Head warped .014" - bake it or mill it?

Technical questions and answers concerning all models of VW diesel vehicles.

Moderators: Fatmobile, 82vdub

Quantum TD
Turbo Charger
Posts: 613
Joined: Sat Feb 16, 2008 7:27 pm
Location: The Dirty South

Re: Head warped .014" - bake it or mill it?

Post by Quantum TD » Tue May 03, 2011 11:41 am

dkmc wrote:Seems to me.....stretch bolts are supposed to be installed DRY....
Not according the gasket manufacturers. They're supposed to be lubed with a thin coat of conventional oil that has had time to drain off. I use WD-40, but 10-30 or 5-30 works fine. Just lay them on a piece of newspaper and then the excess run off. Do NOT use synthetic (ask me how I know).

vwkook
Diesel Freak
Posts: 142
Joined: Sun Oct 23, 2005 12:00 pm
Location: Milwaukee, WI

Re: Head warped .014" - bake it or mill it?

Post by vwkook » Tue May 03, 2011 3:12 pm

Quantum TD wrote:
dkmc wrote:Seems to me.....stretch bolts are supposed to be installed DRY....
Not according the gasket manufacturers. They're supposed to be lubed with a thin coat of conventional oil that has had time to drain off. I use WD-40, but 10-30 or 5-30 works fine. Just lay them on a piece of newspaper and then the excess run off. Do NOT use synthetic (ask me how I know).

Do tell.
'69 Fasty
'81 Caddy

Quantum TD
Turbo Charger
Posts: 613
Joined: Sat Feb 16, 2008 7:27 pm
Location: The Dirty South

Re: Head warped .014" - bake it or mill it?

Post by Quantum TD » Tue May 03, 2011 10:50 pm

vwkook wrote:
Do tell.
Image

This is the guideline set for the Reinze HG I bought for a 1998 TDI AHU.

The TTY bolts yielded LONG before I had finished the last 180 due to the reduced surface friction from the synthetic. I had to do the job all over with new bolts and a new gasket. Technically, it could have been spot on with the torque, but I didn't trust the bolts anyways (China made).

tylernt
Turbo Charger
Posts: 1360
Joined: Wed Jan 25, 2006 1:12 am
Location: Idaho

Re: Head warped .014" - bake it or mill it?

Post by tylernt » Wed May 04, 2011 12:05 am

Quantum TD wrote:The TTY bolts yielded LONG before I had finished the last 180 due to the reduced surface friction from the synthetic.
Yup, lube affects torque, which is why ARP has you use their special lube.

On the upside, it's nice to hear that the bolt will fail before the threads in the block do. Bolts are cheaper than blocks. :)
'82 Diesel Rabbit • '88 Fox (RIP) • '88 Jetta (work in progress)

the vegenator
Turbo Charger
Posts: 302
Joined: Wed Nov 16, 2005 6:34 pm
Location: Bloomington, IN

Re: Head warped .014" - bake it or mill it?

Post by the vegenator » Fri Jan 04, 2019 3:13 pm

Hey folks! Long time no post. I’m Revisiting this topic after having run my engine build for nearly 60,000 miles. Quick recap: i used a block with the extra drain hole plugged, And used my mechanical lifter head with the water jacket hole plugged with epoxy. Engine runs strong and efficient. The only issue I’ve noticed is a little bit of coolant weeping from the head gasket, But not so much the cause alarm. I just keep the coolant reservoir topped off.

I ended up returning the older hydraulic head in exchange for some parts at the Volksdoktor.

Now that I’m in a better position financially speaking, i’ve been planning out a turbo build for this car. Started sourcing parts, and decided I would like to try and upgrade the head to a Hydraulic lifter head. I picked up an old head from the Volksdoktor and took it to a machine shop - it looks like it’s .015” out. The machine shop I went to doesn’t specifically deal with Volkswagen or diesels, and he wasn’t comfortable baking it back into shape for fear of cracking it. So it seems like I’m in the same position as when I first posted back in 2011. Plenty of good tips and suggestions in this thread from 8 years ago for me to ponder, But if anybody else has any more thoughts or words of wisdom feel free to toss em my way.

