf, ready to ship. Once we decided on a course of action, everything has been falling into place pretty smoothly. He’s got the head gaskets in hand now, and I’m hoping the rockers, as well, so the long block is on a pretty short horizon. Hell, if the weather holds out, we might have the boat in the water before Christmas. Seriously.

Thanks. Brad.

My 496 risers. I used Eddie Young's writeup.
https://cimg6.ibsrv.net/gimg/www.off...cc970b1635.jpg
https://cimg7.ibsrv.net/gimg/www.off...d03fe3a33c.jpg
https://cimg9.ibsrv.net/gimg/www.off...d2c79e4e5b.jpg

Padraig,

How to install oxygen sensor bungs. - Offshoreonly.com

Found it!

Thanks. Brad.

Ryan,

After a bit of a rethink, I am planning to incorporate them into the tilt risers I made. I'll post pics when we get them done. Work has picked up quite a bit, now that election season is over, so it might be a minute....

Thanks. Brad.

Guys,

https://cimg4.ibsrv.net/gimg/www.off...4f3fc2b3d.jpeg

Crap…! Time for a bit of a rethink on the plumbing of my tilted riser blocks, too. :picard1:

I hate it when I get ahead of the build, then realize a plan was sideways all along.

Thanks. Brad.

Guys,

https://cimg1.ibsrv.net/gimg/www.off...cb7c61705.jpeg
https://cimg2.ibsrv.net/gimg/www.off...8a664ed52.jpeg
https://cimg3.ibsrv.net/gimg/www.off...dccdcb643.jpeg

I have a plan for the riser blocks.

https://cimg4.ibsrv.net/gimg/www.off...1eaad5ef7.jpeg
https://cimg5.ibsrv.net/gimg/www.off...9e067c9cf.jpeg
https://cimg6.ibsrv.net/gimg/www.off...63192351e.jpeg

And for the O2 sensor bungs.

Thanks. Brad.

Sure is purdy, but will it work? :evilb: You sir have some talent. :D

SonicSS,

Thirty-some-odd years of making chips ought to account for something. :ernaehrung004:

Shouldn’t be any real issues with it not working. It’s just a water jacketed exhaust riser. Pretty basic function. The only thing I’m worried about now is the interior water outlet conflicting with the valve cover. Won’t know how that is going to work out until we get to that point.

Thanks. Brad.

Guys,

https://cimg1.ibsrv.net/gimg/www.off...44c6ca9df.jpeg

A little bit of progress. Scorpion Endurance Marine rockers are on order and should be in hand soon.

https://cimg3.ibsrv.net/gimg/www.off...f1fd31e60.jpeg
https://cimg4.ibsrv.net/gimg/www.off...21640da09.jpeg


O2 sensor fits snug, but it fits. Both sides have a bung. They will be welded in tomorrow, as will the elbows that correct the plumbing conflicts.

We will use closed loop to set the tune, then convert to open loop. The builder already has a base tune built that he expects to be fairly close. I believe there’s a O2 reader that transmits Bluetooth and has a mobile app….? I may go that route, just to check in on it occasionally, but I do not intend to run the boat in closed loop.

Thanks. Brad.

I am wondering if your riser block even needs a water jacket. I would think that the manifold and riser would act as a heat sinc and pull almost all of the heat out of it. Anyone ever tried it?

Snap,

I’d think it would get pretty hot while running, but it would probably cool off reasonably quickly after shutting down. That said….

I’ve gone to the effort of designing and building a jacketed riser, dammit. I’m gonna make it work! :pray:

Thanks. Brad.

Guys,

Thinking about how to purge the bulk of the air out of the fuel lines for initial population….

https://cimg9.ibsrv.net/gimg/www.off...bba6149f2.jpeg

As can be seen, I am returning the regulator bleed-off to the filter head. I have explored the option of adding a return bung to the tank, or teeing to the fuel fill tube, which would obviously make this an instant non-problem, but I just don’t see it happening. I don’t have that level of commitment to what is involved. The hose at the fill port is all but inaccessible, and getting it off at the tank has proven impossible. I could maybe tee into the vent tube, but I could see that as being problematic. If not, do tell. Otherwise….

I’m thinking about replacing this elbow with a tee, allowing for a purge line to be attached that will allow the air to escape without having to run it through the filter, continuously recycling it until the injectors consume it. I know some air will have to go through the injectors, but I’m just trying to minimize the process. Obviously the tee would be capped once purging is done.

My question is this:

With this tee open, will the pump pull fuel through it instead of from the tank? I could see it doing so at first, when the entire fuel tract is dry, so I’d plan on capping the purge line (which would be at a vacuum at this point, until we get fuel to the regulator. I’d think the pump would then put the purge line at a higher pressure than the vacuum being drawn on the tank, and the flow would reverse, flushing fuel and air out until “all” the air was gone. From that point on, at least until a fuel filter change, which would require a repeat of the purge process, the fuel tract would be fully populated and devoid of air.

