Been having problems with my merlin 11 540 was hoping that someone has had similar issues.
I have bad oild leaks the bottom of the car is full of oil! Some of the plugs get oil in them. One of my friends said that the oil restrictor plugs in the rear of the block is the problem. My valve covers do not get any oil at all near the breathers and he said that if I have blow by that I should have some oil there and I do not. He says that on some of those blocks there were having problem with the restrictor plugs and it would pump a lot of oil up to the head and that is also why some of the plugs are fouling. He says that there are some new restrictor plugs that solve this issue.
He also told me to pull the valve covers and just crank the motor over and the oil should just flow out not spray out real hard. Need to do that and see what happens. One of his friends with a big chief head merlin 11 would put a drill on the pump shaft and would pump out the oil from the pan and loose pressure he said that it was the restritor plugs the problem.
Any one have a similar problem with merlling 11 blocks? Help please.
Sorry for the long post.

I don't have a direct answer for you, but until someone else who might have one for you chimes in on this, just for clarity, how long ago did you purchase this Merlin II block? I have a Merlin block, however I haven't fired it up yet. I know that the heads on it are called "Merlin III" and I believe the blocks are also "Merlin III" now also (correct me if I'm wrong on that, but meanwhile I'll take a look at my engine). I know that the earlier World cylinder heads were called "Merlin II", but the latest ones are "Merlin III", so I'm wondering if it's the same with the designation on their blocks too.

I've been running a Merlin II block for about 6 years now...no issues like that. You need to find out where the oil is coming from. Pressure wash it all off and find the leaks. They could be from anywhere.

No need for oil restrictors...I don't run any at all...no problems. You don't want to restrict oil to lifters for any kind of street use..even for solid rollers.


Give us some more info.


JIM

Bill it is a Merlin 11 I think that there are later version Like what you have a Merling 111. Hotrod you do not have oil restritors at all? I did not know that you can run with out them thought that you would pump a lot of oil to the top. You do not have leaks? What do you used for crankcase evacuation? I have to get to the botton of this. Next week end I will clean it up real good and just start it and let it idel in the lift to see if I can tell were it is coming from. What do you think about the plugs? Lot of oil up there would make then leak through and foul the plugs?
Thanks for your input.
Ps Something cool.
Last Friday night coming home from Tower shops a every Friday night car hang out here in Florida a guy pulled up in a Lamborghini Murciélago and was giving us the thums up and talking to us he was saying that he like the Chevelle how cool was that. My buddy was saying not to manny people get that from a guy in Lamborghini Murciélago.

I don't want to hear any of this. I am just about ready to fire my all new 540 up and hope I do not have oiling problems.
I have used an electric drill to prime the motor numerous times and it takes at least 5 minutes to get the oil comming out all the push rods. I do not run any restrictors.
I have the merlin 3 block.

There isn't much difference between a II and a III. I know they changed the main oil gallery to a *stepped* one like Dart does...can't remember..maybe they added steel caps?

Anyway, there is NO need for restrictors. The idea way back when was to limit oil to top and keep oil for mains and rods. That was with an oiling system that fed them all off the lifter feed galleries. Big blocks always had a slightly better setup with it down by oil pan rail. The Merlins use a true priority main system so that mains/rods get full oil pressure. The lifters get oil down the two galleries for them. First thing, most solid rollers are *edge orifice* design so that oil to the pushrods and rockers only comes from the area between the lifter and the lifter bore...not much oil is going to go up there in the big scheme of things. GM used edge orifice design on their *race* type flat tappet lifters too. Worked great for high rpm stuff....usually need the grooved rocker balls to make stock type rockers live with the limited oiling.

So the point of all of this is that your top end oiling is already limited a huge amount by design of the lifter. A hyd lifter is a little different and will put more up there usually. What do you have in it? Still shouldn't be an issue.

No cam mfg's recommend restrictors. You want 100% oil going down those lifter galleries. They are already starving for oil to some degree in operation trying to keep the rollers alive....sure don't want to cut them back any.

BTW- if you DO use restrictors in a Merlin block..please understand it takes a SPECIAL restrictor. You can't use a regular set for a regular big block. Merlin blocks take a special set. If you use the wrong one...well let's just say it ain't pretty!


