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GeneD
10-15-2000, 09:58 AM
Well, took ole 007 out for it's break in and low and behold, I had to paddle back.
Made the big mistake of taking it out for a happy hour run, and well, by the time I got out to the ramp, it was dark.
Freaking thing started right up, no pumping of the throttle, nothing, hit the switch and blam!
I had a shifting problem, that I narrowed down to my brand new drive cable. Took that thing out and put my old one back in and it shifts like a dream.
Pulled out into the beautiful Indian River, the harvest moon was just coming up over the eatern horizon.
Nailed the throttle and brought it up to 2500 RPM's. Trimmed out and cruised for about 2 minutes. The motor cut out.
Done.
Wouldn't start again. At first, I thought it was fuel, but no such luck.
I rapidly, in the dark, with no flashlight, traced the malfunction to lack of spark. Felt around, didn't find any wires loose or anything.
By now, I'm a mile across the river.
So...I break out the old paddle and start a paddlin'.
Got to cut down on the Marlboros, believe me.
Finally got close to shore only to realize I am about 50 yards south of the ramp, with rocks rapidly approaching. Stripped down to my Stafford's and jumped into the very cold water and walked that bitch over to the ramp. Shimmied my way onto the dock, only to find my butt in squid. Some jerk left their bait laying all over the dock!
Long story short, pulled the boat, and waited for the morning to check the problem.
Broken wire on the microswitch.
For those that do not know what a microswitch is, that is the electrical device that cuts power to the motor when you shift.
A soldering iron and some solder, and the damn thing runs like a champ now.
We're headed out right now to check it out.
Oh, and BTW, I found some literature last night that said there is no breakin period for Moly rings. Moly rings seat instantaniously. That is their big claim to fame. The chrome rings require a breakin period, but they are not recommended over the moly rings.
Whatever!
We'll take it easy for a little while, then we'll see.

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GeneD
007
Melbourne, Florida

Frank Civitano
10-15-2000, 08:46 PM
Hey Gene.
How is she running now. I know that rowing feeling! EECH! Thats why I carry a Boat Us Tow Me anywere in the US card. I let them come and get me. Hope she is running better.

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Frank Civitano

GEOO
10-15-2000, 08:55 PM
Boy Gene you're amazing. Your boat is never down for more then a couple of weeks!! Motor shot no problem, few weeks later up and running better then ever. Anxious to hear how she goes!!!! I hope I can run once more this season!?!?!!GEOO

Blewbyu
10-15-2000, 09:00 PM
Gene-I'm sure that many of us are nearly as delerious about hearing that hummer torch off as you were!After being on the beach for a long time with a mechanical,it's nearly orgasmic to hear the old pipes bark again.May the wind be at your back during the test phase(and the tide too)-and may nothing go "bang" and extrude itself from the block!
Best of Luck-Jeff

BigGrizzly
10-15-2000, 10:08 PM
Great job Gene, you forgot that old saying look before you seat. Hay Gene may you never see the tail pipes of a Sea Ray P. or a Baha again! I know how you felt when 007 started. I am enbarking on a similar project. I will let you guys know when I'm done. Best of luck and keep the deep vee down, the stripe up and your hair dry.

