HELP rebuilding the engine

[Aero-R]

First of all I must say apologyze if something from this post is not understandable, but I'm not english native and I'm not sure about some of the engine part's name on english.


I'm not sure but I think you in Australia get the 4G63T with black valve cover. My Starion came with the 4G63T with red valve cover, and I don't know what differences it makes from the black one but I hope you can give me some advice for my red one. The thing is that my engine has oil leaking. For example: if you go downhill on 4th or 5th gear, without using throttle at all, and then you push it a little bit, it smokes white quite a lot.

I've the luck of being in touch with and old mechanic from Mitsubishi Motors, who raced on rally with a Starion and had 4 units in total, so I'll trust him for the rebuild. The thing is that he's an old man that doesn't use internet at all, so the only market he knows to get the parts is Mitsubishi Motors dealer.

Getting pistons from Mitsubishi Motors dealer is not only expensive, but I've heard also that sometimes you can get better pistons from other markets (and I want the best for my engine), so I don't know if this is fake or not.

At the moment I've bought already the water pump, the spark plugs, a radiator cap and the full gaskets set for the whole engine. Next steps would be getting the complete timing belt kit, full valve set (he suggested me this), pistons and rings (but of course I can't buy those now because we have not opened the engine yet so I don't know what size of pistons should I get), and everything we see damaged once the engine is opened.

The thing is: apart from Mitsubishi Motors dealer there's any place on the world to get better parts (if not same) specially talking about pistons, rings, valves and the head of the motor if needed?

I don't care in which country I should buy, because at the moment buying from the official dealer is expensive (pistons + rings + valves = 2100$), so if with the same money I can get better parts than the official dealer, it would be great. My engine will be for road use only, so not professional racing, just some good speed on road =]

I always found G54B pistons but not pistons for my Starion 4G63T (I've found pistons forsome 4G63 non-turbo and some 4G63T on EVO but I don't know if pistons are the same of if they match with the stock connecting rod or rod (I think that part is called like that, the one that connects the pistons with the crankshaft). I've heard you can't use non-turbo pistons on a turbo 4G63 because one of the 3 rings is different.

I do not have engine/mechanics knowledge, so I know this plust he fact I'm not english native makes a bit difficult this thread, but I hope I can do the best for explaining what kind of engine part suggestions I'm looking for. International market suggestions for pieces that you know will work with the red valve cover 4G63Turbo of my Starion, and/or suggestions for the rebuilding, and/or reviews about if the official dealer parts are better or not... all is pretty welcome since I just want to learn and get it right. Huge thanks in advance.

[John196701]

Aero

I have found this site a while ago, $765usd for Manley forged pistons and H beam rods, they do have forged pistons as well for $490usd

http://realstreetperformance.com/store/ ... 0820766857

http://realstreetperformance.com/store/ ... block-138/

these pistons are for a twin cam with slightly less dish than the standard starion engine, you will end up with a little more compression than standard.

with the piston and rod combination, all you will need to do is bore the block and check / grind the crank and bolt it together. the pistons and rods are full floating and are assembled without needing pressing together.

As far as valves, i fitted manley stainless valves out of a datsun/nissan 200b they needed a little machine for the valve tip height, if i can find the part number, i will add it to another post

[Aero-R]

Great lot of information to start with, thanks John!.

1.- Without taking in mind the money, would you say those parts are better thant he factory ones?

Few doubts more, they are a lot, so I ended with numbers to avoid confusion. Excuse the lot of questions but I'm learning a lot and I want to understand all this world. Lets go:

Aero

I have found this site a while ago, $765usd for Manley forged pistons and H beam rods, they do have forged pistons as well for $490usd

http://realstreetperformance.com/store/ ... 0820766857

http://realstreetperformance.com/store/ ... block-138/

these pistons are for a twin cam with slightly less dish than the standard starion engine, you will end up with a little more compression than standard.

2.- I saw those Manley before but I was afraid they say Eclipse 4G63T, will they work with a red valve cover Starion 4G63T?

3.- I've seen something like 6 bolt or 7 bolt, but as far as I know (I'm not much into mechanic) the pistons doesn't use bolts. So, those 6 bolt or 7 bolt nomenclature goes for...? and which one is the red valve cover Starion 4G63T? six or seven?

4.- Since my engine will be for road use and not competition, will you go with forged pistons? or are those kind of pistons bad for stock engine road use only?

5.- My engine is one single cam not twin cam, I don't know what "dish" means so I don't know if you mean they will work (excuse me, I know terms like bore and stroke, but I don't know what the word dish is on english, sorry!!).

6.- Taking in mind my engine will be machined (the mechanic suggested it to me instead of puttin same size pistons, he told me it would be better to machine it and get pistons bigger with more bore), do you think it's a good idea?. You say that if I install those Manley I'll get more compression. What will change in the car? will I have to change ECU or any other part (timing belt, valve, camshaft, or whatever) because of that compression difference?

with the piston and rod combination, all you will need to do is bore the block and check / grind the crank and bolt it together. the pistons and rods are full floating and are assembled without needing pressing together.

