BritishV8 Forum

So let's see, a little math here and, voila! The 340 crank at 3.85" comes in at 97.79mm, but it has much larger mains. Of course those can be cut down, as can the bob weights, to make it fit the Rover block. I think it already fits the 300 block if the mains are cut down a bit. I have no idea what you could do with rod length in the Rover block, but let's say you went with a custom piston, made the ring package short and near the top, used teflon buttons and put them up into the oil ring and used a small diameter pin, you just might get a decent rod ratio.

Jim

Buick 215 deck height is 8.96", right? Half of the 350 stroke is 1.925". Half of a destroked 350 (taking 0.100") is 1.875". That leaves 7.085" for rod and piston. I'd pick a custom Honda rod with about 5.7" of length and that would leave 1.385" of deck height and allow for a reasonable ring setup.

The question would be, how far out of the bottom of the cylinder does this piston get pulled?

If crank/piston interference is too much, a longer rod might help that. That's a trade-off between piston rocking in the bore because of a too-short compression height, and piston rocking in the bottom of the bore because it got pull out too far.

Are the oil pans of the 215 and 300 similar? Clearing the oil pan was one of the issues with the stroked 300.

De-stroking should help with cam clearance.

That's a 289" engine, right?

The Westwood flanged liners are 5.34" long. SO the piston will be sticking out the bottom. With a destroked crank (3.75") there is only 1.6" left for the piston to be inside the bore. That means the pin will be pretty close to coming out too. YIKES! And a little cool.

Longer sleeves would help.

I do have to say that the 5.7" rod would work but the rod ratio is not very good. I think it's pretty close to 1.52 but an engine like this would not be meant for high powerbands. The only rod ratio I've seen that's worse is the Chevy small block 400. I think its like 1.48 or something. Putting the pin farther up the cylinder would help.

Isn't the SBC 400 using a 5.66" rod? That's a stroke of 3.75" too.

BTW, where were you able to find a 5.7" "Honda" rod?

The 'Honda' rods would have to be custom. I'll have to look again at the various rod maker's lists to see if that's even a possibility.

You are right about the longer sleeves. That must have been what Mickey Thompson did to make that 289 boat engine. I can picture longer sleeves that are profiled for clearance from the crankshaft.

Not a practical solution. Rats.

I'll redirect my attention to a more typical crank for stroking an engine. Sounds like the tried-and-true 300 crank is the deal. That, or just go with a 4.6 crank in my 4.0 block.

OK, I'll confess I don't understand the fascination with destroking anyway. I get it that the honda rod has smaller journals but I'd be inclined to go the other way with that and make the stroke longer, not shorter. Plus it can't help with crank strength to cut down the rod journals that much. But then again, I'd just go with the iron block. It's not that big of a weight penalty.

Jim

LOL. The only purpose would be to make it feasible for the Rover block. The answer is, yes, the iron block is probably the way to go but for the sake of fleshing out the complete concept it's worth it to go through the process.

I'm with you on the going the other way. That's why I liked the 360 idea:

Quote...use the "Honda" journal size to monster up the stroke to 3.96". Using the 6.2" "Honda" rod and the Ford "truck" 2.3 piston 20 over you'd get 3.8" bore x 3.96" stroke:

A 400 lb. 360cid (5.9l) Buick 300 with a very Chevy like 1.58 rod ratio.

I think that will be the next engine I build. That would be fuckin' sweet!! On the journal size. It's true that the crank strength would be changed but the Chevy guys are doing this all the time now. Probably with forged cranks. I hear the "ArmaSteel" cranks are pretty strong though. We'll see how it works out. I'm totally willing to take a risk. I think it will be fun.

Do you think we'd need a block girdle for the mains on the 360 idea?

Has it ocoured to anyone... "The further "out" we go- the tougher to return to Planet Earth"? Drag racers been using "deck plates" for stroke increases, to achieve a good rod ratio, long time. I feel  deck plates/adapters, may be best way for Lotus/Rover build. This would allow 3.85"+strokes with good rod ratio and no rod/cam bumping. roverman.

Well... if someone could figure out a way to keep a P76 block together....

Greg

Art - any idea as to when you're going to start your lotus/rover hybrid - that is VERY interesting?

Greg, It's called welding. Probably diminishing returns compared to much more readily available 4.0/4.6's. Tony, just because I can, does'nt mean I should. Kind of one-off project, if ALL went well, I could probably make 50c/hr. for my labor. Probably more sensible to design/build a better hemi head for the Rover. Much better overall potential. roverman.

Don't get pissy, Art. LOL. Seriously, is welding enough? I don't know the P76 block well. I know the Ford small small block needs lifter girdles from splitting in half. Then again that's with 800hp on vapors.

OR are you saying go ahead and break it then fix it with welding?

