Tired of rod knocks...
 

about to put my third set of bearings in my 7mgte in 3000 miles -__-. I did a full rebuild and all of my clearances were PERFECT (under .002) everything was torqued to spec. i did the bearing matching and everything I checked the oil pump and clearances were PERFECT and it only had 30k on it. I shimmed the op and the cooler recirc.I replaced the oil squirters and the cams spec'd PERFECT as well I have an aftermarket oil cooler on the stock system (no filter relocate) I run 10w30 conventional oil and drove it VERY EASY on break in 1500 miles. i have the 6m crank and rev to redline alot but its stock rev limit it stops at 6500-6700 ish so it isnt over revving. I'm gonna put one more set of bearings and a new op in it and hope for the best, but other than replacing the psi line from the pump to the block and a filter relocate, what else will help with my oil issues. are the 7ms known to have rod issues from harmonic balancer issues or from being solid mounted? (miatas are known to eat rod bearings if the balancer is loose) also how much power are the stock rod bolts/main bolts good for? I'm making 325whp maybe i'm just over stretching the rod bolts?? i'm at a loss and about to just scrap my 7m i'm tired of the oiling on it 4psi at idle is just stupid... I'd just hate to throw out all the time and money i have into the swap/rebuild... I build engines for a living and have NEVER had an issue like this before on engines that see 8k + all the time and make well over 7-800 hp. Maybe I was misinformed but from what i gathered the stock internals should handle about 400hp without needing upgrades besides pistons... any upgraded pumps available maybe a gerotor pump rather than a gear pump????

EDIT, Sorry, not patient enough to read one giant block of text today. I see you've checked most of what I listed. I'll reread it later and see if anything else comes to mind. You have a thermostat on the cooler? and is it a full flow cooler setup or bypass?



Your issues are unique... most people track down and fix the real problem by set number two. ;) Seriously though, people make a LOT more power than you're seeing and use the stock pump without issue. Some shim the relief valve for a pressure bump but it's not so common any more (just one of those things which everyone recommended until someone actually researched the oil system and found it sufficient to support 700RWHP... ya know?)

Have you replaced the pump? The oil squirters? Pulled the pistons and made sure they're sound? Checked that the cylinder bores are true? Have you measured the crank to ensure that it's straight? If it's been pulled and improperly stored without supports it may warp from its own weight. Have you measured the journals on the crank and the rods to make sure they're true and really round? Measure the rods with the caps bolted and torqued. Have you made sure the oil inlets/feeds in the rods and bearings are unobstructed? There's a lot of stuff which could contribute to your problem. I'd start with what's mentioned... if the pump hasn't been replaced I recommend you replace it; make sure the replacement is for the GTE and NOT GE. Replace the oil squirters.... they're essentially a controlled leak and can open up at too low of a pressure over time... same for the stock POS oil cooler setup actually (You ARE running an oil cooler, correct?).

400 at the wheels is about the limit for a healthy GTE (rebuilt, it actually take more but requires upgrades apart from the long block). If you picked up a used engine from Joe Blow then you can only guess what you're going to get. You see very little complaint about rod knock with these engines given the age and amount of abuse they usually see; See it more with JDM engines or domestic if they've been sitting in someone's yard.

I did all of that i shimmed the pump and thecooler relief the squirters were all replaced the pistons are forged and the rest of the internals are stock. EVERYTHING was thoroughly cleaned and measured before assembly. Yes I am running a VERY LARGE oil cooler. I'm beginning to think the pump i used is from a ge... i never even thought itd be different i had 3 engines and 3 pumps 1 engine was a ge and it had 30k on it so i think i used that pump.. do the pumps look identical?

