HE vs flathead and acceptance of boost pressure.
#161
Alcohol will outcool any intercooler, I've seen alcohol do 90 degree temps whereas a good intercooler only got it down to 120. I'm talking total advance. As far as my 1000hp claim, I've seen e85 make 1.47x the hp 92 could make. Maybe 1000 is too far, at least 900. But no thanks, I couldn't afford that entire situation.
#162
I still stand by the fact you need to double the ring end gap if you’re going to turbo any engine. I remember doing that to mine. When I put those two Saab turbo’s. On it.
It’s been bothering me though. So I finally dug up my old notes it’s .015 stock and opened up to .030. Not .150 opened up to .300. Sorry.
It’s been bothering me though. So I finally dug up my old notes it’s .015 stock and opened up to .030. Not .150 opened up to .300. Sorry.
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#164
Alright! Figured out my ring gap. Going to go to increase it by .002" per many pistons manufacturers. Really wish I didn't have to pull pistons out, but hey, gotta do what you gotta do.
Let's talk head gaskets! What are some good options? Definitely need something thicker to drop compression.
Is it even worth time to maybe port the heads a little at home? Like removing casting flashing?
Let's talk head gaskets! What are some good options? Definitely need something thicker to drop compression.
Is it even worth time to maybe port the heads a little at home? Like removing casting flashing?
#165
Join Date: Jul 2010
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Jonathan-W (05-01-2020)
#166
Well, by this websites definition of "build". I'm not building it because I'm not going to poor $30k into endless custom parts. Right now I'm putting money together to go and buy a 93 xj12 for it's motor. I do need guidance on where to find some thicker gaskets. I know for sure that I want to do a higher octane tune at some point and push some higher pressures, and it's not knock that compression causes it's just the load it causes on the bottom end. Plus I need insight on how much I should do with the he heads to improve them, if it's worth it at all.
#167
#168
Alright! Figured out my ring gap. Going to go to increase it by .002" per many pistons manufacturers. Really wish I didn't have to pull pistons out, but hey, gotta do what you gotta do.
Let's talk head gaskets! What are some good options? Definitely need something thicker to drop compression.
Is it even worth time to maybe port the heads a little at home? Like removing casting flashing?
Let's talk head gaskets! What are some good options? Definitely need something thicker to drop compression.
Is it even worth time to maybe port the heads a little at home? Like removing casting flashing?
I suppose piston mfg. would tell you that. They want to sell pistons.
the trouble with thicker head gaskets is that moves the camshaft further away from the crankshaft new chains and sprockets are pretty tight.
Not sure you can put much thicker gaskets on without custom chains and or sprockets.
Thicker gaskets might also move too much and be easier to blow. A lot of the racers went to cooper rings. ( gas filled hollow rings set into a groove cut into the cylinder.
Remember the basic rules. Air has mass. When you force mass to turn you decrease flow.
Look at the flow of the early pre HE head ( also called the Flathead )
and compare it to the flow of the HE
In the Flathead the valve opens up and air swirls (caused by the angle of the intake port. Right into the cylinder as the piston is going down. When the piston comes up on the compression stroke the flat flanges Of the piston forming the combustion chamber ( Huron head) in the piston create squish forcing a turbulent mixture of air and fuel into the center of the cylinder where the spark plug is on the Flathead.
Compare that with the HE head. Open the valve and the air has to curve to get past the recess the intake valve is sitting in. Then as the piston comes up the fuel air mixture is forced over the hot recessed exhaust valve before it can squirt over to the spark plug. That heat will increase the tendency to preignition.
instead of the flame front being centered over the piston it’s focused on one side of the piston. Adding drag and decreasing net horsepower.
Finally the ports are free of casting flash. There is room for opening up the ports and still retaining the angle that gives swirl. But it’s a massive undertaking. Only rarely does hand porting actually increase flow and then only by a very skilled and patient person. I
typically spent 200 hours getting the same flow in all 12 intake ports. since you’re limited by flow from the stock intake manifold 200 hours of work tends to yield very little unless you are using alcohol which increases the fuel mass significantly. ( about 60% more than gasoline if you’re using E 85. ) nearly 100% more if using methane.
If you have a big enough vertical mill you can use a ball mill and at the right angles reduce the porting time down to about 20 hours or so.
Last edited by Mguar; 05-01-2020 at 01:23 PM.
#169
Alrighty great then. I have no problems not taking time to port. One thing I'm going to have to stand firm on is my ring gap claim, I'm pretty sure there's more turbo Honda's out there going by that rule that never had Piston gap issues. But I will do some more reading into that, you could be right. Also, I looked at some ignition numbers for other motors, our timing for our cars isn't entirely different. My w8 passat with 10.8:1 was at 25 degrees at wot at redline, so close to the Jag. And as far as head gaskets, I see two different thicknesses, .040" and .060". Which one is stock? And do you have some documents on stock ring gap?
#172
Join Date: Jul 2010
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you should buy Total Seal rings , they are much better than factory Jag , they are made for forced induction engines!
i have used them in many engines! MG probably never even held one in his hands!
ron
i have used them in many engines! MG probably never even held one in his hands!
ron
Last edited by ronbros; 05-01-2020 at 03:35 PM.
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Ivan Hall (05-01-2020)
#173
Swear to God man if I do all this work just for it to blow up, I don't know what I'll do. I'll be real mad. I'll do total seal. At that, I'll need to research what kind of crosshatch my bore needs to have, because I'll be using a motor with 50k miles. Hopefully I won't need any machine work.
#174
Maybe I'll do total seal later. Don't know. https://www.jegs.com/i/Total-Seal/901/S1444/10002/-1
I don't think it's worth it in the short term. Maybe I'll do it later if it holds together. Yeah I'll do total seal after I put some miles on it.
I don't think it's worth it in the short term. Maybe I'll do it later if it holds together. Yeah I'll do total seal after I put some miles on it.
#175
Alrighty great then. I have no problems not taking time to port. One thing I'm going to have to stand firm on is my ring gap claim, I'm pretty sure there's more turbo Honda's out there going by that rule that never had Piston gap issues. But I will do some more reading into that, you could be right. Also, I looked at some ignition numbers for other motors, our timing for our cars isn't entirely different. My w8 passat with 10.8:1 was at 25 degrees at wot at redline, so close to the Jag. And as far as head gaskets, I see two different thicknesses, .040" and .060". Which one is stock? And do you have some documents on stock ring gap?
Regarding gasket thickness all I have are new gaskets. I don’t keep old trash. So I have nothing that is already compressed. I do know that you won’t have enough gasket to try to use HE pistons on a Flathead. Do the math. The Flathead has 0 cc combustion chamber and the valves when seated stick proud of the head. How much depends on what was done at the last valve job.
The HE head does have a combustion chamber so you can do the math and calculate what putting a 6.0 head on a 5.3. Will yield.
Documentation is based on Haynes manual page 21. About the middle of the page under Piston Rings
#179
What I didn’t like is when the air filtration system failed and some track debris got in the Hilborn injectors. The rings couldn’t finish a 30 minute track session. Without pumping out enough oil to get the car black flagged. Regular rings would have held up at least long enough to finish the race. When I pulled that engine apart not only were the rings bad the cylinder walls didn’t clean up and needed new sleeves and new pistons.
You can fairly say that it was the fault of the air filtration system. But that was all we had room for. And when it had failed in the past a hone, new rings and the engine was back together.
I’ve built and raced enough cars to know that things seldom go according to plan. I’ll trade a few horsepower for a season of racing.