cylinder head mods 4 cng conversion

[Ric Havel]

Good morning,
New to your forum.
I am looking for info on the necessary modifactions required to properly convert 2008 GMC Truck gasoline 6.0 V8 vin K engine/heads to properly operate on CNG. I operate an automotive machine shop and have been asked by a Gas Co. to convert several of their new 2008 GMC Truck 3/4 and 1 ton trucks w. 6.0L vin K. The extent of my involvement will be to convert the aluminum OHV cylinder heads to allow use of CNG. They have done such conversions on 2006 trucks with no monifactions to the heads and tell me the valve seats recession reared it's ugly head within 50,000 miles. I understand I may need to change seats, valves and valve guides and re assemble. Can anyone shed any light on this conversion/specs/suppliers? I don't want to do too little to the heads nor do I want to change more parts then required. Please reply any help will be appreciated.
Ric

[Curtis]

First off, I'm going to move this thread over to the Conversion forum. I would start by reviewing threads in that forum that may give you a lead on the info you seek.

There is a list of EPA certified conversions listed in that area as well. These may resolve your problem and I hope some of the more technically oriented folks here may jump in and offer you some help.

[darress]

Ric,
Here is an interesting link I ran across with some clues to what the 6.0L engine requirements for the cng system are. You could check with a GM dealer on what the specifics are on the LQ4 and KL5 options. http://www.nyne-ngvp.org/pr_2006/pr_02_23_06_baytech.htm
Darress

[Ric Havel]

Hello Darress,
I would like to thank you for the reply.......I thought maybe my question was displayed in the wrong language or sent to another planet from the lack of replies. I will research this option and once again thanks.
ric:)

[neongreen]

I'm no expert, but hardened seats and stainless steel valves are never a bad thing. And while you are at it, raising the compression ratio will make them more efficient. I have no idea who would be a good supplier for valve seats, guides or valves, you would just have to look around on that one.

[CanAm]

Valve seat recession seems odd on newer vehicles because since the advent of unleaded gas all cars have used hardened valves and seats. We used to do a lot of conversion on older engines from the 60's to allow them to run unleaded.

[neongreen]

How they are hardened can differ though. On my truck which is a 1988 the seats were just hardened by heat treatng that area of the combustion chamber. That meant that once the valve seats burned, there was no more hardening, since the hardening wasnt very thick. So I had the machine shop install some hardened stainless steel valve seats. Now aluminum heads always have an insert, but often it is made from powdered metal, and I dont think that is the optimum high-heat valve seat.