What is the verdict on raising compression? Should I get the positions , ross 640 buck, or mill the head. FYI no matter what I have to get pistions I am going .080. So the really question is do I be a cheap A^& or do it right

If you do not see anything wrong with a question about "milling the pistons", you have a lot of reading to do before you pick up your first wrench.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I don't believe that's what he meant. I think he's trying to decide whether to mill the head or get custom, as opposed to off the shelf, pistons. At least that's the way I read it FWIW.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

I think what he meant was "mill the head or get new pistons that will raise the compression ratio." If, in fact, that was the meaning, and money wasn't an object, I would get the pistons. Being the cheap guy that I am, personally, I would probably mill the head. I don't know how much .080 pistons are going to cost either though, so it might come out a wash.

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Used to own:
'82 Dodge D150
Erson 270 Cam, O/S valves, mild port work, ~9.5:1 compression

Currently fighting with an '85 VW Cabriolet

My other passion

what I was trying to ask was Should I get custom pistions for the compression or mill the head .0100.

As I understand it, there are advantages to milling the block rather than the head. That's the route I intend to take.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

Go with stock .060 over pistons and deck the block for compression.....you need to cc the head to figure how much to deck the block....and you need to test fit the pistons in the block to get the right deck height....search ,,read, ,,,search,.,.,read.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

If you can get the compression you want by using a piston with the proper compression height, that is the best way to go. Leaving the head and the block decks as thick as possible helps the head gasket stay sealed.
Why .080?? Are rings available and easy to get in that size? (3.480)

If you want to go big on the bore and have lots of pistons and rings to choose from, bore .100 oversize and get to a 3.500 bore size.
DD

If you've got the bucks and need a forged piston then buy forged pistons. Mine with pins, locks, etc are costing me less than $500 from Venolia. The reason I'm going forged is because I'm also going with forced induction. If you just want higher compresion on a normally aspirated 225 I would deck the block if the engine is going to be torn down completely or mill the head if it is not. Also, +.080" is an odd oversize. You're much better off with a standard oversize as it makes rings much, much less expensive for your custom piston. If you want that big a bore go +.100" and use 3.500" pistons and commonly available rings. If you want to save a bunch of money then go +.060".

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Joshua

They are available. I would need to dig through my shortblock rebuild paperwork from the machine shop to find the manufacturer, but my machine shop (in Alaska) found .080" over (cast) pistons & rings for my '87 block.

I did verify the bore before bolting the head up.

-S/6

I was going to have ROSS make them $640

I agree^. Also, even tho we have seen many .100 over bores in high output blocks I still seem to want to keep my blocks as strong as possible. I would probably go with .060 over in a high compression or forced induction setup( my way) but as I said many have went on with the big bore with no problems.

I may also be tempted to get a piston that was alittle higher than I wanted and "mill the piston" or shape it a little to get the best flame travel possible. This may take some R&D and have to take the motor apart a few times after running it unless your just good ( which I am not) and know a lot on this type thing. If your building a high compression motor this with chamber work could help with pinging ,flow & power.


Jess

I live in las vegas and in AZ were the temp gets up to 127 f. The guy that is doing the machine work thinks that 100 over on a daily driver might have some over heating problems. He had one at 080 over. That is why 080

Ok, that's fair reasoning for staying .080" oversize, but what's the reasoning for spending an extra $180 for Ross pistons rather than Venolia?

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Joshua

hello again , i have been running sealpower(244np .080 pistions) and hastings(687 .080 rings) with no problems. they were 24 dollars canadian and order out of the US. i used these piston because they were the biggest stock piston available. they have the stock comp height so i milled the block, witch is the best way next to pop up piston to go , keep the combustion in the head . these part numbers are not hard to order even up here in newfoundland.thanks