3B engine rebuild

[Vagsport]

Should be like brand new when completed, if not better. That is a wicked sig you got there Sweeper. My wife wasn't sure what to make of it :confused:

[S2central.net]

Jeffer - just a word of caution about machine shops for engine work. VERY VERY few have sufficient knowledge on the Audi 5 pot engines to correctly lighten and rebalance the crank. I'm no expert in this area but I know the subject is bit of a black art where 5-pot engines are concerned.

Have you checked these guys really have done this before and have happy customers ?

Sorry if this sounds a bit gloomy or you have done your homework already, but I've heard the odd horror story about crank rebalancing. That kind of damage cannot be undone !

I'm sure I also read that Volvo had to spend a long time with Audi engineers when thy designed the T5 engine to get the balancing right...


Paul

[Jeffer]

@ Sweeper
Thanks man received the CD! Will copy it and send it asap back to you.

@ Paul
Thanks for your comment. I've heard the same thing about the 5 cil. crancks. And spoke to some customers from this shop, they were all very happy (including one guy with a sport-quattro).
I've worked before with these guys, and they did a superb job. This was on a harley engine, somethimg totaly different
So I think it's also having a little trust in them.

But I really appreciate your comment, so if you got more things to warn me about, let me know.
Thanks man.

[Jeffer]

Got all the gaskets in, 7a camshaft arrived also. Cilinderhead, engine and cranck is done and looks the buisness. Al brand-new

Flywheel is lightend and balanced and clutch-contact surface redone.
Will post pictures soon
I can't wait to put it together :nana:

But there's one thing bothering me about the big-end bearings. I've ordered RS2 bearings and when I compared them with te S2 bearings (original) They had the same number :confused: And I am for sure I ordered RS2 bearings, no doubt about that. So I went to the engineshop to check it with him. He has a book full of bearing stuff. And he showed me that indeed all 20V turbo engines (and some other 5IL) have the same bearings :eek2: :confused:
Please explain to me. I hear everybody talking about rs2 big-end bearings............. Turns out there identical!

[Audi Parts Guru]

RS2 and S2 engine bearings are the same

[Jeffer]

WTF :wacked:

But, thanks for the clarification!

[porkkis]

Hmmh, I've somehow missed this conversation but here we go:

Sweeper: Dunno about Latvian Reinz distributor but perhaps asking some parts dealer helps.

Jeffer: Seems that you already had the crank done. Hope they knew what they were doing. The crank is externally balanced ie the flywheel is used to get the whole package in balance. Here in Finland is only one shop that can do it properly!
I had mine done as I currently build an engine to AAN block using the AAN crank and original 3B flywheel.

And about the bearings. I've understood that originally s2 and rs2 bearings were not the same but in some point the factory dropped the s2 bearings and now they only sell the rs2 ones.

I also had the head done. Exhaust valve guides got changed, valves and valve seats machined to fit and some exhaust side porting was done. Slight modification on the inlet valve sets gave a flow of 251hp as original head flows 234hp. The exhaust side is now around 15% more flowing at valve openings ~3-6mm, slightly less increase at larger openings.
I also put the head back together yesterday and put it on the block.

ps. the reinz set included the metal head gasket

[Jeffer]

Hi Porkkis,

Why do you think they did the cranck? Because of the bearings? They indicate that they are from '91

[porkkis]

I ment the balancing.

[Jeffer]

*UPDATE*

So I had to get new pistons! Treated myself on some nice JE pistons. Expect them over 2 or 3 weeks.

[desmo888]

Why did you have to get new pistons?
Any ideas on what my cylinders will look with 235k miles on the engine? Will it need to be bored?

Thanks,
Dave
'90 CQ
3B should be on the engine stand tonight.

[Pisobiker]

235k miles :eek2:

Well, if the car still runs fine, leave things the way they are, but if you need to rebuild the engine, I think pistons and rings won't be usable anymore.
1 oversize overboring will be required then.


Marco

[Jeffer]

The engine I'm rebuilding right now has done 200.000 km with his previous owner. The point wear it wears out is at the end of the stroke, where the piston takes the blast. When that occurs the piston rings expand and scrape themselves in the cilinder. So the only point where it was worn was at the top of the cilinder. Pistons were fine. So it had to be honed 2 oversizes to get that flaw out!

And remind that this was on a standard 220 HP 3B engine.

This can be credit to the person who drives it, it mainly occurs at high revs and a heavy right foot.

It was a possibility to NOT hone it. But then sooner or later the piston rings would be hanging in that hole they digged in the cilinder. With al the consecuences that follow

Greets,
Jeffer

[martinjs]

when i did my head overhaul a couple of months back had no bore wear at all and thats with 190k miles, now its upto 300 ish bhp and will be 330 soon. dont expect any problems.

[Jeffer]

Maybe I was just unlucky, You never know, there just so much factors that can couse those things.