You threw in an unknown, used oil pump? lol. :stickpoke

I added an edit to my previous post, I didn't read your entire post so I missed a lot of what you've done. Have you had the crank out for any length of time? Has everything been measured and proven truly round? I presume you've got a thermostat on the oil cooler (I REALLY hope you ditched the stock pressure based piece of shit)... Is it a full flow or bypass setup?

its the stock cooler setup with different lines and cooler.I figured I didn't need much of a cooler upgrade being that the turbo is also water cooled and i'm not making any real high #s. my oil never gets all that hot even after a full run on the track you can grab the cooler and lines leading to and from it and it won't even phase you plus if you pull the dipstick and touch the oil its pretty cool so i never even bothered with a gauge for it. and no the crank was out of the engine for maybe a 48 hour period then reinstalled and was stood on end as it should be. the used oil pump was only because the stock engine in my car died and this was the only option i had NO cash to throw into it and after measuring all the clearances i wasn't too worried about it. do the ge and gte pumps look the same just flow different?

With all the trouble you're having I'd make sure the crank's straight anyway... It's not the stiffest of metal, and they're quite long. I have seen one go south pretty quick myself (never checked one that was out for less than a week though, but still not a bad idea).

Yes, they look the same but the GTE flows a good amount more to account for all the additional sources of pressure drop: turbo, cooler and oil squirters. I'd guess 25% more or so.

If you can touch the oil it's running too cool. The stock cooler is PRESSURE based, not temp. If the valve is stuck open or the spring is weak it'll stay open, over cool the oil and tank your oil pressure. I HIGHLY recommend you just ditch it and get a thermostat in there.

How are you measuring the oil pressure? Not with the stock gauge I hope. Low pressure is fine below 3K (according to Toyota) but 4psi is lower than any GTE I've worked on... or GE for that matter. Toyota says 4.3psi or more is fine but in a healthy engine I don't think I've ever seen it lower than around 6 or 7 warm.

when it was first built it idled around 10 12 psi warm and would top around 40.After about 1k miles it would idle around 6-7psi and now it idles at 3-4 psi and is knocking pretty loud. You can't hear it under a load or at idle it makes noise from 1800-3000 rpm any higher or lower its silent.
does anyone sell a full kit to convert it to a full flow thermostat system? or am i gonna have to piece one together?
everything was checked before the engine was put together the crank is straight as well as the block it was checked on a machinists table and showed less than .001 difference anywhere.

I'm really thinking i put the ge pump in it hopefully the crank is fine this time. last time it happened i had one bearing with what loooked like a burnt spot but no missing material or scoring on the crank or bearings...

i was going to suggest a bent crank and/or out of spec mains. id have the block and crank checked for align straightness.

3 sets of bearings is pretty hefty for these, thats ruff though, sorry man, hope you figure it out soon.

Nope, no one makes a kit that I know of. It's easy though. 1/2" or -10AN hose, block adapter for remote mount oil filter, remote oil filter head, thermostat.... and whatever fittings you need. A sandwich plate with the ports on the side is far easier to work with than one where they come straight out... 90? fittings are more restrictive and depending on your IC piping size have very little clearance. I've been curious about how well a water based oil cooler setup would work on a mildly built 7M....

The GE pump isn't wonderful but people do get by with them in N/A-T setups without issue. I'd try eliminating the stock oil cooler as a suspect first (only temporarily). It's easy to check if it's the source of the problem: remove the filter, remove the cooler/filter adapter or whatever you want to call it, install a GE oil filter nipple and directly mount an oil filter... run engine. ;)

A burn spot, no scoring and no material lost? Wow, you caught that quick.... of course if I were dealing with the same engine I'd have very finely tuned hearing too. :D Well, you're having shit luck that's for sure, they're not my favorite platform but they're usually more reliable than what you've had to deal with. Are the knocks occurring in the same location? Is the engine level (not tipped on any given axis)?

ill try that.
the thing with the burnt spot was that it was just as loud then as it is now. it never gets louder it just makes the exact same sound the same volume but this time i have some flaking in my oil so i know its further gone.

anybody with experience hard mounting these know if it makes a difference? I've heard of people having issues with hard mounting certain engines because at a certain hertz they match the frequency the oil flows and it causes the oil surface tension to break... and miatas are known to chew rod bearings with aftermarket crank pulleys for the same reason. just a thought anyone running solid mounts?

the engine sits 2 degree tilted not enough to make any sort of difference. and the first time it was rod #3 ill know when i pull it apart if its the same rod.the first set of bearings were run for about 15 minutes and started making noise along with the head (there was a blocked passage in the head) i didn't pay attention to which bearing it was because I knew the head was the issue. everything mic'd good on the crank and i cleaned all the passages AGAIN got a new head cleaned it THOROUGHLY and put it all back together.

