UK guys,big end rattle?

[float_6969]

Alright UK guys here is what's going on. I have an oil leak at the headgasket on the exhaust side on the rear corner of the head. My lifters are noisy and the sound comes and goes. After doing some reading it seems that big end problems are common on the CA over in the UK. I hadn't ever considered having problems with the big ends since it's a newly rebuilt motor, but I thought it wouldn't hurt to check.

The generally accepted procedure is to rev the motor to 3K and then let off of the throttle and let it come back down. If there is a rattle between 3-2K rpm, it's be big ends.

I tried this and didn't get a rattle on engine deceleration, but I have a lightweight flywheel and it takes maybe 1/4 of a second to go from 3K - 2K.

Here is my concern, I DO have a bit of a metallic rattle right around 2300-2700 rpm. It only does it when free revving the motor in neutral, and only when maintaining that RPM. When the motor is increasing in RPM or decreasing in RPM, the noise isn't present?

Is this still a top end noise associated with my potential lack of oil pressure in the head from the oil leak, or do I need to drop the oil pan and check the rod bearings?

I've heard rod knock in other motors before and this doesn't sound nearly that bad, but like other motors, it only happens in a very specific RPM range.

[Chris859]

I'm not a UK guy, and I'm sure you already thought of this as well - But what about the possibility of it being piston slap from excessive piston to bore clearance? It would really suck to have to pull the engine apart again. Just some food for thought as well....

[float_6969]

It does have forged pistons and when I just did that test, the motor was relatively cold. I didn't do the boring myself, but I do know the shop had the pistons there and the spec sheet from CP as to what the clearance was supposed to be, so I would be surprised if that is the issue.

I've got another S13 w/a KA w/issue's I'm trying to fix right now. When I get that all sorted out, I'm going to swap motors and sell the current chassis. I may tear the CA back down and check out the motor and see how it's looking inside.

[sideways danny]

I'd suggest you get the engine fully warm and have another listen, I'd be very surprised if you had no piston rattle when it's cold, almost all forged pistons have to expand quite a lot.

big ends starting to go normally sounds a little like "duga duga dug" when doing the overrun test you've already done

did you fit a brand new oil pump when you built the engine?

[float_6969]

Alright, I let it warm up this time and I believe the sound it basically gone. If it's there I can't hear it over the lifters.

It does have a brand new oil pump, but my oil pressure is lower than what the FSM rates it at. I'm currently running Mobile 1 full syn 0-40w. I'm running a very small battery right now and it gets pretty cold here in KS. I believe that is partially contributing to my low oil pressure. I think it mostly has to do with the HG leaking oil. I'm guessing that I'm not getting good enough oil pressure to the head to keep the lifters pumped up. When the motor and oil is cold and the oil is thick and viscous, they'll stay pumped up and don't make any noise. Once the motors warms up, they do it almost constantly.

I've got all the parts, it's just cold as heck here and I'm not looking forward to draining the coolant to change the HG.

[r34 gtr]

man, sounds like our engines share a common problem. mine leaks oil at exactly the same spot. i get some rod knock/slap when the engine is cold and/or idling, but it runs like a champ (not really, but it isnt the engine's fault) so i am not concerned. if the bearings go, they go. just mill the crank and keep on trucking.

[float_6969]

Yea, after realizing that it dissapears when the motor is warmed up, it prob is the forged pistons.

I'm still hoping that the oil leak is the cause of the noisy lifters

[r34 gtr]

ive got lower than spec oil pressure too, but its really consistant and its never been a problem. maybe the leak at the back of the head causes that too. i know the engine is solid outside of that. well, aside from the noise.

[float_6969]

Mines' the same way. The oil pressure is constant. And it's actually at spec at idle, it's just to low at the 3K level, which would be consistent with a leak.

