Harland Sharpe 1,7 RR's vs T&D

[Greg Good Cylinder Heads]

This is what the graph looks like on an engine with a weak pushrod. Blue line is the cam profile, red line is what the valve is really doing. Long story short, when the pushrod flexes it will cause the valve to *loft* on the opening ramp of the cam lobe and crash down onto the nose of the lobe.

 

[Greg Good Cylinder Heads]

And on the left is a Gen 2 Viper cam that is the result from this. You can see where the lifter was slamming onto the top of the lobe like an impact hammer.

 

[Vipuronr]

Great illustration to demonstrate the point. Never really thought much about the pushrods other than in having the correct length/ diameter. Honestly never thought about them flexing, except possibly when very stiff hi-perf springs were added to the mix.

Thanks for showing!

 

[BW96snake]

Greg, Thanks for sharing some great info!

A related question:
What would you recommend for an owner who wanted to add RR and new pushrods now, and at the same time position oneself favorably for future head work (by for example sending the OEM heads to you for porting and polishing.

In my case, I have the 708 cam, high-flow cats, 3" cat back, smooth tubs, flash to match.. thinking about headers, RR and porting of head (and maybe intake)

If you would recommend to only you Jessel for all of that, I wouldn't want to install something else now.. I would rather spend the extra $ now, even though it's overkill until all pieces are together.

Thanks for sharing your knowledge!

Tony, it's usually a solid 15 whp.

I'll post a Spintron graph later showing what a weak pushrod can do.

If I could fit a truck axle in there for a pushrod, I'd do it. No such thing as a valvetrain that is too stiff.

 

[plumcrazy]

BW96, if your e going to do heads, "might as well" do a good cam too. talk to GG on this. he sells some great combination's.

 

[BW96snake]

Will do, thanks!

I guess I was thinking that the OEM 708 lumpy cam was a preferred choice since so many switch to it, but you're saying there are better ones out there, especially if the heads would get worked on.

BW96, if your e going to do heads, "might as well" do a good cam too. talk to GG on this. he sells some great combination's.

 

[plumcrazy]

if youre doing heads, get a better cam. not much more money, same amount of work and worth it. GG will tell you about it. nobody better !

 

[costanZo]

if youre doing heads, get a better cam. not much more money, same amount of work and worth it. GG will tell you about it. nobody better !

Plum, in my case I'm not doing head work yet. Not sure if I ever will, but I'd like to..and if I do I most likely would next year or the year after. Anyway, my 96 GTS currently has the stock 708 cam in it. If this summer I'm doing headers, rollerrockers and some other mods is the 708 cam the best cam to have? I was told, I can just upgrade the cam later when I do heads, if I do them. I figured there was no point in upgrading the cam now since I won't benefit from it yet, and would most likely have to buy other parts to compensate the more aggressive cam anyway.

 

[plumcrazy]

i agree, if not doing heads, its not such a big deal.

 

[costanZo]

Nice, thanks for the info.

i agree, if not doing heads, its not such a big deal.

 

[Jack B]

I don't think I will change the pushrods, unless I hear that it is necessary. I never track my car and don't plan on modding the car much more than where it is now. Motor will remain stock with the exception of the HS rr's. If I am not changing the cam or the springs, why would the pushrods need to be changed...unless they sit better in the new rocker or the change to 1.7 requires new rods.

After changing the rockers, the odds of the existing push rods having perfect geometry are very slight. You really should find what the pattern looks like on the valve stem and secondly, see where you are relative to the range of the adjusters.

I am not sure about the HS's, but, on the T&D's you do not have a lot of range for error. Depending on the position of the adjuster you can either weaken the rocker or close off the oil flow. Take a look in the "How To" write-ups, there is a good article on adjusting push rods.

 

[Greg Good Cylinder Heads]

I good rule of thumb on the T&D's is....as long as the adjuster is not below the top of the jam nut, oil flow will not be hindered.

On the HS rockers, I don't believe they have internal oiling to the trunnion, so it's not as big an issue.

