ca18det

[mitchsons2]

have ca18det big end went on no2 got secound hand motor 130000ks it also went after 50 ks re done only bottom end with new big end and mains bearing went again after 500ks what can be doin this

[float_6969]

Low oil pressure? Stretched rod bolts? What part of the world are you from?

[mitchsons2]

oil pressure is fine this has happened on two differant engines and one we put new mains and big ends in

[mitchsons2]

i am from new zealand motor is in a toyata ae85 race car

[Dan1200sss]

hey man what part of nz you in?

[float_6969]

Is it the same bearing every time? The UK guys seem to have a lot of problem with the big end bearings too, but we rarely hear about it on the JDM motors. I can't really find a difference between the two motors outside of the difference in the heads.

What kind of racing are you doing?

What weight oil are you using?

Do you have an oil cooler?

Are the rods stock?

What kind of revs does the motor see?

[mitchsons2]

Havn't checked the last one yet, but last two were both no 2.
Does a bit of everything, mainly circuit and car park cousres.
running castrol magnatec 15w-40.
No oil cooler
rods are stock
rev limiter is set at 7500rpm

[mitchsons2]

ashburton

[blownhemi]

I hope this is going to be a really stupid question, but did you measure your oil clearances, before the engine was put together? Main bore, conrod bore, but most importantly, crank journals?

I've read on many occasions on sxoc.co.uk, that XY spun a bearing, and then he just put the engine back together with new "shells", kind of expecting, that this is going to solve the problem, the problem having been probably just bad bearing shells.
Although I don't think that the UK guys with the Euro engine (or anyone else in Europe with the Euro engine for that matter) spin more bearings in CAs, as the US guys spin bearings in KAs, percentage-wise.

[mitchsons2]

yer check all bearing clearances all about two half thous we did not take engine apart the question is why on diffarnt engines doing the same thing

[D_Stirls]

Is there anything in your oil system that is not standard? Like are you running a remote filter etc.

How long are your track sessions?
Magnatec isn't the best oil to use in performance situations and the winter weight is a bit thick but that won't worry you once your up to temp. Here's nissan's suggested oil weights.



Also 2.5 thou is a bit big for a factory spec bottom end the factory tolerances are 0.8 > 1.9 thou but the limit is 4 thou so it is within that.
If you are pulling sustained high revs or putting out big numbers it doesn't hurt to go slightly bigger to reduce the bearing temps, provided you increase the oil supply (which is the problem with CA's as there are no bigger pumps available). I have set my mains up at 2.2 thou and i'm going to shim the relief valve to try to increase the flow.

[Dan1200sss]

Was that your 85 in the ashburton street sprints few weekends back? Yeah I reckon your just having bad luck with your bearings man due to a combination of used old motors that's bearings are allready half rooted, average oil, getting given a bit of s*** then them letting go. Iv had 4x ca18dets in my Datto now over the last few years.. 1st one was mint but had been record like 10-15thou kms before, but it Swallowed a TB butterfly screw and I pulled it down to forge it for fun. Then came across a freshly rebuilt ca long block with a few goodies but nothing special for a reasonable price but it only lasted just over 1000 kms before the bearings went! So carried on with my forged build then finally I found a $300 long block that I banged in there to use untill i had gathered everything I needed for the built motor. was an epic $300 motor until the sump bung got ripped clean out of it's threads and drained my oil while kaining it sideways up the gravel road. So that destroyed motor 3. Now Iv just run in my nice ca, done 2thousand kms on it with a Greddy T518z pumping a low 10psi until I get it to PAD for a dyno. Been giving it s*** and it loves it. So I suggest just having the bottomed rebuilt properly by atleast having the crank prepped properly (cleaned and grubbscrewed and peened in, balanced etc.) and atleast get ARP ROD bolts which is quite important.Alan at Cliff bond in ferry road and ERS did my botom end balancing and assembly. He's done a few of my mates turbo Nissan motors of varietys including a z22 hybrid. None of us have had a problem yet. Touch wood. I recommend full syn motul oil or atleast something like mobile one (grade depends on what your clearances etc end up being) also are you running an aftermarket tune ? Who tuned it may I ask?

