![]() |
How true is the adage that you have to resleeve a block?
I was told by several good people that you have to resleeve a block and replace the psitons with oversize pistons once you pull the pistons because the block bores wear in an oval fashion. It makes no sense just to pop new piston rings on there. Is this true? I am rebuilding a Diesel with Mercedes shop forum help right now.
On my 240D I didnt resleeve and I used Deves rings ant a year later it blew oil like crazy. On my Volvo diesel rebuild I lost no oil. |
resleeve yes new pistons not necessarily.depends on original piston condition.any good rebuilder would be able to measure and advise.dont recommend the old "berlin rebuild" that being rings only.i did this on an old volvo(vw) diesel.it worked well but the engine was noisy.
|
Berlin rebuild. :)
Who cares if'd be noisy, these cars are noisy anyway. |
"was told by several good people that you have to resleeve a block and replace the pistons with oversize pistons "
The economic value to a system where you can resleeve the block is that if you have well made pistons... then you go back to original sleeve size and reuse the pistons... This is particularly important with the Turbo Mercedes because the pistons are so expensive. The sleeves are only about $35 dollars Each... pistons for a 5 cyl can run $1000... So new sleeves bored to match your piston, and new rings (even special one from Deves to compensate for ring land wear ) is the sweet point for doing it right and at reasonable cost. |
I thought about this before I jumped and went new pistons (stock, not oversize) and new sleeves. The sleeves need to be precision bored and honed. I pressed the sleeves out and in myself with a tool I made, and cut down the tops of the sleeves to match the block deck. If your pistons are OK, you are in luck, but mine weren't. Deves makes a special set with overwidth top rings, but my ring lands were too worn on the second groove also. The last I talked to them I suggested that they consider making a set with 2 wider ring sizes as there would be a market for it. I got my set of Mahle pistons and rings from Rusty for $675 but the prices on those have gone up a LOT since then. Carrameow, I know you can do it, but that motor is a lot of work. Good, used engines take less time.......
|
If the cylinders mic out within spec, replacing the rings would be acceptable. The likelihood of that being the case on one of these engines is probably wishful thinking.
Secondly, if cylinders do indeed need attention, you don't HAVE to replace the liners, you can bore the liners to an oversize just as you would with any engine then use oversize pistons. The other option would be to resleeve which must be done by a machine shop. They replace the sleeves, cut the top with a boring bar and then finish to size if necessary, then reuse the original pistons. This is my least favorite approach. Although it is typically the least expensive, you are reusing the second most highly stressed part in the engine, the piston. My $0.02, |
" reusing the second most highly stressed part in the engine, the piston."--Larry Bible
Larry has said this before... but I still can't figure out where he got this concept. It violates the physics of the situation with regards to Aluminum... Aluminum is incredible strong in tensile strength... period.... and even more so if you look at it with regards to its weight.... It is like fiberglass in that respect... and in another... it is pretty much good until it is bad. It holds all it can then completely gives way... It does not typically weaken just from sustained use. If this concept were valid I propose that the MB Factory shop manual would say " replace on principle" as it has no qualms about doing with regards to other parts... whether they spec out correctly or not... because they are the type materials which are prone to weaken slowly and then give way. This is where dial indicators, good magnifying glasses, and care in the inspection of engine components comes in... after the engine has been taken apart and you are making the decisions concerning what needs to be replaced, refurbished or whatever... If the aluminum pistons spec out ok... or can be made that way with minor machining as with the wider rings.... there is no reason not to use them again... and many dollars worth of reasons TO use them. |
sleeve or just wipe it!
When I rebuild an engine I always replace the pistons. The rods can be reused and / or reconditioned in most cases. Cylinders do tend to wear slightly out of round and on a taper. However To do it right…… the cylinders should be bored and honed. Thus, the need for replacement oversized pistons. 30 oversized will clean up most cylinders. In some cases you can sleeve the cylinders when there is excessive wear. Some manufactures allow for sleeving. Or if the engines are sleeved from the factory….Press in a new cylinder…
I have rebuilt a Ford 460 V8 In reasonably good condition. I did not bore or hone out the cylinders at all. I simply cleaned the pistons slipped on a new set of rings as per the manufacturer’s instructions. 45000 mi. later it runs great with no oil burning at all. It certainly depends on the condition of the block. Check the cylinders with inside micrometers. See if there is a difference side to side and then 90 degrees side to side clearance and check for a taper between top and bottom. “On my 240D I didn’t re-sleeve and I used Deves rings and a year later it blew oil like crazy.” In this case the rings did not seat themselves. Rings come with a soft power coat layer on the mating surface. This wears away quickly to seat the rings. Some times if you hone the cylinder it just wont work. The rings wont seat. The cylinder needs to be near perfect. Understand that the now newly scratched honed surface will cause the soft powder coat to wipe off much too soon allowing for a fast break-in 20 min or so. So if the cylinder is slightly off the rings wont have enough time to break in. You will have better luck just wiping out the cylinders and replacing the rings. The smooth cylinder walls will allow for a gentile break in ….about 500 miles. The cylinders do need to be in good shape for this process. |
I will need this space....
