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OK so I just got my new straight edge and feeler gauges and check my piston deck clearance and found its a zero deck. According to all the compression ration calculators I am at 13.05:1 static. Her are the specs.
bore 4.060
stroke 3.75
combustion chamber 54 cc (lt4 heads)
valve reliefs 3.4 cc (L2491F speed pro pistons)
head gasket thickness .039 (felpro 1074)
deck clearance 0
So now my question is what are my options? I realize I can get heads with bigger combustion chambers but don't have $2000+ to spend on heads. I'M not going to rip the bottom end apart and change pistons And right now with the .039 head gasket I have a quench of .039 and I would not want to raise it over .040. Can I run pump e85 in it and if so what do I need to change? I have heard it is bad for aluminum but don't know much about e85. Can anyone pass along any info they have on this especially if you are running e85 in your lt1/lt4 motor.
You could run e85 or e50 only, but that would be a pain in the ***. Some fuel system components would need to be redone (namely lines, filter) to tolerate it.
13:1 is definitely way too high for pump gas unless you have some huge solid roller cam to keep the DCR down. You want to shoot for 8.5-8.7 DCR on 93 octane, any more than that and tuning will be very touchy. https://www.jeepstrokers.com/forum/calculator/
You have 3 options:
-Get a head porter to open up the chambers. Lloyd might be able to take them out to 58cc while unshrouding the valves which would net more power.
-Thicker head gasket. Less than ideal quench isn't the end of the world. It might cost you a little torque and making tuning more difficult, but it'll run fine. Stock is 0.75+ or something atrocious like that.
-Custom grind cam with some ridiculous specs to drop DCR. A Lunati 243/251 (294 adv on the intake) with -4 degrees retard ground in and a 114lsa would give you 8.6DCR at your current SCR. Would be kinda soggy to drive though.
You could run e85 or e50 only, but that would be a pain in the ***. Some fuel system components would need to be redone (namely lines, filter) to tolerate it.
13:1 is definitely way too high for pump gas unless you have some huge solid roller cam to keep the DCR down. You want to shoot for 8.5-8.7 DCR on 93 octane, any more than that and tuning will be very touchy. https://www.jeepstrokers.com/forum/calculator/
You have 3 options:
-Get a head porter to open up the chambers. Lloyd might be able to take them out to 58cc while unshrouding the valves which would net more power.
-Thicker head gasket. Less than ideal quench isn't the end of the world. It might cost you a little torque and making tuning more difficult, but it'll run fine. Stock is 0.75+ or something atrocious like that.
-Custom grind cam with some ridiculous specs to drop DCR. A Lunati 243/251 (294 adv on the intake) with -4 degrees retard ground in and a 114lsa would give you 8.6DCR at your current SCR. Would be kinda soggy to drive though.
Fuel lines don't have to be changed for E85, I've been running E85 on the stock fuel lines for 14 years now, only upgraded the pump, filter, and injectors. Engine is out right now, lines still look good.
I agree though, I would run E85 on this and take advantage of the high compression, either that or get the chambers opened up for a few more cc if you want to stay 93.
Fuel lines don't have to be changed for E85, I've been running E85 on the stock fuel lines for 14 years now, only upgraded the pump, filter, and injectors. Engine is out right now, lines still look good.
I agree though, I would run E85 on this and take advantage of the high compression, either that or get the chambers opened up for a few more cc if you want to stay 93.
I said that because I'd imagine the solvent properties of ethanol could unseat any gunk in your lines/tank and clog up your injectors. The tendency for it to retain water and corrode the inside of the mild steel lines after sitting is also a concern. Stainless hardline or SAE 30R9 (teflon coated) lines aren't that much for a bit of assurance.
I have a walboro 255 fuel pump, and can easily and often replace the fuel filter. So now this is my next question are these injectors 30# svo? And if so will they suffice. 30# svo?
I have a walboro 255 fuel pump, and can easily and often replace the fuel filter. So now this is my next question are these injectors 30# svo? And if so will they suffice. 30# svo?
You need 30-35% more injector for E85 than you would need for the same setup on gas.
I assume I will have to have it tuned to run on e85 correct? If so can I store it in the winter with 110 race fuel and run it with that for the first drive of the next year?
I assume I will have to have it tuned to run on e85 correct? If so can I store it in the winter with 110 race fuel and run it with that for the first drive of the next year?
Yes you will have to tune it differently for E85 since the stoich Air/Fuel ratio is 9.8:1 instead of 14.7:1 like gasoline. So you would have to change your tune between running race gasoline vs E85. If you’re still on the LT1 PCM you have to do this by telling the PCM that your injectors are 30% smaller than they are as a starting point, then adjust it from there using a wideband or dialing in your BLM’s to 128. If you are running an LS or aftermarket computer, you just need an ethanol sensor and tune it for it.
I have a walboro 255 fuel pump, and can easily and often replace the fuel filter. So now this is my next question are these injectors 30# svo? And if so will they suffice. 30# svo?
Pull one of them and look at the shoulder opposite the connector. Should be a batch number, i.e. A 0273, then the part number. If that 8-digit number is 17095004, they're 24#. If something else, look it up. One side of the inlet neck at the connector will have the Rochester RP logo, other side may say something like W 53 or H 30, but that's not the flow rate at 43.5psi...
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compression ratio to high!! 
