Not Always What It Seems

[GeneD]

Tech Time on the Donzi Registry!
As you all may know, the motor in 007 took an untimely demise.
Started out with a tuliped valve, no compression in #2 cylinder. After that was repaired, a knocking sound was noticed. But with the noise these boats make, it was hard to diagnose.
When warming up the motor during the last day of operation for the ill fated '86 260, heavy smoke was observed coming out of the valve covers. My immediate reaction was that a piston had let loose.
This was not to be the case.
After tear down, two spun bearings on #'s 3 & 4 cylinders was discovered. Also, spun bearings on #'s 2 & 3 crankshaft mains.
Total teardown revealed 3 bad pistons. But nothing that would have caused the tremendous amount of oil smoke coming out of the motor.
Further inspection showed heat discoloration around the main bearings.
THIS is what I believe caused the tremendous smoke bomb in my engine compartment. The area around the mains got extrememly hot and the oil was burning on the metal.
Check out the main caps.

http://albums.photopoint.com/j/View?u=1173240&a=8637555&p=28504026

The block was found to be cracked too at #2 main.
Block is now in trash can.
New motor is choice. Replaced all soft parts and installed new pistons. Funny, the old pistons were smog type! Low compression. We now have flat tops. Check out the new cylinder in #5.

http://albums.photopoint.com/j/View?u=1173240&a=8637561&p=28504144

Learning alot about the new motors, and I am documenting the differences with my new digital camera. Hopefully we can get it into the Tech Section soon. This will really be helpful to any motorhead that is planning on doing a swap.
I've had to completely change over.
New flywheel, oil pan, valve covers, and intake. The cam timing gear is also different, but only for the roller cam. Most everyting else is interchangeable.
I was pretty surprised with what happened to my reliable old 260, but all in all, it served me well. Especially considering that fact that just prior to the smoke bomb, we had been doing 60 MPH the week before!
Motor troubles are not always what they seem, this is living proof.
Oh, and sorry guys, but no...I will not be putting the dual quad on this motor. Just a gag. I'm selling the intake on ebay and I thought it made an interesting photo.

------------------
GeneD
007
Melbourne, Florida


[This message has been edited by GeneD (edited 09-16-2000).]

[BERTRAM BOY]

Gene,
What kind of oil pump/ oiling system was in this... shall we say.... paper weight?
BERTRAM BOY

[Gearhead99]

Gene,

I don't feel that you lost the motor over an oil problem. I still believe it was detonation. The detonation will beat the piston so hard and get it very hot. The heat is transfered down the rod to the crank. The detonation causes the bearings to take the beating, with the high heat, at the six and twelve o'clock position. This causes the bearings to thin out and pulls the locater tabs away from their respective grooves and the bearing spins. The high heat is from the detonation. Also, the pounding at the throws extremes.

I have seen this too many times on marine engines, mostly mine!!, from too much advance. Also, some short track engines I use to build for a guy. When he got cheap and didn't want to run the "race" gas, he thought it was too expensive, and ran 93. Needless to say it cost him a motor.

[GeneD]

Dave,
Could very well be.
I told you and everyone else that I did purposely set the timing way advanced prior to this catastrophic breakdown.
I am reserving judgement.
Secretly, I am thinking SABOTAGE!
And I'm not joking.
Funny how I came back from Deerfield Beach and my boat was screwed up. If you all remember, I was in Deerfield Beach for two days while my boat made it back to Melbourne on time.
Weird.
Doesn't matter now. We got the new motor and it's gonna be great!
Can't wait for break-in.
Forrest, (or Dave, or Big Grizzly )for me and all concerned...
What is the normal break-in period for a single moly ring set?

------------------
GeneD
007
Melbourne, Florida

[This message has been edited by GeneD (edited 09-16-2000).]

[Gearhead99]

Gene,

Happy B-Day to you.

Break-in............I would run it 25 hours or so. Don't let it idle to long. And after running it, let it cool down at 1000 rpm or so to stabilize the tempertures. Then change the oil and let it rip.
Oh, yeah, recheck timing and total advance.

Sabotage??????????????? Maybe true. I wasn't there, but you said you ran the snot out of it and with the timing up high, you're going to detonate. Just a matter of fact. If someone else hurt it on you, they would have to bump the initial timing up and then you would probably have trouble starting it [holding back]. Some crap in the oil, wouldn't cause the damage you discribe. Keep the timing in reason, or buy another motor to replace this one when it lunches, I'm speaking from experience. Donzi I had in PA used 3 that's right count them THREE engines [351W Holman-Moody's] in 4 months. Hard running and too much spark. On second thought I did lose one engine when a motor mount broke after landing off a LARGE wake and tore the oil cooler lines off cooler and lost motor. What a mess the bilge was, 10 guarts of oil in bilge. Yuck!

