Weber selection and initial jet tuning

[blodi]

Ok, got my valve spring removal tool yesterday finally.  So I removed the retainer/spring from the valve in question (#4 intake). 

IMG_4715 by blodi, on Flickr

There was a washer under the spring and one under the valve seal as well....normal? 

IMG_4716 by blodi, on Flickr

Washers and new valve seal installed....

IMG_4717 by blodi, on Flickr

New Schneider valve spring and retainer on left....old on right...

IMG_4718 by blodi, on Flickr

.170 lash pads installed in each...

IMG_4719 by blodi, on Flickr

Installed......

IMG_4721 by blodi, on Flickr

Rocker arm back in place and lash adjusted....

IMG_4723 by blodi, on Flickr

 You can see that the lash pad certainly fits much further down into the Schneider retainer than the old one. 

I started the car for about 30 seconds and then my 1 year old woke up and I had to  call it a night.  Didn't hear any tapping though....but hopefully tonight I'll have a chance to start it up and let it warm up and see what is what. 

If all is well...I'll have to maybe spend my day off on Monday replacing all the rest of the springs retainers. 

Oh, also...I was able to spin the valve around freely and didn't feel any binding. It had just a tiny amount of play in the valve guide...not sure what is "normal" there but it didn't feel excessive. 

 

[siteunseen]

Yes those steel washers are original.  They're for the inner and outer springs to sit on.  I call them spring seats.  My thinking is to keep the steel springs from tearing into the aluminium head?

That old one was so low I think the rocker arm was hitting the sides of the retainer, not just the tip of the rocker into the lash pad.  The different heights are amazing looking at the photos.  I don't understand how they can be that much different and still have a good wipe pattern? 

EDIT: I've done it before so I tell you and maybe you won't. 

Put those steel washers down first.  The valve seals won't fit over them.

Edited March 29, 2018 by siteunseen

[blodi]

Yes, I did reinstall the washers before putting in the new seal. 

My understanding is that ultimately the wipe pattern is setup by the lash pad as it still sits directly on top of the valve itself since it's flat on the bottom. So the retainers shouldn't have any impact on that geometry.  

The picture of the pads sitting in the retainers before installation isn't really representative of how they sit once installed on the valve. 

 

[blodi]

Ok, well.....got home from work and fired it up again. Sure enough the tapping came back after about a minute of running. Then after another minute or so and a few quick revs the tapping got really bad...so I shut it off. 

Pulled the valve cover and saw that now hte #4 valve was not up to it's full up position even though the lobe was not pushing down on it     Got my bore scope out and looked in the spark plug hole and could see a fresh mark on the piston from the intake valve. 

Then went though the intake and can see that the valve seat came completely loose.  Fack. 

So....that's my Thursday night.  Going to think about how to proceed.  Might wait and have my friend who is wrapping up an engine rebuild on my NSX have at it once he is done with that car  in a couple weeks.  He'll be able to comb over everything much better than I could and he's basically an NASA engineer when it comes to assembling and inspecting engines.  Not the outcome I was hoping for but it is what it is.  Not sure why the seat came loose in the first place, but it all makes a lot of sense now. 

 

[Captain Obvious]

Well that sucks. So far, you've had a lash pad fly out... twice. And a valve seat come completely out of another location, right?

That head is clearly questionable and I wouldn't do anything else without it until it's been seriously evaluated.

[siteunseen]

Hard to believe that a valve will go through a valve seat and let it fall down on the piston's top.  Sounds like that could have gone bad really fast if it weren't for your cautious ears and sleeping 1 year old.   I think that's one of the top 5 crazy things I've heard on here, so far. 

Was the old brass/bronze seats?  I had to change mine after Phillip pointed out how bad they were beaten down on an E31 I have.  They were exhaust only, the intakes had been replaced with steel to match the bigger intake valves he had put in.

[blodi]

4 hours ago, siteunseen said:

Hard to believe that a valve will go through a valve seat and let it fall down on the piston's top.  Sounds like that could have gone bad really fast if it weren't for your cautious ears and sleeping 1 year old.   I think that's one of the top 5 crazy things I've heard on here, so far. 

Was the old brass/bronze seats?  I had to change mine after Phillip pointed out how bad they were beaten down on an E31 I have.  They were exhaust only, the intakes had been replaced with steel to match the bigger intake valves he had put in.

The seat looks to have come loose and wedged itself between the valve and head. It didn’t drop to the piston but rather held the valve down enough to tap the piston. 

4 hours ago, Captain Obvious said:

Well that sucks. So far, you've had a lash pad fly out... twice. And a valve seat come completely out of another location, right?

That head is clearly questionable and I wouldn't do anything else without it until it's been seriously evaluated.

This has all been on the same #4 intake valve. So I think the seat had been coming loose and causing the valve to close slowly and this getting the tapping and eventual loss of the lash pad each time. This time since the lash pad wouldn’t come out being lower into the retainer...the seat came completely out. 

[gundee]

On 3/2/2018 at 11:34 AM, Lumens said:

blodi if this motor was a spare race engine as stated, do you mean spare never run or used but pulled as a back up engine.

This motor may have been run very hard previously. If so I might think about pulling head to have it checked out.

I know thats a lot of work but as long as it still Winter time.....

On March 2nd I mentioned maybe pulling the head. I would say this is a must now.

I think this head has some machine work issues. Nothing more can be done up top. IMO.

[blodi]

9 hours ago, Lumens said:

On March 2nd I mentioned maybe pulling the head. I would say this is a must now.

I think this head has some machine work issues. Nothing more can be done up top. IMO.

Agreed. I am going to start pulling the carbs/intake/header on Monday since I have the day off. I ordered a timing chain wedge yesterday. 

When the head is off I’ll let my friend/mechinc have at it  

I think at minimum a new valve seat will need to be installed and the valve replaced.  I’ll have him inspect all of the valves and seats though. 

[siteunseen]

I'm almost positive my machinist used seats from a Dodge hemi engine for the exhaust valves on my Z.  He had a bunch of those on hand.  Just an FYI...

[Mike W]

A very similar thing happened to me about a year ago. All of a sudden the car had no power and did not sound right.  Traced it down to the #4 cylinder and was hoping for something electrical, but no cigar.  Ended up pulling the head only to find the seat on the #4 intake had come loose and was not allowing the valve to fully close.  Brought it to my machinist and we ended up replacing all of the seats, many of which were the original brass ones installed at the factory.  His theory is that with the ethanol based fuel and the higher burn temps, the brass seats were not designed for this and as a result they loosen over time and eventually fail.  There was another one that he found that was about to do the same thing.  Replaced them all with steel and so far no problem.

[blodi]

Mike, sounds exactly like what happened here.  I have to believe my seats have all been upgraded since every other part of this engine has been upgraded. It was hard to tell on my grainy bore scope.