pics: cam-clearanced stroker rods

[Jack]

As I began to assemble a small block stroker I couldn't find pics that represented how the connecting rods should be ground (cam-clearanced) ... necessary to prevent rod-to-cam interference. So, after I did mine I shot some pics. I'm using the rods in a 3.800" stroke sbc with a MILD cam similar to an L-82 profile (installed straight up). If and How you modify your stroker's rods will depend on your cam, your rods, your crank; I offer this as simply a guide. I ground them using both a carbide burr & stone in a 1/4" air-driven die grinder. These posts are my first attempt at posting pics on the net ... lemme know if you have problems accessing them.

Please find attached 3 pics of GM "pink" 5.7" long connecting rods for sbc that have been cam-clearanced on side facing cam. Pics show side-by-side comparison to UN-ground side that faces oil pan rail. P1 shows ground side on bottom rod, P2 & P3 shows ground side(s) on left rod(s).

http://www.imagestation.com/picture/sraid20/p95fb733a02251f858d80be84b61b2390/fdbd8628.jpg.orig.jpg

http://www.imagestation.com/picture/sraid20/peec0cdcd3b2d883aa568ef490aa6768d/fdbd861b.jpg.orig.jpg

http://www.imagestation.com/picture/sraid20/peec0cdcd3b2d883aa568ef490aa6768d/fdbd861b.jpg.orig.jpg

JACK:gap

 

[Ken]

These posts are my first attempt at posting pics on the net ... lemme know if you have problems accessing them.

Try again Jack.

 

[Tom Bryant]

Imagestation

Jack,

I just started using Imagestation so I don't know all about it but my pictures are in an alblum. Anybody can access the alblum and view them if that's the option I select. Here is what the coding looks like.

http://www.imagestation.com/album/?id=4291863091


I don't think I can access the single pics unless thay are in an alblum. Like I said I'm just starting to use Imagestation so I could be wrong.

Tom

 

[Yoda]

Photo script testing..

Testing from imagestation website

Jack... go to your imagestation website and open the photo you want to reproduce here... RIGHT click on the photo, click on properties then copy the url path (script) then add it to your post here with the proper img's. Please reference Photo Help for proper size and more indepth help

BudD

 

[Jack]

SORRY FOLKS! ... I'm trying...

I successfully tested the initial pics (even using different email addy) ... but maybe SONY/infostation recognizes my 'puter ... I dunno? Anyway, I made another album (made sure there were no restrictions to viewers) and reposted the same pics in same order ... 'cept link 4 should be pic of my vette & link 5 should go direct to album. Take a look & lemme know if it works now.

http://www.imagestation.com/picture/sraid20/p95fb733a02251f858d80be84b61b2390/fdbd8628.jpg

http://www.imagestation.com/picture/sraid20/p1e0e85e866352487f8d417d257fb9975/fdbd8621.jpg

http://www.imagestation.com/picture/sraid20/peec0cdcd3b2d883aa568ef490aa6768d/fdbd861b.jpg

http://www.imagestation.com/picture/sraid20/pb16d781bf332349a25f5f88f2b1bc9ba/fdbcca75.jpg

http://www.imagestation.com/album/?id=4291821277

JACK:gap

 

[Tom Bryant]

Pictures work now

Nice Corvette Jack. Did you get the rods reblanced after the clearancing? Also are you worrried about removing material from the side of the rod bolt boss? It must be ok as there are a lot of stroker motors out there.