|
Quote:
I was thinking about your statements regarding the pistons. The logic holds. Is anyone aware of a piston that has fractured after extended use in a 617? I would be interested in a situation where the pistons were reused after an overhaul and did not go the distance. |
Sometimes I actually research the facts I use to support my opinions...and I knew I needed time but did not want my reply to be away from the subject post.
|
dont forget to
Don’t forget to have the tops of your pistons coated in ceramic it is cheap and you can increase fuel flow big time with out burning a hole in your piston. Furthermore it gives you a good excuse to put in that big intercooler while your at it have the turbo rebuilt with ceramic bearings and have the fans cut and bent for Evan more power so you only get 13 MPG you will have the only diesel MBZ that you now have to make a posi traction rear end to hook up all that power to the ground. And most important remember you can buy fiber glass fenders hoods and trunks for these cars.
Dave S :) |
piston ..... sets....
When you do research on the subject of pistons you will find that Mercedes coats them both top and sides with a protective coating. This coating will wear off …. Check for the piston skirt “scuffing” the cylinder wall. If it is, then replacement is necessary. If you reuse the pistons do not clean them ! Simply wipe them off with transmission fluid. If the “cross hatch” is still visible in the cylinder and there is no scuffing you can try just new rings. This is a clear indication that the oil was changed at regular intervils and that there is minimum wear in the cylinder. Also check for a ridge at the top of the cylinder a deep ridge indicates a cylinder that is well worn.
There are other after-market parts available as well. Usually when you purchase a replacement part you also get a “revised part” meaning an improved design. I would recommend checking to see weather or not there are improved designs available. From the factory or as an after market product. Ahh ....yes, newer designs have a ceramic coating. Older designs have a graphite coatingThere may be Matched parts available such as a piston / ring “set”. Also be aware that there may be a specific connecting rod that matches only that piston with “improved geometry”. A piston and rod set. Typical of most racing applications. This is also true of the 603.970 diesel. |
" If the “cross hatch” is still visible in the cylinder and there is no scuffing you can try just new rings. " ---Anthony Cerami
Have you ever seen this concept written in a manual or rebuilding instructions for a diesel ? My rule is " New rings , New crosshatching ". The function of crosshatching is to aid in the seating (wearing in ) of the new rings. The exception is some air cooled small engines where chrome rings are available for rebuilding which are hard enough ( and typically work in aluminum bores ) to cut their own space. " If you reuse the pistons do not clean them ! Simply wipe them off with transmission fluid." Cleaning pistons during a rebuild involves getting any carbon off the top and cleaning the ring lands so that new rings can function properly. The instructions in the shop manual are very specific. |
Its humbling
I feel like one of those teenagers who puts a spoiler on his Honda Civic, boy I guess I really didnt know that much..but then I always was a question asker, not a question answerer.
I do plan to rebuild this engine, because there will always be 123's I can stick it into. Just looking at it apart gives me a High. In the meantime I went to my indy and bought one from a wrecked 300D....and bought a car to boot. talk about shopping like a woman. I came home with a SAAB 86 Turbo 9000 5 speed for $400.00. The motor is good and so is the body, but it needs a lot of work... |
" bought one from a wrecked 300D....and bought a car to boot."--Carrameow
I think that is great.... now you can rebuild this one with no time pressure. |
rings
leathermang .....
I agree with you. However you do have a choice. As I mentioned you can just just replace rings under the right conditions. As for the pistons ...did you red this in the manual... -The piston top is covered with an aluminum oxide coating. -The piston skirt and the top land are graphite treated. That means no scraping , brushing, scratching, I never follow the rules. I make new ones ........ |
Quote:
|
Quote:
You can probably get a machine shop to stick the micrometers in the cylinders for free 'cause they want your business. If you can find an engine that is not worn-out and that has a reliable service history you save big money. |
crosshatching
That is correct......Most engines there is no cross hatch visible at all. And there is a significant ridge as well. There just worn out..... 90 percent of the time they need to be bored oversize. In some cases after a 30 over bore the ridge will still be present. In that case it needs to be cut away or it will break a new ring as soon as you start it.
