Ltngjim Posted October 9, 2013 Author Share Posted October 9, 2013 I already applied the altitude factor to the compression numbers (essentially adding 20%). The actual numbers from the guage were around 90 dry and 110 wet. Lots of ALL CAPS. Guess I hit a nerve here. Quote Link to comment Share on other sites More sharing options...
NewZed Posted October 9, 2013 Share Posted October 9, 2013 (edited) These numbers point to worn rings, which requires an overhaul. My gas mileage hasnt been too bad (~20 MPGs on a commute at 50 MPH) and the power seems to be sufficient. Is there any danger to running the engine in the condition and doing an overhaul at a later date? The nerve might be that you're blindly following general suggestions from the FSM or some other source, possibly leading to unnecessary work. There is no "requirement" to do anything. You're free to make your own decisions. You say the engine runs well, gets decent mileage, and has sufficient power, but you're still talking about doing work and spending money to get numbers on a gauge. A kind of a bureaucratize mentality, in a free-thinking forum. It sounds like you're waiting for someone to chime in and tell you to rebuild, but it's probably not going to happen. In post #8 I linked to a thread about a large volume head on a dished piston motor. What engine are you working with? You never said. Get the head numbers and the block numbers and see if it looks like it's been messed with (new gaskets, etc.). Who knows, you might have P79 head on a dished piston block. That might explain the lack of response at low RPM and the low numbers. Don't get offended, it's all part of the learning process. Get some more data and come back. Edited October 9, 2013 by NewZed Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 9, 2013 Share Posted October 9, 2013 That is about the dumbest thing I can think of someone doing when asking for advice. You would think you would give us the readings you got, not something you pulled out of your arse. Good luck wasting your money. The answers you get directly reflect the questions asked. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 10, 2013 Share Posted October 10, 2013 I already applied the altitude factor to the compression numbers (essentially adding 20%). The actual numbers from the guage were around 90 dry and 110 wet. Lots of ALL CAPS. Guess I hit a nerve here. I will say it again, and I am in Denver, same altitude. I don't blink an eye at those numbers, and I dynoed 313rwhp with a L28ET with the same compression numbers, between 105psi and 110psi. It runs well without burning a lot of oil, don't "fix" it. Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted October 15, 2013 Share Posted October 15, 2013 I'm in Albuquerque (roughly the same altitude ~1mile.) and my readings were between 100 and 115 across all 6 cyl. My engine ran okay, but the AFM was messed up, causing issues. Could have been my thermotyme, in anycase it was okay for a year before I started my swap. Sold the L28 as good and never had a complaint, they swapped it into a Zzzap and it's still driving around. Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted October 15, 2013 Share Posted October 15, 2013 Sounds like the motor that was in my ZZZAP. About 110 on all six. My AFM was also rigged, if it was even the same one. Quote Link to comment Share on other sites More sharing options...
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