2G Advice for my 6 bolt rebuild

[Galipso]

Hey Everyone,
I tore apart my engine after sitting for 7 years. Found minor scratches in the cylinder walls, pistons, bearings and crank. SO, i guess i'm ordering all new internals. The block was already bored to 85.5mm, so it looks like i need to get it bored out to 86mm now. I'm currently looking for a machine shop in the Florida area so if anyone has recommendations i'm open to it.
My horsepower goals are 350-400 range. I already have my 2G head fully rebuilt with BC 272 Cams and all new internals from Clearwater Cylinder Heads. They did a great job, highly recommended.

Since im replacing my crank, i was thinking of doing the 2.2L stroker kit. This means getting a 94mm Eagle Crankshaft.
I found this one in ExtremePSI:
https://www.extremepsi.com/store/Ea...aft-94mm-Mitsubishi-Eclipse-90-92-6-Bolt.html

With this crank, i want to keep my Eagle Forged 150mm Rods. I inspected them and there doesn't seem to be any damage. Save some $ there.

That means with a 94mm crank and 150mm rods, i should get a Stroker Piston at a 86mm diameter. This is where i get a bit confused.
I found these pistons on ExtremePSI:

EXTREME PSI : Your #1 Source for In Stock Performance Parts

Specs:

Stroke: 94mm
Rod Length: 150mm
Compression Ratio: 9.0:1
Wrist Pin: 21mm
Ring Thickness: 1.0mm x 1.2mm x 2.8mm (85.0mm), 1.0mm x 1.2mm x 2.8mm (85.50mm), 1.0mm x 1.2mm x 2.8mm (86.0mm)
Bore SIze Available: 85.0mm (Standard), 85.5mm (+0.5mm), 86.0mm (1.0mm)
QUESTIONS
Q1: These CP Pistons would pair with the 150mm Eagle Rods and 94mm Eagle Crank, right?
Q2: I see Main and Rod bearing for 'Standard', and 'Standard with Additional Oil Clearance .001"', do i need the added oil clearance?
Q3: With my head decked, my block being decked and my HP goals, what kind of head gasket should i get? I'm leaning to a Cometic MLS 1.6mm.
Q4: Any other advice/suggestions is really helpful.

I've been reading Tech Articles, i just want to be 100% before i order a couple grand worth of parts and get advice from the community.

Stroker, Destroker, and Long Rod Engine Basics

Strokers, Destrokers, and Long Rod Engine Basics The details behind various 4g6X engine builds. The point of this article is to provide a better understanding of the various 4g6X based engines. To keep this short and sweet, I'll simply cover the specs of each build, the general Pros/Cons, and...

www.dsmtuners.com

 

[miliman13]

Yeah I always hear good things about Clearwater cylinder heads.

Depends were you are in FL I may be able to make recommendations

Here is my advice, don’t order a single thing until you have fully disassembled the entire engine and done a measurement of every rotating surface with micrometers.

This way you will have many of the answers you seek and larger pistons are not always the solution I had a cylinder repaired with a steel sleeve so I wouldn’t have to change my setup.

Much more affordable over boring the entire block
Reference :

Street Build - Red5.

It's very difficult to lap with the suction cup, so I had to use the drill and hose followed by the suction cup.Also laped with a towel covered in ether to do a final clean up. The valves are like silent ninjas stalking in the shadows on a cold and windy night. Lol. They are quite and smooth...

www.dsmtuners.com

 

[Galipso]

Here is my advice, don’t order a single thing until you have fully disassembled the entire engine and done a measurement of every rotating surface with micrometers.

This way you will have many of the answers you seek and larger pistons are not always the solution I had a cylinder repaired with a steel sleeve so I wouldn’t have to change my setup.

Much more affordable over boring the entire block
Reference :

Street Build - Red5.

It's very difficult to lap with the suction cup, so I had to use the drill and hose followed by the suction cup.Also laped with a towel covered in ether to do a final clean up. The valves are like silent ninjas stalking in the shadows on a cold and windy night. Lol. They are quite and smooth...

www.dsmtuners.com

All 4 cylinders and all the bearings were bad, hence why im going forth with just boring out the cylinders to 86mm. I'll see if i can upload images later. Other than that, what other measurements do i need to get verification of? Won't most machine shops be taking the appropriate measurements in order to have proper fitment?

