Need advice on built motor gone bad

[Bastard1g]

I am tired of this motor. It is a stock rebuild. 6bolt with topline pistons,rings and bearings. Balance shaft eliminator kit,arp rod bolts and head studs, metal hg.

After 700 miles the motor has 150 psi accross the board which is low since stock is 164. Smokes intermintently at idle and decel. doesnt smoke at wot though. I am planning on doing a wet compression test this weekend and maybe then a leakdown. What do you guys think about this? It has less than 800 miles on it but should still have higher compression and not smoke that bad. It didnt start smoking bad till about 100 miles on it. Any advice before i get too worked up?

 

[GTM]

...

After 700 miles the motor has 150 psi accross the board which is low since stock is 164. Smokes intermintently at idle and decel. doesnt smoke at wot though. I am planning on doing a wet compression test this weekend and maybe then a leakdown. What do you guys think about this? It has less than 800 miles on it but should still have higher compression and not smoke that bad. It didnt start smoking bad till about 100 miles on it. Any advice before i get too worked up?

Did you follow the piston maker's break-in instructions? What were they?

Cheers,
GTM

 

[Bastard1g]

I got topline pistons and rings, I couldnt find any break in tips or instructions. I think I did the break in just fine. I didnt dog it out, but I put load on the motor to create heat. I hear that different types of metal have different times to fully seat. I need to find out what kind of metal is used for the topline piston rings. I cant find that out though. Oh well.

 

[GTM]

I got topline pistons and rings, I couldnt find any break in tips or instructions. I think I did the break in just fine. I didnt dog it out, but I put load on the motor to create heat. I hear that different types of metal have different times to fully seat. I need to find out what kind of metal is used for the topline piston rings. I cant find that out though. Oh well.

I don't know who "Topline" is though I've seen the name many times here. A search of the internet found nothing so unless you have a web site or other info I can't make any suggestions. It it possible they never seated. I would need to know a lot more before I suggested the Comet treatment.

Cheers,
GTM

 

[Bastard1g]

I found thier website but no useful information. http://www.toplineauto.com

I am putting a new turbo on next week. As soon as I get the turbo, I will drain the oil and inspect it for any metal shavings. I didnt see any metal shavings in my other oil but I am going to look it over anyway.

 

[Bastard1g]

What is the comet treatment?

 

[GTM]

What is the comet treatment?

It very much sounds like your rings did not seat. I don't have any idea what went wrong, if you got ring gaps to wide, improper ring stagger, wrong pistons, wrong rings etc.

Many years ago when rings would not seat we would dump/sprinkle Comet cleaner down the carb while reving the engine. Probably not more than a teaspoon per cylr would do the trick. Comet is one of the more abrasive cleaners but worked quite well. While working for Nissan, we had to do this with several new cars over a 6 month period and never had any come back for a complete tear down.

The problem I have with this is the fitting clearances are so much smaller than back then and I knew the factory had correct fittings so there was no doubt. We would then take the car out and use the standard break in at that time which was to use 2nd or 3rd gear lugging at 20mph and then wide open throttle accererate to 50mph. Normal deceleration back to 20 and repeat the full throttle process for a total of 6 times. This would get things hot but not so much that it would gall pistons or rings because the duration was limited. Needless to say you would need some open road where you can do this for you don't want to drive too many mile after the Comet treatment and the break in. _However_ many new piston and ring makers are NOT posting any special break-in periods which has me concerned even mentioning these things.

I cannot recommend / endorse any of this since I'm not aware of what can happen with these new tight fitting engines. If you want to take the chance it's your business, the choices are to give it a try or pull it apart and recheck everything. I did a quick search of the Internet and only found 1 site (motorcycle) where anyone even knew the process if that doesn't make you insecure...

It would be best if you discuss the problem with TopLine, hopefully you kept all the receipts and packages so if they sent the wrong parts you can make copies and pictures.

Cheers,
GTM

 

[Bastard1g]

Yea, I have 750 miles on that motor so I may wait a couple of weeks before trying that, but I will deff. try that before tearing my motor down. I am pretty sure they are the right pistons and rings. Compression was 150 accross the board last time I check a couple of weeks ago. I dont know if they just didnt seat or if the rings were not gapped right. It still burns a lil oil at idle but not as bad now. I need to get a hold of topline because I hear different kinds of material to make rings takes different amounts of time to have complete break in. Maybe the oil I used was bad. I used the shit we have at work motorcraft 5-20 synthetic blend. I know its vegetable oil but I figured I could get away with it since I will have to change it very frequently anyway. Its just weird how its fine at wot but at idle or slowing down it smokes and builds an assload of crankcase preasure. You think it may help if I connect my pcv valve? My crank case preasure at wot sucks though, when I get on it, I get oil wanting to spray everywhere. My valve cover gasket which was a new mitsubishi one got messed up pretty bad.sometime this week, I will do a dry and wet compression test.

