Engine trouble

[DoubleD]

Looking for some ideas from engine pros here. I had an all brand new engine built, made a few pulls on dyno and for some unexplained reason it spun #8 rod bearing, trashed the roller lifters and ruined the lifter bores. Dry sump engine with 3 pan scavenges and one scavenge in the intake in front of the distributor. Oil feed is in the back of the block up high behind intake. My old engine feed in front with the lifter scavenge out the back. New engine is a World Products block, old one was a GM010. Is it possible the problem is with the way oiling is done or other ideas? All lines feed and return are AN12. Also was pulling about 15" vaccuum. Too much? Looking for some ideas before this is put back together ,hate to waste more money and time! Thanks

[billetbirdcage]

Lifters:

Did you check the lifter diameter and the lifter bore diameter to see the clearance before installing them? Different brands of lifters are different sizes, there has been many issues with lifters being way to loose in the bores depending on lifter/ block combination.

This lifter issue may be separate from the rod bearing issue.

You might state whether it was a steel block or aluminum?

[dynoman14]

Birdcage is right on.

The 2 things might be related or one may have caused the other, most likely the rod bearing failure first.

In 35 years of building SBC's I have never fed the block high in the back, you may have washed out the main and rod, although you said rod, how was the main back there.

With all that vacuum 3 pan on one valley scavenge you might have been sucking too much oil out of the engine. Why do you pull oil from the valley?

BTW, are you using a Peterson valve on your valve covers with everything else closed off, or do you have open VC baffles and an open dry sump tank.?

How much oil did you have in the system when this happened?
Have you dyno tested on that very engine dyno with that set-up before?

I normally put the oil in up front or at the filter pad. I am a KISS person and I stick to what works for me. The simpler the better.

Did you have multiple oil pressure gauges going to see where you had pressure and what it was?

If I am running a new system or anything different, I like a gauge at the front of the block, one at the back of the block, and one in main scavenges out of the block and out of the pan. It is easiest to purchase T connections from AQP or whoever and just tap them for small 1/8" pressure gauges. I use Wika because they are just up the road a piece and very accurate. You can use $10 ones from Ace HDWE as they are better than nothing...You are looking to establish a baseline on the stuff you know works and then compare to determine where there might be a problem.

I do the same exact thing for water, fuel and air so I can get an idea what is flowing where.

I'll check back for more info...

[billetbirdcage]

With all that vacuum 3 pan on one valley scavenge you might have been sucking too much oil out of the engine. Why do you pull oil from the valley?



Standard practice for all 4 stage dry sumps!! It most likely has a sealed lifter valley, so if you don't have one there you have to drill drain holes to let the oil drain or use the savage area that is made into the block specifically for doing that. With all the power you say you make, why would you want unwanted oil dripping on the rotating assembly. Sucking to much oil out of the engine on a DRY SUMP, this ain't no wet sump with oil needing to cover the oil pickup???? (LOL)

I'm not familiar with the World products blocks but would assume they are similar to other aftermarket blocks with priority oiling, so they oil the mains first thru a separate passage to the left of the cam tunnel. Both front and read feeds connect to this passage, so it isn't any different whether you oil from the front or the back besides one oils mains front to back verses back to front.

[billetbirdcage]

There so many things that could have happened:

Was all of this new?

Was the crank or rod's import stuff: Eagle, Scat or the like? some of them are horrible on finish and have taper in the crank journals and needed fixed before using and rod's usually need sized before being used

Did someone install the rod bearing shells wrong (Top shell in cap and lower shell in rod) which puts the chamfer on the wrong side for the fillet radius on the crank.

That's just some simple things. Also if you went from a steel block to aluminum and you/builder never worked with an aluminum one before main clearances are different due to the main housing expanding a lot more then a steel one will.

Too much vacuum will generally show up by galling the wrist pins, in higher vacuum apps you generally use a rod with an EDM'ed oil passage to force oil the pins.

[dualdj1]

Are you positive it's supposed to be rear feed, front scavenge? Because looking at the spec's on the different Motown blocks, they are all listed as:

Oil System Features: Integral boss for front feed, boss for rear scavenge

[billetbirdcage]

You could be right, I haven't even looked at a world product block but was assuming it was similar to a dart and others that have one feed in front and one in back and one scavage in back.

He did say one savage by dist,so assuming it's a SBC and not a SBF that would be in the back.

[dualdj1]

You could be right, I haven't even looked at a world product block but was assuming it was similar to a dart and others that have one feed in front and one in back and one scavage in back.

