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twin cam motors

Posted: Fri Mar 23, 2007 7:33 pm
by groupAralliart
I am getting a few parts together and on the lookout for parts. My question is: Is there a better twin cam 4g63 motor to buy? I understand the 6 bolt crank is the basic first step to choice? yes/no? Is a non turbo motor a good choice (lower temperatures during its life etc) and is there any difference between the mitsubishi 4g63 and the korean proton/hyundai (can't remember the exact brand but you know what I am talking about) 2.0 ltr motors. I saw 3 at a wreckers this week and I don't know if it was a standard price or a good deal but the complete motor (non-turbo) with 3 month warranty for $425 was offered. What have you guys paid? I as many, simply (I hope it is!) want to run a twin cam head and MPI on my Starion 4g63 block. Advise welcome. Steve :?

Posted: Fri Mar 23, 2007 8:07 pm
by www.18u
It really depends what parts your after.A Hyundai may be ok for things like pulleys but the vr4 engine was designed for a turbo and this means things like the oil pump would be bigger and most likely a different type of piston and camshaft profiles (correct me if im wrong) A Hyundai engine will run a higher compression ratio and also won't have oil squirters in the block.If you want to build a hybrid (starion/Hyundai) then i guess you could use the Hyundai head and pulleys and timing cover and just use a vr4 oil pump.Also a Starion has a shorter crank than a vr4 not to mention a different bolt pattern.Keep searching but in my opinion go with a vr4 if you want to go twin cam or do what i did and go starion/vr4 hybrid.

Posted: Fri Mar 23, 2007 9:46 pm
by toysrus
Just to clarify this once and for all, the VR4 Crankshaft (IE FWD/AWD Engines) are the same length as the Starion RWD Crankshaft. I know on some Mitsubishi RWD Cranks, they feature a 'long nose' but not the Starion Crankshaft, so a FWD or AWD 6 Bolt Crankshaft is a drop in affair :beer

www.18u, different bolt pattern ? Actual Galant VR4's only came with 6 Bolt Flywheel Engines......

Posted: Fri Mar 23, 2007 9:54 pm
by groupAralliart
From what I understand the bottom end I have (Starion 4g63) will be kept and the twin cam head bolts on (I understand there are a few mods)
and you use the twin cam pulley system. Correct? I simply want to know if things like the non turbo twin cam head is suitable , is there any difference in port size / designs and which would be the best (COST/AVAILABILITY/OPERATION) inlet MPI manifold to use from a standard mitsubishi motor eg a magna or L300 or evo or vr4 or non-turbo twin cam? Thanks Steve

p.s. I also hear that I should maybe go the whole hog and put a 2.3/2.4 strocker crank in but I have also heard that pistons are an issue in that conversion?

Posted: Fri Mar 23, 2007 10:20 pm
by www.18u
No worries thats why i said correct me if im wrong.I looked through some of my photos when i built my motor and i now can recall that the timing gear on the vr4 is much thicker and if you use the balance shaft gear aswell the large centre balancer bolt will not make enough thread contact with the starion crank.I can email the pic if you like as i cannot seem to find the upload on here anymore.

Posted: Fri Mar 23, 2007 10:52 pm
by RiceThief
If you go the stroker with a twin cam, wiseco have forged pistons designed for a stroker kit that will sort out the piston problem.

As for manifold you would have to use the twin cam one from a vr4 or possibly the gsr. Also i think there are some jap import 4g63 that have cyclone on them which is suppose to be a superior design to what we got with the vr4. You will also need to modify the manifold to make the tb face the right way.

As for using the non turbo cams, i believe you might be better off as the non-turbo cams would have more lift and duration that the turbo cams.

Posted: Sat Mar 24, 2007 7:42 am
by ROCKETMAN
Im running a similar set up, Hyundai 4g64 timing gear, head and crank, pre-fitted everything , seems to be no issues so far.
Got it all cheap too from a late model sonate (black top head).
Custom wiseco pistons and rods is all thats needed, cheaper than getting similar mods done to a sr20det :wink: .