Good advice on the block cleaning there in your post, but i intend for the machine shop to install the crank, rods, pistons before they hand it back over to me. I have better faith that they can get the correct specs and tolerances if I provide them the details. Right?

 

[miliman13]

All 4 cylinders and all the bearings were bad, hence why im going forth with just boring out the cylinders to 86mm. I'll see if i can upload images later. Other than that, what other measurements do i need to get verification of? Won't most machine shops be taking the appropriate measurements in order to have proper fitment?

Good advice on the block cleaning there in your post, but i intend for the machine shop to install the crank, rods, pistons before they hand it back over to me. I have better faith that they can get the correct specs and tolerances if I provide them the details. Right?

I remember when I used to have faith too.
That was back when all 3 of my previous engines failed , most times soon after a return from machine shop.

Yes it makes sense they would do everything, but that is not my experience, hence what you saw in my cleaning post.

Don’t set yourself up for future disappointment, I only speak from experience.

Most machine shops prefer when the customer provides them with a set of instructions, their work results are exact when you design your own clearances for your intended applications and uses.

This is why bearings come in different sizes and rings get trimmed.

Do use them to at least determine what your new dimensions are after resurfacing every surface and then from there you have a base line to know what’s specs you need based on their recommendations.

 

[Galipso]

Most machine shops prefer when the customer provides them with a set of instructions, their work results are exact when you design your own clearances for your intended applications and uses.

This is why bearings come in different sizes and rings get trimmed.

Do use them to at least determine what your new dimensions are after resurfacing every surface and then from there you have a base line to know what’s specs you need based on their recommendations.

So to start out, i should just give them the bare block and have them clean, inspect and measure? I thought they usually needed the girdle, studs and pistons with the block so when boring and honing they can match the piston into the cylinder...?

Also, I've never done an engine build, so I'm definitely worried I wouldn't put everything together correctly and actually do a worse job of it.

 

[DSMPT]

Q1: These CP Pistons would pair with the 150mm Eagle Rods and 94mm Eagle Crank, right?

Yes. But before ordering, you should make sure if your eagle rods have 21mm small end. Eagle have 6 bolt rods with 22mm small end, too.

Q2: I see Main and Rod bearing for 'Standard', and 'Standard with Additional Oil Clearance .001"', do i need the added oil clearance?

For your power goal, usually you don't need it. This should also be determined by the oil viscosity you would use. You should ask your engine builder for his plan unless you build it by yourself.

Q3: With my head decked, my block being decked and my HP goals, what kind of head gasket should i get? I'm leaning to a Cometic MLS 1.6mm.

It would work for sure. But you would need extra attention to use a MLS, so maybe a Mitsubishi or Felpro composite head gasket would be easier. I am sure many people would recommend it.

As for the thickness of 1.6mm you selected, I assume you selected a thicker one because the valve timing, the piston to valve clearance and compression difference due to the cylinder head and the block are resurfaced. Usually the standard cometic or many aftermarket standard MLS is about 1.3mm and this is already slightly thicker than the factory one and you still have suficient piston to valve clearance, so usually extra thickness is not exactly necessary unless you have a specific reason such as adjusting the compression ratio. If you would go with the 1.6mm one, that would probably drop the CR by approxi 0.2 from the advertised number.
If you care about a little valve timing difference, you would need to degree cams.

 

[jed344]

Like said be sure your rods are 21mm pin. I have back in the day built 6 bolts with rods that used the 22mm pin and 7 bolt piston.

The extra oil clearance ask your builder or if you are building it then it is trial and error. I generally try to set the rods a hair looser then mains on oil clearance. Most rod manufactures want at least .002 oil clearance. I always have both sets on hand. Brand new cranks sometimes are "fat" on the journals and require non standard bearing's or a combo of standard and non to get oil clearance as i want. Most used cranks that have been polished end up where i like with just standard.
The builder will have what he likes to target. I like to see .0017-.002 on the main and .002-.0023 on the rods. This can change based off the build, parts and goals. These clearances i use 20w50 on as they are on the larger side.

