Rocker arm falling off

[135sohc]

Last week going into work pulling away from the light I got to around 40 and shifting into 5th all hell broke loose. Like someone flipped a switch the car just instantly fell on its face and ran super rough. Ultimately after making it home that night I pulled the valve cover and found after zero compression that the rocker arm on cylinder 4 intake valve fell off and the valve was hung open. lightly tapped on the valve stem and the valve popped right back up. Yesterday I took the spring and seal off and found nothing abnormal, no excesssive endplay, valve was smooth and not even a hint of binding. This head has the aftermarket valve guides with the circlip so they dont fall supposedly. Valve fully closes so the seat is ok. just a random freak occurance ? Put it back together last night and everything has been ok so far.

[tryingbe]

Could be a bad lifter.

[Vigo]

Seems like the most common cause is a valve seat falling partially out.

[ajakeski]

This caused a rocker to pop off on the engine in a Daytona I parted out. A chunk of the piston got caught between the valve and seat.

[bfarroo]

I've had them pop off on two different cars, both cars I couldn't really see anything wrong so I loosened up the cam a little and slid it back in and both cars ran for years after that without another issue. I'd check that the rocker isn't damages, the lifter isn't soft and the valve moves freely and if so put it back in and run it.

[GLHS60]

Agreed on the strong possibility of a dropped seat, seen it many times. Pops back into place and will be fine for an hour or a week?? Sometimes happens a few times before getting jammed between the valve and head.

Thanks
Randy

[4 l-bodies]

Could also be a very slightly bent valve stem. Sometimes during disassembly (depending on the type of valve spring compressor your using) The valve keepers don't want to release off of groove after valve spring is compressed. Disassemblers will then smack valve head with rubber mallet to get them to release. You can actually bend the valve stem that way. Valve stem can also bend from high exhaust temps (ask the Masi 16V owners about this). Valve stem could have been easily nicked esp. if cleaned by tumbler machine. Could also be the ID of guide is a bit tight, or have a slight burr in it. I had a SBC in 69 Vette that had bronze liners installed just a little too tight. Ejected the liners off the exhaust guides on the two rear cylinders as they run a bit warmer because of waterpump placement.
Bottom line is, you probably won't know for sure until the head comes off so you can inspect and measure things.
Todd

[135sohc]

The lifters are OEM chrysler 2.4 w/shim washer but I did take the lifter out and see that it appeared to be fine. Given the I will just say questioanable quality of the machine shop I used in 2011 it would not come as a surprise if they did part or all of the dirty industry methods like Todd described. The car has been running its normal daily routine for the past 3 days now and so far nothing has let loose. Kind of at the cross roads of whether or not I want to continue on w/2.2 'next gen' or get serious and start planning out the 3.5

[Vigo]

3.5 v6? Do tell..

[135sohc]

A 3.5 with the 4 speed automatic in the conventional east-west layout. This is strictly a tinkering idea in my head, I dont even have an engine to begin figuring out how one even mounts in the conventional FWD cars.

[Vigo]

Well, considering it shares a bellhousing with the 3.3/3.8, 2 out of 3 mounts would be stock. I've been sitting on a locked up 3.5 for years and years and years in the thought of getting around to mocking it up.

Also, a 3.3/3.8 SBEC will run a 3.5. The intrepid/LH community has shown this. With a hacked 3.3/3.8 SBEC and some moved/extended wires and 2 out of 3 engine mounts already there, it's a pretty feasible idea in my mind.

[135sohc]

A few warning shots but the ugly duckling has returned with vengeance. Now both came off and the exhaust valve is jammed in the down position... There is a racing type machine shop up the road in Waldorf I'll be calling Tuesday and see what they say about reworking this one or other options.

[cordes]

Sorry to hear it. These days it does seem that when someone posts up about a rocker coming off it's not long before they're taking the head off for work.

[135sohc]

Atleast compared to last time I feel that much more confident in how to do things. My real concern is that the head may be nothing more than scrap metal now though after the seat fell out and jammed everything up. If nothing locally pans out then its just going to be a reworked head from ebay.

