Rear main bearing oil seals (yet again)

[ardiesse]

I've started a rebuild of an EJ motor, and in cleaning the cylinder block in preparation for reassembly, I found that the rear main bearing oil seal had been cemented into the groove, in both the block and the rear main bearing cap.  The main bearings are stamped "HOLDEN" with no other markings, so they're original, standard size.

I'm thinking that the main bearings and rear seal have never been replaced. Which means that the rear main bearing oil seals were cemented in place at the factory.  I'm no adhesives expert, but the cement is not completely hard-setting.  It reminds me of mastic cement, or the adhesive that the factory used to glue interior trim in place, and headlinings to the window openings.

Questions, questions . . .

Was it GMH practise to cement the rear main oil seal in place?
Any guesses as to the type of adhesive used?  (Something that doesn't set hard, is oil-resistant, and tolerant of high temperatures.)
Has anybody else come across cemented rear main bearing oil seals when stripping a motor down?

Rob

[my8thholden]

G'Day Rob ..
I don't believe rear main oil seals were glued in place in the factory ,but the temptation to do so is huge ,as we all know a lot leak , in back of our minds we are half expecting it to happen and a 50yr plus old motor ,how " original " can it be in every respect ..so I guess the reason you are wondering about whats correct and what works is your fear of not having a problem down the track ,and its a bugger if its wrong as its in the car when it happens and not simple to remedy ..Be assured I went through the same thing last year when I built my FC engine ,its one of the "MAIN " reasons I built the test rig and ran the engine on it several times.I personally don't believe Grey motor rear main oil seal design was one of GMH's brilliant achievements. .Its been few months since I started it ,so now Im going to fit the finished gear box and run it again ...I used Permaseal gasket set to rebuild ,the rear main bearing material is not the same as the old stuff ,its a real bugger to cut as its not finished to size ,my guru mate told me the old asbestos type seals resisted " burn ' asbestos is heat resistant stuff ,you can " overcrush " modern seals and increase friction and " burn " the seal..they leak between the shaft and seal not the seal and its mounting groove ..fit your crank no seal ,get a good feel by hand ,,fit your seal ,tap it well into place ,remove rear main cap and trim excess ,maybe several times ,oil it and "feel" ,should turn by hand with slight drag..I used Permatex No.3 cement on sump gasket ,another area of extra care ,and don't over tighten,put cement in " through " holes and threads..cheers Vern ..

[my8thholden]

Rob ..  A few more thoughts ..The Grey engine ,you no doubt are aware ,have side plate ,timing cover ,sump ,rocker cover oil leak problems...and is some what assisted by modern day oils ..rubberised cork gaskets are not designed to be " crushed to death " ,check your components are true and flat ,I would sit your sump on the block ,no gasket ,and check it ,that it sits flat ,does not rock ,is not touching on inner edge but a gap on outer edge ,where some one levered it off block somewhere in its life ,a nice flat even seal is what you want ,"""DONT """ over tighten ,leave a few days and tighten 1/4 turn ..then when engine operating cork swells a bit and should be good seal ..Vern

[ardiesse]

Vern,

I spent quite some time tapping the sump rails flat.  They do bulge up around the bolt holes, and more so if the screws have been over-tightened.  Same thing for the pushrod cover and timing gear cover too.  And I laid the rocker cover upside down on a bag of sand, and put a big socket and extension over the stud holes and went to town with a big hammer in an effort to un-distort the rocker cover after the nuts had been way over-tightened.

When I rebuilt my FC's motor, the rear main bearing oil seal spun in its groove after about 50 miles.  Which was a real shit to strip the motor down again and replace the rear main oil seal.  I've noticed that the new rear oil seals are different from the originals, and to me they're much more difficult to trim to size.  Still in two minds about what to do.  After the spun rear seal fiasco, I was told to soak the seals in oil for 24 hours before installing.  Good advice, but it makes for really messy assembly.