Solid mounts are miserable; If you want something more rigid look at the pre89 mounts. Harmonics breaking the surface tension isn't an issue anyone I know of has ever gone through in one of these engines (definitely not at power levels like you're seeing); You're grasping at a straw that isn't there. It's not worth the stress on the frame as it's not going to fix anything.

You sure there wasn't still crap from that blockage in the head stuck in there and waiting like a timebomb? You did miss it the first time. Could have been debris got stuck in the oil cooler too; Did you flush it?

the head was replaced with a different one and the engine was torn down 100% and all passages were cleaned and and bearings replaced.
the oil cooler and lines were replaced when the engine was torn down and head replaced (i just happened to get a new one at the same time).
and the mounts are solid not for rigidity but for the pure problem of clearance. the miata is a short car and the oil pan sits 1/8th inch off the steering rack and still doesn't clear the hood. I've gotten use to them and don't really notice the vibrations etc. any more. it just makes riding in any other car more comfortable lol it also has the stiffest springs available for the car along with coilovers setup for drift. i basically dd a race car. You gotta pay to roll in style (:

I'd still want mounts with SOME dampening there; Even if I had to build a mould and cast it myself.

Yeah, they're tiny... smaller than my MR-2. Fun rides these cars.

R u running a cheap aftermarket solid crank pulley they also wipe out the bearing on a 7m. Can the stock oil gauge even read 6 psi.

True about the pulley.... Your undampened clutch sends a nice shock down the line too; That's not going to do it by itself on a rebuilt engine, but your issues may be cumulative.

I just want to reemphasize, an undampened crank pulley and an unsprung clutch aren't going to keep killing a new engine, not unless something seriously out of balance. I agree that an oiling issue is most likely the primary culprit.

What oil are you running and how are you breaking the engine in? Are you running a stock flywheel and was it resurfaced?

stock ge flywheel brand new 3k ago and stock pulley that appears straight but its possible its out of balance i guess. the clutch was installed after the first set of bearings went out so i doubt thats it. plus the clutch is actually not all that harsh at all it only chatters if i drive really slow from a stop. other than that it feels like the sprung full face i had before. im pretty much 100% sure i have a ge pump in my engine. When i have the engine out this time i'm gonna have the crank machined or replaced and clean all of the oil passages again. i'll also replace the stock cooler setup with a thermostat full flow system and another set of piston squirters just to cut out ALL possibilities.

the engine was broke in on 10w30 conventional oil and the oil was changed at 300 then 1000 then 1500 miles running 100% stock boost and tune.

The pulley's easy to check even on the engine, but as you're taking it apart anyway that's academic.

Why'd you break it in with a variable viscosity oil?? Use a flat 40 weight.

How are you breaking it in too? The old fashioned 'baby it for 4K mi' or the nice and quick '50 mi aggro as hell' break in?

drove it easy for 1k and moderate for 500 before ever going WOT. I've always broke in engines with 10w30 and never had a problem before. I only use conventional and occasionally if the customer requests it I will use an additive. during tech school I was always told to breakin the engine with the oil your going to use (except for synthetic) because it will allow the bearings to wear as they need to for that oil. My instructor was a GM instructor is on the ASE board and wrote 2 of the ASE tests so I trusted what he said and never had an issue with it before. i've built 80-100 engines that make alot more power than mine does I'm just at a wall with this engine unless i drop a ton of cash into it which i'd prefer not to do. so like i said i'll see what i can do with the oil cooler and i'll replace all the squirters and oil pump as well as completely flush all the oil passages and lines while the engine is apart and see if it helps. if not it looks like i'm swapping something else in, probably 1uz.
thanks for all the suggestions i'm 100% certain its going to end up being the oil pump. I found the other pump and pulled the part# off it and its from a gte which means the pump in my engine is a ge pump. also the cooler could be stuck open. I'll take some pictures and let you know what comes of this the engine will be out and on a stand by wednesday.

