BSE and High oil pressure (what about leaving shafts in?)

[turboglenn]

I am about to undergo another enine build, this will just be a budget "piece together" of parts i already have, but i am wondering about what happens when you leave the front one in but with the belt missing?

This is how the motor that i just took out was done when i had to do a waterpump or something one day and felt like doing a "ghetto BSE" and cut the belt off and just uses the stub shaft from the mirage for the rear one. I never hooked an actual gauge to it to see the pressure, but after 5 years of life i guess it had to have been alright to come out in as good a shape as it did! IT bent a rod and every bearing in the motor was beautifull, PLus my turbo ran on it fed from the head for at least 5 years and it's a garrett journal bearing unit.


So for the next budget build i'm working on (using all parts i already have) do i use the block with the fron shaft still in or is there harm in doing that?

My other option for this build is wether to use a factory turbo or N/T block (difference being squirters) and the shaft option goes for both... DO N/T blocks have lower pressure reliefe valves by chance????

 

[mobythevan]

Interesting that you bring this up right now, because I was out looking the last couple days at turbo vs non turbo oil housing and relief holes. Everything looks identical to me in the oil housings. However, up on the head at the end of the oil runs from the lifters is the "oil body" and it is different between NT and turbo heads. It is the piece with the 3 bolts holding it on. On a NT engine it is tall, on a turbo it is almost flat. Is this what changes the oil flow/pressure for a non turbo engine since the squirters are missing? I disassembled both oil bodies and the NT one does look like it would allow more oil flow, I dunno. Maybe it has nothing to do with oil flow overall.

 

[turboglenn]

Is there any one else that might have some input on the pressure with the front shaft still in and only the back one removed?

Ii was mentioned to me the possibility of turning them down on my lathe to where they are round and won't have any effect while retaining the system. But, there's still a lot of rotational mass there and there would still be the belt to deal with, so i think i'm going to scratch tht idea

I'm anxious to start measuring oil pressure at the head on some cars, but the weather has been burr fricking cold out and i've only been able to manage an oil change and some other misc stuff.

 

[toofast82]

I would think with the front shaft out and blockoff bearings installed with no oil squirters. You would probably have some pretty damn high oil pressure. I would think if you left the front shaft installed it would have slightly lower op than with the blockoff bearings installed. As far as #s, ?

 

[turboglenn]

Well, i got some good news to report. It seems that the N/T OFH's relief valve does have a lighter tension spring ( it's noticeable when i grab them and squeeze them one right after another. In fact to test that it wasn't insanity, I threw them in the tool box and was able to pick the NT one just by spring pressure. Other than that they look alike, same number of coils, coil diameter is identical... So i can't figure out how they made it lighter tension ( or if mine's just worn WAY out) But, i'm going to try and put it in my OFH next time i'm under the car!

I'll have to hook an oil pressure gauge up to see what's happening but it wil be worth the time and mess if it ends up putting the pressure in the desired zone after the swap.. If that doesn't work then I have another OFH that's ported more than any other one i've ever seen on the net when searching, I'll try and put a pic up later.

I was also wondering if anyone knew of any differences between an N/T and turbo oil pump nad front cover assembly that might keep ressure down? There has to be something because if the NT block had the oil pressure of a turbo block with no squirters and no balance shafts that thing would be pegging the gauge constantly... *scratches head*

 

[Boost92awd]

If your going to do a BSE, why wouldnt you just remove both shafts? Its less weight. I mean if your going to go and remove one shaft why not spend the extra 10 minutes and remove the other shaft. Then just spend the whole 5 minutes it takes to port the oil relief valve.

Its proven to work and gets rid of the most weight and rotating mass.

 

[turbosax2]

Is the spring maybe weaker just because it's older? Looking through CAPS I only see one part number for the spring, n/t and turbo are the same.

 

[turboglenn]

If your going to do a BSE, why wouldnt you just remove both shafts? Its less weight. I mean if your going to go and remove one shaft why not spend the extra 10 minutes and remove the other shaft. Then just spend the whole 5 minutes it takes to port the oil relief valve.

Its proven to work and gets rid of the most weight and rotating mass.

