Engine rebuild

Chat about your MKI or MKII Polo (86 and 86F)
GroovyCarrot
Sponsor
Posts: 2305
Joined: Fri Mar 26, 2004 7:35 am
Location: Saffron Walden, Essex

Engine rebuild

Post by GroovyCarrot »

This week I'm going to be taking out my engine and rebuilding it replacing all of the parts which will be worn by now.. on my list of parts to replace are:

Gaskets (full cylinder head set, sump)
Piston rings
Main bearings
Valve guides

However, seeing as this is the first time I will have even considered doing this kind of thing, I'm a bit lost as to the parts I should be buying. In particular, valve guides come in 36.5mm and 42.5mm types and I don't know which size I need, and main bearing sets are sold in 0.25mm, standard or standard with oil hole (all of the parts are coming from gsf). Can anyone help me out on this? I'm sort of learning as I go along really, I'm a bit clueless right now :) Also, any other suggestions of parts that I should replace while I'm at it would be appreciated. Clutch / gearbox parts can wait until I fit a 5 speed box to it, but I'd like to get the engine up to scratch while it's out.

Thanks for any help.
Tahrey1043
Bling Bling Diamond Member
Posts: 5184
Joined: Thu Sep 18, 2003 1:15 am
Location: Birmingham! Enjoys: The pseudo-G-Smiles provided by a 1.6 Megane Sport valver...
Contact:

Post by Tahrey1043 »

yikes.... is it running a little rough?
hardhitter
Moderator
Posts: 1249
Joined: Mon Oct 14, 2002 10:35 pm
Location: Derbyshire 3F Guru
Contact:

Post by hardhitter »

It depends how thorough you are going to be with the rebuild. You can easily spend a few hundred quid on bits for rebuilding your engine. I would recommend genuine vw parts as you know they will be right. GSF stuff is probably ok, but you get the wrong part somewhere etc. they might not have all you want etc. Leave yourself more than a week to do it, as waiting for parts takes a lot of time.

From the top of my head here are a few bits that should be repleced for a thorough engine rebuild; crank bearings, thrust washers, con rod bearings, oil pump and gasket, sump gasket, crank oil seal, piston rings set, head gasket set (which includes all top end gaskets, seals etc).
Theres lots of other bolts, gaskets and seals I've probably missed out but you might want to read haynes to get some idea. I would put a new clutch on now rather than later.

If you aren't very clued up right now, you might want to look into it and learn more before actually attempting it.

hth
Gareth_GT_Hatch
Platinum Member
Posts: 1116
Joined: Tue Mar 09, 2004 9:04 pm
Location: Manchester Drives: '83 GL Classic

Post by Gareth_GT_Hatch »

Ive looked at the parts list on the GSF site and they dont stock the full range of bearings. If i was gonna rebuild my black GT's engine I would probably have to go to vag to get the right size bearings as one in particular is very warn. You will need a good set of feeler gauges to find out the size of the new bearings you need.
GroovyCarrot
Sponsor
Posts: 2305
Joined: Fri Mar 26, 2004 7:35 am
Location: Saffron Walden, Essex

Post by GroovyCarrot »

I'm doing the rebuild this week because my sister's on holiday for a while so she's lent me her *shudder* corsa to run about in while it's in pieces. Don't really have enough money to redo absolutely everything that could possibly be wrong with the engine, but I know that it's burning oil so I'd like to get that sorted, and I would imagine the head gasket will be getting pretty weak by now so I'll get that done. The clutch isn't actually showing any signs of slipping yet, so that's on a back burner until I have more cash and can do everything gearbox related in one go. I'm doing this more for the experience than anything else.. I tend to be pretty fearless about ripping things apart that I have absolutely no idea about whatsoever and learning as I go along :D

I've taken a look through haynes, but it doesn't seem to give any of the sizes of the components that I'm a bit lost over.. I guess I could go to VW, but in my rather limited experience of them they're something of a rip off and I tend to go elsewhere if possible.