And oil leaks on newly rebuilt motors is why I built a test stand . . .

Rob

[Fraze]

I went through all of this a couple of years ago, had the engine out several times before getting the rear seal to work,including a spun seal. Eventually I gave up on the rope seal supplied in the gasket kits. The one I tried to use looks like a woven sleeve filled with strands of material which is almost impossible to trim with a razor blade. Eventually i got onto a seal from BestGasket in USA. It is 6380S which is nearest in size and appearance to the original. It looks exactly the same as the rear seal supplied for Holden V8 engines but larger cross section. Since using that, i do have a bit of a drip from the rear main but not much and I attribute that to wear in the sealing track on the crank.
MY wifes nephew did his apprenticeship with Repco as an engine builder in the reco shop, and later worked in the same role at RPM engines. His recommendation (for non asbestos seals) is to soak the seal in oil before fitting, dimple the bottom of the seal groove in the block and bearing cap using a centre punch, then cement the seal in place using ,say, Permatex or one of the oil resistant silicon based products. Incidentally I showed him the rope seal from a new gasket kit and he laughed at it and said that there was no way he would use it. He also said that when they went away from asbestos seals they had a lot of trouble with seals on Holden engines and solved it by using a Ford rope seal but couldn't remember details. Hope this helps, Fraze

[ardiesse]

Fraze,

Yes, I remember your efforts from a couple of years back.
Craig on the FB/EK forum also suggested a centre-punch and Permatex, so it looks like that'll be the way to go.

Rob

[my8thholden]

Gents  ..We are all experiencing the same dilemma ...I confess ,I did put some Permatex on the seal and the housing ,just a smear ,my logic ? what harm can it do !! Fraze ..Yours leaks a little now since you overcame the problem of seal spinning in housing ,I would suggest that shows a little oil making its way through ,there by lubricating the seal as it goes ,its striking the correct balance ,too much clearance too big a leak ,not enough ,"burn" the seal ,picks up on shaft and spins ...so the little bit of oil leaking at rear main would be normal ..I am sure in the 1950's it was considered perfectly normal ..the engine I re built was caked with silicone all round the rear main and front timing cover ,obviously a in car attempt by some one to try and stop oil leaks ..I am going to run my engine on the test rig quite a bit now , if it fails ,its an opportunity to fit Harvs head gasket as well ,I don't want to pull it down to fit new head gasket ,as it has a new one ,but not the improved one ,so it will just sit on shelf ..not totally comfortable with that ..have a good radiator and water pump ,very clean water jacket ,and will use soluble oil in water ..thousands of engines worked for years without improved head gaskets ..I'll let test runs tell me..cheers Vern ..

[hsv-001]

Back in the day at the first garage in Jimboomba ,my Brother-in-law and I would find a socket [we had it marked] that could take the place of the crankshaft so we could trim the rear main seal without the fear of damaging the crank or ourselves fitting and refitting until correctly trimmed .

[old-blu]

  Another suggestion to  ease the frustration. Don't overfill the sump.  Run the oil level just over 1/2 way between the "add" & "full" mark.  Kevin.

[ardiesse]

I have acquired a 6A6 seal installer (thanks Harv).  With it, a really sharp knife and a pair of flush-cutting side cutters, it "only" took one and a half hours to install the rear main bearing oil seal.  Plus I "blue-maxxed" the seal in place.  Let's see what happens when I start the motor up.  Fingers crossed.

I think I've lost my touch.  Couldn't install a piston to save my life.  Every time I tried, the oil ring rail snuck out between the ring compressor and the block.  Currently have worn piston pin troubles.  I have a set of second-hand oversize pins, and I'm wondering how much trouble it is to ream the piston pin bush (conrod) and bores (piston) to suit the oversize pins.