The head gasket question depends, if you want to us a MLS then the block and head need to be at least 50 RA surface. Then i check piston protrusion and also check how much has been decked from the head and CC of the chambers.
This then i use to decide the thickness of the gasket i want to use to achieve the theoretical " quench area".
Honestly quite a lot has to be decked from the head or the block to require a 1.6mm thick gasket. I think only once i needed it and that motor was .002 piston out of the hole and head was at or beyond service limit.
99% of the time a factory thickness or 1.3mm is just fine. Bigger deal is to be sure the surface finish is correct otherwise you will battle the head gasket.
We have ran the regular composite gaskets oem or felpro to well into the 30 psi range depending on studs. Standard arp and these gaskets 33-35psi all day. L19's close to 40 psi.
MLS we love the HKS mls. We have used this gasket with L19's well into the 40psi range. But if you do not have the surface for it the mls will leak before a composite will.

 

[Galipso]

Yes. But before ordering, you should make sure if your eagle rods have 21mm small end. Eagle have 6 bolt rods with 22mm small end, too.


For your power goal, usually you don't need it. This should also be determined by the oil viscosity you would use. You should ask your engine builder for his plan unless you build it by yourself.


It would work for sure. But you would need extra attention to use a MLS, so maybe a Mitsubishi or Felpro composite head gasket would be easier. I am sure many people would recommend it.

I didn't know about the 21/22mm pins. I'll check for sure.

I'm on the fence about having an engine builder assemble the engine based on what @miliman13 said.

The builder will have what he likes to target. I like to see .0017-.002 on the main and .002-.0023 on the rods. This can change based off the build, parts and goals. These clearances i use 20w50 on as they are on the larger side.

I'll have to consult the machinist starting with standard bearings it sounds like.

The head gasket question depends, if you want to us a MLS then the block and head need to be at least 50 RA surface. Then i check piston protrusion and also check how much has been decked from the head and CC of the chambers.
This then i use to decide the thickness of the gasket i want to use to achieve the theoretical " quench area".
Honestly quite a lot has to be decked from the head or the block to require a 1.6mm thick gasket. I think only once i needed it and that motor was .002 piston out of the hole and head was at or beyond service limit.
99% of the time a factory thickness or 1.3mm is just fine. Bigger deal is to be sure the surface finish is correct otherwise you will battle the head gasket.
We have ran the regular composite gaskets oem or felpro to well into the 30 psi range depending on studs. Standard arp and these gaskets 33-35psi all day. L19's close to 40 psi.
MLS we love the HKS mls. We have used this gasket with L19's well into the 40psi range. But if you do not have the surface for it the mls will leak before a composite will.

So what's the advantage of having an MLS gasket? I for sure thought i needed a thicker gasket from the surfaces being decked but it sounds like that may not be the case. I'm looking for a long lasting engine more than i am pushing horsepower limits. Therefore, it seems a composite gasket is better suited here.

 

[jed344]

I didn't know about the 21/22mm pins. I'll check for sure.

I'm on the fence about having an engine builder assemble the engine based on what @miliman13 said.


I'll have to consult the machinist starting with standard bearings it sounds like.

So what's the advantage of having an MLS gasket? I for sure thought i needed a thicker gasket from the surfaces being decked but it sounds like that may not be the case. I'm looking for a long lasting engine more than i am pushing horsepower limits. Therefore, it seems a composite gasket is better suited here.

Like i said quite a lot has to me machined off to require a thicker gasket. The composite gasket is enough for most people. The MLS when correct surface finish, good gasket, and good studs then removes the head gasket as a weak point. Cylinder pressure's just get so high that it is not able to handle it.

I currently am using a OEM composite gasket. I have O rings cut into my cylinder head and L19 studs. This set up i have found to work similar to a MLS and L19's in what it can hold.
When i recommend a MLS and say l19 studs or a similar set up to mine. These car's require the head gasket to not be a fusible spot per say.
They all are running well north of 40 psi on 62+mm turbo's and trap 140+ mph. The average dsm does not need to spend the extra money and add the risk that if machine work was not up to par that it leaks. When a MLS is used with surfaces not to required spec they can push coolant at VERY low boost levels. Well before the composite would in this case.