If you'd followed/read any of my other posts about my oil pressure and other's as well you would understand... The first time i left the front shaft in, the motor was in the car and there was not only too litle room to get it out, but then i had no way of blocking off the passages if i did get it out, so pulled the back one and cut the belt to the front one.

It was cold out and i had only started for a waterpump change that turned into a "ghetto BSE" just because i was in there anyway (that was over a year ago or so) Then in december 08, that motor got pulled for a bent rod due to a hydrolock.

The entire time i ran the motor that way (no rear shaft, front unhooked), i had no issues with high oil pressure what so ever. AS soon as i put the new motor in with a proper BSE, ported OFH ( and then a way over ported 2nd OFH ) i still had well over 100psi of oil pressure by 4k RPM (not good on lifters and turbo seals). With the 2nd ported OFH i got it down to 95psi by redline, i can deal with that because i put what turned out to be a kinda rare second oil relief valve in the head that keeps the pressure to the turbo and lifters in check no matter the bottom end pressure

As for the weight, with no belt it's no longer "rotating mass" which makes the few pounds that the front one weighs negligible (at least IMO). It's the rotating mass i'm concerned with. This is still a street car with stereo, subs, seats, spare tire etc.. so a few pounds of dead mass really don't bother me at all.

Is the spring maybe weaker just because it's older? Looking through CAPS I only see one part number for the spring, n/t and turbo are the same.

That's what i was thinking because i couldn't find seperate part #'s for it either. I wish i had a spring tension scale so i could really see the difference in them. I still may resort to either machining a new releif valve bolt that will put less preload on the spring or i may just clip a half a coil at a time from the stiffer spring until i get the pressure i desire.

Time and experiments will tell, now if the weather would stay over 30* for a day or two i might get out and actively put some of these theories to the test!

This 2nd engine i'm putting together is strictly for a backup if something were to happen to this one ( or better case, i find a light, small RWD shell and start on my RWD 4g63 vehicle )

Either way, i'll update as progress or theories arise, and will be taking comments, advice, thoughts and any other option into conideration for testing. I'm thinking about hooking this engine up on a "running stand" using an old OEM 2g ECU and a small fuel can with a stock pump in it, that way i can run it, test it, change things and run and test again without worrying about my DD car.

 

[Boost92awd]

Then in december 08, that motor got pulled for a bent rod due to a hydrolock.

Hence why I said why not just pull both of them out. Its easy enough when the motors out. I was talking about your current build, not your last set-up, sorry if I made it sound different.


Do you have any pictures of your ported OFH, I'd like to see just how much you did port them.

 

[Pirrofab]

I have heard some horror stories with the Bs driven from the oil pump being removed and having excessive side load on the oil pump assembly causing failure. Although that could also be caused by improper timing belt tension. AMS sells there bse kit with the oil pump shaft still intact, just with the weights shaved off.
Oil pressure is consistent with bearing clearence. Did you ever measure the bearing clearnece and compare with specs? What kind of weight oil do you use. A thinner oil might help relieve some of the pressure issues. A car with thick oil when its cold generally has significantly higher oil pressure then when the motor is at operating temperature.

 

[turboglenn]

Hence why I said why not just pull both of them out. Its easy enough when the motors out. I was talking about your current build, not your last set-up, sorry if I made it sound different.


Do you have any pictures of your ported OFH, I'd like to see just how much you did port them.

OH, okay i got you know.. My new motor does have both out with the new bearings in "out of line" to block off the passages. It's also a 9:1 wiseco/eagle H-beam combo. I know it's tough, but i want ALL of the operating parameters at their best respective specifications. I basically want more of a road race motor than a drag motor... I'd rather run in the 425 horse range for 15 minutes straight compared to being able to make 600hp for a pass or 2 at a time or not being able to daily drive it from one coast to the other. My goal is only 450 on turbo max(~400'ish daily) But i want OEM reliability. That's why i'm being a little picky about oil pressure and willing to play with some things on the spare motor to come up with something solid for my current baby that took me forever to afford to build.

