Hello, Ok got some major issues Just had a 2003 GT 4.6 2 valve with P.I. heads rebuilt .010 over so now its a 284 C.I. Machine shop fitted JE flat tops and we now have a comp ratio of 12:1 Think they were thinking of non PI heads which would have netted me a 10.5:1 C/R Motor has comp cams 102100 cams, Typhonn intake manifold Accufab Plenum and throttle body BBK equal length headers C/A intake Engine tuner cannot tune it with 91 octane fuel. Without overheating or piston knock( car has a 3 core radiator high flow pump fans coming on @ 180 with a 180- T stat ) and still runs hot ( 240+ degrees) I see the only option is to increase the head gaskets to .080 which would net us a 10.7:1 comp ratio Thought of putting on some Trick flow 44CC heads but still wouldn't net us the compression ratio below 11:1 Everyone says not to run octane booster for a continuous time talked to VP they said not to or couldn't run water w ethanol injection . Dont really want to go with E85 due to the [problems with fuel lines or if it sits for weeks n weeks. Only 2 options pull the entire motor out and have it re done and fit 7 C.C. JE pistons in it or do the gaskets, any other options you guys may have would be great! Feeling like i got F'd!!
03 GT 4.6 2 Valve new engine issues
- Thread starter Oh3GT
- Start date
Its possible to move the coolant to much and the overturn be to hot, like the radiator cant do its job because the water flow is to much. If you can measure temps coming directly from radiator exit, ideally ambient temperature is what you want. If its 90degree in the work area, close to 90degree radiator exit is what you want. Now comes in the thermostat adjusting. That a whole different topic. Check your radiator exit temperature 1st.
Also like most engines ever made, there are dead areas within the engine that water becomes stagnant with flow such as hot spots. Not a problem for most factory untouched engines. Luckily the modulars heads have water port access covered with freeze plugs. Look for the head cooling mods or build one of your own. It transfers water from the rear of the heads to the front. This helps tremendously with the rear 4 and 8 cylinders and balances water movement across the heads for a more consistent temperature.
If the car isnt driven much and you dont mind mixing fuels, grab a gas can that seals tight full of E85 and each time you fill the car up, add some. You may not need the full E85. Perhaps E40 or E20. And also your car is E85 compliant meaning all the fuel components are capable of withstanding the E85 destruction, but i get what youre saying about the fuel sitting for months such as the insides of fuel injectors.
Also like most engines ever made, there are dead areas within the engine that water becomes stagnant with flow such as hot spots. Not a problem for most factory untouched engines. Luckily the modulars heads have water port access covered with freeze plugs. Look for the head cooling mods or build one of your own. It transfers water from the rear of the heads to the front. This helps tremendously with the rear 4 and 8 cylinders and balances water movement across the heads for a more consistent temperature.
If the car isnt driven much and you dont mind mixing fuels, grab a gas can that seals tight full of E85 and each time you fill the car up, add some. You may not need the full E85. Perhaps E40 or E20. And also your car is E85 compliant meaning all the fuel components are capable of withstanding the E85 destruction, but i get what youre saying about the fuel sitting for months such as the insides of fuel injectors.
OP, I did a little chemistry math for you. You owe me one, I really dislike messing with ratio calculations.
Drop 2 gallons of ethyl or isopropyl alcohol (90% or better, this is for 99% isopropyl) in the tank for every 12 gallons of 91 octane. That'll give you effective octane of ~95 which will be just fine on 12:1 compression and the cost is a pittance. Your tuner will need to adjust the stoic AFR to deliver 8-10% more fuel. Make sure he's got a wideband on and understands about mixed fuels. The stoic AFR with the mixing ratio noted will be closer to 13.8:1 rather than the normal 14.7:1
It's a lot cheaper than you'd think. https://www.beautyzonesupply.com/products/9c?variant=32375061119079
Sure it's $25 more a tank to fill it but you'll be making pretty killer power for a 2v.
Drop 2 gallons of ethyl or isopropyl alcohol (90% or better, this is for 99% isopropyl) in the tank for every 12 gallons of 91 octane. That'll give you effective octane of ~95 which will be just fine on 12:1 compression and the cost is a pittance. Your tuner will need to adjust the stoic AFR to deliver 8-10% more fuel. Make sure he's got a wideband on and understands about mixed fuels. The stoic AFR with the mixing ratio noted will be closer to 13.8:1 rather than the normal 14.7:1
It's a lot cheaper than you'd think. https://www.beautyzonesupply.com/products/9c?variant=32375061119079
Sure it's $25 more a tank to fill it but you'll be making pretty killer power for a 2v.
So can you mix the E fuels with 91 Octane? or is it 100% either or? Is the 2003 set up from the factory to run E85? or has to be redone for all the hoses? Problem is that i see is with the E 85 it takes approx 30% more fuel than does 91/ regular fuel so the system would have to be set up to accommodate that... Im thinking it might be running so lean that its running hot. no way should it get tat hot that quick in the city or highway / Thoughts?
lunch is on me hahaha Thanks would have never thought about it! Ill run it by him just seams weird to add but if it works! the Car should pop n run like a rabab tigar!
I’m kind of curious why he’s having issues with it. I ran my 2v at 13:1 on 93 octane and never had an issue. Daily drove the car like that.
Did he build the engine to specs you gave him, or how he wanted to build it? Either way, I really feel like you’ve got other issues. Compression has never made my cars run hot.
Compression typically doesnt cause problems untill load comes into play also timing plays a major factor. I learned alot when i did that 18:1 5.4l 2v. My biggest issue besides failed oil control rings was hot spots of the engine ie poor cooling system while running 93 octane. Once to temperature it would idle up out of control. When flushed out and filled up with E85, their was no comparison....night and day difference.
I just cant picture it moving that much quicker in that short amount of time to cause an issue. It did it with a high flow pump and a sindgle as well as a dual radiator on a 100% dayin 5 miles as well as in stop n go and on the freeway
Ok perhaps its a lack of fuel causing it? Im in the process of getting an A/F wide band gauge installed to see what it is
Are you sure your radiator isn't clogged up, OP? Mine clogged 100% on my 01 Cobra. I only found out because instead just barely warming up when I got home from work it was way way too hot and I couldn't squeeze the upper radiator hose. A 20 year old car is bound to have some scale built up inside the rad. Try replacing it.
engine has just been rebuilt, radiator, fan, water pump are all brand new, so im lost
Ok this is 100% a stupid question, but i gotta ask......is the cooling system burped? Meaning no trapped air? is the upper radiator hose hot as well when up to temp?