Yes/no? Thoughts?

Thanks. Brad.

do you have a provision to mount a fuel pressure gauge on the fuel rail?your gonna want to watch rail pressure and make sure its steady and not bouncing.bouncing means air up there in the rail.

Sutphen,

It has been discussed, but no, I don’t have a gauge port on the rail. I have since teed the gauge port on the regulator and included the pressure sender, but the gauge is still on the regulator. Will this not reflect the pressure at the rail?

https://cimg8.ibsrv.net/gimg/www.off...9625a23b1.jpeg

The OEM fuel rail doesn’t even have a return line, so I know the injectors will eventually consume all the air in the system. I’m just trying to expedite the process a bit.

Thanks. Brad.

you think that would be the case,,we saw differently.after days of running,we finally sent the return to the tank and rail pressure was perfect.this happened on 47excalipers whippled 496's.we tuned his engines on the dyno and we knew the afr's would change,,but the swings were crazy.put the gauge on the rail and it was bouncing.
hope your situation is different,,just keep an eye on it.

Sutphen,

I am not at all opposed to running the return back on the tank, but I’m not, at this point, willing to commit to breaching the tank to install a bung, and have yet to find a feasible way to tee to the fill hose. I can get to the top of the tank, and get the fill hose loose, so that I can move it, but at about 1/4” of movement, it just hits a wall and won’t budge. I can get to the fill hose at the fill port under the gunwale, but getting it loose is going to be next to impossible. I’m pretty sure I can tee to the vent line at the top of the tank. Thinking about it, the tank should always be at neutral or negative pressure, with the tank drawing however much air the injectors are consuming through the vent. Is this a viable option?

Thanks. Brad.

Guys,

EZ Return Fittings: New Sizes Now Available - Team CPP

Anybody ever....?

Thanks. Brad.

Looking at some of the items that you have made, it's obvious that you are a craftsman at what you do,

but as somebody that has worked on these engines for many years and also have owned numerous boats with twin 496 engines I just have to ask,

496, an engine that's been for the most part trouble free and proven, are you making things overly complicated and redesign things that do not need to be redesigned?

Cool watching you make one of items,keep up the good work.

BoatNT,

It’s a curse sometimes. :rolleyes:

No. I don’t think I’m overcomplicating things. I started the custom fuel rail because I was suspect that it was a contributor to the failure. In retrospect, I’m not totally convinced. The builder is adamant that the cylinder went lean, and I don’t disagree, but the injectors passed Smitty’s inspection with flying colors. My running theory is that a flake of paint got loose from the CoolFuel, found its way to the injector, but was too big to infiltrate, so when I disassembled the rail/injectors, it fell away and eluded discovery. We will never know. But the fuel rail was well underway, so I followed through with it. I now have a BoM, a process and a collection of fixtures I can make more with, that I intend to pursue as soon as we have the prototype that will be on my engine proven out. It also facilitate a flow-through design, which I and many others believe to be a better means of fuel delivery.

The exhaust risers were an attempt to ensure we don’t get reversion, and thought it should be water jacketed. It’s actually a very simple design.

I really haven’t done anything else that I and the builder didn’t think needed to be addressed. And let’s face it…. The 496, while a proven platform, is not the ideal platform for any kind of power adder setup. So we corrected all those issues with forged pistons and rods, and modifications of the intake to improve airflow and eliminate the PCV conflict with positive manifold pressure under boost. And, also, let’s face it…. The ProCharger, while the unit itself is perfectly viable as a power adder, the kit they provide leaves a lot to be desired, which many of the issues that need to be addressed with regard to the fuel delivery requirements under boost either band-aided or simply not addressed at all. We have corrected those ills.

I also wanted to declutter the engine. As much as it may not look like it, I am a minimalist, and I am striving for a cleaner look. So anything that didn’t need to be on the engine went elsewhere, mostly the transom.

Now it’s just a matter of ironing a couple wrinkles flat, hopefully with enough anticipation to get them out of the way before the engine is back in place of it’s going to be an issue with it in the boat.

Thanks. Brad.

Going back to the filter head will be fine and works. I believe the 700s are plumbed the same way .
I`d put a fuel cooler in that line to prevent hydrolock.. not sure what youre talking about injectors and air ?? What air?

Dan,

Both work and both have benefits and drawbacks. I’m currently set up to run back to the filter head, and I’m pretty resolved to keep it that way. I’m just weighing options while it’s still possible to do so.

It’s a brand new fuel tract. Right now, there’s nothing BUT air in it. And, when I close it all up, making all the connections, that air will be trapped. I’m just trying to expedite the process of getting it all out. I’d like to get as much out as I can before relying on the injectors to consume the rest.