The last motor was almost perfect IMO, it held up to 30psi daily beatings on E85 ( what would equal around 6 - 10 drag runs), had been run lean and just plain abused, and the only way i knew anything was wrong was through the J&S showing me an odd noise on cylinder #1. I honestly didn't even check it, i just knew and sure enough when i did the swap i had one rod that looked relative to a banana, so i'm putting my good 1g rods with ARP bolts and 2g pistons in it with a re-ring kit with gaskets and timing parts.

I don't have pics of the OFH but as long as i remember to check this post in the monring I should be able to get a couple..mainly what i did was bring the bottom of the opening around that little "casting circle" to the right of the hole. I took the dremel and opened up partially below it. I figure the thing son't open all the way so the first 1/4 of travel needs to be the most effective ( but i could be wrong)

I have heard some horror stories with the Bs driven from the oil pump being removed and having excessive side load on the oil pump assembly causing failure. Although that could also be caused by improper timing belt tension. AMS sells there bse kit with the oil pump shaft still intact, just with the weights shaved off.

Oil pressure is consistent with bearing clearence. Did you ever measure the bearing clearnece and compare with specs? What kind of weight oil do you use. A thinner oil might help relieve some of the pressure issues. A car with thick oil when its cold generally has significantly higher oil pressure then when the motor is at operating temperature.

MY clearances are right at .002 - .0025 on both the rod and mains as far as i remember ( the machinist did all the measuring and everything, i just put them together as an engine instead of as a rod and crank on a bench. I use 5w-30 by orders of my machinist that was his only rule to warranty that the engine will hold up to what i've planned for it daily, so i'll agree with that since it's what i always ran anyway

NOW...As for the balance shafts. I would prefer to have them gone, BUT due to what some have said about oim pump failure, i've decided that i will machine my own oil pump shaft and get rid of the weights on it.

I would prefer to leave the front one intact but without a belt on it just so it can't take out my timing belt, other than that chance i wouldn't care too much but the slightly quicker revving is kinda nice. Hopefully i can get the oil pressure under control to the 10:1 rule through modifying the OFH while using a real BSE and possibly no oil squirters (maybe NT block, or just get rid of them as some do)

We will see, the ironic thing is i talked to darren at FFWDconnection.com for a couple hours the other day and he said they don't even bother with porting PFH's, keeping the pressure in certain bounds or anything on their race engines, they just run a restrictor on the turbo. And for his warranty he specifies 20w-50 oil. WOW!!!! Talk about thick, My machinist about shit a brick when i said that's what i might run after talking with darren and that's why he said "5-30 if you want me to warranty it" Then he made some statement about an aluminum head and a cast iron block for the reasoning but honestly don't know the science behind his statement to try and come near quoteing him.

Time and experimets willll tell! Just hope i can keep playing on the cheap, but now i have to hook my OP gauge back up when i start making changes so i can monitor what goes on. After bing satisfied with the pressure and head relief valve i just hooked the dummy light back up so i at least know if the pressure goes to zero

 

[toofast82]

Thats interesting to hear the two different opinions on the oil weight. Me personally, i've ran 15w-40 diesel oil religiously for quite some time in my dsm's as well as my camaro.
I think you'll be good with leaving the front shaft in with no belt and using the bse oil shaft or fabbing your own. Its possible not running the front blockoff bearings may make up for some of any possible increase from not running squirters. I wouldnt worry about it with stock pistons either. They obviously have a benefit and can possibly be a problem. I think if you were running autocross or something, you should definitely have them. I think its kind of like the 9.3:1 factory a/f ratio.

 

[turboglenn]

Thats interesting to hear the two different opinions on the oil weight. Me personally, i've ran 15w-40 diesel oil religiously for quite some time in my dsm's as well as my camaro.

I was taken aside by these 2 largely diffeent statements myself.. I'm no engine machinist so i cna't really say why either one would be better than the other, I can see pros and cons of each, but no solid proof first hand.

I wouldnt worry about it with stock pistons either. They obviously have a benefit and can possibly be a problem. I think if you were running autocross or something, you should definitely have them. I think its kind of like the 9.3:1 factory a/f ratio.

BY this do you mean the pistons or squirters have the benefit? I'm thinking squirters since you said could possibly be a problem... I take it you mean one coming loose in the engine?

