Exhaust valves

Mrgabesir · **Joined:** Mon Feb 25, 2013 5:21 am **Posts:** 67

How critical is it to replace the exhaust valves and seals when pulling the head? I am replacing the head gasket, was recommended to replace the ex valves at the same time? Whats the best source? ID seems to sell them individually, don't know if someone has sets for cheaper?

WWDiesel · **Posted:** Fri May 24, 2019 4:33 pm

Mrgabesir wrote:

How critical is it to replace the exhaust valves and seals when pulling the head? I am replacing the head gasket, was recommended to replace the ex valves at the same time? Whats the best source? ID seems to sell them individually, don't know if someone has sets for cheaper?

Unfortunately not a lot of choices out there for suppliers for replacement valves.

If you have the head off for any reason, it is well worth the money and piece of mind insurance to replace all the exhaust valves and this is why:

There have been some Jeep CRD owners on this forum who have reported a dropped valve on their engines most especially after they meet or exceed the 150k mile mark.
When this happens it tends to be catastrophic damage that incurs usually taking out the cylinder head, a piston, and cracking the piston liner.
In a few rare instances, it has broke the connecting rod along with the other items and the broken connecting rod punches a hole out the side of the block which totally destroys it.
So you can understand the thought process and rationale for replacing all the exhaust valves whenever possible.

It can be a big and possibly very expensive gamble.
Some owners have reported going over 300k without a failure on original valves while others have reported a failure at much less than the 150k mark.
At this point we do not know for sure what the exact root causes of the failures are. Suspects that have been discussed are overheating (extreme EGT's), valve metal embrittlement, and a few other theories. Nothing proven so far on cause.
There have been metallurgy tests performed on some of the failed valves verses a good valve, but unfortunately nothing definitive as to the cause came out of the test results.
Another theory is maybe a "bad" batch of valves was produced by a vendor supplier to VM Motori so only those valves are prone to separation. But no way to prove or disprove this either.

Bottom line, If I pull my head or even go into the engine for it's second timing belt, I will replace all the exhaust valves and rockers.
I certainly will sleep better at night knowing I have done all that I can to prolong the life of this very unique little diesel vehicle which I love..... :rockon:

geordi · **Posted:** Fri May 24, 2019 4:47 pm

WWDiesel wrote:

Bottom line, If I pull my head or even go into the engine for it's second timing belt, I will replace all the exhaust valves and rockers.
I certainly will sleep better at night knowing I have done all that I can to prolong the life of this very unique little diesel vehicle which I love..... :rockon:

This is important enough to bear repeating. If there is ANY reason to remove the head, just replace the valves. The cost is either $150 for only exhaust or just under $300 for all of them. This is a no-brainer decision when the result of guessing wrong can be $3000 or more if the block is damaged.

vwroad87 · **Posted:** Fri May 24, 2019 7:41 pm

Speaking of heads, when I changed my head with a brand new one at 96K (so glad I did now) I still have the other perfectly good head (no damage from a broken TB) where can I get it rebuilt I would like all the valves replace and the burled up aluminum that happens from the factory torque to yield bolts sans washers creating milled flat. I'm in the Western Washington State area.

thanks

TKB4 · **Posted:** Sat May 25, 2019 9:34 pm

I don't have an answer but just some observations. I have personally been told that the heads are "non serviceable" when i asked the machine shop said they were not meant to be machined flat if warped etc. I believe that is the position of chrysler also but many here have had heads machined prior to head gasket replacement. It is my understanding that they can be machined up to about 3 thousandths without harm. Each set of intake and exhaust valves from VM diesel specialists a year ago cost 64 british sterling plus shipping and duty and takes 2-3 weeks for delivery. Right now with exchange 64 british sterling is about $82 plus shipping and a small duty and you may have to pay by bank wire transfer. I would think overall about $120 or less for one set and about $205 or so for intakes and exhausts or 2 sets of exhausts since wire and shipping essentially the same.

I echo the strongest recommendation to replace the exhaust valves!!!

WWDiesel · **Posted:** Sat May 25, 2019 10:01 pm

The reason they recommend not to have this head machined is due to the fact that from the factory they have applied a very thin coating of nickel to the aluminum mating head surface and if you machine the head you will remove this coating. We feel it is for better heat transfer purposes.

Some have had their heads machined successfully with no consequences, but there is not a lot metal on the mating surface of the head that will allow this.
These engines have some very close tolerances between the valves and the pistons so machining the head further narrows these clearances.
If you choose to have your head machined, you should go to a thicker head gasket to compensate for the material loss...

geordi · **Posted:** Sat May 25, 2019 10:53 pm

Some things to consider:

I just had the opportunity to work on a head that arrived fresh from the VM Specialist. For anyone unfamiliar, they are a "breaker" in Europe. Commonly known in the USA as a wrecking yard. The valves in this head were FULL of pitting and longitudinal cracks between the "coin" of the valve and the stems. Would I use these valves? NOT A CHANCE.

The head itself had been cleaned (for the most part) but there were still some gummy intake runners that cleaned up with brake cleaner and some brush wiping. With a fresh (NEW) set of valves, this Jeep is now running VERY well.

VM Specialists are a good source for heads, but there is very little that I have seen that encourages me to think that the valves they sell for $120/$205 are anything other than USED. The problems we are having with the valves are serious enough that using USED valves is just such a terrible idea.

layback40 · **Posted:** Sun May 26, 2019 12:26 am

geordi wrote:

Some things to consider:

I just had the opportunity to work on a head that arrived fresh from the VM Specialist. For anyone unfamiliar, they are a "breaker" in Europe. Commonly known in the USA as a wrecking yard. The valves in this head were FULL of pitting and longitudinal cracks between the "coin" of the valve and the stems. Would I use these valves? NOT A CHANCE.

