High compression high RPM 7M-GE build

andrew_mx83

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#1
Hi guys, thought i should start a thread about the new engine i'm building for my Cressida (yeah yeah, its not a supra, but close enough!)
For those that dont know, 7m's are kinda my thing, GE's in particular. I'm not really into turbos.
What i do like is a nice responsive high rpm NA screamer, which built properly the 7m-ge is quite good at.
The motor will be run on dedicated LPG (Propane) which is great as the 110RON out of the bowser means you can run silly compression and it loves ignition timing. Not to mention it is cheap as chips here in Australia and allows a lot of the EFI crap to be deleted from the engine.

Let's start with the head. Last year i bought a big new milling machine which i converted to CNC, and i wanted to CNC port a 7m head. There was so much f'ing work in coding this up, and a lot of machine time for the actual porting!
Being only a 3 axis CNC i cant get absolutely everywhere in the ports, but i was able to work on the important bits, being the valve bowls and combustion chambers. Still, being CNC it has one very distinct advantage in that each port/bowl/chamber is exactly the same as the next. Also it beats the hell out of spending 40 hours with your die grinder....
All the machining work was done concentric to each valve seat (or port)



The intake ports were left alone past the bowls as they are already too big, however the exhausts were opened up by 1mm at the port exit to maintain a reversion dam, and this bigger diameter was carried back to where the 2 valves join into 1 port which according to my cross sectioning was the most restricted part of the exhaust port.



you can sort of see here how much meat was taken out of the mid-port area


end result without valves


with valves



While we're on the exhaust side, remember that pesky EGR hole in the #6 exhaust port, normally blanked off by a plate on the rear of the head in ADM cars... well that's gone now.


as in completely gone, i press fit a plug in the hole before milling out the port and the extra bits of plug were cut away with the rest of the port....




The chambers were actually left with the standard cloverleaf shape to maintain squish, but the shrouding around the valves was heavily cut back. I did a 3 angle valve job and the 3rd angle then leads into a large radius into the chamber. The radius is in fact the same as the valve radius so in theory maximising the flow without removing more meat than necessary (cant loose to much comression!)

So here is the original chamber, complete with valve shrouding. at low lift in particular they are quite restricted, with max lift not a lot better TBH



New chambers and bowls. The seats were bored out 2mm and again there are some funky radii going on in the bowl. The valve guides were also milled with an aerofoil shape on the inlet to split air around the valve stem, and create a low pressure point behind it which is otherwise a dead area of the port. a simple chamfer is enough on the exhaust.






An idea of the various curves and arcs involved in the valve bowl toolpath. No CAM, the code was all written in MS Excel
 

andrew_mx83

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#2
I did some other work while the head was up on the CNC as well.

Firstly the water galleries -usual missing #6 coolant drain was added, but i have also tried to address the airlocks inside the head by milling out the pockets so that the air cannot get trapped in this area.




Originally those passages come out around 3mm off the roof of the pocket, meaning air bubbles can get trapped in that remaining area and there is no path for them to escape upwards and be burped out at the radiator filler. Now they are basically just at the roof of the pockets so there is no stagnant areas.


I have also added ARP insert washers to go under the head studs. These press fit into the head and the idea is to stop the head bolt hole caving in around the stud and allowing the head to lift. More an issue on soft heads but still good insurance even on a rock hard head like this one.

Milling out the press fit


Washers installed




I had a lot of time staring at the head while it was on the CNC so i got bored and chased every thread in the damn thing (except spark plugs, still need to buy a tap) which is really nice when assembling stuff, all bolts go in by hand then just need half a turn with a spanner and they are tight.


Head all machined and ready to assemble





Installing valves, and heavy duty springs. Took this all apart again as i have changed over from OEM 2jz valves to Ferrea stainless 7m ones in 1mm OS





Still need to reassemble with the new valves and set lash, but the head is mostly complete. Ive got some 280* x 8.5mm cams to go in it, adjustable gears, shim under bucket conversion and some other goodies.

Oh, i also milled a good chunk (ie >2mm) off the head chasing moar compression, probably unnecessary now with the pistons im going to use, but oh well at least it will run on diesel if need be :)
 

andrew_mx83

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#3
My new cam covers are still a long way from finished, but you get the idea. I only just test fitted it on the head properly for the first time today! They were designed to be as slim as possible and also NO LEAKS. No rubber gaskets to get squished "just right", no juggling the torque on bolts ~300mm apart to not bow the covers but still get a seal, these are studded through each cam cap and when it all bottoms out there will be a .5mm gap off the head for FIPG. Do the nuts up, wait for the FIPG to dry and never worry about it again :)

They are basically only just tall enough to clear the front cam cap/cam seal and are relieved underneath to clear the cam lobes.
Why lumpy cam covers? Because lumpy cams!