He did say one savage by dist,so assuming it's a SBC and not a SBF that would be in the back.

yeah not sure either, I was trying to find a good picture, or some exact instructions from World, but don't see anything really. I've found their descriptions to sometimes be inaccurate, or at the least confusing, lol

[billetbirdcage]

I ain't found a picture worth a crap either, but your right something may be wrong here as I don't think they have dual feeds (front or rear) and then a scavage section like other blocks.

Still really don't know what block as far a steel or alum, that could make a difference.

I also wonder if he doesn't have the scavage made into his intake to scavage out of a stock block with no scavage area and used this on this world block. That might explain why he says in front of the dist.

[dualdj1]

yep, again no clue, but if the lines were reversed, that would definitely cause the problem.

[dualdj1]

dig enough and you occasionally find something (it was bugging me)

http://www.theengineshop.com/enginebuilders/techbulletins/Motown%20II%20Engine%20Block%20-%20Oiling.pdf

looks like (if it's a Motown II base) it could be either front or rear.

[billetbirdcage]

The way they have it shown, it has 3 inlets - 1 front and 2 in back on opposite sides but doesn't show a scavage unless one of those 2 in back is supposed to be a scavage but what they have drawn shows both rears are feeds also.

If that is the way it is and he hooked there to savage it would be trying to suck the oil out about as fast and it could come in and might be why the last pair of rods is what went first.

[DoubleD]

Hey guys thanks for you input. Alittle more info this was all new parts SBC iron block. Its the same block as in the download. The oil feed was plumbed into the "C" port on the right side rear of the block with the gallery return tapped into the intake between carb and distributor. That is kind of what i was wondering about...peoples thoughts on. My old 010 block the feed went into the front of the engine above timing cover and the valley scavenge was tapped out of the back of the block not out of the intake. I didnt personally put this together but engine builder cant tell me why it happened. Thanks again

[sj valley dave]

Our aluminum engine is set up that way...feed to the front of the block...3 scavenge pick ups in pan and 1 out of right rear lifter valley...5 stage Wulff

[dualdj1]

Hey guys thanks for you input. Alittle more info this was all new parts SBC iron block. Its the same block as in the download. The oil feed was plumbed into the "C" port on the right side rear of the block with the gallery return tapped into the intake between carb and distributor. That is kind of what i was wondering about...peoples thoughts on. My old 010 block the feed went into the front of the engine above timing cover and the valley scavenge was tapped out of the back of the block not out of the intake. I didnt personally put this together but engine builder cant tell me why it happened. Thanks again

In that case I really don't think it was a problem with your plumbing; it doesn't matter which one of the C bosses you feed to, they all handle pressure input fine, and if you're scavenging from the valley that's acceptable as well. So it shouldn't be a problem with the way your dry sump is plumbed, at the very least.

Did you have a pressure gauge on the block somewhere? How did the rest of the bearings look? It does seem like you either had #1 wrong bearings (crank or rod), or #2 wrong diameter lifters as noted by someone else. Only other possibility was the pump was connected wrong, is bad, or pressure regulator is stuck. But without knowing what the pressure was while running, is hard to say.

[DoubleD]

one mistake we know of is the pressure guage was hooked up at the back of the block and that is straight across from where the feed went in. So i believe the reading was inaccurate because it was reading from the pump and not through the bearings. All the other bearings just had some scuffing from debris. Also never showed loss of pressure on oil thats why i believe reading was wrong. Originally only caught the problem because there was a drastic drop in HP from one pull to the next.

[andy16]

i agree w evrbody else i see no real prob w oils system except the oil press guage deal. its kinda wierd to do it backwards but i see no real problem. sounds like your figuring it out. prob a case of the brand new blues... rarely have i bought all new stuff and not have to "fix" something. sorry to hear that tho

[dualdj1]

one mistake we know of is the pressure guage was hooked up at the back of the block and that is straight across from where the feed went in. So i believe the reading was inaccurate because it was reading from the pump and not through the bearings. All the other bearings just had some scuffing from debris. Also never showed loss of pressure on oil thats why i believe reading was wrong. Originally only caught the problem because there was a drastic drop in HP from one pull to the next.

shouldn't make any difference where the gauge is in the system. pressure is pressure, if there's no resistance on the other end (ie an open hole, etc), you won't build pressure. So if you didn't see a drop, you didn't have an oil pressure problem (supposing there was no blockage somewhere). You can verify that there wasn't a blockage by pumping some oil through the inlet and see if you have oil coming out at the mains.

More likely (though not sure how this would hurt the lifters, unless that was unrelated), you just got a bad set of bearings. Have a buddy that built engines that had problems with coated bearings he was getting for a while. switched types/brands and hasn't had problems since.

