65GS.com - Buick Gran Sport Enthusiasts!
General Discussion => Q & A => Topic started by: gssizzler on April 16, 2016, 11:48:59 PM
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My buddy also asked about pistons to! I know about forged ones probably not in the
Budget! Egge and sealed power seem to be the next and other choices! Ideas and opinions on these!? Thanks guy's :headbang:
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I assume he needs a whole set....standard, 0.030 over, what size? If he's got a problem with one or two standards, I've got a couple that were removed from my restoration engine.
I put a set of + 0.030 Sealed Power pistons in the rebuild.
Chuck
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My buddy also asked about pistons to! I know about forged ones probably not in the
Budget! Egge and sealed power seem to be the next and other choices! Ideas and opinions on these!? Thanks guy's :headbang:
Carmen Faso has every part your friend will need for a rebuild. Prices are reasonable also. Only does business via the phone. If you need his number let me know.
Would stay away from Egge.
Dan
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Thanks again ,was hoping you guys would have some good advice! and good experiences! Didn't no which way to go on these as the motors in my GS's have the old Trw's I believe in one and Badgers in the other! They don't make either anymore!
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What some MAY be missing is the fact that normally ANY of these cast pistons, IF you pay attention to the details, will almost NEVER give you anywhere near the original stock compression ratio. Now mind you the BEST I have EVER measured is 9.75-1 from the factory. This is with the piston in the hole about .040" which is RARE. Most are in the hole about .055", now 9.5-1. Most of the cast replacements are in the hole .065" +. Now about 9.3-1. Add the thicker Fel-Pro composite gaskets at about .039" compressed you lose an additional .77-1 compression. Now your at 8.5-1. I was just told the Best gaskets are about .050" compressed. I think they are advertised as .033" compressed. Unless they have diff. ones available. Now the ratio is even less. Then the con rods are re-conditioned which makes them shorter by .001"-.002" To get back some of this lost static compression ratio there are a variety of things to do. 1st. is decking the block. At an additional cost of course, cutting the heads more to make a smaller combustion chamber, at an additional cost. Now this EXTRA material removal will likely end up with port mis-matching, especially with the intake manifold & water manifold. Now you have the possibility of the outer edge of the pistons domes coming into contact with the head. You need to take off additional material from the edges of the domes & this will lower compression even more. Then you have the additional cost of the original shim steel head gaskets which are becoming more not readily available as time goes on & will become more costly in the future. Then something MANY don't even think about is the squish/quench area. From the factory, normally, they are .055" in the hole & with the shim steel gasket at about .015" compressed the quench/squish area is .070". Our "Nails" seem to run best with about .025"-.050" squish. Ever wonder why one "Nail" ran better than another when they were new. It probably had something to do with the piston sitting in the hole closer to .040" as opposed to .055" as is normally found. When the squish is correct the engine has a better chance of resisting detonation problems. Some times you cannot hear this as it's so slight.
Now after doing all of this to get things as correct as possible, with the cost of the pistons, rings, additional machining operations & the cost of shim gaskets your pretty close to the price of my custom forged pistons, including rings. Then you have the additional insurance that a forged piston has over a cast piston. Plus the additional features that have been designed into this forged piston.
Each set is built to each individual engines specs. Unfortunately I NEED ALL the specs. Once I have all the specs it is about a 2wk. turn-a-round. Single sets cost additional $$$$ so getting five sets done at one time can be a savings.
Tom T.
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Tom,
Thanks for the post(that was a lot of typing with info worth reading). I did not rebuild mine and I do not personally know the guy who did. It was built years ago and test ran a few times,but I was wondering if there is any way to guesstimate the compression ratio on an assembled 401. I do have some receipts with piston numbers and bore size and I do not believe there was any decking.Dan
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The closer to stock compression would have the cranking compression at around 175-200pds. Of course this does NOT take into account the type of cam being used. On MANY stock rebuilds using a standard replacement cam, usually from CMC, you end up with somewhere around 120-140pds. cranking compression. This relates to around 8.2-8.5 with the quench/squish area being MUCH MORE than the recommended max of .050". Even with the available fuel today we can run a closer to real 10.0 without any adverse effects with a pretty aggressive ignition timing curve.
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Dear Tom and fans of mid-60s Buick engines,
Thanks for explaining your motivations in coming up with your own pistons for these engines. I had read the available pistons were crummy, but I didn't understand why. Even if I upgraded to a later Buick engine, I do have a soft spot for the 1965 engines. Should I run into anyone trying to rebuild one of these engines, I'll definitely recommend that they get in touch with you! :thumbsup:
Cheers, Edouard :occasion14:
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Thank you Edouard. ANY recommendations from ANYONE is appreciated.
Tom T.
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The closer to stock compression would have the cranking compression at around 175-200pds. Of course this does NOT take into account the type of cam being used. On MANY stock rebuilds using a standard replacement cam, usually from CMC, you end up with somewhere around 120-140pds. cranking compression. This relates to around 8.2-8.5 with the quench/squish area being MUCH MORE than the recommended max of .050". Even with the available fuel today we can run a closer to real 10.0 without any adverse effects with a pretty aggressive ignition timing curve.
Thanks for the reply,
I am going to do an oil change and pull the plugs just to get an idea of where I'm at. The engine sounds healthy and I am happy with the throttle response,but I was just curious as to running pump gas with additive or buying better fuel.