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-   -   No! Not My Cylinders (http://www.peachparts.com/shopforum/tech-help/81482-no-not-my-cylinders.html)

Dave Bunker 12-09-2003 01:51 AM

No! Not My Cylinders
 
Well, the one thing I didn't want to happen, in fact happened.... A while back I posted a note on pulling my heads, inspected the cylinders to determine whether to go ahead with new valves and seats. Got the heads back and found that I missed some major scoring on the front cylinder, all the way through the teflon. I don't know how I missed it. The block is a rap.....My motor as I have know it is dead..I need a drink!!!

inspector1 12-09-2003 07:58 AM

Re: No! Not My Cylinders
 
Quote:

Originally posted by Dave Bunker
Well, the one thing I didn't want to happen, in fact happened.... A while back I posted a note on pulling my heads, inspected the cylinders to determine whether to go ahead with new valves and seats... "

Huh? One doesnt have to pull the heads to inspect the valves or seats.

"Got the heads back and found that I missed some major scoring on the front cylinder..."

Why did you have to wait to get the head back to find major scoring in the cylinder?

"all the way through the teflon... "

huh?

"...I don't know how I missed it. The block is a rap.....My motor as I have know it is dead..I need a drink!!!

I dont follow your logic here, maybe you DONT need another drink.

Kestas 12-09-2003 09:08 AM

How does teflon play into this?

moedip 12-09-2003 10:05 AM

I think he is referring to the siliconized cylinder liner. BUT THE GOOD NEWS - the engine is not toast. Mercedes Canada sells new cylinder liners that an engine shop can press out the old one and press in the new one. The same thing happened to a friend of mine on his 420sel I could be wrong but I think the cost of the liner and the engine shop time was about $700 CDN not including reassembling the engine.- new piston with rings and the liner and the engine is still working great - 4 years later. It is a lot of work though. If you are interested go to Ebay - a guy there is selling a 420sel engine with low mileage for $1100 US complete. Either way - the car is not history.

moedip 12-09-2003 10:12 AM

The engine on Ebay is starting at $800 with no takers with only 5 hours left - item number is : 2446511394

If you are interested

Duke2.6 12-09-2003 10:42 AM

These series engines use cylinder wall technology that is a development of the process pioneered by GM/Reynolds for the Vega. The monoblock is cast from a high silicon aluminum alloy, and the cylinder walls are etched after final honing to remove surface aluminum, whilch creates a very hard silicon wear surface. Pistons skirts require an iron plating and three thin platings of other metals are required between the aluminum skirt and final iron film in order to achieve proper plating adhesion.

For field repair, the cylinder can be bored and honed, then subjected to a "silicon lap" to remove surface aluminum, which yields the same result as the original chemical etching process.

Other alternatives are iron or high silicon aluminum alloy liners that can be installed after the cylinder is overbored to accept the liner. If the final bore surface is the properly processed aluminum silicon alloy, a properly plated piston should be used. Iron liners only require a conventional aluminum piston without the skirt plating.

When I recently refreshed the cylinder head on my Cosworth Vega (very worn valve guides) I noticed some minor scoring on one cylinder's major thrust surface. The engine made excellent power before the work and I attributed the high oil consumption (about a quart every 300 miles) to the worn guides and poor OE seals. I decided to complete the head refresh (new guides and a new design seals) and install it without rebuilding the block. Oil consumption dropped to nearly unmeasurable, and all the power is still there.

These aluminum-silicon bore engines have some tolerance for scoring, but without seeing it, it's tough to make a judgement.

Duke

Dave Bunker 12-13-2003 12:41 PM

engine swap
 
engine block update. While all the suggestions are quite enlightening regarding reboring and having a sleve incertec, I opted to purchase an engine with only 100,000 miles on it with a new valve job, including all new retainers. I swapped one cam cause one lob in my old engine had scoring.. Im using my same injection with chain and guides from old engine. guides are new and so is the chain. The new engine had a chain break event and top end was done about 3-5 thousand miles ago.......new engine was out of the same year car my is.....soooooo, the big thing is I talked them down from $2400 to $1400. That's for a complete engine........I also rebuilt my trans while it was out....We dropped the new engine in yesterday and will hook everything up today and tomorrow...Ill post pictures later.....


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