I would put stiffer pushrods in even if the cam and springs are stock. The pic of the damaged cam I posted above is from a bone stock '99 GTS (708). Stronger pushrods probably would have prevented it.

 

[costanZo]

I good rule of thumb on the T&D's is....as long as the adjuster is not below the top of the jam nut, oil flow will not be hindered.

On the HS rockers, I don't believe they have internal oiling to the trunnion, so it's not as big an issue.

I would put stiffer pushrods in even if the cam and springs are stock. The pic of the damaged cam I posted above is from a bone stock '99 GTS (708). Stronger pushrods probably would have prevented it.

Greg, so if I'm doing the Gunmetal Silver Shaft mount T&D Roller Rockers or Jesel Shaft Rockers within the next few months and I already have the 708cam stock in my car(96 GTS)and stock springs. Are you saying you suggest I also get stronger/stiffer pushrods instead of leaving the stock ones that are already in my car? If so, would I need to upgrade anything else in the process of getting new Rockers? By the way, sorry if this question seems stupid, but are either of these rockers I just mentioned automatically 1.7 ratio or could they also be 1.6? Regardless, I would assume to go 1.7 in the end anyway.

Also, what is your preference on the Shaft mount T&D Rockers vs Jesel Shaft Rockers?

 

[Vipuronr]

I'm pretty sure Greg answered the question about pushrods above, about six posts up. Here is what he said (couldn't copy the chart for some reason:

This is what the graph looks like on an engine with a weak pushrod. Blue line is the cam profile, red line is what the valve is really doing. Long story short, when the pushrod flexes it will cause the valve to *loft* on the opening ramp of the cam lobe and crash down onto the nose of the lobe.​

My 2-cents is, if you're going to put in that level of rocker (more expensive than HS), then why would you not just go for the better/stronger pushrods as well?

 

[costanZo]

I'm pretty sure Greg answered the question about pushrods above, about six posts up. Here is what he said (couldn't copy the chart for some reason:

This is what the graph looks like on an engine with a weak pushrod. Blue line is the cam profile, red line is what the valve is really doing. Long story short, when the pushrod flexes it will cause the valve to *loft* on the opening ramp of the cam lobe and crash down onto the nose of the lobe.​

My 2-cents is, if you're going to put in that level of rocker (more expensive than HS), then why would you not just go for the better/stronger pushrods as well?

Hey, thanks for following up. I was originally told by upgrading to the more expensive Rocker, I would be able to keep my stock 708 cam which I would benefit from over an aftermarket cam because I wouldn't have to upgrade and change my valve train with aftermarket springs, retainers, lifters, valves...etc which I assumed meant pushrods as well. However, I was told I would only have to upgrade all of this stuff if I decided to upgrade to a more aggressive cam, especially if I upgraded the heads and had them ported.

 

[Vipuronr]

Agreed, that is the same thing I was told when looking into changing cam, but then found out that the 708 stock cam was pretty good. What I've also been told is the change in rockers to 1.7 ratio actually increases the cam's lift a little bit, maybe 10 or so points and adds to the aggressive sound it already has.

According to Greg, the change to stronger pushrods helps insure that the valve train tracks the cam more accurately by not flexing (as much). He also showed in his second post the effects of flexing causing the lifters to "bang" on the cam lobe, scoring it - check out his picture.

So, net net, seems the change in pushrods is a good idea for many reasons! I know, after reading Greg's answers, I will definitely go for the stronger pushrods if and when I change rockers.

 

[costanZo]

Agreed, that is the same thing I was told when looking into changing cam, but then found out that the 708 stock cam was pretty good. What I've also been told is the change in rockers to 1.7 ratio actually increases the cam's lift a little bit, maybe 10 or so points and adds to the aggressive sound it already has.

According to Greg, the change to stronger pushrods helps insure that the valve train tracks the cam more accurately by not flexing (as much). He also showed in his second post the effects of flexing causing the lifters to "bang" on the cam lobe, scoring it - check out his picture.

So, net net, seems the change in pushrods is a good idea for many reasons! I know, after reading Greg's answers, I will definitely go for the stronger pushrods if and when I change rockers.

