Yeah! Depending on the grade of E85 you use, you could push it as far as 15:1 SCR... The combination I suggested above is good for about 440 ft. lbs. with long, small tube headers, I bet you could get it closer to 500 ft. lbs. with all that done to it. lol
The 'like' feature makes this easier to communicate, saving excessive quoting and narrative as well as a positive backstory to ensure fragile egos aren't bruised....and at the end of the day you can tell if the OP liked it or was influenced by the occasional naysayer and ensuing bandwagon trainwreck. There should have been a sarcasm font adapted universal to the entire internet.
lol I wholeheartedly agree. Should be more humor emoji's or whatever they're called nowadays. Better to derail with fun and humor than bickering and pouting.
Cool discussion... My good engine features 9:1 compression with zero deck pistons and a large dish. Valve reliefs so any cam can be used. The new TA heads will be used and they are a closed chamber design so we will have a 40 thou quench distance so it should work well. I expect good HP and TQ without boost and more with turbo boost...
While we're at it, why not add in a topic about overbores, and how much is too much, if there is such a thing? Are all Buick 350 blocks thick enough to accommodate the .060 overbore, or is it safe to do a sonic test before going that far? I know the deck height on the later blocks (like '75 and up) tend to have more deck height, around .020 or .030 above 'book value', along with the heads being a bit thicker as well, would logic hold up to the assumption that the cylinder walls have more material as well? This could also add to the variances in engine weight, as some say it's only 450 lbs., while others say theirs weighed more.
A lot of technical data here, and opinions very greatly. But as far as deck height there are pretty much the same. They lowered the piston height so it shares the v6 Pistons. Spec on early Pistons is 1.835 compression height. Later is 1.805. There's the .030 difference. As far as overbore it seems they are good for .060 easily. As sonic tests by Derek and johnny already running.075 over. So it's fairly safe to say but sonic test should be done if your pushing the limits.
How about a topic on what you have to do to get around those obstacles or how many cores you might have to go through to find ones with acceptable risks given the application?
There seems to be some confusion about deck height differences. There's .030 difference between those piston types, yes, but there's also a discrepancy on the deck height itself. The book value says it's 10.187". This would put a piston with 1.805 CH at .072" below deck ('throw' distance (stroke (3.85) divided by two) plus rod length of 6.385, plus 1.805 (comes to 10.115), subtracted from 10.187 = .072). Everyone who's measured varying blocks say they get anywhere from .090 something to well over .105 below deck. This means the book value is off by .020 to .030 something. Use those 340p30 pistons which have a CH of 1.835 and it would sit at .042 below deck, but others say they sit around .055-.058ish on older blocks. That's still .013-.016 off book value on those. If they're all the same, then why are the numbers all over the place? Not trying to be a smartass here, but trying to get the information sorted out so there's no confusion. This has been discussed at some length a few times a long time ago, and I thought we all pretty much came to the conclusion that there was extra deck height over book value on most if not all blocks, more so on the 75+ blocks. Maybe I'm the one who's confused here? If so, I'd like to get the information straight so I can adjust my mental files.
Wow, didn't realize this created a storm of new questions and great input.... Since I am just "dangerous enough" to pull the engine, heads and know what a cam is I ...... getting back to my original thought.... This what I am doing similar to the guy above with the Crower Cam and please note this is a driver that I take to cruise night or with the kids to get ice cream..... My original engine post http://www.v8buick.com/index.php?th...need-a-little-more.320198/page-2#post-2698302 new pistons (you are verifying these v6 pistons will work) Crower Level 3 cam, springs and lifters TA Performance Timing set TA grooved cam bearings TA Main bearings 5/8 oil pickup Maybe 60 psi oil relief and folks are recommending I have the oil passage drilled... Power timing TA 350 headers 2.5 dual exhaust with H pipe Should I advance the Cam 4 degrees with this set up? Should I definitely have the oil passage drilled with these pistons? Thanks again all!
Opinions differ on those subjects also. But I would drill passage and go 4 retarded or zero on the cam with the flat top Pistons as static compression is already 9.8 . Most of the guys advancing the cam have much lower compression. I would suggest a 2200 converter also.
I have had many blocks mesured by the machine shop and all of them have been taller than the 10.18 factory spec. We have seen them range from 10.19 to 10.24". Regarding the max overbore it is advisable to sonic test before boring anything over 30 thou... Some blocks will go with larger overbore and others will not. Personally I like to bore 30 over and keep more material in the walls.
Thanks Sean. Mental files updated. So .010 all the way up to .060 over book value isn't unusual on deck height. Standard, .020, or .030 overbores are generally considered pretty safe, while .040 and .060+ overbores should be sonic tested for piece of mind. Personally, it would bug me not to do at least a block and head true up to take out core shift/block/head warp, since every engine I've ever heard of (not just Buicks) have all had no two piston sitting at the same distance below deck, moreso from one side to the other. (((In an engineering document printed back in 1967 on the (then) new Buick 430 engine being tested, one of the key things that stick in my mind was how far off each cylinder compression was in relation to each other, varying by .38:1 compression (over 1/3 of a point) from the lowest to the highest))) This should remove about .005-.020 from the heads and block (each), give or take. There should be plenty of material to work with, and from what I've been recently told, up to .030 is all the same price on machine work.
Like Andy said, 4* retard on the Crower cam, which would technically be 0*/0*, or straight up, since 4* is said to be 'built into' the cam. What this means is if you line the dots up on the timing gears, the cam will sit at 4* advance by default (some say Crower cams are off by about 1* in reality, which is actually very good considering many aftermarket cams can be off by a few degrees), which is why it is imperative to degree the cam, ignoring the setting on the timing gears. The Crower level 3 cam is supposed to sit at 66* intake closing when set at 'default' (4* advance), so sitting it at 70* would indicate a 4* retarded position. The FM cs647 cam sits at 71* intake closing, so you'll be close to that with a 4* retard setting. Ultimately, you'll want to find out where your compression ends up at before deciding on where to install the cam, and install it to get a safety margin on detonation, wherever that ends up being. If compression with those flat tops ends up being somewhere between 9.75-10:1 static, the 4* retard setting (70* IVC) should put you in a good place on the Crower level 3 cam.
So far everyone I know that's has degreed the crower cam has found no built in advance. So degree cam to confirm.
I'm just going by Crower's claims, and the cam card they have listed on that cam on their website. But yeah, degree it for sure.
Hi guys, my engine builder is asking if we took .020 off the heads and these v6 pistons don't have any valve release....are there any issues and does he have to cut valve releases in the pistons? He said he would have to partially assemble the engine to properly measure. Thanks for your help!
Using the flattop v6 3.0 Pistons? They sit .090 below deck . .020 off block puts them at .070 and the .043 felpro gasket would still give more then enough valve clearance. With the 10 plus compression I would set cam at 116 center, 4 retarded. Cam list built in advance but have seen it to not be built in.
Yes, v6 flat top pitons. We took the .020 off the heads (not the block) so I assume the end result will be the same. Great, thanks... you and this forum have been a great help on this build..... hope to get it back this week.
I would spend some time enlarging the chambers with a die grinder long before retarding a cam if I was concerned about possibly pushing the engine into detonation. Next I would consider a different cam. There's so many other ways to keep detonation problems at bay, that I can't consider retarding the cam to be a good way to handle the issue.
It's not about detontation as much as following a known combination. But yes the dynamic compression is getting high there.
