High compression high RPM 7M-GE build
- Thread starter andrew_mx83
- Start date
Quin;1996863 said:
Ah, I didn't know that. By the time I came around here and had my Supra I don't think he had a Supra anymore. I feel like I missed out on something.
Silver MK3;1996868 said:
IJs build thread was... huge, instructive, occasionally funny, overflowing with car part/shop porn, and... huge. I would even say legendary.
multiple built heads, multiple turbo setups, MOTEC with LPG and custom injection stuff... I liked that it was all function first, form second.
But I don't think he likes a lot of attention. He'd prefer we stay off his lawn.
Anyway, while I'm in here, nice build! I like the fabrication.
Poodles;1996915 said:
Good question. Im going to deal with the blowby gasses straight out of the crankcase, it is 'positive CRANKCASE ventilation' after all. I cant really see the need to bring the blowby gasses out of the block, and into the front of the cam cover only to pull it out the back of the cam cover again. I also dont see how there would be any blowby generated in the head itsellf. I plan to run a hose from the fitting on the block to an external oil header tank/catch can/air separator/fill point.
Ill probably fit a temporary pressure gauge to the head and block to make sure nothing is amiss with this setup but i think it will work fine. I actually end up with more area this way than the 2 pissy outlets on the factory cam covers anyway.
RPM wise i will turn it to 8500 and if it is still making power maybe 9000, but no higher. Not on a 91mm stroke, not when you do the math on piston speed. 10k rpm is well PAST hand grenade territory IMO.
Yeah LPG is great fun, ive been running it for years. It has a bad name here in oz because most people set it up wrong so the car drives like shit, but you cant beat it for octane, and setup right it goes very well. Plus it's half the price of regular unleaded... I'd love to go down the ITB + liquid LPG injection route, but it is a lot of $ and i would much prefer direct injection into the chambers than the ports, so more development is needed first. Ill stick with my trusty Impco 425 carby for now.
A little more progress on the build, i got the crank washed and installed for hopefully the last time. I went through 5 litres of Prepsol washing the block, and another litre on the crank.... i do like to work clean
I also started to make a new retention plate for the auxiliary shaft but unfortunately didnt get it finished before i had to go out for the night so pics will have to wait a couple of days...
Oh yeah, what are people doing about Eagle rods and no squirters? With no lube hole in the big end i cant see a lot of oil getting to the pin, or even the bores for that matter. The small ends have 2 holes drilled, but i dont imagine they will do much without oil squirters.
^ one of the reasons I'm running squirters so my pauters will get oil.
You do not need pcv vents on the cam covers but routing pcv to the head has its advantages. It mainly helps push oil back down to the block.
Sent from my SPH-L720 using Tapatalk
You do not need pcv vents on the cam covers but routing pcv to the head has its advantages. It mainly helps push oil back down to the block.
Sent from my SPH-L720 using Tapatalk
andrew_mx83;1997088 said:
NegativeGeForce;1997090 said:
Think the spray out of the big end when its at the top of its stroke is enough to soak the cylinder walls, then have the oil ring push it on the pin? I am currently on eagle rods and forged pistons and was wondering if I could delete the squirters, but I'm worried about pin oiling. I was so close to having the spray hole drilled into the eagles but never did.
You could machine a notch on the side of the rod in line with the stock rod oil holes, Have seen this done on Pauter's, I ran squirters with mine and made sure Hot idle was 40+ Psi.
This sounds like a good idea, probably easier and better than drilling.IJ.;1997147 said:
The argument for squirters doesnt stack up for me. I dont like the idea of taking precious oil away from the bearings to 'cool' the pistons... remember that physics tells us you cant actually cool anything down, all you can do is transfer its heat energy somewhere else. Id rather ceramic coat the pistons and keep the heat energy in the chamber, where it can be converted to horsepower, instead of using it to heat up my oil.
Negative crankcase ventilation would be nice, but not nice enough to run a smog pump! I usually just vent my cam covers to atmo anyway...
Seeusmile, whereabouts in Melbourne are you? Im in the outer east, near all the good driving roads
Cant wait to take the car up into the hills to break this motor in. Im just crossing fingers that the gearbag doesnt explode on that first drive!
Oil squirters are worthless when running forged pistons when N/A or boosted, but for a motor that is gonna see 30-40psi of boost...its extra insurance. The only way heat can transfer away from the piston is through the tiny area of the piston rings. Even though forged pistons can take alot more heat there is still a point where you're putting more heat in than you can take out. Those squirters are going to be useful when a motor is doing sustained high boost levels like in a time attack.