As I said before, this is very much for the experience rather than for any desperate need to get these things fixed.. I'll be off to uni september next year, and I'll have to sell the car when I go, so it hasn't got to last all that long :)
Tahrey1043
Bling Bling Diamond Member
Posts: 5184
Joined: Thu Sep 18, 2003 1:15 am
Location: Birmingham! Enjoys: The pseudo-G-Smiles provided by a 1.6 Megane Sport valver...
Contact:

Post by Tahrey1043 »

mebbe just change one most-likely thing at a time til it stops burning oil in that case :roll: and sell it to someone who might have a bit more handiness?

fair play tho for getting down and dirty, i wouldn't dare do something like that because i know it'd end up a total disaster!
GroovyCarrot
Sponsor
Posts: 2305
Joined: Fri Mar 26, 2004 7:35 am
Location: Saffron Walden, Essex

Post by GroovyCarrot »

You mean, take the engine apart, change one bit of it, put it back together, refit it, find it hasn't fixed the problem, take it out, take it apart again, try another bit... much rather get it all done in one go :)

I wouldn't even be considering doing this if my sister wasn't going away for a month and if I wasn't curious about how all this stuff's done.. everything works perfectly well (apart from the oil burning, but that could be worse), I just want to get some kind of experience of all this.

If I get completely stuck on anything, my dad's got a fair bit of experience of this sort of stuff so I'm sure he'll bail me out anyway :)

Still haven't found these measurements anywhere though :(
User avatar
bstardchild
Moderator
Posts: 3057
Joined: Sun Mar 28, 2004 9:53 pm
Location: Norfolk - "Its just Black & Dirty"

Post by bstardchild »

GroovyCarrot wrote:I'm doing the rebuild this week because my sister's on holiday for a while so she's lent me her *shudder* corsa to run about in while it's in pieces. Don't really have enough money to redo absolutely everything that could possibly be wrong with the engine, but I know that it's burning oil so I'd like to get that sorted, and I would imagine the head gasket will be getting pretty weak by now so I'll get that done. I tend to be pretty fearless about ripping things apart that I have absolutely no idea about whatsoever and learning as I go along :D

As I said before, this is very much for the experience rather than for any desperate need to get these things fixed.. I'll be off to uni september next year, and I'll have to sell the car when I go, so it hasn't got to last all that long :)
Fair play to you but.......

Does it smoke on acceleration or on lift off deceleration

On acceleration will normally be rings worn or past sell by date

On deceleration will normally be stem seals and if they are gone it's unlikley that the valve guides are gone cos they will have been well lubricated!!!!!

I'd leave the bottom end (by that I mean mains and crank regrinds) alone if possible

- chuck a new set of big end shells on the bottoms of the rods (vernier caliper will help you measure up and get the right size if they aren't stamped up)

- Clean the pistons with oven cleaner (old trick brings em up like new)

- hone the bores with a DIY honer - don't go mad - they do remove metal :lol:

- Slap on a new set of rings to your newly cleaned pistons

- Skim head

- Replace stem seals and lap in the valves ( or get the firm that does the skim to re-cut em for you - saves blisters on the palms of your hands which are always difficult to explain to mothers, sisters or girlfriends - in fact anyone of the opposite sex!!!!! :oops:

- Rebuild using new head bolts

Just be really clean and methodical - I rebuilt a Lotus Carlton Engine a while ago and that had 24 valves, 6 Cylinders & 2 turbos - you just bit the bullet and take your time make sure you bag everything up to identify it and where it goes and if you have access to a digital camera take photos lots of em as you go along - god they help when the haynes doesn't!!!!!

Good luck
User avatar
bstardchild
Moderator
Posts: 3057
Joined: Sun Mar 28, 2004 9:53 pm
Location: Norfolk - "Its just Black & Dirty"

Post by bstardchild »

PS forgot to say shouldn't cost more than £175-£200 and that includes the parts plus the machining work.....

Head gasket for the LC cost me that much even before I'd started!!!!
GroovyCarrot
Sponsor
Posts: 2305
Joined: Fri Mar 26, 2004 7:35 am
Location: Saffron Walden, Essex

Post by GroovyCarrot »

Thanks for that lot, I'll bear it all in mind :) The lotus carlton sounds like a hell of an engine to overhaul.. bet it was worth it though..

Btw, it occasionally smokes on harsh accelleration, and particularly if you rev it before it's had a chance to warm up properly.. guess that's the rings then rather than the valve guides. One less thing to worry about :)
User avatar
bstardchild
Moderator
Posts: 3057
Joined: Sun Mar 28, 2004 9:53 pm
Location: Norfolk - "Its just Black & Dirty"

Post by bstardchild »

GroovyCarrot wrote:Thanks for that lot, I'll bear it all in mind :) The lotus carlton sounds like a hell of an engine to overhaul.. bet it was worth it though..

Btw, it occasionally smokes on harsh accelleration, and particularly if you rev it before it's had a chance to warm up properly.. guess that's the rings then rather than the valve guides. One less thing to worry about :)
OK - so rings is a must - guides can be left unless really sloopy when you take the valves out to replace the stem seals!!!!!