The head itself had been cleaned (for the most part) but there were still some gummy intake runners that cleaned up with brake cleaner and some brush wiping. With a fresh (NEW) set of valves, this Jeep is now running VERY well.

VM Specialists are a good source for heads, but there is very little that I have seen that encourages me to think that the valves they sell for $120/$205 are anything other than USED. The problems we are having with the valves are serious enough that using USED valves is just such a terrible idea.

Would be great to have pics of some of these valves on the failure research thread. IIRC the engine is used in London taxis & the valves have probably had a long but easy life. The guys that did the testing onthe exhaust valves in the report may be interested in having a look at the cracked valves.

TKB4 · **Posted:** Sun May 26, 2019 2:06 am

The two used heads I bought from VM Diesel Specialist were in excellent condition. They ordered the brand new valves directly from vm matori (at least thats what I was told and they looked new) and installed them in the used heads free. So for about $336 ( 4 sets of valves 2 exhaust and 2 intake sets) extra cost I got essentially two brand new heads . It did however cause about a ten day longer delay.

Mrgabesir · **Joined:** Mon Feb 25, 2013 5:21 am **Posts:** 67

Thanks All, will I need to replace all the seats and seals? darn, this is getting expensive.

flash7210 · **Posted:** Mon May 27, 2019 5:53 pm

You should always use new seals with new valves.
New valves should be lapped into the old seats.
Search YouTube for “lapping valves”

geordi · **Posted:** Mon May 27, 2019 8:11 pm

The valve guides are pressed into the head, and have a spring seal on the top. To date I have not replaced any of them, and the valves coming out do not show any signs of wear that would suggest that the seals or guides need replacement.

The seats are also pressed into the head, and both they and the guides would need a machine shop assistance to replace them. When I replace the valves in the field they are all lapped in to the seats, and the result is liquid tight even when sitting overnight. This is more than sufficient, and the only failure point I have been aware of has been the alloy valve stems themselves - which is why the valves need to be replaced before they have roughly 200k miles on them.

Mrgabesir · **Joined:** Mon Feb 25, 2013 5:21 am **Posts:** 67

Any alternatives to the VM valve seals that might be more readily available?

geordi · **Posted:** Fri May 31, 2019 4:58 pm

IDparts has the VM valve seals, but you will need professional assistance to replace them b/c of how they are installed. To date out of the 40 or so heads I have worked on and over a hundred more that others have done, I have not heard of a single case of any issue with the seats or seals. Only the valves themselves have been an issue.

krb · **Posted:** Wed Jun 05, 2019 5:07 am

IDParts has the valves but I don't see the seals listed (seems odd). Where do youall get the seals?

WWDiesel · **Posted:** Wed Jun 05, 2019 3:20 pm

krb wrote:

IDParts has the valves but I don't see the seals listed (seems odd). Where do youall get the seals?

https://www.idparts.com/valve-stem-seal ... -3857.html

krb · **Posted:** Thu Jun 06, 2019 5:37 am

Ah, thanks, page 2...

Rabbit566 · **Joined:** Wed Mar 21, 2018 9:45 am **Posts:** 5

Has any one found a different exhaust valve manufacture? I had a water pump failure and I'm trying to decide on what valves to purchase. I found a set on Ebay that state they are better than OE but nervous about that...and IDparts has the OE.

I want to think the folks on here for sharing all the great information. I know it takes extra time and effort to take pictures and write up "how to's" and the while cursing for needing to replace parts anyway.

I'll probably just go with OE unless it's as easy as sending a valve to "X" shop and they make a copy.

-Rabbit

2005 Liberty CRD
1997 Grand Cherokee Limited

WWDiesel · **Posted:** Fri Jun 14, 2019 3:40 pm

Rabbit566 wrote:

Has any one found a different exhaust valve manufacture? I had a water pump failure and I'm trying to decide on what valves to purchase. I found a set on Ebay that state they are better than OE but nervous about that...and IDparts has the OE.
I want to think the folks on here for sharing all the great information. I know it takes extra time and effort to take pictures and write up "how to's" and the while cursing for needing to replace parts anyway.
I'll probably just go with OE unless it's as easy as sending a valve to "X" shop and they make a copy.
-Rabbit
2005 Liberty CRD
1997 Grand Cherokee Limited

If anyone has located a better set of valves than the OEM ones it would be great news for many on this forum since there have been some concerns raised as to the quality of the OEM ones. :juggle:

Best I know the OEM VMI valves are the only ones available at this time.

If you find some some better ones, please share...

layback40 · **Posted:** Fri Jun 14, 2019 7:30 pm

Rabbit566 wrote:

Has any one found a different exhaust valve manufacture? I had a water pump failure and I'm trying to decide on what valves to purchase. I found a set on Ebay that state they are better than OE but nervous about that...and IDparts has the OE.

I want to think the folks on here for sharing all the great information. I know it takes extra time and effort to take pictures and write up "how to's" and the while cursing for needing to replace parts anyway.

I'll probably just go with OE unless it's as easy as sending a valve to "X" shop and they make a copy.

-Rabbit

2005 Liberty CRD
1997 Grand Cherokee Limited

Can you please provide a link to these non OE valve on ebay.

Exhaust valves

Who is online