Cracked heads

[ttpost]

still working on truck # 1 tdc learn problems, in the mean time truck #2 also 6.5 94 diesel blew a headgasket. while i had it apart i decided to do a valve job, so i hot tanked the heads and upon clean up i noticed i have cracks between the intake and exhaust valves on all cylinders, the truck ran well until the head gasket blew, due to finances right now i cant afford new heads. i have no choice to run what i have for now, i assume these were cracked for along time before the head gasket blew, i never have over heated it and i have owned for most of its life. does anyone have any suggestions, or ideas on what kind of problems i will be dealing with running the heads as is for now. has anyone else done this and if so what kind of results did you have. thanks rob

[More Power]

We have a tech page in the subscriber section that details how to economically repair these sort of cylinder head cracks (http://www.thedieselpage.com/members/head.htm). ;)

Jim

[ttpost]

Jim, thanks so much. I was able to locate the bushings and i had the reamer, so i have made the repairs and it only cost me 22$, i cant thank you enough. I had thought about something similiar, but i wasnt sure of the dimensions or even if it would work. Once again jim thanks alot rob

[Flatlander6.2]

Jim,
Would the repair that is shown in the members section be suitable if there are cracks that extend into the valve seat?

[ttpost]

flat lander , i assume you found cracks? several of my seats were cracked, i have no choice but to run it as is right now, i did do a valve job since i have all of the equipment. i will be putting the motor in tomorrow, i will let you know how it does. i do have good compression on all of my cylinders so far. i will post updates. i do plan on replacing my heads at a later date. rob

[Flatlander6.2]

I do have cracks, have lapped the valves and will be puting heads on hopefully today. I did compression about 6 weeks ago and was 420 to 435. I too have no choice at the moment than to run as is, but plan on a proper fix at a later date.

[ttpost]

the repair jim recommended is a very easy repair to do i would really recommend it good luck flatlander and i will keep in touch rob

[More Power]

Jim,
Would the repair that is shown in the members section be suitable if there are cracks that extend into the valve seat?

Many of these hairline cracks between the valves do extend into the valve seat area. The repair procedure works for them too. The hairline cracks fill with carbon and don't appear to leak or be a problem over the long haul.

However, if the crack is wider than a hairline, I'd probably look for a new head. If replacing a head, be sure to replace it with one having the same seven-digit casting number (ensures the same valve diameters) and pre-cup design.

As a side note, most of these hairline cracks don't extend far enough into the head to reach the machined cooling passage. That's why most people only notice them when taking the engine apart for some other reason.

I don't hear of it so often now, but there was a time when different shops around the country would attempt to weld the cracks. I don't have any long-term information regarding how effective that sort of repair is. I do know that welding cast-iron engine components can be tricky. The valve guide liner type repair is, in my opinion, more effective long-term.

If any cracks radiate out in some other area of the valve seat, I'd probably replace the head. Some have tried valve seat inserts, and that might be a good solution, but I don't know enough about it.

Jim

[ttpost]

flatlander hows your project coming along, i am up and running. my truck is running alot better than it was and getting better fuel mileage. no overheating problems the trick from jim has been a great help, and the valve job was just the ticket. i bet i gained 40 or 50 hp. i am really pleased thanks again jim. rob

[More Power]

Your're welcome Rob....

Incidentally, I put about 40,000 miles on a turbocharged 6.2L diesel that had about half of the cooling passages in question repaired using that procedure - due to hairline cracks between the valves. No problem during that time. :)

Jim

[ttpost]

JIM, once again i cant thank you enough i have put about 1500 miles on the truck since the repair and it i feel it is running better than it did 130k ago when i bought it. i have always love my truck and now even more. my only regret is that i just put a crank in the 6.5 i bought for my wife and i didnt open up the top end. although it is running good other than my timing problem i think a top end refresh would have been a good idea. i cant thank you enough jim. flatlander hows your truck doing. rob

[Flatlander6.2]

I'm up and running. Could not find a valve guide reamer locally and could not wait (wife out of town with car and no other wheels) so cleaned everything up and put it back together, and it runs even better than before. I am currently looking for a truck to put my 6.2 in. Once that is done I will likely pull the heads again on the 6.5 and fix them with Jim's fix. I really want to try it. On an unrelated note, I am quite happy with the mileage I am getting out of this naturally aspirated 6.5, as high as 25mpg highway and averaging 20 to 22, not bad for a stock 4x4. Have any of you had any experience removing the turbo charger from a 6.5? Is there more to it than removing the turbo and changing the manifolds and precups? I don't do a lot of pulling so power is not a factor. I am looking at a 98 4X4 in need of an engine, but am not excited about the mileage of the TD's.

[ttpost]

Hi guys , i havent been on for awhile , due to no need lol, lucky me , working on another 6.5 with same crack issues, i need the dimensions on the sleeves, for some reason , even though im logged in , when i click on the link for the crack repair, it takes me to a screen wanting my pw and log in , when i enter it , it doesnt accept it. If someone could post the dimensions of the sleeves i need to repair the cracks between the valves i would greatly appreciate it . ty in advance

[ttpost]

Sorry if im double posting this , i dont see my post from yesterday, I am repairing cracks between valves on another 6.5 , i cant access the section where it has the dimensions of the sleeves i need . Not sure why i cant pull it up, but if someone could post the dimensions for my i would really appreciate it , and ty in advance

[More Power]

...the dimensions of the sleeves i need . Not sure why i cant pull it up, but if someone could post the dimensions for my i would really appreciate it , and ty in advance

It appears your subscription has expired. To re-new (https://thedieselpage.com/form.htm):

Otherwise, here are the dimensions:
.404" valve guide reamer
.375" X 2.5" X .030" bronze valve guide liner

Jim

[riverview]

Hi guys, I'm in the UK and currently rebuilding an 82 6.2. I really want to open the link above but I cant!

[a5150nut]

Try this

https://thedieselpage.com/form.htm