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petermerle
Expert
Date registered: Apr 2006
Location: Cape Town ( deep south )
Vehicle(s): W460 *1, W123 *2, W124
Posts: 1315
| 300GD block repair?
A few months ago I decided to check compression pressures on my '82 300GD and found cyl #1 very low ( 7.5 bar ) , others all over 16 bar . Oil consumption was arround 1 l/1000 km . Engine otherwise ran well , started well etc. I decided to take head off and found a crack between the two valves on #1 and also in the exhaust port of #2 . other cylinders had evidence of head repair. I sourced another head as the engineering shop says that repair are seldom successful. The sleeves on 1 and 2 were removed and there slight corrosion on the block of #1 was found. This I believe came about as water entering combustion chamber managed to get out between sleeve and block. The engineers suggested that I use another block as repair which involves boring block oversize and then inserting another sleeve and then fitting the "normal" sleeve within that sleeve. The wall thicknesses are pretty small so we want to avoid that one. I was wondering if there is no other way to repair this , perhaps by removing the corrosion as much as possible ( sanding ) and then applying some compound to repair area such that the sleeve will still have intimate contact with block?
Peter |
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amzimmy
Elite Veteran
Date registered: Apr 2006
Location: South Africa/Italy
Vehicle(s): GD300 1981, Alfa GT 3,2 V6, Alfa Brera Q4 3,2 V6.
Posts: 850
| RE: 300GD block repair?
Peter, once the block and the head have cracks there is no other real solution and "bite the Bullet". I would suggest you find a second hand engine 617 even the car one and have that refubished with perhaps a new head, then you can easely open/free-flow all inet and outlet ports, work on the engine and then once you are ready you just swop and you will have an engine that will last you for an other 400 000 km or more without problems. I have done this and all in all I have spent, including the new second-hand engine (found in a scrap yard for R2k), new pistons, crank shaft, new head, valves and camshaft including tune-up and freeflow about R28k and I have already done, with the new engine, 200k km and still going strong.
Repairs like you mention are what most of the people do is for "re-sell" purposes only, to just get the vehicle going and then ged rid of it!
amzimmy  |
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petermerle
Expert
Date registered: Apr 2006
Location: Cape Town ( deep south )
Vehicle(s): W460 *1, W123 *2, W124
Posts: 1315
| Re: 300GD block repair?
Yes , I did get a good used engine and made good progress untill the dowel pin on the block next to #4 cylinder took a knock and resulting in a distortion to the cylinder after all the machining/reboringb! I have since got another subassembly ( in case that block is condembed ) BTW the sub assy cost my 3.3k and thats just the bare bones ( no vacuum pump, inj pump )
PEter |
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