[cordes]

Atleast compared to last time I feel that much more confident in how to do things. My real concern is that the head may be nothing more than scrap metal now though after the seat fell out and jammed everything up. If nothing locally pans out then its just going to be a reworked head from ebay.

I believe Pat listed a bunch of 8v heads in his for sale thread very recently. You may want to check it out.

[135sohc]

Dropped everything off at Gunthers this afternoon. I came away from there ~impressed~ the locals are a sorry pathetic joke in comparison.

Complete redo of the head, threaded plugs in the oil gallery ends ect. This time and for any future builds the headbolts are staying on the shelf, its getting reinstalled with studs.

[GLHS60]

Welcome to the dropped seat club!!

Are you repairing the original or starting over??

Thanks
Randy

[135sohc]

I left the original there along with another used one I got a couple years ago. The intention is to reuse the original, its cracked in all the usual spots but so is every other head out there unless NOS and I have one but it would just crack anyways.

[135sohc]

In measuring both the NOS head and a used head from what I am calling a factory assembled engine in the 'machine limit' recessed pad on the front the depth is right around .090 deep. The cylinder head that dropped the seat and is getting redone was the same head that I had redone in 2011 when I redid the whole engine and measuring it I was getting around .078 deep. I mentioned this at the machine shop and Jeff was not uncomfortable with it but just to be aware of it, he certainly was not going to take off any more than absolutely necessary if the head was not flat. When setting up the timing belt in the past after the rebuild I did notice the belt in relation to the timing marks is a bit 'sloppy' because of that lost height. I am going to assume the worst and think another .005-.007 will be removed this time around. How well do the felpro head saver shims work and how do they work ? Copper spray and torque it down with the gasket ?

[cordes]

What have you calculated the increase in CR to be? I'm too lazy to do that at this time. IMO I wouldn't run a shim, but I would degree the cam and use an adjustable cam gear to get the timing where it should be.

[Vigo]

I've been messing with my tbi-piston van a bunch lately and it only seems to pick up knock counts ~2 psi earlier than stock turbo pistons on an otherwise stock setup. That's with a fairly serious compression ratio increase. With stock overboost in place I don't think it would ever even break. I don't think a shaved head is really worth worrying about unless you are trying to make serious power.

[turbovanman²]

The shim works fine, used one in my TIII with lots of boost, held just fine. Copper spray and bolt her down.

[135sohc]

Ok so 1 week in service and all hell broke loose this morning... Engine was bucking and breaking up, cut off twice. Hoping its just the hall effect deciding to be a POS.

[wheming]

I've used a copper shim on my spirit for 20 years. Never blew a headgasket on that car and used to run 25psi all the time racing, and have also on the street. The can be mounted above or below the headgasket, see it both ways. I had mine on the block side.
Or, if you are doing studs, you can just get one of those thicker Cometic gaskets, if it works out to be the correct thickness for the compression you want.

From your other update about the lower compresdion in one cylinder, i wonder if you have cracked one of your rings?

Sent from my SAMSUNG-SM-G870A using Tapatalk

[135sohc]

Not to count anything out yet but I am thinking #4 does have a broken top ring, its been suspect for awhile now and with the higher compression on 1-3 now its just that much more sensitive to the difference in cylinder pressures. They were expensive but those ARP studs are awesome.

[minigts]

What's happening with this? I missed the thread originally, but now curious as to what the issue is? Good luck with it though!

[135sohc]

The current issue ~I think~ is the now higher compression on 1-2-3 from the head getting resurfaced and the lower compression on 4 because of a suspected broken ring is causing an in-balance and the engine cannot compensate when placed under certain conditions like stop and go driving and extended idle time.

[cordes]

The current issue ~I think~ is the now higher compression on 1-2-3 from the head getting resurfaced and the lower compression on 4 because of a suspected broken ring is causing an in-balance and the engine cannot compensate when placed under certain conditions like stop and go driving and extended idle time.

At 313,00, are you thinking of a rebuild?

[135sohc]

It was already redone at 260. Then this little hiccup occurred and its just dragged out... Got a ball hone and a leakdown tester. Along with two sets of moly rings and 2 sets of rod bearings. Worst case I'll re-do all 4 pistons if the leakdown is bad, otherwise just #4 and keep on racking the miles up.