GeneD
10-16-2000, 11:08 AM
Gosh...she runs great!
But...no where near the power of the old motor. I am wondering if this roller cam is of nominal performance.
She gets right up, no problems.
Drove her around a while, perhaps maybe 1 hour or so, nailed the throttle, and got right up to 60 MPH on the speedo.
Idles like a dream. Starts up like she was never off.
One problem though, I don't feel that instantaneous thrust when nailing the throttle.
Who knows what the timing spec is for a 1995 Merc 350 cu in?
I think someone said 10 BDC? I'm running 8 BDC now, and I think it's not enough.
I've got to check total timing too, who knows what that spec is?
GEOO:
It's not like I have a job to go to everyday, you know what I mean Vern? I do my resumes in the morning and then go to the shop and do my motor thing. It's taken a lot of scamming to get my parts, and before my CC debacle, I only had a little bit of my motor money left. Hoping to hear from the bank today about all this stuff. I still owe the machine shop guy $262. Hope that's there at least.
I am seriously considering a camshaft change.
Big Griz, you got any specs on the newer roller cams? Figure I got standard 1.98 intakes, with the standard head chambers, with flat tops. The engine had dish pistons in it when I disassembled it, and they were replaced with standard Badger flat tops with the four valve reliefs.
I am also experiencing a rich carb condition that I can't explain. I'm thinking it may have something to do with the ignition timing, or the camshaft timing, but I can't be sure at this time. The reason I think I have a rich condition is the presence of a lot of soot on the transom, but that may have been from warm up. It takes a while to get the choke to open up. I'll check spark plugs to see if this is the case.
Also, I am not running a thermostat at this time and the engine temp is way down! I never ran a thermostat with the other engine, it always ran about 150-160 anyway. But this motor is really cold hearted! Maybe the water jackets are rust free? The other block, when rolled over to the dumpster, was making a lot of noise. You could hear the rust scales just pouring from top to bottom.
Anyone got any thoughts?

Oh, and one more thing, I am only getting 4200 top RPM. When the old motor did 4600-4800. Puzzling!

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GeneD
007
Melbourne, Florida

[This message has been edited by GeneD (edited 10-16-2000).]

RickSE
10-16-2000, 11:55 AM
Gene,
Your timing set-up depends on which distributor and controller your running. Thunderbolt IV's run 8deg. while Thunderbolt V's run 10deg. Thunderbolt V ignitions have a seperate control module for knock control and advanced timing control. T-V ignitions will optimize the ignition timing according to the load on the engine.

I have the specs for a 96 roller, probably used other years. I'll post them when I get home this evening.


[This message has been edited by RickS (edited 10-16-2000).]

RickR
10-16-2000, 01:17 PM
Gene
Before you set the timing make sure you ground the purple/white wire hanging off the advance (knock sensor) module if you have Thunderbolt V

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RICKR
mailto:riggerb@aol.comriggerb@aol.com</A>

rayjay
10-16-2000, 01:49 PM
Gene,

What compression are you running with the flat tops? Maybe you do not have enough compression for the cam? If you have low compression, what gas are you running? High octane may need more spark lead to get the same "bang" out of it. You may have to re-calibrate the ignition to use more initial advance and have less advance in the distributor. Low compression, small ignition lead, and high octane would go along with having the engine run cold, which is bad for the engine. rayjay

Forrest
10-16-2000, 03:27 PM
Yea GeneD, what cc heads are you using? If they are 76cc heads and you are using four-valve relief flat-top pistons you are probably looking at 8.8:1 to 9.2:1 depending on how much valve relief is cut into the pistons (assuming 350 cid, 0.030" over, 0.040" combined deck clearence and gasket thickness). If you put in a long duration cam, like rayjay said, you may not have enough compression. How well does it idle?

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Forrest

Greg Riach
10-16-2000, 05:16 PM
Gene

I'm running a hydraulic roller cam in my 350. I have noticed that timimg is very critical with this cam. When I bought the boat it would only rev 4600, after resetting the timimg (10 BDC 32 total) it will go at least 5800. I have the specs for GM Performance Parts cams if that is any use to you.

