ARP head studs

[The Mutt]

Does anyone know the P/N for a set of ARP head studs? blew the head gasket this afternoon.

While I'm at it, is Rocket Industries the best spot to get them from in the Sydney area?

Glenn

[p38arover]

Do they make a set for the Isuzu?

[The Mutt]

ARP head studs going into the 4BD1 has been mentioned in other threads, length and diameter is all you would be looking at, if I had the head off already I would take one of the old bolts in and get a set to match, I'm trying to get a head start buying the bits needed before pulling the motor apart this weekend.

Glenn

[DRanged]

Glenn

Mate took me a while to find it on my business system I can tell you.
I only have the numbers for the studs but they should be able to source the nuts for you. I got then from Fabre Aust in Sydney.

ARP-AU5.600-2lb 14 off

ARP-AU4.950-2B 4 off

Make sure you run a bottoming thread tap into your block and make sure all the rubbish is out as the studs need to seat properly in the block. (I will do this next time).

There not cheap but are a great bit of kit.

Good luck Justin

PS pls post up the p/n for the nuts when you get them.

[Bush65]

I have fitted ARP studs in my 4BD1T. I got them through Fabre, but they had to come from the USA. They were stock studs and nuts, but may not have been listed for an Isuzu 4BD1.

I have posted the part numbers, and will check and edit my post here when I find them.

Three studs protruded too far and I had to counter drill the holes in the block to sink the studs lower, then run a tap down to remove any burrs from counter drilling. The top of the studs have allen key sockets, so I didn't want to shorten them.

Two of the studs are under #2 and #3 injectors - the holes at #1 and #4 are already counterbored for dowels and didn't need more.

The third was at the front post for the rocker shaft. An alternative would be to remove part of the boss on the rocker post.

One of the head studs is used to bolt down the support bracket for the inlet manifold and fuel filter. I didn't get a special bolt for here, and just cut the support bracket to clear the new ARP stud. I'm not using the stock fuel filter, but IMHO the bracket should have enough bolts without using the head stud.

Edit:
14 studs part number ARP-AU5.600-2LB
4 studs part number ARP-AU4.950-2B
2 packs 12 point nuts part number ARP300-8338
2 packs washers part number ARP200-8536

[Bush65]

Glenn,
AFAIK the head gasket and head bolts are the same for both the 4BD1 and 4BD1T, but I stand to be corrected.

What is different between them is the procedure for tightening the head bolts.

IMHO if you do not intend to run turbo boost pressure over about 30 psi, then stick with genuine Isuzu head gasket and bolts, but use the 4BD1T head bolt tightening procedure.

If running boost pressure between 25 and 30 psi, I would modify the tightening procedure. Also make sure the block and head surface are both thoroughly clean and free of any oil, grease or fingerprints.

The genuine Isuzu 4BD1T head gasket is a MLS (Multi Layer Steel) type and with stock bolts is known to hold ok with 40 psi boost pressure, but blow with over 60 psi.

[The Mutt]

How many people are running over 30psi:o

Our motor was originally a 4BD1, I have added the turbo and intercooler myself, I thought I was doing well getting 17 psi.

I am trying to setup the vehicle as a tow vehicle for our sailboat, approx 2 ton loaded on trailer, I don't want to be in a situation where I have to plod along at 40k's hr uphill because the turbo is getting too hot, that's what happened prior to the intercooler install.

So from what you are saying and how I am setting up the vehicle, I don't need to go with the ARP studs, but, if I go with the factory bolts should I get a new set or replace them with new ones.

The head won't come off till Monday now, the gasket that I ordered through Gilbert @ Roach didn't arrive from Vic, they forgot to put it on the truck, no worries, I'll do the BAS statements then start fitting the York compressor to the right side of the motor, I'll also change over the gaskets for the front timing plate and reseal the sump gasket.

B!*@@$ oil leaks, I told the outlaws that I was putting the oil back where it came from.

Glenn

[The Mutt]

AFAIK the head gasket and head bolts are the same for both the 4BD1 and 4BD1T, but I stand to be corrected.

What is different between them is the procedure for tightening the head bolts..

Sorry to be a pain, I have the Zenith workshop manual for the 4BD1, there is only have one way mentioned to put the head back on.

1st step 50.6 lb.ft
do up in this order

the 4 rear bolts starting over inlet side 4th from engine front
followed by the 4 front bolts starting over exhaust port 1st from engine front
followed by the 4 bolts starting over inlet side 3rd from engine front
followed by the 4 bolts starting over exhaust port 2nd from engine front
finishing with with the middle most bolt.

