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GeneD
11-11-2000, 10:35 AM
All you know the trials and tribulations of 007, mainly the engine problems I have encountered as of late. I for one, do not hold anything back from you guys. I tell all. And not because I’m bragging, who really wants to brag about their boat breaking down? But because I truly believe that everyone can benefit from my mistakes or bad experiences.
I have done a mess of research into this motor thing, and now the real story has unfolded. In my research, I found some disturbing info for me personally, since I owe someone an apology. More on that later.
Let us re-cap the past. I suffered two "tuliped" valves in the past year. My Sea Ray buds were saying,
"Yeah, that’s caused by…, Gee I remember in Merc school they said it was…"
No one could remember. The final thought was, it caused by bad fuel.
I scoffed at that.
I also found two plugs (in the blown out piston cylinders) that had no electrodes. I thought it was a manufacturing defect and brought them back for replacement. At $5 ea for plugs, I wasn’t so willing to eat the cost.
Then two weeks later, I blew the engine. 3 bad pistons, 3 spun bearings, and a cracked block. The area around the cracks, which were cracked across the main bearing webs, looked to be super heated. Nothing unusual with that considering the bearing spinning against the block right? But the burned out pistons bothered me.
On to a new engine. The new motor is perfect. Everything was to spec, and meticulously assembled. But…no power. At least no power like the other engine. I could feel that something was wrong. Also, unreported, I think, was my 4 bbl bog. Not always there, but often it would bog on full throttle application. Timing? Advanced the timing 2 degrees, and got no gains at all. No improvement.
Checked the plugs, very dry. Nice tan color.
Then I started doing some research on Thunderbolt ignition timing. That is when I found the Mercruiser Service Bulletins. While going through the bulletins, I found one that talked about secondary metering rods in the Quadrajet and how you needed to change them out for high altitude operation.
The chart went through a number of engines. I looked at the metering rod code for the stock sea level 5.7 Alpha, and it calls for a CL rod. Then you go down to the 350 Magnum, and it calls for a CH rod.
Hmmm, I thought, I’m going to change out the secondary metering rods on my Q-Jet to the rods they call for in the Magnum, and see if that makes any difference. Perhaps I can pick up my lost RPM’s from there considering I now have a different cam, and I do not have the Alpha engine anymore, but still have the original carburetor.
So I go to the shop and remove the rods. What did I find in there but DW rods! The DW rods are the secondary metering rods that should be used on the Alpha engine at 9000 ft and above! But what does that mean? I did some more research and found out a bunch of things about the Q-Jet. For one, they make only two castings. A 750 CFM version, and a 800 CFM version. Both of which are jetted for the various CID’s engines on which these carbs are used.
I had a rather heated discussion about this with someone recently, and I apologize. My info was garnered from my old engine builder on Long Island, a man I trust explicitly. I think what he was getting at was that the formula used to calculate jet sizes, called for a 450 CFM jetting on most 350 Chevys. I was wrong about the CFM castings, and I’m truly sorry that I was a stubborn jerk about it.
On to the rod change. I found another chart that talked about the diameters of the rods and what the codes meant. Thank Don for the Internet, (he invented it didn’t he?). On that chart it said that the codes vary in diameter according the alphabet, kinda. For instance; letter code "CC" is .030 diameter. Letter code "AX" is .040 diameter, and letter code "DA" is .044 diameter. I had DW’s in there. The same code for the 9000 ft and above altitude. A much bigger diameter than the "C_" codes it calls for at sea level. The bigger diameter of the rod, the leaner the fuel mixture, conversely, the smaller the diameter, the more fuel you pump in.
So in the end, I was running a very lean condition. Causing extreme heat and the resulting "tuliped" valves, and the eventual breakdown of the entire engine.
So, the other day, I went around to all the junk engines we have laying around and ripped off all the secondary metering rods I could find. I found the ones I was looking for, and found out some other interesting things. The late model motors have bigger diameter metering rods. I think this is for producing a lean condition for emission purposes.
I also found the air valve diaphragm on my Q-Jet unit bad. Couldn’t hold vacuum in it. Didn’t find one of those, but we will find one soon. I believe this is the cause of the secondary "bog".
In the end, we will put the correct rods in there and see what, if any, difference it makes. How did this happen with an engine bought in Florida? This is what happens when you buy a motor that came from the Prototype Design and Development Division of Sea Ray. Apparently, they had a high altitude motor on consignment for some project that never got off the ground, and sat on the crate forever until they decided to sell it at an employee auction.
Caveat Emptor!
I'm taking the boat out for a ride right now. Hopefully it will make some kind of difference. I will report later on this.



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GeneD
007
Melbourne, Florida

GEOO
11-11-2000, 11:36 AM
Gene, I feel for you. Fixing the problems is easy. Locating the problem is difficult. Good luck. GEOO

GeneD
11-13-2000, 08:59 AM
Well GEO, the search continues!
The metering rod change out DID produce "some" improvement, but not what I expected.
I raced a 25 ft. cig type boat with a worked 454 and 'barely' beat him. They kept giving me the "let's go" look, but I could barely beat him out, maybe 1 or 2 MPH faster than him. They were very surprised, considering last time I beat him, I blew him away.
I HAS to be the cam and heads. Either I will be selling this fantastically running eninge, or I will change out the new heads and cam for the old stuff.
Quite a learning experience. I was totally convinced that the roller cam set-up would be even more awesom than the old set-up, and I have been severely disappointed.
Oh, and I had three people in the boat, half tank of fuel. So maybe there was a performance difference I didn't notice with the extra person on board. I still have my bog, but it doesn't affect WOT performance. And I haven't checked my plugs yet, so I don't know how rich or lean the rod change out affected that. But it did run good, everyone admitted that much. Just not the animal it used to be.