Greg

GeneD
10-16-2000, 06:11 PM
Okay, what's the deal?
This is the set-up.
I have the stock Thunderbolt IV ingition. With that of course, there is no adjustment possible beyond initial timing setting.
Heads are stock, I would imagine that they are the 76 cc versions.
Regular old flattops, with the four valve reliefs and the head gasket is the standard type Merc head gasket, more than likely the .045-.046 thickness.
So what are you saying the CR is?
Greg R brings up an important point there huh? Very interesting.
Forrest, the boat idles just great, no loping, just a loud barking exhaust. On the whole, the thing runs just great. I did notice when timing it, it seemed to want more advance. It liked advance. I pulled it back to 8 because of the spec. But this is the 1985 spec for a motor with a 1995 camshaft. Everything else is the same as the old motor. So cams being the only difference, would the timing be the trouble? I just don't feel as if the motor is developing full HP.
Tight clearances? It was basically a bolt together job. I checked clearances on everything and everything (rings and bearings) was right in the middle of the specs. I didn't check piston clearance, I left that up to the machinist. Standard bore pistons.
What degree thermostat do you suggest for this raw water cooled beast? If any.
Oh, and I was running a 50/50 combo of 93 and 89 octane. If that is any help to anyone. And don't get me wrong, this thing runs GREAT! (Beyond the soot on the transom.) It is just not performing up to expectations. And again, the only difference is the camshafts. EVERYTHING else is exactly the same as the old motor.
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GeneD
007
Melbourne, Florida


[This message has been edited by GeneD (edited 10-16-2000).]

BigGrizzly
10-16-2000, 08:09 PM
Gene, sounds like your timing is too retarded, 32- 35 is about where you want to be. As for the instaneous thrust, before the timing was way advanced in the old motor. You have at least two problems: 1 put in at least a 160 degree (if you run a lot of salt water make sure ther exhaust water is less than 160-salt cristalation) 2. get full advance up to 35 degrees. Yes cams affect timing, but only about 5 degrees in either direction . don't use high octane unless you have to. high octane burns slower and will carbon up the exhaust valves and soot up your stern. You could be jetted too fat. The new cam is the controlling factor. you need to build everything around it. Here is why I think it is fat, starts easy, idles throaty, pulls smoothly, down on top rpms and not laboring. Retarded timing also causes a rich condition. What ever you do only make ONE change at a time. check the plugs for a reading.
Your not going to like this but I think you need a smaller carb--600 cfm to get the velosity up. at 5000 rpms the 350 doesn't draw enough air for a 750cfm.

[This message has been edited by BigGrizzly (edited 10-16-2000).]

RickSE
10-16-2000, 09:17 PM
Here are the specs for a 96-97 350-Mag roller cam, from Merc. manual.

Lift:
Exhaust: .300 in.
Intake: 287 in.

Duration @ .050 Lift:
Exhaust: .294 in.
Intake: .307

GeneD
10-17-2000, 07:39 AM
The cam specs look to be interesting.
I didn't think you could use more than a 300 degree duration on a marine motor. But that is just what Mercruiser did!
The lift isn't all that much huh? .450 with 1.5's.
I doubt seriously that I have this cam. I have the purchase order for the motor that came with this cam, I'll call them up and see what the story is.
I'll try to re-do the timing. I'm thinking that the timing is not correct for this cam. As far as the carb being jetted too rich, I'm a bit skeptical about that, if anything, I beleive it's just not firing right. Here's another thing too, I've been thinking about. I'm using an Accel coil. Bad news with a Merc. I noticed that I had a rather yellow spark the other day when I had the "no spark" problem. I didn't give it much creedence at the time, since I hadn't had the boat out for more than a couple of minutes. Now, I'm going to hold it as a factor. I'll be down at the shop today checking on all this stuff. I want to check that X dimension too. I hope I got those instructions right.
Who knows at what speed the total timing maxes out?
I would imagine that my book will tell me all this, but it's not at home, so I can not consult it.

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GeneD
007
Melbourne, Florida

Jamesbon
10-17-2000, 08:00 AM
I know nothing about the Thunderbolt ignition, but I'd take a good look at timing. I'm running about 10-11 degrees on the bottom and 33-34 on the top (fully advanced @ +\- 4000K rpm). As you know, timing can make all the difference in the world. A serious milling of the 76 cc heads or a set of 64 cc's might really wake her up. http://www.donzi.net/ubb/eek.gif

Oh yeah, what carb.? I had good luck with the Holley 600 or a Quadrajet on my 350 c.i.'s. The Holley produced similar soot on the transom, even after several jetting changes, and the plugs were always black. I have the Quadrajet on the 388 now, and like it so far.....I like those d*mn Q-Jets!

