To Rebuild Or Not To Rebuild...

[Rob Thomson 6]

Those of you who are following my exciting rebuild thread will know, my trusty 1.6 GTi is currently on stands in the garage having a vaguely thorough rebuild.

 

I didn't plan to do too much to the engine. I knew the headgasket was just starting to go, and whilst doing that it made sense to do the cambelt, tensioner, waterpump and anything else that came apart along the way. But I didn't plan to do anything to the bottom end as it didn't use any oil, didn't smoke, had decent oil pressure and seemed quite happy revving its nuts off all day long. I thought a bottom end rebuild would be one step too far.

 

Yesterday I whipped the head off the engine. I'm really quite surprised how good the engine seems; all the water and oil galleries are clean and shiny, the cam's perfect, the cam followers are perfect... There's almost no visible wear on the bores; there's no wear ridge, the honing marks are still visible. The only visible sign of wear is some light scoring on Cylinder 2...

 

 

This was barely visible to my eye, the camera flash makes it look much worse. I couldn't feel anything with my finger tips.

 

My first instinct was to say, "f*ck it, that's fine, let's get the head back on..." but then I thought it seemed a bit silly not to rebuild the bottom end while the engine's sitting on its stand in my nice warm garage. I'm a bit nervous, though. Firstly, while I'm quite happy with headgaskets and cambelts, the bottom end strikes me as being a bit too easy to f*ck up. My only experience of a rebuilt engine - albeit one rebuilt by LAD - wasn't a good one; it used more oil than petrol and had extremely dubious compression. I'd rather have a slightly worn engine that was assembled by Peugeot and still works well enough, than one bodged together by someone who doesn't have a clue what they're doing...

 

So - in the grand scheme of things - how bad is that scoring? Does it warrant a rebuild? How easy is a bottom end rebuild? And how likely is it to work?!

 

Thanks, Rob.

[j_turnell 137 3 Cars]

If you cant feel a ridge atall and the scoring is that minor then it shouldn't be a problem. However for piece of mind and if you have the time and a bit of cash then i'd rebuild it. Its pretty straight forward tbh, as long as you mark everything, make sure its all spotlessly clean and do things in the right order then you can't go worng really. Worth while getting if you havent already things like piston rings clamps, hone attachment etc. Not sure how well the Haynes covers this but there are plenty of people on here who've rebuilt engines including myself so if you get stuck just ask.

 

cheers, James

[Tom Fenton 1,542]

I personally would leave the pistons and bores alone as they look OK to me. If you do decide to do anything with it have it honed properly at a machine shop as you will not achieve a decent surface finish with one of the drill mounted DIY honing tools. Then fit new rings to your pistons. If you are going to that extent then also have the crank checked for size and polished or reground as required at the machine shop, then build it all back with new bearing shells.

 

Did you compression test it before you took the head off?

[James_R 3]

Like you said it ran fine before so why touch it 1600's seem to go on and on and on, just took a 150k miler apart and the bottom end's fine so the head, it's amazing.

 

James

[James_m 0]

I think i would leave the bores and pistons rings alone, but maybe have the sump off and change the big end bearings. Its inexpensive, and not especially time consuming if its already on a stand.

Would be a shame to have it all out now ready for any work, then to have the bottom end fail after a few k miles....

Interesting you say the 1.6's seem to go on and on James. My experiance of 1.6's is limited, but i cant ever remember anyone on here complaing of big end knocks compared to the probably hundreds who have had a 1900 engine fail....(both 8 and 16v)

But maybe its just my memory being selective.

[Rob Thomson 6]

Thanks Chaps.

 

I did compression test it when I first had it, and all four cylinders were fine and very similar. With your reassurances I'm leaning towards leaving it alone. I'll sleep on it...

[Miles 331 1 Cars]

If it isn;t broke don;t fix it, There is allot to be said on that one, But I would check the big and main bearings but if they look OK just use them again,

If the bore's are worn allot honing them will do nothing bar show up a ridge up the top which will make them scrap