News:

Due to a technical issue, some recently uploaded pictures have been lost. We are investigating why this happened but the issue has been resolved so that future uploads should be safe.  You can also Modify your post (MORE...) and re-upload the pictures in your post.

Main Menu

1968 Eldorado 472 oil pan gasket and freeze plugs replacement - engine overhaul

Started by IcebearLars, September 04, 2016, 02:36:45 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Roger Zimmermann

Quote from: savemy67 on September 08, 2016, 08:48:43 PMWhen removing any original bolts, use a torque wrench so that you can make note of the torque required to remove the bolts.  If the removal torque is close to the specified installation torque, it is likely that the bolts have not exceeded their yield point.
Christopher, usually the torque needed to unscrew a bolt is much higher than its specified torque. Your suggestion would be Ok if the bolt(s) were just installed. 
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

IcebearLars

Thanks for all hints - got the engine/tranny today out in one piece, but it was more than tight and the whole unit had to be tilted to the back (tranny down - engine up) to make it happen.

IMG_1743.jpg
IMG_1748.jpg 
IMG_1750.jpg
IMG_1753.jpg
IMG_1748.jpg
IMG_1755.jpg
IMG_1756.jpg
IMG_1757.jpg
IMG_1762.jpg       


IcebearLars


IcebearLars

Did a compression test and the results are 4 pistons at 125psi, 3 at 130psi and one at 165psi - guess I have to do some work on the heads/pistons ???

bcroe

Now that the trans is out, make sure the big
chain cover on the back is not leaking.  The
cork gasket has inadequate clamping area at the
bottom (just where it needs it).  The motorhome
people just glue the cover on, like they started
doing with valve covers about 1977. 

They said use one tube of VALCO, it worked for
me.  Trans out, going to refresh the gaskets
and seals?  Bruce Roe

TJ Hopland

Before you tear too deep I would do a leak down test to see if you can narrow down where the lower compression ones may be going.  Would be nice to know if you need to really look close at valves or if you may be getting into the block.

Are you fairly sure your testing process was as consistent as possible?  You numbers are not that far off so some variable in your testing could explain some of em.


And I have to add something that you will be hearing a lot:

While you are that far in you might as well...............................   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

IcebearLars

Have no leak down test equipment available.

Did the test with a friend and we went through the 8 cylinders twice to check - same results on both runs - so I guess there is no way not to open the heads and/or replace the piston rings - thoughts?


TJ Hopland

You don't really need an official leak down tool set.  Really all you need is a way to get compressed air into a cylinder.  Sometimes the hose off a compression tester can be used,  it depends on the tester and they usually have a check valve/core in em so you have to remove that.

Basically you turn the engine so the piston is down and valves are closed. You do want a pressure regulator to control how much pressure you are putting in.  Sometimes the valve timing won't have the valves fully closed at the bottom of the stroke so you have to move it a bit at which point the air pressure will try and push the piston down. 

Put some air in and listen for where its leaking out.  If its coming out the exhaust its an exhaust valve.  If its the intake its an intake valve.  Crankcase its rings.  A snoop around with a borescope would not hurt either.  You can get pretty decent ones these days pretty cheap.  Way cheaper than what you could end up spending on a partial or full rebuild.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

IcebearLars

Thanks for the tips TJ,

Plan on getting the heads off and lap the valves and get them new valve stem seals as well as the pistons new rings. Have the bearings for the cam shaft ready as well if needed as well as a ton of seals and gaskets I bought in advance. Time chain gets new as well.

Cheers

Lars

TJ Hopland

Ahh so you are basically planning a rebuild.   I thought you were hoping to not go that far.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

IcebearLars

As you stated - while the engine is out ...🤣

But would not call it a full rebuild - will fix stuff I can do easily w/o the need of a shop to mill something - but I don't know yet how the engine looks inside.

 

IcebearLars

New FlowKooler Hi-Flow Mechanical Water Pump is waiting as well to get into the game 🤣
And have bought at OregonPerformance a TH425 rebuild kit - but now first gets the engine some love and attention🤪

TJ Hopland

Take a close look at the shift shaft seal in the trans.  Those often leak and its just an O ring as far as I know, not a lip seal that was more common on other models.

Weld some 1/4-20 nuts on the inside of the timing cover for the small water pump bolts.  Those are easy to strip and often strip and cause leaks.  Plenty of clearance in there and no one will ever see it with the engine assembled.