I ran a heat dispersant coating on the under sides of the Pistons as well as a big oil cooler as my cars see long pulls at maximum power.andrew_mx83;1997190 said:This sounds like a good idea, probably easier and better than drilling.
The argument for squirters doesnt stack up for me. I dont like the idea of taking precious oil away from the bearings to 'cool' the pistons... remember that physics tells us you cant actually cool anything down, all you can do is transfer its heat energy somewhere else. Id rather ceramic coat the pistons and keep the heat energy in the chamber, where it can be converted to horsepower, instead of using it to heat up my oil.
Negative crankcase ventilation would be nice, but not nice enough to run a smog pump! I usually just vent my cam covers to atmo anyway...
Seeusmile, whereabouts in Melbourne are you? Im in the outer east, near all the good driving roads
Cant wait to take the car up into the hills to break this motor in. Im just crossing fingers that the gearbag doesnt explode on that first drive!
andrew_mx83;1997190 said:This sounds like a good idea, probably easier and better than drilling.
The argument for squirters doesnt stack up for me. I dont like the idea of taking precious oil away from the bearings to 'cool' the pistons... remember that physics tells us you cant actually cool anything down, all you can do is transfer its heat energy somewhere else. Id rather ceramic coat the pistons and keep the heat energy in the chamber, where it can be converted to horsepower, instead of using it to heat up my oil.
Negative crankcase ventilation would be nice, but not nice enough to run a smog pump! I usually just vent my cam covers to atmo anyway...
Seeusmile, whereabouts in Melbourne are you? Im in the outer east, near all the good driving roads
Cant wait to take the car up into the hills to break this motor in. Im just crossing fingers that the gearbag doesnt explode on that first drive!
Yeah i'm in the suburban west Area. Probably not as much cool roads at your end XD.
I dont feel like there's been a heap of progress, but i found a bunch of photos on the camera that make it look like there has been:
Late model GE block is ribbed and studded, for my pleasure
Shit cleaned and ready to go in
Crank hole cleaned and awaiting crank
Crank in the crank hole
Journals were ground and linished to 7Ra, galleries cleaned and plugs reinstalled/peened over, balanced
All buttoned up to 80ft/lb +/- 0.5 ft/lb (love the digital torque wrench). Oil clearances set @ 0.0015"
New aux shaft retention plate is not quite finished, still need to machine in some oil feeds to the bearing. Takes a Koyo roller thrust bearing which will be much better than relying on an unlubricated steel on steel bearing surface to take up the axial load. Direct replacement for the OEM retention plate.
Half assembled
Assembled
In the block, waiting on collar
Late model GE block is ribbed and studded, for my pleasure
Shit cleaned and ready to go in
Crank hole cleaned and awaiting crank
Crank in the crank hole
Journals were ground and linished to 7Ra, galleries cleaned and plugs reinstalled/peened over, balanced
All buttoned up to 80ft/lb +/- 0.5 ft/lb (love the digital torque wrench). Oil clearances set @ 0.0015"
New aux shaft retention plate is not quite finished, still need to machine in some oil feeds to the bearing. Takes a Koyo roller thrust bearing which will be much better than relying on an unlubricated steel on steel bearing surface to take up the axial load. Direct replacement for the OEM retention plate.
Half assembled
Assembled
In the block, waiting on collar
Also got some shorter studs for the cam caps, and chamfered off the nuts which has helped smooth out the look.
Starting to see the visual effect i'm going for, hopefully in the car you will clearly see the "air path" for each of the 6 cylinders going from intake runner, intake cam, spark plug, exhaust cam, exhaust primary. I should pull my finger out and make the other one.
(note this is a pretty good representation of the port offsets on the inlet side. The studs are the dead centerline of the cylinder, you can see by the runners how far off the port entries are. The exhaust ports however are perfectly centered over each cylinder and all except #1 are exactly the same -#1 is only a bees dick different anyway, around the water gallery for the thermo housing)
Starting to see the visual effect i'm going for, hopefully in the car you will clearly see the "air path" for each of the 6 cylinders going from intake runner, intake cam, spark plug, exhaust cam, exhaust primary. I should pull my finger out and make the other one.
(note this is a pretty good representation of the port offsets on the inlet side. The studs are the dead centerline of the cylinder, you can see by the runners how far off the port entries are. The exhaust ports however are perfectly centered over each cylinder and all except #1 are exactly the same -#1 is only a bees dick different anyway, around the water gallery for the thermo housing)
good grief man, I find myself coming in this thread about one a day and just staring at those cam covers...they just look so aggressive! I'm like a bug in front of one of those zapper lights.