A totally hypothetical 292 Chevy 6 question - I don't know if this would be do-able and if it was, it wouldn't be cheap, but I'm wondering if it *could* be possible to bore the cylinder walls almost completely out of a 292 Chevy 6 and then install sleeves to allow for a 4 inch bore? Does anybody know? Has anybody ever tried something this? If it it's do-able, I'm thinking that you could end up with one heck of a really "big 6"! Mart3406 ================================
I happened to have the stock B & S specs for a 292 here on my desk. Imagine that! I don't see how that is feasible........the stock bore is 3.875 (3 7/8") so, a 4" bore would be .125" greater than stock. Assuming the engines are thinwall castings, and I think they are, if boring it .125" over is too much for the casting, or is at least marginal at best........how would there be any block material remaining to support a sleeve that has a 4" bore? Seems to me boring big enough to accomodate a sleeve who's INSIDE diameter is 4" would probably eliminate the cylinder walls entirely. And, according to my notes, with a stock stroke, that would yield 310 cu in......on 18 greater than stock. However, .060 over, which I believe the blocks will tolerate, gives 300.6 (just for fun, call it 302) and though it's not a GREAT increase in displacement, it is SAFE, and every little bit helps. Just my thoughts............yours may differ Ray
---------------------- Thanks. That was the kind of info I was looking for.....and kind of what I expected too. : Oh well, back to the drawing board! Mart3406 ===============================
Well, my comments were just answering your question.......not intended to discourage you from building a 292 Chev 6. I think they are cool engines with lots of potential (of course, that is no news flash) and have terrific torque.......which is what moves cars..... I have three "core" 292's and have some interest in building one, though not a front burner project at the moment. My dilema is this.......I just love the "romance" of a older GMC 302 (I have a complete 270 and access to a 302 block/crank) but that is an emotional notion. My reason tells me the 292 is a considerably better engine to work with. It has 7 main bearings vs 4, is lighter in weight, parts are readily available, etc, etc.. But dammit, it just doesn't LOOK quite as cool as the older GMC's............ Ray
Well, I suppose you could fill the block with Hard-Blok if you went out .125...but then of course forget about street use. I would guess that for the price of punching things out .125, you could probably build a mild blower setup (or build a really trick hybrid head out of V8 heads) that would make more power than "just" having a 310 I6. Fwiw, I've got a 292 in my car (stocks internals with an Offy intake and Stovebolt headers)...and it's a ton of fun.
But the Ford has a "mere" 4" stroke............the Chev 292 is 4.120"...... MUCH more torque and .060 over yields more than 300 cu in... Ray
It is possible to bore a 292 to 4", you need to have the block sonic tested to make sure it doesn't have too much core shift. You can tell a lot about it by looking at the front cylinder location by looking behind the water pump location and check the width of the machine work (width of the cut to allow the pump to fit without hitting the block) It should be about 3/8" wide. My cousin has a 311 cu. in. 6 that is a 250 block with a 292 crank, 400 rods and 350 std flat top pistons. He had to cut 1" off of the counterweights to keep them from hitting the wrist pin bosses on the pistons. It's pretty radical, has a Self lump port head and a ATI super dampner, 3 x 2's, that we fabricated a manifold for (it needs to be heated) and tube headers. I don't remember the duration and lift on the cam , but it is radical and we had it on a run cell and broke in the cam. It's in my pictures on this site. I have a .030 over 292 that's on you tube under good six just after we broke in the cam on it. I'm starting a build on a 37' Ford pu with it and a richmond 5 speed.
I would only bore your block enough to clean it up, as any more than that will only weaken it and you won't be able to rebuild it any. The head, cam choice, having it balanced, and a good manifold will make you some serious horsepower. Glen Self kicked ass for many years with one in a 68' Camaro. He uses ATI Super Dampners (for a 350) with a #88 Durometer rubber, mine cost $406, but you gotta have it to keep them together. My cam is a 231 duration at .050 with ....565 lift, range is up to 6800 rpm.