Thanks for the input man.. I really appreciate it, that helps me a lot. Which pushrods were you going with? Do you have a link to them? I'd like to check them out since I plan on upgrading my Rockers soon to either the Shaft mount T&D Roller Rockers or Jesel Shaft Rockers as I stated earlier. Unless these Rockers would need a different set of pushrods? Would the Harland Sharpe Rockers require different pushrods then the two sets of Rockers I just mentioned? Or does it not matter and have no relevance...

Also, I think I'm confusing myself. Are the stock Rockers in my viper and yours a 1.6 ratio? So basically any rockers you buy... whether it being Harland Sharpe, T&D or Jesel..will all be 1.7?

 

[Vipuronr]

You're quite welcome! I tend to buy my stuff from Sean and he has both the HS 1.7 rockers and the pushrods:

HS Rockers:
Harland Sharp 1.7 Ratio Roller Rockers, 92-02 Viper - Camshaft and Valvetrain - Roe Racing

Pushrods:
Pushrods, High Strength 92-02 Viper - Camshaft and Valvetrain - Roe Racing

While I might be able to save a few dollars going somewhere else, I trust him because he is all about Vipers. Jon at Parts Rack doesn't show HS rockers, only T&D's, did not notice if he also has the pushrods to go with them.

Of course, again, only Chuck works on my car so he would end up ordering the correct parts...not sure who he uses as a supplier, but Roe is one of them.

To answer your other question, I think the stock rocker is 1.7 and all these mod rockers are 1.7, this the slight increase in cam lift.

 

[costanZo]

Thanks for the links!

Oh..so those pushrods are made by T&D? Maybe I'll get the T&D Rockers to match

JonB doesn't show several things on his site, but he can always get you anything you want. I bought my KW2s off him, and they weren't on his site. Also, those [FONT=Trebuchet MS, Geneva, Arial, Helvetica, SunSans-Regular, sans-serif]Speedtactics Viper Gills[/FONT] I posted about, which I also just purchased from him on Tuesday, weren't on his site either.

So if the Stock Rocker and all these aftermarket rockers are 1.7, which one's are 1.6?

You're quite welcome! I tend to buy my stuff from Sean and he has both the HS 1.7 rockers and the pushrods:

HS Rockers:
Harland Sharp 1.7 Ratio Roller Rockers, 92-02 Viper - Camshaft and Valvetrain - Roe Racing

Pushrods:
Pushrods, High Strength 92-02 Viper - Camshaft and Valvetrain - Roe Racing

While I might be able to save a few dollars going somewhere else, I trust him because he is all about Vipers. Jon at Parts Rack doesn't show HS rockers, only T&D's, did not notice if he also has the pushrods to go with them.

Of course, again, only Chuck works on my car so he would end up ordering the correct parts...not sure who he uses as a supplier, but Roe is one of them.

To answer your other question, I think the stock rocker is 1.7 and all these mod rockers are 1.7, this the slight increase in cam lift.

 

[Vipuronr]

I think the stock rockers are 1.6 and the aftermarket are 1.7. If the pushrods are by T&D, I would probably get the T&D rockers to go with them. But, I'm not an expert in this, so I would get an expert opinion before buying anything.

I know Jon carries lots of things not on his site but, at the end of the day for me, it's up to Chuck where he wants to purchase the parts or, he will tell me where he thinks I should go and what to order.

 

[ViperTony]

I think the stock rockers are 1.6 and the aftermarket are 1.7. If the pushrods are by T&D, I would probably get the T&D rockers to go with them. But, I'm not an expert in this, so I would get an expert opinion before buying anything.

I know Jon carries lots of things not on his site but, at the end of the day for me, it's up to Chuck where he wants to purchase the parts or, he will tell me where he thinks I should go and what to order.

I went with Trend 3/8" Double-Tapered push-rods. They're double-tapered, stronger and lighter. And I was able to reuse them when I did my heads/cam.

 

[costanZo]

I went with Trend 3/8" Double-Tapered push-rods. They're double-tapered, stronger and lighter. And I was able to reuse them when I did my heads/cam.

