#1  
Old 03-29-2023, 03:12 PM
78w72 78w72 is online now
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Default kinda urgent rocker stud ?

im helping a guy out that lives in another country and has limited english or automotive knowledge. hes trying to fix a "ticking" noise on his firebird with a pontiac 400 the prev owner rebuilt with a small XE comp cam. he asked for help on a facebook group & got all kinds of shady info from non pontiac guys, which is the norm on most those groups. they talked him into buying new comp rockers & pushrods, the stock rockers & p/r's were fine but he already bought the parts before i got involved.

got bad info for adjusting the rockers too, people were telling him how to reach zero lash by explaining to do it on all the rockers at one time in the same engine position... FB groups are terrible!

so i got him to understand how to adjust the rockers & sent a good link with instructions, the problem is he bought new ARP 7/16 studs which is a good upgrade over the stock bottleneck studs... but he bough the wrong ones for SBC that are too short, he sent me a vid showing the nuts bottom out before the rocker was even close to zero lash. so my question is this-

in an effort to save him from buying new studs (his idea) can he buy poly locks that will thread down further/far enough to get the right adjustment? or does he need the right length pontiac studs? im 99% sure he needs the right studs & i sent him a link to these no name from ebay that look to be correct for pontiac 70's D port heads, (spotts performance) then he can use the crimped nuts that came with the comp rockers or buy some cheaper polylocks if he wants to spend more $$ & wait for shipping to poland. can the shorter studs be used with polylocks or does he need the right pontiac studs. https://www.ebay.com/itm/284932549491

im hoping with the right studs & his new rockers he can eliminate the rockers being a problem, but im leaning towards the cam/lifters being/going bad since the prev owner likely didnt break it in right. he has tried adjusting the old set up a few times now & even did it with the engine running based on someones suggestion but the tick comes back or stays the same. its not too terrible but louder than what it should be.

appreciate any info on the SBC studs he has now from anyone online at the moment, he wants to get new studs ordered asap or confirm if he can possibly make the shorter studs work with a poly lock... but as i told him im pretty sure the shorter studs just dont have the thread length needed.


Last edited by 78w72; 03-29-2023 at 03:31 PM.
  #2  
Old 03-29-2023, 03:42 PM
Dragncar Dragncar is offline
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He needs BBC studs.

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Old 03-29-2023, 03:48 PM
74Grandville 74Grandville is offline
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he needs to figure out the correct rocker geometry before knowing what length studs or push rods he'll need. they make a few lengths. Depending on what type of polylock and correct geometry will dictate the correct rocker stud to buy.

I have run into this issue in the past and had to buy a different set after getting everything measured correctly.

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Old 03-29-2023, 03:56 PM
78w72 78w72 is online now
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Quote:
Originally Posted by 74Grandville View Post
he needs to figure out the correct rocker geometry before knowing what length studs or push rods he'll need. they make a few lengths. Depending on what type of polylock and correct geometry will dictate the correct rocker stud to buy.

I have run into this issue in the past and had to buy a different set after getting everything measured correctly.
Quote:
Originally Posted by Dragncar View Post
He needs BBC studs.
thanks, was pretty sure he needed new studs but he was upset he got the wrong ones since import duties are so high on top of shipping costs, he wanted to see if the SBC studs could work so i wanted to ask here first.

the pics he sent of the geometry looked decent, pretty much centered on the valve tip, the new p/r's are same length as the old ones so should keep it the same. new studs from spotts say they are same length as the stock 3/8 studs so they should work for his heads and the small cam. 100% perfect geometry may not be possible for a total amateur in another country, if its as good as it was with stock studs it should be fine with the same length 7/16 studs.

i knew the answer to this but wanted to be sure before i have him buy new studs. thanks for the help!

  #5  
Old 03-29-2023, 05:54 PM
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I know the FB group posts you are referring to and had some back and forth with him trying to determine the issue. I’m glad he was able to make contact with a single person as there were all kinds of ideas being thrown out. It was obvious he has little knowledge of the valve train and from what I saw whoever set it up initially had very little knowledge also. Of note some of the locks were of different Ypres and the locks were set at varied heights making it look like a stud had either pulled up or a cam lobe was wiped or varied length PR’s. Some of the pics appeared to indicate cam lobes had issue. I’m sure he was overwhelmed with all the crazy responses and being oversees / language barrier made it worse. Kudos to you for stepping up to try and sort it for him!!

