Ok, sorry, I don't know anything about the Grand Prixs

A guideplate bolts on under the rocker studs and has holes in it for the pushrods to ride through. Here is a pic I found in the search engine (Thanks to chrism400 for the pic) The guideplates are only required if the rockers being used are not self aligning.



Thomas.

 

Do the 1.7s change the way it sounds at all?

just curious

 

Not too sure? If anything, I'm sure the valvetrain will be a lot louder; but hopefuly the LT4 valve covers will take care of some that noise.

As for the engine sound, not sure if they will add a bit of 'lope' or not? Being the duration remaining the same, I'm expecting it not to do much to the engine/exhaust sound .... but I really don't know

I'll let ya know after the install is done. As of now, I'm planning the install the weekend of Feb 4th.

Thomas.

 

I had some Harland Sharp 1.9s on my Grand Prix and they came with a similar "pedestal or guide". There will be little to no change in exhaust note. Im sure someone with an ear kin to the LT1 could detect it, it wouldnt be anything spectacular, as far as a power gain, stepping up lift .2" is awesome!

 

Just an update.

After doing some more research on the Comp 987 springs, I've decided to send them back and get the Comp 26918 springs instead. I've researched and found contradicting information on weather or not the 987 springs will clear the valve seal. I spoke to 2 techs at Comp Cams, and both said the inner spring would rub the valve seal. They both stated I would need the valve guides machined down for clearance. Several people on this board reported the 987s working with stock seals, and others reported they needed to install spring locators for them to work. Considering the locators are ~$65, and the price difference from the 987s to the 918s (with steel retainers) is around $75, I opted to go for the 918s.

Another factor which made me switch to the 918s is the spring pressures:

• The 987s have an open load of 388@1.2 with a rate of 344 lbs/in. Since my lift is only going to be .520, the max compression I will see on the spring is 1.23, that gives me an open valve spring pressure of 317.08 lbs/in with a 1.75 seat pressure of 138.2 lbs/in.
  
• The 918s have an open load of 318@1.2 with a rate of 313 lbs/in. With the .520 lift, the max compression on the spring is still 1.23, which gives me open valve spring pressure of 308.41 lbs/in with a 1.75 seat pressure of 145.65 lbs/in.

Both springs will bind at 1.15, so I am far from binding with either spring. But as you can see, the 918 will have less pressure when the valve is open, which was a concern for me in terms of lifter life and cam wear. Also with the 918s having no reported install issues at all, it seems a no brainer to spend the extra $75 or so and go with them.

Still planning the install for Feb 4th, so plenty of time to make sure I have the parts I'll need to do it once, and do it right.

Thomas.

 

Well, the install is finished

The final parts list was:

• Scorpion Rockers SCP1026 http://www.flatlanderracing.com
• Comp Cams Hardened Pushrods p/n 7808-16 Comp Cams (I have since removed these and installed 7.150" chromoly pushrods - p/n: 7939-16 - to correct the valvetrain geometry)
• Comp Cams 918 Springs 26918-16 CompCams
• 10* Comp Cams Steel retainers p/n 759-16
• 10* Comp Cams Super Locks p/n 611-16
• GM Valve Seals 10212810 & 12564582 http://www.gmpartsdirect.com
• GM Guideplates 14011051 http://www.gmpartsdirect.com (these needed modification -- keep reading to see why)
• ARP 7/16 Studs 134-7103
• Comp Cams Shim Kit p/n# 7453
• Engine Assembly Lube
• Locktite
  
  LT4 Valve Covers & Hardware From Jason Cromer
• LT4 Valve Covers p/n 12552321 & 12552322
• 8 Valve Cover Screws p/n 10108675
• 8 Valve Cover Studs p/n 10108674
• Mobil 1 Oil Cap p/n 12555685
• LT4 Breather Hose p/n 12557604

The install went great; long (10 hours long) but wasn't too hard.

I did cyl #1 first. Removed the 2 rockers and studs. Installed the guideplate and new studs. Then removed the springs and mic'ed the install heights. Both mic'ed up to about 1.76, so no shimming needed. I then installed the new springs, retainers, locks and pushrods. then I covered the top of the valve stem with a sharpie and installed the rockers. I set the lash and roted the motor 2 full revolutions by hand. I then removed the rocker to look at the valve stem with the sharpie. The roller is riding just a hair off of center, but was so close, I decided the Comp Cams pushrods were an appropriate length. I changed my mind on this being appropriate after This Discussion

I then did the rest of the drivers side, and only had to shim one spring with a 0.015 shim to get it to the 1.76 install height the others were at. Once the drivers side was done, I fired the motor up and set the lash on the rockers with it running. Then I placed the LT4 cover on and fired it up again with my hand on top feeling for rocker contact; there was none!