7.- If after opening the engine we see the rods are OK but the pistons are not, and I buy the Manley pistons only (with rings but without rods), you mean the Manley pistons will work with the original Mitsubishi rods, right?

As far as valves, i fitted manley stainless valves out of a datsun/nissan 200b they needed a little machine for the valve tip height, if i can find the part number, i will add it to another post

8.- I understand. I don't know what kind of machine will need since I don't know the valve tip height, but if you find the piece and you think the valves are good, I could try to translate it to spanish and explain it to my mechanic.

[John196701]

Aero

Manley pistons are better than standard
the 6 and 7 bolt are the number of bolts on the flywheel, the early 4g63 are 6 bolt, around evo4 they changed to 7 bolt.
there is no difference between the red tappet cover and black, in aus, the JA and JB models had a black rocker cover, the JD had red
yes, i would bore the engine, those manley pistons are available in std, 0.5mm and 1mm oversize, check your engine before you buy the pistons, just in case it is already oversize
the standard compression ratio on the starion engine is 7.6 to 1, those pistons may take it up to 8 to 1, you may have to retard to timing slightly, depending on the quality of your fuel
the manley pistons will work on the standard rods
i put the manley valves in my engine probably around 15 years ago, the collet height i think was correct, the overall length of the valve was longer, just had to shorten the height of the valve

[Aero-R]

You can't imagine how happy I am at this moment. Thanks man, it was nearly impossible to find OEM parts in this country without giving mitsubishi dealer a huge amount of money. Now I'm just shocked of finding better parts (even for competition) at a cheaper price. This is amazing.

I've seen that on that shop they sell even a crankshaft and headstuds, do you know if that one works like a charm in my Starion? (I ask in case I need it) or are they for other 4G63T not compatible with mine?

I've seen a timing belt too there (one from HKS and one from other manufacturer), but I don't know if that one is for DOHC. I'm afraid of buying something that won't work on my SOHC, just curious.

EDIT: By the way, there's a doubt from before I still don't have pretty clear... my engine is one single cam not twin cam, I don't know what "dish" means so I don't know if you mean they will work (excuse me, I know terms like bore and stroke, but I don't know what the word dish is on english, sorry!!). Fuel here I use is Shell 98OCT. If changing from stock to forged pistons, (as seems all the ones that are sold there are forged) the only change will be a timming adjust on the timming belt? or forged pistons may have problems with valves, head, and so? No way to get a pistons keeping stock compression ratio?

Huge thanks again for your understanding, this community is awesome.

[Mick]

hey mate keep up the good work!

DISH is sort of a slang/informal term for lower compression pistons and they have a literal dip in the middle to allow higher volume in the chamber.
Nearly all turbo motors run dish pistons because of the inherent need for low compression.
Im not sure about the valve clearance from the higher comp forgies on SOHC but maybe a thicker head gasket will be enough if there is an issue?
probably back to you john !

Best of luck with the build!
Look for quality brand parts on ebay from reputable stores you'll save yourself big $$$

[fugazi]

Hola Aero!

Don't you have any premium/super gas in/on Tenerife?
If you use 98 the slightley higher compression won't be any problem.
Any Manley, Ross, JE, CP forged pistons will be a good choise.
Look for "1Gen / 6bolt" on E-bay...
And you don't NEED to buy any connecting rods (7.-) if your not looking for a lot of horsepower... but the extra cost for a "piston and rod combo" is not that (much more) expensive!

Dish=> think of it like a "placa"... the piston-top looks a bit like a dish/placa, not totaly flat.

Greatings from the north! :beer

[Aero-R]

Hello everybody, thanks for the support, I'm loving this community a lot !

In Tenerife I use 98OCT fuel yeah, sorry (before I said 95OCT but I was in confusion, I use 95OCT for the Seat and 98OCT for the Starion).

I think I've understand the "dish" thing. After looking a bit on the internet and so on, seems that "dish" is like a perforation form in the top, and "dome" is an amount of material on the top. So know I understand that "dome" = more compression and "dish" = less compresion. The thing is that these seems to have less "dish" than the stock ones as John suggested, so now I understand why they'll give more compression ratio than stock ones.

The thing is: isn't better for turbos a lower compression if not the same stock one?, I've heard that a higher compression would mean more fuel consumption (so maybe I'll need to change injectors + fuel pump too?).

With higher compression ratio I don't know if my engine will blow, or if I'll have to mount other cams or other valve springs modifying all..

The thing is that it's nearly impossible to get parts here, so I'm trying to rebuild my engine with the best components without driving the engine into a unstable zone. I want the stability and reliability of the stock, and I don't care if I've to pay the amount of money of the Manley. What I care is that I'm afraid that difference in compression would mean negative things like the stated above in this post?

If there would be any pistons for my engine not necessary forged and with the same compression, is would be better? (I even don't know if I'll need forged ones, since it's only for road use).

