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neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Reviews:
·Bright House

New head, old motor

This kind of goes with my Rebuild or Replace thread... but I broke it out into it's own thread because it can apply elsewhere...

Found I am going to have to pull the head on my 99 Passat. Apparently all the exhaust valves are bent. Lovely. Anyway, assuming the head itself isn't damaged, I am going to replace the damaged valves, and then have the head resurfaced. Thinking about having a valve job done at the same time.

Here's my question. I've always been told you don't put a "new" (re-manufactured, or rebuilt) head on a old motor. Something about how the new head seals right and will cause the older block and pistons to wear faster... I have never seen any evidence to prove or disprove this....
--
"F is for Fire that burns down the whole town...
U is for Uranium...... Bombs...
N is for NO SURVIVORS!!!!!" Sheldon Plankton

Keep Calm and Carry On


ironweasel
Weezy
Premium
join:2000-09-13
Belen, NM
kudos:1
Typically when you replace heads on an engine you should at least surface the block itself if not go all out and deck it. You can put new heads on an "old" block and the vast majority of the time it's not a big deal as long as you use a quality head gasket and properly clean and prepare both mating surfaces (block and head).

Is your Passat a turbo model?
--
I'll be stretching out the rhyme like gravity stretches time.


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3
reply to neonhomer
Well, I have quite a bit of experience on this, and I can positively tell you without a doubt, that.....it depends.

Yes, on engines with higher mileage and with more of a history of "neglect", it is possible that any sort of head repair or replacement can increase overall cylinder working pressures, which has the ability to increase blow-by losses past the rings and result in oil consumption increases. There is no effect to piston or block wear.

But if the engine has been relatively well cared for, the problem isn't as severe, and may not have any effect at all. So, there's no single *right* answer, it depends greatly on many other factors.


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Reviews:
·Bright House
reply to ironweasel
Yes, it is the turbo...

The motor has about 180k on it. Pulling the motor to have the deck blocked is not feasible at this time. The head has to come off to be fixed, so I am going to get it resurfaced anyway.

Matt - so far, from looking at the top of the head, it looks to be in okay shape. No sludge that I can see. We were going to pull the head yesterday, but I didn't have the 10mm Polydrive socket to pull the head bolts.
--
"F is for Fire that burns down the whole town...
U is for Uranium...... Bombs...
N is for NO SURVIVORS!!!!!" Sheldon Plankton

Keep Calm and Carry On

PrntRhd
Premium
join:2004-11-03
Fairfield, CA
reply to neonhomer
When you pull the head do look for piston damage as the valves probably bent on them when the timing went awry.


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Yeah. That's a given...


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3

1 recommendation

reply to ironweasel
said by ironweasel:

Typically when you replace heads on an engine you should at least surface the block itself if not go all out and deck it.

That is pretty far from any "typical" head replacement I've ever done. Having a block surfaced or decked is a major operation that requires complete engine removal and dis-assembly which makes it far from being a reasonable addition to a head-job. It only gets done in cases of block damage from a head gasket failure or some other catastrophic failure, or in a high-performance application during the initial build. It isn't routine.


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Reviews:
·Bright House
That's what I was thinking. I've done a couple of head swaps on aluminum head/iron block motors, and all you usually do is resurface the head. Also with this job, new head bolts are a given.

About the valves. I know I have to replace at least all of the exhaust valves. There are 8 of them (a 20v motor). Should I order the valves myself, or let the machine shop get them?

***

Now in my Jeep motor (4.0 inline 6) both the block and head were resurfaced, only because the block was sent to the machine shop to be cleaned and checked. To tell the truth, I didn't order it to be surfaced, but he was halfway through it when he remembered he wasn't supposed to. No harm, no foul... I tossed him a few extra $$ for the trouble..
--
"F is for Fire that burns down the whole town...
U is for Uranium...... Bombs...
N is for NO SURVIVORS!!!!!" Sheldon Plankton

Keep Calm and Carry On


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3
I would let the machine shop get them, mostly because there may be a need to ensure the proper valve stem length in order to achieve the proper valve spring installed height. It isn't something often required, but the shop may want to order a stem length other than standard to make sure they have the right spec. In most cases adjustment can be made with the removal or addition of shims, but just in case I'd leave it to them.

And, it also gets you out of the "Hey you got the wrong parts" call.


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Reviews:
·Bright House
I have been pricing the parts, and I noticed they have two different valves, with two different groove to tip lenghts. One is a sodium filled valve, one is not, and they both come in .157 and .222 lengths. Ugh..

Friend of mine is getting his tool guy to order the socket to pull the head. Will hopefully have it to the machine shop soon.


Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2
reply to neonhomer
Yes, let the machine shop do it.

Request inspection and report first - they supply all parts.
With bent valves can sometimes come damaged valve guides.

That would pretty much make your head a boat anchor.
--


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Thing is I can get a used head off a running motor for $200. I have until Wednesday to get it, but don't know if I need it.


Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2
Why not get the running motor?
This is your 'safest' route.
--


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Because its not likely to be there by the time I have the cash to get it.


Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2
Reviews:
·TekSavvy DSL

1 recommendation

If you are that tight on cash, then I would stop now.

Fixing an engine is a job that is chock full of random $40.00 items that should be replaced.

That used engine is the most realistic chance you have of making the car run on a ~fixed~ budget. Remember that making it roadworthy is a whole other story.
--


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
I'm not looking to throw it on the road ASAP. I can wait and build over time. Its just having $350 for the motor in one shot. (275 + 75 core).


Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2
I'd still say that is the way to go.

Best of luck in any case...
--


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Hopefully we will get the head off this week, and be able to find out if I need the other motor or not.


tallguy11

join:2002-02-08
Edmonton, AB
reply to neonhomer
I agree with Cho BAka just get the running motor and swap the whole thing... 350 for a whole running motor aint bad!


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Still would need to change the timing belt. I think that is what we are planning to do this weekend...


tallguy11

join:2002-02-08
Edmonton, AB
well changing a timing belt aint no big deal especially with having the whole motor outta the car lol


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Right. That's the plan... My friend that is helping me wants to regasket the entire motor.... I just want to get the damn thing running!


tallguy11

join:2002-02-08
Edmonton, AB
just think a little more time and money spent now = alot less time and money spent later!!


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Well, when we put a used motor in a vehicle, we do the usual gaskets... tins, manifolds, etc....

With this motor, I also want to do water pump and thermostat...


tallguy11

join:2002-02-08
Edmonton, AB
sounds like a good plan!


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
It's confirmed... Motor pulling party tomorrow... It's a shame the pick a part yard doesn't include the turbo with the motor.... but oh well...

HarryH3
Premium
join:2005-02-21
kudos:3
said by neonhomer:

It's a shame the pick a part yard doesn't include the turbo with the motor....

You could always just leave it attached and see if the checkout even notices.


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
Oh.. they notice. I tried that one time with a different motor, and a carb. They wanted to charge for the carb ...


neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL
I ended up getting the motor this weekend. Came out of a 98 w/ 150k on it. Timing components are intact, belt looked worn but good. Going to replace it anyway. Also going to replace the valve cover gasket and front and rear main seals.


tallguy11

join:2002-02-08
Edmonton, AB
sounds like u are on the right track to having a reliable car again!