Yeah, keep us posted. I'm quite curious because I don't know anyone who's had this much trouble rebuilding a 7M... bad luck sucks.

well just a little update. it was the same rod again but this time it completely spun the bearing and screwed the crank pretty bad the rod doesnt look too good either. I'm gonna call around and see how much some machine shops want to grind polish and campher the crank and true the rods and see what comes from it, otherwise it might be bye bye 7m hello 2j or 1uz. I love the 7m I love the 28 mpg in town and i LOOOOVVVE the torque and sound of it. I also love the unique-ness of the swap and that alot of people dont recognize the engine. it'll hurt to say godbye but if its gonna run me more than $500 for the machining bearings and oil pump then its just not cost effective to stay 7m /: i can pick up a 1uz or 2j for 500 with trans and ecm right away.

Dude there is a time and place for everything, buy a new block assembly and send this one to get recycled. My Firechicken did the same thing and no matter what the fellow did it was still fracked.

the block is fine. if it were the block it would have been all the rods or atleast a different rod than before. i'm gonna try and be able to rebuild again but if not the the cost of a jdm 7m is getting WAYYYY up there whereas a 2jz rb25 or 1uz is still reasonable. hell a jdm rb25 with trans ecm turbos wiring everything is only $1300 and can make almost 400 on stock turbos. so its just not smart to stay 7m if i need a new block assembly or if the cost goes over $500 because there is a 2jzvvt and several 1uz at the local junk yard for 335 with trans and ecm/wiring

have you had the crank mains checked for straightness or align bored? just because all of the rods arent going bad doesnt mean the block isnt out of alignment.

if its spinning bearings, id look at the oil passage ways in the crank and block as well. could be a blockage closer too the front galley and restrict oil to bearing #1. just a couple thoughts.

wish i lived around where you are. there isnt a 1uz, rb25 or 2jz of any kind around here for less than 2500.

Dude there is a time for everything, so tell me why you are having such problems. Me my time is worth a lot to me! Then you have the parts, etc. You would be better off recycling the short block and replacing it. Then again have you considered your driving?

the block is perfectly straight i checked it before it went together and just today when the crank was removed . it was rod #2 again im pretty sure that rod was out of round or something. its gonna run me 185 to have the crank and rods all redone. the block is gonna be flushed using brake clean at 120psi if theres anything in the block itll come out of it. YES my driving is very hard the car had 1200 miles on these bearings and maybe 300 of them are normal driving the rest is spirited driving around town, highway pulls, the strip,and drifting but even if the engine were driven at redline the entire 1200 miles the bearings should be able to handle it. the pump IS a 7mge pump and my cooler relief spring has a crack in it. i've found several things contributing to this problem. last time i just thought i was unlucky and got a bad bearing so i dropped the pan and put some bearings in it. this time i dropped the engine and put it on the stand so i'm finding the things to can't see until they come apart /: Oh well if it throws another rod then this block will go to the scrap bin I have the 185 plus parts now but i dont have the 335 plus for another swap at the moment.

all i know is....drifting and 7m's dont mix from wat ive heard. everything else is golden.

My suggestion for you is not to drift or race your daily. These cars were not designed to handle the stresses from these "activities". You should use your Supra as your daily and something more appropriate for your drifter, like a Fire Chicken. My old Fire Chicken with its 5.7 litter engine was a blast. A lot more torque than my Supra and the drive train that would not stop! The rest of the car was garbage but he could run! However now that I have "reformed", the Supra works fine for me :)

its not a supra i drive a miata with a 7m in it . i built it to handle the abuse ie coilovers swaybars, beefed diff, better clutch, tires and rims all that good stuff. but most of the time it is street driving. I get what your saying though you need a dd and a toy. but everything on my car has held up perfect besides the engine. this time it should be good though new oilpump crank and rods machined for the bearings rebuild the head and new cooler setup. we'll see

I'm sorry, but I've covered ALL OF THIS. You'd do well to pull your fingers out of your ears... Thousands of complete novices have rebuilt these engines without as much trouble using certain proven methods.... expert builder or not you still might be wise to try to learn from them. Honestly, you may feel you've been taught by God, but please do understand why I might not be remotely impressed.

