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#16
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#17
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$300. Prechambers $170. Valves $100. Guides $ 60. Seals $110. Head bolts $350. Grinding of seats, installation and honing of guides, installation of seals, pressure check of head, paint. $ 50. Gasket set After adding it up, it's actually more than $1100. The prechambers typically have the shaft that supports the ball start to wear out and become loose. Metric strongly advised against using them again........probably wouldn't go 100K. |
#18
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actually
we have usually reused our pistons. and then if you put it all back together with the parts coming back from which they came, it will still be balanced.
i did pay to have one balanced. the balancer said "that was a waste". it was already balanced. tom w
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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC] ..I also have a 427 Cobra replica with an aluminum chassis. |
#19
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Also when you balance an engine don't you match the counterweights to the pistons being that the piston is much more sensitive to modification? |
#20
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#21
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I didn't spend quite that much because I reused the intake valves (about $85. or so). Like I said, if you don't add up every item, it can easily get way out ahead of your thinking on costs. |
#22
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There was somebody on the Vintage Forum awhile ago who stumbled upon an abandonned rebuild of 1967 MB 6cyl engine with pistons and rods just tossed in a box. Not knowing the original arrangement to the engine, it was just a box of junk. |
#23
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re pistons
no they are not machined differently in bore, but they are matched and balanced with the rods and crank. i have never watched them do it so i dont know exactly what is done. i did however match my 51 caddy pistons myself at the machine shop, using a drill press and a paint scale. there is a thick place on the skirt of the piston that is for drilling them out to balance. i just matched them all so they weighed the same.
this is not what a professional balancer does though. i am not sure how i knew to just match the pistons. i suspect my favorite machinist told me to do it that way. it was silky smooth when done. tom w
__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC] ..I also have a 427 Cobra replica with an aluminum chassis. |
#24
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They grade pistons for size. They do that to cut down on manufacturing cost while retaining close tolerances. They will measure a bore before assembly, then pick a piston grade that corrisponds to that diameter. For example, the manufactuing tolerance on a 90mm bore can vary symetrically 0.5mm (89.5mm to 90.5mm), so you will also have pistons sized 89mm, 89.5mm, and 90mm and never have a clearance more than 0.5mm but never closer than 0.25mm. They can do the same thing with main bearings, rod bearings, and things that would normally have to be held to a much tighter tolerance as well. There are two aspects to balancing an engine, rotating and occilating. For rotating you can take it to a specialty machine shop that specializes in balancing like I did. They measure the masses of your piston and con rod assemblys and mount weights coorisponding to the masses measured onto the connecting rod journals, spin it and the machine tells you where to add/remove weight from the counterweights on the crank. There is quite a bit more to it on how you decide to take out/add weight as well. You want the counterweights to overcompensate for the rotating mass because it helps prevent the crank from bending and putting unnecessary stress on the mains, but you don't want it to be to far out because vibration will become excessive. As for ossilating, you do what you were talking about and match piston weights. Matching piston weights is important because you use pistons moving in the opposite direction to counteract the forces of others. You typically don't have to do this though because they are usually cast/machined to a toleranced mass. Matching con rods is less important because most of their mass is rotating instead of ossilating, but I suppose its still makes some difference. Last edited by imdavid28; 01-26-2006 at 02:05 AM. |
#25
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After looking at how much a rebuilt 603 short block goes for, I think if I ever go that route a brand new one from the local MB dealer is the way to go. 4 year warranty and about the same price.
New factory stuff is a known it lasts a long time, rebuilt stuff is an unknown.
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1999 SL500 1969 280SE 2023 Ram 1500 2007 Tiara 3200 |
#26
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If you can do the work yourself, you can do a pretty good job for about $2,000 providing that there isn't a rod sticking out the side of the block or some such.
Have a great day, |
#27
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After going through last night and pricing things out to do it half as good as I want, it came out to be more expencive to buy those parts and put it together than to buy a long block from the junk yard with 87k on it. Decision: done.
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#28
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Don't ever expect a used engine, regardless of mileage, to be the equivalent of a properly rebuilt engine. With a used engine you are rolling the dice, period.
Best of luck with it, |
#29
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yep
i would be a lot more comfy with a used engine if bought in a shaggy car that i could drive and see how it starts and runs.
i bought a 76 300d this way for i think 600. it was very faded with shaggy cloth seats but ran very well. buying from a junkyard gives me the willies. i would only do it if desparate. tom w
__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC] ..I also have a 427 Cobra replica with an aluminum chassis. |
#30
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I can't justify spending so much on rebuilding the engine though. Yeah sure it will last over 200k, but I don't think the rest of the car will. Besides, how much can a car with 400k be worth? I imagine no one in there right mind would buy something with that kinda number on the clock. |
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