Where's Gary? Wouldn't he know what would be the better cam installation setting with his simulators and such?
I do not know anyone here that stroked a motor on a 350. you should be able to put that cam anywhere you want on the retard, advance scale. I never had mine aligned honed for the crank, I got 20+ years on this motor and has seen 6 grand plenty of times. This looks to be a costly motor, I hope you can get the power out of it by what you are doing.
You'll get as much power out of this as your plan details, meaning that you should have that somewhat predetermined by the top end already. Don't worry in ten different directions, just focus on each singular task. Make it fit first. Don't panic about grinding a little bit from the rods just yet, that's pretty easy to deal with. (It's scary when you read the long posts but probably tough to write about in a more simplified way). There's other solutions for getting through this, I just don't want to interject more variables to your crisis.
Ok, we tried installing the cam at -2* 0.050" lift on INT opening= +4* BTDC (card says 3.5*) Max INT lift= 0.356" (card says 0.365") 0.050" lift on INT closing= 44.5* ABDC (card says 43.5) 228.5* duration @ 0.050" on INT. (228.5/2= 114.25 - 4= 110.25) (card says 227@0.050" and 110LC) 0.050" lift on EX opening= 44.5* BBDC (card says 47.5*) Max lift= 0.354" (card says 0.358") 0.050" lift on EX closing= 9* ATDC (card says 7.5*) 233.5* duration @ 0.050" on EX. (233.5/2= 116.75 - 9= 107.75) (card says 235@0.050 and 110LC)
Derek: Swapped out rod #1 with untouched rod #2. Turned until rod hit cam lobe. (Coming up on compression stroke) Removed timing gear set with crank froze. (Rod and cam making contact.) Turned cam so base circle was facing rod area that was touching. Can only get 0.200" to drag through between the rod and lobe. (Using short feeler gauge set) Pulled cam out. Measured base circle on both INT & EXH. INT= 1.0360" EXH= 1.0375" INT lift= 0.356 - 0.200"= 0.156" more clearance required. EXH lift= 0.354 - 0.200"= 0.154" more clearance required. ......am I doing this math right? There was no way to mark the rod with a pen/pencil/scribe....so I took a couple picture showing where the contact area is.
Instead of going through the cylinder with a mirror, if the engine is on a engine stand can you see the rod and cam from the crankcase side passed the crank with it upside down? Derek
Tried that...it's easier to see everything from the #2 cylinder hole. Went to the shop today to let them know we are experiencing a few minor issues with rod to cam contact. First question from them was, "did you degree the cam?" After talking with them, they said to clearance the rod more, just because we can go as far as half way through the bolt...just as long as the dimple isn't removed. But they said if I had a stretch gauge, and a torque wrench, which I do, we can torque the rods up in a soft jaw vise, and see what the average torque required to stretch the bolts to the spec is...(0.0065"....from Derek, but it should be on page 26 of the ARP catalog.) and use that as the torque setting of the rods. (Since the dimple on the bolt may get removed.) Got home, and tried the old hydraulic, flat tappet cam...just for shits and giggles. Since the base circle was way bigger than the roller cam, I figured it would hit too......yup....it hits. So pulled it out, and called TA Performance. Talked to Tim about what issues we currently have, and he suggested I talk to Mike on Tuesday. (long weekend) I gave Tim my name and number, as well as my email, and said it would be better for Mike to come on here, and just read the information, instead of me trying to tell him over the phone. (And to start on about page 22.)
I'm just worrying too much. The more people I talk to, the more I feel relaxed about what has to happen. I'm not sure reducing the base circle of the cam would gain enough clearance for everything, so any amount that is ground off would be "extra" clearance on top of what the rods have to be clearanced. Use my stretch gauge on all the rods, and set them to 0.0065" stretch. Take my torque wrench, and creep up on the torque to see what torque is required to attain the 0.0065" stretch. Take an average of all the readings, and call that the torque requirement for the rods. Remove material from the rods to clear the cam lobes, and have ~0.050" clearance between rod & cam lobes. The number one rod is so close to clearing right now, I don't think I would have to bring past the halfway point of the rod bolt. (On the top of it.) The pictures above are of a non-clearanced rod.
I have Molnar rods and Crower lvl3 cam and rods number 1, 2, 4, 5 and 6 hitted to cam lobe. I had to grind not only rods but end of bolt also.
Possibly, to know for sure how much interference there is the timing chain would have to be removed and with the crank close to where it is in the picture, the cam needs to be spun to the base circle. From there it needs to be measured how much clearance there is between the rod and the cam's base circle. Seeing how the lobe is .365" higher on one side(according to cam card), knowing what the distance between the base circle and the highest spot of interference with the help of simple math he would know how much actual clearance is needed. For example if the rod in the highest interference point at the lowest on the base circle is a distance of .200" then the clearance needed would be; .365" - .200" = .165" + another .025" for safety margin = .190" needed to be ground or machined off of rod on the highest interference point on the correct angle. With the base circle reduced an 1/8" would give .0625" less that would need to be remove from rod if taking off what is needed is to much off of rod. So instead of .190" it would be .1275" rounded up would be .128" or even .125" would be close enough. All above numbers are for comparative example and the real measurement will vary if Ivan measures it. Derek
Sorry Ivan I missed that one, must of scrolled down to the pictures to fast! Or thought is was part of the cam numbers above it and went to the pics to fast? Yes you did do that right, very cool. So you shouldn't be through to the center of the bolt according to that measurement it looks like. You have 2 choices, either grind all the needed clearance on the rod now or have the cam reground on a smaller base circle so you'll have around .060" more clearance and not have to grind as much off of the rods. Or have slightly less if you want more lift while they're at it? And I think at least .025" clearance should be enough, don't go less than that though. So cool, .200 at the base isn't so bad after all! Like I said in an earlier post, people have been dealing with cam clearance issues since people have been building stroker engines. It also looks like the Molnar rods aren't going to be a direct drop in for the sbb 350 after all!(see post 469 of this thread) Derek
This a Stroker build? Anyone roll over a non-stroked crank/ cam motor with Molnar rods and have interfearance?...Sean?
Kind of senseless to buy stronger rods then grind a weak point into them. Just saying. Derek, would the NASCAR take outs have more clearance? They seemed to be very compact.
I can set a NASCAR rod and stock rod together, just to see how much narrower they are, if any. I guess if you used the NASCAR rods, and didn't stroke the crank...only ground it to fit the rods, they would probably work...and you can get them from 6.000" to 6.450" from what I have seen. Derek, We may send the cam back to be reground anyways...for more lift, and more clearance...just to be safe. Since the spec's fall short of what we wanted in the first place. (.356" instead of .365" in this case) And I know that someday, the aluminum heads will be done, and available....so may as well have the cam for the amount of flow they can provide, and just have to swap heads in the future. And with how slow the shop is with our stuff, not really their fault, we could probably send the cam away, while everything gets balanced, and cleaned.
Why not sell your cam and grind another? Or maybe because it doesn't measure up to spec there might be some diplomacy from your cam seller? Grinding the rod for clearance where you are is hardly into a weak point.
