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T4 engine - all of a sudden, 1/4" play between rocker and valve?
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MikeyM73
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PostPosted: Thu Feb 20, 2020 2:10 pm    Post subject: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

1.7L all stock (as far as I know), solid lifter cam. So it sounds like something pretty major happened but I'm not sure what. Have never experienced this with solid lifters. Prior to the following, it was running fine. After sitting for 4 days, I went to start up the bus and immediately noticed a loud tapping and what sounded like it running on 3 cylinders. After checking the ignition and all was fine, I pulled the valve covers and found that #3 cylinder had literally about 1/4" play between the valve stem and rocker arm. or the push rod to the lifter, however you look at it. I could rock the rocker arm back and fourth about 1/4" and the PR stayed with the rocker as I did (although it would easily separate if I pushed it off with a screwdriver) . So I pulled the rocker arm assy and the adjusters are evenly worn and were tight, the PR was straight with both ends looking normal, and both valve springs were the same height. I shined a light down the PR tube and saw what looked to be the center of the lifter and didn't see any pieces of metal in the PR tube.. I ran a magnate down the tube and got nothing. So that tells me that the lifter or something further down needs serious help. Do the solid lifters have multiple pieces to them? Could a lifter break internally causing it to essentially collapse? The only thing I can think of is that, if so, one lifter bit the dust or my cam broke or some other really bad thing. The only other thing I can fathom is that these are hydraulic lifters and one collapsed although I don't think that is the case. Looks like it's time for me to start pulling the engine. Thoughts?

Thanks,
Mikey
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.
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Clatter
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PostPosted: Thu Feb 20, 2020 2:32 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

Pull the lifter.

Let's have a look at it.

You can also shine a light in there and look at the cam lobe.


Luckily it's a type 4.. Wink
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Wildthings
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PostPosted: Thu Feb 20, 2020 2:33 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

I would certainly pull the questionable lifter and examine it. Very easy to do on a Type 4 engine, you are almost there already.
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PostPosted: Thu Feb 20, 2020 2:33 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

Also pull one of the others next to it..

Pushrod tubes come out easily.
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MikeyM73
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PostPosted: Thu Feb 20, 2020 2:50 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

Thanks guys, will do. I've had the PR tubes out before to change PR tube seals so I'll do that soon and report back.

Question, is it possible for a "solid" lifter to break internally? If so, I've never seen it before.

Thx.
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.
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PostPosted: Thu Feb 20, 2020 3:06 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

They are 2 piece, the PR section is pressed into the hollow main body, and there is a chamber above it, possible that section broke allowing the added clearance, I cut 1 in half, don't remember but a 1/4 sounds about right
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Wildthings
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PostPosted: Thu Feb 20, 2020 3:26 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

MikeyM73 wrote:
Thanks guys, will do. I've had the PR tubes out before to change PR tube seals so I'll do that soon and report back.

Question, is it possible for a "solid" lifter to break internally? If so, I've never seen it before.

Thx.


Never seen one break internally, but I had a Toyota one crack a big chunk off of the face end one time.
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raygreenwood
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PostPosted: Thu Feb 20, 2020 3:29 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

Its also possible that you somehow got a bent valve stem or the bottom of a guide broke off and is still around the stem and causing issues. Its also possible a sear is loose...cocked in its bore and is holding the valve ipen

Pop the valve cover off....turn the engine through all four cycles.

The question is.....is that rocker arm rising up HIGHER than the others.....or is the valve tip NOT rising up as high as the others. Ray
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PostPosted: Thu Feb 20, 2020 4:10 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

Thanks guys. Upon further inspection (rocker shaft assy removed), it looks like the lifter is probably fine. I noticed that the inside valve (closest to the middle) looks like it's not closing or coming back to rest as the other valve is. It is not the same height as the one on the outside. With the rocker shaft assy removed, the outside valve's spring retainer is above the valve cover mating surface while the inside one is clearly below - like the valve is open. I think Ray may have pegged it. Bent valve, dropped seat, or something similar holding the valve open. Ray what is this "sear" that could be loose holding the valve open? For what it's worth, I pulled a plug but can't see in there too well.

Thanks,
Mikey
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.
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MikeyM73
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PostPosted: Thu Feb 20, 2020 4:37 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

Well.. due to my old(er) age, I forgot that I had a secret weapon.. through the miracle of modern technology, I managed to get my mini-flexible camera down the plug hole and guess what I saw... WEAK!

Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


The pics aren't great but the real-life view is better. If I were a betting man, I'd say that thar be a dropped valve seat. I'm not aware of anything else that lives inside a combustion chamber / cylinder that would look like this. What's odd is that it was running perfectly and the CHTs were low when I shut it off a few days ago. Who knows. This engine was LOOONG overdue to be pulled and loved on.