I just use two breathers on my motor. One on each cover. Take a look at the oil drainback path from valvecover area. I've seen some headgaskets overhang the drainback hole in heads and restrict oil from draining back to pan. My motor pump a lot of oil up there and it makes valvesprings last a long time. The more the better! But it has to be able to drain back to pan.

If you have some other issue and you have a lot of blowby....you have other issues. Try to narrow down if you just have a bad oil leak or a real internal motor problem. Plug fouling can be from many reasons. Do they all foul or just a few?


So what type of cam do you have? What do you have for breathers? What kind of RPM? What heads? Maybe you need to do a leakdown test to check it's health.


JIM

I agree with Jim. My 540 is a Merlin 2 block and I have no problems like you described. Also I think that the oil restrictor is not a good idea on any roller motor. It seems to be an old idea that has slowly died off.

There was some subtle changes to the The Merlin III blocks over the II's. The early blocks, the II's, were missing all the inner head bolt holes below the intake in the lifter area. This was similar to the early Bowties from Chevy.

I'm not sure if Bill ever cast them into any of the later II's, before the III's were started in production, but they weren't in the first batches.

Chevy added these on the their later Bowtie castings too. They are really
required on certain engines to seal the head gaskets.

Harry P. Hunter

My 509 leaks oil out the front of the oil oan bad and runs like hammered crap hope you have better luck than me, my Merlin is a piece of sh--.

Sid

That's right...I forgot about the added head bolt bosses. My II doesn't have them.

JIM

My 509 leaks oil out the front of the oil oan bad and runs like hammered crap hope you have better luck than me, my Merlin is a piece of sh--.

SidI believe that oil leaks like you've described can sometimes be due to the absence of a PCV valve or due to an absence of another means of creating a vacuuum at the valve covers in order to relieve the crankcase pressure. Very often, the use of just a breather on each valve cover isn't enough, unless the vehicle is a trailer queen that only gets run 1320 feet at a time. I was getting oil leaks out of the back of my intake manifold on my SBC powered Vette, as long as I simply ran a breather on each valve cover instead of one of them having a PCV valve rigged up to the air cleaner or carb base via rubber hose.

But as soon as I hooked up the PCV valve, along with the breather on the opposite valve cover, I no longer had the oil leaking (once I replaced the gasket ofcourse). And as far as your 509 running badly, that may have to do with the carb if it was a rate engine thast you bought from World, because the carbs that World used to include with their crate engines gave a lot of people problems. World has since changed their carb choice. I would never be too quick to stick up for World since I've had my own problems with them too. But I'm just suggesting that there might be a simple explanation for your engine issues. I hope this helps.

I have a Merlin II 540 and it has the head bolt bosses. I have a Comp Cams solid roller with no problems. When I ordered the cam they said nothing had to be done to block. I also use a 6 quart pan. Only leaks I had were due to cheap-assed Chinese chrome valve covers.

I believe that oil leaks like you've described can sometimes be due to the absence of a PCV valve or due to an absence of another means of creating a vacuuum at the valve covers in order to relieve the crankcase pressure. Very often, the use of just a breather on each valve cover isn't enough, unless the vehicle is a trailer queen that only gets run 1320 feet at a time. I was getting oil leaks out of the back of my intake manifold on my SBC powered Vette, as long as I simply ran a breather on each valve cover instead of one of them having a PCV valve rigged up to the air cleaner or carb base via rubber hose.

But as soon as I hooked up the PCV valve, along with the breather on the opposite valve cover, I no longer had the oil leaking (once I replaced the gasket ofcourse). And as far as your 509 running badly, that may have to do with the carb if it was a rate engine thast you bought from World, because the carbs that World used to include with their crate engines gave a lot of people problems. World has since changed their carb choice. I would never be too quick to stick up for World since I've had my own problems with them too. But I'm just suggesting that there might be a simple explanation for your engine issues. I hope this helps.
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Ok,,,
I keep seeing this repeated so I finally just gotta ask :confused:
Where you guys are coming up with the idea a PCV does anything for oil leakage in a performance engine unless all you are doing is pokin around town?

