Hey guys,

Had my cylinder head off to a machine shop just to make sure it was all OK before reinstallation.
I did the head gasket, using new cylinder head bolts followed the proper torque spec and sequence - #11 bolt got the sealant - etc.
But now i am ready to reinstall my push rods into the same spots they came out of a put the rockers back on. Was gong to use assembly lube on the push rods, etc.

I keep seeing people talk about making sure each cylinder is TDC before bolting the rockers back on -
1. No idea how to do that (i get the idea of turning the engine without power - how I would have to search the form on).
2. Is this really necessary? I thought these 4.0L engines you could just reinstall the push rods and torque the rockers back down to whatever (21 ft lbs or something).

Since the cylinder head came off the block has not moved / cylinders in the same place.

Am I missing a step here if I skip over the mentioning of TDC etc.

Thanks guys,

As you can tell, as always, I'm in way over my head.

 

Put the correct size socket on the timing pulley.
Roll the engine over in a clockwise direction.

Pick up a 12" long piece of 1/4" wood dowel from the hardware store.
Put it in a sparkplug hole, when it stops moving up - viola! TDC.

 

I really appreciate your reply! Am I acheiving TDC so that I can tighten the rocker arms on or? I guess I just want to know what I am doing when TDC. I thought I was just going to tighten up the rocker arms after push rod reinstall - but then I saw a thread about doing the rocker arms at TDC or something - got confused - and now I'm asking a vague question. I lost the thread but I keep remembering something I read about at this stage of reassembly I should be doing something in TDC - but damn I just get in over my head everytime and now I'm trying to do damage control on reassembly haha. I bought assembly lube toady for hte push rods - of course there is always something else you need to buy haha. I appreciate you Mortgage Payer.

 

For anyone that comes across this thread, I found another thread on the forum that answers this up:
https://www.cherokeeforum.com/f2/rei...estions-63087/

In short:
The rockers are NON-adjustable on a stock 4.0. The valves in a 4.0L are hydraulic and thus self adjusting. Therefore you do not need to rotate the cylinders when reinstalling
just make sure you tighten everything evenly and little by little to allow for the proper seating

 

The Lifters are hydraulic and yes, the rockers are non adjustable. You would only have to torque by cylinder at TDC if you are installing adjustable roller rocker arms or if you had the head resurfaced. In the case of a resurfaced head, you would also be measuring pushrod length per lifter preload.

 

Hey Randy Bobani,

Thanks for the info. It is important because the machine shop that I sent the head to (for inspection) said they found no cracks but do say on the invoice that they performed "Valve job, resurface, crack test". The bill was $300 and they said it was in great shape - so how much resurfacing they did I don't know.

I guess I need to figure out what to do next with "measuring pushrod length per lifter preload". Is there any chance that reassembling as-is would be OK or is it just a guaranteed **** show to reassemble without these measurements.

 

If your head was in great shape then I would doubt the stock pushrods would be a problem. If the head had pitting on the sealing surface and required over .010" to be cut from the deck, then you would likely need shorter pushrods.

 

I appreciate you more than you know man. Thanks a lot for the info. I'm gunna give it a whirl as-is.
IF they are too long, what would I notice as a symptom?

 

Fact is the lifters ARE adjustable, its called preload, or setting the lash on the non adjustable valve train. It's mandatory if you have pulled the head, you really have to learn and do this, if you have it running now it's maybe still not too late. You stand a good chance of crushing a lifter or two and wearing out valve stems, and loosing all oiling to the other lifters.
Its not too hard, you just have to look it up. I can help if you want to PM me.
Many dudes have screwed this up and cant understand what went wrong when the lifters and head have to be replaced, again.
You set the preload by either counting the turns after zero lash to the 23 ft lbs, or with a micrometer, and you adjust that lash by either changing the length of the pushrods or the much easier method of adding shim washers on top of the pedastal under the rockers. Comp cams? I think thats the brand, sells the shim kits. Every non adjustable lifter engine not just the jeeps 6 is the same when it comes to this.
This has been beat to death on other threads, notably my own. However Im too lazy right now to look you up the link, but you should find it with the search function.

 

I have not started the vehicle yet. I have the valve cover gasket back on but if its critical I can take it back off.
Let me try and find your thread as I really really don't want to mess this up now.
I appreciate you and will definitely need some help here if I can't find that thread.
THANK YOU!

 

Since you're all in on getting it right the FIRST time, and promptly responded, Ill do some digging and post some threads up here. Glad you are all in bc I screwed this up with my first valve job and paid the price. Others , even 2 so called Stroker motor builders, were in the dark on it that Im aware of. One I helped through and he was also very appreciative.

 

I just changed my rockers and pushrods at 243000 miles because of wear on the pivots and rods and corresponding wear on the rockers. No need to time anything. Just cinch the bolts down to seat the rockers onto the pushrods and valves and then torque them all down to 19 In/Lbs. No particular sequence is needed when torquing. Just go 1 through 12 so you don't forget one.

 

You're referring to a form of push rod measurement via the thread pitch of the rocker bolt. Very different from an adjustment. The rockers are non adjustable and the bolts are simply torqued to 21 ft #, that of course AFTER the push rods have been measured.



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We can agree to disagree on the terminology but you are adjusting the valve lash whether you call it that or not,

 

Untrue again, the 4L features a non adjustable valvetrain that operates at zero lash. The only adjustments you can make are longer or shorter push rods, or rocker shims. There are also adjustable roller rockers available for the 4L.