2nd 65.1 lb.ft
repeat order above

3rd 90lb.ft
repeat order above

This pattern and torque settings are for turbo and non-turbo, what info is lacking in my manula that you know of.

Glenn

[isuzurover]

Sorry to be a pain, I have the Zenith workshop manual for the 4BD1, there is only have one way mentioned to put the head back on.

1st step 50.6 lb.ft
do up in this order

the 4 rear bolts starting over inlet side 4th from engine front
followed by the 4 front bolts starting over exhaust port 1st from engine front
followed by the 4 bolts starting over inlet side 3rd from engine front
followed by the 4 bolts starting over exhaust port 2nd from engine front
finishing with with the middle most bolt.

2nd 65.1 lb.ft
repeat order above

3rd 90lb.ft
repeat order above

This pattern and torque settings are for turbo and non-turbo, what info is lacking in my manula that you know of.

Glenn

My manual (September 1988 ISUZU WS manual) says that 1987 and newer 4BD1, 4BE1, and all 4BD1T should be tightened as follows:

Step 1 : 50 lb.ft
Step 2 : 65 lb.ft
Step 3 : 90-120 DEGREES

Starting at the central bolt under the tappet cover, and working in anticlockwise circles of increasing diameter.

[Bush65]

Not sure about re-using head bolts. Ideally you would though.

Further to what Ben has posted on tigtening:

Use moly disulphide grease to lubricate the threads and underside of bolt heads.

Tighten as per Ben's post. This pic might help with the sequence.

[The Mutt]

I'm glad I posted the tightening settings from my manual, I had to get out a magnifying glass to see the degrees sign after the 90.

I already have the Moly out for the threads, knew that one, thanks for mentioning it though.

The FORWARD in my manual says "applicable to 1986 and later models" tightening in the reverse order to Ben's pic, I'll tighten from centre out assuming a 1982 motor should be treated the same as a 1987 model and newer.

Glenn

[Bush65]

...tightening in the reverse order to Ben's pic, I'll tighten from centre out assuming a 1982 motor should be treated the same as a 1987 model and newer.

Glenn
In general (not just for heads), the tightening pattern should start from the stiffest part and extend toward parts of lesser stiffness.

99.999% of the time this will be from centre out to furthest ends.

If the end bolts are pulled down 1st, their clamping force combined with friction will restrain the centre ever so slightly and increase its stiffness, enough that it is highly likely that the bolts near the centre will not be able to develop the same clamping force on the gasket.

[clubagreenie]

Looking at the second last post on the first page if you need to final tension to a degree angle then they are probably TTY (torque to yield) and so should be replaced every change.

One IMPORTANT thing with ARP, run at least 3 pref 5 torque sequences to stretch them. They don't distort but it is the recommended preparation. Also use moly gease as the lube not oil it won't hold under the pressures created. The ARP lube (read expensive) is just this anyway.

And also check the tensions after torquing as as stated earlier the inners could be looser post full tension. Don't loosen just test again with tension wrench.

[THE 109]

When torquing up main caps and big ends on large caterpillar engines they are done to a setting,then angle turned an extra so many degrees.They don't require the bolts to be replaced everytime so I'm wondering why you would on an isuzu?
Cheers Eric

[Bush65]

A lot of people assume that bolts tightened by a angle of turn method are reaching yield, but it is not necessarily true.

I haven't conducted any tests to see one way or the other what is happening with the Isuzu head bolts. It depends on more factors than thread pitch and tightening angle - for example while the bolt is stretching under tension, the head is compressing and how much depends upon the height through the head and thickness/distribution of material around the bolt hole.

A reasonable test would be to accurately measure the bolt length before and after it has been in use to determine if permanent stretch has occurred. Cummins supply gauges for checking some of their bolts and they allow them to be re-used unless the permanent stretch makes the bolt length exceed the gauge length.

Edit: I had a careful look through the cylinder head section of my manual, and they give a host of measurements/inspection instruction for many of the components, but no mention of head bolts with regard to inspection or discard/replacement.

[isuzurover]

Edit: I had a careful look through the cylinder head section of my manual, and they give a host of measurements/inspection instruction for many of the components, but no mention of head bolts with regard to inspection or discard/replacement.

My manual has 2 different torque settings for "new" and "reused" head bolts for the pre-1987 method.