Pagoda SL Group
W113 Pagoda SL Group => General Discussion => Topic started by: n/a on June 26, 2006, 16:09:51
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Hello! Congratulations to all of you in this excellent Pagoda Group. I am posting because we need your knowledge and help. Thanks in advance.
We have two 280sl pagoda.
The first one is a five speed manual 1968. The restorer is doing the motor work and he need to change the pistons. The car came with flat pistons. We only get from Mercedes stepped pistons, and they say they will work fine. This car cames with the early cylinderhead.
The second one is an automatic 1970. Motor number 130 983 12 00 92 45 This car is almost an stage 1 car. Really wonderfull. While driving this car the motor loosed compresion and stoped . The restorer opened the motor and he found a burnt cylinderhead gasket, and a curious cylinderhad:
1.- 1mm less in its normal height
2.- really bent
3.- and the most important!: In the chamber there are some losses of material in diferent chamber locations ,only one of the chamber is normal.It seems like somebody would have been removing the material or it has disolve itself. Some of the material disolved is in the cylinder walls. We bought a new cylinderhead and now must change only the rings or the pistons and rings. This car came with stepped pistons , the arrow pointing forward.
Mercedes Stuttgart only recomends stepped pistons.
We assumes:
1.- That both car have been motor repaired previously and the pistons could be not stock.
2.- We sent an email to Dan Caron (thanks very much Dan) and he recomends flat pistons and told us his oppinion was that diferent pistons are for different compresions.
3.- Our seller tell us he cant find original flat pistons in Germany
4.- We readed in a W·113forum thread about the manual removal of material from the cylinderhead chamber to compensate the high compresion ratio in any of the chambers when using a cylinderhead with reduced height. Or we understood that from the reading!
4.- In the technical Mercedes W113 book it seems that the arrow on the top of the steped piston must point back and not forward. ( Using the late cylinderhead design)
So, we have some doubts:
1.- Does the cylinderhead design (early and late) affect the selection of the piston to install?
2.- In the stepped pistons the arrow on the top must point really forward?
3.- What could be the cause of the loosing of the material in the cylinderhead?
4.- Would you recomend stepped or flat (if available where?) pistons?
5.- Using stepped pistons in the second (late cylinderhead) car can cause a reduction in compresion and performance?
I apologyze for my english. Thanks very much and congratulations for your excellent site!
Luis
280sl ´70, 190sl ´58, 600sl´05
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Luis,
Your English is good enough that we understand you, no need to apologize.
For sourcing your pistons, we have a large database of parts suppliers located around the World:
http://www.sl113.org/data/show_table.asp?table_name=usr_parts_and_service_suppliers
I'm sorry I can not help with your technical questions, I'm sure others can help.
Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420
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Luis,
Mahle is the brand of the pistons you are looking for. They are available in standard diameter and over sizes to allow honing or boring of the cylinders. Try sales@millermbz.com and ask for availabliity and price. They won't be cheap.
Once you have been here a while you'll learn you can count on Dan's knowledge.
Bueno suerte.
Ray
'68 280SL 4-spd Coupe
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Luis - check with Metric Motors, who remanufacture these engines but also sell the parts for that, including pistons and ring sets. They offer sets on Ebay at the lowest prices you are likely to be able to find currently:
http://www.mercedesengines.net/
Send me an email and I will send you a compilation that I made from thousands of posts here on engine rebuilding for the Pagoda.
Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic
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The arrow on top of the piston must point toward front of the engine. This is the case for any engine. The stepped or "half domed" piston would raise the compression somewhat as compared with a "flat top" piston. I can't speak to which type is required for a specific engine.
Good Luck!
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Thanks very much to all of you. I think we are going to install the stepped version in both pagodas. The only reason will be that both cars come with that pistons and Mercedes Stuttgart tell us to install them. We have still a lot os doubts about we are doing and why are we doing it that way.
I will post this weekend some pics to share with all of you. I think they are very demostrative.
Thanks again from sunny and hot Madrid!! You are great!
280sl ´70, 190sl ´58, 600sl´05