Titan 4.9L blowing mail seals

[ScienceguyXJ]

I've got a 4.9L Titan stroker and it's been blowing the front and rear main seals. Spare me any "should have stayed away from Titan..." It's been a great motor so far besides this problem. Anyways It's been doing it for about 1.5 years and I've replaced about 3 fronts and 3 rear main seals. Only has about 12k miles and is about 3 years old. Called and talked to Chuck with Titan about it a few times and he finally came up with the solution of trying some different seals. He recommended trying a double lip offset seal for the rear (Felpro BS40612) and a seal saver/speedy sleeve for the front. I just tried these new seals along with a new oil pan gasket and it lasted for all of a day until it started to leak again seemingly from the rear main and maybe one whole side of the oil pan gasket. I've had multiple shops install the seals and they are always good quality Felpro ones.

Titan built my motor with Chevy pistons that stick out of the bore and apparently can move around in the bore by grabbing on to the connecting rod making piston slap that I can hear from time to time. A guy in my home town who makes Jeep strokers claims that by using these Chevy pistons, and because they stick out of the bore so far, that it creates too much crank case pressure (from blow-by I assume) and causes the seals to blow. He recommended replacing the pistons with custom ones which could be around $4k when it's all said and done... I haven't been able to find anything in my research to support this claim and I've had a leak down test done on the motor which came out normal which to my understanding would mean that it's not having any blow by if I understand it right. Only other thing I can think of is maybe the oil pan, but it's been the same oil pan the whole time and it didn't start leaking until after 1.5 years. Or possibly since the pistons can move around in the bore it's wearing down the rings allowing blow-by but I don't understand how the leak down test would be normal...

Not trying to knock Titan, Chuck has been very helpful to me and he claims he has this same piston set up in his motor and doesn't have any problems with it. Has anyone else ever heard of this problem when using Chevy pistons in this application or has anyone else ran into similar issue with their Titain 4.9L? Cheers!

[racing89]

P.C.V. ?

[cruiser54]

How could it pressureize those 2 seals so much? The same area is vented to the valve cover. Any mods there?

[Cheromaniac]

Or possibly since the pistons can move around in the bore it's wearing down the rings allowing blow-by but I don't understand how the leak down test would be normal...

If compression (wet & dry) and leakdown tests are normal on all cylinders, the problem isn't blowby. If the crankcase is indeed overpressurizing, the cause could be something as simple as the rear valve cover CCV grommet or the pipe leading from there to the intake manifold being clogged up and not allowing the intake manifold vacuum to scavenge the crankcase.

[ScienceguyXJ]

Changed the "PCV" valve before on the valve cover before didn't make a difference. Blew out the seals again right after that. No mods to the valve cover. I'll check them again though and the pipe leading to the intake.

Haven't done a full compression test yet. May be the next step.

[SilverXJ]

The dipstick isn't blowing out of its tube?

It would be interesting to do a leak down at TDC and then at BDC and compare results. If the Chevy pistons are in fact rocking a bunch at BDC I would expect more leakage down there.

Also, are the slash marks on the rear crank seal surface still present?

[ScienceguyXJ]

Nah the dipstick never blew out of it's tube. I even propped it up for awhile so as to try and let any excess pressure dissipate through there but it didn't work.

Not sure about the slash marks.

[ScienceguyXJ]

I'll check with my buddy at the shop where I had to seals installed to see if he noticed the slash marks.

[ScienceguyXJ]

Not sure if we replaced one or both "PCV" valves on the valve cover and it's been over a year since we did. I'll try pulling off the rear one and see if it has a vacuum or not on it.

[SilverXJ]

I even propped it up for awhile so as to try and let any excess pressure dissipate through there but it didn't work.

Not sure if we replaced one or both "PCV" valves on the valve cover and it's been over a year since we did.

Since you pulled the dipstick out of its tube and the seals continued to have a problem I doubt it is excess crank case pressure. That or its such a great amount that the dipstick hole is too small to bleed it all off. This also would make the stock CCV system in effective. Again, I doubt that.

On the rear, the crank could be missing those slash marks, but I also don't know how necessary those are as some cranks don't even have them. This is the best pic I could find of them


Perhaps the block suffered from an excessive line bore, which would cause the seal not to sit correctly.

Then there is installation. On your 2001 your block had a rear main seal without the wings, so possibly the seal is installed in the wrong direction. The gap under the lip should be facing the engine. Also, RTV should be used on the main cap to keep oil from leaking out between the cap mating line. If the seal is installed dry w/o any lube that would kill the seal as well. Then there is always the possibility that the seal was damaged upon install. Are you sure it isn't coming from the pan gasket? Do you have the rear strap on the pan?

On the front seal the FSM calls for a special tool to be use to locate the timing cover while it is installed. Most people don't use this tool nor have it, but they never have a problem. Maybe your case is why that tool is called for. The tool slips over the crankshaft snugly and fits in the seal then the timing cover is bolted on. If you don't have this tool you can always modify an old balancer so it can be easily slipped on an off. And again if the seal isn't lubed or is installed backwards (I doubt that in this case) it won't work. Also, some RTV should be used at the end of the balancer between the crank and balancer to prevent oil from seeping out from behind the crank bolt.

[ScienceguyXJ]

Took off the fill cap and there is no build up of pressure, there is a vacuum there. Took off the front valve cover elbow and there is a slight vacuum there. Took off the rear elbow at the elbow and the intake and there was a vacuum on both. Neither of the elbows were clogged. There was some build up of engine grime under the back elbow on top of the head but nothing was clogged.

Seems like the next step is another leak down test and compression tests at TDC and BDC maybe wet and dry like you said SilverXJ...

[ScienceguyXJ]

I doubt it would be the bore Silver, because the problem didn't start until 1.5 years after assembly. Can't be the install either because I've had 4 different shops do the installs and they've all leaked and pretty sure all or most have used RTV too. I think it is something with too much crank case pressure that the PCV system can't handle the pressure. Question is are the pistons allowing too much blow by or is it just that the system can't handle it?

Not sure what the strap is you're talking about. Pretty sure it's always coming from the front and rear mains, accept for this last time after I did the seal saver and double lip rear seal because it seems to be coming out the rear now and the whole drivers side of the oil pan seal (which is new too). Not sure if anyone's used that tool you're talking about.

[SilverXJ]

There is a strap that goes on the rear of the pan between the last two bolts. U-shaped.

What I would do for an excess pressure check is remove the dipstick and replace it with a low pressure gauge with a suitably long hose. Tape the gauge to the window and take it for a drive. Watch the gauge.

[ScienceguyXJ]

Thanks I'll have to give that a shot, getting a lot of good ideas from NAXJA too.

[BADASYJ]

I seriously doubt your problem is from excessive crankcase pressure. If that were the case your fill cap would be the relief for the pressure as it really has no seal, your dipstick would also releive pressure before your seals blow.
I would b looking at the surface of the crank for any nics n burs. May have been caused by the first shop replacing seals using the wrong tool or just being careless. Also maybe your thrust bearing is wore and he crank is sliding back n forth eating up the seals.