4M Performance package - Suggestions please.

[TheToyman75]

GT,

I actually just sent a 5M-GE to the scrap metal recyclers last week. I really want to use a 4M block and am loath to bore it out to 5M or 6M/7M specs asI do not want any head gasket concerns.

I posed the question in case like iwth T series engines there was a pick of factory cames, heads, blocks and cranks that gives a good result for minimal investment.

I have already nought a set of the factory twin downdraft carbies for it, complete iwth air cleaner and throttle linkages. I just have to have them posted from Japan early this year.

Extractors were dealer optional for most vehicles and are acceptable for historic rego. So at this stage I think it will just be picking up a good 4M block and pistons and giving it a rebuild. A minor cam perhaps and aim for 9.8 - 10.1 compression. Just got to decide on what head to use but I guess I will wait to see which head the carbies will bolt too. I have both of them "lined up" as well.

Looks like it may just take a little actual research.

If it wasn't on Historic rego I was actually thinking 4V powered as a preference. I need to keep my eyes out for another one of those. I should have kept the last one.

[Gavatron]

From memory the only pick of the heads would be early 4M or earlier with the separate head bolts and rocker gear bolts, as opposed to the late ones with them combined.

You probably already knew that though.

I have a 7M you can have if you want it. And my old Crown that Sean has will not be needing it's motor I am assuming. Tha old thing made 62rwkw through a slipping converter with just 5M elec ignition and a 2.25 inch exhaust through the stock manifold. Doubt Sean would want much for it.

Freight would be the only hassle.

[gianttomato]

Hmmm...Rod I wouldn't count on terribly much more than 80 rwkW. My 4M with ported head, upped comp, cam, triples and extractors made mid 80s rwkW. 100% gay considering the 2JZGE made nearly double that with not terribly much more outlay.

Problem is all this shit is exxy to rebuild - might as well use all the good bits to make a decent 3 litre SOHC M motor. Can't see why 100+ rwkW wouldn't be achievable.

Why so wedded to the 4M block? Mill off the 5M engine number and stamp your 4M engine number on to it if it means so much to you!!

Also before you get carried away, I'm sure you know the early and late SOHC M have different intake and exhaust port and bolt spacings. Your twin downdrafts will only fit on the earlier style heads.

[TheToyman75]

GT,

Historic rego means must be the 4M. And I don't really want to cheat the system.

I am not chasing big numbers, just more than the 30rwkw odd I am expecting this Dyno day. will the carbs fit on either an early 2M or an Early 4M ?? If so I can stick with the model correct 4M head which again would be nice.

[cambelt]

Yes the carbs will fit both heads . If you want to stay 4M , find yourself a 71 MS65 crown
4M with the black 4M sticker on the rocker cover ,also head casting 11111-41030 , these make 150 HP acording to the motoring write ups of the time .
All that aside the early MS65,s go very well , much better than the 73 and 74 models with the red 4M sticker.
Dave

[Gttwinturbomk3]

Yes the carbs will fit both heads . If you want to stay 4M , find yourself a 71 MS65 crown
4M with the black 4M sticker on the rocker cover ,also head casting 11111-41030 , these make 150 HP acording to the motoring write ups of the time .
All that aside the early MS65,s go very well , much better than the 73 and 74 models with the red 4M sticker.
Dave

Are you sure that your not getting mistaken with the 3m? 150hp is a hell of a lot from a 4m

[rob]

my History of M engines article i wrote about a billion years ago (yeah i know there are some errors in it)

anyways check out the engine data tables FYI on comp ratio and hp

http://users.tpg.com.au/users/loats/.../mhistory.html

its interesting to notice how much some of the engines have been choked by EFI and emissions gear giving a drop in power.

[cambelt]

I agree totally,150 HP sounds like bull from a 4M , Id say more like 135HP.
Some 15 years ago i did a 5ME conversion into my mark II , I didnt need a engineers certificat at the time because the 5ME made less power than the 4M did.
It was my engineer that found out as he had a motoring magazine with the early MS65crown in it .
Dave

[thechuckster]

fwiw: the MS75 referred to in Norbie's post is for sale.. the specs are:
"It has Dual DD 180cfm Weber/Holly Carbies on a 4M-D Factory Manifold, a 7M Crank and Rods and is bored to 83mm with Forged pistons and 10:1 CR. The Cam is by Ivan Tighe, rebuilt and reground to give around 200hp."

[tomvale13]

I'm showing my housemate this thread - his 2m is fucked.

(subscribed)

[TheToyman75]

fwiw: the MS75 referred to in Norbie's post is for sale.. the specs are:
"It has Dual DD 180cfm Weber/Holly Carbies on a 4M-D Factory Manifold, a 7M Crank and Rods and is bored to 83mm with Forged pistons and 10:1 CR. The Cam is by Ivan Tighe, rebuilt and reground to give around 200hp."

Chuckster,

This car has been sold.

[thechuckster]

fuckinhell ... that was quick.

[Gttwinturbomk3]

I have seen a 4m over here a while back with flows and twin carbs put out 58kws. Which was not bad also it had 2.25 exhaust and the carbs where solex ones it made its max power at about 5000rpm i think.

[Gavatron]

My stocker MS65 made 62rwkw through a slipping converter with just 5M elec ignition and a 2.25 inch exhaust through the stock manifold.

[Gttwinturbomk3]

My stocker MS65 made 62rwkw through a slipping converter with just 5M elec ignition and a 2.25 inch exhaust through the stock manifold.

Yeah i saw that! thats impressive, was its revs at around the 5000 mark? Which i think was what the one i saw made its power at?

Oh i see, you posted dyno sheet awesome

They actually sound pritty cool with flows.