Nathan Faunce

great info dj thank you, fortunatly i was able to locate the casting number where you said, it is a 7120 casting head, could I still potentially have a vacuum leak with the 7120 head on the engine with the 2000 intake manifold?

djgrayxj

Note from DJ
I don’t think so; but you might go to a parts store and ask if they have an intake manifold for the 1991-95 Jeep 4.0L and one for the 2000-01 Jeep 4.0L. If they do ask if there is any possibility you can do a comparison by laying one on top of the other and have a look for yourself.

Nathan Faunce

I don't believe it does have a leak. I disabled the fuel pump and had my buddies crank while spraying the manifold and gasket with starting fluid it didn't try to catch and start up so It should be just fine

CoffeeCommando

If you have a manifold leak you will hear it. It's either going to be a hiss (intake) or exhaust leak.

Nathan Faunce

there's no leaks, I double checked everything and retorqued to cover my ***

CoffeeCommando

Why did you start looking for vacuum leaks? I missed that part. That won't stop you from starting no matter how bad it is.

Did you ever do a compression test on that engine? I would.

What length are your push rods and how did you set the valve lash? Was your block decked or is it completely OEM? Which headgasket are you using?

Nathan Faunce

well I decided to do a leak down on the cylinders last night just to verify everything was fine, and I got screwed by titan. #1,#4 both leak out of the Intake and exhaust with the cylinder on tdc compression stroke, i got literally 80 miles put of their cylinder head before it junking, not 100% sure exactly what happened but I'm pretty sure the valves burnt up or the machined the seats incorrectly, I'll be pulling the head off on Friday I'll post picture of the damage then, can't decide if I want to take the head to a good machine shop and have them go through it or buy a good cylinder head that won't screw me like titans, any suggestions?

CoffeeCommando

Find a good machine shop is the only answer. You can try to call Titan and express your extreme dissatisfation. Tell them you'll be publishing the results in the Cherokee communities and that you have already met several others that have been burned by them several times and that it isn't a wiped cam lobe or mis-installation on any of their parts, it was always Titan tom-foolery. Think about it and get good and agitated before you give them a call, but have all of your data and results and what you're going to say well planned and thought out. They're going to say you screwed something up. They'll try to offer you a discount, don't take it. They're pulling a secondary profit off of you. Tell them they're fixing it on their own time, shipping included.

Then, when that fails, FIND A GOOD MACHINE SHOP. Don't simply look at the biggest fanciest places. Avoid them. They depend on looking like a bunch of pros to get people to come to them. The machinist I go to know has done it his whole life and it's a run down place with old cars and engine parts everywhere. That guy knows a lot and he showed me what's wrong with (my already working) head and how he does his work. He had a 4.0 head in the area and showed me the differences. When I asked questions he gave informative responses that taught me the things I didn't understand or know.

Ask them to find out what spring pressures are currently on there, and what they would recommend. Bring what they tell you back here and I'll give you some feedback. #1, they shouldn't give you a point blank answer. They should ask you what you're going for and why. Actually, tell them you want to go with a higher lift cam, and ask them what they would do for a head that was going to go that route (that's actually the route I would avoid, but their input will tell you what they know and if they're just trying to make money off of you).

Stroked 4.0's are NOTORIOUS for wiping cams and lifters out. If they don't make mention of it... it's not a good sign. They should also make mention of what types of oil and additive you should be using, and ask you what you used during the break in.

Excessive spring pressures and lack of zinc (ZDDP) in oil is a quick combination for killing a stroked cam lobe. You also need to get new push rods and the only way to do that is to measure them. If you didn't do that in your build you're asking for a premature break down as well. You can't crunch numbers and think you can pre-order the right stuff, it just doesn't work. You have to measure them all, individually, to make sure you get the right length. You can get push rod checkers that come in adjustable lengths. You have to do this in order to get things right if you want your engine to last.

Also, You never mentioned your valve lash adjustment procedures. If you don't do that right you will leak pressure as well. Before you even get on the phone with Titan you better have known you did that correct first. If you didn't, do it, THEN do your tests.

Them having touched the head means they might have true decked it. That changes your valvetrain geometry numbers (a little, not much to be dangerous... but we are dealing with Titan so who knows what the $10 an hour mechanic did back there). Changing your head gasket thickness also changes that equation, and if you had the block decked that also changes the equation. You need to know all these numbers, because stone-face over there will vet you out with these questions to get a feel for how much of a noob you are so he can put you in your place. Trust me on that. It's like dealing with defense attorneys that build engines.