What exactly does it do at anything other than idle or light load?
Or,,,, stated differently,, how does a PCV pull vacuum when there is none?

If you have a gasket leak it is a leak that needs fixing
A PCV has nothing to do with it.

And you never hook PCV to the air cleaner. :noway:
If you do all you have is a breather with a long hose


A performance engine needs breathers & the bigger the engine the more breather it needs unless you are running a vacuum pump,,, or a dry sump :D

I'm with you Mike....as I said...mine does fine with two breathers. No PCV...and I do lots of street miles.

I guess a PCV can't hurt anything in cruise light throttle conditions...but I sure like looking in and seeing my nice dry clean intake and ports. Don't need oil slime going through intake ports.


JIM

I have a merlinII block with a 14-71 Hi-Helix blower on it that actually builds pressure in the crank case and I have no oiling problems either. I also run no restrictors and build a steady 65-80 psi all day long. Any oil leaks I had were not the blocks fault, eg front geardrive cover, oil filter etc. I agree that you should clean the whole thing and get out the flashlight to do a good inspection to see where the oil is coming from.

Hope this helps
Corey

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Ok,,,
I keep seeing this repeated so I finally just gotta ask :confused:
Where you guys are coming up with the idea a PCV does anything for oil leakage in a performance engine unless all you are doing is pokin around town?

What exactly does it do at anything other than idle or light load?
Or,,,, stated differently,, how does a PCV pull vacuum when there is none?

If you have a gasket leak it is a leak that needs fixing
A PCV has nothing to do with it.

And you never hook PCV to the air cleaner. :noway:
If you do all you have is a breather with a long hose


A performance engine needs breathers & the bigger the engine the more breather it needs unless you are running a vacuum pump,,, or a dry sump :DAt WOT it probably won't matter like you've stated, but at part throttle positions (which is where you're at during MOST of your street driving) it will create a draw. Right or wrong? Do you dispute the fact that you need to have a little bit of vacuum to prevent pressure build-up from the crankcase? Why was it that as long as I had a breather on each of the valve covers on my old Vette that I had an oil leak spring out of the back side of the intake manifold? I repaired the leak, and it happened again. Then after I ripped off the manifold a third time to repair the leak again, I placed a PCV tube on one valve cover, and left one breather on the other valve cover ( kind of like the factory did back then) and I never sprung a leak again. Can you explain this? I did end up switching to a breather w/out the PCV valve which had a provision for a hose that I attached to the PCV port at the base of the carb.

Yes, I'm sure I was getting some slight contamination of the intake charge, but it beats having oil leaks, and the engine didn't smoke out of the tailpipes, and it still had great power. Don't vacuum pumps have to be cleaned out often? That wouldn't make them ideal for street use, for vehicles that considerable mileage is put on them, right? And I've heard of the one way check valves placed on header collectors getting damaged and clogged from the the effects of the heat. So that doesn't sound like a good idea for a true street engine either. So it seems to me that there are trade-offs here, and for real street vehicles, their isn't anything that's ideal, and w/out a trade-off.

At WOT the PCV valve doesn't do amything like you've stated, but at part throttle positions (which is where you're at during MOST of your street driving) it will create a draw. Right or wrong? Do you dispute the fact that you need to have a little bit of vacuum to prevent pressure build-up from the crankcase? Why was it that as long as I had a breather on each of the valve covers on my old Vette that I had an oil leak spring out of the back side of the intake manifold? I repaied the leak, and it happened again. Then after I ripped off the manifold a third time to repair the leak again, I placed a PCV tube on one valve cover, and left one breather on the other valve cover ( kind of like the factory did back then) and I never sprung a leak again. Can you explain this? I did end up switching to a breather w/out the PCV valve which had a provision for a hose that I attached to the PCV port at the base of the carb.

