Can anyone explain why ARP head studs for 1hd-t so expensive???
ARP head studs (1 Viewer)
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Comparing them to other diesels shows they're comparable.
$775 us for a set of head studs is pretty normal.
Cummins head studs run 450-1100 depending on tensile strength.
500-700 for Duramax.
500-1200 for a powerstroke.
And the 1hdt isn't exactly common.
They're a custom stud, the IP (so to speak) of which is owned by a the companies in Oz that stock them. There's demand for them, so they can more or less name their price, and they have to factor in shipping, exchange rate and all that. Remember that in Australia and NZ there are heaps of 1HDT engines. Even in my street there are 4 1HD/F/T 80s and in my wider neck of the woods there's heap too. NZ and Oz to a lesser extent went absolutely nuts for Japanese imports in the early 90s when the tariffs were removed.
Vehicle modification rules both sides of the Tasman mean that if people are chasing power the 1H series engines are worth it, sure you'd probably get more power (granted the torque is different) out of an LS swap but that triggers all sorts of certification and engineering check shenanigans. Here in NZ its at least $1000 to even have an engine swap looked at, let alone signed off. It's not impossible and its been done but it's definately and extra step/mess around.
Plus stuff in general is just more expensive down under. Cost of living is pretty high in both places at the moment.
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I can partly answer this question as I have been stocking and re-selling the ARP head studs for the 1HZ and 1HDT for a while now, and have recently started with the studs for the 1HD-FT and 1HD-FTE (also sold as the Yanmar 6LPA which is based on the 1HD-FT engine). I have a hard time keeping these in stock as I can only get small numbers in, and then they sell almost immediately.
The exclusive rights to these studs is owned by one of the main engine parts suppliers in Australia, Engine Australia. These studs are somewhat more expensive than for other diesel engines, but not by a huge amount. This is most likely related to the limited production runs and the cost of commissioning the development of a new product, and then of course shipping and importation costs.
The studs are ARP 2000 material and are made in (small) production runs based on demand. The demand for these kits has been higher than expected, and then there has been supply chain issues (as with everything these days) and then also losses of inventory due to the catastrophic flooding in Australia. The flooding has not affected the price, but it did wipe out a whole shipment of head studs at the start of this year.
The studs are available in two configurations: the 11mm drop in head stud kits and the 1/2" machine fit kits where the block is drilled and tapped for 1/2" threading and the head bolt holes in the head are opened up to fit the larger diameter stud.
The 11mm head studs offer about 40% improved clamping force when compared to the stock TTY head bolts when using the torque procedure supplied with the studs. The stock torque method is not used, and should not be used as it is specific to TTY bolts.
The ARP studs can be re-used. This is a big advantage if you're taking your head off from time to time.
The 1/2" ARP 2000 head studs are less costly than the 11mm versions, but the downside is that the the block and head need to be machined. The upside is that these are stronger than the 11mm versions and if you're looking for the ultimate in preventing head lift because you're running high boost numbers - like in the mid 40 PSI range - then these are the ones for you on your next engine build.
The Engine Australia part numbers are:
11mm drop in fit - 1HZ 1HD-T = HSKTO340A
11 mm drop in fit for - 1HD-FT, 1HD-FTE, Yanmar 6LPA = HSKTO30A
1/2" machine in fit - 1HZ 1HD-T = HSKTO340
1/2" machine in fit - 1HD-FT, 1HD-FTE, Yanmar 6LPA = HSKTO360
Note that ARP does not sell these to the retail public or to wholesale business customers, they are exclusive to Engine Australia. You can get them from busineses such as mine (located in Canada) or others that are located in Australia or New Zealand.
I am adding to my performance parts listings slowly and steadily as there are requests for these items to be stocked. I have recently brought in a few sets of the ACL Race Series main bearings to compliment the ACL Race Series con rod bearings that have become increasingly popular - the Main Bearings will appear on my new eCom site soon.
For those looking for more performance, I am also waiting for stock to arrive for the new 4340 I-Beam Billet Connecting Rods which are replacing the now discontinued H-Beam Connecting Rods for the 1Hx series of engines. I should be seeing stock of these at some point in late June or early July 2022. Pre-orders will be accepted soon, stock is fairly limited. These pair nicely with the pre-topped ceramic coated pistons...
~John
The exclusive rights to these studs is owned by one of the main engine parts suppliers in Australia, Engine Australia. These studs are somewhat more expensive than for other diesel engines, but not by a huge amount. This is most likely related to the limited production runs and the cost of commissioning the development of a new product, and then of course shipping and importation costs.
The studs are ARP 2000 material and are made in (small) production runs based on demand. The demand for these kits has been higher than expected, and then there has been supply chain issues (as with everything these days) and then also losses of inventory due to the catastrophic flooding in Australia. The flooding has not affected the price, but it did wipe out a whole shipment of head studs at the start of this year.