[This message has been edited by Jamesbon (edited 10-17-2000).]

GeneD
10-17-2000, 08:21 AM
We got the old, stock, untouched, Quadrajet on this motor. The one that came originally on my 1985 260 Mercruiser. I haven't had a single day of trouble with it, and since it is performing adequately, we'll leave it alone.
Since the cold snap here has not gone away, I think my choke could use some adjustment. It really loads up during warm-up.
Got to dial in this bad boy. Just give me a little time boys!
As far as milling the heads goes...well, we'll just leave that alone for now. I am not willing to rip this motor apart just yet. It runs too good.
Let's look forward to the 400 sitting in the shop right now. I was reading the other day that Chevy makes a .016 thk SST head gasket. But I don't think it mentioned the 400's 4.125 bore. Also, the book said that the 400's shorter rods are not recommended for high RPM use. This means using 350 rods with new pistons. Who knows about this? I would rather use the 400 rods and just buy new flattop pistons, or perhaps blow the envelope and get some pop-ups? I will be using 2.02's with that combo (when they fall into my lap), and perhaps my racing roller cam. Though my 350 cam is perfect, and that might be the ticket too.

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GeneD
007
Melbourne, Florida

[This message has been edited by GeneD (edited 10-17-2000).]

Forrest
10-17-2000, 09:32 AM
If you decide to build your 400 block, use 5.7" rods and matching pistons. Also, though a 160-degree thermostat will be better for engine efficiency, I would use a 142-degree thermostat for raw water cooling in Florida since sea-water saline content gets higher as you go further south.

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Forrest

GeneD
10-17-2000, 09:40 AM
I think I have a 160 in the shop, I'll check today. I'm damn sure I don't have a 142. More money!
Why use the 350 rods in the 400? Is there some technical issue I'm missing? The fact is that I would have to grind away part of the rod bolt to get it to clear the camshaft, and while that seems to be the norm, it bothers me a bit. I guess doing that wouldn't be the end of the world since I am going to have to replace the pistons anyway. I have a bunch of 350 rods laying around too.
Who was it that said they had a set of 400 pistons to sell me? And were they the ones used with the 350 rods?
Forrest, do you know about this .016 SST gasket?

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GeneD
007
Melbourne, Florida

[This message has been edited by GeneD (edited 10-17-2000).]

woodsy32
10-17-2000, 09:44 AM
I would be careful using a 400 block. I seem to remeber for some reason they are prone to overheating. I think the trick setup was a 400 crank in 350 block. I guess it gives you a 383 cube motor. GM actually sells this setup themselves so there must be something to it. I don't think there is any shortage of 350 4 bolt main blocks. Should be able to pick one up cheap! Just my $.02

RickSE
10-17-2000, 10:09 AM
Gene, did I send you the write-up on the 400 build up last year? Maybe I'll post it in a new thread.

400 rods work fine as long as their prepped good (magnaflux, grind the beams & stress relieve, then shotpeen), also make sure they have “GOOD” (ARP’s) rod bolts. The rod bolt is the weak point of the 400 rod.

The advantage of the 400 rod is that torque numbers will be a lot higher for a motor with 400 rods than one with 350 rods. The original 400 was designed to be a low RPM torque monster. If you want a screamer over 5000 RPM's use 350 rods. If you want a 5000 RPM'ish torque motor than use the 400 rods. I used 350 rods in my 400 drag motor only because I needed the RPM's, shifting at 6700 RPM's, but for a boat motor I would seriously consider using 400 rods.

Also, (I don't wan't to piss anybody off here) but don't ruin a 400 crank by putting it in a 350 block. Take full advantage of the extra cubic inches in the 400 block. Just make sure the water passeges are clean. I drove my 11.5:1, 450 HP, 400SBC in Phoenix three summers in a row and it never overheated.

[This message has been edited by RickS (edited 10-17-2000).]

