2.5 compression and fuel

**ActivatedSludge** · 10-04-2012, 05:09 PM

Would 155# of compression work with 93 pump gas. (With standard timing, box set at 102) 1997 2.5 260 offshore
Thanks, Kurt

**Fasprop** · 10-04-2012, 06:04 PM

Kurt I sent you an email a while ago... Talk to you later. 102 is plenty fat.

**Jay Smith** · 10-04-2012, 07:28 PM

As long as the fuel was VERY fresh, the ambient temps were warm, high humidity and the timing was say 23 155 cranking at sea level should be OK, if all those moon and stars didn't line up you could be in trouble..

Jay

**patchesII** · 10-04-2012, 07:31 PM

Also depends on prop/load

**ActivatedSludge** · 10-04-2012, 08:14 PM

Thanks guys, I'm going to double check compression tomorrow with a Snap on gauge. My gauge is a cheap one, numbers are all close, I am just suspect that they are a touch high. This was also a cold engine, shouldn't the #s be a touch higher on a warm engine? Kurt

**racerx** · 10-04-2012, 08:39 PM

Numbers will go down on a warm motor,like 5 lbs...all the oil sittin in cylinders cold gives a higher reading...

**YELLOWSS** · 10-04-2012, 09:30 PM

Originally Posted by patchesII

Also depends on prop/load

Eric is correct when you start running custom fuel curves, and watching egt temps.. It doesn't take long to figure out the bigger the wheel the leaner it is going to get........ Add some weight does the same thing.......... Better be careful......JMO

Roy

**Dave Strong** · 10-04-2012, 10:21 PM

Living on the edge for sure, and the gaines compared to to the the damage ain 't worth it. JMO. As Jay said if everything is bang on your good to go, but if not. Going to get $$$.

Dave

**stoker2001** · 10-04-2012, 10:26 PM

doesnt EGTs rise when you retard max advance timing below 25*?
mine are pegging 1250* these days with box at 104% 165psi cranking on 65/35 AV100/91pump
90 degree ambiant air temps

**Dave Strong** · 10-04-2012, 10:31 PM

EGT's can fool a guy, do piston wash and plug checks first and get a baseline. Temp on EGT's are not a good way to base things, after you get plug and piston wash OK you can use the EGT#'s as a warning.

Dave

**YELLOWSS** · 10-05-2012, 12:13 AM

Originally Posted by Dave Strong

EGT's can fool a guy, do piston wash and plug checks first and get a baseline. Temp on EGT's are not a good way to base things, after you get plug and piston wash OK you can use the EGT#'s as a warning.

Dave

That is correct.......

**ActivatedSludge** · 10-05-2012, 05:24 AM

Will the thicker gasket do or should I look for a set of heads that have not been cut? Kurt

**ActivatedSludge** · 10-07-2012, 03:32 PM

False reading on cheap gauge, snap on gauge reads 145. Thanks ! Kurt

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