Like what the title says Any? Worth removing engine and doing it? Speed pro forged Pistons like 40-50 in hole Drivability? Better combustion w 93? 73 block n heads which have bowls only done and comp 278 xtreme w performer qjet and doughs headers 1 7/8 w 3 inch exhaust. 2500 stall 342's
No problems Had block minimally decked The shop offered to cut it to 0. I reused push rods and rockers the way I did it. I know geometry changes
Even cut of .006" will not effect The geometry worth fretting about ! dont forget that the ratio of the stamped steel rockers is nowhere near being dead on!
If you did have it 'zero'ed', you'd have to check valve to piston clearance since the pistons will now sit closer to the valves. If your pistons have valve notches in them, odds are good you're safe. If your pistons have a 'quench platform' on them, bringing them closer to the head will create better quench, permitting higher compression with the same octane fuel. All this can add up to more power, of course--but is it worth it to you? Is the engine pinging on the fuel you're using now?
That's the only advantage. Tight quench increases turbulence in the chamber before firing. Rocker geometry won't change since the rockers and valves are still in the same position whether or not block gets decked 0.006" or 0.050". You will need the correct pushrod length to keep lifter preload in spec. Disadvantages.... Intake may need to be cut to fit, new pushrods, and the other items Gary mentioned. You're likely not concerned about machining off the engine code and vin. Options: earlier heads with smaller chambers will increase CR but not improve quench. New pistons with proper compression height, Longer rods?, 0.040" Stroked crank?.......... likely not budget-friendly options.
Interesting read, a lot of that about the machining sounds familiar like I wrote it myself. uzzled: Good stuff though, I wonder when that was written? Great minds think alike I guess. Derek
I figured JW wrote that, I was wondering when he wrote it? Today is the first time I read it, a lot of what was written about the machining is what I wrote in a thread trying to educate a certain body guy about machining costs vs. buying better pistons, unfortunately that thread got locked out. o No: :eek2: Derek
My engines were built from 2010-2012, and Jim, Mike Phillips, and others were building 470 engines before that.
Derek, That is the basic reasoning behind the 470 combo, which I have been building since 2009. That particular page was created about 2 years ago. It's what I have been telling folks since 2009, via email and on the phone. I decided to write it out as it was easier to just point new potential customers to that page, than to have to write it over and over again. And yes Larry, the shortblock pictured is yours. There is absolutely no downside to a zero deck block, if you do it with the correct combination of parts. 20 years ago, one of my machinists looked at me and said "you have some really nice parts here, why on earth don't they fit the block without cutting .055 off it?" I started back then requesting the correct pin heights for pistons, unsuccessfully.. so I built my own, problem solved.:idea2: There is a brand new rod now coming out that rounds out that combo, building it into the most cost effective, mechanical efficient HP combo for the 455.:TU: I personally build 12-15 of them a year, and supply parts for about half that many to other Buick enthusiasts. It's been a very successful combo, my last piston order was 104 pieces.. and most of those are gone now. Since May... :shock: JW
Wish I knew about that link back then, I could of just posted the link to that to confirm the machining costs to someone that thinks those cost are as cheap as the India pistons he was recommending. :eek2: And like I wrote back then, people that buy the cheap pistons don't want to pay for the extra deck milling it takes to make the crap pistons run right. That would also cause a domino effect of $$ spending removing that much material, which is mentioned in the link Larry posted. I would recommend that it would be more worth getting different better pistons and getting your rotating assembly re-balanced than having that much material milled off of the deck! AutoTec offers a 4032 forged piston and ring kit that is customizable with no extra charge for your block's needs to get to a zero deck. If you need the better 2618 forged pistons then you may want to consider the TriShield Performance 470 pistons, but you'll need to get BBC rods and either have extra crank machining done past just having it stroked or having the BBC rods narrowed to fit the factory BBB crank throw. Maybe he offers a closer to stock taller piston for stock rods if that's what you want to keep? You could sell the pistons you have now to recover some of the $$. o No: Either way you decide to do the job, its going to cost around $1,000 to get it done. If you get the new pistons the block should be re-honed for the new