Paxtonspeed

07-306-8 - Xtreme Energy?
230/244 112 LSA 108 ICL
Just ordered this cam....LET ER RIP TATTER CHIP!
Has a little more exhaust duration than the standard 230/236 XE cam and about all the other 230 ish cams out there.
This should help with the crappy exhaust.
We will see what happens!

Paxtonspeed

Well I busted my hump and got the cam swapped out.....that was terrible to do in the boat. Would have probably been easier to just pull the motor and do it on the stand. I didn't realize my fat ass could still fit in such tight places.....LOL. I found an oil leak that I was able to fix while I had it apart as well. The intake gaskets I installed are 100000% better. If you have a vortec style engine these are the gaskets you want. They are metal, with embossed rubber around the ports.

https://www.summitracing.com/parts/fel-ms98000t

I had to cut a hole, with a hole saw in the back of my rear seat to make a cam access hole...LOL.








Got her fired up in the driveway, set the initial timing, had to re-adjust the throttle blades to get the IAC counts where they needed to be, and I bumped the idle up from 600 to 700 RPM. I lost a little vacuum at idle, which made it run in a different MAP cell making it rich. So just a little bit of base tuning in the driveway and she is idling great! As far as I can tell there is no reversion. My wideband is still working great. I pulled it out and there is no water on it. I also started the boat, with the sensor out, no water. I let it idle for a good 20 minutes....nothing. Another plus to the swap.....my valve train noise is gone. I had a tick before that I just contributed to the aggressive lobes on the XE cam. Well I put in a more aggressive XE cam and the motor is as quiet as a church mouse. I know there are different variations of stock Merc exhaust setups. Some have the risers right on the manifolds and some have spacers like mine. I am wondering if having the spacers is what is giving me the advantage of not reverting any water, I don't know for sure. I do not want someone to read this and think they can just slap a cam like this in their boat and not have any issues. I also think the EFI helps a lot. You can essentially smooth the cam out with the EFI, by running more timing at idle. The ECM also has an idle overspeed / underspeed feature the advances the timing for underspeed and retards for overspeed. This happens very fast and can be seen with a timing light while the engine is idling, after the base timing has been set.

In the next few days, I am going to take the silencers back out. It just sounds better that way, and I have not had it on the lake without them in the boat.
Here is a video with the new cam.

Paxtonspeed

A couple more videos, the cover over the ECM / relay center, whatever its called, squeaks a little.

Paxtonspeed

Hey guys! I caught a summer cold! My kids have only been in school for three weeks, and have managed to get me sick, so I have been moving slow. Anyway, I did get out to the garage on Sat. and took the silencers out of the boat. They bolt in, but my dumb butt tack welded the other ends to keep them from rattling, so I had to grind the tack welds out. I pulled the plugs and they look darker than before, and non of them are wet with oil or water. I am pretty sure I fixed the intake leak and I have no reversion. I am hoping to get her out at least one day this weekend to see how she runs. Here is my last idle video in the driveway...LOL. The next videos will be on the water. Hopefully I will be giving an update saying the spark knock is gone as well. You can see the water seems to flow out the exhaust a lot easier and with more force, without the silencers restricting it.

PA.WOODCHUCK

Any update on this project?

Paxtonspeed

Yes I took it out a couple weekends ago.

The boat ran rough. I have been dealing with my tach fluctuating, suspected a bad tach so I unplugged it, no change.
I am 99% sure the shift interrupt switch is bad. I have read several forum posts of guys replacing everything in the ignition and still dealing with a fluttering tach and the boat still cutting out.

Apparently, Mercruiser changed the switch design and the way the switch interrupted the shift. The older carb setup used a microswitch that grounded the coil. The EFI engines have the 12 volts going to the ignition running through the switch, which is a different style switch, compared to the old carb style.

I took the switch off, cut the leads, and hooked it to a DMM to check the resistance of the switch. Obviously I should have seen a dead short until I pushed the switch, which should make it open. The meter fluctuated badly, and the resistance was all over the place. I never could get a a dead short out of it.

I have the new switch, just have not installed it yet. Its also been raining for four days, and is starting to get cold. I am going to try and get the boat out again before it goes into storage.

With all that being said, even with the boat cutting out, it obviously has more power, and seems more responsive. The boat starts and idles great, I did have to do some crank fuel, idle, and overall fuel tuning. Due to the cam having less vacuum.

Paxtonspeed

Well guys, its cold. Put her in storage yesterday. I did install the new switch. I ran it in the driveway and my tach fluctuation is gone. It also seems to rev better.
I am pretty sure its fixed. Anyway, I will update this thread in the spring!

Paxtonspeed

Brought her home today! Hope to get you guys some good info! Going to change the prop to a 21 pitch 14.5 inch Solas HR Titan SS prop. I am going to get some WOT run video as well. I am pretty sure the shift interrupt switch was causing a lot of my headache last year. We shall see!

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Paxtonspeed

All right guys. Here she is on the water. The shift switch fixed the tach problem and the boat runs way better. I was still getting just a little tickle of the knock sensor at WOT, with 32 degrees of timing, AFR was 12.5. I took one degree out and richend it up a little, AFR 12.2. It got better, but still get just a spot of knock every once and a while.

I changed the prop from a 17 pitch by 13 3/4" to a 21 pitch by 14 1/2". My RPM's have dropped. Before it would turn 5000 RPM or more, now its about 4500 max. It will peg the speedometer (60 mph) with me in it by myself. In this video there are 4 people in the boat and we had a head wind. I dropped every body off and went out by myself and was able to get more out of it. It also seems like I can trim it up more than I could with the old prop, which I did not do in this video. You can see my voltage gauge blip when I trim it up. Also, do not pay any atention to the wide band read out, its not right. I still have my hand held installed.

Anyway, what do you guys think? Did I make a good choice on the prop? The boat seems to cruise real nice at 3000 RPM. I have thought about putting a 4 barrel TBI on it to get rid of the 2 barrel 95 KPA seems to be about all I can get out of it, which may indicate a restriction, if it won't hit 100 KPA at WOT.

articfriends

Your never going to see 100 map unless you have the best air ever. I've run scannerpro on 40 or 50 engines in boats and on dyno, 98.5 is pretty good with tb mods, good or no fa, seen 94, 95 even less with over taxed tbs or restrictive fas etc fwiw, Smitty