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!

 

[xjtrailrider]

My guess would be that the crank is the issue, not the pistons.

 

[D.I.T.A]

It sounds like excessive crank case pressure like your buddy was talking about , we deal with the same crap with anything making big power here at our shop simply the stock pcv system can't handle the volume of gasses in the case and it finds another way out aka blowing seals. check your pcv system for any problems or you might have to run a catch can running both valve cover hoses to it.

 

[ScienceguyXJ]

Thanks guys, yeah I'm leaning towards it not being the pistons too. I'll have to research the catch can idea more.

 

[ScienceguyXJ]

It's just odd... where would the excess pressure be coming from if not from too much blow by?

 

[ScienceguyXJ]

DITA, would the catch can just act as a filter to prevent the system from clogging?

 

[CobraMarty]

Take the fill cap off, Do you feel air/pressure building up when you put your hand over the opening?

 

[techno1154]

Thanks guys, yeah I'm leaning towards it not being the pistons too. I'll have to research the catch can idea more.

I like the way you think,...positive.

Think about this,...The number of bored and stroked engines out there. How of them keep blowing out oil seals? Well, if you turn insanely high RPM with that 4.9L engine then you could get plenty of compression passing by the pistons going down to the bottom of the engine . At the low RPM that one would normally turn an engine in an XJ it should not be that bad.

Like someone else said before me, go over all the vent tubes coming off the valve cover. They could be your problem.

 

[O-Gauge Steamer]

ScienceguyXJ,
If you would like, I can show you the "catch can" I installed on my Heep. It is a Moroso oil separator.

Shoot a PM...

 

[ScienceguyXJ]

Might as well stay positve techno, got so much invested into I want to make it work.

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...

I'll take you up on that O-gauge!

 

[markaboo929]

Easy cheap fix is crankcase evac set up...
http://www.summitracing.com/parts/vpe-1189/overview/

 

[RaVenCCorax]

believe it or not on certain engines this is fairly common. between blow by and the extra volume/rpm your massively over what the stock system can handle. if you have the ccv (renix) style system that was i believe an .049 hole. if that clogged it drowned the air filter in oil through back flow. make sure all your pcv hoses are clean and clear. replace pcv valve . i personally run a generic cj/chev/$2.99 common one hell most are same part number anymore. 3/8th id hose and a large air compressor coalescing filter.

coalescing filter or catch can same thing basically. gets the oil mist seperated and prevents nasty buildup in intake and engine. plus shows blow by and vapors. drain it once in a while. the pan evac system works great for open headers but once you install a cat and muffler it loses efficency due to backpressure in the system and can actually function in reverse.

some hard core racers go above the pan evac system and install vacuum pumps into the crankcase to lower pumping losses even more. use to be modded smog pumps but now actual pumps designed for it. instead of pcv valves they use vacuum relief valves. about 15 inches of vacuum was worth measurable power increase. but of course some guys went overboard and were actually wiping out engines. sucking oil out of bearings. destroying seals and having to reverse them to keep air from getting sucked through.

 

[RWKHausSupply]

I have a locally built 4.x higher compression (est at 10.5ish) stroker. It has been great. Doesnt run hot ever (could be the higher end cooling parts), and see's all RPM's regularly when in use.

I can NOT run a PCV system only! Can Not, with out having a consistent blow by caused oil leak, out of the rear main. I thought it was a bad rear main when I fist got it in and even built a custom oil guard that clamped to teh exh tube that runs under right where the oil drips down, and diverted it around the exh. I didnt want to catch fire.

Well I pulled the PCV valve out completely after about 3 or 4 runnings, with it dripping and found that without the PCV system that its all good.

SO now I run a breather, and a PCV and a breather back to the int tube. these three open sources are enough now.

I would say you likely just need a different crankcase breather and PCV system.

 

[Boostwerks.com]

Have you done a comp/leak down test? If those read good, I would simply upgrade the crankcase breather system as previously mentioned.

I'm running a similar open system with an oil separator and catch can on our turbo'd 4.0.

 

[ScienceguyXJ]

Nah, have only done a leak down test so far. Going to do another one and complete compression tests and if those check out all these suggestions seem great!

 

[cal]

I also run a high compression high RPM stroker (11.5:1, 6500 rpm) built by the same guy as Robert above (Russ Pottenger). Like Robert, I run a breather on the valve cover to get rid of main seal leaks.

It did work, too.

 

[ScienceguyXJ]

Mine isn't too high of compression, supposedly around 10:1 or just under. Def higher than stock though.

 

[ScienceguyXJ]

Mine doensn't run hot either. Maybe a few degrees higher than stock but right around 210. New radiator on it. Might throw a 180 degree thermo on it eventually.

 

[ScienceguyXJ]

RWKHausSupply and cal, mind sending me a pic or can you tell me where you bought your breathers/ modified PCV sytems from? Or did you have to custom fab them? Thanks!! Think I'm getting closer finally.

 

[ScienceguyXJ]

A big thanks to O-Gauge Steamer! I think we may have figured out a solution to the problem. Made a new vacuum port in the throttle body spacer to produce a higher vacuum in the PCV system and installed a Moroso air-oil separator in line with the rear PCV elbow on the valve cover. We sealed off the old vacuum location on the intake and now the PCV system gets it's vacuum from the air inlet on the throttle body spacer. This along with drilling out the opening on the rear elbow PCV increased the vacuum from 4 inches of mercury to 12, increasing the vacuum in the crank case by 300% and the idle is still fine with no engine codes.

Today we did a warm "dry" compression test on the motor and there was only a 7 psi difference between the highest and lowest reading which equated to a mere 3.8% difference and the average 180 psi equated to a 10:1 compression ratio which the motor was designed to have from Titan. Tried a "wet" run on one cylinder but there was no difference and didn't see any reason to do a full wet run since all cylinders were well within spec.

Going to monitor the seals now for any more leakage and maybe replace them one more time.

Does anyone see any benefit to still doing a leak down test?