Tom

 

[grumpyvette]

JACK the only area that needs clearanceing is a small area on the top edge of the rod/rod bolt about 3/8" wide at about a 45 deg angle on the inside rod bolt only. this type connecting rod is the best to use
http://www.sallee-chevrolet.com/Scat/scathcr.html

because very little if any grinding is necessary for clearance,

 

[Jack]

Tom:
Thanks, it'll be a lot nicer if I EVER finish it! Rods should be balanced (mine will) after clearancing ... mine'll be rechecked/done when I take the rotating assembly in for balancing. When I acquired these rods, they'd been balanced to within 1/2 gram ... but gotta do it again after clearancing. Of course I'm concerned about material loss at bosses ... but my angle of attack was much less severe than other successful examples two machinists related, verbally & w/ sketches... one shook his head saying many cut WAY into the bolt heads ... both suggested a less severe angle usually suffices ... and that many guys go crazy w/ grinder. Also my cam is rather mild so less interferance at rod. Job would've been easier & quicker (far less repetitive clay-measuring) if I'd used steeper angle ... but I avoided the cookie-cutter approach & spent more time; thus removed less material. Yes, there's a lotta strokers running OK with much more material removed ... & some do blow 'cuz of it. My motor WILL have rev limiter at 6200 or LESS ... my combo will probably run outa breath by about 5800 anyway with crank horsepower probably no more than 400 ... likely around 370 ... and, hopefully, tons of low-mid torque. No plans for the drag strip. I'm balancing assembly with new 168T flexplate. There's a small possibility I might get the motor on my Nascar truck racer-buddy's motor dyno for break-in & tune ... but only if I find a smaller, loaner (153T) flexplate setup that's compatible with my external balance-job ... buddy's dyno uses ONLY 153T. If I were assembling a wilder stroker, I'd use an expensive aftermarket rod having more clearance designed into rod profile. This'll certainly be a test for the "I did it myself" boast ... either hero or zero ... & if she lets go, I'll fess up! Proof's in the puddin' ... I think rods'll be fine for my use ... but we'll see.
JACK:gap

 

[Jack]

Grumpyvette:
Cool ... those H-beam rods’re really nice ... I considered same/like rods ... new prices started about $290. For many, those H-beams are the only way. At the end of the day, I’ll have less than $100 & 3-hours my time in clearancing both block & the pink rods w/ bushings, arp bolts, resizing, clearancing & rebalancing ... hopefully they’ll be fine for my mild combo ... dunno yet? I carefully measured clay-ground-repeated through many trials to arrive at profile required for my mild cam ... limiting cut into bolt head much less than others’ ... ground only on cam-side. With great interest I noted your post with links to rod failure analysis graphics ... recall as an FEA done by university lab ... really insightful. A further tip: don’t throw those old parts away yet ... when clearancing rods or block there’s a lotta grit thrown about ... use an old set of sacrificial bearings, an old sacrificial piston (w/ same comp height as new ones) & a sacrificial tc set. A buddy’s dragster (rustang w/ an SBC) has a 4.155” bore 3.875” forged stroker crank motor with long, cap-screwed 3D-type H-beams and a BIG cam ... he too had to grind a little on rods... not as much as mine. You offer a great suggestion on dimension & angle ... it’s much like what’s successfully used by many others. Again, I offered pics of my rods as only a guide. Maybe there’s no single profile/rod-design that’s optimal for most applications ... dunno? If I were building a stroker with much more yield than mine, I’d use an H-beam ... I’ve seen some with through-beam pin-oiling ... Oliver I think ... quite pricey. I didn’t plan this project as a stroker ... it began as a simple 350 rebuild ... but a crank ruined by former machinist triggered a mild, relatively inexpensive stroker project. I expect it to be rather durable ... dunno yet? I’m not expecting performance levels associated w/ well-planned stroker. If I were to purpose-build another sbc stroker, I’d do like Ken and begin with a 400 or 400-type block ... or maybe even opt for a crate. I began w/ a blown-up 350 ... now 388 ... total costs of all the usual new overhaul parts & ms-balancing labor (excluding my labor) plus used prepared rods, used MSD box & coil & revlimiter and following NEW parts: HEI distributor & HD op shaft, Al intake, Al wtr pmp, tru-roller tc set, mild cam & lifters & p-rods & rockers & springs, hyper pistons, cast crank, deep oil pan & pu, balancer & sfi flexplate ... probably under $2000. Will it run OK for mild street performance ... will it be reliable ... dunno yet? Wish me luck!
JACK:gap