Iam running a 392 stroker moter in a race boat an have lost the bottem end twice. it lookes to me like a starvation issue. i believe i have made all the oil mods needed for this block. i am only turning the moter 68oo an cant figure out whats going on. i have had my navigaters eyes glued to the pessure gauge which allways reads positive. if any body can help or has experinced this type of problem in the past i would appreciate it
392 stroker oiling problems
- Thread starter daryl h
- Start date
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fishy68
Tyr Fryr's Inc.
Just saying you "lost the bottom end" is a wide statement. If you can elaborate on what exactly happened (spun rod bearing, scorched bearings, etc...) that would give us somewhere to go. Pictures are worth a thousand words too.
Also was it the same problem both times?
Also was it the same problem both times?
spun a couple mains first time. had crank turned an straitened+ line honed. second time i caught quicker. was just starting to eat them. i am thinking starvation but wondering how to fix it second time warmed up really good, checked the filter,was good. ran it around gradually increasing the rpm,s for about 5 minutes, checked the filter, was good. then when i turn up the wick probably 6500 rpms i have metel in the filter. first time all was well till i steped up the rpms but idid not kheck the filter along the way.
fishy68
Tyr Fryr's Inc.
I'm not an expert by any means but hopefully this might help. I had a similiar problem on my 360 first go around. Didn't actually spin the main bearings but it did spin a rod bearing and the mains weren't far behind. When I took it apart the main bearings were collapsed and would no longer stay in the block on their own. Talked to my machinist who is also a small block Mopar racer and we figured out it was cause I was running too much total timing (about 40 degrees). My bad.
It sounds like you did all the machine work correctly. And since you said your not seeing the pressure drop on the gauge but it's eating the main bearings I would look at total timing to see where it's at. If it were starvation I would think you'd see the pressure gauge drop.
It sounds like you did all the machine work correctly. And since you said your not seeing the pressure drop on the gauge but it's eating the main bearings I would look at total timing to see where it's at. If it were starvation I would think you'd see the pressure gauge drop.
grumpuscreature
Resident Curmudgeon
Did the same mains spin the second time? If so and the engine is out of the car, drop the pan, pressurize the oil galley and look for leaks from the main oil gallery at the pan rail. You could do it in the car but it's messy and a PITA. Sounds like you may be the victim of oil gallery core shift and the stroker clearance notches broke through in a couple small spots.
fishy68
Tyr Fryr's Inc.
Mine was at 40 total when it happened. I have since recurved the dist. and bought a dial back timing light so I know where it's at for sure and don't let that happen again.
I haven't had any experience with a stroker but from what I've read 36 sounds about right. Give or take a couple of degrees depending on the head design. You can tell by reading the plugs to see for sure.
mikedevore
Well-Known Member
Find Another Machine Shop!
daredevil
Well-Known Member
you didnt mention valve train mods. Did you change to roller ? if so the oil galleyys may need to be bushed as the lifters are losind oil when theyre in the bottom of the hole. and are you sure youre not missing a plug inside the block at the distributor?
daredevil
Well-Known Member
reread your postand dont think youre missing the oil plug its under the distributor ,inside at the back of the lifter galley. im not familiar with dry sump so i cant be much more help. Did the crank turn freely without the rods. maybe the bearings need chamfering for the radius on your crank. just guessing at this point
yes it spun perfect. measured everything. wondering if it might be the pan? running it in a sprint boat, with sharp turns left an right. live in a small town in idaho an every moter builder i have talked to in my area has never done much with small block mopar when it gets much past stock
fishy68
Tyr Fryr's Inc.
It sounds like you definetly need a well baffled pan suited to your application if you don't allready have one. I have to say that it sure sounds odd that it spun main bearings before rod bearings unless the clearance on the mains was alot tighter. The rods being farthest from the oil supply usually go first. Did you cleck the clearances when you assembled the engine? Should have had at least .002-.0025 on the mains and .002 on the rods. Looser clearances help keep them from spinning but also require more oil so a hv pump and extra capacity is a good measure.
moper
Well-Known Member
Exactly what was done for machining? When was the oil pump last checked by it's manufacturer? Where are the pickup lines, and how many stages? What has been done in terms of oil system mods and oil windage control? What cranksahft? What horsepower level?
the block was tubed, notched for the stroker, an the oil filter housing cut back for the dry sump setup when i got the moter. i did not do any more to it the first time i put it toghether. they had let the valves get out of adjustment an lost one when i got it. second time i turned an straitened the crank an line honed it. cant tell that the caps are chattering or walking, just looks like starvation. running a 4 stage aviad pump with three suckers out of the pan. they are 12,s. the feed runs through a oberg then to the block. its a 10. running a stfehs pan with a built in screen but no windage tray. pretty sure its not the pump because i ran it on a big chevy after i lost this moter. the crank is a steel 3.79 . has a 8 bolt flang. never have had this moter on a dyno but i would guess its puting out somewhere around 650 horses. thinking grump might be on to something with the notches or core shift. have noticed that when the block was tubed the 2 pieces are not perfect. there is just a little lip where they come together in the middle. could this possibly cause a bubble or enouf of a restriction to cause a problem? also i feed the chevy with a 12. looking at the tube in the block im thinking a 10 should be plenty. any ideas?
