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Rear Crank Seal - Replace With Engine In Place?

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smdl Gold Member Shaun Laughy
Courtenay, BC, Canada   CAN
Hi, folks.

I'm enjoying continuing to get to know my (new-to-me) TR4A, and am currently working on addressing a significant oil leak. Initial investigation appears to indicate that the rear crank seal is the culprit, which seems to be a very common issue based upon what I see when searching the forum. So, I have decided to address the problem by installing a Mad Marx Viton seal kit. While that is on order, I am now looking into the process required to do the work, and I have a couple of questions that I haven't yet been able to find answers for in my searches (at least not yet).

1. As I have recently been fortunate enough to purchase a second-hand 4-post lift, I can have very good access to the bottom of the car, and wonder if it is practical to do the seal from the bottom with the gearbox out. I need to pull the gearbox anyway, so it might be nice to just do the seal that way rather than removing the engine, as well. That said, if the chances of success are lower when doing the work that way, I'd rather not take the risk.

2. I have seen repeated mention of soaking the felt material in "Permatex" before packing it in, but I'm not sure what specific type of Permatex is correct. They make so many different products that I want to make sure I use the right one.

I'm sure I'll have a few more questions as I progress through the repair, but that's all I can think of at the moment. Thanks in advance for any shared expertise!

Cheers,
Shaun

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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
It can be done in the car; but is a lot of hassle. Whole lot easier to R&R the crankshaft with the engine upside down, so you can lower it onto the upper bearing halves rather than trying to hold it with one hand while you install the caps with the other hand.

You might also want to look into the condition of the rings, etc. Worn engines produce more blow-by; which can overwhelm the PCV system and pressurize the crankcase. IOW, you probably need new rings (or a whole liner set) along with that new rear seal.

I use Permatex "Aviation Form-A-Gasket #3" https://www.permatex.com/products/gasketing/gasket-sealants/permatex-aviation-form-a-gasket-no-3-sealant-liquid/

But my guess is that any gasket shellac (eg Indian Head or Gasgacinch) would work just as well. Note that, when you're doing it right, the sealant should ooze out from the joint between the cap & block (showing that the seam is full of it as well as the cavity with the felt packing).



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

smdl Gold Member Shaun Laughy
Courtenay, BC, Canada   CAN
Thanks, Randall. I can see why it would be more practical to have the engine upside down, so will go that way.

With regard to blow-by, I can see that the previous owner suspected as much, as he has messed with the breather setup a bit. That said, the engine runs great, and I have checked compression, finding 154,153,154,153. With those numbers, is it likely that there is a problem of this nature? I'll bite the bullet and do a full rebuild if necessary, but would naturally prefer not to if not required. Anything else I should check to validate of crankcase pressure and ventilation are what they should be?

While I have the engine out, I suppose it makes sense to check axial play of the crank, as well as main and rod bearings. I can see this little job growing by the minute. Anything else I should look at while I'm in the bottom end?

AllI wanted to do was enjoy the car for a season before getting into it deeply, but it certainly won't be the first time that my optimistic plans have been foiled. smiling smiley

Cheers,
Shaun

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malbaby Avatar
malbaby malcolm baker
kyabram, Australia   AUS
The question is how far do you want to go in rebuilding the engine.
If you have some spare cash, I would do the full monti including balancing of all moveable parts of the engine and clutch....also lighten flywheel.
Delete the tractor style {cooling?} fan and replace with harmonic balancer conversion and thermo fan.
Have the camshaft reground... check all bearings.etc.etc.

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
Of course, the other alternative is to just let it leak and enjoy the season. Oil is cheap, so is kitty litter (for your parking spot).

I've never had a TR leak worse than about a quart every 2500 miles or so, even when the cylinder walls were in really bad shape. OTOH, my Buick wagon was leaking about a quart every 250, and I drove it some 3000 miles that way. Costco had a 3 gallon box of Delo 400 (which is a decent oil, if not my first choice) for under $40. (Leak caused by incompetent mechanic in DeKalb, IL; long story. It's fixed now.)



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

smdl Gold Member Shaun Laughy
Courtenay, BC, Canada   CAN
Well, the car lost about 3/4 of a quart over about 60 miles, so the leak is pretty substantial. I don't think I want to leave it like that for a season. So, I suppose I'll take the engine out to fix the leak, and will probably take the opportunity to check overall condition while it's out. Easy enough to check the bottom end with the crank out, and I might as well pop the head off while there. If everything looks good, I'll just be out some gaskets, I suppose.

Is there anything reasonable that can be done to improve crankcase breathing?

Thanks again.
Shaun

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
In reply to # 1493929 by smdl Well, the car lost about 3/4 of a quart over about 60 miles,
Wow! That's impressive! You must be leaving a trail to find your way home!