Sure I could bolt up a turbo to my 1.6 NA And keep my fingers crossed, But I like the idea of using a sturdier head in general. Hmm....
- Mike Harpring

'85 VW Jetta NA Diesel/WVO

Fatmobile
Global Moderator
Posts: 7413
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa
Contact:

Re: Head warped .014" - bake it or mill it?

Post by Fatmobile » Sat Jan 05, 2019 1:22 am

I like the baking method,.. because I think the prechambers are supposed to sit a little proud.
Machining them down makes the leading edge of the exit hole very sharp and thin.

It is very hard for them to bake and bend a VW diesel head.
My local shop tried and couldn't get it to budge.
They called another shop that bends heads.
They said it should just bend the head straight,... "Unless it's a VW diesel head, those are a real pain in the ass. We put one in the press once and it took something like 20,000 lbs to bend it".
Might not have been 20,000 but I think that's what they told me.

Their setup looks weak with 2 thin bolts supposed to pull it down straight.
I have a cracked block. I'm going to cut the top off and let them try using that with more and bigger bolts.
'91 Golf gasser converted to turbo diesel.
'83 Rabbit gasser, converted to diesel, then converted to run on vegetable oil.
2, '84 GTI projects cars

the vegenator
Turbo Charger
Posts: 302
Joined: Wed Nov 16, 2005 6:34 pm
Location: Bloomington, IN

Re: Head warped .014" - bake it or mill it?

Post by the vegenator » Mon Jan 07, 2019 2:59 pm

Yeah there aren't any shops around that seem to want to mess with heating heads up in philly. I went to the old timer VW mechanic and he said he knows of NO machine shops that will bake, and says even getting them surfaced is a pain because of the precombustion chambers.

He did give me some words of wisdom - don't try to fix what isn't broken. Sure, I have a functional (slightly weepy) mechanical head, but I want to add a turbo. I heard adding turbos to my NA setup is risky. He said I'll be fine as long as I'm not trying to race it. So I may not do anything with this hydro head, especially since it seems too out of spec.

DId I mention my main priority is turning my jetta into a wagon/variant? We'll see how THAT goes before messing around with engine stuff.
- Mike Harpring

'85 VW Jetta NA Diesel/WVO

Fatmobile
Global Moderator
Posts: 7413
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa
Contact:

Re: Head warped .014" - bake it or mill it?

Post by Fatmobile » Mon Jan 07, 2019 11:44 pm

You mean you are going to make a Jetta station wagon?
From my experience 8 thou warp will work, with some hylomar.
There are 2 shops in my little (30,000 people) town that do it,.. but can't bend a VW diesel head with their weak fixture.
'91 Golf gasser converted to turbo diesel.
'83 Rabbit gasser, converted to diesel, then converted to run on vegetable oil.
2, '84 GTI projects cars

the vegenator
Turbo Charger
Posts: 302
Joined: Wed Nov 16, 2005 6:34 pm
Location: Bloomington, IN

Re: Head warped .014" - bake it or mill it?

Post by the vegenator » Tue Jan 08, 2019 1:05 am

If I CAN use the head I will. But for now I’ll wait. .

And yeah I’m diving into a wagon project. Been wanting to do this for YEARS. saw some real world examples online and felt inspired. Ended up finding a good donor golf and already cut off what I needed. Would a post chronicling my build be suitable on this forum? Going to do a vortex post and probably an instagram account.

Image
Image
- Mike Harpring

'85 VW Jetta NA Diesel/WVO

Fatmobile
Global Moderator
Posts: 7413
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa
Contact:

Re: Head warped .014" - bake it or mill it?

Post by Fatmobile » Thu Jan 10, 2019 11:36 pm

Yeah, you can post it in the projects fora.
I know where there's a Jetta and a Golf 2 door.
Not sure I have time for a project like this but it is on the list of my dream cars.
'91 Golf gasser converted to turbo diesel.
'83 Rabbit gasser, converted to diesel, then converted to run on vegetable oil.
2, '84 GTI projects cars

Post Reply