66dartman
Well-Known Member
When the block was tubed, what size were the main galleys drilled to? They should be drilled to 9/32" through the tube. And I would make sure that there is no flash left on the inside of the tube causing a restriction. Also, it seems that I saw in an older mopar engine book that they were adding oil lines in the valley for more volume to the mains at higher rpm. The line would run from the back to the front, right side to left side. Anyone else seen that mod? It might help. 2c
Guitar Jones
aka Angry Johnny
When you tube a small blocks right oil galley you need to ream the galley first for an oversize tube so when you peen the tube down for lifter clearance you don't crush the tube completely. You can create one hell of a restriction there.
You may also look to be sure the left side galley was properly blocked at either the front of the block or at the #1 main. If oil is still going down the left galley you are losing a bunch.
Since the right side lifter galley feeds the mains you may want to be sure it's been properly drilled from the main passages up to the galley.
Should I assume you have properly blocked the original wet sump oil pump and it's associated passages? Something else to look at.
There is also a soft plug in the wet pump passage that goes out to the oil filter passages that separates the two. If this is not there or not installed correctly you could have starvation problems as well.
Sounds to me like you need a new engine builder/machinist that is familiar with the LA engine. Most are not because they aren't real popular with the knuckle dragger crowd because you can't just assemble one out of the Summit catalog, you actually have to build it.
You may also look to be sure the left side galley was properly blocked at either the front of the block or at the #1 main. If oil is still going down the left galley you are losing a bunch.
Since the right side lifter galley feeds the mains you may want to be sure it's been properly drilled from the main passages up to the galley.
Should I assume you have properly blocked the original wet sump oil pump and it's associated passages? Something else to look at.
There is also a soft plug in the wet pump passage that goes out to the oil filter passages that separates the two. If this is not there or not installed correctly you could have starvation problems as well.
Sounds to me like you need a new engine builder/machinist that is familiar with the LA engine. Most are not because they aren't real popular with the knuckle dragger crowd because you can't just assemble one out of the Summit catalog, you actually have to build it.
moper
Well-Known Member
The tubes may not line up perfect. That means nothing. But, there are other mods to do. As was mentionned, the mains should be enlarged. I go to 5/16, because that's the size of the passage's entry. You should also have a cross over tube. Was it the #3 and 4 mains that were the problem? I dont think I'd run a -10 either. Make the feed at least as big as the suction lines. You dont want the line to be the restriction, you want the block feed passage to be the restriction. Do you have a crank scraper? How deep is the pan? A windage tray and scraper combo would go a long way to help get the oil down away from teh crank quickly. Also, additional drainage holes in the valley help. Look at the parting surfaces of the caps. If you can, get a camera and post some pics of the bearings (front and back) and the cap's mating surfaces. Your guy didnt get the oiling system right. Only parts of it. Honestly, ship it to Ryan at Shady Dell Speed Shop. Dont find one local. Find one that can do the work the right way. Also, at 650hp, your stock block is beyond maxxed. For that application, you should have replaced the block with something better.
chryco 557
chryco 557
No where did you mention the cold and hot oil pressures . That`s probably the first point of concern here . Do you recall what that was?
Chryco 557
chryco 557
chryco 557
h had 85# of oil pressure if i remember right an pleanty of heat. First big mopar I have ever tried to build. I do enjoy building the moter as much as racing. I wont learn anything if I send it out an have some one else build it. the first couple of Chevys I built had problems too but now I am pretty profishant at it. I have heard of the cross over tube but was not using one. Could you elaborate a little on it? Read an article on feeding it from the front an back. have you ever used a duel feed system? I am a little concerned with the pan. What kind of pan would you recomend for my application? I do have a good block but i would like to figure out the oiling system before i use it. I do not have a camera for the computer but still want to learn how to put it together right.
moper
Well-Known Member
The reason I suggest you not learn is for financial and sanity reasons...lol. You can never learn enough about oiling. The first few things are, the crank can't flex much, the journals MUST be flat, the clearances MUST be right, and the main caps can't be allowed to move under load. If any of those is not right, the oil film breaks down regardless of volume or pressure. If you can measure that stuff (not plastigage, I mean micrometers and dial bore gages) and knwo it's right, you need to address the performance end of things. You said "full roller" top end. Means what exactly? Which lifters are you using? If you run a solid roller in a small block, you should have started with lifter bore bushings, not tubes. $500 there would have saved some aggrivation, albeit it might have been more like eliminating one weak link of many. And if you went tubes, both sides should get them. That's because certain lifters can uncover oil passages when up on the lobe, causing oil pressure loss where you can't see it on a gage. And because the lifter galley feeds the mains, the mains will feel it, and show marks from oil starvation. Now, you could tube both sides, and then enlarge the main feeds, but with clearances over .0025" and a big pump, you may run into the oil moving so fast thru the tube, that it has trouble making the turn from the tube to the oil passages to the mains. That usually effects high rpm engines and you will see starvation on the #3 and 4 mains. That's where that crossover comes in to play. Obviously any damage to the oil film on the mains, is problems on rods. You do run full grooved main bearings, yes? I'm not sure what you mean by "two lines..." For oil pickup you mean? Dry sump is it's own animal. I would keep what you have. From what you are saying, it's lack of mopar experience and poor choices by yourself or the shop, not the dry sump system or pan. The books on the market today the one on "Big inch small blocks" by Szylagi or something like that, it goes into a little, but not much. The older DC engien book, and "How to build Mopar big and small blocks" books are out of print now I think. You mimght look up the MP circle track book(s) tho. They should go into more detail. If you dont know, learn, then tell the shop what to do. It will be cheaper buying $50 in paperbacks then doing it a forth time. And I have no single book with all the mods. They all take the authors' singular opinion and simply state that, instead of telling all...lol.
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