I'd double-check that the PCV valve is actually flowing vacuum; there are service instructions at https://drive.google.com/open?id=0B2H2NJt34OffYmIyM2Q5ZGQtY2YyMi00ZmVkLThiYWEtZTE3MTUyZDEyMDM0

Some folks have gone as far as removing the plug on the LH side of the engine block, and fitting the road draft tube from a TR3 or early TR4. I haven't tried that, but a friend got significant improvement on his TR6 by disconnecting and plugging the factory PCV line, and just adding a length of heater hose to the port on the rocker cover. The other end was left open, hanging down near the ground. The intention was just to keep from producing clouds of blue smoke, but his oil consumption also went down noticeably.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

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Geko Avatar
Geko Stef SG
Kuala Lumpur, WP, Malaysia   MYS
In reply to # 1493929 by smdl Well, the car lost about 3/4 of a quart over about 60 miles, so the leak is pretty substantial. I don't think I want to leave it like that for a season. So, I suppose I'll take the engine out to fix the leak, and will probably take the opportunity to check overall condition while it's out. Easy enough to check the bottom end with the crank out, and I might as well pop the head off while there. If everything looks good, I'll just be out some gaskets, I suppose.

Is there anything reasonable that can be done to improve crankcase breathing?

Thanks again.
Shaun

There's more than a rear crank seal leak IMO, so engine out is a wise decision. Re crankcase breathing you may take the opportunity that the engine is out to fit the early TR4 snorkel breather or make your own. Also have the original TR4A vented oil filler cap. Remove the PCV and fit a draft tube going down the chassis and you're away.

smdl Gold Member Shaun Laughy
Courtenay, BC, Canada   CAN
Thanks, gents.

Will have a look at the manual and at the link provided to see if I can determine the functionality of the PCV system. Trouble is, the previous owner had made some changes, likely to see if he could determine if crankcase pressure was a factor in the leak. So, I'm not really sure how it should be configured yet. I have attached a couple of pictures showing what is there (and is obviously not as original). As you can see, one of the hoses is loose with a domestic air cleaner type filter, and the outlet on the valve cover is currently plugged. The oil filler cap is vented, so perhaps that is the earlier type? Any additional information would be greatly appreciated. I'm picking up the lift tomorrow, but hope to have some time to dig into this over the weekend.

Cheers,
Shaun

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Britnut Randy DeRuiter
Nacogdoches, Texas, USA   USA
Definitely not stock there! Where does the other end of the hose attach? If it goes close to the fuel pump on the other side the previous owner likely opened up the plug on the lower part of the engine block and attached a hose fitting there - that is where the road draft tube would go on earlier engines.

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
This is a bit outside my area, but I believe some (later?) TR4A did come with that style of (vented) cap. However, the vent is intended only to allow a small amount of fresh air to be sucked into the crankcase; it's not large enough (nor intended to be) to vent the crankcase fumes. The port you have capped off should lead to the PCV valve; then the other side of the valve to the intake manifold.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild


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Plate  F Crankcase breather raw.jpg

smdl Gold Member Shaun Laughy
Courtenay, BC, Canada   CAN
In reply to # 1494099 by Britnut Definitely not stock there! Where does the other end of the hose attach? If it goes close to the fuel pump on the other side the previous owner likely opened up the plug on the lower part of the engine block and attached a hose fitting there - that is where the road draft tube would go on earlier engines.

Hi, Randy.

The makeshift filter connects to a steel pipe that passes behind the head. You can actually see it in the background of the picture, just to the left of the fuel line in the image. I'm not sure where that comes from on the other side of the engine, but will look.

Thanks,
Shaun

smdl Gold Member Shaun Laughy
Courtenay, BC, Canada   CAN
In reply to # 1494101 by TR3driver This is a bit outside my area, but I believe some (later?) TR4A did come with that style of (vented) cap. However, the vent is intended only to allow a small amount of fresh air to be sucked into the crankcase; it's not large enough (nor intended to be) to vent the crankcase fumes. The port you have capped off should lead to the PCV valve; then the other side of the valve to the intake manifold.

Thanks, Randall. Will have a look to see if I received the PCV in the parts stash that came from the engine.

Cheers,
Shaun

ducbsa Bruce Metcalf
Berryville, Virginia, USA   USA
In reply to # 1494101 by TR3driver This is a bit outside my area, but I believe some (later?) TR4A did come with that style of (vented) cap. However, the vent is intended only to allow a small amount of fresh air to be sucked into the crankcase; it's not large enough (nor intended to be) to vent the crankcase fumes. The port you have capped off should lead to the PCV valve; then the other side of the valve to the intake manifold.

The device is a one way valve that allows air and fumes from the valve cover area to be sucked into the intake manifold to be burned in the combustion chamber, not the reverse.

Geko Avatar
Geko Stef SG
Kuala Lumpur, WP, Malaysia   MYS
Based on your pic, I bet this engine isn't vented at all. First thing to do is removing the plug on the rocker cover and replace it with a draft tube open to atmosphere. Your oil leaks will drop dramatically.

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