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Location:
Brisbane
Registered:
October 2002
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5MGE/7MGE
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Thu, 17 October 2002 09:21
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Can anyone tell me if a 7MGE 24v head will fit on a 5MGE bottom end. I'm looking for the capacity of the 5MGE for a class of racing. As they share the same bore size I thought I might be able to take advantage of the 24 valve head's flow, with the capacity I need. I assume I would need to use the timing case from the 7mge as well.
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Location:
c'town, NSW
Registered:
May 2002
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Re: 5MGE/7MGE
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Thu, 17 October 2002 09:28
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dunno if this helps but i know u can put the 5M-GE head onto the 7M block, the american Mk3 supra enthusiasts do it and call it the 57M-GTE, do a search for it on the web might find some info that'll help.
hope this helps
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Location:
Brisbane
Registered:
May 2002
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Re: 5MGE/7MGE
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Thu, 17 October 2002 11:14
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Yes it can be done, the bores are the same and all the water and oil galleries line up.
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I supported Toymods
Location:
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Registered:
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Re: 5MGE/7MGE
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Fri, 18 October 2002 03:41
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Yes it will fit, but:
check pistons....5MG pistons are hightop, whilst 7MGE pistons are slightly dished and have flycuts for the valves. Apart from likely valve clash with pistons, your compression ratio will be astronomical.
You could run 7MGE pistons in your 5M (same bore and piston pin diameter is 22mm) but you'll need to check the compression height of the 2 pistons - I think there is 0.2 mm diff (32.7 vs. 32.5mm) but you will need to check on the ACL online piston catalogue. If that is the case you will need to deck your 5M block by 0.2mm. In the past, you could get flat top 5ME pistons - these would have been ideal as you could have just got them flycut and there would have been a healthy increase in compression. ACL 5ME pistons are dished  .
Also you will have timing belt and timing issues....I have never counted the teeth on the crank or cam gears of either, but you should be able to swap one over for the other - the crank gear just presses on. Tensioner mechanism will also need to be considered. No idea which is best. I'm assuming if you're racing you will want adjustable cam gears - they are available for the 7M.
What class of racing? Can't you go 7MGE or even 2JZGE? If the class is that restictive, will they allow the 7MGE head, given the 5MG was only a 2 valve per cylinder? Does the 7MGE head ACTUALLY flow better than the 5MG head - in other words have you tested them both? You might be suprised - the exhausts are generally VERY restrictive. If porting of the head is allowed, go the 7MGE head, but if it isn't, definitely spend the $100 to check the head flows.
Sounds interesting - let me know how you go.
Cheers Dave.
[Updated on: Fri, 18 October 2002 04:21]
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Location:
Brisbane
Registered:
October 2002
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Re: 5MGE/7MGE
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Fri, 18 October 2002 08:34
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Thanks for the information guy's.
At the moment I've got a 7MGE in my race boat (hydroplane). The long motor is rebuilt standard with triple webers and extractors. With the 7MGE it is in 3750cc class. The idea with the 5MGE/7MGE hybrid is to offset machine the crank (destroking) and have a shot at 2750cc class (the 5MGE is 2759cc). I'd like to make the current 7MGE my club racing motor, while I use the hybrid for major days.
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I supported Toymods
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I renounced punctuation
Registered:
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Re: 5MGE/7MGE
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Fri, 18 October 2002 09:07
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Wow, OK! Sounds like an out there 7M. Love to see pics!
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Location:
Lost in the K hole
Registered:
May 2002
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Re: 5MGE/7MGE
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Fri, 18 October 2002 14:34
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youd never believe that ive been thinking of making a play motor to basically the same specs!
(dave, dont trash the mte yet!!)
i'd be very interested to see how you set up the triple webbers!
ed
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Location:
Brisbane
Registered:
October 2002
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Re: 5MGE/7MGE
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Fri, 18 October 2002 22:15
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When I started with this I couldn't find a manifold to suit the webers for the 7MGE, so I had it custom made. We decided to use webers instead of injection because of the restrictive manifold fitted as standard. I'd get better inlet flow with individual throttle bodies (like a sprintcar), but the cost was prohibitive to have that custom made. Besides the inlet manifolding and exhaust, the motor is standard.
The classes are based on capacity only, although turbo's, etc get a penalty. So I'm free with modifications so long as its normally aspirated and under 2750cc.
The main reason for staying with the M series motor was they use the same engine mounts, I'm told the JZ series are different. I haven't compared head flow, I guess I'd assumed the 4v would flow better. I'll put some pictures up when I work out how. The boat can be seen as it used to be at www.ignitedesign.com.au/NSWHC , just look at the boat profile page then look up livewire.
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Location:
c'town, NSW
Registered:
May 2002
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Re: 5MGE/7MGE
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Fri, 18 October 2002 23:41
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the guy who owns the boat diablo (Dave Warby) used to frequent these forums, i bought a motor from him a while back, and he was putting in a 1JZ into his hydoP, looked like a aweseome little machine you guys must have a ton of fun...
