To bypass or not to bypass...
 

I am wrapping up the bottom end on my 489, and I am undecided on whether to install a 30 lb bypass in the oil filter pad on the block (Gen VI), or to block it off altogether as some have done. I have seen all the arguments for and against doing this, and for the most part I like the idea of making sure ALL of the oil hits the filter before it gets to the bearings. My one limiting factor is that I am using a thermostatic sandwich adapter that mounts the filter low on the block in the stock location, and clearance is kind of tight in this area. Not much room for a big filter here. I plan on running a Melling 10778C pump and 15W40 oil.

Anyone have an opinion on this?

Hmmm, almost 100 views, and no one has an opinion on this? :whistle:

No problem. I think I am going to go ahead and install a 30 lb bypass, since I am limited on filter size due to the location. Probably splitting hairs either way.

I have always blocked them off, and will continue to block them off. I don't want the risk of uncooled, unfiltered oil making it's way into the engine.
Eddie

Thanks Eddie. Are you using a 20 mm freeze plug and staking it, or tapping it and using a pipe plug?

No, the 20mm was a little to loose. I'm using a 13/16 plug that I turn down the height in the lathe. I couldn't find one short enough, so I just make it shorter. I use to just tap it for 1/2" NPT. It worked great, but it's a pain and it eats up taps. Most pipe taps are not made for cast iron, especially cast iron with a high nickel content. The hole is the perfect size to tap, but you have to be sure to tap it all the way to the bottom so that the plug screws in far enough. If not, it will stick up a little past flush and could hold up the filter adapter from sealing.

I do stake them just a little bit. But, I coat the plug in Loctite before I bang it in. The 13/16" is a tight fit. Between the tight fit and the Loctite, it's not going anywhere. The stake is a little extra insurance.
Eddie

You think the 20 mm might work with a liberal application of Loctite Red and staking it? I don't have access to a lathe myself and would have to hunt around for someone to turn a 13/16 plug down for me.

Thanks!

It wasn't that the 13/16" plug was to large, it was to deep. Your 20mm plug may be to deep as well. They are all offered in differing depths. I felt the 20 mm was to loose. Personally, I would be concerned running it. That's why I went to the 13/16". You don't have to turn it in a lathe if its to deep. You could always use a grinder, belt sander, etc.
Eddie

Something like this?

http://www.oreillyauto.com/site/c/de...0290&ppt=C0142

Tom, I do not know about using that style plug, have always threaded block way before assembly of engine and cleaning. You better go with Eddies, recommendation; if he has used both a expansion plug and pipe plug. If this thing is already together, I would be concerned with any small metal sliver, that could contaminate your oil galley.

Thanks Mark - yes, I think tapping it is out of the question at this point. Not really too keen on pulling the whole shortblock apart again to tap the thing. I have seen plenty of others on here who have it blocked with a freeze plug. (I think I recall reading about someone who pulled apart a shortblock that had it blocked with a coin!) I think using some Loctite and staking it should keep it from going anywhere. Not much more than that holding the factory bypass in place. I might give Eddie a call later this morning to see if he might have a part number and a source for the plugs he is using. The biggest pain might be finding someone to turn it down shorter for me in a lathe. Still trying to picture how you would hold onto something so thin to run it up against a belt sander to sand down the depth, but I don't pretend to be a machinist!

Just use you fingers to hold it. After a bit it'll stick to the melted flesh.

Just take a 1" paddle bit and drill a shallow hole in a board the depth you want the freeze plug to be and use that to hold the freeze plug against a belt sander.

MAIDEN, actually I figured I could just hold it in my teeth. :D

Ahhh, now THAT sounds like it just might work!

I just measured the plugs. The 20mm plug has a diameter of .800 and the 13/16" is .815. You can see that there is quite a bit of difference. It just so happens that the 13/16" plugs that I have are deeper than the 20mm. They are offered in different depths but my supplier only had these.

Here are a few pics of them side by side. The 20mm is on the right. I also attached a pic of one that is plugged with a 1/2" NPT pipe plug. That doesn't sound like an option for you if the shortblock is already assembled.

Send me your address and I will be glad to send you a plug. I'll cut it down first so all you will have to do is drive it in.
Eddie

Got your PM Budman. I cut a plug down today and have it ready to ship to you. I'll send it out tomorrow.

Let me know if you need anything else or if I can help in any way.
Eddie

Plug it! Just make sure to run a large high flow filter along with allowing oil temps to stabilize before WOT runs.

Ryan, I might be a little bit limited on filter size, due to the thermostatic sandwich adapter I will be running. Probably can't go any larger than a stock Merc filter.

This is the only thing I didn't do to my block. Hope it doesn't come back to haunt me.

cp, is yours a Gen V / VI? If it is a Mk IV, the bypass is in the filter adapter that mounts on the block. If it is Gen V/VI and you have not at least installed the 30 lb bypass in the block, then yes, you are definitely going to have problems and need to address it.

CP, if you havnt had problems yet I wouldnt stress too hard. How many hours have you run it since rebuild? People will call me crazy Im sure, but I have run Gen VI block right out of truck with just installing pipe plugs in factory oil cooler line ports and aftermarket remote filter adapter. The engine always had good oil pressure. Maybe I just got lucky. Even a blind squirrel gets a NUT every once in a while. Just be aware that you havnt done everything you could have to "bulletproof" the motor and act accordingly.......watch your guages and dont rev it to death

Dropped your plug in the mail today Budman. You should have it in a few days. Coming USPS.
Eddie

BYE, perhaps yours had the higher pressure bypass installed from the factory since it was running the external oil cooler.

CP is running a high performance engine with a supercharger. He definitely needs to have his bottom end oiling squared away, or he could end up with an expensive collection of parts in the bilge.

Eddie, I can't begin to thank you enough for going out of your way for me! I have heard nothing but great things said about you here on OSO, and here is another example why. Thanks again.

It was my pleasure. Glad I could help.

Eddie Young performance marine
Will you expand on the installation of the plug.
Im doing gen 6 zz502 right now. I just removed the bypass that is located off center. I was about to stake in a 30lbs but after reading some threads I think I wouldn't mind plugging it.

My engine is in my boat so I have limited space. I used my phone on reverse camera to remove the two bypasses. That part was eazy.