[Dan1200sss]

Also What's your oil pressure at idle? Approx. and does it steadily increase to redline?

[mitchsons2]

yes it was my car in street sprints still not sure it is bad motors or something else is causeing it some have said it could be the clutch had the same clucth on all motors heavy duety with 5 pluk oil pressure 25 at idle and thats when its been running for along time and does go up to 80-90 at red line yes has after market tune bigger injectors air flow turbo was done before i got it meet the guy who built it at street sprints and he said it use to run 20psi and went like crazy not sure if i will rebuild thiking of putting a lexus v8 in it for some fun

[Dan1200sss]

oh sweet, how many psi were you running at the sprint? yeah i dunno how much truth there is to the clutch theory. iv been told it couldve been what killed my 1st rebuilt motor by a few people, by putting to much thrust on the crank or something along those lines..? hopefully some of the ca masters on here will have something to say on the subject of puk clutchs/mains damage. were you running the motor in still during the street sprint? oh yeah thats definitely allgood pressure, mines 30psi at idle when hot and have been told that thats dece as. oh yeah, the old put a lexas v8 in it trick lol if you cant get a nice bottom end to hold together your gonna be alot better off sticking with the ca as its far lighter and doesnt throw out the 85's balance like a big v8 will. plus think about how much power your going to get out of the v8 if its factory its not amazing and youll get over it and want more power, then realise oh its not turbo i cant just boost it up and tune it to get more power, instead youve got to buy 4x cams etc etc. or 8x forged pistons 8x forged rods etc. way more expensive to extract power from until you have bought all the goodies for it. your ca sounds like all it needs is to have that bottom end built right, run in properly! and then retuned with 20psi and you will be set.

[mitchsons2]

was only runing 5psi had done about 500ks runing in then run 9psi at a motakna last week end when it went

[float_6969]

Your oil pressure values sound good, and the weight of oil you're using sounds good as well. IDK about your brand of oil for racing applications, but it shouldn't be an issue. What first struck me about what you've said is that the #2 main is the bearing that has let go on you. It doesn't show this anywhere in the FSM, but I know this motor and I can tell you that the #2 bearing is the first bearing to get oil from the galleys. What kind of filter are you using? I ask because I'm rebuilding my motor right now because of an oil filter failure and the #2 main bearing took the brunt of the damage from the oil filter debris. If the filter and oil combination have been the same with all of the motors, you might try changing that combination around.

Another thing to remember is that there is a presssure bypass valve behind the oil filter mount in the block. If the oil pressure gets too high, it will open, recirculating unfilterd oil back into the motor. I don't know the pressure that this valve opens at, but if you're reaching that opening pressure, this could be causing your problems as well.

[boost_boy]

It is time to get those blocks align-bored and possibly have the cranks inspected. If your oil pressure is good, then either your journals are out of round or the crankshaft bores are distorted.

[mitchsons2]

yer thats what i would do if re building but remember this has happened to three differant engines

[float_6969]

2 motors, the 2nd one was rebuilt. There has to be a common denominator between all of these engines that we're not hearing about.

[mitchsons2]

the olny things that have not been changed are head and clutch

[D_Stirls]

So i guessing the you don't have a remote filter setup? (might have missed your answer)

[mitchsons2]

no just standed oil filter on motor

[D_Stirls]

Z145a filter?

[curo72]

Have you had your head hot tanked between motors? Cleaned out any oil lines?

[boost_boy]

Are you using the same flywheel and clutch set-up on each of these motors? If so, then there's your culprit. You may want to inspect the thrust washers on the main bearing. A poorly designed/built performance clutch (especially unsprung) will put alot of stress on thrust washers which will ultimately cause premature bearing failure.

[dash]

the olny things that have not been changed are head and clutch

oil drainback/crankcase breathing problems kill most CA18s..... especially when beating on them
might be transferring the same problem to all your motors ?