Hey guys. My Turbo 617A's fifth cylinder has been leaking for a month or two, no oil in the coolant yet, but a small drip of oil comes out the very back. Im sure its not the valve cover.

Im going to replace the head gasket and timing chain (5 degree stretch) together and before I do this job I want to assemble all parts.

If anyone has any links, Id love them. The ones Ive read have been helpful.

So for parts I want to do complimentary jobs too so my list comes out to

*the turbo and manifold bits

And the for the head
*new head gasket
*special head bolt socket
*new head bolts and washers (how many types and how many per type?)
*copper coat for metal gaskets
*thermostat gasket
*valve cover gasket
*new valve stem seals
*new valve guides
*new valve adjusting nuts
*monark glow plugs
*injector heat shields and return line

I am going to have the head inspected and (milled?) I am also going to port it and paint it. But I am not going to have valves lapped or any complete rebuild because ive heard a rebuilt head is counterproductive for a used diesel motor.
Also valve springs are brand new as of 6 months ago.

For the timing chain

*Jiwis brand timing chain and master link
* new tensioner spring or new tensioner?
*new rails (how many and which?)
*tensioner gasket

And new oil and a filter &
Frësh coolánt

What am I missing? [besides time, money, and energy.]
Thank ya as always!

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A junkyard is not for junk

If you are getting it milled you will need to remove the prechambers. A special slotted socket and a slide hammer is also required with the special adapter. For reassembly over size seals will be required for the prechambers.

I never heard that about valves and a older diesel.

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92 e300d2.5t
01 e320
05 cdi
85 chev c10

@dieselbenz1
How necessary is milling? Is it an absolute or only required if the surface have advanced wear?

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A junkyard is not for junk

So...what's the point in not getting the valves looked at? You're doing everything else for a rebuild so your own argument is working against you

It's also a lot of work just to fix an oil drip....

If you do go ahead, not many people are aware that you can re-use head bolts if they still meet the specs in the FSM....a common misconception that they must be replaced (as with FW bolts)


If I were you I'd weigh up whether its worth it- and as for the argument on rebuilding the head, it really depends what your compression is - below around 300 you probably shouldn't bother doing anything on the head at all, above that the engine will still be worth doing the whole head, but still if there's just an oil weep I wouldn't bother even then....

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1978 300D, 373,000km 617.912, 711.113 5 speed, 7.5mm superpump, HX30W turbo...many, many years in the making....
1977 280> 300D - 500,000km+ (to be sold...)
1984 240TD>300TD 121,000 miles, *gone*
1977 250 parts car
1988 Toyota Corona 2.0D *gone*
1975 FJ45>HJ45
1981 200>240D (to be sold...)
1999 Hyundai Lantra 1.6 *gone*
1980s Lansing Bagnall FOER 5.2 Forklift (the Mk2 engine hoist)
2001 Holden Rodeo 4JB1T 2WD

The whole idea behind completely rebuilding the head and getting perfect seal on the valves being counterproductive is that the blow by gasses that would get past, would now be forced downwards and the pressure would go out the lower seals. Ive got a leakless 617, beside that head gasket and the turbo drain. If you got a rebuilt head you should have a rebuilt block. Thats as far as I understand it.

My compression is 370 avg 390 except on #5, the leaking one, which is at 315. Which is where the *small* oil leak is. I think i may be burning coolant too, which is a big no no considering im running waterless coolant which isnt as cheap as oreillys zerex stuff.

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A junkyard is not for junk

Who told you that? If you have the head off and you're going so far as to replace the valve guides, you MUST have the valves ground at an absolute minimum. Otherwise, they're no longer going to seal.

The top end (head) has nothing to do with blowby. Blowby is gas escaping past the rings. It comes out the valve cover because the bottom end and top end are linked by oil drains and the front cover. All the gas collects in the valve cover and people mistakenly think it's coming from the head. It isn't. If you're gonna R&R the head, do it right or don't do it at all. Half-assing it now will cost you more later that it will cost to do it now.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Have you tried to re-torque the head bolts near the leak to see if it will stop it? A lot less work than pulling the head.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

" a cylinder head overhaul on a high mileage diesel can make matters worse (ie, a tighter seal at the valves can often stress the lower end of the engine and lead to increased blow-by and piston / rod bearing wear. "
Bergsma says it again in some videos too.

I dont "half ass" anything on this car. Everything I do on it gets the full bore of my 155 gun heavy 1st rate 4 masted buttocks of the line.

If new valve guides are going to lead to improper valve seating but perfect valve seating is going to lead to increased blowby and stress, what do I do?! My valve guides felt "okay" when i did the springs, should I just recheck them when I pull the head and for- go doing the guides?

Funola, that was my initial idea, when i get the tool for it I will retorque and test it, untill then im trying to compile a comprehensive parts and tools list.

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A junkyard is not for junk

Yeah, I don't buy that argument. The valves are *SUPPOSED* to seal. That's their job. If they don't, you get low compression, eroded valve seats and valves, loss of power, etc etc.

If the valve guides aren't loose you can probably leave them be for now. I don't think the 617's are known for eating valve guides like the 603's are since they use rocker arms instead of bucket tappets. If they're loose, or the valve stems "wobble", they probably need replaced.

When you get the head off, check the valve seats and valve faces for pitting or erosion. If you find any, you know you need valve machining done.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

You may be getting into a bit of overkill. A tighter seal at the valves only would affect the sealing of the rings of a worn out engine which would already be burning a significant amount of oil.
The term "blow-by" is often misused and some of the "testing" is very questionable. A diesel engine doesn't produce much vacuum and therefore has a tendency to weep oil because of less crankcase ventilation.

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Sam

84 300SD 350K+ miles ( Blue Belle )

Did you do a wet compression test? That would also answer whether your valves are sealing ok (not bother doing any valve stuff at all) or leaking slightly. As said before if they are leaking then not getting them done is silly as they'll only get worse...

__________________
1978 300D, 373,000km 617.912, 711.113 5 speed, 7.5mm superpump, HX30W turbo...many, many years in the making....
1977 280> 300D - 500,000km+ (to be sold...)
1984 240TD>300TD 121,000 miles, *gone*
1977 250 parts car
1988 Toyota Corona 2.0D *gone*
1975 FJ45>HJ45
1981 200>240D (to be sold...)
1999 Hyundai Lantra 1.6 *gone*
1980s Lansing Bagnall FOER 5.2 Forklift (the Mk2 engine hoist)
2001 Holden Rodeo 4JB1T 2WD

Unless money is the issue, there is no reason not to have a complete valve/ valve guide job done when the head is out. It is one of best repairs on a diesel.

Simple test: remove some of the valve stem nuts on the exhaust side and the spring retainer. Wiggle the valve stem. If you see ANY movement you should get a complete valve job.

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