[boost_boy]

Damn Ryan, sounds like it could very well be your rod bearings. I base this off your original post and past experiences with the CA. Cheapy oil pumps are always suspect to me. I don't know if you got one, but I've come across a couple of bad pumps in the past and it has cost me dearly. Fortunately, the pump I use now is a beast and even at 800rpm, it sits at or around 30psi and when I jam the pedal after warm-up it shoots up realy fast to around 80psi. The cold starts are at 60psi at idle and if you blip the throttle, it goes to a little over 100psi before it warms-up settles down.

I would just start unplugging spark plugs wires to take the load off an individual cylinder to determine what it really is. IMHO, it takes an act of stupidity or a failed oil pump to trash the main bearings. The rods are usually the first to get smoked, so if after you pull the wires and you still here the noise, start with the rods and the bearings.

Lastly, if you slightly melt or trash a ringland from detonation or leaning out, then you will more than likely hear some strange noise inside the engine. Call me if you wanna rap more about it. I'm home until the 28th and then I have to return for the spanish program (Sucks). But at least I have a new job, gun, badge, bulletproof vest, blah, blah....... .

Dee

[BACARDI_DWB]

dude why are you runing synthetic motor oil in it already??? you should run a regular motor oil to break it in. cause synthetic will not allow for any breaking in wear marks. do a google search and it will reveal more but any time you break in an engine you always use the standard engine oil NOT synthetic till at least 3000-5000 miles

[BACARDI_DWB]

http://p2library.nfesc.navy.mi....html

"Synthetic motor oils are blends of synthesized hydrocarbon fluids (SHFs) and esters derived from petrochemicals, and are manufactured by combining the various organic chemicals. They can be used in place of conventional motor oil......However, the lower friction resulting from the use of synthetic lubricants makes them unsuitable for break-in."

[BACARDI_DWB]

I HIGHLY suggest running a heavyt weight oil 20w50 to help set the rings for the first 2000 miles AT A MINIMUM. Synthetic is a great thing to use when you have a broken in motor. during the breakin procedure, lots of imperfections in metals and shavings will be found in the oil. that is completely normal. hell if you didn't have metal in the oil i would be scared. but with a Synthetic oil there is not enough friction in the oil to break down the imperfections and let the motor properly break in. trying to find some more links for ya

http://www.trustmymechanic.com/motor-oil-bible.pdfcheck this out on page 115

[Swedish Mike]

That´s correct but I don´t think the oil causes problems like this.I´ve used both synthetic and mineral oil for break in and both works fine, only reason I´ve used mineral last few years is becuase it´s cheaper and i change oil often after a rebuild.I use 5w50 Mobil 1 or 10w60 Castrol in the CA´s, Castrol in the summer engines.

I´ve had oil leaks and later on compression leaks at non straight engine blocks but not after rebuilds and regrinded surfaces. Strange one.

Another thing that can cause lower oil pressure is bad bearings, too much gap will lower the pressure.One of the first warnings before the knock sound.

This is are hard one, I really hope you hear piston sounds and not bearings, it´s pretty loud in iron block engines but will get better when the summer heat returns.

[r34 gtr]

when i broke my engine in, i used dinosaur oil and freaking stood on it immediately after firing it up. as a result its kinda loose but i feel it runs like an absolute champ when warm. sure you get some bottom end noise and it leaks a lot of oil, but its not gonna be giving out on me.

ryan, get that head milled true. see if it fixes anything. if not it isnt exactly hard to change out the bearings. i did rods and mains on a jeep i-6 with the crank in the car. just use a soft piece of metal to tap the bearings into place. like aluminum, it wont scratch the journals. shouldnt cost you more than about $100 all said and done, and it shouldnt take but an afternoon. i know youve got the skills to pay the bills, so to speak.

[float_6969]

Damn Ryan, sounds like it could very well be your rod bearings. I base this off your original post and past experiences with the CA. Cheapy oil pumps are always suspect to me. I don't know if you got one, but I've come across a couple of bad pumps in the past and it has cost me dearly. Fortunately, the pump I use now is a beast and even at 800rpm, it sits at or around 30psi and when I jam the pedal after warm-up it shoots up realy fast to around 80psi. The cold starts are at 60psi at idle and if you blip the throttle, it goes to a little over 100psi before it warms-up settles down.