  #6  
Old 03-29-2023, 07:17 PM
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Quote:
Originally Posted by rwfisher View Post
I know the FB group posts you are referring to and had some back and forth with him trying to determine the issue. I’m glad he was able to make contact with a single person as there were all kinds of ideas being thrown out. It was obvious he has little knowledge of the valve train and from what I saw whoever set it up initially had very little knowledge also. Of note some of the locks were of different Ypres and the locks were set at varied heights making it look like a stud had either pulled up or a cam lobe was wiped or varied length PR’s. Some of the pics appeared to indicate cam lobes had issue. I’m sure he was overwhelmed with all the crazy responses and being oversees / language barrier made it worse. Kudos to you for stepping up to try and sort it for him!!
yeah ive tried to help on a few of his posts over the last few months, i know how it is trying to work on things you dont know much about, im currently trying to restore some vintage home audio amplifiers and its tough being a beginner on the electronics & audio forums, not like automotive forums that everyone offers help & advice, so i try to help on some FB pontiac groups when i see guys like this not getting anywhere or bad advice that can cause problems. he was told to buy these ARP rocker studs by someone that didnt know what size was needed or that normal OEM BBC studs are fine for this situation. he seems like a nice guy & a real pontiac fan, hes got pontiac/firebird signs & banners all over his small garage & talks about how he & his friends all love america so much.

he sent a better vid of it running & while out driving, it sounds pretty good when hes getting on it, shifts through the gears nice with no misfires or other hesitation. hard to tell in the engine vids, but i think i see a couple rockers not moving as much as the others but hard to tell, i mentioned the possibility of bad cam/lifters but he is sure the prev owner used a good shop for the rebuild, he also knows about zddp & uses an additive so hopefully the ticking is just a bad adjustment or sloppy lifters, think he said they were the supplied comp lifters in the cam kit.

will see what happens after the new studs/rockers

  #7  
Old 03-29-2023, 08:48 PM
Schurkey Schurkey is offline
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"Small-block" rocker studs are usually (not always) 3/8 fine thread on top.

Big-block rocker studs are usually 7/16 fine thread on top.

WHAT THREAD IS ON THE POLYLOCKS HE HAS?

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Old 03-29-2023, 09:28 PM
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they are ARP 7/16, summit shows small block chevy & some fords i think.
https://www.summitracing.com/parts/ARP-134-7103

the rocker nut bottomed out on the stud before zero lash, he was asking if he could get away with using polylocks, thinking maybe they wouldn't hit the bottom of the threads as soon, i knew the answer but wanted to ask here in case anyone knew of a special rocker nut that might work he could buy for cheaper than new studs. he ordered the correct 7/16 studs and should be able to use the new crimped nuts, or will buy new polylocks.

HE ISNT USING THE PREVIOUS 3/8 POLYLOCK, HE WILL USE THE SUPPLIED COMP CRIMPED LOCK NUTS FOR NOW, OR WILL BUY NEW 7/16 POLYLOCKS

  #9  
Old 03-29-2023, 09:34 PM
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Tom Vaught Tom Vaught is offline
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Lots of Ford Higher Performance engine heads use a 7/16 stud and have longer lengths.

Summit sells most of them.

Tom V.

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Old 03-29-2023, 09:57 PM
Dragncar Dragncar is offline
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I use 351Cleveland rocker studs on my 455 HO.

  #11  
Old 03-29-2023, 11:35 PM
bluebandit bluebandit is offline
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He could also use these to get some extra length back. https://www.lethalperformance.com/ma...nt=Catch%20All
Drop a washer on top of the pivot ball and put the nut back on.

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Old 03-30-2023, 09:21 AM
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thanks for the link to the washers, those might have worked for the shorter studs he has now, but not sure there was enough thread length for the crimped nuts to grab. he already ordered the 7/16 studs from spotts on the ebay link i posted earlier so hopefully they will work right.

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Old 03-31-2023, 09:55 AM
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I had a variety of rocker studs on hand last year, various lengths, and they all had virtually the same shank (unthreaded area) length.

