A sweet sbb 350 combos if anyone is thinking of building one.

King bearings have rod bearing spacers for 2.100 Chevy rods to use in Ls engine with 2.00 rod journal. Should work in SBB engines also. Just in case anyone has ideas.

 

I won't fall for your bait, Derek. lol


Gary

 

That wouldn't help with cam clearance though, the sbc rods with the 2.225" housing bore is wider than a sbb with its 2.125" housing bore. That's like .050" per side that they are probably wider.

Although, there are a few short bolt stroker rod styles that are made that could possibly clear the cam? This warrants further investigation, can you post a part number or summit link for these Andy? Thanks.



Derek

 

I wasn't trying to bait you. The disappointing stock type build is an un-blueprinted build which has nothing to do with the kind of build that you want to do. The guys that buy the 10:1 pistons and buy a big cam but don't have the deck machined so they only have 8.6:1 and are disappointed on how it runs. Your blueprint build would run sweet with the stock parts and even sweeter with the nascar take out rods that are 150 to 190 grams lighter than the factory cap screw rods.


I seen that other post by the way. LOL


Derek

 

haha. I figured you did. I left it up long enough so you could see it, then removed it so I wouldn't clutter up your thread too badly.

 

Thanks. LOL

Wasn't trying to bait you just so you know I like the blueprint idea if that's what you want to do. If in you wanted to cheat a bit though those $2,000 rods would be a sweet addition for under $200!




Derek

 

http://i.ebayimg.com/00/s/ODg4WDgwMA==/z/YLMAAOxyOMdS3XVk/$_1.JPG
Bearing spacers

 

Yeah I think it's a great idea. Would add to the power and durability of the engine for sure. I'm never opposed to adding more power, just not at the cost of engine life.

I was just kidding around with the baiting thing. I can't be all serious and no play or I'll be as boring as those stock engines I endorse. :laugh:


Gary

 

The rods wouldn't make the engine make more power, they would free up some of the power that would already be there though which is more important in a combination than forcing it to make more power with a cam profile sometimes. Skinny rings help free up a lot of power as well among other top secret things that don't sacrifice durability.


Derek

 

Yes indeed. Notice I said it would add to the power. I didn't specify, but you're right, it does so by freeing up power already there. This is the whole point behind blueprinting in general. Making that rotating assembly turn easier is one of the main goals.

The 'top secret' tricks are actually common sense (or should be anyway). Anything you can do to make that crank turn easier will add (free up) power. I learned this many years ago from a Chevy builder in Atlanta, GA when I was in my early 20's. He was a smart man, though he used to scoff at Buick engines, believing them to be inferior (power wise and cost wise). This was before many aftermarket parts were available for them. There was much wisdom to glean from him though, and shared with me some very interesting techniques that can be used with ANY engine. I just took this knowledge and applied it to Buicks, along with my own knowledge and experience.

The Buick community was all but non-existent then, or at least that I knew of, though I've always loved Buicks from an early age. Then comes the internet and this website, and I was blown away with how many people there are out there who share the same enthusiasm as me. There's some rotten apples here and there, but you can't let that discourage you. Who knows, they may even come around and become better people once they see that being nice isn't a weakness.

Not sure if those rods are something I would want personally, but it is a good idea for anyone interested. In short, I approve of this message.


Gary

 

Hey Derek,
I bought the second rod option, so throwing my hat in the ring to build a boost monster.
I take it I can use the Autotec forged Pistons with these. Could you please write up exactly what is needed to make this work, so I can print it off & provide the machine shop with detailed instructions. FYI, I have a Mark Burton twin turbo set up.
Thanks James

 

Although the AutoTec pistons are really nice pistons they aren't necessarily the best choice for a boost build. The AutoTec pistons are made from 4032 forged alloy that is great for tighter pistons to wall clearance than the 2618 alloy and will handle higher than stock compression ratios and RPM but aren't the best if you want to run a lot of boost, they will handle around 5 PSI though up to 600 HP although some have pushed that limit as far as 800 HP it isn't really recommended.