The studs are available in two configurations: the 11mm drop in head stud kits and the 1/2" machine fit kits where the block is drilled and tapped for 1/2" threading and the head bolt holes in the head are opened up to fit the larger diameter stud.
The 11mm head studs offer about 40% improved clamping force when compared to the stock TTY head bolts when using the torque procedure supplied with the studs. The stock torque method is not used, and should not be used as it is specific to TTY bolts.
The ARP studs can be re-used. This is a big advantage if you're taking your head off from time to time.
The 1/2" ARP 2000 head studs are less costly than the 11mm versions, but the downside is that the the block and head need to be machined. The upside is that these are stronger than the 11mm versions and if you're looking for the ultimate in preventing head lift because you're running high boost numbers - like in the mid 40 PSI range - then these are the ones for you on your next engine build.
The Engine Australia part numbers are:
11mm drop in fit - 1HZ 1HD-T = HSKTO340A
11 mm drop in fit for - 1HD-FT, 1HD-FTE, Yanmar 6LPA = HSKTO30A
1/2" machine in fit - 1HZ 1HD-T = HSKTO340
1/2" machine in fit - 1HD-FT, 1HD-FTE, Yanmar 6LPA = HSKTO360
Note that ARP does not sell these to the retail public or to wholesale business customers, they are exclusive to Engine Australia. You can get them from busineses such as mine (located in Canada) or others that are located in Australia or New Zealand.
I am adding to my performance parts listings slowly and steadily as there are requests for these items to be stocked. I have recently brought in a few sets of the ACL Race Series main bearings to compliment the ACL Race Series con rod bearings that have become increasingly popular - the Main Bearings will appear on my new eCom site soon.
For those looking for more performance, I am also waiting for stock to arrive for the new 4340 I-Beam Billet Connecting Rods which are replacing the now discontinued H-Beam Connecting Rods for the 1Hx series of engines. I should be seeing stock of these at some point in late June or early July 2022. Pre-orders will be accepted soon, stock is fairly limited. These pair nicely with the pre-topped ceramic coated pistons...
~John
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I have suspected stripped a couple threads on my 1hz. In measuring it up for thread repair, i see the threads start 10mm below the block face. Given there is 30mm of bolt hanging below the head that puts only 20mm of grip. I was hoping to increase that with coils but the hole starts at 13mm reducing to the 11mm thread. Holaia 40mm deep tho so there is yet 10mm of thread to be had if there were longer bolts made. Of course these arp studs use that extra depth up, very cleverly, and the main reason i would buy them. If i had a grand....
So researching.. discovered subaru use 11mmx1.25 as well and they run looong bolts. 173mm on some and 190mm elsewhere. Both too long. However, they also run that 64mm of thread where we ony need 30mm to fill the holes thread up catching the extra 10mm our bolts miss. So simply cutting 30mm off the subaru 173mm gives 143mm which is 10mm longer than the 133mm of the 1HZ bolts. That creates an ARP variant for studs but also allows a stock bolt that just reaches further. Ordering some now!
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FYI, we are now having FTE heads machined under the cam for the head bolt seats. We are taking off 2mm since the ARPs don't clear under the cam, rather than modify the studs we just remove a little off the seats. This is only an issue for studs under the cam.
Cheers
Cheers
Is there any particular part we should order do they can fit?
Does that mean all HSKTO30A have to be ground down a bit?
Can you please explain what Pre-topped pistons means? Are the piston tops machined down to lower comp ratio?
Thanks
It's to lower piston height to accommodate block machine work. But will also lower compression
Gotcha. That's what I was wondering. How much are they topped? Getting ready to tear an engine down and measure everything soon.
Depends. Google search says .15mm for a 1hdt engine
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All the 24v ARP kits we have gotten are the same. I don’t recall exactly because it has been four or five FT/FTE engines ago but on the first kit we noticed problems with cam lobes and stud clearance. We ground the studs under the cam on that one but all the rest have had the seats under the cam machined down 2mm.
Cheers
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Sorry, I don’t login to to ‘Mud very often as business and life is far too busy for me.
Pre-topped pistons have a few thou taken off the top at the manufacturer/supplier level to allow for either a coating such as ceramic or anodizing (for piston crown heat control), or when the block has been decked to make it flat again and to keep piston protrusions within acceptable tolerance.
There are other ways of correcting block and cylinder head spacing/stack height relationships: head gasket shims, and an aftermarket (Cometic) grade 7 head gasket (yes, I did say grade 7).
1HZ, 1HDT Performance Head Gasket - Toyota Gr. 7 - GHPTO350G7 - https://www.shopraddcruisers.ca/1hz-1hdt-head-gasket-gr-7-ghpto350g7.html
John