Posted: Sat Mar 24, 2007 7:57 am
by isnowi
4g63 dohc N/T and turbo are very similar, main differences being pistons/rods, only 1 of the cams is different (can't remnember which), and the turbo block has oil squirters installed, whereas N/T only has the untapped bosses for the squirters. Ports are the same size across N/T and turbo heads, oil pumps the same (unless you happen to find a motor thats been fitted with an aftermarket HF pump) All other differences are confined to boltons.

Feel free to add to this, I'm only going off my own experiences.

(also this all relates to 6 bolt motors)

Posted: Sat Mar 24, 2007 11:04 am
by groupAralliart
Thanks guys, I would like to spend the money once, do it properly and keeping the single cam head might save money now but I know down the track a twin cam head is the best option. I will have the engine built to perform in street sprints (Gatton, Speed on the Tweed etc and sprints out at Morgan Park/QLD Raceway) so horsepower is important but so is torque and strength. I can not afford to rebuild it again.

Posted: Sat Mar 24, 2007 11:47 am
by RiceThief
groupa - out of interest who are you going to get to build it?

Posted: Sat Mar 24, 2007 5:13 pm
by groupAralliart
Have two choices but have not ruled out the possibility of doing it with my fathers help (he was the S.A. and QLD Mitsuishi service manager so knows a thing or two about them as well as being an A grade mechanic.) Dad has been retired for a while now, infact one of the last JD Starions was one of his company cars (I remember we used to get a new car about every 5 or 6 weeks), I can still remember when dad bought the first JA home and as a 15 year old trying to reach boost before I reached the end of our long driveway - I still can not believe dad let me drive all those cars. One Sunday I drove the press release L300 4wd into a post ripping the passenger side panels. All the pics had to be taken from the other side, I will never forget the look on dad's face - he actually witnessed the 'incident'. Realistically though I hope Redzone might wave his wand. I have a widebody arriving up here next week, I have a JA sitting in a mates shed with a good motor (forged pistons) and later this year hope to put the package together (I have to sell my Charger before starting). Cheers Steve

Posted: Sun Mar 25, 2007 9:12 pm
by groupAralliart
so what is a good price for a twin cam motor or head and intake manifold?

Posted: Mon Mar 26, 2007 6:32 pm
by greenstaz82
isnowi wrote:4g63 dohc N/T and turbo are very similar, main differences being pistons/rods, only 1 of the cams is different (can't remnember which), and the turbo block has oil squirters installed, whereas N/T only has the untapped bosses for the squirters. Ports are the same size across N/T and turbo heads, oil pumps the same (unless you happen to find a motor thats been fitted with an aftermarket HF pump) All other differences are confined to boltons.

Feel free to add to this, I'm only going off my own experiences.

(also this all relates to 6 bolt motors)
Hey man the port sizes are defernetly different bettween non turbo and turbo , non turbo is smaller and rounder in shape compared to the bigger oval shape on the vr4 turbo galant heads . ive heard late model evo's are diffrent again with a smaller port .

Posted: Mon Mar 26, 2007 7:12 pm
by redzone
i just picked up a galant VR4 engine thats been overheated, to build a similar combination for my JB after the gem's done. i will be using the starion bottom end with the VR4 head and accessories, as i will also be using the RX7 gearbox conversion which needs the wide pattern block. i paid $300 for the engine which is minus exh manifold/turbo and injectors, its rumoured to have a set of aftermarket cams in it too, will find out soon enough.

i've seen only big port heads on VR4 engines, seen big and small ports on NA motors, and small ports on EVO1-3 motors. best bet is to pull off the intake before u part with your cash.

i'm probably gonna stay with the 2.0 capacity with mine, want more rpm capability than a really long stroke engine will provide. and steve i'd love to do your work :beer

Posted: Mon Mar 26, 2007 7:27 pm
by groupAralliart
Sounds like you have all the bits and pieces I need. How about I slip the widebody (will have to come up with a name for it : maybe 'brutus' - a name dad used on one of his funny cars. Any other suggestions, it is black also) into your work shop and you get it all sorted?