PaulO
10-17-2000, 11:14 AM
Supposedly, the 400 rod has 3 disadvantages:
1. More force on the side of the cylinder wall possibly resulting in increased out-of-round.
2. Forces piston pin to be located higher in the piston which leaves less room for heat transfer and ring lands.
3. Price and availability.

Have not heard of a builder who wants to use 400 rods.

PaulO

Forrest
10-17-2000, 03:04 PM
Besides the rod-angle ratio problem that PaulO mention in point #1, longer rods increase piston dwell at TDC which allows more time for combustion to create work energy against the piston. Not only will torque be increased with a longer piston dwell at TDC, but fuel octane requirements for a given compression ratio will also be decreased. In other words, you may even be able to get away with using regular 87-octane fuel on a 10.5:1 motor if the rods are long enough.

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Forrest

BigGrizzly
10-17-2000, 07:01 PM
GeneD, Use the long rods from the 350. The short rods go accross top ded center at a accelerated speer causing damage that PaulO described. Short rod have greater acceleration at low end but loose at top end power. Team honda used short rods on their super bikes, but had many more engine rod failures- spun bearings broken rods. I used longer rods and we finished seventh in the nation, no rod failures. Hay Rayjay remember? I'll call you tomorow, I may be up your way this weekend Moms 90th birth day.
RickS some thing is wrong with thoes cam specs, way too much duration at 0.050 and the lift is too low. If lift was measured at the lifter not the valve, then lift would be 0.450 IN and 0.430 on the EX. The duration even measured at 0.50 the spec would be around IN 233 and EX 245. please recheck spec.

[This message has been edited by BigGrizzly (edited 10-18-2000).]

GeneD
10-18-2000, 08:40 AM
Well guys, thanks for all the info. It's a lot of food for thought.
As for the timing on this engine. I bumped up the timing to 10 BDC, and it had NO effect whatsoever.
I checked the compression, a full 165 lbs. No problem there.
I checked the spark plugs, totally dry. Really nice looking porcelins, ect.
BUT...a really nice yellow spark. Actually, very pretty shade. I think this is where the problem is. I blew a coil recently, (over the summer) and was in a jam and bought an Accel coil. You know the one, the $25 unit that is also a very racy shade of yellow?
While the engine was running and I was checking timing, I heard snapping by the distributor, and narrowed it down to the coil. Last night, in the dark, it looked like St. Elmo's Fire in there! A blue plasma covered most of my wires, and the coil was just aglow. The hotter the coil got (the longer the motor ran) the less power I was getting. Soon, during an extended run (10 minutes) at 4000 RPM, the engine slowly began to lose RPM speed.
I am going to concentrate things in this area first.
Oh, and the rich condition I was experiencing? Turned out to be my choke! The damn thing was closed! Too cold here now. I had to re-adjust, and now it seems fine.
Got to dial in...

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GeneD
007
Melbourne, Florida

rayjay
10-18-2000, 08:51 AM
I think I'm waking up, stayed up to make sure 'da Bron-ex Bom(b)ah's made it into the series.

Big G, let me know. Would be nice to see you after all these years.

GeneD, use the LONGEST rods you can find. There are 400 pistons readily available for 5.7" rods, and there are more and more pistons for 6" rods. 6" rods are very common now, and easily obtainable from Summit or whoever. We used to use Olds 6" rods with a little rework, but you do not have to do that anymore. Trick Flow has a mid-weight 6" rod which only costs a few more beans than Chevy "pink" 5.7's and are a whole lot nicer and lighter. Longer rods will help the engine tolerate a higher compression, which is good for power, as well as help the pistons and rings have a longer life at higher rpm's. Just make sure you get your 400 crank done properly. If you are going to go to a forged crank, you can easily get one with longer stroke for an even bigger torque monster.

Can't wait to see what engine BigG cooks up as he alludes to in another post. But it will probably remind me of an old adage, "don't bring a knife to a gun fight" (lol). rayjay