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GeneD
007
Melbourne, Florida

GEOO
11-13-2000, 10:27 AM
Gene, I have a new book on High Performance Small Block Marine Engine's (Chevy). It gives stock cams and recommends engine combinations, (cams, intakes, etc..). If you want to check it out, E me your address. GEOO

GeneD
11-15-2000, 07:56 AM
Well, jury is still out on this one guys.
Does anyone know if the 1985 harmonic balancer has the timing mark in a different location than the 1996? (I just found out that this is a 1996 motor, not a 1995)
Also, it seems that the heads have a casting number on it that says XXXXXX217. I didn't write down the rest of the numbers, usually you only need the last three numbers right?
I did a casting number search and it says:
14096217...55-86...350...Crate motor, 285hp/300hp, 64cc chambers, 72' or 90' center intake manifold bolt angles.
So now I don't know what to think about the heads. I will take another look at the numbers again to see if they match up exactly. If this is true, it might explain the high static cranking pressure?
I have MadPoodle looking into the exact cam they sent me, hopefully he is on the case.
Here is another tidbit...my old heads were 624 castings. According to the V-8 Interchange Manual, they are 74 cc chambers. Making this whole thing very confusing.


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GeneD
007
Melbourne, Florida

[This message has been edited by GeneD (edited 11-15-2000).]

Jamesbon
11-15-2000, 09:25 AM
Not sure about the last three digit thing, I would get the full casting number from the top of the head as viewed with the valve cover off. ??

GeneD
11-15-2000, 09:39 AM
Nate,
That is exactly what I did, just didn't write it down. Just looked at the last three numbers and buttoned it back up.
Normally, that is all you need.
I have a bunch of heads, I lined them all up and checked each one out.
(BTW, I am missing a 462 head for my 400 if anyone if FLA has a bare casting laying around they don't know what to do with)
I am running a 041 set of heads in the Corvette and love them. Wish I could get a set for the Donzi.
Anyway...we'll get that complete number and zero in on the problem. I just got an email from the MP, and he has agreed to check the cam out for me. The place we got the cam is in Hialeah and that is HIS stomping grounds, so he'll be the man that will straighten this all out.

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GeneD
007, a teeny bit faster, but not much
Melbourne, Florida

[This message has been edited by GeneD (edited 11-15-2000).]

DS88
11-19-2000, 06:43 PM
GEOO,

Could you post the ISBN number of your new book on Hi-Po small block marine engines, I'd like to pick up a copy.

Thanks,
Dave

GEOO
11-20-2000, 01:40 PM
HEY Gene, Can you post the Book info for Dave? GEOO

GeneD
11-21-2000, 07:56 AM
I've been sick for the past week or so.
On my back with some flu like thing that the child brought home from school.
I haven't been to the shop lately. But I will be there tomorrow to pick up my mail. Hopefully I'll feel better by then. I plan on picking up the boat so that I'll be all set for my Thanksgiving morning ride.
Hang in there.

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GeneD
007
Melbourne, Florida

RickR
11-22-2000, 08:29 AM
Gene
Apology accepted.

Metering rods are available through Summitt Racing.

Sometimes you can adjust the "Qudra Bog" out by bending the rod on the vacuum actuator.

Get Well Soon!



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

Forrest
11-22-2000, 08:33 AM
RickR, are you still down in Panacea?

Its got to be cold out on the Gulf over the last few days.

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Forrest

GeneD
11-28-2000, 10:14 AM
GEOO, and all,
Sickness gone, feeling a hundred times better. Flu sucks, I hate it. And those with children know that "they" are the ones that bring it home.
Anyway, had a great time checking out the book GEOO sent me, and all I can say is "WOW"!!!!
Everyone should have this book. Every single question I have had in the past three months is answered there.
I will form another post sometime today or tomorrow to list the number you all can order it with, and to give my evaulation on it's contents.
BTW guys, I think I have found the problem with the performance end of my motor, and I think it has to do with piston pin height.
If my theory is correct, the piston is .025 down in the cylinder, and with a .038 gasket this puts the quench dimension way out.
We'll see.
Later...

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GeneD
007
Melbourne, Florida

PaulO
11-28-2000, 12:48 PM
Gene,
You are most likely correct about the quench being wrong since it almost always is. .024 below the deck is the standard SBC spec. Only when gaskets got thicker (composites) did it matter because the old shim style gaskets were only about .014 compressed. Unfortunately though, the difference in performance is rather small. I don't think it would account for what you are experiencing.
PaulO

GEOO
11-28-2000, 03:23 PM
Gene, Glad to hear you're feeling better. I thought you would find that book interesting. GEOO