I bought two packs of ARP 200-8747 washers, to use between the nut and the pivot ball of the rocker. These have a 0.437 i.d. (fits nicely over a 7/16" stud) and a .875"o.d. (so it is slightly small than the pivot ball). The thickness is 0.120" which gives almost 2.5-turns more adjustment.

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Old 03-31-2023, 10:39 AM
78w72 78w72 is online now
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Quote:
Originally Posted by Lee View Post
I had a variety of rocker studs on hand last year, various lengths, and they all had virtually the same shank (unthreaded area) length.

I bought two packs of ARP 200-8747 washers, to use between the nut and the pivot ball of the rocker. These have a 0.437 i.d. (fits nicely over a 7/16" stud) and a .875"o.d. (so it is slightly small than the pivot ball). The thickness is 0.120" which gives almost 2.5-turns more adjustment.
i didnt think about suggesting washers, but he wanted to be sure he had the right studs so went ahead & bought them. but if theres a problem with the new studs i will be sure to mention the washers.

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Old 03-31-2023, 11:02 AM
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On ARP's website for rocker studs https://arp-bolts.com/kits/product.php?PL=49 it looks like the ones that would give him the most adjustment (Installed height - adjustment thread length) is about 0.900". He may want to measure what he currently has, to see if there is anything to gain with different studs.

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'67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust

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Old 03-31-2023, 11:15 AM
78w72 78w72 is online now
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Quote:
Originally Posted by Lee View Post
On ARP's website for rocker studs https://arp-bolts.com/kits/product.php?PL=49 it looks like the ones that would give him the most adjustment (Installed height - adjustment thread length) is about 0.900". He may want to measure what he currently has, to see if there is anything to gain with different studs.
he already bought the ones from the ebay link that is what spotts performance said he uses for these D port heads, probably just OEM BBC studs. he doesnt need ARP studs for this engine & already overpaid for the SBC ones he was told to buy.

OEM BBC studs should work, thats what guys have been using to upgrade the stock pontiac bottle neck studs for a long time with no issues, they should be a drop in replacement with correct thread length.

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Old 03-31-2023, 12:24 PM
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"he doesnt need ARP studs"

My point was not that he needed to buy ARP. Rather, he needs to measure. Measuring is free. I gave the ARP link because it has a lot of measurements, for comparison. 0.900" is the best of any of the ARP offerings - what do the BBC studs provide? What was the measurement for the first set of studs?

If what he is waiting on is not any different than what he has, then he has just wasted time & money. Good luck to him, I hope the parts solve his issue.

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'67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust

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  #18  
Old 03-31-2023, 04:37 PM
78w72 78w72 is online now
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Quote:
Originally Posted by Lee View Post
"he doesnt need ARP studs"

My point was not that he needed to buy ARP. Rather, he needs to measure. Measuring is free. I gave the ARP link because it has a lot of measurements, for comparison. 0.900" is the best of any of the ARP offerings - what do the BBC studs provide? What was the measurement for the first set of studs?

If what he is waiting on is not any different than what he has, then he has just wasted time & money. Good luck to him, I hope the parts solve his issue.
sorry that was my confusion on the ARP, thought the link was a suggestion to buy those.

the studs in the ebay link dont show thread length or other specs, but it does say they are the same length as the original stock studs. also says these are the right studs for most D port heads, so i hope a well known pontiac guy like spotts perf knows what will work.

the first set of studs were the stock pontiac studs, these were in the engine when he bought the car. he said there was a ticking noise and asked for help on FB, he ended up buying the sbc ARP studs i linked to first that were too short in length, the engine never ran or had the new comp rockers installed because the 1st one bottomed out on the threads before zero lash was reached. hes at a stopping point waiting for what should be the right studs for what he has, just a basic 7/16 rocker stud swap so he can use the new comp rockers he bought, ive always heard BBC rockers of that same era are a direct swap for the stock pontiac bottle neck studs. i plan to do it someday on my 78 400 6x heads that still have the stock rocker studs.

thank for the help on the sizes.

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Old 03-31-2023, 06:26 PM
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In my case I used the BBC studs on my 6X heads. They were so long that the set screws were sticking too far out the top of the poly locks. By adding the washers it raised the locks up and allowed the set screws to screw further down into the poly lock.

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