Good to know, since I also hope to do heads/cam next year.. So maybe that would be good for me as well.

 

[ViperTony]

Good to know, since I also hope to do heads/cam next year.. So maybe that would be good for me as well.

Results may vary. I lucked out with the push-rods after doing head/cam work as the length of the push-rods was sufficient.

 

[Dom426h]

Im a bit concerned about the claimed power gains since i have not seen any before/after dyno results. One persons negative experience that i have heard of is -FROG-'s who actually lost alittle power when going to 1.7RR's
http://forums.viperclub.org/rt-10-g...s-98-viper-gts-new-track-times-2-18-11-a.html
I do understand that the same motor power rating can change from day to day on the same dyno even SAE Corrected, but even with a variance of 5-10hp from his previous 461HP / 507TQ pull i would expect RR's to put down at least the Same power. but no his power actually dropped to 455HP / 499TQ.

I currently put down about 460/500 SAEdynojet with just about every bolton Without RR's. Mine & -FROG-'s motors are among the highest bolton dynoing Gen2's that i have personally seen. If i do RR's should i expect 475/515 or 455/495

Imagine spending 1,400bucks on something that could possibly rob you of power or simly do nothing. Now i'd still be pissed if i spent the 700 on HS's and didnt gain more than a few hp/tq.



Roe says "Conservative performance gains are 17-20 RWHP & RWTQ on a naturally aspirated engine"

Greg Good says "a solid 15whp"

-FROG- says negative 6hp.

I would greatly appreciate it if one of the tuners would dig up a dyno graph of before/after RR's. I'd like to see the entire range of power, Not just claimed peak numbers.

 

[ViperTony]

I didn't feel a thing when I did rockers. Hard to feel 15rwhp on a 450hp engine. Personally, I think rockers (in and of themselves) are a waste of money. Coupled with other mods (exhaust,headers,intake,tune) probably worth it.

 

[costanZo]

I didn't feel a thing when I did rockers. Hard to feel 15rwhp on a 450hp engine. Personally, I think rockers (in and of themselves) are a waste of money. Coupled with other mods (exhaust,headers,intake,tune) probably worth it.

Well, I already have exhaust, getting headers, have intake(might be looking to upgrade it if possible), and getting a SCT Tuner. So I think RRs will do me justice. To save myself $600, I'm probably just going to get the Gunmetal Silver Shaft mount T&D Roller Rockers instead of Jesel. Still uncertain on which push-rods to get though from what you're saying Tony since the T&D ones seem good as well. I'll have to ask around or do some more research.

 

[plumcrazy]

they make a bigger gain on a SC car. like tony said, its probably a waste on most cars. hard to feel a 15rwhp change regardless of what some say.

 

[Dom426h]

Coupled with other mods (exhaust,headers,intake,tune) probably worth it.

well -frog- had all of the above and didnt make jack with RR's. That was my point. Ill add that his dynos were done at a reputable tuner, A.R.T.

CostanZo ? How would you feal if you ended up spending upwards of $2,000 (from the td rr's, pushrods, install) and ended up with no power gain? If you threw everything on at once and then dynod you wouldnt even know the diff. I suggest starting with headers(as they are guaranteed to make power) then getting her on the dyno to get a baseline with and without tune. Then think about the RR's. (this is where I am at...)

 

[Greg Good Cylinder Heads]

Frog's experience's is the exception. I'll tell you one thing, you can't put a .600"+ lift cam in a Viper along with the springs that go with it, without using roller rockers. The stock ones can't handle the spring pressure.

I have a Dan Jesel story that fits this situation. A guy bought a belt drive from him one time, installed it and didn't pick up a single hp, or so he claimed. So he called Jesel to complain and Dan told him that some engines run faster with chains.

Dan didn't want to argue with him.

 

[Dom426h]

Frog's experience's is the exception.

Good to know. Thats what I wanted to hear

Some good info here from DYankee&GregG:
http://forums.viperclub.org/rt-10-gts-discussions/597419-pushrod-length-harland-sharps.html
and
http://forums.viperclub.org/rt-10-gts-discussions/633695-roller-rockers.html