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| Rod Knock - what rod/piston options? https://slantsix.org/forum/viewtopic.php?t=62861 |
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| Author: | csheehy [ Sat Sep 22, 2018 7:09 am ] |
| Post subject: | Rod Knock - what rod/piston options? |
Slight ticking turned into full-blown rod-knock. Rebuild time. Here's my question... Are there any non-custom options for rod and/or piston combinations other than the long-rod & 2.2 piston option? This is for a '68 Barracuda, automatic, 3:32 gears, street-performance only (not race), running on 91 octane. I'd like to find a rod/piston combination that offers lighter weight, reduced friction, and holds a tighter seal. I posted my theoretical build a short while ago here >> http://www.slantsix.org/forum/viewtopic ... ns#p463875 and am looking for additional collective input... -C |
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| Author: | Dart270 [ Sat Sep 22, 2018 1:04 pm ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
K1 or Molnar 7" rods and Wiseco Slant 6 pistons. You have a forged crank (75-down) motor, right? Search the web and you'll find them. Campbell Enterprises still sells them? Hope this helps, Lou |
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| Author: | csheehy [ Sat Sep 22, 2018 3:35 pm ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
Lou, Thanks for your response Lou, but I'm looking for something *other than* the long-rod setup. Know of anything else? |
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| Author: | kesteb [ Sat Sep 22, 2018 6:03 pm ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
I am not sure what you are looking for. Your other thread gave some very good suggestions from some very knowledgeable people. Yet, you are looking for more suggestions? |
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| Author: | Dart270 [ Sun Sep 23, 2018 5:11 am ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
I am confused too. What are you trying to build and what is your budget? Lou |
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| Author: | ceej [ Sun Sep 23, 2018 10:05 am ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
Quote: question... Are there any non-custom options for rod and/or piston combinations other than the long-rod & 2.2 piston option?
No, not really. I thought there was a stock 6.7 rod length from K-1/Molnar at one time for those not drinking the long rod cool-aid. (I'm a long rod infidel, so will likely roast in hell.)Everything beyond is custom. Something is going to need machine work. The stock rods a plenty strong for most applications. If your planning to spin it into the stratosphere it'll take something custom. As asked before, what's the plan? CJ |
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| Author: | Dart270 [ Sun Sep 23, 2018 12:49 pm ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
The stock rods are good for at least 300 HP (meaning a 13 sec car that weighs 3000 lbs), and well over 400 if you do not rev above 6000. That is, if you get them rebuilt properly with ARP or other good bolts. Probably that is all you need. Plan to spend $200-300 to get them rebuilt properly with good bolts. The ARP rod bolt set is $60 and I just bought a set from Summit. Best, Lou |
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| Author: | slantzilla [ Sun Sep 23, 2018 4:10 pm ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
R&R in Grant Park, IL will probably build you a set of 6.7 aluminim rods. You do want light, right? The big issue with using a 6.7 rod is that you have to mill the block/head a bunch to get decent compression, and there aren't too many options for light pistons. I have a rebuilt set of 6.7 rods with ARP bolts, and a set of +.100 Ross flat top forged pistons you could talk me out of, but neither would be considered "light". 
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| Author: | Rick Covalt [ Sun Sep 23, 2018 7:01 pm ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
Quote: 3:32 gears, street-performance only (not race)
Stock rods should be fine! It is only a street motor, right?
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| Author: | slantzilla [ Sun Sep 23, 2018 7:07 pm ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
Quote: Quote: 3:32 gears, street-performance only (not race)
Stock rods should be fine! It is only a street motor, right?
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| Author: | Rick Covalt [ Mon Sep 24, 2018 2:39 am ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
Nope, Your good! 
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| Author: | ceej [ Fri Sep 28, 2018 10:42 pm ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
Heathens. The Hooptie saw 5500 rpm once, I will never do that to it again, as the sound was atrocious. (Stroked a bunch, to be sure) But my piston 7.005" rod combination is a lot lighter than the stock configuration at 6.700" A stock engine sees 7000 rpm your gong to see light through the block sooner or later. I vote sooner. Don't do it. Even 6000 rpm is beyond the design with stock parts on a 225. There really aren't any off the shelf rods other than OEM that are going to fit the crank journals in a slant with appropriate pin sizes for pistons that will fit the slant. Something is going to be custom. After-market rods, or Machine Work. Don't give up hope, but working away from the stock rods puts you in experimental territory. Something will need to be modified if it's to fit. To add, I've got an engine going together this winter for my LONG rods. Not messing around with 7.005" rods on this one. Check the Sunday funnies soon. Some know how much I spent on the Hooptie long rod stroker, a few privileged know what I have in the Digger engine. The new engine might actually be expensive.  CJ |
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| Author: | slantzilla [ Sat Sep 29, 2018 12:06 am ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
Quote: Heathens.
Coward! The Hooptie saw 5500 rpm once, I will never do that to it again, as the sound was atrocious. (Stroked a bunch, to be sure) But my piston 7.005" rod combination is a lot lighter than the stock configuration at 6.700" A stock engine sees 7000 rpm your gong to see light through the block sooner or later. I vote sooner. Don't do it. Even 6000 rpm is beyond the design with stock parts on a 225. CJ I shifted my other motor at 6700 and 6500 on hose. Never even nicked a bearing in it.  But yeah, I really don't recommend it to too many. I told Mike I'm shifting his old motor at 6700ish. There was silence on the phone for a minute.
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| Author: | Dart270 [ Sat Sep 29, 2018 3:08 am ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
As a side note, it is interesting/funny how people's version of cheap or expensive for building a motor can be so different. To all the car magazines these days, a cheap engine is around $10-20k, and a "junkyard" engine takes $5k worth of upgrade parts. A "regular" engine might be around $20-30k. Lou |
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| Author: | Rick Covalt [ Sat Sep 29, 2018 5:07 am ] |
| Post subject: | Re: Rod Knock - what rod/piston options? |
I haven't spent $20K in 30 years including all the cars ,engines, paint jobs, trailer and truck to pull it.
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