If you look at the ribs and such in a TA big block you'll have a better idea of what is needed. The lifter area is weak and will flex with a high lift cam. A girdle plate of even just 1/4" steel would help considerably with the bottom end. There is a lot of differing opinion on how that should be done and a thread on the V8Buick forum about it. Very likely the TA heads will breathe as well as the 4 valve heads and for less money. There isn't a bigger stroker crank than the 340/350 readily available at affordable prices and they will work with the cam in the block. Higher ratio rockers and/or a roller cam will get you the lift you want.

Jim

LOL!  Yeah Art, is it possible to weld alloy braces across the valley of a P76 block and have no resulting issues?  Enquiring minds want to know.

Greg

For the sake of notes on the 360 Buick stroker, here's the Ford "Truck" pistons:

http://www.kb-silvolite.com/spistons.php?action=details&S_id=435
http://cgi.ebay.com/ebaymotors/NEW-SILVOLITE-HYPEREUTECTIC-PISTONS-FORD-2300-4cyl-_W0QQitemZ290366397952QQcmdZViewItemQQimsxZ20091104?IMSfp=TL0911041910007r37886
http://www.summitracing.com/parts/UEM-3185H-5MM/

I'm pretty sure the "5mm" means .5mm (.0197) over.

Jim - some THOUGHTFUL comments on your part regarding T/A heads marketing strategy over on the V8Buick forum - why in the world would a company NOT do a cost/marketing analysis PRIOR to developing a new part!

Sir Art - I shall chip in .51/hr towards the design of that Rover HC/H (height-challenged hemi) Head - and because I'm such a big spender, please don't take your time.


Humm...dreaming out loud...get several of these related forums to come together for a Buick/Rover head design fundraiser - starting price point $1999 - they wouldn't collect dust!

.....and it looks like (a few V8 forum posts) there may be reason why RS hasn't provided any flow numbers for their heads - time and testing will tell.

Nic and  all. No, for using deck plates on 4.0/4.6 and getting piston where it belongs and good rod length for-say, 4 valve heads? roverman.

Nik-nixed, your getting my "underalls"-well-pissy. Wer'e one to measure lifter boss wall thickness on P76, they would find it's thicker than 215's, and comparable to sd-1's. I was yakin the "weldability" of BOPandR's.I  think welding "before" the block get's room-addition is "better"-Nic. Welding will probably slightly distort lifter bores,(they need bronze bushings anyway) and possibly cam tunnel, depending how "good" you are. Jim, all. Lotus heads with cams, towers and covers run about $100-$300 ea. I mite be off here, but I don't see the TA outflowin the 907 in a 3.7 bore, especially @ .45 lift. Unless the Lotus heads, kocks my sox-off, I see it as a one-timer. roverman.

I was reading about Cliff's stroker project again this evening and something else popped into my head. We were talking about offset grinding the 4.6 crank to get 3.4" stroke. Basically the 300 stroke with the native crank. Smart. I actually didn't think much about the journals in the late block being bigger in dia. till the other day when we were posting about it.

So then the thought occurs to me if the 6.0 "Honda" rod is used, 1.89" journal; The 4.6 crank could be offset ground to 3.525". Paired with the Ford 4.6 stroker 1.190" tall piston and that ends up with the piston only 7 thou below deck. Bitchin'! Just deck the block by 7 thou and that puts the piston at zero deck. Nice.

That would be a solid combo. Displacement with the 30 over Ford piston (3.73"): 5047cc. 308 cid. The 1.7 rod ratio is perfect.

That almost makes me waffle on building the lightweight Buick 360 cid. idea.

Yeah, I like the idea that a 4.6 crank can be used without a custom flywheel. I've got a complete 4.0 engine and I wrestle with the idea of stroking it with an offset ground 4.6 crank.

You just made it worse.

I found a website of a boneyard that sells Rover parts, including cranks. $300 for any 3.5, 3.9, 4.0, 4.2, 4.6 crank. Stroking gets the biggest return for the expense.

OK you "strokers", I'm thinkin the bottom corners of rods are bangin the cam? How bout VW "style" with stud in cap and nut, or cap screw on top? Leaves more room in there. "Slim chance better than no chance", roverman.

Use the late capscrew style 350 rods if you can.

Jim

You're saying that the heads on the rod bolts are hitting for the 3.95" stroke, right?

With that stroke it will be hitting the block in several places or is there a lot more clearance in the 350 block I think you must be talking about, with all the different combos we;ve discussed am getting confused.

Kevin.

I'll defer to Jim there. My assumption would be it's very similar to the 350/340 block on the very bottom. Well, for the sake of feasibility, That stroke will pull the pistons right out the bottom of the sleeves. So, no go, either way... Well I guess unless you get longer sleeves. It's gonna be tight!!