Do I have a 1.8 head?

[Nuzzi]

I pulled off my valve cover today for inspection and happened to notice the head is cast with "1.8" on the left hand side, also with a "4" directly under the 1.8

Its a 91 talon tsi manual, can someone tell me whats going on here? I received little info on the car when I bought it, and I keep finding weird things that have been done.

 

[90tsiawdturbo]

1.8s are sohc

 

[Nuzzi]

It's definitely a dohc turbo.

 

[CrackedDSM]

It could be a G4CN head. Certain Hyundai 1.6 and 1.8l heads bolt right onto our blocks, and they have a smaller combustion chamber(43cc Hyundai head, 47cc DSM Head) that gives a decent bump in compression. Take some pictures and throw it up. Hopefully BogusSVO chimes in when you post up pictures, because if anyone will know it'll be him.

 

[Nuzzi]

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[BogusSVO]

Yep, that would be the 1.8 Hyundai head.

Looks just like a 1g 6 bolt head for a DSM, but has a smaller combustion chamber.

Pull a spark plug and see if you can see the number on the piston.

If you have the 63DT stock 6 bolt pistons, then enjoy the bump in your CR

 

[lasershark]

roughly how much do you think it would bump the compression ratio?? Purely for knowledge sake, just curious

 

[Nuzzi]

From what I've found looks like about half a point. Can I use dsm cams in this?

 

[BogusSVO]

I am not going to hazard a guess at how much it will bump the CR. too many other things can come into play.

Yes the DSM cam should bolt right in.

 

[Nuzzi]

Cool, I saw somewhere that the Hyundai cams were smaller diameter...I'll see if I can look at the pistons tomorrow. Thanks.

 

[90tsiawdturbo]

Learn something new everyday! BogusSVO, you're the best

 

[Nuzzi]

Just checked the block, 4g63 stamped on the front and I can see 63dt stamped on the pistons. I also noticed the turbo is being oiled from the head, shouldn't it be tapped into the ofh?

Just pulled the maf and intake hose out, turns out the turbo is undersized. The inlet is smaller then the stock rubber intake hose, they had the hose clamp overtightened to the point it pulled in the rubber on itself. One thing after another, and the maf looks pretty beat too.

 

[BogusSVO]

Most factory 1g turbos are oiled from the head.

So you have a 4g63 6bolt with a 1.8 head.

 

[Nuzzi]

thanks for the replies, hopefully soon ill get this thing on the rd.