Calc Sheet Measurements Needed by ARP for 1FZ Head and Main Stud Kits (1 Viewer)
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- Thread starter
- #23
I'm told there's no Cosworth kit that is M11 so, musta been something else...I wish I had a better memory, but Ford Cosworth (euro car) - seems the stud & nut kit was the right size for the 1FZ.
Not positive, don’t bank on that - mebbe search with that & see what pops up
LINUS
Waiting for the Great Pumpkin
Sorry bud, I‘m thinking some ~15yrs back - I know it was a euro car, like a Cozzie, maybe an Opel or Peogeot (sp?)
Has search popped for any of those?
I want to say @NLXTACY went down this road on one of his 1FZ’s — but again, I’m fuzzy as old as the timeline was.
- Thread starter
- #26
The Opel studs are 5.000" overall length, 1.000" thread top and bottom
The 2JZ studs are 4.500" overall length, 1.000" thread top and bottom.
I told them the 4.500" are to short and the 5.000" are too long. Theres more thread in the block than we're using with the Opel and 2JZ studs, so ARP is (paraphrasing their email) going to (in effect) add .200" of thread to the bottom of the Opel stud, so the whole stud penetrates .200" deeper, ideally giving us a stud that is also somewhat flush with the top of the nut when installed.
As explained to me, they do not modify studs by adding shank or thread length. Instead, they decide on an overall length for the application and then decide how much thread and shank is needed to make the stud usable at that overall length.
So the test studs should be the same as a stud that's 4.800” in overall length, with 1.000” of thread top and bottom. It should use more of the available block thread (so greater thread engagement) while also making sure there's not too much stud exposed above the nut.
They're going off the dimensions supplied on @mudgudgeon's calc sheet. (No pressure, though!)
The 2JZ studs are 4.500" overall length, 1.000" thread top and bottom.
I told them the 4.500" are to short and the 5.000" are too long. Theres more thread in the block than we're using with the Opel and 2JZ studs, so ARP is (paraphrasing their email) going to (in effect) add .200" of thread to the bottom of the Opel stud, so the whole stud penetrates .200" deeper, ideally giving us a stud that is also somewhat flush with the top of the nut when installed.
As explained to me, they do not modify studs by adding shank or thread length. Instead, they decide on an overall length for the application and then decide how much thread and shank is needed to make the stud usable at that overall length.
So the test studs should be the same as a stud that's 4.800” in overall length, with 1.000” of thread top and bottom. It should use more of the available block thread (so greater thread engagement) while also making sure there's not too much stud exposed above the nut.
They're going off the dimensions supplied on @mudgudgeon's calc sheet. (No pressure, though!)
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Fj80oregon
GOLD Star
How much is arp charging for this?
ARP taking their sweet time? Strange they are unable to get specs directly from Toyota and add to their lineup. Regardless, we need 1FZ head studs!!!
- Thread starter
- #31
BELATED UPDATE: Okay, measured and test-fitted the custom ARP studs. (Photos and measurements coming after I sort through the pics.) Long story short, they're ALMOST perfect. They seat completely BUT, when seated in the front under the crank gear, the clearance is only 20/thousandths. On the plus side, there's .380 of stud protruding above the nut (with washer and head gasket simulator in place). So the front two (or all) could be an eighth or even a quarter inch shorter at the top and still be good to go. Relaying this info to ARP to see what shakes out. Still hoping they'll do a ready-made set for the FZ, and that demand will justify it.
Regarding my convo with them: "we do not modify studs by
adding shank or thread length therefore adding or subtracting from
the overall length. We decide on an over all length that is required
for the job and then dictate how much thread and shank is needed to
make the stud usable at that determined length.... You said the 4.500" are to short and the 5.000" are too long. There's more thread in the block than you are using with the Opel and 2JZ studs, so we're going add .200" of thread to the bottom of the Opel stud, so the whole stud penetrates .200" deeper, ideally giving you a stud that is somewhat flush with the top of the nut when installed... The stud I am making would be the “same” as a stud 4.800” overall length with 1.000” of thread top and bottom. But we are using more thread available in the block so it adds protrusion into the block
and thread engagement while taking away exposed stud up top, which is
our end goal... I am making a stud to fit exactly the dimensions you supplied on the calc sheet."
So, that's where we are at the moment. Worst-case, the shop can shorten two studs and deburr, losing the allen-head cutouts, but I'd prefer a more elegant solution. (Because everybody sees the studs when I lift the hood.) Maybe that just means they start with a shorter stud.
Next update when I know more from ARP...
Regarding my convo with them: "we do not modify studs by
adding shank or thread length therefore adding or subtracting from
the overall length. We decide on an over all length that is required
for the job and then dictate how much thread and shank is needed to
make the stud usable at that determined length.... You said the 4.500" are to short and the 5.000" are too long. There's more thread in the block than you are using with the Opel and 2JZ studs, so we're going add .200" of thread to the bottom of the Opel stud, so the whole stud penetrates .200" deeper, ideally giving you a stud that is somewhat flush with the top of the nut when installed... The stud I am making would be the “same” as a stud 4.800” overall length with 1.000” of thread top and bottom. But we are using more thread available in the block so it adds protrusion into the block
and thread engagement while taking away exposed stud up top, which is
our end goal... I am making a stud to fit exactly the dimensions you supplied on the calc sheet."
So, that's where we are at the moment. Worst-case, the shop can shorten two studs and deburr, losing the allen-head cutouts, but I'd prefer a more elegant solution. (Because everybody sees the studs when I lift the hood.) Maybe that just means they start with a shorter stud.
Next update when I know more from ARP...
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- Thread starter
- #32
BONUS UPDATE: Going to ARP main studs, which fit PERFECTLY, couldn't be better. Test-fit below during teardown. From ARP: "Main Studs/Bolts: The 203-4205 JZ kit should work for main studs. The bolts from kit 207-3900 (4G63) should work for a bolt option."
I need to confirm that what I have here are the 203-4205 JZ studs, and will post when I find out.
I need to confirm that what I have here are the 203-4205 JZ studs, and will post when I find out.
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How does everyone see the stud when you lift the hood? Clear valve cover?
- Thread starter
- #34
OCD joke that may have gone astray.
203-4205 Have been used as Mains before. Just make sure you check your oil pan clearance some have cracked oil pans d/t lack of clearance.
- Thread starter
- #36
Will check that, thank you. The donor pan is dented as well.
Glad this is still in the works. I’d shorten the front two the least amount possible, if an 1/8 is plenty, that’s all she needs. I like to see a little thread stick out… my OCD 
I'd like to see this stud along side a factory bolt and an opel stud.
- Thread starter
- #39
Ha, thanks! Passed your tip on to the machinist, who test-fitted and said five of the studs won't clear the pan. Not sure which P/N I have here, will check. Here's a test-fit main stud, and a few of the stock bolts in place. I guess things get pretty tight...
It’s unbelievable that they would have designed the pan with that tight of tolerance… it’s an oil pan for crying out loud… maybe they tried to make it double as a windage tray
