4AGE arp head studs issue?

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daveskatesallday
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4AGE arp head studs issue?

Postby daveskatesallday » Thu Aug 28, 2014 6:12 am

so I was looking into getting arp head studs but someone mentioned that one of the studs hits the distributor? also others have said it doesn't. So now i'm a bit hesitant on purchasing the head studs. Anyone that have them on here has that same issue also? or maybe the ordered the wrong studs and it interfered with the 4AG distributor?
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Re: 4AGE arp head studs issue?

Postby oldeskewltoy » Thu Aug 28, 2014 9:14 am

daveskatesallday wrote:so I was looking into getting arp head studs but someone mentioned that one of the studs hits the distributor? also others have said it doesn't. So now i'm a bit hesitant on purchasing the head studs. Anyone that have them on here has that same issue also? or maybe the ordered the wrong studs and it interfered with the 4AG distributor?


The ARP head studs need proper installation. There are 2 known issues you need to account for when deciding to use ARP head studs.

1) The stud under the distributor may come in contact with the distributor drive shaft. The reason. the ARP studs were originally designed for F/A use, F/A engines don't use distributors and so in SOME cases the distributor drive gear may interfere. Most often this is remedied by CAREFULLY grinding the distributor drive gear mount - not the actually teeth, but the base of the gear itself

2) The front exhaust side head bolt hole in the head is the oil passage from the block to the head so the cams and valves get oil. ARP studs in RARE occasions have limited oil getting to the head because of their diameter. There is a method of over drilling THAT one head bolt hole from the bottom upto the oil passage to alleviate this potential problem
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Re: 4AGE arp head studs issue?

Postby miswuevos » Thu Aug 28, 2014 9:22 am

i actually did have issues with these studs, as oldeskewltoy mentioned " The stud under the distributor may come in contact with distributor drive shaft". What we did to fix it was to simply shave off part of the dizzy just as mentioned in the following thread viewtopic.php?f=13&t=3215

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Re: 4AGE arp head studs issue?

Postby yoshimitsuspeed » Thu Aug 28, 2014 8:09 pm

Here is a writeup I did on drilling the oil passage hole.
http://www.matrixgarage.com/content/arp-oil-passage-fix

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Re: 4AGE arp head studs issue?

Postby daveskatesallday » Thu Aug 28, 2014 8:54 pm

thank you guys for the input it's very much appreciated, i hope i'll have the time to do this. I'm in a bit of a bind and really would like to put the engine together without having to stop to find out i may or may not need to grind that thing down (not a fan of downtime). I could just go with the factory head studs, my current 4AGTE was running factory bolts and never seen any issue with them, arp is nice and having extra insurance is always good but i'll just have to make my mind up. I'm not sure where the stock head bolts give, 200whp? 300-400whp?
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Re: 4AGE arp head studs issue?

Postby oldeskewltoy » Fri Aug 29, 2014 7:55 am

daveskatesallday wrote:thank you guys for the input it's very much appreciated, i hope i'll have the time to do this. I'm in a bit of a bind and really would like to put the engine together without having to stop to find out i may or may not need to grind that thing down (not a fan of downtime). I could just go with the factory head studs(bolts), my current 4AGTE was running factory bolts and never seen any issue with them, arp is nice and having extra insurance is always good but i'll just have to make my mind up. I'm not sure where the stock head bolts give, 200whp? 300-400whp?


The factory bolts are the same for the 4AGE and the 4AGZE. As I alluded too, the ARP stuff was designed for Formula Atlantic operation. One of the reasons ARP was fitted was because the engine/transmission combo in an F/A car was used as a stressed member of the chassis... the engine bolted to just behind the driver, and the rear suspension bolted to the transmission... there was no mid to rear frame, the engine trans took that load

Image

So ARP studs were used to help keep it all together....

In your case... 200hp should not be a problem.... 400 could be......
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Re: 4AGE arp head studs issue?

Postby refrwiz » Fri Aug 21, 2015 9:02 pm

I discovered the interference issue this afternoon, when I attempted to install the overhauled stock distributor into the rebuilt head. It would not go in all the way. After several attempts, I decided to take off the cam cover and could see that the ARP stud projected into the distributor shaft space. As the engine was fully assembled, I elected to cut off the distributor shaft where it projected beyond the gear. This was almost enough. I then beveled the end of the gear as I rotated the shaft. I created around 20-30 thousands clearance. The distributor fits just fine now. Rich Smirnoff
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Re: 4AGE arp head studs issue?

Postby matt dunn » Sun Aug 30, 2015 2:40 am

daveskatesallday wrote:I'm not sure where the stock head bolts give, 200whp? 300-400whp?


My setup may be a bit different as I run 7A bottom end on a 20V with a Turbo,
but I have just ditched the ARP studs and gone back to new genuine toyota studs.

