Author Topic: Engine Restoration Question  (Read 3814 times)

Bernd

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Engine Restoration Question
« on: March 29, 2010, 15:38:20 »
Question for the engine experts on the site:
I disassembled my 280SL with about 49,000 carefully driven miles on it in 1991. The choice to redo the engine was not due to problems with the engine or excessive oil consumption During that time I took the prescribed measurements per the BBB instructions (see attached table) of the cylinder bores as well as the bearing tolerances. Given the results of those measurements at that time I opted just to rehone the bores, as the tolerances to me seemed very good and there were no scores in the cylinder walls that dictated more drastic actions. I purchased new standard rings and bearings.
In the process of finally getting the car back on the road, I will once again disassemble the engine, doublecheck all measurements, lube everything and replace all the seals. My question is as follows:

What would the experts recommend I do?
some options,  A) if all checks out, stick with what I got......hope the thing starts up if 1000 other things work
B) take the block to a shop and have them rebore it to repair stage 0, buy new rings and pistons, leave the bearings
C) Leave the cylinder bores and just do the crank and bearings,
D) definitely do both?

By now most on the forum know I am a do-it yourselver, but my budget now definitely allows me to have things that are out of my league done by a pro.


JimVillers

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Re: Engine Restoration Question
« Reply #1 on: March 29, 2010, 19:24:17 »
If the cylinders are within specifications, I see no reason to bore the cylinders and replace the pistons.  Inspect the pistons, especially the area around the piston rings for cracks.   The cylinders need to be honed to break the glaze so that the new rings will seat themselves.

Likewise, if the bearing journals look good, just polish them and install new standard bearings.

You are very lucky.
Jim Villers
190SL, 230SL 5-Speed, MGB 5-Speed, MGB GT V8 RHD (real MG), 2016 SLK

Bernd

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Re: Engine Restoration Question
« Reply #2 on: March 29, 2010, 22:03:35 »
Hi Jim

Thanks for the reply! If you see on the bottom of my posting I have a word document with my engine measurements. Visually everything was perfect at the time, and the specs are before honing. I am leaning to just polishing the bearing journals as well. It's just that before I decide to leave well enough alone, while I still have the engine out of the car, it would not be too difficult to get the block done at a real pro shop.

Bernd

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Re: Engine Restoration Question
« Reply #3 on: March 31, 2010, 14:16:10 »
Still hoping to get some input on the specs of my block I posted.