Just wondering how far you guys have successfully pushed the smaller ARP 5/16 rod bolts as far as HP and RPMs go...

Im on the fence about upgrading to 3/8" for the peace of mind, but if enough people chime in and convince me otherwise, I might just keep the 5/16"s...

My setup will be a 92mm x 85mm B18C, naturally aspirated.
Thanks for any input, advice, suggestions, even donations! LOL.

 

they are good for around 11000rpms thats from GRP con rods when they build mine for the d16 and couldnt fit bigger bolts. i've made around 570hp on the 5/16bolts and more than that now. so its all up to you if you want bigger for your safety of the engine

 

I blew a 84x95mm all motor car up on a burnout years ago, the small rod bolt broke on me

 

Wow, 11k rpms? Interesting...I can only assume the lighter Aluminum rods help achieve this due to it weighing, what about half as a regular steel rod?

Eeeek, this is what makes me paranoid. I know increasing the stroke greatly increases the stress on the rod bolts. I was planning on ordering a brand new set of 5/16" rod bolts, but Im thinking I may want to step up to the 3/8" just for piece of mind. Especially after reading your post, LOL (BTW- I used to read alot of your posts on Houston Imports, back when I lived in Houston. Your car always impressed me)

Anyone else pushing these little tiny baby bolts to the limit with success?

 

ive made over 800 hp on the eagle small bolt.... but i was lettin er eat back then !

 

633whp on small bolt eagle rods

 

What kinda RPMs were you seeing? I'm more concerned with RPMs and stroke as I believe this has more of an effect on rod bolts than actual HP...

What do you mean by "lettin er eat back then"?

 

9800 tru the traps..... that hp/rpm wasnst recommended by eagle so i said **** it... hence lettin er eat

 

if u can upgrade to the 7/16 bolt. Do it.... u can find big bolt eagles for under 300 new if u search around...

 

Hmmmmm....

What about getting the larger bolts and having the machine shop step up the holes, re-thread, and re-size the big ends?

Would this be an option? Or is there not enough meat around the holes to step them up?
The 2 or 3 times I've ran Eagle rods, they were with the small 5/16" bolts, and I never really considered upgrading...Those were with 89mm cranks turning about 9k rpms. The extra 3mm stroke has me stressing since the rod bolts are probably the most stressed bolts in the entire engine...

Mikesrex post isn't making me comfortable either, LOL

 

oh.... NA ....just read that..... just leave them.... youll be fine

spunn those on a 1-2-1 **** to 12980 rpm..... put a window in the block but the caps were still on the rods

 

The larger and more standard bolt is a 3/8 bolt, with a 7/16 head


...Just trying to cut down on confusion

 

WERD

 

Made 650 for 3 years on them H22 at 9K Rpms. 1-2-3-2 shift overreved 12k, and used them 3 times... finally over a year and a half later one let go number 1 came out the front. Not even raping it.... I reused them too many times or theyd have been fine. Re ringed once and new pistons early on....



I did upgrade to the 3/8 this time, but im confident if they wouldnt have had 7-8 tqs on them the motor would still be fine.

 

Well, I guess if the bolts didn't break on visits to 12k rpms, I should be OK... I dont expect to make power past 9k and will prob shift around 8.5k for longevity purposes...

Thanks guys. I feel a little better about staying with the small ones now.

 

If you are still in the process of building the motor I would say go with the bigger rod bolts. Even if it takes a lil more time to get parts together, IMO it's worth the added insurance.

 

Dammit. I think youre right. New rods with bigger rod bolts would be much cheaper than a new engine...I like to play it safe rather than sorry. Perhaps the extra cost is worth the peace of mind....Hmmmm.

Does anyone have any input about having a machine shop mod my current rods to accept larger 3/8" bolts?

 

1. Buy new ones.

2. Sell old ones.

3. Profit

 

The size is not everything.. LOL

I would personly never use arp 2000 rod bolts ever again on a high reving engine. Putting stock eagle rods to 9500 daily in a year on a high power streetcar is not what I would do again.. In my appinion it is junk and I will never use it again.. I could upgrade the rods with arp L19 or 625 series rodbolts but those are more expensive then the actuel rods. I am not comfortable with that ether. Get good stuff from the begining and you don´t have to buy things twice.

 

LOL, ok.... Eagles are fine... Like I said:My 5/16 Eagles lasted at 650 WHP beaten to **** for 3 years... I am DEFINATELY not the only one. The car blew up 15ish Transmissions and NEVER did I have any issues with them. Maybe your assembly was sub par???

L19s are much more prone to corrosion as well moreso suited for a racecar. Call ARP and ask them, I did before making my choice on new rod/bolt combo. After talking to one of their ENGINEERS, the 3/8 ARP 2000s were outlined as a better choice for my app, by HIM... Pretty sure he knows whatsup with his own product.

3/8 ARP2000 are PLENTY fine.

Im making 750/575 now revving to 8500-9K and have complete faith.

 

I think this is the route I'm gonna take. Thanks for the input everyone. Now its off to the marketplace to do some shopping. Any recommendations on Eagle distributors, anyone?