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I supported Toymods
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Registered:
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Re: 5MGE/7MGE
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Sat, 19 October 2002 08:14
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Seeing as you have the triple Weber manifold already made, you could easily go multi-throttle body injection at some later stage. Of course, you will need an aftermarket ECU to run the show.
I didn't realise the classing system was totally different to cars...I thought it might have been 2000 - 3000cc - which is why I suggested 7M or 2JZ. If you destroke to 84.7mm, you'll get to just under 2750.
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Location:
Perth
Registered:
August 2002
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Re: 5MGE/7MGE
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Sat, 19 October 2002 16:30
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WTF? yanks *actually* remove the 24v head and fit the 12v one!?!? HAHAHAHahhahhahahaha LOllolool. only in america..
I'm extremely interested in the 7m head on the 5m tho. That would be severely awesome! imagine the Higher flow of the 7mg head combined with the shorter stroke of the 5mg!! yee hawwww@2@!
Gianttomato, are you sure that the piston-valve clearance will be a problem? I would have thought that the 5mg would run more lift than a 7mg look at the size of those cam towers! Also, what would you estimate the CR to be using OEM 5mg pistons? the 5mg has fuck-all compression standard.
I reckon the ma61 community should test and DOCUMENT this conversion A.S.A.P. A 24 valve 5mG?!?! Flows and revs better!!?!? Gimme gimme gimme!!
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I supported Toymods
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Registered:
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Re: 5MGE/7MGE
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Sun, 20 October 2002 02:21
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| RollaLevin wrote on Sun, 20 October 2002 02:30 |
Gianttomato, are you sure that the piston-valve clearance will be a problem? I would have thought that the 5mg would run more lift than a 7mg look at the size of those cam towers! Also, what would you estimate the CR to be using OEM 5mg pistons? the 5mg has fuck-all compression standard.
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RollaLevin, I'm almost 100% certain - I haven't done it but knowing what both pistons look like, I would imagine the valves will hit the 5MG piston. The cam towers on the 5/6MG are just one way of storing the cams and hydraulic mechanism to open the valves. The 7MGE works by direct cam to bucket activation, hence no need for huge towers. Can't comment on the 5M lift, but 7M would have around 7.5 - 8 (or so) mm.
Standard 7MGE CR is 9.2:1 and that's with a piston that is DISHED. Put in a piston that is DOMED and you'll send the CR thru the roof!
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Location:
Lost in the K hole
Registered:
May 2002
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Location:
Lost in the K hole
Registered:
May 2002
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Re: 5MGE/7MGE
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Sun, 20 October 2002 12:28
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| gianttomato wrote on Sun, 20 October 2002 12:21 |
Standard 7MGE CR is 9.2:1 and that's with a piston that is DISHED. Put in a piston that is DOMED and you'll send the CR thru the roof!
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yeah GT but the question is: even if you got a domed, or even flat 5m-e piston for eg, id be feeling a little uncomfortable machining out 4mm of material for the 4 valves... thats not going to be good for the piston
i fell bad having to knock 2.0mm out of mine
cheers
ed
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Location:
Perth
Registered:
August 2002
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Re: 5MGE/7MGE
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Mon, 21 October 2002 14:39
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Thanks GT. You're a living fountain of toyota knowledge 
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: 5MGE/7MGE
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Fri, 25 October 2002 00:08
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I rang Wade Camshafts and they suggested 5MGE cam lift might be 0.221" (5.6mm), although they're not 100% certain.
Also I did some prelim calcs which suggest that the CR might be conservatively around 13.5-14:1, too high for pump fuel.
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Location:
Brisbane
Registered:
May 2002
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Re: 5MGE/7MGE
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Fri, 25 October 2002 03:20
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Sounds like the perfect excuse to run the bastard on methanol! 
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Location:
Brisbane
Registered:
October 2002
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Re: 5MGE/7MGE
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Tue, 05 November 2002 09:08
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Guy's, sorry I haven't been on for some time. I've been kind of busy for the last couple of weeks getting ready for a major race in Bundy. I appreciate all the advice on my subject. I'm not sure yet if I'll go through with the project as I've been made an offer to swap for a brand new bigger boat.
The motor (7mge) never missed a beat all weekend, even starting first time nearly every time with direct drive (as in no neutrals in gearbox).
It was a little weak in the top end, but with only small venturi's in the carby's and very tall prop and gears it's no wonder.
Thank's again.
Dave
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Location:
Princeton, NJ
Registered:
October 2002
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Re: 5MGE/7MGE
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Wed, 06 November 2002 06:10
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| rob_RA40 wrote on Thu, 17 October 2002 05:28 |
dunno if this helps but i know u can put the 5M-GE head onto the 7M block, the american Mk3 supra enthusiasts do it and call it the 57M-GTE, do a search for it on the web might find some info that'll help.
hope this helps
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no we don't! I've never even heard of this, in 3 years!
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
|
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Location:
Lost in the K hole
Registered:
May 2002
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Re: 5MGE/7MGE
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Wed, 06 November 2002 06:36
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yep, was about to say (dave beat me AGAIN!) very common mod indeed.
ed
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