So.. I have this fully intact FI 2L in my parts bus. Thinking of just pulling it, swapping over my ignition, intake, and exhaust just as-is and running it. Then taking the 1.7 and turning it into a new 2L or slightly stroked. Not sure yet. Anyway, there ya have it.

Mikey
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.
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PostPosted: Thu Feb 20, 2020 5:00 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

Sorry......typo on phone......."sear" was supposed to be "SEAT" Laughing

Ray
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MikeyM73
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PostPosted: Thu Feb 20, 2020 5:03 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

Yup. Ray, you win the 64 bucks.
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.
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PostPosted: Thu Feb 20, 2020 5:14 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

MikeyM73 wrote:


So.. I have this fully intact FI 2L in my parts bus. Thinking of just pulling it, swapping over my ignition, intake, and exhaust just as-is and running it. Then taking the 1.7 and turning it into a new 2L or slightly stroked. Not sure yet. Anyway, there ya have it.

Mikey


That sounds like the best plan to keep you on the road...kinda like the 2.0 I bought to replace the original with no oil pressure. I ran that $400 replacement for a few years and then it had no oil pressure the rebuilt original went back in. The replacement is still awaiting teardown for maybe rebuild. Seeing as how it had GEX heads on it I don't have a lot of hope.
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PostPosted: Thu Feb 20, 2020 6:17 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

Well, for what it's worth, a phone call to Brothers Machine yielded a brand new set of AMC heads with 42/36 valves and good parts for under 1400 bucks so maybe that could be an option.

For me, at this time, it's between Len Hoffman, Brothers, and Headflow Masters. Kinda leaning toward Len because he's been doing this a long time, I've actually spoken with him, and he gives options from mild to wild. Plus his prices are fair for a damn good product.

Anyway, just thoughts from the peanut gallery.
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.
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PostPosted: Thu Feb 20, 2020 7:29 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

It is actually pretty normal for an intake valve seat to fall out of a cold head.
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PostPosted: Thu Feb 20, 2020 8:26 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

It’s also somewhat common for a loose seat to follow the valve.

Seat will stick to the valve and follow it,
Seating area becomes where the seat would normally rest in the head.

Until the seat cocks sideways and doesn’t come home,
Nobody would know it’s happening.

Pulled more than one apart where the seat was following the valve..

Lucky you it decided to go sideways while it was shut off.
A windowed case can be your prize otherwise.. Wink

I’d be running a leakdown on any core motor before deciding to commit the time of stuffing it.


It’s OK,
April 11 is still a few weeks away.. Wink
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PostPosted: Fri Feb 21, 2020 2:16 am    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

I think usually the seat doesn't quite have time to drop right out while the engine is running so it gradually wallows out the head until it either drops out if the engine happens to stop with that valve open or drops out just as you change gear and the revs drop when the engines at running temp.

The second one happened to me, 1700 in a bus. I had really abused that engine though in terms of not servicing and driving it hard. It kind of didn't matter 25 years ago when a whole turnkey previously loved engine was half the price of a head. I tried to sell a perfectly good 1700 long block here for £50 about 10 years ago and there were no takers. It's only problem was that I'd tipped a box of washers down the breather. Very Happy Lucky really because the heads are now on my 2.4.
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PostPosted: Fri Feb 21, 2020 7:44 am    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

MikeyM73 wrote:
Yup. Ray, you win the 64 bucks.


If you pry on of rays dots......off the screen you will find it is fact a microdot containing the sum of all known knowledge on VWs. he has compiled it from people who are really technical, here, and elsewhere.
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PostPosted: Fri Feb 21, 2020 8:58 am    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

Well how bout that. Didn't know those facts WT and Steve. I will absolutely do those tests before I go through all the labor to R&R the engine/trans combo. Now it's a matter of figuring out who's head to go with. Brothers' says AA just started making new casting in addition to AMC - the person I spoke with said he feels the quailty is the same for about 100 bucks less per head. Plus they still R&R them with larger SS valves and all the rest of the good parts, etc., which seems like a pretty good deal. Not sure if it's too good to be true - just under 1100 bucks for new heads. And a light port is another 300. I've heard good things about Brothers - anyone else?

So with new head castings, new, modern-day seats, etc., I would imagine valve seat issues would be a thing of the past as long as the temps stay in check, correct?

Let the fun begin.



[/quote]
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.
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PostPosted: Fri Feb 21, 2020 12:20 pm    Post subject: Re: T4 engine - all of a sudden, 1/4" play between rocker and valve? Reply with quote

If you can swing a set of Len heads, do it IMHO.

I have been severely abusing a set for over ten years now.. 15? Shocked

42x36..

I'd wait until the jury was out before trying anything new.
Sometimes new things don't play out as expected.
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