Hello All, this is my first post, please be gentle if I have done it wrong.
I am going to replace my 2nd gen 12 valve 190HP (currently) valve springs
I have watched several videos and read several articles about how to change these with the head on the vehicle. They all mention applying air to the cylinder to prevent the valves from falling into the cylinder.

It seems to me that if I put number 1 into TDC that I could just use the "popular spring compressor" without the possibility of the valve disappearing on cylinders 1 and 6. Then rotate the engine a fairly precise 120 degrees and either do 2 and 5 or 3 and 4, depending on which way I rotated the engine.

I don't think the valve could fall in enough so that it would prevent taking the keepers out.

Or am I mistaken ?

While you are here, I am doing the basic mods to up the 190HP to approx 350HP. From what I understand the Allison 545 will self destruct. Does anyone have experience with this? I am happy with the trans and the 8K + cost of going to a 1000 is just to much work, cost, for the unknown end result for me. if I could do some mods to the 545 I think that would be the way to go

Thank you, and sorry in advance ;-)

Mikekstitzel
1994 RV, Cummins 12 valve, 4k governor, 191 delivery valves, #10 plate, afc mods, 60# valved springs, turbo waste gate fitting, egt pyro (as soon as i can find an electric one)