4.0 Head bolt stud thread and pitch on manifold side?

I'm putting the engine hoist on the 4.0 tomorrow and plan on lifting by two of the head bolt studs on the manifold side. I took the nut off the rear stud near the firewall (the one with the grounding strap attached) to get the right nuts, but the parts guy gave me M10 X 1.5 nuts and I picked up M10 washers which don't even fit over the stud, so these can't be the right size.

So what size do I need? FSM didn't help me unless I missed it somewhere?

I'm using 2 attachment points on the distributor side too so no need to :flame:

Thanks guys,

Jonathan

Should be 7/16-14, I believe.

Re: Re: 4.0 Head bolt stud thread and pitch on manifold side?

kastein said:

Should be 7/16-14, I believe.

Click to expand...

This is correct, just went and checked.

Jonner said:

I'm putting the engine hoist on the 4.0 tomorrow and plan on lifting by two of the head bolt studs on the manifold side. I took the nut off the rear stud near the firewall (the one with the grounding strap attached) to get the right nuts, but the parts guy gave me M10 X 1.5 nuts and I picked up M10 washers which don't even fit over the stud, so these can't be the right size.

So what size do I need? FSM didn't help me unless I missed it somewhere?

I'm using 2 attachment points on the distributor side too so no need to :flame:

Thanks guys,

Jonathan

Click to expand...

The manifold screws are threaded 3/8"-16UNC, should be about 1.25" long.

The manifold studs are threaded 3/8"-16UNC into the head, and the end that takes a nut should be 3/8"-24UNF.

The studs should be replaced while you've got the manifolds off, as well as the rest of the hardware. I use silicon-bronze or aluminum-bronze for the screws (3/8"-16x1.25"UNC HHCS) from Fastenal for the screw replacements, I can pick up 3/8"-16 brass threaded rod (cut three, 2" long, and dress the ends) for the studs and 3/8"-16 marine brass hex nuts for the collector studs.

Why? Because brass won't seize against iron or steel, AND it will get incrementally stronger with head-cycling (instead of incrementally weaker, as iron/steel will.)

For retention, I'll use a rounded-off punch in a V-block to deform a single thread about 3 threads up from the tip. This will work better than LocTite, although there is a grade that will work with exhaust heat (#277, I think,) but deformed threads will work better. The studs may be similarly retained, but that's a bit more difficult to install them, since you have to make sure to "double-nut" them properly to get them screwed in. They may also be staked at the surface of the casting, but I don't recommend this, because if you slip you'll bruise the sealing surface.

Nuts may be deformed similarly using a rounded-off cold chisel on ONE side of the nut, and thread the clean threads on first.

(With deformed threads, elastic deformation and interference will retain the fastener, and it will stay put unless it gets hot enough to melt.)

Cuprous hardware may be re-annealed by heating and quenching (opposite of steel,) I throw the hardware into the oven on full head (500*F) for an hour then throw them in the water. Leave them there for about five minutes, pull them out, and install. They'll dry in use, and they won't rust anyhow.

I thought he was talking about the manifold studs too at first but he's talking about the threaded top end of the driver side head bolts on OBD2 (or all HO? or all including RENIX? I forget) 4.0 engines.

It looks like I should of worded my question a little clearer but I was talking about the head studs on the TOP SIDE of the motor. I wanted to use the strongest looking fasteners to hoist the engine and the head studs looked the strongest.

5-90 thanks for the detailed explanation on the manifold bolts though. You made some detailed engineering considerations I've never even heard of before... Feeling smarter now!

So, to be clear here, my 98 HO 4.0l has 7/16-14 studs sticking out of the top side of the engine. Thanks Kastein and Don!

I got the motor pulled today, thanks guys!

kastein said:

I thought he was talking about the manifold studs too at first but he's talking about the threaded top end of the driver side head bolts on OBD2 (or all HO? or all including RENIX? I forget) 4.0 engines.

Click to expand...

Oops. Yeah, I think I slipped...

The "stud tops" on my RENIX are threaded 7/16"-14UNC. For my part, I'd just remove the head and use the 1/2"-13 screw holes to pull the block. The head may be pulled as a unit, with care (remove the valve cover, remove the rockers, and use the foremost and rearmost hole for best results. The manifolds may remain undisturbed until you get it on the bench, which makes servicing that gasket easier. The head may also be installed as an assembly, just watch your fingers! )

Most hoists, as far as I know, use 1/2" proof coil chain. I tend to use fender washers (the big ones) under the nuts to retain if going directly through the link, or under nuts smaller than 1/2" nominal thread if you have a chain with steel tabs on it instead. (I'm paranoid. I also haven't broken my feet. You decide.)

You said you got the job done - so take from this what you need, and leave the rest for the next guy...

Jonner - I have to pull and install more than one of these and I am planning to attach to those head studs as well. Did the engine sit pretty straight doing that? Which two studs did you use? I need it balanced and was considering attaching one end of the chain to one of the A/C compressor bolts for better balance but would prefer the head studs. Thanks

Mealticket said:

Jonner - I have to pull and install more than one of these and I am planning to attach to those head studs as well. Did the engine sit pretty straight doing that? Which two studs did you use? I need it balanced and was considering attaching one end of the chain to one of the A/C compressor bolts for better balance but would prefer the head studs. Thanks

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You should be able to see where I mounted the hoist from the pictures below, but on the exhaust manifold side, top of the engine, I used the 2nd and 3rd rear most head studs. On the distributor side of the engine, I used both top AC bracket bolt holes. I had to use some threaded links to allow me to hook the L-brackets from the load leveler onto the AC bracket side to get everything to fit where I wanted it.

To get everything straight and level I purchased a load leveler from Harbor Freight which I would HIGHLY recommend. It made adjusting everything a lot easier and took the stress out of maneuvering the whole thing away from the transmission, out of the Jeep, onto the engine stand, off the engine stand, and into the back of my dad's truck.

Hope that helps!

Thanks so much for taking the time to put up these pix, Jonner! That's a major 'solid'. Wow; I didn't think about using two studs and a load leveler. I was going to use a stock lifting eye from another car but it would have to be routed out a bit to slide over the 7/16 stud. I have a sweet bracket off of a Toyota for that A/C bolt attachment. I actually have a load leveler; got dig it out. Thanks so much,

Mealticket

Glad to pay the community back, so no problem. I've gotten so much good advice on here, it's time for me to contribute some of that back.

I bought the load leveler thinking if I don 't use it, I'll take it back. It turned out to be totally worth it. Pick up some big fender washers if you are looping straight thru some chain links or closeable links too.

If you're doing a few of these engines, a floor jack attachment for a tranny jack or a real tranny jack would have been helpful. If you have the funds I recommend picking one up, and then you can resell it after your done. I wish I had one, and opted for a wide assortment on 12" long wood blocks to angle the tranny where I needed it since I had everything disconnected already. I opted to leave the tranny resting under the jeep to simplify reinstallation but you can do what's right for you.

Happy motor pulling Enjoy!

Jonner said:

I'm putting the engine hoist on the 4.0 tomorrow and plan on lifting by two of the head bolt studs on the manifold side. I took the nut off the rear stud near the firewall (the one with the grounding strap attached) to get the right nuts, but the parts guy gave me M10 X 1.5 nuts and I picked up M10 washers which don't even fit over the stud, so these can't be the right size.

So what size do I need? FSM didn't help me unless I missed it somewhere?

I'm using 2 attachment points on the distributor side too so no need to :flame:

Thanks guys,

Jonathan

Click to expand...

Just went to get one today for my ground strap, it's an M12 1.50. Oooops too late of an answer. My size was for a 1996 XJ.