Just trying to figure out what you mean by "not worry about it with stock pistons" Other than statements on here that have surprised me i thought they would almost be mandatory on the OEM slugs since a good portion of factory turbo motors have them.

 

[toofast82]

Just trying to figure out what you mean by "not worry about it with stock pistons" Other than statements on here that have surprised me i thought they would almost be mandatory on the OEM slugs since a good portion of factory turbo motors have them.

I was talking about the squirters. They do cool the crowns of the pistons. There is that always slight chance of them coming apart/loose. I've read of many people not having problems running no squirters with stock pistons. I also read that they really dont really start squirting much until like 4k rpm or so. If your just driving around and not beating the death out of the car, I dont think it will be an issue. Of course you will be doing some beating on it but as long as its not extended highway runs! If you drive your car like you stole it, then i would definitely run them with the stock pistons. If you make your "test passes" and allow some light driving in between them, then i dont see them being them a necessity.

 

[turboglenn]

I was talking about the squirters. They do cool the crowns of the pistons. There is that always slight chance of them coming apart/loose. I've read of many people not having problems running no squirters with stock pistons. I also read that they really dont really start squirting much until like 4k rpm or so. If your just driving around and not beating the death out of the car, I dont think it will be an issue. Of course you will be doing some beating on it but as long as its not extended highway runs! If you drive your car like you stole it, then i would definitely run them with the stock pistons. If you make your "test passes" and allow some light driving in between them, then i dont see them being them a necessity.

Gotcha! I'd rather over build than under build. On this motor i put them in with red (permanant) loc-tite. If i happen to need them out i just have to heat them up with a torch and the loc-tite will goo up and loosen enough to remove them with out any issues, and that's probably what i'll do on the next motor unless something makes me use the N/T block i just go., But, both my spares apear to be in near perfect shape, cross hatches still showing, no grooves, no ridge at the top of the hole, no pistons beat up, bearings are fine etc... If i can get away with it i won't even bore the spare build. I'l just hone and throw in some new rings on the stock 2g slugs. It just pisses me off that the first machinist who built my first motor 6 years ago beat up the pistons pretty bad prssing the pins in adn out, but it's livable i guess and they easily cleaned up with a dremel and small sanding drum.

When all said and done i'll have 2 complete spare 6 bolt engines, One to sell to some one in need and still have a good spare to drive on should something go wrong on my current engine. I just feel more comfortable about beating an engine when i can look in the corner and see a complete spare ( for a poor man that's a big deal! ...that's also why i can't decide to sell or keep the 2g FWD trans i just built or how much i'd want if i did sell it )

 

[mobythevan]

When I compared NT and Turbo oil housings, oil pumps, etc I could not see a difference. I also compressed both springs by hand and did not notice a difference. Maybe some real measurement to the spring is going to be required. I still can't believe after all this time that no one has posted what they believe the difference between NT and Turbo engines are to control the seemingly excess oil pressure on a NT. Maybe after all it is just the oil relief spring.

 

[turboglenn]

^^ i agree, no one has any input on how the stock NT block keeps the oil pressure at a reasonable level *shrugs*

Today i was looking up parts and couldn't find any differences in the part #'s for the OFH parts, but i couldn't find the springs alone on the softwareat the autop parts store, I would like to have mitsubishi's parts interchange book/.pdf

It may just be that the spring is work out, but i can dfinitely tell the difference between the turbo and N/T ones i have laying around here. But, that is only one example of each and hardly enough to make a call based on these 2 alone.

I gotta go get another USB cab;e for my camera so i can upload the pic of the new ported OFH i did. It's the one where i opened the bottom around and under that circular casting to the right of the hole.

I still haven't actually tried getting the relief valve out with the damper on the car, but it looks like it might come out, if so i think i'll try that NT spring first and if that don't work i'll start clipping 1/2 coil off of the spring at a time until i find something i like or decide to trash that idea. Other than that my next plans are to either machine a new bolt that doens't pre-load the spring as much or make a spacer to do the same thing. I'd rather machine a new bolt as it would have less chances of leaking compared to doubling up crush washers or adding a spacer and another crush washer