truedualws6

I finished the install of the parts shown in this post> https://www.camaroz28.com/forums/sho...d.php?t=599108

The significant change was removing 7.05" pushrods and installing 7.30" pushrods. To do this required new rocker studs and swapping all this out. I ended up not using the ARP locks since they are taller than the Comp locks. I did the play-doh test and just barely cleared the LT4 covers with the Comp locks. Everything went together fine.

I did have oil getting past the ARP sealant used with the original rocker stud install, and this was with only 400 miles on things. What ever you do, never use ARP sealant on rocker studs. I did a super clean on the threads and new studs and used Permatex #2 this time. The reason I was pretty sure the oil was getting sucked into the intakes is a sudden increase in oil consumption. Up to about 300 miles there was no oil consumption and then between 300-400 miles I used about 1/5 of a quart.

The initial start up was a bit rough as all the crap burned off but the car settled into a nice cold idle after about 30 seconds. My initial reaction is that the valvetrain is a tad quieter (my wife also says it's quieter). On the test drive it seemed very smooth and ran strong. We'll see how things go after a few thousand miles. The contact pattern for the roller on the valve is offset towards the exhaust side, but is about .08" in from the edge. The sweep should be about half of what it was previously, which was in the .10" range. Based on the mid-lift literature this should be the optimum geometry since I could not go any longer with the pushrods.

Based on the paper study there should be less wear on all the parts. Time will tell if works for the long haul. If everything holds up the morale of the story is there is no reason to run anything other that stock length pushrods on H/C LT1's with rocker studs.

ACE1252

Reading through some of your old posts, I was a little worried about buying the 7.20" pushrods for my CC503 swap(I bought the pushrods before learning how to check the length).

However, now I'm not so worried seeing as how you are now going longer(other posts say that 7.20" for CC503 is fine). Think you'll have any guideplate issues with the rods this long? I guess that is the issue I'm worried about. Guideplate wear.....any abnormal wear seems to point to a pushrod length issue(from what I've read).

wrd1972

Still want to see the pics of the sweep and roller placement.

truedualws6

I've got some pics. Once I pulled them off the camera they were not as crisp as I would like, but I'll post them up. I many just crop the valve stem and sharpen them up. Have not had time to mess with it yet.

truedualws6

For most LT1 H/C builds the worst case is probably similar to mine with longer valves, very little milling on the heads and rocker studs. If I ended up OK with 7.30" pushrods then anything shorter will just move the contact pattern closer to the center of the valve stem. The main point is not to waste money on another set of pushrods (like I have done). I now have 7.05, 7.20 and 7.30 pushrods when 7.20" would have been fine. I just wanted to see what the max length was that would work for my setup.

Another point to consider is rocker stud length. As you go longer with pushrods you reduce the number of turns for your locks and you want to maintain a minimum of about 8 turns with 7/16 studs. If you use the standard Comp or ARP 7/16 studs you will probably not get 8 turns on the lock. And as you increase the stud length you get into clearance issues with the cover. Every .10" you increase pushrod length you raise the rocker/lock about .05".

SSQATCH

While I understand that it is a balancing act to get the proper geometry I would think the shortest components would be the best (provided geometry was fine) as it removes weight from the system. Am I off base here??

Dave1980

according to what I have read, the weight on the pushrod side is not as critical as the rocker tip side.

I have my block setup with ARP sealant on the rocker studs. How the hell can I go about cleaning that out now????

Has anybody else had this problem? I am guessing that the ARP is oil soluble?

1racerdude

Ya need the geometry correct even if its 8.00PR length.
Don't worry about weight as you are not turning 10,000.
Ya need to have more thread than 8 turns with big springs for longevety

truedualws6

I had oil past the threads on 6 of 8 cylinders after 400 miles with ARP sealant. I'm aware of one other similar case, who warned me after I had already installed the heads. Since I knew I was replacing the studs I did not worry about it too much for a few hundred miles.

It was not that bad cleaning it up. I just took my time and used my gun cleaning kit patches with some brake cleaner (the stuff in the spray can). I did not just spray the threads, I soaked the patches and then swabbed the threads clean. The ARP sealant comes off really easily, which is probably why it does not do crap to stop the oil, especially with the vacuum you see on an intake port.

marshall93z

You have ported heads, or something? Why is oil in the threads an issue for you?

James Montigny

/subscribe

I'm interested to see how this turns out, although the increased distance from head to rocker has me a little concerned about flex.

truedualws6

Yes. I have Ai 185cc CNC heads with the typical hole in the intake port at each intake rocker stud. I think most ported LT1 heads have this which makes the thread sealant very important. I would imagine that the GM sealant or Permatex #2 work fine. The ARP sealant does not work.

I'm not running heavy springs or turning over 6,200 rpm so it's not a big concern. For more agressive setups you would want a custom rocker stud that has a .650" "C" dimension and a 2.00" "B" dimension based on the ARP Catalog.

truedualws6

Here is the picture of the sweep contact pattern on the #1E and #1I valve stem tips with the 7.30" pushrod. I just got back from another longer drive with the car tonight and I must say that it's definitely quieter in terms of valvetrain noise and also smoother. It's running really strong so my gut feeling is a slight performance increase. And again my wife seconds the above comments. I could make another cold idle video and compare the before and after videos. If this mid-lift adjustment is delivering more cam duration and lift to the valves then maybe it will be noticable in the idle.

wrd1972

That is about what I get using 7.150" pushrods on stock ported heads with stock length valves. If I tried 7.300" my roller would be falling off the top of the stem.

What size valves are yu using?

truedualws6

Custom manley stainless pro-flo valves 2.00" Int/1.56" Exh and I'm not sure of the length but they are longer than stock. I asked Ai once how long they were but can't find the info. With .060" spring seats I had to shim .015" to get a 1.82" installed height on the springs.