| Slant Six Forum https://slantsix.org/forum/ |
|
| Bore size https://slantsix.org/forum/viewtopic.php?t=61045 |
Page 1 of 1 |
| Author: | ZDCollins225 [ Thu Apr 20, 2017 6:58 am ] |
| Post subject: | Bore size |
I have a 1979 225 in a d100 and a 1980 225 in a ram trying to figure out which one else will be better to build both run but looking to get some extra torque how far can I bore it before the walls get to thin |
|
| Author: | Dart270 [ Thu Apr 20, 2017 10:02 am ] |
| Post subject: | |
0.060" is no problem at all. Some people have gone over 0.100", even up to 0.200", but on earlier blocks. I would do 0.060", most likely. You will not gain much power from this alone, but it can help unshroud the valves if you use bigger valves in the head. Lou |
|
| Author: | coconuteater64 [ Thu Apr 20, 2017 10:58 am ] |
| Post subject: | |
My philosophy is "When in doubt, go with the oldest block and newest head" when dealing with a slant six. That's my $0.02 on it. You really won't gain much performance boring a slant out as far as it will go. It's better to bore them the least amount possible so you can rebuild them a couple more times. |
|
| Author: | Reed [ Thu Apr 20, 2017 11:09 am ] |
| Post subject: | |
As has already been mentioned, nothing much is gained by overboring a slant six. I second the arguments that ou should overbore only enough to clean up the bore and/or unshroud oversize valves. .060 is plenty overbore for oversize valves. |
|
| Author: | ZDCollins225 [ Thu Apr 20, 2017 11:56 am ] |
| Post subject: | |
Thanks guys I think I'm gonna go .020 or .030 over and mill the head like .090 then over sized valves and stronger Springs |
|
| Author: | Reed [ Thu Apr 20, 2017 12:00 pm ] |
| Post subject: | |
Instead of picking random numbers, you should do the math to calculate the dynamic compression ratio to find out exactly how much the head should be milled. You will be better off in the long run. |
|
| Author: | DusterIdiot [ Thu Apr 20, 2017 6:01 pm ] |
| Post subject: | Yep... |
Quote: You really won't gain much performance boring a slant out as far as it will go. It's better to bore them the least amount possible so you can rebuild them a couple more times.
Correct.Quote: Instead of picking random numbers, you should do the math to calculate the dynamic compression ratio to find out exactly how much the head should be milled. You will be better off in the long run.
This is also correct.If you are putting together a torque build with a short cam, you need to make sure you have your measurements and math down... nothing chaps worse than not having enough compression to support the cam, or too much and no matter what you do, it rattles until it knocks a hole in the piston. If you are going for a streetable torque build... and using an RV style cam like the OCG 819, you need to make sure you have min 9:1, but no more than say 9.3:1 to properly support the upgrade. Also to make more torque in a useable range, you have to advance the cam when you degree it in... but... there is a limit... here again, you will need your measurements so you can run the DCR calculator and make sure you haven't over advanced it... Also since these cams have a bit more lift over stock, doing head work... cleaning up the ports and matching the runners will help make gains as well... After that, a little more carb and exhaust makes the next bump... Better rear ratio also helps get things motivated better... |
|
| Author: | Killer6 [ Fri Apr 21, 2017 6:31 pm ] |
| Post subject: | |
Well, everybody has missed this so far, the very first question You need to answer to Yourself & ourselves is..............what fuel do You want to HAVE to run. If You have no problem always fillin' 'er up w/premium then there are many things to enhance torque & efficiency. If You'd like to get by day to day on regular, You'll have to play it conservative. |
|
| Page 1 of 1 | All times are UTC-08:00 |
| Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/ |
|