TomPengelly

Im building a 1.8 silvertop zetec turbo on a budget. Im using 1.8 20v turbo audi tt pistons, forged rods with modified small ends for pistons, rover turbo inlet, focus rs exhaust manifold and turbo.

I was going to use devil developments turbo valve springs, and a 2.0 exhaust cam and a 1.8 inlet cam. Do i need to do anything else to the head to achieve my target of 300bhp?

Port/polish, 3 angle valve seats ect? Or for the cost would it not be worth the power improvement?

Anything else i should consider engine-wise? I have all the parts, engine is coming out next weekend...

studabear

What head gasket are you using? Might need head and block skimming/decking.

Arp rod bolts?

TomPengelly

I have ARP rod bolts, they arrived yesterday!

Unsure on headgasket- was going to ask advise on that too. Any suggestions?

Johnny Knoxville

ST170 head gasket

I would say no head work would be needed for 300bhp

TomPengelly

Can i use the st170 gasket on a 1.8?

studabear

What size are the bores on a 1.8 silvertop? You might be able to use a 1800cc blacktop zetec mls gasket but you would have to find out how thick they are and calculate what compression ratio your gonna have with your piston choice.

Johnny Knoxville

Ok sorry 1.8 as said above black top one then

TomPengelly

Cheers for the replies. I would be stuck without you lot.

So use a 1.8 blacktop mls gasket- on my 1.8 silvertop?

So this one would be fine?

http://pages.ebay.com/link/?nav=item.view&alt=web&id=251683256400

TomPengelly

Or would item number 231277569120 be better?

Johnny Knoxville

Expensive but you can get them from Ford cheaper

TomPengelly

Ok cheers. So just a multi layer steel gasket- for a 1.8 blacktop focus, or can i just get an mls one for the silvertop- are they different?

Johnny Knoxville

Silver top gaskets arn't MLS

studabear

Are silvertop and blacktop 1800cc engines the same bore size?

Johnny Knoxville

yes there are

Churtz

The multilayer steel gasket will give you a CR of 11:1 on 1.8 silver top with audi pistons. You need the chunky monkey head gasket.

Smidydevil

Really? Iv been told these Pistons and headgasket are about8.8:1 , didn't measure mine and calculate it when I built the engine to be fair 😕

Johnny Knoxville

There are two tyres of 1.8t Pistons, Audi TT's and A3's engine code AGU

TomPengelly

I do have AGU pistons from an A3

TomPengelly

Would the normal mls gasket be no good then? What thicker ones are any good to use? I was going to order the one i need tonight

Smidydevil

I thought it was just the Gudgeon pins that are different on the audi Pistons? 19 or 20mm.. I have the 20mmm ones fitted to my engine getting me worried about the CR now.. I'm using this set up aswell forged rods audi Pistons DD valve springs and a blacktop head gasket along with many other parts

Smidydevil

Also as there was a little confusion higher in the thread I fid need my block boring out but was minuscule probably do it with a honing tool to be honest, and to run a MLS gasket I had the block and the head decked to ensure there dead flat n true for a good seal

TomPengelly

Cheers for the replies. I shall also get my block and head skimmed. Maybe i should just ask my supplier for the thickest head gasket for a 1.8 zetec?

Churtz

My mate has done it....A couple of times now. He's posted on fiesta turbo forum about it I think. Definitely have to run the thicker hg to get the cr down.

TomPengelly

Cheers!

Also, people say to use a 1.8 inlet cam and a 2.0 exhaust cam. I already have 2.0 cams, and my original 105bhp 1.8 cams. Can i use the 105 inlet cam or do i need a 1.8 130bhp inlet cam?

TomPengelly

Ive just called my supplier to order a set of 1.8 20v pistons. They asked what piston ring size i need??

Turbo Zetec

iTrader: (1)

Not true, the pistons sit 0.5mm lower down the bore than standard ones and have a dish in them too. Compression works out to roughly 9:1 with a 2.0 head, which should be fine for reasonable power as long as you have the management to cope.

Churtz

Just talking from experience. Was a 1.8 head though I think.... done it 2 times now with a friend of mine.

TomPengelly

Is it better to use a 2.0 head or stay with the 1.8? Are there any other differences?

TomPengelly

Right, i need to order my head gasket lol- but still dont know if i should go for a 1.8 mls gasket or just the thickest one my supplier stocks?

I was going to keep my 1.8 head.