"The function of crosshatching is to aid in the seating (wearing in ) of the new rings” This statement is partly true. If you read my previous post carefully ...... As I previously stated, it is the rings that have a coating for break-in so the cylinders need to be a very smooth finish Honing the cylinders will achieve the smoothest surface possible. An engine that still has a crosshatch visible with no ridge or very little, would be a good candidate to just replace the rings. That all I’m saying…… Ok so use a little “Sctoch-brite” and make your own rule… The hone will tear, fold, and rip the bore finish if not done correctly causing premature failure. Synthetic oils will not allow the rings to seat so you can only use dino oil for break-in. "If you can find an engine that is not worn-out and that has a reliable service history you save big money." Thats all I'm sayin dude .................... |
Anthony, the more you post the more it looks like your experience has been with American gas engines as compared to our 617 diesels...
|
Crosshatching does not provide the "smoothest surface possible". The walls need to be rough with a cross-hatch to seat new rings. Polishing will provide the smoothest finish, and NO ONE polishes cylinder walls to install new rings. If the walls are polished, it doesn't matter what rings you use, they will never seat. Perhaps the only exception to this would be in the manufacture of a NEW engine where the cylinders can be specified perfectly round, and chrome rings can be used for long life. But I'm not sure about that.
|
OLD300D, You are absolutely correct... the statement by Cerami "The hone will tear, fold, and rip the bore finish if not done correctly " is actually close to the Advertizement which goes with the wire abrasive hones... the idea IS to tear the wall (in a controlled fashion )...and the combo of that and the crisp surface on the edge of the new rings Wear in together...
If you start out with a smooth bore it will never seat the rings... I have known other people who thought they made their own rules... they would do things like install rain gutters without regard to slanting them downhill... and would spend the summer wondering why there were mosquitoes buzzing around their head all summer. |
Is anyone aware of a piston that has fractured after extended use in a 617? I would be interested in a situation where the pistons were reused after an overhaul and did not go the distance.[/QUOTE]
Yes, I have in my boxful of mechanical memorabilia, a piston from my 240D with ring land failure and other cracking. It came out of the original engine after 380,000 miles. There are a number of people who have posted on this forum over the years that they have reused pistons in a resleeved engine, but I personally feel that it's not worth the risk after seeing that piston. If you are dealing with a standard bore engine, you can bore the original sleeve oversize and replace the pistons. The pistons will indeed be an added significant cost, but the machine shop bill will be less since they will simply bore the block, rather than replace the sleeves and then bore to fit. A piston in a diesel engine lives a really tough life. Rather than a CR in the area of 8 to 10 to 1, you are dealing with a CR of 18 to 22 to 1. In addition to that the diesel piston deals with IMPACT pressure rather than the relatively gradual pressure increase of a proper running gas engine. You can hear that impact pressure. It's heard as diesel knock. My $0.02, |
Quote:
|
honing
OLD300D, You are absolutely correct...I agree. I have rebuilt many engines in the past This process is critical. After you hone a cylinder check it out with a high migification eye loupe. Youll see what I mean.
Ok so now that we beat this to death..... Who is gonna help pay for this sleeve , bore, hone job.? |
Quote:
|
LOL.......
Ok no problem ...Im speaking to the grop. Ok my shop is available ...Hoist, Engine stand....etc Carrameow Is a stone throw from me ...............Lets do this ...... |
You guys with all this talk of new pistons, weather to re sleeve or re ring, has got me thinking about rebuilding the 616 I have on the stand. I bought new O/C pistons and had new sleeves bored too fit on the one I did last. Like someone has already said, "something nice can always be found to put it in" :D Anyway It seems new pistons would be a good idea if your gona do all the work of a rebuild, not a huge expense with a non turbo.
Lots of good input in this thread, Thanks |
Billrei, Earlier today you said "I guess I will try some Trans-X snake oil at some point and see what happens."
Since the concept of dissolving Varnish built up in the tiny holes in a transmission is very simple....and that is all the Trans-X is proffered to do... and since as far back as 1975 it has worked for me , sometimes dramatically, your " vouching for " Anthony is suspect. I will put up my position with regards to what Anthony said using logic and references from accepted sources... My first point is that the Factory Shop Manual is not for putting the engine together WHEN NEW... It is for rebuilding....... and since it is for rebuilding.. the very specific specifications which are listed are meant for making the determination as to whether one needs new pistons or not. And the cost of Turbo Pistons is not a small matter when building an engine. I notice that those suggesting using new pistons ( without regard to whether they pass the specifications listed in the manual ) don't suggest that one take apart an engine when it reaches a certain mileage.... If they were really worried about some etherial ' stress' which can't be measured... and certainly we have not had a swelling of posts saying that their ' old' pistons fell apart...I would remember that and we would have spent a lot of bandwidth on it... |
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”
Quote:
|
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. |
Quote:
|
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... |
Quote:
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.
|
Quote:
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! |
Quote:
I think you could easily get 300K out of them if you just changed the oil regularly. Most people did not and they still went close to 200K. I subsequently bought a Plymouth Volare for my father with the same engine/trans package. A basic vehicle without any a/c or power anything. Cost was $4K in 1980. It would still be running fine if my sister didn't total the damn thing. :( |
That 225 allowed for a low hood line but lots of torque..
It is the longest running single production engine ever... I will bet yall did not know that it is still being produced... it is used in things like forklifts and marine applications.... |
Quote:
|
I had a slant six in a boat. They called it a Chrysler Marine Six and it had a Volvo outdrive. Fun boat, not good on gas. I always wanted to put a turbocharger on it.
|
Recycled
for new members.
|
All times are GMT -4. The time now is 11:09 AM. |
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website