2.5 V6 Rebuild Thread - Alfa Romeo Forum
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(Post Link) post #1 of 12 Old 09-04-13 Thread Starter
Status: The V6 lives! Phew.
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2.5 V6 Rebuild Thread

So after much stripping and cleaning, I'm finally at the point of rebuilding my V6.

The engine has come out of a 2nd car that i bought to keep my other 156 on the road. I was going to move the car on once I had raided the parts I needed from it but then realised that with the engine having only done 40 odd thousand miles i should do something with it.

This happened at roughly the same time my aux belt made a break for freedom and shredded itself. This causing the car to overheat and once tested came back as HGF.

So that was about 8 months ago, she still runs fine but that engine will be coming out to make way(hopefully!) for this rebuilt engine. I sorted out a garage and got to work stripping the engine out and cleaning everything up.

Fortunately, I work for a big engineering company and have access to pretty much everything I needed to strip and clean the engine.

So I'm now at the point of putting it back together I thought I'd start this thread for anyone that's interested. Any tips and advice will be greatly appreciated.

First thing I've done is measure up my crankshaft. Figures I've got are:

59.96 across all 4 diameters and

51.98 across all 6 diameters.

Will I need to purchase standard shells for these sizes?

I'll update as much as I can, but for now a few pics.
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Ah, those were the days: engine bits on the kitchen table.

Will follow this thread as I'll want to do similar to a 2.5 V6 to go into my kit car. That's when I've actually go hold of one that is!
 
(Post Link) post #3 of 12 Old 10-04-13 Thread Starter
Status: The V6 lives! Phew.
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Ha! The engine parts seem to have taken over my flat. Once I get all the parts up to the garage I'll get some more detailed pictures of them.

Just in the process of spraying up various parts, block, heads and anything else that needs a lick of aluminium paint.

This will be a straight forward rebuild with only minor mods if I can afford them. Q2 and a GTA clutch are on the list so far. The engine was in good health before the strip and I've checked everything that I can think of, flatness of the heads, condition of the crank etc, so all that I will be replacing are things like gaskets, bearings, shells etc.

On the negative side I found that the gearbox had some chipped teeth and the casting for the top starter motor bolt had broken away but some here say they don't bother putting that particular bolt back in.

Pics to follow soon.
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Going to cost quite a bit with just a plain rebuild changing the usual stuff.

If the broken casting is part of the gearbox, I think I'd try to source another. Presume this bolt is the one that people swear about - I'd refit it if at all possible. Reckon the casting could have been broken by a bodger thumping the starter motor to get it off. That won't be a problem on my kit car, fortunately.

Regarding bearing sizes etc, I presume you know about ePER? There's an online version at the FIAT forum or various quality CDs on eBAY - some work better than others.

Meanwhile here's the ePER page for the 1997-2002 V6 crankshaft/shells. The image is for the earlier 2.5 engine before they changed the catalytic converters - don't know if the crank is the same but easy enough to check. You can enter the VIN into ePER and it will point you at the right parts, but IIRC not the whole VIN - just the last eight (or maybe that was ten?) digits.

Your flywheel is 8.6 kg. A GTA item is a bit lighter at 8.1 kg if you can get hold of one at sensible money. Early GTV is a touch over 7 kg. The 164 24V flywheel is only 6.9 kg but the 156 toothed ring for the crank sensor would need fitting to the back of this one and I don't know if there are any other "gotchas" to this route either, such as the overall depth or the surface on the back of it. Might struggle to find a 164 24V item now, anyway. Spare a thought for the poor sods with the later softboy GTV who have to put up with the dual mass thing at 14.4 kg!
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(Post Link) post #5 of 12 Old 10-04-13 Thread Starter
Status: The V6 lives! Phew.
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Cheers mudhut.

The 156 will be a keeper so I don't mind spending that bit extra on her.

I know which shells to get now from what you posted, thanks.

I've already cleaned up the flywheel and taken a 10th of the face to clean it up so I'll be using that to keep costs down but cheers anyway.

I'm looking at building a nice sound engine that I wont have to worry about for some time. (He says!)

I'm looking to use the gearbox of my current 156 if that looks ok when I take it off.
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(Post Link) post #6 of 12 Old 13-04-13 Thread Starter
Status: The V6 lives! Phew.
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So I've been giving the last few parts a coat of paint. Just got one of the cylinder heads to do and everything will be ready to assemble.
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(Post Link) post #7 of 12 Old 13-04-13 Thread Starter
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Some more parts.
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(Post Link) post #8 of 12 Old 13-04-13 Thread Starter
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All parts have been either shot blasted, washed in a steam cleaner or cleaned in a parts cleaner so everything is as clean as I can get them. I've sprayed my parts with either Hammerite black or aluminium heat temp paint.

Is it a good idea to use the bearing shells again if they still have their coating on them and look ok?

Same for the piston rings? Best to replace or use again?

Engine had only done 40k.
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Do a test assembly on the crank and measure the clearances first (plastigauge is cheap and accurate). If they are toward the top end of tolerance then get new shells I'd say. Or just get new ones anyway! It's what I always end up doing but is probably overkill most times TBH.

For the rings, if you go for new rings you are going to have to at least glaze-bust the liners. At 40k, probably no good reason to replace them as long as there are no signs of damage or wear.

I'd get (or borrow) a conical ring compressor though - don't much like those band-clamp types. Far too easy to trap a ring/have one slip out just at the block.
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BTW...Hi Peter (Mudhut).
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Nice to hear from you too Chris. Wasn't expecting you to pop up here.
 
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I tend to lurk in quite a few places....
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