I need to get some shorter studs as they look a bit funny atm, but they are noticeably slimmer than stock









 

andrew_mx83

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#4
Today was a nice day to be working out in the sun so i final washed the block, gave it a quick lick of paint and dragged it inside into the engine building room. Also drilled/plugged it for front sump and plugged the main oil gallery between the pump and filter which i wont be using anymore.
block was bored & honed to 1mm OS while "stressed" with torque plate, main caps etc and surfaced with the minimum amount off to get a good seal around the bores (0.011")







 

7M4EVR

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#7
After going to a turbo I've never understood why the average guy would spend a bunch of money to build up a NA. However, clearly you are not the average guy haha. Nice work. It will be cool to see how this all comes out for sure. Good luck!
 

suprarx7nut

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#8
Neat to see all the machine work. Keep the pics and info coming!

Sent from my XT1060 using Tapatalk
 

IndigoMKII

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#12
Will you be building a crank girdle for the mains as well? Use billet mains and extended main studs that tie into the girdle to keep the 7m crank from being a wet noodle at the RPMs this thing might see.

Also, you can do like IJ did and use an electric water pump with the 7mge water pump to keep cavitation from happening at high RPMs.
 

Rollus

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#14
This is awsome job!

Really nice work on the head.. I did some similar mods (except port job):
- Quake's mod: ARP insert washers (pending, need the correct drill bit and tool, the machine shop ask really too much to do that with CNC)
- EGR gallery plug
942506_10202817158300617_2080370446_n.jpg 1528604_10202817157980609_412529698_n.jpg
- Zooloo's mod: opened 6th cylinder water gallery
1011737_10202817159700652_1608169752_n.jpg 1609767_10202817159260641_1198320638_n.jpg

My headwork is not comparable to your, which is soooo clean !
 

NegativeGeForce

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#15
And I thought I did a crazy 7M head. I guess I gotta step it up next time.



I love the machine work you've done. This thing is gonna turn out awesome. You obviously have been doing this for a while.
 

AbsoluteSpeed

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#16
Can't wait to see how this pans out. Some really impressive fab skills going on here.
I hope a set of ITBs make their way onto this. Guess I'll have to wait and see.
 

andrew_mx83

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#17
Thanks for the comments guys.

No crank girdle for this one. Ive never had the crank become a "wet noodle" before, you keep the bearing clearances tight and lots of oil up to it and the engine will feel as smooth at 8000rpm as it does at idle. Main bearings arent something you see a lot of fail in these things. B/E's sure, but not mains.
This motor has ARP main studs as an upgrade, i normally just run OEM bolts in an NA motor.
The engine this one is replacing turns past 8000rpm on a "stock" bottom end with ARP rod bolts and some oiling upgrades. I actually built this CNC head to go on that motor, but it didnt quite fit so here i am building a new bottom end for it as well.


I have an electric water pump here, but not for this engine. Im saving that for the dry sumped/destroked race motor that i hope to one day finish.
The genuine water pumps have a steel impellor which seems much more resilient to cavitation than the aftermarket cast ones.



7M4EVR -Sure, NA vs turbo is never going to stack up in $/kw, but going fast isnt all about peak horsepower...
 

andrew_mx83

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#18
Oops, missed a couple of replies!

Rollus, might i suggest you measure all the insert washers with a micrometer and order them by size before you start. i found the press fit section had a pretty wide tolerance, so i graded them by size before i started which makes it easy to maintain a good fit.


Negativegeforce i was looking at your build thread, very impressive! Will be taking some pointers for the 1000rwhp GTE i am building for a customer of mine :)
I built my first 7m 10 years ago, i was just musing yesterday how many have been on that engine stand since... ive literally lost count!
Ive only been in the machining game for a few years, but i really enjoy it. I run a small aftermarket parts business, Technico Racing, where i make shiny billet stuff, mainly for Toyotas. Most of the custom parts going to this build are or will be available on the website once i get time to update it.


Absolutespeed, no ITB's just yet. Maybe one day, with liquid propane injection. I do have a new manifold and throttle setup to go on this, but it's probably not what you're expecting...
 

Silver MK3

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#20
This is really cool. I don't think I've ever seen a 7M running on Propane. Keep us updated, I like all the pictures of the machine work too, very cool.
 

te72

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#23
I'm not on here as much as I used to be, but it's good to see people still playing with the NA setups. Do us all a favor and get a good microphone for when it's running well? :D
 

miekedmr

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#25
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.
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.
 

andrew_mx83

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#26
How are you going to handle PCV?
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...
 

andrew_mx83

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#27
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.
 

NegativeGeForce

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#28
^ 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
 

Bmettie

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#31
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
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.
 

IJ.

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#32
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.
 

andrew_mx83

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#33
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.

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!
 

NegativeGeForce

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#34
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.
 

IJ.

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#36
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!
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.
 

SeeUSmile

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#37
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.
 

andrew_mx83

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#38
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
 

andrew_mx83

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#39
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)
 

7M4EVR

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#40
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.