Rob

[my8thholden]

Rob ..Im not really keen on half full sump ...Your piston pin problem ...HMMMMM!!!! .it is usually the little end bush in the rods , not the pin holes in the piston ,you said the O/S pins you have are second hand ,how do they mic up ? How do your standard pins mic up ? original Holden pins are .7503" to .7508" dia ..If they mic up ok then test fit them in piston , then test fit in the rod ,its probably there you will find the clearance excessive ,re bush the little end of the rod ,if you don't use pre finished bushes then you can ream to suit each pin ,Vern ..

[ardiesse]

Vern,

The "oversize" pins are about 0.751" dia in the unworn sections, just over 0.750" where they fit the piston, and about 0.749" at the middle.  So they're probably too worn to be of use.  The "standard" pin I measured (no.1, which is the worst) was 0.749 where it fits the piston, and 0.7465 where it fits the small end bush.  Bush was oval: 0.750 across and 0.7515 up and down.  Which means about 0.004" clearance of pin in bush.

Took the pistons, rods and "replacement" pins to the engine shop this morning.
First piece of advice I got: honing the piston pin bores out to take oversize pins is a job for the specialists.  It's expensive and should only be attempted with new, oversize pins.

As you can see, the pins I'm currently using are quite badly worn where they bear in the bushes.  The engine shop had a set of pistons and rods from a '30s MG or similar, which took 0.750" dia pins.  He "borrowed" a piston pin and fitted it to one of my pistons, and it was almost size-for-size.  Good.  My piston pin bores are in good order.  Most of the play in the small end of the conrod went away with an unworn 0.750" pin.

Second piece of advice: Try to find a set of new piston pins.  Rebushing the rods only makes sense if new piston pins are being fitted.

I called JP Pistons, and sure enough, they sell grey motor piston pins loose, but want me to confirm the length of my piston pins first.

The instructions from the engine shop are: Buy the JP piston pins, bring them, the rods and pistons back into the shop.  They'll fit everything up and rebush the conrods if needed. (R&R bush, ream and hone to size is about $70.)

It'll cost a few dollars, but I figure it's insurance against assembling the motor only to find that the gudgeons are noisy.

Rob

[Errol62]

Good stuff 👍


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[Errol62]

I dare say you guys may have seen this offering on eBay.
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com.au%2Fulk%2Fitm%2F162512986538
You probably don’t want to go out to 3.125 Rob, and the gudgeons are undersized I think at 0.750”. Ever heard of Nason pistons? I’ve bought brake hoses from this mob and been happy with them.


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[my8thholden]

way to go Rob ..you have done your checks ,assembled the facts ,made the correct decision ,get the right result ,well done ..I note your shop has new little end bushes also ..well done Vern .which engine shop do you use ?

[ardiesse]

Vern,

KC's at Castle Hill.  Kevin Carter sold the business a while back, but used to work there a day a week until last year.  He was my "go-to" person for anything grey-motor-related.  But Jack is a safe pair of hands.

Clay - Jack gave me a list of suppliers for engine parts.  JP pistons was first, and Nason second.

Rob

[my8thholden]

well there you go,I go to Jack at KC's also ..he did the head on my motor rebuild..

[ardiesse]

Clay,

I just clicked on the ebay link for the Nason pistons.  There wouldn't be any problem about the J-block taking 3-1/8" bores (although boring the block again will be a last-resort measure).  But I notice that the Nason 3-1/8" pistons take 5/64" compression rings.  Which is the same thickness as red motor rings, so Nason have made these pistons to take the same rings as the 138 red motor.  Compression rings for OEM grey motor pistons are 3/32" thick, by the way.

Rob

[Errol62]

Uh huh....

149(.6)cui grey, nearly 10% increase in capacity over 138.


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[ardiesse]

Umm, 3.125" bore x 3.125" stroke x 6 cylinders is 144 cubes, I thought.

(pi x bore squared/4 x stroke x 6 cylinders = 143.

A 3-3/16"-bore grey is a 149.

Rob