I replaced Morel hydraulic lifters with Johnson hydraulic lifters, so I needed longer pushrods to make the Johnson lifters work. Well not sure if I measured the correct size. I used Foxwells method however I had some difficulty finding the 90 degrees with the Comp Pro Magnums. It's a little harder to draw a line between the two points with the way the rocker is shaped compared to an aluminum rocker. I ended up purchasing lengths of 8.350 and 9.150. The set screws are 2 down on the ex and 4 down on the Int adjuster, is this bad? Also I have One intake that the adjuster nut only has about 5 threads engaged. Will I be ok with the set screw down showing 2 to 4 threads and what should I do about the one intake rocker adjuster with so few threads engaged? My pushrods with the Morels were Int 8.100 and Ex 8.950
Pushrod length help
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Which Morel and which Johnson lifters?
I contacted the various manufacturers to get their seat height measurements so I could know if I were to ever replace my Morels with a different one what pushrod difference there would be.
Here is the info I found (maybe this will help you out):
Morel 5374 and 4603 - 2.685"
Johnson 2112BB - 2.474"
Gaterman GP1002 - 2.618"
All measured with a 5/16” ball so the measurements are from the same reference so they are comparable.
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Don't want to side track this thread, but where did you find the seat height info? I contacted Johnson and was told they didn't have that info available. I have 2126BBR lifters on the way to replace my 4603 Morels. Thanks
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I contacted Johnson directly and they responded directly to me with the data. Funny enough, I just looked up the email, and it was on October 1st, 2020.
Almost exactly 1 year ago...
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I've used allen wrenches or a carb float ruler to find 90 deg and it seems to work great.
I did this same lifter switch out on my sbc and am much happier with Johnsons. To sanity check my measurements I used my calipers to measure the overall length of my old lifters with pushrods resting in the seat and the johnsons with same pushrods, the difference indicates how much longer the new rod should be. This only works if you know the old pushrod geometry was correct and the rockers are reused.
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
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Get a fine tip marker in white or a light color, I used a long Allen wrench and watched Scotts video 500 times 🍻Edit I also had to buy longer ARP studs but used washers stacked under my existing Brodix studs till I got my measurements correct
🍻Edit I also had to buy longer ARP studs but used washers stacked under my existing Brodix studs till I got my measurements correctI found that I screwed up on the one with the set screw way down in the adjuster, had a different mfg adjuster on it. Should the set screw be near flush? The int are about 3-4 threads and the ext 1-2. I have the Isky /Johnson 3975HYRT lifters. I shortened both a bit and the mark is on the outer 2/3 and the set screw is flush with one and about a thread down on the other.
Update, I added 2 washers measuring .140 under the int stud and 1 washer measuring .070 under the ex. Now the pushrods I ordered after doing Scott's method seem to be right if pattern on the 2/3 outboard is ok? Do I need to get longer studs or is it ok to use the washers?
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
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Longer studs! measure from the base of the stud nut or where the stud will seat on the head to the top of threads for a total height and see what base thread depth you need to, the threads that screw into head Edit before ordering anything let a Pro respond because I'm by no means a Pro just BTDT kinda guy Edit 2 poly locks flush with stud is a good thing, plenty of thread engagment
I just went through this literally 4 days ago .
In the video he draws a line with a marker but he's got a canarie yellow rocker that he's using there .Black marker works great on that but not so well on the black rocker I was using lol
I ended up running a short straight edge between center of trunion and center of roller tip and then looked to see when it was at a right angle to the valve . I can see 90 .
So I did lol
I ended up with a 2.35 arp stud .
I didn't see any studs between 1.9 and 2.35 .
The 2.35 worked
In the video he draws a line with a marker but he's got a canarie yellow rocker that he's using there .Black marker works great on that but not so well on the black rocker I was using lol
I ended up running a short straight edge between center of trunion and center of roller tip and then looked to see when it was at a right angle to the valve . I can see 90 .
I just went through the exact same thing with a 1.9 installed heighth stud and the man in the subject here ( Scott) told me to mock it up with washers in order to determine pushrod length and then get longer studs.
So I did lol
I ended up with a 2.35 arp stud .
I didn't see any studs between 1.9 and 2.35 .
The 2.35 worked
Worked on mine .
.850 is quite alot of thread .
Why the other studs you had are that much longer I don't know
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
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I have .850 in my Brodix heads, I have a set of 2" tall ARP studs for sale in classified that are for BB heads but it seems 2" are only good for stock length valves, IIRC I went with 2.350 studs, I also used Scotts designed ARP/Straub exh. rocker arms on both int. & exh. for a very good centered roller tip pattern, builder said "You know you have Exh. arms on both sides ?"
Use stud 135-7202 on the intakes (available as 2 packs part 135-7222) and 235-7203 on the exhaust. They are 2” OAL length, if that is enough for you. The exhaust studs in aftermarket heads all have the longer base thread. But, the 135-7202 say for stock aluminum heads as well. I haven’t looked close enough for another part number for the exhaust with a longer base thread.
Mack,
What heads do you have ?? I know for sure that the old GM aluminum heads need the long bottom thread to keep from braking the stud bosses on the exhaust side.
How was the wear pattern on the valves with your old lifters ? I prefer it as close to the center myself. I am not sure how you can use the mid lift method with ball pivot type rockers.
I too just went through this same thing with my build. I went from a 2'' rocker stud to a 2.35'' rocker stud. My rocker geometry was spot on, but the studs were too short to accommodate the correct rocker geometry. A wise man that frequents this forum that I consulted, said that "it was more common than not" to need longer rocker studs as a result of proper geometry and valve train set up.
I have Trick Flow 340 heads and it has the 1.3 inch base thread for ex. Bill, I have Comp Pro magnum rockers.
Matt ,what was going on when you're studs were too short?
ARP does not make a stud longer than 2 with base thread for ex, will the .850 base thread be ok for ex stud.
Matt ,what was going on when you're studs were too short?
ARP does not make a stud longer than 2 with base thread for ex, will the .850 base thread be ok for ex stud.
334-7202 will typically be OK if you need that extra length. You can buy the 235-7203 set of (8) and use a parallel ground head washer under the stud but you'd probably still have to cut the coarse threads down some. That would give you 2.100 stud length and all the length you need in the heads. I've done that before.
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