 

[2bar]

One of your problems is that you can not brake in new pistons with any type of synthetic oil. Once the rings are broken in you can switch to syntec oil but you will never get the rings to seat correcty. Use a 5/30 also. When installing your pistons do not coat the whole piston. Use your hand to slightly coat the cylinder wall, Put some oil on the skirt off the piston and spay some on the rings them self and install. I use and squirt bottle to squirt oil on the piston.

 

[2bar]

If you do not have your pcv valve hooked up you have no way to equalize your crankcase pressure. So yes hook up your pcv valve

 

[Bastard1g]

Yea, i may try to get one in a few days. I also have to find out where the power steering fluid is coming from. I have a power steering flui leak somewhere from the pump. Its only bad when I haul ass though.

 

[GTM]

One of your problems is that you can not brake in new pistons with any type of synthetic oil. Once the rings are broken in you can switch to syntec oil but you will never get the rings to seat correcty.

I saw that but he said it was a blend which could mean it only has 15% mineral oil and the rest is petroleum. If it is a much higher blend then it could be a candidate for the Comet treatment with the oil that's in there and then switch to a regular petroleum for the "normal" break in period.

Cheers,
GTM

 

[bullettdsm]

Hey guys this sounds a lot like railroaded rings. Someone on this thread alluded to the ring stagger. If they are railroaded then you would get the high back pressure in the crankcase with the lower (but not low unless ring gaps lined up exactly) compression. But I am trying to figure out now if you allowed the block to breathe. Did you just block off the PCV hole. That would not be good. Crankcase needs to breathe. This would prevent the rings from seating properly. Though if you did that you would probably have some leaking gaskets going on (i.e. valve cover). Did you watch for your ring gaps when installed? This would suck because the fix, while obvious, would not be fun. Also, I wish more people would watch for this, no synthetic oil on break in. For what it's worth we have had engines that pump up compression after 700 but in all honesty we never did find out why. You might want to try dumping the synthetic and running straight 30w. But unfortunately you already have the synthetic coating and you're past the critically ring break-in time.
Geez, I don't seem to have anything positive to say in this post. Sorry,
MB

 

[Bastard1g]

How much comet should I need to add to the cylinder through the spark plug hole? I am scared of putting too much in and burning up a piston. Also, yea I was cheap and used the pump oil at work. the pcv valve is just onhooked on the valve cover side and the air nipple on the intake manifold is being used for a boost source for my bov/ dejon tool bov mod. I will switch over to the new oil tommorow when I put my new turbo on. Is it a bad idea to redo the breakin after I put a new turbo on? Cause I have a crapped out blown 20g on there now.

 

[Big Woo]

I would not arbitrarily consider 150 psi across the board a bad reading. According to Haynes the standard cylinder pressure for a 6-bolt motor with stock pistons is 164 psi, and the service limit is 121 psi. Valve timing will also play a key role in what the cylinder pressure measures during a compression test. For example if the intake cam is retarded it will close later thereby reducing the number of degrees of crankshaft rotation available for the compression stroke while the intake valve is closed. Just so you know the intake valve does not close until after bottom dead center, so the piston is already starting up on the compression stroke when the intake valve is closing.

Additionally if you are using a metal head gasket or one with a greater thickness than the stock one then you may get a slightly lower cylinder pressure reading, therefore you will need to lower what one should consider the "standard service pressure"

When you did your rebuild did you replace the valve guides? How about the valve seals? Were the valve stems worn or tapered at all? Were the old valve guides cracked where they protrude into the bowl area? Do you know what the measured valve stem Clearance was? These are all items that could cause or contribute to oil smoke. I would expect a valve guide clearance problem to not smoke much during WOT, since this is a turbocharged application and the intake and exhaust pressure during WOT (full boost conditions) would tend to force the oil up the guide into the valve cover area. I.E. it will follow the path of least resistance. If your rings are leaking it will try to pressurize the crankcase, and if your crankcase ventilation system is not adequate then you may see other signs of this like the oil dip stick being pushed out of its tube for example. By contrast a ring problem will generally smoke at WOT since the ring package can not adequately scrape the oil off from the cylinder walls, and it burns during the combustion process.