I would just start unplugging spark plugs wires to take the load off an individual cylinder to determine what it really is. IMHO, it takes an act of stupidity or a failed oil pump to trash the main bearings. The rods are usually the first to get smoked, so if after you pull the wires and you still here the noise, start with the rods and the bearings.

Lastly, if you slightly melt or trash a ringland from detonation or leaning out, then you will more than likely hear some strange noise inside the engine. Call me if you wanna rap more about it. I'm home until the 28th and then I have to return for the spanish program (Sucks). But at least I have a new job, gun, badge, bulletproof vest, blah, blah....... .

Dee

IDK, I'll drop the pan in the next few weeks and see. It hadn't change or gotten different and unless the CA is vastly different, I've heard rod knock before and this doesn't sound like that.

It wasn't a cheap oil pump, it was new from Nissan before they discontinued them.

As I said, I think the sound disappears once it warms up. The damn lifters make so much noise though it's hard to tell. I've really got to get that HG fixed so it's not leaking oil.

The ringlands are a possibility. They are forged, but this engine was my first tuning experience, it's high compression, and it was street tuned.

dude why are you runing synthetic motor oil in it already??? you should run a regular motor oil to break it in. cause synthetic will not allow for any breaking in wear marks. do a google search and it will reveal more but any time you break in an engine you always use the standard engine oil NOT synthetic till at least 3000-5000 miles

LOL, comeon buddy, I'm not a total newb! This motors got over 30K miles on it! It never saw a drop of synthetic until it had 2 oil changes under it's belt (6K miles).

when i broke my engine in, i used dinosaur oil and freaking stood on it immediately after firing it up. as a result its kinda loose but i feel it runs like an absolute champ when warm. sure you get some bottom end noise and it leaks a lot of oil, but its not gonna be giving out on me.

ryan, get that head milled true. see if it fixes anything. if not it isnt exactly hard to change out the bearings. i did rods and mains on a jeep i-6 with the crank in the car. just use a soft piece of metal to tap the bearings into place. like aluminum, it wont scratch the journals. shouldnt cost you more than about $100 all said and done, and it shouldnt take but an afternoon. i know youve got the skills to pay the bills, so to speak.

I just recently bought another S13. I'm fixing the KA in it right now and it should be up and running in the next week. I'm gonna drive it for a couple of weeks to make sure I got all the bugs worked out, then swap the tag and insurance over, and pull the CA out of the current S13 and get the HG changed, check the bearings, rings, pistions, ect. And then swap the motors and sell this one.

I'm getting old and I want an interior....and a radio....and cruise control....and A/C.

[BACARDI_DWB]

phew. you had me scared. i thought it was upon initial startup. good onya

[tyrannix]

I'm getting old and I want an interior....and a radio....and cruise control....and A/C.

seeing the light, eh?

stripped interiors arent for street cars... the only thing i dont have for my silvia is cruise control.... and i may add that in with the old us stuff and megasquirt later on with the GPIO board... but i hardly ever use cruise control even on cars that have it (except the cressida, i plan on using that alot more, especially after the new engine)

after i clean up some more of my packed junk, i may have most of the digital climate stuff (in addition to teh stuff i got from you, i think i had most of it from my silvia, just cant find it) if you want it, let me know

you swapping the fixed headlights over to the new one too?

CJ

[float_6969]

I'm thinking about doing the digital climate control again. I liked it before, and with the new chassis having the digital speedo and HUD, it would be a pretty cool combo.

As for the silvia conversion, I'm going to leave it on the car. The headlight brackets are easy to come by as are the headlights, and side lights. As for the rest of it, I think I'm going to get a Chargespeed front end conversion this time around. The price difference isn't all that much actually and should go well with the rear widebody panels I'm going to run. The rear quarters have some rust and one is banged up pretty well, and for the price, it's way easier to run a widebody than to fix it with OEM panels. Plus it'll let me run some nice wide tires!