no.Sorry to jump on this thread again after a while but can you not deck the head instead of the block to get the correct CR?
12G295 Head - What To Do?
#16
Posted 11 July 2020 - 09:22 AM
#17
Posted 11 July 2020 - 09:44 AM
If a 295 is gas flowed properly there is still a lot to be machined off.
The best thing to do is to first deck the block to bring the pistons right to the deck level and themeasure and calculate how much to remove from the head.
#18
Posted 11 July 2020 - 11:14 AM
Edited by blacktulip, 11 July 2020 - 11:21 AM.
#19
Posted 11 July 2020 - 11:15 AM
I had one doing 9.5:1 with dished pistons. But I agree it's far better to raise the CR anywhere else than off the head face.
#20
Posted 11 July 2020 - 03:54 PM
Yes you can, but it is important to have flat top pistons. If you don't and the piston tops are too far down from deck level at TDC you may have to machine too much from the head and break into the oil way.
If a 295 is gas flowed properly there is still a lot to be machined off.
The best thing to do is to first deck the block to bring the pistons right to the deck level and themeasure and calculate how much to remove from the head.
exactly what we did. engine is a flyer!
#21
Posted 11 July 2020 - 06:01 PM
There's a load of stuff on my YouTube channel regarding 295 heads and calculating compression ratio.
Phil.
Edited by Turbo Phil, 11 July 2020 - 06:01 PM.
#22
Posted 11 July 2020 - 06:02 PM
#23
Posted 11 July 2020 - 06:04 PM
#24
Posted 11 July 2020 - 07:08 PM
Sorry to jump on this thread again after a while but can you not deck the head instead of the block to get the correct CR?
Maybe. While I haven't looked through Phil's Videos, I'm sure he would have covered the potential issue for the Oil Feed to the Rocker Gear, and a work around.
However, I've found that you get considerably better performance from running as flat a top piston as you can (or can find) and getting that as close to the deck as you dare (even protruding) then doing any final adjustments by skimming the head, than running dished pistons and / or leaving anything between the Crown and the Deck of the block and shaving the head to reduce combustion chamber size to achieve the same CR. By building the engine in this combination, you're increase the final Squish volume of the combustion chamber.
1 user(s) are reading this topic
0 members, 1 guests, 0 anonymous users