forged rods?

[Demigawd]

I'm rebuilding my motor as you may know with everything alltogather the compression raito is about 12.6 to 1 idk if my connecting rods would need to be upgraded to forged or not I don't want to get all this done and throw a rod and with that said would I need to go with a better crank or not I would think the crank is ok but idk about the rods any info would be nice

[wagoneerhauler]

Why are you going to have such a high CR?  What are you planning to do with your engine once it's rebuilt?  If this is for your daily driver Eagle then I'd say that 12.6:1 is way too high.  You going to need 110 octane or higher racing gas.  Are you working on this with a shop that's doing some machining for you?  If so you should talk it over with them and see what they figure is a safe CR for you to use and what gas you'll want to use. 

[68AMXGOPAC]

How ever did you come up with a figure of 12:6 - 1  ??

[shaggimo]

I take it you want to run on alcohol?  I would upgrade to a forged rotating assembly and ARP hardware throughout the engine, 12:1 is steep and I doubt the stock bottom end would take it in long run.

[eaglefreek]

How ever did you come up with a figure of 12:6 - 1  ??

He's building an engine for E85 which has an octane rating of about 105. As far as needing forged or billet rods, I can't give any advice based on experience, however I would assume if you installed ARP rod bolts and had the rotating assembly balanced, you should be fine. Typically you want stronger rods for higher RPM applications. 12.6:1 is the static compression ratio. What you need to worry about is your dynamic compression ratio which is mostly dependent on your cam choice. But if you have the money burning a hole in your pocket, it would be cheap insurance to get stronger rods.

[wagoneerhauler]

I did not think of you running ethanol or E85.  I don't recall ever seeing it available here in CNY.  I believe it was common in Minnesota when I was there last year.  Will you always be in an area where it is available?  Gas around here only contains 10% at this point.  Unless someone else in the area has seen it? 

[eaglefreek]

I did not think of you running ethanol or E85.  I don't recall ever seeing it available here in CNY.  I believe it was common in Minnesota when I was there last year.  Will you always be in an area where it is available?  Gas around here only contains 10% at this point.  Unless someone else in the area has seen it? 

That would be my concern also. Definitely not a vehicle you will be able travel cross country. Closest station to me is at least 30 miles away.

[68AMXGOPAC]

I have an American Motors performance book.They list the requirements for upgradeing thier engines through I think 4 "stages" of performance , I'll see if it says anything relateing to your question. ( forgot I had it ).

[amcinstaller]

easiest set of forged rods ive heard of is actually either a chebby set or i think someone somewhere (not on this forum) was talking about using import rods. but to do that you have to grind the crank pins down a bit but hey, why not add a hair of stroke to it? aside from the fact that will bring your already astronomical CR even higher 

[Demigawd]

Yea I have e85 readly avalable and if I travel cross country I plan on taking a couple 55 gal dums of either e85 or methonal with me that's why I got the cr so high to make the swap to alochol worth wile forged rods really airnt that much more its the forged crank that will break the bank lol I've already got a set of forged flat top pistons and I'm getting a low rmp torque cam shaft and to get 12.6:1 raito I am doing the 4.0 head swap milling the head 30 thousanths putting my combustion chamber at 53cc going 40 overbored pistons a preformance muti layer steel head gasket which is .043 thick and ill be zero decking the block to put me at .043 quinch hight. U can plug the numbers into a compresion raito calculator stroke 3.895 bore 3.79 combustion chamber 53 deck 0 piston volume 0 and it all pans out to 12.6:1 static compression raito

[tougeagle]

Yea I have e85 readly avalable and if I travel cross country I plan on taking a couple 55 gal dums of either e85 or methonal with me that's why I got the cr so high to make the swap to alochol worth wile forged rods really airnt that much more its the forged crank that will break the bank lol I've already got a set of forged flat top pistons and I'm getting a low rmp torque cam shaft and to get 12.6:1 raito I am doing the 4.0 head swap milling the head 30 thousanths putting my combustion chamber at 53cc going 40 overbored pistons a preformance muti layer steel head gasket which is .043 thick and ill be zero decking the block to put me at .043 quinch hight. U can plug the numbers into a compresion raito calculator stroke 3.895 bore 3.79 combustion chamber 53 deck 0 piston volume 0 and it all pans out to 12.6:1 static compression raito

If you're building this purely to run on E85, you really don't need to have a compression ratio that high. That's an extreme difference from stock to modified as far as engine stress, and proper tuning of the fuel system with EFI (which would have cost you FAR less) it will run E85 just fine. My CR is somewhere between 9.6 and 10 but I don't have enough information to make a good calculation, and it runs E85 with no difference in performance over pump gas other than a slight drop in mileage, and i didn't have to build the motor to do it. I'm just sayin, if you want to make it worthwhile, focus on your fuel system, because proper fuel control has far greater effect on compatibility than internal engine build alone. Plus you won't have much cargo room left after attempting to fit 1 drum in the back....BUT. This is just my opinion.

HOWEVER.. Yes, Hesco makes full forged rotating sets, which include ARP bolts, forged crank, forged rods, forged pistons. They're very costly, a few thousand dollars, but if you're going to go with those specs, there's no avoiding a costly build.

[Demigawd]

LMAO I just stoped laughing at the image of me tring to put a 55 gal drum in my back seat and in the hatch but I have a hitch set up for it I'm going to be installing also so I'm going to get a small trailer to put the drums on I was looking at the 4.060 Stroke crank from 505 preformance they also have forged rods I can get I think there crank is forged and it comes with apr bolts also I may save up and go with that figure if I'm going to do it good I better do it right

[Draekon]

Do you know what dynamic compression ratio you are going to be running?  Dynamic cr has a lot more meaning than static cr

[AMCKen]

I believe Scat (www.scatcrankshafts.com) makes V8 rods that might be adapted. Nick Alfano may have some also.

Propane has a high octane number also - some say 103, others 110. Natural gas is supposedly around 130.

[Demigawd]

I have to get ahold of the people I'm getting my cam from to get some more number but I can figure my dynamic raito in a day or 2