Order a nut and washer for the crank.  Handy to have when working and setting things up.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

IcebearLars

Quote from: bcroe on March 14, 2023, 06:15:56 PMNow that the trans is out, make sure the big
chain cover on the back is not leaking.  The
cork gasket has inadequate clamping area at the
bottom (just where it needs it).  The motorhome
people just glue the cover on, like they started
doing with valve covers about 1977. 

They said use one tube of VALCO, it worked for
me.  Trans out, going to refresh the gaskets
and seals?  Bruce Roe

Hi Bruce,

thanks for that important hint - hope the Elring Dirko HT works as well - used this on a bunch of other cars directly on motor block areas and works like a charm at higher temps - so I guess it will work on the back tranny cover as well since this gets not that hot.

Cheers

Lars

Chopper1942

Lapping valves will probably be a waste of time.  This was usually done after grinding the valves and seats.  If the motor has many miles on it, the seats will have worn and are too wide for effective sealing and heat transfer.  Since you have the heads off I would take them to a machine shop and have them structually checked for cracks, guide wear and seat condition.  It would be smart to have hardened seats installed at this time.  Unless you are adding a lead additive to the fuel, the original seats will wear rapidly.  The tetra-ethyl lead that was added to regular and premium fuels in '68 raised the octane of the fuel, but more importantly it provided lubrication to the valve seats to prevent the exhaust valves from eroding the seats.  Hardened exhaust seats, a 3 angle valve job, and refreshed guides if needed will keep her running great for a long time.  Check the tips of the rocker arms and the pivots, if they are worn, they need replaced.  Always keep the OE push rod, rocker arm, and rocker pivot together and put back in the same location from which they were removed.  Cadillac used different lenght push rods to adjust the lifter plunger depth for quiet operation. 

The proper way to do a leakage test is to bring the piston to TDC compression. Put air into the cyl. air pressure regulated to about 70 psi.  Without a regular leakage tester, you will only hear or feel where there is air flow.  The problem is that there is always leakage in a sealed engine around the rings.  The leakage tester will tell you the percentage that is leaking.  A well sealed engine will leak 2-5%, normal is as high as 15-20% depending on mileage. Anything over 20% is an issue.

Another side note, is your oil.  In 1968 engine oils had zinc as an additive to prevent lifter and camshaft failures.  Zinc is detrimental to catalytic converters and was removed from oils in the '70's.  You would be smart to add a zinc additive to the oil at each change.  You can get it at most parts stores, Summit Racing, and Jeg's.  I still have some "old oil" that I am using up in my '79 El Dorado.  Today's oil are much better, so use them with a zinc additive and your valve train will love it.

IcebearLars


TJ Hopland

Just curious if anyone has ever seen major seat issues on one of these engines?  I never have.  I heard the reason was they were high nickel castings so it just wasn't a problem.  Cadillac could afford to spend an extra $1 per casting.  The Fords and Chevs of the world couldn't do that so their castings were not as good till they had to be. It also helps that Cads were not typically revved as high or pushed as hard as some others.

If there are seat issues ya you have to deal with them but I don't think I would have seats put in unless there was major issues that don't come out with a standard clean up.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

IcebearLars

Before I start disassembling the block to overhaul it I want to flush the coolant channels inside the block - where should I best connect my garden hose to flush the whole system? Remember I had to take the water pump already off - that said the coolant circuit is for sure interrupted and therefore I maybe have to connect my garden hose to more than one hole?

shadetree39

Re: the freeze plugs. My local independent auto store has a huge Dorman supply and he typically sells the the plugs .015 (1/64") oversize for example; the 9/16 opening for A.I.R. in the heads would take a 37/64 plug.
Had to drive them in.
Lou Aug #33894

IcebearLars

Quote from: TJ Hopland on March 15, 2023, 01:24:03 PMWeld some 1/4-20 nuts on the inside of the timing cover for the small water pump bolts.  Those are easy to strip and often strip and cause leaks.  Plenty of clearance in there and no one will ever see it with the engine assembled.

TJ - have the water pump section of the 68 shop manual not in front of me but know from disassembling it that it had 3(?) different bolt sizes to bolt the water pump to the block/timing cover.Which ones are we talking about to get the nut(s) welded on the inside of the cover? Since the ones on the outer ring bolt into the block I guess it are the ones I marked in green? Are they all 1/4-20?

Next question I couldn't ask from the far (this week not in front of the manual nor the engine) what the part is I marked in red - seems to be like a ventilation pipe between the two heads???
How do I get that thing off w/o breaking it?

2023-03-23_09h30_40.jpg

Thanks!