Rebuild the whole engine or just refurbish the head?

Gvr

Member
Joined
Jan 13, 2022
Location
Romania
TDI
2001 Golf Mk4 ALH
I've got this Golf with an Alh engine, bought it a year ago with 320.000 km on it. I did a compression test then, it was like 300psi across, haven't measured it out since. Point is, I was expecting a rebuild or something like that. I've put some China Jettex .230 nozzles in it, changed the Chra on the turbo Gt1749V ( been running 21 psi for 20.000km), so it's seen some abuse.
Now, I think the headgasket is chipped. Though it's not overheating, it builds pressure in the expansion tank and spits it out ( filled with 5l of water in like 1000 km).
If I drive it gently, it doesn't spill out that much. And it's been blowing some white smoke.
I know for a fact that the previous owner didn't take care of the car, so since I bought it I was eager to take the engine apart and see what's happening there.
I'm no specialist, just a DIY 21 year old trying to learn. My only experience with taking an engine apart is my little 125cc Honda that I took apart, that worked. But it's a different kind going to this ALH motor.
Owner said timing was done at 300.000km, and honestly it seems in good shape, writting is still visible on the belt, doesn't look that worn. Can I just change the headgasket without changing the belt ? If not and I have to change the timing belt, is it worth taking doing the whole bottom end ( taking the block to a machinist, changing pistons etc ) , or should I just refurbish the head and throw in a new headgasket?
My only problem would be money, otherwhise I'd start working right now on it tbh..
Also, I'd like to upgrade my turbo to a VNT 17 maybe, should I do pd 150 head bolts? And how does that work, anyways? Do I just cut them to length using a saw, and call it good?
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
ARP makes head studs for the ALH, you'll want to use those. Always a good addition to prevent the issue you're currently having.
I would rebuild the head and keep running it. The bottom end, so long as the hone marks are good and you don't have a bent connecting rod, are usually fine.
Keep in mind, if you do have compression in the coolant, continuing to drive it can etch the block or the head, making it unusable unless it is machined.
 

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
"rebuilding" the engine, if it only needs a hone isn't terribly hard if you've done a head before - i've done it in the gravel driveway. would probably add an extra day. check piston height with dial indicator to make sure they are in spec and none are bent or messed up. drain oil, drop pan, remove piston/rods, cover crank and oil squirters (i used some foam cutouts i made with hole saw to jam down to bottom of piston). i hear crank bearings are generally pretty stout and i bet they're likely fine for quite some time. if you want to change those, then that's a whole nother can of worms... hone it with drill ($60 for a flex hone). clean it all up well, re-install rods/piston with new rings - or with new rods if needed, put back pan. it wasn't as hard as i first thought - i've only done it once. but then you should be pretty guaranteed to have a nearly brand new engine that will have no surprises for a long time - barring any rookie mistakes :D it's what i would do if i were you.

edit - the big decision is whether you think the crank bearings are fine for another 300k+ miles. if you think they are, honing the block if it looks not-so-good isn't too big a deal. if crank bearings are suspect, then of course removing trans is required....
 

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
if the belt is a quality belt as are the tensioner/roller, i would just re-use them. if they are no-name suspect parts, get good ones - like INA, SKF for example
 

Gvr

Member
Joined
Jan 13, 2022
Location
Romania
TDI
2001 Golf Mk4 ALH
"rebuilding" the engine, if it only needs a hone isn't terribly hard if you've done a head before - i've done it in the gravel driveway. would probably add an extra day. check piston height with dial indicator to make sure they are in spec and none are bent or messed up. drain oil, drop pan, remove piston/rods, cover crank and oil squirters (i used some foam cutouts i made with hole saw to jam down to bottom of piston). i hear crank bearings are generally pretty stout and i bet they're likely fine for quite some time. if you want to change those, then that's a whole nother can of worms... hone it with drill ($60 for a flex hone). clean it all up well, re-install rods/piston with new rings - or with new rods if needed, put back pan. it wasn't as hard as i first thought - i've only done it once. but then you should be pretty guaranteed to have a nearly brand new engine that will have no surprises for a long time - barring any rookie mistakes :D it's what i would do if i were you.

edit - the big decision is whether you think the crank bearings are fine for another 300k+ miles. if you think they are, honing the block if it looks not-so-good isn't too big a deal. if crank bearings are suspect, then of course removing trans is required....
Was thinking about replacing the pistons with some ASV ones if I were to take them out. I've heard that a simple re ring job could result in a lot of blow by past the rings..
Might go the extra step
 

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
ASV pistons are nice - they supposedly have better cooling because of how the oil circulation works. i've put them in 2 engines i've rebuilt. i'm not sure about blowby issues by only re-ringing. i don't really see how thats possibly unless you didn't hone it right or install the rings correctly.. but i'm not an engine building guru, i've only done a few myself.
 

Gvr

Member
Joined
Jan 13, 2022
Location
Romania
TDI
2001 Golf Mk4 ALH
What rods did you use with the ASV pistons? I read that the stock ALH ones dont work.
 

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
pretty sure they do... i fit mine on genuine rostens and some china rostens. i'm not 110% sure, but i believe the wrist pins are all the same...
 

Gvr

Member
Joined
Jan 13, 2022
Location
Romania
TDI
2001 Golf Mk4 ALH
Hmm, and I also need to add the bottom oil squirters for the ASV pistons, right? If I'm doing the bottom end, is it okay to take the block for a bore and hone, put in ASV
 

Gvr

Member
Joined
Jan 13, 2022
Location
Romania
TDI
2001 Golf Mk4 ALH
pistons, have the crank polished and drop in new bearings all over the place?
 

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
your block already has squirters and they should be aligned correctly, use a tiny drill bit to confirm. if you feel like really going the extra mile, then yes, remove transmission/flywheel and crank and do new bearings etc.... someone else would know better, but my guess would be crank bearings would be fine to leave in... if you're going to go that far, then might as well get stronger rods too lol... rabbit hole can be deep! :)
 

Gvr

Member
Joined
Jan 13, 2022
Location
Romania
TDI
2001 Golf Mk4 ALH
Thanks for all the info, I'll take the head off and inspect the bores, if they are fine I'll do the bottom part next time.
Another part I have to change is the camshaft, heard that the SDI camshaft has a different profile and can keep the valves open a tad more, is it worth buying that one over the oem one? I understand that oem is made by Kolbenschmidt. I'm also pairing those with Ina black lifters. Headgasket wise, is Victor Reinz okay? I want to make sure I'm getting 'quality' stuff.
 

Mpaw

Veteran Member
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Aug 21, 2018
Location
Germany
TDI
Caddy 2005 1,9 105 ps; Polo 2015 90PS Bluemotion
hi burpod...
can you say more about this: " your block already has squirters and they should be aligned correctly, use a tiny drill bit to confirm "
... how to align them
 
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