johnnyCZ

I'm going to have my heads repaired:
- resurfaced
- valve job + new hardened exhaust valve seats
- spark plug thread repair

My engine is 100% stock but I'm running LPG (butane gas) which is quite popular here in Europe for cars with larger engines due to it's half-price when compared to gasoline. It is little bit similar to E85 when it comes to ideal compression ratio. But it can be aggressive to valve seats as it burns in higher temperatures, doesn't contain any aditives and is dry.

My question - if I have the heads milled to 0.02 inches, will I need to reprogram anything? Is this a safe number without needing other modification? I will use stock gasket size.

Thanks!

1FastBrick

iTrader: (17)

You will most likely need to change the valves out. GM did LPG conversions on the LQ4 engines under the RPO code KL6 The heads had different valve seat, as well as different Intake and Exhaust Valves for the LPG.

If you're not already on LPG you will probably need some type of Injector data for it to run properly.

I have not seen an LPG tune Vs. a standard gas tune so I couldn't say for sure.

bobfig

imo .02" would need to be looked at for tuning as your bumping the compression from around a 9.5:1 to 9.9:1. it may run fine but i would still at least data log it.