It’s all good.

Thanks. Brad.

Not sure i’d worry about it, but you could purge it with a fuel psi tester that has a release. Put it’s clear line in a container of course.

No need to purge system. 43psi of fuel pressure running a return takes care of that. Also, once ejectors open air is released to cylinder. "self bleeding"

Can just bleed from the test port on the fuel rail. Could also use that port for your fuel rail pressure

The air is a non issue.
Don`t sweat it .
Agree with ROOKIE

Rookie,

48.5lbs, FWIW.... :rolleyes:

Holley HP, for reference, if it matters....

Do the injectors have an extended "open" moment at "key-on"? Or are we just relying on normal cycling duration to do the purging? I get that air undoubtedly escapes way faster than fuel, but it still has to happen while the injectors are open, and that's a LOT of air to get out of the lines and rails at first start-up, all of which is just being dumped back through the system over and over until it finds its way through an injector.

Thanks. Brad.

Buona Merda,

I don't currently have a Schrader valve, or provisions for one, on the rail. I've been running on the notion that having a FP gauge at the regulator would be sufficient. I can easily add an NPT bung to it, though. Maybe I should...?

Thanks. Brad.

You are way over complicating and over thinking this none issue.

Agreed. Just make sure your filter is full of fuel and send it.

That`s person #3 that agrees it`s not an issue yet you`re still going.
If you`re not going to believe the advice you get why bother asking the questions??.. dont be an askhole Brad

So just leave the hose off the fuel rail while you run the fuel pump .. then you only have this so terrible "air" only in the fuel rail.:rolleyes:
Holley will "fuel prime" on key start .. it will only do it once untill it sees rpm.

UnderPSI,

Probably. That's my way. But that's how I've gotten to be the toolmaker I am: asking questions. I'm not trying to find a way to an answer I want. I'm trying to understand how things work.

Thanks. Brad.

Ryan,

Planning to do just that.

Does this "fuel prime" just run the pump up to pressure or does it open the injectors for a bit beyond just normal cycling?

Thanks. Brad.

Like most efi’s….Just for a few seconds.
engine has no fuel psi sender.

You set the time in the ECU. I have 3 seconds. When I'm trouble shooting or draining the tanks I set to 99 seconds.

You should start learning this stuff ..download the Holley software .. you are going to have to do your own tuning .. Things like cold or hot starts can`t be tuned on the dyno and you only get one chance a day for a cold start ..took me a while to get that dialed in

Dan,

Oh, HELL no. The whole reason I ended up with this Holley HP ECM is because the previous owner wouldn't STOP fiddling with it. Or, more to the point, wouldn't stop allowing his buddy, who apparently didn't know what the farq he was doing, fiddle with it. The guy I got it from is an acquaintance of my builder. Apparently, the seller kept allowing the OTHER guy to fiddle with the tune, instead of doing what my builder was telling him to do, and he got frustrated with it and went back to carbs. I got the ECM, harness, 3B MAP and FP regulator for $1300, because he wouldn't stop fiddling with the tune, and could never get it to run right. I told my builder that, if anybody was going to be adjusting the tune, it was going to be him. This is not to say he isn't going to educate me on some aspects, such as the startup prime parameters, that I might be able make adjustments to. As I've stated, he already has a base tune that he thinks should be close; this isn't his first rodeo with an HP. And I'm sure there will be a couple three trips to the ramp with a laptop getting it dialed in. I suspect we are going to be doing a fair bit of boating together, at least for a while. I will have capacity for O2 sensors in both banks, so I will be able to at least monitor AFRs.

But knowing that, or at least it appears, the injectors do, in fact, let more than a typical cycle of fuel (or air) through at key-on, is precisely what I was asking.

Thanks. Brad.

https://cimg6.ibsrv.net/gimg/www.off...1698e5e7a.jpeg
Brad,

my current situation, I personally I like the way they look stock but you do you, by the way you should have a fuel schrader valve on your fuel rail. I owned numerous 496s throughout the years they all had them.

BoatNT,

That looks cool. I particularly like the Corvette flags badging. How did you paint them, being plastic and all?

Yes, the OEM fuel rail has a Schrader valve. I just figured that a FP gauge anywhere on the high pressure circuit would suffice. I can add one easily enough, and will do so before final assembly.

Thanks. Brad.

Hydrodipped, and I thought the corvette badging adds a like to the look,lol

when I built my '60 cadillac with the LS I used a corvette filter/regulator unit that is mounted at the tank so it returns in the first foot. from there it has 20 ft of fuel line that is dead headed at the fuel rail so no purge for the air other than the injectors. it only took a couple of cranks and it fired right up. air bleeds out of the injectors real fast so I wouldnt worry too much about it.