[perfconn]

Could be something as simple as the wrong bearing clearance on #8

[DoubleD]

Thanks again everybody. Builder swears he checked all clearances and mic'ed everything as he was building it so just looking for other thoughts.

[grt74]

i reading and thinking this may sound stupid but here we go, did you prime the system with a drill 1st and get good pressure before you started cranking her,ive seen that before with all new parts and no one primed the system real good before cranking it,if she fired up real quick and rpms got up to 5000 it may have hurt it right from the get go,just a thought

[dualdj1]

i reading and thinking this may sound stupid but here we go, did you prime the system with a drill 1st and get good pressure before you started cranking her,ive seen that before with all new parts and no one primed the system real good before cranking it,if she fired up real quick and rpms got up to 5000 it may have hurt it right from the get go,just a thought


or didn't use good enough assembly lube. always a possibility, though less likely.

[dynoman14]

DD,
I think you can break it down to a couple main things that made #8 fail. Too much oil pulled from that main, or improper bearing clearances or bad bearing. I would have to see the bearing to make a better guess. How was the rear main?

Billet,
I appreciate the primer on how dry sump systems work. I well know how a dry sump system operates as I have built tankless dry sump systems ( saves 50# ), segmented pan systems as well as the cam tube oiling system along with submerged valve train systems, well before many Cup teams even heard of it. My first dry sump NASCAR 2-bbls had these systems in place in the late 80's. Upon race winning tear downs I was asked not to bring some of these systems back although they were 100% legal by rules. Following rule books had rules in place to prevent me from running this stuff again.

My point is; since there are 3-4 suction stages and only one pumping stage. it can be possible to over scavenge certain areas of the engine while not losing visible oil pressure on the gauge.

[perfconn]

Dyno,
You may be the smartest engine builder ever but you are talking out your a$$ when you say you can over scavenge on a drysump system.Anyway how in the world could you possibly pull vacuum on a main bearing? Segmented oilpan maybe but I'll bet you he didn't have a segmented pan.3 or 4 scavenge stages and only one pressure stage is s.o.p. for dirt track.Beside all that,if it were possible to over scavenge,he would also had trouble out of #7 rod bearing also and the #4 and #5 main bearings.That is if he had a segmented oilpan.Otherwise its physically impossible.

[jedclampit]

The exhaust fan must be off in the dyno room again!

[bob62]

The exhaust fan must be off in the dyno room again!

Not a chance Jedclampit, the only real reason would be a half filled windscreen washer bottle, that will cause low oil pressure in a SBC DLM engine any day of the week. I have tested this on my dyno 400 hundred times in just the last week alone !!!

[jedclampit]

LOL! Yep!

[Egoracing]

The exhaust fan must be off in the dyno room again!

He put in a fan??? Must be why he was looking at the posts for so long without posting anything, OR he was hoping some things would go away!

[DoubleD]

Thanks Again for all the input guys. Engine just had a simple pan with screen in it. I do have alittle more info. This is a spec engine just as my last. The old engine had 60-65psi oil pressure with a 5-stage SCP pump. Put the same pump on the new motor and when i was @ builders when first fired it had right at 100 psi @ idle. I questioned about it , just got a " well its fresh just need to turn the pump down." Well forward several months ,builder still hasnt fixed it and after sitting in stands all summer, a buddy offered me his spare engine . Went and got my oil pump, cleaned it out, put it on borrowed engine....60-65 psi as soon as fired. Am i reading too much into this that builder just plain f**cked -up and had something too tight in the new one?

[let-r-eat]

Hard to believe a competent builder wouldn't know the cause upon inspection. Hope you get it ironed out. The oil pressure deal seems fishy to me.

[lazermod3]

Thanks Again for all the input guys. Engine just had a simple pan with screen in it. I do have alittle more info. This is a spec engine just as my last. The old engine had 60-65psi oil pressure with a 5-stage SCP pump. Put the same pump on the new motor and when i was @ builders when first fired it had right at 100 psi @ idle. I questioned about it , just got a " well its fresh just need to turn the pump down." Well forward several months ,builder still hasnt fixed it and after sitting in stands all summer, a buddy offered me his spare engine . Went and got my oil pump, cleaned it out, put it on borrowed engine....60-65 psi as soon as fired. Am i reading too much into this that builder just plain f**cked -up and had something too tight in the new one?

Remember DoubleD;these professional so called engine builders can do no wrong!And if they do screw up,they won't admit to it.

[dualdj1]

either something too tight or a blockage in the oil passage