[BigGrizzly]

Gene are you running thin rings or std. moly rings break in quickly, chrome takes along time. hope ypur engine builder honed the cylinder with a 320 or finer. cuts break in time down and makes for better sealing. In really whish you had a closed cooling system, you could run it hotter. 25 hours I think is a little long. If your going to run the stuff out of it all day --like driving from Miami to Nassau then-, then 10 hours maybe. In the real world four hours. Remember you have Moly rings three piece oil rings (the real reason for long breakin one piece oil rings) roller cam and a seasoned block as for the bearings they don't contact the journals, there is a film of oil between them if not, you have scored bearings . Oil is the next thing. All oils today are so good that breakin is all but useless. I was involved in oil tests for Honda for six months. Use a 30w change it after every use. Use same type during breakin ( never use 10w40 I don't care who makes it ,will explain when I have more time or in person.)period. Fill the oil filter with oil prime the block with the oil pump drive, not the starter motor, then start it up. Don't let it idle for the first 15 or 20 minutes, keep it about 2000 to 2700rpms. Recheck every thing then go out and do the rest of the breakin.
I still believe the problem was detonation. I have seen rods and cranks explode because of this. You advanced another 15 deg, this would put most systems at almost 50deg btc. OUCH.
People here may not agree with my breakin in procedures. My road race bike gets its engine breakin in 20 minutes and doesn't smoke. It also has a babbit bearing crank like your boat, but twists 11500rpms.
Don't worry if it was sabotage, they will get theirs, it always works out. Ehample- look what you have now!!! Happy B-day and best of luck with the new engine. Hope to meet you in person some day.



[This message has been edited by BigGrizzly (edited 09-17-2000).]

[Jamesbon]

Gene,
What were the differences in your timing gears? I have a roller set up that uses the old style cam gear with the addition of a cam button/or thrust button.

Just curious,
Nathan

[GeneD]

First of all, we/me are/am talking about the factory roller cam going into a 1987 and up new style block.
The factory roller cam has a shoulder on it that fits into a counterbore in the timing gear. Easily seen in this photo.

http://albums.photopoint.com/j/View?u=1173240&a=8637561&p=28084492

Before the gear is installed on the cam, a keeper plate must be installed using two tapped holes on either side of the block. I don't have any photos of the plate installed, screwed up on that, but here is a photo of the boss and the tapped holes.

http://albums.photopoint.com/j/View?u=1173240&a=8637561&p=28121808

Now you are talking about using a standard aftermarket roller cam in a new style block? I think it can be done successfully.
The new lifter bores are pretty high and would lend themselves to standard type roller lifters pretty good. I never did try my old roller cam in there, so I don't know.
HOWEVER!
I just picked up a 305 new style Merc that I used the sheet metal off of to put on the new 007 Donzi engine, so we'll take a good look at that too.
Thing is, using the new factory roller cam, the teflon button is no longer necessary. This keeper plate keeps that baby in there real nice. But the keeper plate will not work with an old style cam.
But...the old style cams will fit into a new block, so will the old style lifters.
Did this confuse you more or make things clearer?



------------------
GeneD
007
Melbourne, Florida

[Jamesbon]

That clears it up. I understand the differences b/w the old style and new style factory roller blocks now.

I'm wondering about the clearance in my set up. I have the old style Chevy block, and a retro roller cam kit. It uses the vertical bar to attach each pair of lifters, and a button that rides against the timing cover to keep the cam from walking. The machinist said there was proper clearance, but by looking at the timing cover and listening to the different sounds it makes when I tap on it, it sure seems like that timing cover is tight as b*lls against the button, thus putting extra pressure on the top cam gear and block face. I guess we'll see when I fire up this beast.

[GeneD]

It sounds right.
Now...about the roller cam, what have we learned lately about reversion? Do you have that solved?
I need to know. I would sure as heck love to put my old roller cam in my 400...someday!

------------------
GeneD
007
Melbourne, Florida

[BigGrizzly]

Gene read my past posts. The one in the reversion post. The only time you get water reversion is at idle or backing up, caused with short primary pipes. You see I said water reversion, exhaust reversion happens in some race cars at idle with really big cams. If you match your specs with my cam or Geo's I'll bet our real valve action is greater than the your roller and we don't have reverson. Read it then the one to Chris. If you have any doubts, get me your phone number and Ill call you and explain it to you in detail. Remember the last thing I want is to have you blow a motor, the next thing to that is, I don't want is some non-com in a stupid Baha to out run 007(this is a personal thing, love your boat)!!

[GeneD]

BG,
Let's not get hasty here!
This is just info for the future.
My 5.7L factory roller cam motor is going in soon. (hopefully this weekend)
The reason I ask about reversion on the older roller cam is for my 400 that someday is going to get built and installed into old 007.
Yeah, I read all your postings with interest. I only got confused when you mentioned the short primary pipes. I don't even know the specs on this cam. I bought it off a guy at work a couple of years ago when he decided to put a supercharger on his camaro. I think this thing has like .625 lift.
Hey man...if the Big G says not to worry! I ain't gonna worry!

------------------
GeneD
007
Melbourne, Florida

[GeneD]

MP,
If I threw that thing in the back of the Corvette, I would have to leave at least one six pack at home. I barely have room in that thing for my cigarettes!

------------------
GeneD
007
Melbourne, Florida