Random Misfire while cruising

[AK260]

Here’s a great write from my buddy in the UK who recently did this job - it would be very beneficial for you to read it ....

https://zclub.net/community/index.php?threads/valve-stem-oil-seal-replacement-without-the-faf.28265/

[jalexquijano]

On 5/12/2021 at 4:33 PM, AK260 said:

 

You will not mess it up. In fact your risk of having issues will be much higher with the head removed.

I totally get the logic but for now, if I was in your shoes and knowing that only cyl 4 is fouling, I would just focus on that one. You know the others are good as there is no fouling on the other plugs.

Follow the procedure given further up in the thread on doing it with the head on.
 

 

What are the risks of going the easy way and remove the complete head cylinder instead?

[AK260]

The easy way saves you a lot of time and money.

The hard / head off way introduces lots of time consuming work and risks!!

Hard way:

You need to remove the intake and exhaust manifolds - possibly likely to introduce air leaks when you put them back.


You’ll need a new head gasket and a new intake / exhaust gasket.

I would say you need new head bolts as they stretch and I wouldn’t like to reuse them.

There is a potential for threading head or other bolts when you put them back. What if a head bolt snaps on the way out? You then have to take the rest of the engine out to deal with it.

It’s easy to mess up your cam timing and potentially have valves kissing a piston and bending / killing your engine.

Many other risks I can list but I won’t.

The easy way:

is simply a case of stuffing some rope into the spark plug hole, turning the engine to TDC on that piston and dealing with valve springs / seals on that one cylinder.

You only then have to worry about getting the seal / springs back on properly and make sure you have correct valve clearances.

[siteunseen]

9 hours ago, AK260 said:

The easy way saves you a lot of time and money.

The head off way introduces lots of time consuming work and risks!!

Hard way:

You need to remove the intake and exhaust manifold - possibly likely to introduce air leaks when you put them back.


You’ll need new head gasket and intake / exhaust gasket.

I would say you need new head bolts as they stretch and I wouldn’t like reusing them.

There is a potential for threading head or other bolts when you put them back. What if a head bolt snaps on the way out? You then have to take the rest of the engine out to deal with it.

It’s easy to mess up your cam timing and potentially have valves kissing a piston and bending / killing your engine.

Many other risks I can list but I won’t.

The easy way:

is simply a case of stuffing some rope into the spark plug hole, turning the engine to TDC on that piston and dealing with valve springs / seals on that one cylinder.

You only then have to worry about getting the seal / springs back on properly and make sure you have correct valve clearances.
 

I think he has the easy way confused with the hard way.

Hard way=remove head

Easy way= leave head on

[AK260]

I thought I was clear but clearly not ;)

[siteunseen]

6 hours ago, AK260 said:

I thought I was clear but clearly not 😉

Maybe not. and could be or? 

What are the risks of going the easy way and remove the complete head cylinder instead?

[Mark Maras]

@jalexquijano Everyone agrees there's no need to remove the head to change a valve seal and if you do you may be opening a Pandora's Box of trouble and expense. The compression is good on all cylinders so we know the rings and valves are sealing. The only problem is a fouled #4 plug which, by process of elimination, we've come to believe is a leaking valve seal. Installing one valve seal is a piece of cake compared to pulling and reinstalling the head. 

[jalexquijano]

20 minutes ago, Mark Maras said:

@jalexquijano Everyone agrees there's no need to remove the head to change a valve seal and if you do you may be opening a Pandora's Box of trouble and expense. The compression is good on all cylinders so we know the rings and valves are sealing. The only problem is a fouled #4 plug which, by process of elimination, we've come to believe is a leaking valve seal. Installing one valve seal is a piece of cake compared to pulling and reinstalling the head. 

Im trying to get the spring retainer locally and an air compressor to keep the valve from falling. 

[AK260]

18 minutes ago, jalexquijano said:

Im trying to get the spring retainer locally and an air compressor to keep the valve from falling. 

Good man! You're doing the right thing! 👍

 

Looking forward to hearing about your successes. 

[jalexquijano]

7 hours ago, AK260 said:

Good man! You're doing the right thing! 👍

 

Looking forward to hearing about your successes. 

I need to buy this spring retainer prior to anything. Which brand would you recommend or will this one suffice? What happens if the valve falls and i need to take the cylinder head out? Should i also order some bolts and extra gaskets to complete this job successfully?

[AK260]

 

You know, I relate to what you are saying! Many of us tend to over analyse / over think these things. They seem scary at first until you actually do the job and find it was a lot of fuss over nothing! 😉

 

Don't know the brand, but given that you are only doing 1 job with that tool and you're not a professional mechanic doing many of these every day, I think it will be just fine for your purposes. 

 

Don't go buying bolts etc. If you bring cyl 4 to compression TDC (both ex and intake cam lobes pointing up) and use the rope or compressor method, you won't be losing your valves. If I recall correctly, you literally have mere millimetres of valve to piston clearance, so it's very very unlikely that you will be loosing the entire stem down the valve guide without being able to recover it. I await someone to correct me. The compressor (or rope) just helps keep the valve at the top (shut) so that you can easily put the springs / caps etc back on.

 

If you want to buy any additional items, get a new cam cover gasket - a decent one that doesn't fall apart, so that you can reuse it when you next take the cam cover off. Don't forget to scrape off / clean up the residue from the old gasket first as some of them leave pieces of themselves behind. Also make sure any residue doesn't end up in your oil. 

https://www.thezstore.com/page/TZS/PROD/classic12a13/10-2491C

 

This is not a Z car, but a very good video - I like the Vaseline idea!

 

 

Edited May 19, 2021 by AK260

[jalexquijano]

On 5/19/2021 at 5:53 AM, AK260 said:

 

You know, I relate to what you are saying! Many of us tend to over analyse / over think these things. They seem scary at first until you actually do the job and find it was a lot of fuss over nothing! 😉

 

Don't know the brand, but given that you are only doing 1 job with that tool and you're not a professional mechanic doing many of these every day, I think it will be just fine for your purposes. 

 

Don't go buying bolts etc. If you bring cyl 4 to compression TDC (both ex and intake cam lobes pointing up) and use the rope or compressor method, you won't be losing your valves. If I recall correctly, you literally have mere millimetres of valve to piston clearance, so it's very very unlikely that you will be loosing the entire stem down the valve guide without being able to recover it. I await someone to correct me. The compressor (or rope) just helps keep the valve at the top (shut) so that you can easily put the springs / caps etc back on.

 

If you want to buy any additional items, get a new cam cover gasket - a decent one that doesn't fall apart, so that you can reuse it when you next take the cam cover off. Don't forget to scrape off / clean up the residue from the old gasket first as some of them leave pieces of themselves behind. Also make sure any residue doesn't end up in your oil. 

https://www.thezstore.com/page/TZS/PROD/classic12a13/10-2491C

 

This is not a Z car, but a very good video - I like the Vaseline idea!

 

 

Unfortunately i havent been able to change the valve seals. I did took the car for a spin on sunday under very light traffic and when removing spark plugs 4 and 6 did noticed any oil on them. Maybe i should leave the car idling for 10 or stop and go traffic so the oil is indeed present. Any thoughts? First 3 pics is sp 4 and last one is 6.