Overhauling an engine.. few questions..

[naughtika]

hey fellas, I've been contemplating on getting my spare engine overhauled.. and today I've decided Im gonna save up and do it.. so that it feels like a brand new engine again

few questions though, since I dont know much about overhauling an engine.. so this question goes to people who've done it like Jonson, Jungle and others who lurk in this community

my questions are..

1. if I was to go forged internals - is it wise to use oem bearings? like the ones between the crank shaft and conrods?
2. head gasket - what are my options for it? I know RPW do sell them, so that's another option.. but which one would you use - oem or aftermarket?
3. porting - yup, gonna get this done, specially on the exhaust side..
4. valves & valve springs - are there any known aftermarket springs available for our cars?
5. cams - I will stick with the oem one since I dont use much anything above 4500rpm
6. adjustable cam gears - still contemplating on this.. but since I'll have 2 sets of cam gears I can just send it to a workshop and get them done..
7. transmission - I'll do this next time.. main goal is to get the engine done..

I'll do it once and do it right..

I'll add more when I think of other things..

 

[Fully]

1. if I was to go forged internals - is it wise to use oem bearings? like the ones between the crank shaft and conrods?
You could use a thinner (racing) journal bearing for more oil.

2. head gasket - what are my options for it? I know RPW do sell them, so that's another option.. but which one would you use - oem or aftermarket?
Go for a steal one

3. porting - yup, gonna get this done, specially on the exhaust side..
thumbs up!

4. valves & valve springs - are there any known aftermarket springs available for our cars?
Stock seem to work well

5. cams - I will stick with the oem one since I dont use much anything above 4500rpm
You could move the power curve more to the left.

6. adjustable cam gears - still contemplating on this.. but since I'll have 2 sets of cam gears I can just send it to a workshop and get them done..

7. transmission - I'll do this next time.. main goal is to get the engine done..

Injectors?

 

[naughtika]

injectors.. will be done prior to the overhaul.. same goes to the fuel pump, pressure regulator, and intake pipes as well..

this thread will only be concentrated on the engine itself..

 

[Fully]

Injectors before hand?
You will have to take them out to rebuild your engine.

What sort of power are you chasing?
If you are after stock its going to be a waste of time going for forged internals.
You need to have a goal before you start =)

 

[naughtika]

Injectors before hand?
You will have to take them out to rebuild your engine.

What sort of power are you chasing?
If you are after stock its going to be a waste of time going for forged internals.
You need to have a goal before you start =)

im after between 300kw and 350kw..

also I will buy the fuel pump, regulator and injectors before completion and will most likely sit on the shelf for ab out 12 months..

 

[Jonson]

You really need to decide what you want from the car and work backwards from there. 350kw atw in a Legnum is gonna be hard to get due to lack of space and the turbos required to get you to that goal. Also remember with 350kw you will need a massive fuel system, brake upgrade, driveline upgrades and more than likely management upgrades. The build cost will go through the roof.

Knowing that you want 350kw I would say deifnitely forged internals, definitely MLS head gaskets, enhanced (ARP or the like) fasteners throughout the engine, very solid bottom end and heads (crack tested everything, heads softness checked etc), the turbos you'll need to make the power will be decent sized, which means definite yes to cams (to make the power band useable), gears, springs, retainers, oversized valves. I would hazard a guess with labour in the vacinity of 15k-17.

If you don't go much above 4500rpm it will be near impossible to not only make that power but to find turbos that can puff that much at low RPM. It really comes down to how much money you have and what you want from the car. Figure that out and then you can start getting serious about it.

 

[unclepaulie]

chris, if you want to crack 350, i reckon you'd need some mild cams, like 264's. Combined with some larger exhaust valves like simon said.

 

[Dr_Josh001]

chris, if you want to crack 350, i reckon you'd need some mild cams, like 264's. Combined with some larger exhaust valves like simon said.

Disagree. A good port on the exhaust and tuned length manifolds (which I have designed, just need to get them out of the computer!) and GT2876r turbos would crack 350 easily. The longer duration cams and larger valves will increase flow but this is what one might do if they're trying to crack 350kw with a 4cylinder. That's only my 2 bobs worth though.

P.S. Just thought I'd add that with the build Macca and I are doing we'll be only upgrading to forged pistons & rods and larger valves. The rest including the springs and cams and crank to remain stock with a good amount of porting to the exhausts. I've been told by a couple of local engine builders that if valve springs are too stiff the stock hydraulic lifters don't work properly and should be upgraded... more $$$!

 

[naughtika]

Disagree. A good port on the exhaust and tuned length manifolds would crack 350 easily. The longer duration cams and larger valves will increase flow but this is what one might do if they're trying to crack 350kw with a 4cylinder. That's only my 2 bobs worth though.

my exact same thought.. I know Bennoz gained an extra 10% when he added vernier cam gears and thats only on the exhaust side..

so what more can you do with a pair of TD04-19T.. a 3000GT with a pair of them can crack easy 650hp at the wheels.. I'm only asking for around 450hp..

and I do use the higher rev range just not all the time.. I dont live my live 10 secs at a tiime.. LOL.. but you know what I mean

 

[naughtika]

Josh, how are you upgrading the valves? any particular brand and part numbers?!