For an all out boost build you will want a piston that is made of the forged 2618 alloy, a far superior piston alloy to handle the extreme cylinder pressures of excessive nitrous high compression race type engines and also high boost type engines.

Seeing how aftermarket piston choices are limited for the sbb 350 a "boost monster" engine would be better of with a custom piston. I think Andy's Ross custom pistons were about $800 counting the cost of pins, the rings for a boost engine that he got were around $200 to handle the boost reliably. The top ring is steal not cast iron, not sure but the second set might be steal as well with the top ring being chrome molly faced.(not to be confused with a molly faced ring, chrome molly is a much harder material that takes longer to break in than soft molly)

Going with a custom piston you can have them made any way you need them. Your best bet would be to have the block sonic tested to see what kind of overbore it can handle, a 3.905" and a .090"(crank grinder will need the .010" to be able to index the crank) extra stroke would be a 377 sbb. Even if you don't go with the .105" overbore you'll need to choose an overbore that good performance rings are made for.

So I am guessing that you bought the 6.370" rods with the pressure fed .787" wristpins? If so you'll need to have the rod journals on the crank ground down to 1.889". You can either have the crank ground with an additional .090" stroke or you can leave the stroke where it is but still need to have the rod journals machined to 1.889". I say go for the extra stroke if the rod journals need to be smaller anyway.

Computer is starting to lock up so I'll edit this later post it now so I don't loose it!

Derek

 

Go with diamond pistons if you can.

 

How much are diamond Pistons going to set me back Sean? You don't happen to have an xtra set that you want to unload??

 

6.370 rods, yep, those are the ones I bought. Just guide me & the machine shop in the right direction......

 

Get a price for pistons from Scott Brown. Mine where around 650 and ended up being from Ross. .827 pins where around 200 . I'm sure you can hone rods to that size pin safely if you have to but he can make them to your spec. Also has piston coatings available.

 

No spares, I think it was about 800 for the pistons rings and wrist pins but they are really nice. They already have the valve reliefs programed into the computer and they can do them in any deck height to give you zero deck and whatever dish you want to get your compression where you want it.

 

No problem, a few questions first;

What stroke do you want to go with? The stock stroke is 3.850" and if you have a virgin crank you can go to a 3.940" stroke when the rod journals are taken to 1.889", .090" extra stroke and .010" so they can have material to index the crank.

You'll need to have your machine shop measure what the deck height is after a cleanup square cut, if they have the capability to cut the deck square to the mains?

If you want the engine to be an internal balanced you would be better off starting with a '74 and newer crank because there is less drilled out of the throws on those because the newer style cap screw rods weighed more. Not really necessary to internal balance the crank but IMO it would run smoother in the higher RPM band those light ass 500 gram rods would like to be!

You will need to have one of the head chambers measured to see what CC they are so you can order your custom pistons with the right dish volume to get the compression ratio you're trying to get. I think for a turbo engine that 8.6:1 to 9.2:1 would be a good ratio to shoot for depending on how much boost you're going to throw at it.

The Scott Brown head gaskets are good for 20 PSI of boost so more than that you probably would need a custom head gasket of some sort. I think 20 PSI would be WAY more than your car is setup for! LOL Unless your car is setup to run 8s in the QM? If you don't plan on racing then that won't matter.

Remember just building a strong running engine that it WILL find the weak links in the drive train. It will be hard to get a TH350 to handle more than 550 HP, that's about the range they don't like to go over or they won't be as reliable even if built to handle more.(ask me how I know) You'll probably want to run a TH400 I think in stock form they'll handle 600 HP, you'll still need to have one built to handle a bit more than that though.

Then there is your driveshaft that will need upgrading with replacing it all together would be the best way to handle that but at least get heavy duty U-joints and yoke.