Yes, I'm sure I was getting some slight contamination of the intake charge, but it beats having oil leaks, and the engine didn't smoke out of the tailpipes, and it still had great power. Don't vacuum pumps have to be cleaned out often? That wouldn't make then ideal for street use, right? And I've heard of the one way check valves placed on header collectors getting damaged and clogged for the the effects of the heat. So that odesn't sound like a good idea for a true street engine either. So it seems to me that there are trade-offs here.
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Billy,
I ain't here to argue with you.
But yes I will dispute the "fact" that you need vacuum to prevent pressure build-up in the crankcase.

This is not why PCV's came about.
They came about so you would vent into the intake & burn the blowby instead of venting it to atmosphere.
Engines did just fine long before there was a PCV thank you.

I have built a couple of engines over the years & I can tell you that if you are building enough pressure in a damn small block to push gaskets out it had nothing what so ever to do with the PCV
I would be looking for the problems

If you stopped the leak it is because you fixed it correctly the last time or because you ended up with more venting, not because of the PCV

And I do have more than a few engines that do not have a PCV running around that don't seem to blow gaskets because of it,,,;)

I am not saying a PCV is a bad thing at all for a street driven deal,, just that it is not a cure all for leaking engines.

And by the way, when do you make the most pressure in the crankcase?
Here's a clue, it is not when you are cruising which is when your PCV is working ;)

No PCV here...just one breather on each valve cover.
Does just fine. :thumbsup:
Never could figure out why you would want to contaminate the intake charge with crankcase fumes. :confused:

Not trying to argue with ya Wolfman, just trying to figure this whole thing out, and all I can go by is what you and others say, and compare it to my own experience with street driven vehicles. So in light of our exchanges here in this thread, I want to ask you guys something else: about how many miles per week or per month do you put on your vehicles that you're only running valve cover breathers on? I drive all my high perf cars every single week from April thru October. Which includes some commutes to work through traffic. So I just want to make sure we're comparing apples to apples here.

BTW, I don't know what this is worth coming from World products, but my engine even came with instructions stating that I should atleast use valve cover breathers, but perferably a PCV valve. So why does it state this? I don't think that World is instructing their customers this because of emissions. And their written advice concerning this seems to line up with my own experience.

I'm not claiming to have all the answers here, and I appreciate the experience with engines that you guys have. But I also want to make sure that your experience and examples that you've offered have to do with engines used in vehicles that are driven considerbly more than merely 1320 feet at a time, and considerably more than just once or twice per month for a 5 mile commute to a local show or cruise night. Because my hi-perf vehicles always get used a whole lot more than just that.

Billy....

I understand your thoughts. As I said.....a PCV won't hurt anything and if designed properly can ease low speed oil issues maybe. They weren't designed to stop oil leaks..they were purely an emission issue that just happened to help with smelly oil fumes coming out from around a hot running engine. Made it a little nicer before we all had A/C on everything.

Often folks don't set them up as the OEM did. You don't want to really have PCV and breather on same valve cover. The idea is to draw through the motor. A PCV is a controlled vacuum leak....so you need to allow for it in the tune during cruise modes. Might even help a rich running combo.

But it is going to introduce oil vapors into the intake tract.....probably not a big deal..but it is just not what I really want in mine if I don't have to.

My car has driven numerous two thousand mile road trips with the 540 in it. I don't drive it everyday..but I also travel every week, so I'm in rental cars a lot! But a normal cruise night for me can be 200 miles easily. Plus I will drive it occasionally to work...about a 100 mile round trip. Just about any time I get in it, it's a 50-100 mile drive.

So anyway, a couple of breathers on a motor without excessive blowby is just fine. The more cubes...the more breather size you might need. If you want to throw a PCV on it...it's no big deal...but I wouldn't expect it to really change much. If it's leaking...there's something wrong and a PCV won't fix it. If there is so much crankcase pressure at low speeds that a PCV operates at...then there are definitely other issues.

JIM

FWIW, below is a pic of the Moroso breather that I found to work the best on my old Vette when I had it. They are made to have a hose connected to them coming from the carb base port. There isn't any PCV valve inside of them. Only a filter. As long as I had one of these on one of the valve covers, along with a standard type breather on the other valve cover, the engine didn't leak any oil out of the gaskets.( Summit Racing part# MOR-68780)

Thanks for your reply Jim. I'll consider what you've said. I hope that I didn't derail nor hijack this thread.