I used to race a 300 ford 6 in a 51 Anglia. With modern thin wall castings stay as small as possable in the overbore. Bigger will only get you cylinder flex and poor ring sealing plus possable cracks down the road. .030 is about all you want to go safely. The motors are near indistructable but vibration is a big probem keeping flywheels on, thus the modern balancers which werent available when I ran mine
I machined my 292 .080 over. had no problems with it for years on street driving it would run a bit warm in the summer but pretty sure that was more from not running a shroud than the displacement. good luck
Wet sleeve engines are nothing new. It would require some careful planning, but could be done. That said, it would probably be cheaper to machine your own 4" block.
If they could build 460 cubes out of a 283, and i have a magizine that they did that, then they probably atleast attempted that, magic can be achived in a filled and sleeved block
I have a 292 that I did just that, bored out the cylinders completely from 3.750" and sleeved for a 4" bore (1/8" wall sleeves). I did fill the block to stiffen the deck and am just cooling the heads as it will only be running 440 yards.
I just checked a 292 block in the shop and I think if you sonic test and find that you have a minimum .200" cylinder wall you could bore .125" over and still have a little more than 1/8" wall, which is good enough although a little thin. The next problem would be what piston to run. 292s have a comp. height of 1.936" and 2.009" and a 350 has a comp. height of 1.54", 327 gets a little closer but not close enough. You can have some made but they will be pricey. Now let's look at the 300 Ford. Comp. height is 1.740" with a .975 pin. 390 Ford (flat top 4 bbl pistons) has a comp. height of 1.748" and a pin of .975 also. So with a 4.110 bore (.060 390) in the 300 you can use 390 pistons off the shelf and have 318 cubic inches. Something to ponder.
When you wet sleeve these blocks you need to think about what happens to the deck when you torq. the head down. From experience, it becomes like JELLO if decked very much.
Nobody has yet pointed out that adding cubic inches to an engine that is already severely restricted in the head department will not yield any performance gains. Your money is better spent trying to optimize the head flow capabilities.
That's true, but in wet sleeve engines both block and liners are designed for that application from the beginning. The liners are generally very thick with o-rings to seal them to the upper and lower spigots in the block. Boring the walls out of a non liner engine and trying to wet sleeve it would be another animal altogether. I'd have to say that doing this to a 292 likely wouldn't be a success. Bob
BAck in the day wheni worked at Wilsons we bored the shop dragster 300 Ford to take 428 Cobra jet pistons. First attempt was a failure(Ran good till the first burnout) but with thick wall sleeves second worked well. A lot depnds on the machinist doing the job. Does he use a step in the bottom of the bore to positively locate the sleeve. Some guys do some dont. With the step the sleeve is going nowhere. A half pour or short pour BTW will had strength to a block and it will still run cool enough. Why? because there is no fire at the bottom of the hole as the piston takes up have the length even at the bottom of the stroke. We often pour just to the bottom of the water pump hole. If you are a machinist and have your own bar or access to one and you dont have to spend any gold to try something like this that is a whole lot different than trying to get someone to do it and pay knowing it may or may not work. There are half a dozen options here that would make it work but really like mentioned how much are you going to gain from the extra 6 or so cubes. 6 hp maybe? Is all this extra risk and trouble worth it. No one ever won a race they could not finish. BTW dont sell the funny looking head short. i have had one on the flow bench un modified and modified. With floor plates the flow would shock you. As good as the Dart 300 HP replacements for the SBC. Sometimes because something looks funny we think it is no good. Not always true. The head I just spoke of is still on the "Fouramerica" vintage 35 Chev stockcar. It has been touring the Florida vintage circuit for a few years. We first did it in 2001. Don
Hmmm?? Very interesting (and also, encouraging) insight re the flow-potential of the head! Mart3406 ===================================