In this page (http://realstreetperformance.com/store/ ... 0820766857) they have a list below with three of them highlighted in gray. Don't know if those 3 are the only ones they sell, of why those are highlighted then. At the right there's a chart for the compression ratio and if that's real.. my engine would change from 7.6:1 to 9:1? the ones above the highligthed are the same pistons but more dished to the CR goes to 8.5:1 instead 9:1?

I'm learning a lot with all of you, so I don't know if this ends on pages an pages of information because I'm learning lot of new documentation. Thanks !!

[John196701]

Aero

the amount of compression increase will be small, only a few points, more compression will not increase the fuel consumption at all, you might gain a bit of torque off boost, low compression was a thing of the past, most new turbo cars run higher compression than in the past, this is due to better control of the engine management. petrol today is better than in the 80's as well. the pistons rated at 8.5 to 1 have a piston dish -12cc and the 9 to 1 have a dish of -8cc
You could probably get cast aftermaket piston as well, they would probably be a few hundred cheaper. if you do forged and you want to change the computer later and run more boost, the engine will be able to handle it.
The timing belts you should be able to source from any aftermaket auto shop. the 4G63 sohc engine was quite common over hear, they where in the l300, starwagon. timing belt kits containing the adjusters as well would be around 100 to 150, the belt along would be around 50

[Aero-R]

Aero

the amount of compression increase will be small, only a few points, more compression will not increase the fuel consumption at all, you might gain a bit of torque off boost, low compression was a thing of the past, most new turbo cars run higher compression than in the past, this is due to better control of the engine management. petrol today is better than in the 80's as well. the pistons rated at 8.5 to 1 have a piston dish -12cc and the 9 to 1 have a dish of -8cc

Oh so both options from that chart are the same pistons but only with a difference on the dish. That 8.5 it says it the compression ratio max once mounted on the Eclipse, or that value will apply too and be the same if mounted in a Starion?

I understand your message, the thing is that I've fuel from now (98OCT) but a turbo from the past. I was a fraid that if I increase the compression ratio now, I won't be able to fit a better turbo in the future (a Garret at more kg/cm I mean).

You could probably get cast aftermaket piston as well, they would probably be a few hundred cheaper. if you do forged and you want to change the computer later and run more boost, the engine will be able to handle it.

I guess that by aftermarket you mean normal pistons not-forged (excuse my english)? if so, I really know that forged are better for later modifications, I was more afraid of the compression thing. If compression is not a problem, I trust on those manufacturers and will buy those forged.

The timing belts you should be able to source from any aftermaket auto shop. the 4G63 sohc engine was quite common over hear, they where in the l300, starwagon. timing belt kits containing the adjusters as well would be around 100 to 150, the belt along would be around 50

I've heard that even if the timming belt brokes, the Starion is not an engine that damages the valves with the pistons. Don't know if by chaninge the stock pistons with these new ones, that statement will change or not. The thing is that I've seen BOSCH timming belt kits for a similar price, but when I saw the HKS I was wondering if that one will be better and would fit a SOHC. If not, I'll end with the BOSCH one I guess (although seems that the BOSCH isn't as good as that other one that looks like for competition).

By the way, I bought a set of four NGK sparks exactly like the ones from stock, which are NGK BR7ES. I did this because that Mitsubishi old mechanic told me those work like a charm with the engine. With these pistons in mind and so on (the parts you suggested me) do you think those will work perfectly? (people asked me why I didn't buy new iridium NGK sparks and so on... but I just don't know if those end working as good as the old NGK BR7ES on the Starion).

[John196701]

Aero

yes, aftermarket, non-forged, bosch timing belts are OK, yes our engines are OK if the timing belt breaks, not that normally do, if you change them every 50 to 100k, i use NGK, won't use anything else, i would use B7ES, not the BR7ES, i use B9EGV in my car, but i am running 30psi boost

[Aero-R]

1.- So if I end with a higher compression, that won't mean I won't be able to fit a bigger turbo with more PSI in the future?

2.- Would you go with the 9:1 ones or with the 8.5:1 ones?

i would use B7ES, not the BR7ES, i use B9EGV in my car, but i am running 30psi boost

3.- Difference?, I tried to take a look at both data sheet but don't know your reason to prefer the B7ES, don't know if it'll make a huge difference.

[John196701]

Aero

8.5 to 1 pistons.

the R in the NGK plugs stands for resistor, it doesn't change the heat range at all.

you can still run a bigger turbo

[rodney007]

is your turbo ok?

[Aero-R]

is your turbo ok?

Yes it is mate, repaired 9000km ago.

I think this one will be a problem of rings only, and not necessary new pistons, but I won't know until we've it opened, so lets see =]

By the way, a friend of mine with a 4G63T SOHC widebody is looking for two parts: brake pump and starter engine (I don't know if those are the english terms but I hope that's understandable). I would like to buy both new if possible. Do you think those are parts I'll be able to buy new for him (like pistons and rods in this thread) or you suggest me to create a thread in this forum for 2nd hands units?