Yeah I completely rebuilt the LC lump 91 K miles cos it had a cracked head and was misfiring like a t**t under load and with a refurbished head new head gasket and a bottom end rebuild it ran like a peach afterwards and has since for the new owner......

Trouble is I didn't learn me lesson and ended up with another :oops: still it only had 21K on the clock when got it so I've got a while before i have to do it all again......

Just remember someone built it originally so if it went together it must come apart and at the end of the day it's all just basic bolts and blocks

kinda like lego with oil and grease!!!!

Thats probably why I have a 3.0 24V Six cyl engine taking up most of my garage

- block on stand with new rings on cleaned pistons in honed bores on new std big end shells without touching the mains or crank.

- Skimmed Head on another stand on the bench with fully flowed inlets - matched to within 5ml of each other with freshly cut valve seats & new stem seals waiting for the final light grind

- Big box of parts beside both with all new camchains and tensioners and gaskets

Total expenditure on engine to date has been £800

And a car outside which has clearance above the tyres to the arches I could fit my head in let alone 3 fingers
Tahrey1043
Bling Bling Diamond Member
Posts: 5184
Joined: Thu Sep 18, 2003 1:15 am
Location: Birmingham! Enjoys: The pseudo-G-Smiles provided by a 1.6 Megane Sport valver...
Contact:

Post by Tahrey1043 »

except the best bit about legos was you could build it any shape you wanted and it didnt end up exploding when you didnt follow the instructions exactly :)

yeah groovy thats what i meant, lets see you sweat :D theres always the "change lots of stuff" method, but when something goes t**s-up after you've put it together again and have changed 5 things, which of the 5 is it? i've learned this lesson the really brain-taxing way with building/fixing computers.... (not as scary that - far less moving parts and manual dexterity needed, just more brain steam)

suppose it can't be "that" hard - flicking past the american chopper program again, there was a bloke there who got a 40hp harley (?) engine basically as bits, had it in a state where you could get the crankshaft whirling by pushing on the piston links within about 20 minutes, and had the entire caboodle spinning and chucking out a fair amount of fizz (and rort) in less than an hour and a half!
thats experience for you i guess, but quite a demonstration.. (and if it all goes pear shaped, you could get him to build you a new one of them with a slightly sportier cam and compression for 45-50 horse, fab up some body and transmission mounts, and have it on a transatlantic pallet the same evening :D)
GroovyCarrot
Sponsor
Posts: 2305
Joined: Fri Mar 26, 2004 7:35 am
Location: Saffron Walden, Essex

Post by GroovyCarrot »

Thing with lego is that it doesn't have to pull 710kg and my own fat arse to town and back every day :D

I think building and dismantling computers was what instilled this somewhat fearless nature about fiddling with things into me.. I'm just a believer that anything that could possibly go wrong can be fixed, and if it can't, I could almost certainly break the rest of the car and sell the bits on ebay for twice the selling price of the whole thing anyway so it's not that big a deal :) Plus.. my neighbour was involved in a bit of a pile up the other day.. someone t-boned his pristine mk3 1.3 genesis and I think it's going to be a writeoff by the sound of it.. I'm considering approaching him about his rather nice engine and 5 speed box, it'd make rather a nice conversion if all this fails :D
Karl_CLCoupe
Platinum Member
Posts: 1131
Joined: Thu May 06, 2004 11:43 am
Location: Southport AKA: Mr Sambuca
Contact:

Post by Karl_CLCoupe »

It would, especially if the rumors surrounding the use of NZ lumps in 1.3 Genesis' are correct. Hmmm wonder what other bits and bobs I could get from a Genesis. Ahhh yes, the rear bench and door cards, then I can get Scirroco II GT front seats, and voila a nice comfy, slightly sporty interior.

Karl.
Tahrey1043
Bling Bling Diamond Member
Posts: 5184
Joined: Thu Sep 18, 2003 1:15 am
Location: Birmingham! Enjoys: The pseudo-G-Smiles provided by a 1.6 Megane Sport valver...
Contact:

Post by Tahrey1043 »

Thats a shame :(

Hopefully whoever did the hitting was in an M5 and came off worse for wear!

Take the engine and gears, man :D If you can figure how to put an ECU, (multipoint?) injection and breakerless coil into a Mk2 and sort out all the wiring-loom stuff. (engine and transmission swap, now there's an education for ya... got a torque wrench?)
Post Reply