Next I started on the passenger's side. I had to shim about half of the pass side springs to get to the 1.76 install height I wanted. One needed a 0.030 and the others only needed 0.015 shims. After all the pass side was installed, I fired the motor again and set the lash with it running. Then I placed the driver's side LT4 cover in place and fired it up checking for contact; again, there was none

So it's definite, the LT4 Valve Covers will clear the Scorpion 1.7 Roller Rockers without modification. If you want to use LT4 covers with guideplates though, you must use the GM plates; as they are notched between the 2 guides for the valve cover supports to clear. I saw other posts about people using non-GM guideplates with the LT4 covers, and they had to clearence the cover supports because the guideplates were not notched like the GM ones are.

The only proplem I am having now is the intake rocker on #2 cyl will not stop clacking. When setting the lash, I loosen it until it clacks loudly, then tighten until the noise is gone, then 1/8 turn more. After aprox 10 seconds, the clack comes back. If I tighten another 1/8-1/4 turn it gets quiet again, but will come back after another 10 seconds or so. I think this is a sign of a bad lifter, but haven't figured it out yet.

Anyway, just wanted to post an update for anyone who is interested. I have plenty of pics, but nowhere to post them.

Thomas.

 

Did you use the 4705 seats or the stock seats?

 

I used the stock locaters. I did notice the 918 spring did not fit as nicely on the stock locater as the stock springs did, and wish I had ordered the locaters for the 918s. I decided to go with it as is, considering so many other's have also used the stock locaters with these springs.

Thomas.

 

Id really like to see those pics.

Go to cardomain.com and just start a page and upload.

It takes only 5 10 minutes.

Great job btw - thanks for spending the time to ask the questions in a intelligent and logical manner.

So you didn't mention if you were happy with performance. Still worrying about the lifter probably aye.
Cant say I blame you- Well better to find it this way than otherwise!
Just finishing new cloyes roller - elect wp - and new opti install as well as converted and tuned OBD1 for my 96'. Let me know about results when you figure out clanking noise.

thanks again

 

I have Isky 235D's on my '95 Z28. They require "spring locaters" as told by the shop that installed them. I think locaters are just shims. The springs are good for up to .550" valve lift. I am nearing the end of installing a 501 comp cam. I am using self-guided stamped 1.6:1 rockers for a total lift of
.527" on the exhaust side. Isky's rating does have a built-in safety margine.

 

I actually have an old cardomain account I forgot about. When I have time, I will upload the pics and post a link.

Not sure on the performance yet. As you said, I would like to sort out this clacking noise 1st. I am not going to drive it until I get it figured out. I will be looking into it tonight after work to see if I can determine the issue. If it ends up being the lifter, I'll replace all 16 with GM OEM lifters. Then I can test out the new upgrade

Thomas.

 

Just curious, would the LT4 springs work in this application? Or would the be too close to coil bind? Ive been contemplating this upgrade because i dont plan on messing with a new cam for quite a while, but I would like to add a lil more power. And yeah, pics are always welcome. You got a total for all the parts?

 

I considered several different springs, including the LT4s, and decided on the Comp 918s. You can read my reasons why in the other posts of this thread. I don't think the LT4 springs are enough for a 1.7 ratio on a stock cam.

I didn't total the parts cost up ...... I thought about doing it, but figured I would have buyer's remorse if I saw the total (especially with the LT4 covers and hardware added in)

I got all the GM parts from Jason Cromer and everything else through Shawn at Speed Engineering.

I'll work on getting the pics up when I get home after work today.

Thomas.

 

I did the 1.7 on a stock cam about 4 years ago or so. Here's what I had...
Crane Variable Ration Rockers set @ 1.7:1 intake & exhaust
ARP 7/16" rocker studs
Isky 235-D springs
GM 10185066 spring locators
GM 14011051 guide plates
Moly pushrods from Thunder Racing #99-PR7150
Setup ran great and I'd spin it to just over 7K on some passes... no problems.
Steve...

 

407 before tax w.o new rods - rods are about 40 50bucks

say $450 with rods.

Inclds ;SCP1026 1.7SBC7/16 Rckr Arms $222

ARP-135-7102 studs $29.88

ISK-235D springs $96.69

GM # 14011051 guides 16.96

GM # 10212810 INTAKE STEM SEAL 2.6

gm # 12564852 EXHAUST STEM SEAL 4.96

GM # 10185066 SHIM-VLV 33.92

$407