Increasing compression - Need scan help, please view!
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Originally Posted by 95naSTA
Originally Posted by big_news_1
we need to remove .040" of material from the heads. That should put compression around 9.8:1
It has been reported that the LN3 had 8.5:1 compression, and the L27 had 9.0:1 compression, which I feel is not correct, but its possible...
The LN3 was rated at 165 HP and the L27 was rated at 170...
Just a question.... Not knocking anyone....
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From: Glendale, AZ
The guys at Delta took a horizontal measurement on the base circle of the lobes, from the 3 o'clock to the 9 o'clock positions. This measurement yielded a .080" reduction in base circle diameter, which translates to a .040" reduction in base circle radius. This is the number we needed, and Doug got it by calling Scott at Delta. The cam won't be here until Tuesday, so we didn't want to wait until then to read the spec sheet and get the heads milled.
Jr, you may be right..... this might only gain us a couple of ponies. However, if we couple it with increased spark timing, it should give us a nice bang for the buck. Don't forget, the heads are also gasket-matched and polished, so we're expecting decent numbers.
I might try to do a baseline dyno despite the car'* issues. I would really like to know much power I'm putting to the ground in current form. If the gasket fails completely, I'll just shut it down, drain the oil, and call a tow truck. No harm, no foul!
These next few weeks should be exciting!
Jr, you may be right..... this might only gain us a couple of ponies. However, if we couple it with increased spark timing, it should give us a nice bang for the buck. Don't forget, the heads are also gasket-matched and polished, so we're expecting decent numbers.
I might try to do a baseline dyno despite the car'* issues. I would really like to know much power I'm putting to the ground in current form. If the gasket fails completely, I'll just shut it down, drain the oil, and call a tow truck. No harm, no foul!
These next few weeks should be exciting!
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From: Appleton, WI
It has been reported that the LN3 had 8.5:1 compression, and the L27 had 9.0:1 compression, which I feel is not correct, but its possible...
The LN3 was rated at 165 HP and the L27 was rated at 170...
Just a question.... Not knocking anyone....[/quote]
The L27 pistons are approx. .050" taller above the pin than the LN3. There is some difference in the dish but it is an easy way to pick up compression ratio in an LN3 rebuild.
The LN3 was rated at 165 HP and the L27 was rated at 170...
Just a question.... Not knocking anyone....
[/quote]The L27 pistons are approx. .050" taller above the pin than the LN3. There is some difference in the dish but it is an easy way to pick up compression ratio in an LN3 rebuild.
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From: Glendale, AZ
Originally Posted by MyLittleBlackBird
According to 95nasta, with .040" off the heads, we'll be looking at 10.19:1, not 9.8:1. See page 3 for details.
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Don't make me go CC these heads...
Also, regarding the previous post....
P.*. Heads checked out. Got milled .040". Took .010" off each side of the intake. We should be golden. If not, RTV will save us!
Also, regarding the previous post....
Originally Posted by 2seater
There is some difference in the dish but it is an easy way to pick up compression ratio in an LN3 rebuild
P.*. Heads checked out. Got milled .040". Took .010" off each side of the intake. We should be golden. If not, RTV will save us!
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Originally Posted by llBlazin_llLo
I think he is talking about RTV'n the LIM gaskets where the LIM meets the heads.
