Thanks to a 15 minute phone call from Terry (star turbo talon) said that my knocking noise was probably piston slap. My mechanic came over, we let fired her up, and the noise was there. He said he thinks its piston slap also. Before it ran for liek 20 seconds max. i let it run for about 15 minutes to get to normal operating temp and it quieted down some. It sounds liek a diesel kind of. Is that normal for lower compressions on the 420a. I know Terry told me some people get it and some dont. H e said grain's car sounds liek a diesel, so I am guessing I am ready to start driving her, right...?

I also went with the suggestions of using the largest disk, 2.7" ring and darker spring in my sfmu. I would have to say, it idles like stock WITHOUT the s-afc! I am going to install the afc still just for monitoring and fine tuning. My idle pressure is at 20psi and I am seeing about 22psi oil pressure at normal temp and 16-18psi vac at idle. I have a SMALL vac leak somewhere, that I will find this weekend.

so, how do my numbers look here and is the piston slap okay? once being broken in, will the slap go away or what?
i just read the paper that came with the JE pistons and it says not to use additives or synthetic oil obviously to set the rings because it will take longer. right now i have a bottle of thick STP oil treatment in there with soem syntethic syntec 10-30 oil so i will be swapping to regular 10-30 oil this weekend.
other than that, how are we looking here fell's!?


thanks again terry, boosted eclipse, and everyone else for your help and suggestions. i am sure my previous thread will be a HUGE help for others who search and find it.

Originally posted by eclipse982nrRST
Thanks to a 15 minute phone call from Terry (star turbo talon) said that my knocking noise was probably piston slap.

Terry is a good guy. Helped me out a number of times. :thumbsup

Originally posted by eclipse982nrRST
i let it run for about 15 minutes to get to normal operating temp and it quieted down some. It sounds liek a diesel kind of. Is that normal for lower compressions on the 420a

Forged pistons are known to "slap" and sound somewhat diesel-like until they warm up. I'm pretty sure I've heard that JEs slap more than most. It has to do with the metal expanding until they are thoroughly heated up. I don't think it has anything to do with the CR.

Originally posted by eclipse982nrRST
i just read the paper that came with the JE pistons and it says not to use additives or synthetic oil obviously to set the rings because it will take longer. right now i have a bottle of thick STP oil treatment in there with soem syntethic syntec 10-30 oil so i will be swapping to regular 10-30 oil this weekend.

Drain that treated shit right away. Use the cheapest conventional oil you can get. Drain it after 100 miles. Then go 500 miles and change (again, conventional). Then go 1000 miles and do the same. I think after about 2000 miles you should be broken in enough to go over to the synthetic. You want to use conventional oil during the break in, as synthetic is too slippery to to allow the rings to seat right.

Originally posted by DR1665

Originally posted by eclipse982nrRST Thanks to a 15 minute phone call from Terry (star turbo talon) said that my knocking noise was probably piston slap.

Terry is a good guy. Helped me out a number of times. :thumbsup

Originally posted by eclipse982nrRST i let it run for about 15 minutes to get to normal operating temp and it quieted down some. It sounds liek a diesel kind of. Is that normal for lower compressions on the 420a

Forged pistons are known to "slap" and sound somewhat diesel-like until they warm up. I'm pretty sure I've heard that JEs slap more than most. It has to do with the metal expanding until they are thoroughly heated up. I don't think it has anything to do with the CR.

Originally posted by eclipse982nrRST i just read the paper that came with the JE pistons and it says not to use additives or synthetic oil obviously to set the rings because it will take longer. right now i have a bottle of thick STP oil treatment in there with soem syntethic syntec 10-30 oil so i will be swapping to regular 10-30 oil this weekend.

Drain that treated shit right away. Use the cheapest conventional oil you can get. Drain it after 100 miles. Then go 500 miles and change (again, conventional). Then go 1000 miles and do the same. I think after about 2000 miles you should be broken in enough to go over to the synthetic. You want to use conventional oil during the break in, as synthetic is too slippery to to allow the rings to seat right.

I have heard the same about using shit oil. However, BMW's Corvettes and many other cars run synthetic right out of the factory. I dont see why it would be a problem. However I am going to run regular 20w40 for my first start let it get to temp/cool. Drain the oil put in some 5w30 mobil 1, start it up let it get to temp/cool down and then have at it! This is what Forward Motion recomends.



best time so far 14.3 @ 101.1mph(no traction)
www.cnnmotorsports.com

I have been overly anal about my engine's first 1000 miles. Oil changes after first 20 minutes of idling, 100 miles, 250 miles, 500 miles, and then at 750 miles. I'll change it again at 1000 (I'm at 850 miles right now) and then return to the every 3000 mile routine.

