Getting ready to change out a cracked 0331

[md21722]

Re: Getting read to change out a cracked 0331

I have two more questions:

1. I haven't pulled the head on a push rod engine before. Factory manual says to tighten the rocker arm bridge bolts one turn at a time, alternating so as not to damage the rocker bridges. Is it necessary or recommended to also turn the crank? Is the factory manual overcautious on one turn at a time?

2. If you don't have an engine hoist, what's the best way to get the old head off the engine and the new one on? One of the YouTube videos shows a guy sitting on the front clip/support and lifting one out and the new one back on. If the engine hoist is used, what's the best way to secure the head to the engine hoist? Some engines have mount points for this, but the Jeep head does not. Here's what I came up with- temporarily move the front exhaust manifold stud to the A/C bracket area (they take the same size), attach chain, and secure with exhaust manifold stud nuts. I rather not buy an engine hoist just for this. I sold the last one I bought because I hadn't used it in 10 years.

 

[Talyn]

Re: Getting read to change out a cracked 0331

The thing with the rocker arms is that they are connected buy a bridge. If one lifter was on the nose of the cam (valve open) and the other was on the base (valve closed), tightening the closed valve first could bend the bridge. It will be noticeable when you install the rockers when it is open. If both valves are closed it won't be an issue. Rotating the engine by hand will aid in this as you should be bringing the pistons up to TDC on the compression stork where both valves will be closed.

Get a friend to help you lift it off.. its big and heavy. You do have to be careful installing the head as not to damage the gasket.

 

[Tony_SS]

Re: Getting read to change out a cracked 0331

I managed to wrestle the head off moving one side at a time. I put cardboard on my fenders and header panel and just wreslted it up there. Not a big deal, but def. awkward.

The UPS lady had a hell of a time dropping of my J&C reman head LOLOL

 

[md21722]

Re: Getting read to change out a cracked 0331

Hey all,

Pulled the head today. I used the brute force method to get it out of the engine bay.

A couple of questions/observations:

1. Is it normal for the rocker arm bridges to twist? I removed the pivots and straightened the bridges out by eye. Should I be good here?

2. Three of my head bolts were rusty. The ones on the passenger side around cyls 3-4. Is this ever normal or is it related to the head crack?

3. I was surprised that the entire head gasket came off stuck to the head. The block deck will need very little cleanup. Same with the manifolds. Is this pretty common, did I get lucky?

4. With the dowel pins in the head does it really help to make dowels when putting the new head on?

5. I couldn't find any traces of thread sealer on the front drivers side bolt. But it was dry. It actually looked like there was some sealer on the next bolt. I'm guessing whoever pulled the head before missed this or mixed up the bolts.

6. Head gasket looked perfect.

I plan to finish cleaning gasket surfaces and parts and get it all back together tomorrow.

Thanks again for the help!

 

[Talyn]

Re: Getting read to change out a cracked 0331

1) It happens, mostly from too much torque no the bolts or using an impact on them. Just make sure the rocker tip is centered on the valve stem when you reinstall.
2) They shouldn't be unless it was just residual moisture.
3) It varies. Use a gaskets scraper to clean the surfaces. Not one of those POS discs on a die grinder.
4) It may help since you are muscling it on. This goes back to the don't damage the gasket. However, it might be hard to do with the limited room in the back though.
5) Even if they mixed up the bolts they still should have put new sealer. Since the head was pulled prior and the head bolts were already reused once you will want to replace them.

 

[md21722]

Thanks. Head is on and torqued, valvetrain on and torqued, valve cover and spark plugs. I didn't try making dowels out of head bolts or threaded stock. Now I'm on to putting everything else back together.

 

[Talyn]

I did the head with out a hoist once... it was the first and last time.

 

[md21722]

Got everything back together last night. Jeep seems to run well.
Thanks all!

 

[Talyn]

Glad it went well!

 

[md21722]

I was looking at my old head and noticed that 4 valve stem seals were riding high on the valve stem. I don't know what was going on with that!


A valve train question - the push rods were pretty varnished. I wiped them down with a rag which got some off and then hit them with brake cleaner to get more off. The rocker arms were a bit gummy around the bridges. I'm new to push rod engines, in the past my OHC engines were always clean. Does it make sense to change the push rods? I am wondering if the insides are a bit varnished restricting oil flow to the top. Or if this is normal in this engine, i.e. no oiler, only push rods bring oil to top end. And, if so, what about the rockers? Can you change only the push rods? I noticed that JEGS sells a Crown Automotive "Rocker Arm Kit" for $80 that includes new rocker arms, pivots, and bridges. The dealer charges $3.50 for a pushrod and $28.75 for a rocker. AutoZone sells Melling push rods for $2.69 and Melling rockers for $6.59. Are Crown or Melling good brands or would I want to stick to dealer?

 

[Talyn]

Changing parts because they are varnished is a waste of money. You can look through the push rod and see if there is a problem inside. Chances are not.

 

[N8N_99xj]

Melling is a respected brand, not sure about Crown, no aspersions cast but the only products I've used of theirs were some stock replacement rear shackles. The price was "too cheap to be good" but they fit fine. Not enough miles on them to comment on durability, but the bushings haven't disintegrated yet.

 

[winterbeater]

Sounds like you didn't change the lifters. They are the critical part. Just clean up the rest the best you can. Carb cleaner on the insides, etc.

 

[md21722]

Hey all,

I talked to the machine shop about the old head with its dislodged valve stem seals and they said they see it quite a bit and attribute it to age and said that overheating helps that along.

I took another compression test with the new head.

This time I got 161,161,145,147,162,161.

When I did the compression test before the head I left the fuel pump relay in, but this time I took it out.

 

[md21722]

I have two more questions,

1. I took the valves, springs, and valve stem seals off the old head. How tight should valve stem seals fit? These ones came off very easily which probably explains why many of them had moved from where they were supposed to be.

2. What should I do with the old head?

Thanks,
Brian

 

[Talyn]

They should be fairly tight, but not extremely hard to take off.

Recycle the head. Or use it for a boat anchor. Or use it to mock something up. Or make a lamp out of it.