Audi TT Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
352 Posts
Discussion Starter · #1 ·
I bought some Maxspeedingrods forged rods a couple of months ago and finally started the job today. Cylinder head off, dropped the sump, pulled out the pistons.
To prepare for this I studied old forum posts and watched Youtube videos. I've never attempted anything like this before.
Tomorrow I'm going to gap the new Mahle piston rings. I have a Bentley manual but I don't see anywhere in the manual about piston ring gap specs.
I found this old ttforum post though.
But that is for standard stock horsepower, should the gaps change for higher horsepower?

Next on my list... figure out how to measure bearing clearances with my Plastigauge. I have new Glyco bearings.
Also I got a Flex-Hone 3 1/4" 180 grit cylinder honer.

Any advice is appreciated!!

Vehicle Motor vehicle Car Blue Automotive tire
Musical instrument Wood Auto part Statue Font
Hand Liquid Fluid Automotive tire Hat
Crankset Tool Wrench Hand tool Gas
 

·
Registered
Joined
·
307 Posts
Some pictures here from my APX rebuild thread Engine rebuild and trackday project log

The TT Bently manual is odd as it seems to skip engine assembly chapters.

I used the ring clearances from here Audi Workshop Manuals > A3 Mk1 > Power unit > 4-cylinder 1.8 ltr. 5-valve turbocharged engine (154-165 kW), mechanics > Enginecrankshaft group, pistons > Dismantling and assembling pistons and conrods > Pistons and conrods - exploded view and I think nearly all the 1.8t's are the same?

My understanding is different ring gaps based on increased horsepower is only for aftermarket pistons with different thermal expansion properties but I could be wrong.
 

·
Registered
Joined
·
9,965 Posts
I assume your engine is still in situ? What are you going to do if the clearenesses with the plastiguage are out? Remove engine remove crank etc ? I didn't measure mine as x wouldn't have done that other thing.

Any reason you didn't get rifle drilled rods to lubricate the small ends?

I made my gaps slightly bigger for more horse-power and if idling in traffic for long periods it dumps some smoke. I assume you have ring compressor? make sure you use a pistons to push the ring down when measuring the gap.

Make sure you follow the ARP2000 instructions when stretching the rod bolts, and be careful lowering the piston down into block to make sure you don't hit the oil squirters.

What head work have you done? Supertech Inconel exhaust valves?
 

·
Registered
Joined
·
352 Posts
Discussion Starter · #4 ·
I assume your engine is still in situ? Yep engine still in the car. I don't have the ability to remove the engine. I'm doing this outside on my driveway.

What are you going to do if the clearensses with the plastiguage are out? Remove engine remove crank etc ? I don't know, probably come on here and ask what I should do next. The car was totally stock for about 18 years. 2001 with 152k gentle miles on it. I only just got my first tune last year, I think the engine is in good condition. Since the tune I became addicted to modding.

Any reason you didn't get rifle drilled rods to lubricate the small ends? I read that it's not totally necessary, and my plan for the car has been to keep it low budget.

I have a ring compressor and piston ring pliers. Never used either before. Tonight I'm going to clean the pistons and maybe fit the new rods on the pistons.

I decided that the cylinder head is out of my league and I'm taking it to a cylinder head shop tomorrow to have it inspected/rebuilt. I need advice on exhaust valves. If I should get inconel exhaust valves then I will. I'm going with an E85 tune and the exhaust is supposedly cooler so do I need them?
Not sure what my horsepower is going to be. My mods are: CAI, Badger5 TIP, new bigger K04-23 turbo, tubular exhaust manifold, 3" downpipe, cat-less, Wagner FMIC, Magnaflow back-box, 550cc injectors, DW65v fuel pump. And I did all of it by myself learning while I'm doing it!

Thanks for the link darylw357 I do remember reading some of it here and there over the past year.
 

·
Registered
Joined
·
9,965 Posts
What tubular manifold have you got, they usually crack, I have a Chinafold and ported it for a stock k04 hotside and recently re-ported for an AET hybrid k04 VT262-C as it has a wider hotside.

I know the stock exhaust valves are sodium filled and very expensive, don't know enough about e85 to advise.

Also careful cleaning the small ends, decided to leave them with the pistons in cola overnight and it stripped off the chrome.
 

·
Registered
Joined
·
352 Posts
Discussion Starter · #7 ·
Tonight I de-glazed the cylinders with my Flex-Hone 3 1/4" 180 grit silicon carbide tool, P/N GB31418. I read somewhere on the internet to coat the tool and cylinders with automatic transmission fluid so that's what I did. Only did about 15-20 seconds per cylinder, with the drill in forward then reverse to get a crosshatch pattern. I put a wet rag at the bottom of the cylinder to prevent the sludge from getting on the crankshaft. Turned out good I think.

Then spent a couple hours cleaning my old pistons. I used half acetone and half automatic transmission fluid and a steel brush, and a pick to scrape out the carbon deposits in the piston ring grooves. Then after all that I wondered if I should upgrade the pistons but after searching the internet, looks like "high performance" pistons start at about $600, out of my price range.

Then I measured the piston ring gaps of my new Mahle rings in the cylinders. I measured near the top and bottom of the cylinders and all of the compression rings were within spec (0.2-0.4mm). Two oil rings were too tight so I sanded them a tiny bit.

StuartDB the exhaust manifold is a Relentless V4, or a clone of it. Found it on eBay very cheap. We'll see if it cracks! I got it as an experiment along with replacing my turbo.

Automotive tire Pneumatic tool Gas Machine Drill
Motor vehicle Automotive tire Automotive exterior Rim Bicycle part
 

·
Registered
Joined
·
9,965 Posts
Yeah, I think it'll crack.. they are a real pain to get 1 of the bolts tightened, some people use studs but then a pain to remove the turbo in the future. Mine also fouled with the heat shield on the back of the head. A stock manifold will make 300bhp if it is slightly ported.
 
1 - 8 of 8 Posts
Top