Make sure the rear is up to the task of handling the power as well, not only the internals of the rear end needs to be addressed, the suspension parts need to be upgraded as well. Especially making sure the frame mounts of the rear are tied together with at least the factory big block car rear control arm frame mount braces you'll need them along with at least boxed in stock control arms but after market would be much better.

And don't forget about brakes, those will need to be upgraded to handle the intended power gains as well.


So just to recap;

What stroke do you want?

What is the CCs of the heads?

What is the deck height of the block after square deck machined from the mains?

How much boost do you plan on running?

What head gaskets do you plan on using?

Knowing the above will better help me help you.




Derek

 

I like the stroke u described.
They are 71 heads, no idea cc.
Block deck, guess after marching we will know.
Running 8 lbs on stock 71 block, plan to run 15- 20 lbs.
Head gaskets, whatever will hold the boost.
Not sure how helpful this was......

 

That's a start anyway. Well if no one that owned the engine before you took Andy's advise and "shaved" the heads .050" to .070"(LOL, JK Andy) then they should be close to 59cc I think the factory CC is supposed to be. You will want a minimum cleanup cut on them which could be .005" to .010" which can take the CCs down to around 57cc maybe, to know for sure they will need to be measured.

Hopefully your machine shop has the capability to square cut the deck to the mains and able to measure the deck height afterwards. Ask them if they have those capabilities.

These head gaskets are suppose to handle as much as 20 PSI;

http://www.buyracingparts.com/gaskets/buick-350-severe-duty-head-gaskets.html


So maybe this will help you figure out how to determine what compression distance you will need for your pistons;

We know the "blueprint" deck height dimension for a sbb 350 is 10.188" and typically the older blocks are around .030" taller than that dimension whereas the newer later blocks had around .060" more material than the "blueprint" dimension.

When factoring in the stroke to get the compression distance of the piston, the stroke needs to be divided by 2 so half of the stroke. That is because the offset of the rod journal is half of what the stroke is that revolves around the main journal, starting at BDC and ending at TDC equals a full stroke.

When you stack the compression distance on top of the rod length on top of half the stroke you have the piston at top dead center(TDC).

So now we take what the actual deck height measures, the length of the rod and half of the stroke and we should get the top of the piston to meet at the top of the deck, here is an example;

10.188"(deck height) - 6.370"(rod length) - 1.970"(half of the 3.940" stroke) = 1.848" would be your compression distance to get the piston level with the deck's surface.


To figure out what CC you need in the dish of the piston after you know what the head CCs are you can use a compression calculator like this one;

http://www.wallaceracing.com/cr_test2.php

The head gaskets I posted a link to come in 2 bore sizes, 3.840" and 3.905" with both of them having a compressed thickness of .050". The 2 different bore sizes will give you some leeway to tweak your compression ratio if need be by choosing the smaller dia. gasket will give you more compression while the larger bore dia. gasket will help lower compression slightly. Also if you choose to use these gaskets being that they have a .050" compressed thickness to get a .045" quench ring the pistons need to be .005" above the deck's surface so when you do the stack up math you'll need to add .005" to the compression distance of the piston;

1.848" + .005" = 1.853" is what your compression distance you need to order you piston at if the block measures at 10.188" after a minimum cleanup.(will more than likely be taller than that by at least .020" with a minimum cleanup)

Just let me know if you have anymore questions, I'm happy to help if I can.

A little background on the rods you have, the nascar engines are 358 CID with around 830 HP @ around 9,000 RPM that they spin them to. With your engine your RPM will be much lower probably peaking around 7,000 RPM with torque being much higher than the nascar engine. So if a stock rod can handle 700 HP with a Burton turbo kit those rods should be good to 1,000+ HP?!!

I noticed that one of Greatscat's sbb 350 girdles sold on eBay, was that you that bought it? If so you better have a built TH400 or something stronger behind that thing you're building! LOL(I love it!!)




Derek