One thought just hit me
 

Why didnt I have to resleeve when I rebuilt a Honda engine. This is not a point counterpont question intended to further the original question. I just remebered re ringing two gas engines with good results...I know Diesels have higher compression so that may be the answer...

Much of it has to do with the clearances which the book calls for between the piston and the bore...
On our 617's you are supposed to hone each cylinder to match the particular piston which you are placing into it...
Gas engines typically have more leway... and you have to factor in that many of those original rings or the ones you are going to put in are not going to last 300,000 miles...
In other words , the max distance between the piston and the bore on that Honda may allow a clean up hone and larger rings...and not be past the max clearance.
Since Honda does not sell Factory Shop Manuals and will not allow acces to TSB's.... how did you determine what were the go/no go figures ?

“improved geometry”
 

Is there an “improved geometry” connecting rod and piston available for the 603.970? Any idea what those would cost? Do they solve the bent rod issue?

Mr Leathermang, as I recall, I got them from someone who had the info
 

Mr Leathermang, as I recall, I got them from someone at the machine shop who did the heads and I honestly had no idea it was closed source. But this was back on an 81 Accord and an 85 Accord which might have predated the closed info mandate.

I know Diesels are a vastly different much more complex game. (Remember when GM tried to ocnvert Gas engines into Diesel?)

I had no idea Honda info was so secret.
Rebuilding engines is a fascinating topic. I am only about 3% into the 100% depth you need, To me its part analytical and part alchemy and I really wish I had known you when i started because I might have fulfilled my dream of blueprinting an engine.
When I read shop articles about the machining processes and calculations that go into rebuilding an engine, i am astounded that people out there have this knowledge

PS On the Honda specs i was just thinking--I would guess out in California, even on a 2005 model, some one must have got this info or they could reverse engineer it with all those tuners out there. I dont know much about that segment of the industry but my guess is that Honda might surrepitiously leak that info to someone or some son of a Honda executive would release it.
Anyway thats not my corner of the world or my thing, either.
Take Care--someday if I drive through Texas I'm going to knock on your door.

That's only 1/2 true. Their stuff isn't published in All Data, but they do sell good old fashioned paper manuals. A friend of mine bought a set for his new Accord Coupe last year.

Our two late model gas vehicles I don't service... a local legit mechanic does that... and he was the one who turned down some repair items on the 1992 Honda saying info was not available... Had to take it to the dealer.
On this old a car having only the original shop manuals with no updates for things found wrong and their corrections is not good.... I was surprised and went to check on alldata ... and sure enough Honda does not cooperate with them...

THe GM converted gas engine diesel is an urban legand.

No the GM gas engine converted to diesel was not an urban legend. There was an Oldsmobile V8 that was used as the basis for a diesel passenger car engine in the late seventies or early eighties. The Duramax diesel used in todays GM light trucks is a descendant of that engine.

The whole project was a disaster IMHO. The silliest thing about it was that at the time, GM owned Detroit Diesel. All they had to do was get a little engineering help from those boys and they probably could have built a reasonably good engine.

Ironically in the early versions that was in the Oldsmobile, the guts of the engines held up reasonably well. It was fuel system problems that plagued the engine the most.

Have a great day,

How do you figure the Duramax is a descendent of that engine? It was developed by Isuzu and very close designs have been produced for Asian medium-duty diesels for years. At least that is the information I have been presented in everything I have read. I was actually once told Isuzu originally got much of the design components from Caterpillar, then reworked it. But that I wouldn't put much stock in. At any rate, I know the engine design came from Isuzu.

Hello Don......
Yes there are revised parts for this engine .......
I still don’t understand why these engines have problems. The rods are shorter than previous models and its real beefy. I have another post that lists the differences…..I believe that cylinder sleeves were eliminated on this design. Im not quite sure how they did that....
The only thing I can surmise after a careful design analysis is excessive fuel after shut down. Possible fuel dribbling down from a bad injector and collecting in the cylinder. The other thought was….A diesel that wont start because of bad glow plugs or relay causing an excessive amount of fuel …..At such compression the excess liquid will bend rods.
But then again …..why number one cylinder.??
That seems to be the cylinder that everyone points too…..
May be there is more IP pressure at that injector for some reason after shut-down and fuel leaking past …….??
In any event parts are available on this site …and others. The cylinder head was upgraded as well.
You can see the differences in the head casting. I believe I have the correct number for the long block assembly. From MB…….Check with the local dealer.

"The whole science of machining," .....
 

"The whole science of machining," Mr. O'Rourke said. "It's somewhat of a dying art these days."--Article in NY Times today

I used to read those Engine Rebuilder Shop journals and magazines at the machine shops when I was waiting in line back in the 80's. They had articles explaining why the block had to be counterbored a certain way or milled another way. Now you can hardly find them.

Maybe its because with more and more Robotics in the assembly line, engine rebuilding is becoming less of a trade? I don't really know why. Most kids are willing to "tune" their cars with a laptop, but I dont see many rebuilding them or many cars on jackstands anymore..

PS the best designed engine I have seen is the Volvo B230FT
 

in its 1990 on variations and which runs stock at 165 hp but has connecting rods and a block which can take up to 455 hp easily..I can say this because having only seen 5 or 6 engine types my knowledge is limited...


I was wondering if Leathermang can give me input on this and what other great engines are out there. I always buy my cars for the engine reputation mostly...

On the subject of great engines...

Nissan L28ET. More cold air, more fuel, factory stock engine rated at 180hp can be safely and reliably run to 400 hp (2.8 liters). This engine was introduced in 1981.

I only have direct experience with the Nissan. However many similar engines do well, mostly factory turbo engines, as they are built to take it. Keep heat under control, and turbos increase torque rather nicely, making tons of power within the factory redline. Toyota 7MGTE, 2JZGTE and 1JZGTE, Buick GN, Mitsubishi 4G63 all completely bullet-proof and all capable of 400+ hp in factory trim.

Edit: 4G63, 1st gen, eclipse & talon.

I am afraid that if I say anything in reply to that question that my age and frugality will show....But I will....

Favorite engine of all time.... 1800 pushrod Subaru (1980-84 )
Great engines I have owned (multiples of) 318 chrysler and the 225 slant six.
Other great engines... most any Toyota or Honda.

225
 

I had a 1962 Valiant with a Slant 6 someware past 220,000 mi......
My first rebuild leathermang...
A great engine!