I have used the Top line pistons and rings before. I have had no problems using them in the past. But they are a less expensive alternative to forged, and depending on what year 1st gen motor you bought them for they either came with a Chrome or moly top ring. One problem I noticed with the Top line piston is this, if you buy a set of 2G pistons from them the wrist pin diameter will be the 2G rod mate of 22mm, but the dish in the piston will be the same size cc wise as the 1G piston. So yes if you go this rout you are not going to get a 8.5:1 compression ratio, it will be more like 7.8:1 static. If you want the 8.5:1 compression ratio in an aftermarket cast piston the Mitsu and ITM pistons have the correct dish volume. There may be others, but I have not used them to verify this.

 

[Bastard1g]

It is a 90 block. I dont know what year head, it was a non turbo head cause I had to put in turbo cams and the banjo bolt for the oil feed line. The pistons were for the regular 6bolt rebuild kit. My cam timing is dead on. The block was decked and the head was milled when it was prepped. Should have new valve seals in there, that what I paid for. I also have the mitsu 4 layer metal hg. The block was bored .020 over I cant think of anything else to say about it. What was weird is that I did a compression check around the time I first got my motor running and it said 160 on cylinder 1 and the rest read 150. Now all of them say 150. I plan on running another compression check on it in the next few days and I will let you know whats going on. It doesnt smoke as bad as it did before but still smokes a lil bit.

 

[blue1]

I would look at your valve guides and seals at idle and decel is when those two areas play the biggest part, comps are even and quite well within limits!

 

[Bastard1g]

I am going to run another compression check in the next couple of days. I am getting massive crankcase preasure under boost. I backed off my oil filter again today and it was almost a tragic experience. I need to find out how to vent the crankcase preasure better while under boost. Blowby sucks.

 

[4GSixty3]

Hell, 150 across the boards is pretty damn good. I just rebuilt my motor and used another method of break-in that a few people use on here and my compression, last time I checked, is around 130-140 in all cylinders. Still runs like a beast though.

 

[Bastard1g]

The low compression isnt so bad, its the blowby that sucks ass. Today my car almost died because I was getting on it and the filter backed off and smoked up the streets.

 

[NinjaTech]

Couple things, blowby should not cause your oil filter to come off.. That sounds more like an issue of it just not being tight enough on the car.

I would definatly do a leak down test. Those numbers sound fine for the motor. You said you had a crap turbo on it right now? Is it possible your getting oil leaking out of it? Maby it is blowing smoke will at WOT but you just cant tell from in the car?

Is the smoke blackish or blueish? Is it possible your running freaisly ritch at idle? Check your plugs to see if they look like they are being run rich? Or is they look like they are starting to get oil fowled?

Just throwin out some other possible ideas.

Pat

 

[Bastard1g]

It has a new turbo on it, no oil in the ic piping.

I have a wideband a/f ratio gauge and it does idle at 11:1 but anything other than idling, its where it should be. I am getting my friends pocketlogger tommorow so I will log everything and let you know what I find.

I torqued that oil filter down good, I dont know why it backs off sometimes.

I dont understand how 150 psi is fine when I am supposed to have 164, allthough I have a 4 layer metal hg, my block was decked and then head was milled.

The smoke is deff. oil I have to top it off every now and then. Doesnt burn alot, but after I slow down to stop at a light, I notice some smoke.

 

[Bastard1g]

Also, I still need to know how much comet to sprinkle in my motor? I just want to make sure I dont put too much in and destroy my motor.

 

[bullettdsm]

I know this sounds strange on a new engine, but did you try to pump up your cylinders with oil to see if your comp comes up. With the crankcase back pressure that you are getting it sure does sound like ring stagger or, at the least, back ring seating.
MB

 

[snox135]

One of your problems is that you can not brake in new pistons with any type of synthetic oil. Once the rings are broken in you can switch to syntec oil but you will never get the rings to seat correcty. Use a 5/30 also. When installing your pistons do not coat the whole piston. Use your hand to slightly coat the cylinder wall, Put some oil on the skirt off the piston and spay some on the rings them self and install. I use and squirt bottle to squirt oil on the piston.

Untrue, they break in motors all the time with synthetic oil. Corvettes and many other sports cars come with synthetic from the factory.