We found that at about 500hp the ARP studs would let the head lift and it would push water into the overflow bottle,
and we also ran into issues on the track with similar, even went to the extent of building a 4L radiator overflow bottle,
but still had problem's.

We had previously run new genuine studs for each assembly and had never had an issue,
so last assembly we went back to the Toyota studs, and have not had any issues with then yet.

One thing I did notice in my examination of the two is the the ARP headstuds have a smaller diameter washer under them,
where the Toyota washers are larger.
Whether the weakness is in the bolt of the surface area of the washer I am not sure,
but I would not under rate how good the standard 20V studs are.
If the 16V one's are as good ther sshould be no issue with them.

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Re: 4AGE arp head studs issue?

Postby allencr » Sun Aug 30, 2015 1:27 pm

matt dunn wrote:
daveskatesallday wrote:... the ARP studs would let the head lift ...


Same torque & technique & ARP goop?
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Re: 4AGE arp head studs issue?

Postby yoshimitsuspeed » Sun Aug 30, 2015 3:20 pm

The issues with ARP head bolts have been resolved. There is one that is shorter to go under the dizzy. They also have narrower waists so you don't need to worry about the oil passage any more.
If your kit comes with the shorter bolt it should also have the narrower waist but if you want to double check the new bolts should be about 9.2mm vs the old 10mm.

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Re: 4AGE arp head studs issue?

Postby matt dunn » Sun Sep 13, 2015 1:12 am

allencr wrote:Same torque & technique & ARP goop?
Thanks.


Yes both done with appropriate technique and lube.

My dyno tuner has seen it before on 4AG based stuff,
and they ended up going to 13mm ARP headstuds ( to suit Mitsi EVO's apparantly)
to fix the issue.

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Re: 4AGE arp head studs issue?

Postby allencr » Sun Sep 13, 2015 5:40 am

Thanks.
matt dunn wrote:...appropriate technique....

Retorqued at least once and at least 10% more then factory?
Retorquing is SOP on every head, no exceptions but for that funny looking torque-to-yield stuff and using factory specs on a higher tensile fastener makes it a useless & a waste of $$.
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Re: 4AGE arp head studs issue?

Postby yoshimitsuspeed » Sun Sep 13, 2015 1:25 pm

There has to be something else going on here.
Washer diameter isn't relevant unless you are actually permanently deforming the aluminum. This seems extremely unlikely and would be very apparent when removing the bolts.
The stock bolts are 8.5mm in diameter. The ARP 20v and old 16v bolts were about 10mm. Even the new 16v design at 9.2mm is still considerably bigger. Even if the material was the same strength the holding power of the larger diameter would be very significant.
Beyond that ARP hardware is used in the highest power builds around the world and the number of reported cases like this is almost nonexistent.
There has to be something else going on that hasn't been accounted for. Unless you just happened to get that one in a hundred thousand kits that didn't get heat treated or was improperly done or something like that.
I also find it oddly suspicious when one shop has repeated issues that no one else does. Maybe they are doing something wrong. Maybe their head bolt torque wrench is out of calibration. There are a ton of variables.
I know that if I had an issue with ARP bolts the first thing I would do is send them back to ARP for inspection so I could eliminate as many of those variables as possible.

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Re: 4AGE arp head studs issue?

Postby allencr » Tue Sep 15, 2015 3:27 pm

yoshimitsuspeed wrote:Maybe their head bolt torque wrench is out of calibration.

With all the BS over accuracy & cheap & expensive & type of torque wrench & using a specific factory number, I very sincerely doubt that any HG problem has ever been caused by the torque wrench and not caused by the preparation & technique.
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Re: 4AGE arp head studs issue?

Postby SgtRauksauff » Mon Sep 28, 2015 1:52 pm

I run ARP studs in my engine, for several years, beating the pee out of it all the time. Never had a single problem. When I put it together, I read about the issue, but it was a real easy fix. I actually shortened the stud just a bit, and rounded the edges. Here it is installed, with the distributor fully inserted into the head. There's a few mm there, more than enough to avoid any rubbing:

Image

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Re: 4AGE arp head studs issue?

Postby matt dunn » Sun Oct 11, 2015 4:14 am

yoshimitsuspeed wrote:
There has to be something else going on that hasn't been accounted for. Unless you just happened to get that one in a hundred thousand kits that didn't get heat treated or was improperly done or something like that.
I also find it oddly suspicious when one shop has repeated issues that no one else does. Maybe they are doing something wrong. Maybe their head bolt torque wrench is out of calibration. There are a ton of variables.


Agree with what you are saying, just adding my experience.
The shop that I referred to is a tuning shop and did not do the build on my race motor,
it was done elsewhere.

The actual main point of my post was not to underestimate the strength and ability of the Genuine Toyota Headstuds.