I see you are a fellow Canuck. The Fouramerica Stock car was built here in Canada by Dave Mckeown of Belleville. It was orginally called FourCt which meant For Camp Trilliam as it was used to raise funds for the Childrens cancer camp near here. It wa sthen sold to someone in Baltimore MD and eventually wound up in Detriot where it was raced for a few years and on display in a museum. Rich Iverson has owned it twice and just recently sold it to someone in the Daytona area. I remember very well all the testing and such we did. I designed the combo, picked the cam and had it made and did all the machine work. Dave Mckewon assembled the motor. I tested the head on the bench several times as we worked on it. Once the floor plates were installed and the intake port boss removed (a countersunk screw replaces the headbolt and the access holes for them are plugged with a pipe plug which is installed then flush ground inside.) When the port floor is raised even 1/4 inch flow comes up immediately. The heads work despite their strange design because they have hi port volumes being siamesed and all. If you study an engineering books on fluid dynamics you findthe when a fluid and air is a fluid is forced to make a trun if it is done from a large chamber the flow loss is minimal compared to trying to get it to turn in a pipe or small port. That is the saving grace of these heads. At least that is my undestanding of why these funny looking heads can be made to flow so well. Don
---------------------- That's great information, particularly on the the head mods! To be honest, I've never heard of the FourCt/FourAmerica car befere. Do you have any pics and particularly more information on the engine combo? I've been doing some more thinking and reading up on 292s and I'm thinking now that with the relatively long 4 1/8 stroke, that this engine might respond well to turbocharging.and building around a 5000- 5500 rpm peak, rather than trying to maximize displacement and/or make a high-rpm screamer out of it Does Anybody here have thoughts, info or particularrly, any first hand experience on this? A few years I helped a buddy engineeer and build a efi-turbo'd 2.3 Pinto engine that eventually dyno'd at 442 hp at 5500 rpm on 24 Ilbs boost. We used a homebrew EFI using a mega-squirt controler, and a hybrid Turbonetics T3/T4 - .60 A/R turbo. I'm thinking that since the 292 Chevy is just slighty over twice the displacement of a 2.3 Pinto, that a similar set-up, but using two of these same turbos might work out well. The Pinto used an Eslinger aluminum head but that was probably a bit of overkill, considering the self-imposed 5500 rpm limit we used. Most of the power I'm sure, came from 24 lbs of boost which similarly should also overcome any flow deficencies in a moderately modified 292 head - and keeping the maximum rpm in the 5000-5500 rpm range would seem to be ideal for an engine with 4 1/8 inch stroke. Plus, the 292 has a bigger bore than than a Pinto, and also 5 cylinder head bolts per cylinder rather than 4 on the Pinto, which should help contain high boost pressures better. Packaging a pair of turbos plus the plumbing for an intercooler on a 292 with both the intake and exhaust ports on the same side and then fitting it into all a car might be a bit challenging, but If we made made 440-plus hp from a lowly 2.3 Pinto, 4-banger I don't think it wouldn't too dificult to make upwards of 750-800 hp from a similar combo on a 292 inlinr 6! Mart3406 ========================================
292 is 4 bolts per cylinder like the 2.3. The deck thickness is the limit here, typically 14-16psi is the practical limit.
mart, I daresay that if you're going into near-4-digit horsepower requirements, you should talk with Leo Santucci. He's got a hybrid-head (as in made from two SBC heads), big turbo'd prupose built 292 stuffed into a '54 Studebaker drag car. Something approaching 1350HP IIRC. Forced induction will over come a 3.875" bore for power much better than punching skinny cylinder walls to 4.00"
FourCT car or FourAmerica vintage stock car. Sorry i was so long replying. here are some pictures and a bit of the story on my website. The page has shifted and I will have to fix it when i get back from my trip but the info is there. http://seniordragster.bravehost.com/4ct.html Richy Iverson has owned this car twice but recently sold it to someone around Daytona. It was runnerup in the New York State Vintage Stockcar Association in it first year of racing and did well thereafter. It went to Baltimore then to Michigan, then Indy but spent the last few years in Florida. Don
I used to race NHRA stockers and I can tell you anything you gain in cubic inches, you lose in cylinder wall stability & ring seal with too big of an overbore. I also ran a Ford 310 inch {.060 over} 51 Anglia in the 70s so I know a little about 6's although its 30 year old technology
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