Engine and Transmission Tech

Oh @#$%&. Ok. How did I get to 1.12?? I must have been really tired. I had been working for about 35 hrs. straight when I started this thread. I was board waiting for a render from our "farm" (processor array for processing movie frames). I was working on a rush job. I think you posted this a couple times. WOW it really didn't get through. LOL!. Thanks for goin' easy on me, Kevin.

I went back to find where I had decided the height was different. It was after a long time awake. LOL!. OK so scratch that last post about using the "Honda" 5.97" rod. with the magical 1.12" Ford pistons. Unicorns.

The best part was that I'd already done the math a dozen times.

Some food for thought, based on the 340 build.

OK, now here are the Venolia pistons:



And here are the stock aftermarket replacement pistons:



If you look at the pin placement, the Venolia has a 1.283" compression height and there isn't a whole lot of room below the oil ring. Bear in mind this piston uses thinner rings and this is also .750 wrist pin. On the other hand, these are blower pistons. The ring package could be moved up on a N/A engine. Also, the oil ring can extend into the wrist pin area if teflon buttons are used as they were with this build. In that case the buttons have a groove cut to match the oil ring groove. Also these were used with 7" rods to get a zero deck. (actually .005-.008" above the deck depending on piston rock)

Both engines had very similar compression 10-1/4 stock I believe vs 10.6 with the new rods and pistons.

Jim

They sure had a lot of metal on those old pistons... Those Venolia pistons are custom, right?

Yeah, totally. They quoted $75 each but by the time we added pins, buttons, etc,etc,etc it was over $1100 for the set. I think you could do just as well with Diamond and at a lower price.

Jim

Guys,

Just for information, the longest stroke crank for the rover block produced by John Eales (JE Developments) is 91.5mm/3.602" for a capacity of 5298cc with 96mm./3.779.5" top hat liners. Not cheap though!

Kevin.

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?



Edited 1 time(s). Last edit at 11/04/2009 01:28PM by pcmenten.

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:

[www.kb-silvolite.com]
[cgi.ebay.com]
[www.summitracing.com]

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