I'm with Tim. Make sure the engine is warm. Something else I've seen is dislodged carbon from the plug threads throwing off comp tests. On a good hot engine, redo both tests. Also, how much oil did you put in? Too much and you're just reducing chamber volume, which will push numbers way up. Also, as Tim said, where is the air leaking from on the leakdown? That is the utility of the leakdown test, it tells you "what" is bad. The bad thing is that no test I'm aware of will tell you anything about oil ring condition, but you say you're not using oil.
Bill Cardell TurboDog's Dad www.flyinmiata.com www.fmwestfield.com orders 1-800-FLY-MX5S tech support 970-464-5600 Don't miss Flyin' Miata's Open House! Aug 14-17, 2008 ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tim South Sent: Tuesday, June 10, 2008 5:01 AM To: Dillon; miatapower List Subject: Re: turbo a motor with less than perfect compression? Dillon, What is your leakdown saying you should do? Your wet compression test indicates rings. That's alot of ring wear for 70k I think. Was your leakdown test hot or cold? If cold, repeat hot and listen for where the air is going. ----- Original Message ----- From: Dillon <mailto:[EMAIL PROTECTED]> To: miatapower List <mailto:[email protected]> Sent: Tuesday, June 10, 2008 1:21 AM Subject: turbo a motor with less than perfect compression? I've posted on and off about my engine "troubles" so I apologize if any of this is repeated. I have a 99 10AE that just tipped 70k miles. I'm planning to add a turbo (specific kit / parts not yet determined) with a Megasquirt ECU for engine management. I plan to start at around 5-6psi and upgrade from there. First step is to get the MS wired up and working, then I'd like to add the turbo. However, before starting anything, I checked the compression on the motor and did a leakdown test that showed leaking around the rings. * Dry/hot Compression: 175 - 152 - 150 - 175 * Wet/hot compression: 200 - 187 - 180 - 205 * Leakdown: 25% - 35% - 35% - 10% I am not using any appreciable amount of oil now, and the car seems healthy (aside from the numbers). I was shopping for a replacement block, or a reputable shop to rebuild the bottom-end, but it's been suggested that I should just turbo the motor that I've got, and deal with the engine rebuild in the future. Considering my low (initial) power goals, how much of a gamble is this? If I could squeak out 6-12 months on this motor before it started using lots of oil, I'd be a happy camper. What do you guys think? Any experiences boosting a motor with numbers like mine? ________________________________ _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
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