LS7 high effort engine build, Ti Rods & Bolts
10-17-2018, 01:06 PM
#1
LS7 high effort engine build, Ti Rods & Bolts
I'm piecing together an ls7 that is going to be pretty gnarly. I am getting close to sending the bottom end to the machine shop, but need to make a decision about what to do with rod bolts.
Plan is drag, half mile, mile, road race, and some street use. RPM range will be at least up to 7800, and estimate that I'll be nearing 800 horsepower flywheel.
I hadn't really kept up with the times to know that Katech bolts were discontinued.
I know ARP bolts run the risk of distorting the big end of the rod. I've had good luck with them on other engines without needing to resize the rod. I don't mind having them resized, but I have read that some people claim you can't without damaging the coating on the rod?
Is it possible to resize the Ti rods as you would a normal stock rod?
Plan is drag, half mile, mile, road race, and some street use. RPM range will be at least up to 7800, and estimate that I'll be nearing 800 horsepower flywheel.
I hadn't really kept up with the times to know that Katech bolts were discontinued.
I know ARP bolts run the risk of distorting the big end of the rod. I've had good luck with them on other engines without needing to resize the rod. I don't mind having them resized, but I have read that some people claim you can't without damaging the coating on the rod?
Is it possible to resize the Ti rods as you would a normal stock rod?
10-17-2018, 01:17 PM
#2
Le Mans Master
Yes it is. Get some ARP 2000's and have the big end machined for them...too easy for any reputable engine shop. If they mess up the coating, they should fix it.
But at the same time, your build sounds like it's going to be smashed on pretty frequently. There are plenty of great rod options out there...so why bother with the stockers?
But at the same time, your build sounds like it's going to be smashed on pretty frequently. There are plenty of great rod options out there...so why bother with the stockers?
Last edited by Pb82 Ronin; 10-17-2018 at 01:21 PM.
10-17-2018, 01:18 PM
#3
Been following this aspect of LS7 building as well. From what I have confirmed, the Katech rod bolts are no longer available as their supplier unexpectedly went out of business. In some of the builds I've read about, using the ARP's can distort the big end if not resized. Which isn't a big deal unto inself but then the rods need to recoated which Calico used to do but does no longer. Its seems the current state of things is that we are missing a coating supplier who can reapply the anti scuff to the rods. Hence why many go to a normal forged bottom end when rebuilding for max use. If anyone knows something different please correct me.
10-17-2018, 02:09 PM
#4
I want the Ti rods for their performance benefits, and they're sexy. I believe they're part of the last 5-10% that's going to add up to get me to my goal.
Do we know for sure that resizing the big end damages the coating? I read the thread about it so I know what you're referring to - never would have considered it to be an issue. I find it hard to imagine that a clean-up hone to true it up would flake off a coating? We're talking less than a thou overall if you don't grind the caps.
Do we know for sure that resizing the big end damages the coating? I read the thread about it so I know what you're referring to - never would have considered it to be an issue. I find it hard to imagine that a clean-up hone to true it up would flake off a coating? We're talking less than a thou overall if you don't grind the caps.
Last edited by ls404fd; 10-17-2018 at 02:17 PM.
10-17-2018, 03:52 PM
#5
Le Mans Master
I know titanium is sexy, I completely agree. But, it has it's limitations just like anything else. If I'm putting the beans to any hard core build, I'm going to match all parts accordingly. Keep in mind, the rod is only one part of the equation. There's weight that can be shed in the pistons, ring package, etc. IMO, I'd rather have a stronger rod and super strong rod bolts with the lightest pistons possible. If they weigh anything even close to the stock rod/piston combo, you won't even notice a difference in engine speed. Most of it is imperceptible anyway.
10-17-2018, 06:30 PM
#8
Pro
I was adamant to reuse my stock rods when I rebuild my motor, but not sure it’s worth it anymore. I’m not worried about how strong they are but I’m worried about the coating. Pulling the motor after having it forged due to the rod coating wearing off would suck big time. Just my opinion.
10-17-2018, 07:52 PM
#9
I was adamant to reuse my stock rods when I rebuild my motor, but not sure it’s worth it anymore. I’m not worried about how strong they are but I’m worried about the coating. Pulling the motor after having it forged due to the rod coating wearing off would suck big time. Just my opinion.
I had 92k miles on those rods but the coating finally wore off, causing a spun rod bearing and another rebuild. Going aftermarket rod now.
Last edited by FNBADAZ06; 10-17-2018 at 07:53 PM.
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Racingswh (10-17-2018)
10-17-2018, 08:17 PM
#10
My short is only supposed to have 19k miles. I’m definitely going to be looking at them when I disassemble the bottom end.
Out of curiosity now I’ve started pinging a couple shops about some coating options. There’s no reason why Calico would be the only option.
Out of curiosity now I’ve started pinging a couple shops about some coating options. There’s no reason why Calico would be the only option.
10-17-2018, 08:29 PM
#12
Le Mans Master
Not disagreeing with you man. Ti rods are awesome. All I'm saying is you don't have to limit yourself if weight is all you're concerned with. You can make the difference in other components.
10-17-2018, 09:52 PM
#13
Has there been a single failure linked to the OEM LS7 rod bolts? Just use oem and don't look back. I contemplated the same thing for my build and was worried about the big end distortion. OEM rod bolts for the win
10-17-2018, 09:55 PM
#14
Drifting
I’m using OEM rod bolts with stock rods and forged pistons in my 800+ whp boosted Z. No issues for the past 18 months, but I’m not pushing the car to 7800 rpm, either.
10-17-2018, 10:26 PM
#15
Le Mans Master
RPM does matter in rod bolt happiness.
10-18-2018, 12:31 AM
#16
Now, the coatings wearing off, causing catastrophic rod and rod bearing failures on rods #1 and 2...that's been popping up more frequently lately.......me being one of them.
10-18-2018, 12:36 AM
#17
10-18-2018, 07:45 AM
#18
Good info here. I was unaware of the potential coating issue when “truing” the rods. I agree with the other guy above though.. you can offset the weight difference in other components(pistons, etc).
Is it even noticeable when going WOT as far as Ti rods vs forged in an LS7? I can’t imagine you being able to feel the difference in the way it revs and builds power.. maybe I’m wrong ?
Is it even noticeable when going WOT as far as Ti rods vs forged in an LS7? I can’t imagine you being able to feel the difference in the way it revs and builds power.. maybe I’m wrong ?
10-18-2018, 08:28 AM
#19
Good info here. I was unaware of the potential coating issue when “truing” the rods. I agree with the other guy above though.. you can offset the weight difference in other components(pistons, etc).
Is it even noticeable when going WOT as far as Ti rods vs forged in an LS7? I can’t imagine you being able to feel the difference in the way it revs and builds power.. maybe I’m wrong ?
Is it even noticeable when going WOT as far as Ti rods vs forged in an LS7? I can’t imagine you being able to feel the difference in the way it revs and builds power.. maybe I’m wrong ?
Last edited by FNBADAZ06; 10-18-2018 at 10:46 AM. Reason: remove incorrect information
10-18-2018, 08:30 AM
#20
Calico recoated my rod cheeks 3 months ago... they stopped since then?