Nathan Faunce

alright guys so I got it all figured out, removed the head and it actually is not titans issue, after some deep digging on my issues I found out from jeep that 4.0 factory rockers are only good for .450 lift anything more and they start to bind up creating resistance in the engine and overloading your pushrods and lifters, I popped 3 lifters and bend the pushrod on #5 exhaust, I verified the .450 lift aspect from assembling my rockers on the head while it was on my bench and checking my range with my dial indicator, as I was told .450 is all it will go, so future reference the comp cam xtreme 4x4 can is a .472 and .46- lift camshaft which is too much for the stock rockers, the comp cam lifters can handle the higher strength valve springs with no issue but you create a weak spot in your pushrod and rockers, I got should of 505 performance and got a set of performance rockers a set of chromoly pushrod and a valve cover spacer (rockers wont clear valve cover with the lift my camshaft has) I went through the head and lapped all my valves just to make sure I will have no issues with my valves sealing and the rest of my parts will be here tomorrow so I should have an update on how it all turned out Saturdayish, thought I would share my findings although I'm sure someone else on here has a post with the same info somewhere.

CoffeeCommando

I'd avoid high lift. Yeah, the cam won't wipe out immediately if you do everything right. More lift means more spring pressure, means more resistance and faster wear.

If I was driving a high lift 4.0 I'd be using Joe Gibbs Race oil AND putting in a bottle of Lucas TB Zinc Plus every oil change, every 3k miles like clock work. I would avoid synthetics, unless it's Joe Gibbs has a good formula for not interfering with ZDDP in high seat pressure applications.

I just ordered some samarian cobalt magnets and I am putting them in strategic spots away from rotating assemblies when they come in this week. I would do the same if I was you. I spent $55 and it's well spent for wiped-cam metal catching insurance. Not only that, any and all metal, no matter how small the micron (meaning everything that comes near it that is too small for the oil filter), will be caught and kept from circulating. Most engines are slowly degrading over time wearing out because of the particles the oil filter can't catch. The more it wears out the more the stuff is residually in the engine after each oil change. The more the engine wears, the faster it will wear.

There was a recall on Hyundai Sonatas because of left over metal in the engines. I wonder how many engines straight from the factory have that or are walking the line of of the maximum allowed limits.

Nathan Faunce

the magnets aren't a bad deal at all I may have to look into a few, the high lift does add more pressure and higher ware to everything if it is not done correctly I agree, however since I'm not running extremely hard seats upgraded stainless valves 107# springs hardened valve retainers and keepers, chromoly tubes roller rockers and comp cam lifters with the comp cam, the comp cam performance timing set and a high flow oil pump, and I'm religious about adding zinc additive with oil changes since it is a flat tappet engine i would imagine longevity shouldn't be that much of a concern, however the oil you mentioned may be something worth looking into, but I'm also very religious about synthetic in everything (except for during engine break in) as it has better flow patterns and deals with heat and stress better I've found at least although I'm sure that could be a huge debate haha, but I think the magnet thing is definitely something worth looking into however I would almost be leary of trusting it to stay by itself without a little epoxy or something, but that could just be me being paranoid about having loose components in a crankcase

CoffeeCommando

If any company has an oil with synthetics designed to give the synthetic abilities and also not interfered with ZDDP it's going to be Brad Penn & Joe Gibbs (of the two names I am most aware of). AMSoil makes good oil, but I don't know how developed they are in that particular area.

You don't have to worry about magnets coming loose when it's a rare earth metal. Ceramics lose their magnetism over time but rare earth magnets seem to hold it from my speaking with K&J Magnetics. Ceramics (the ones that easily chip) start to lose it after (I want to say) 3-5 years. Samarium cobalt magnets hold their magnetic strength up to 302, then it starts to taper off. The currie temp (the temp that completely and permanently removes the magnetism) is 644. If it heats up to 302 and beyond the magnetism tapers off, and when the temperature reduces it tapers up.

I still recommend taking the oil pan off at least once a year to check them out, so put them in the down face position near to each cam lobe (that's what's going to wear more than anything else). I'm also going to put one near the oil pump sump. I will still put 4 bars on the oil pump body itself as well. I'm probably going to make some sort of wrap around sleeve for it.

CoffeeCommando

I just did some more investigatin' into the oils since I wasn't sure which oil I was going to run after my first 500 miles on the new cam. I have solidified my choice with the HR Driven 10W-30 from Joe Gibbs. It's a synthetic that has a high ZDDP blend, so you get the extra heat/thermal protection of a synthetic that will last longer as well as enough ZDDP to preserve the tappets of a cam for a hot rod muscle car designed to have higher lift and higher valve spring pressures. That should do excellent for a stroker (and any 4.0 since it falls under the "Classic" category) application. The 4.0 is a late 80's era engine so as of 2007~ it was technically a classic. It uses classic valve train technology, and the 4.2 that came before it was in use since the 60's. It was the same engine with some crank and head volume differences, with a carburetor. It's still the same valvetrain that was used in the 4.2 since the 60's so as far as oils go, a hot rod/classic engine oil is what we should all be running.

http://www.drivenracingoil.com/dro/h...c-10w-258html/

In the words of Lake Speed Jr. from Driven, if it has the API logo on it, it's not a race oil, and you also don't want to use it on a classic car. Everything you can get at the stores regardless of what it says is going to be API only. Looks like I am buying all my oil from the internet or from independent dealers from now on.