rings the pistons will have, plus you'll need to have the rotating assembly rebalanced. If you get the deck milled it will be a double charge to remove that much material, then you'll need new pushrods, intake machined so it will fit right, and possibly have the pistons milled for valve clearance depending on what cam you're using. Something to consider as well with your Speed-Pro pistons is that they probably have a fully round dish with no quench pad on them so zero decking your block wouldn't benefit you as much as with a piston with a quench pad on them anyway. Here is an example of a quench pad on a piston; http://www.buyracingparts.com/pisto.../autotec-455-buick-forged-dished-pistons.html See how the dish isn't a complete circle, the flat area by the valve clearance, that is the quench pad. Without that extra flat area the quench effect goes out the window anyway with only a minimal quench effect with what's leftover that is a quench ring from the outer area flat on the dish pistons you have now. So really the only benefit you'll have is more compression if you zero the deck, which could make your engine more detonation prone depending on what cam you have now. GL Derek
Cool, I guess great minds do think alike :Brow:, wish I knew about that page before today, you know what I'm talking about.... :grin: In the bold, I totally agree with you there! But not really necessary with the cheap factory style complete circle dished pistons like the Speed-Pros, unless more compression is wanted. Oh yeah, almost forgot about the new 6.800" rods available for the BBB! The OP could get those and not have to get the extra crank or rod work done to make the combo work. That is stuff that is good to know when building a 455! Derek
Biggest worry on a BBB with a lot of deck clearance is detonation. 430's, with pistons .060 to .080 in the hole,(after a rebuild with off the shelf pistons), are most prone to this. I have experience fixing 9-1 430 motors, with 230* duration cams, that rattle so bad they sent them to me to fix them.. Done a couple of those now. The fix is mill the decks or replace the pistons. Both result in 10-1 motors that now don't detonate. JW
Yeah, a quench ring isn't as good as a quench pad, but it isn't nothing either as long as the compression doesn't go up to high with that type of piston. If the OP isn't having detonation problems now he may be better off leaving it the way it is unless he wants to upgrade to new pistons. The amount in the hole you mentioned is horrible! That should of never been assembled that way in the first place! Let me guess, they wanted to save on having the deck milled so they used the composite Fel-Pro Blue permatorque head gaskets to seal up the engine as well. Doing that left those pistons an extra .040" further down away from the head making them .100" to .120" in the hole!! Not recommended for sure! Its like the open chamber BBB heads vs the closed chamber BBB heads when a full circled dish piston is used the only difference is the compression ratio with both style heads having the same quench ring with a full circled dish piston. With a shallower dish on the mentioned pistons to bring up compression the open chamber heads would work just as good as the closed chamber heads. Now adding in a quench pad or a spherical dish the closed chamber heads would out shine the open chamber heads. Better pistons would be the way to go for sure. :TU: Derek
I personally prefer the balanced piston that a conical dish provides. I have noticed a reduction in skirt and cyl wall wear with the conical dish pistons. Having built a few motors with quench pad type pistons, I can't say that I ever saw any noticeable power difference. All those engines fell in the normal range of output, for a given build. 430 replacement pistons are built off the blueprint pre-production piston spec, which was for a 10.540 deck height. By the time the 430 went into production, the deck height had grown to the 455 spec of 10.570. Add the typical factory tolerance of aprox ..040 and you end up with pistons that are .070 to .080 in the hole. And then yes, a .040 head gasket makes it worst. JW
Conical or spherical like the pistons pictured in Larry's engine in the link is what I thought I was referring to in my prior post. o No: But yeah, Paul Muller(pmuller I think his alias is on v8? Where have you been Paul?) explained why that type of piston is better to me in one of the discussions a couple years back here on the board. I wanted to get that style for Andy's engine but the dish needed to be bigger on a sbb to get compression down for boost so we couldn't use that style. Anyway a MUCH different type of piston than a full circle dish type. I really didn't know the 430 engines were that bad, that's unfortunate, but it wouldn't be a Buick if there was good aftermarket support for these engines. Seems like ALL of the Buick engines are plagued with short compression distance off the shelf pistons!(the cheap ones anyway) Derek