 

[Dr_Josh001]

Josh, how are you upgrading the valves? any particular brand and part numbers?!

Not 100% sure, I will need to check the length but possibly oversize 4g63 stainless valves from the US might fit. After all the 4g head is near identical just with 1 more valve train. I will just need to get the heads machined so they seat properly. Once again lack of time and personal stuff happening has got in the way of finding out little bits of info like that.

 

[naughtika]

I wont know what size we should have for the valves as I haven't pulled the engine apart..

my dad is a little hesitant about it since the engine's only done 80k kms..

I asked him if he prefers to overhaul the 200k kms engine.. he just doesn't see my point in spending $$$ on the engine..

this is when practicality vs want collides..

I'll just slowly start buying the parts next month and surprise him with it..

 

[jet150]

My opinion is first you have to decide what you want from the engine then build accordingly. You don't need forged pistons and rods unless your thinking of setting your boost at 20psi and over. Take my car for example stock internals 18psi 287awkw and over 100 dyno runs.

If your gona use the TD04,s gut them completly, machine the housing and fit bigger and better cores. Also what are you gone do with your fuel system? and Ecu?

 

[naughtika]

My opinion is first you have to decide what you want from the engine then build accordingly. You don't need forged pistons and rods unless your thinking of setting your boost at 20psi and over. Take my car for example stock internals 18psi 287awkw and over 100 dyno runs.

If your gona use the TD04,s gut them completly, machine the housing and fit bigger and better cores. Also what are you gone do with your fuel system? and Ecu?

That's one way to look at it..

In my opinion, dyno runs shouldn't be compared to real life situation, as with dyno's they are in a controlled environment..

Also I have set my mind on what I want it to do, i want it to put out 350kw max.. but doesnt mean i want my engine's limit to be at that.. So i want the engine capable of handling 600kw..

Twin TD04-19T's should be able to do the job, I think it'll do the job at around 24-26psi.. and why gut them if they're brand new?

Fuel pump would be in tank still.. Walbro?!?

Ecu.. Will be using what I have right now.. Why replace it if its just as capable..

 

[Nitephyre]

I lkie where this is going

 

[fieldy107]

Kristian the point Rob was making with the 100 dyno runs is that if the internals can hold up to 100 dyno runs (dyno runs are torture for cars really) and not fall to peices, they should be able to put up with anything thrown at them on the road

 

[naughtika]

Kristian the point Rob was making with the 100 dyno runs is that if the internals can hold up to 100 dyno runs (dyno runs are torture for cars really) and not fall to peices, they should be able to put up with anything thrown at them on the road

I got his point, no pun intended.. but imo, 100 dyno runs doesn't really equate to your everyday driving, due to change of situation and climate.. specially here in oz where one day its cold and the next hot..

with the dyno, the operator pushes the car at his convenience, so I don't see that as a torture, just a means of testing what the engine can provide at a simulated situations, usually at a room temperature right?

 

[fieldy107]

Dyno conditions are usually harsher then most road conditions, for a few reasons. Dyno runs are done at full throttle, the rate I drive it would take me at least a year (probably more) to do 100 full throttle sprints in 3rd or 4th gear (whatever they use). Room temp in a workshop is usually just as hot as outside, if not hotter, so being indoors makes it no easier on the car. The last reason is that the fans they use will never push the air around your engine bay like travelling at speed will. So in my opinion 100 dyno runs = several years of road driving.

Not that Robs results are valid to you anyway, he is making 287kw and you are chasing 350kw. So who knows if stock internals would hold up to that, no one has tried. If I was chasing 350kw I would want forged internals, just for peace of mind

 

[naughtika]

Dyno conditions are usually harsher then most road conditions, for a few reasons. Dyno runs are done at full throttle, the rate I drive it would take me at least a year (probably more) to do 100 full throttle sprints in 3rd or 4th gear (whatever they use). Room temp in a workshop is usually just as hot as outside, if not hotter, so being indoors makes it no easier on the car. The last reason is that the fans they use will never push the air around your engine bay like travelling at speed will. So in my opinion 100 dyno runs = several years of road driving.

Not that Robs results are valid to you anyway, he is making 287kw and you are chasing 350kw. So who knows if stock internals would hold up to that, no one has tried. If I was chasing 350kw I would want forged internals, just for peace of mind

point taken.. about 100 dyno runs vs real driving situations..

also same approach as me, rather be safe than be sorry..

 

[naughtika]

does anyone know if someone out there is using a set of Pauter Forged Rods? I'd like to know what their opinions are..