The drifting issues come down to oil pan design. It's easily remedied by some added baffling, a scraper and running slightly more oil than spec. The "A" group of engines (both Turbo A and Group A) all ran a far superior pan which addressed these shortcomings.

i never said i don't make mistakes , actually quite the contrary I have admitted that i overlooked certain things. You have actually been very helpful with the info youve given me so idk exactly where your coming from with "pull my fingers out of my ears". I didnt ask any questions just answered others questions. I know whatever i overlooked was 100% my fault as I did ALL of the work myself ie oil pump, relief spring, and the #2 rod IS out of round. I honestly posted this asking a few simple questions and its turned into a big ordeal where I'm now being slightly insulted. I havent been rude even when answering questions that were answered in my first post and every time i've gotten a good response I've gone out and checked the engine right after. All i said is the mains are straight. the bearings PERFECT the rod bearings were also PERFECT with the exception of the #2 rod (I think it was out of round when it was originally installed) I probably was just in a hurry and measured a different rod twice. When the engine was being built/installed I was in a hurry because I only had this car for my dd and no other transportation, the stock engine had just blown up and I was still working a ways from my house. I realize pretty much ANYONE can rebuild an engine its not that much of a skill if you have the correct tools and specs. Thanks for the help/info but if i'm going to be ridiculed or told that i'm trying to impress someone i'll just go elsewhere with any questions. -__-

If you were taking most of the recommendations offered then it didn't come across well; You didn't appear to be listening, just dismissing or ignoring suggestions. <snip>

But do try not to take it too personally, I'm just a major dick sometimes... and sometimes I'm a colossal asshole (I answer to either). There's no need for you to leave, just maybe accept the possibility that there might be some old wisdom here that's worth listening to with a more welcoming attitude... Much of it's worked well for over 20 years with these engines.

EDIT: I still probably sounded like a dick there ^^^... not entirely the idea. Also, when you have it apart this time, don't forget to flush the oil cooler circuit... You said you didn't after the blockage incident.

I wasn't blowing off any suggestions just answering them. when asked if the crank was straight Yes it was checked and yes it was straight. Same with the block etc. Im not sure what CV means but i'm guessing its when I explained my instructors credentials?? If thats what it was i was explaining why I trust what i was taught. I mentioned being an engine builder to cut out unnecessary explanations or having obvious questions asked not to show off. Its kool though I didn't take it too personally just gets under my skin when people assume crap over the internet. If i wanted to just blow off all the suggestions I wouldn't have asked in the first place...


just fyi after typing out that i may have check one rod twice I realized I still have the rods from the engine that I didnt use. I looked at them closely and realized one of the caps had a G on it...... I put that on the rods i wanted to use and only wrote it on 6 rods -__- so I installed a known bad rod........ explains alot but all the other crap didnt help either I'm hating myself quite a bit right now. I guess I shouldve paid better attention and slowed down. oh well though you win some and you lose some looks like i lost this time. sending everything out to be machined monday. then onto making some cash for a new cooler setup and oilpump. looks like the moped will be getting alot of use for the next few weeks /:

Sorry, it came off to me as bravado... probably because you get so much of that here and in the automotive industry in general. It's not going to bother me any further. I just call them as I see them (and in the case of internet misinterpretations, apologize 30 minutes later :rofl: ).

CV = curriculum vitae; In essence a resume.

Don't discount the obvious things... those are usually what we find we've missed.

no hard feelings. I feel like a moron I can't believe I overlooked the fact I put in the wrong rod when I was in the engine 3 times -__- hopefully the crank is servicable and I can just put all this behind me. on another note it finally gives the old moped some run time and attention its getting "JDMED" out on friday lowered stretched and de-plastic it haha cant be normal ever :D

Dude, it happens to the best of us :) The important thing is to realize our mistakes and not repeat them. Do not hate yourself and please excuse my "teasing". Look at this as a "learning experience".

glad you found the problem! hopefully you can get it back together quick and up/running again. if you need another crank, ive got two 6m's that are good, one i just had polished the other day (it has been heat treated on the main and rods). the second is bone stock and needs a polish.

good luck with it, and if you need parts, lemme know