Probably overkill, but worth the peace of mind to me.

Tony

Any time Mike. I agree with the info posted above regarding oils. i have always been told be machinists to break in with conventional oil and not synthetic. Reason being is the parts need to wear together. with conventional oil this will happen faster. with all the additives the synthetic has, friction is reduced therefore makign the break in process to take longer.

Now i would avoid using additives like STP that are extremely thick. Many of the additives that are out there can plug up small oil orifices in the motor.

Terry

Originally posted by Star Turbo Talon
Many of the additives that are out there can plug up small oil orifices in the motor. Terry

and most of these so called "additives" have a bunch of crap in them that wrecks the viscosity of the oil.

read this on additives. Good read.

http://www.chris-longhurst.com/carbibles/index.html?menu.html&additives.html


and this is also usefull information

http://www.chris-longhurst.com/carbibles/index.html?menu.html&engineoil_bible.html

For initial start, we've always used straight 30 weight. My dad's had his own shop since I was born, he's an ASE Master Technician, and he's built several motors, including my brother's 9 sec mustang, so I tend to listen when he talks about motors.

I used the straight 30 weight for the initial start in my eclipse, ran it for about 30 mins, then drained it and went with regular 10w30 and did the break-in of WOT to a certain RPM, then coasting, then WOT, etc, etc. Back to the shop to change it again. Put 10w30 back in it, change at 500, then again at 500, and again at 1000, and then used synthetic 10-30 and back to regular 3k miles.

That STP stuff is more for high mileage cars, and it also works like that Lucas oil stuff that makes it super sticky so it stays put better. I think it's too thick for our lifters, though.

What is your skirt clearance? You shouldn't have slap so bad that it scares you into turning off the engine.

piston slap is sexy aint it? when my motor is cold it just sounds reallll angry, lol :thumbsup

i use 10w40 conventional valvoline for all my new motors and have had solid compression every single time after its broke in, so if the shoe fits...wear it :thumbsup

edit: another cool thing i did on my most recent motor was used a fiber optic camera probe thing and unscrewed the spark plug and slid it down in there to observe the cross hatching and wearing on the cylinder walls, at first theyre nice and machined and then gradually that wears away and its nice and smooth...its really interesting to see how it wears after every couple hundred miles. i got the idea from an O.G race engine builder here in san clemente.

having used both JE and CP's in the past I can say that the JE's do have a tendancy to make a little more noise. It sounds like you are good to go.

--------------------------------------
know me as santiago
boosted 420a and ej2o..(my 2liter v8 eaters)

i think i should be good. just sonds liek a diesel, thats all :) after it warmed up, the noise went away some, it was still there, but not as loud. to whom said it should be too loud to scare me to start it, it scared me the first time, cuz i thought it was rod knock, thats all. how do i post a video on here? like transfer it?

The piston slap is probably normal for forged.

DO NOT USE SYNTHETICS OR ADDITIVES FOR THE FIRST 2000 miles!!

Use straight 30W no additives. That's all we ever used for break in purposes.
MB

My dad has had his own machine shop for long as i can remember, and we have rebuilt tons of engines, and probably over 20-25 420A's alone. no matter what kinda forged piston you use, you will get piston slap. if the clearances arent "excessive", its actually a good thing, cause it shows you are allowing room for the forged units to expand as they heat...the flip side of that being not enough clearance on a forged rebuilt motor, and when it warms up....the pistons seize. piston slap and rod knock, to me, sound nothing alike. rod knock will get worse as the engine warms, and louded as you accelerate. slap will do the opposite.


1997 Silver RS
Built
T3/T4 BB Turbo
20psi
Most current 1/8th mile time: 8.1@93mph 2.015 60'
1996 Black Supra TT
2004 Silver Snake

ya it gets quiter when it warms up deff. its still there, but not too loud. and when i give it throttle, it almost goes away. i remember what my rod knock sounds like from last year, dont think this is the case! i have a video clip of it if i can just figure out how to get it on my computer and host it!

Just had my engine rebuilt and have the same piston slap (worried me at first as well). Louder @ startup then when it warms up the slap quiets. I've been letting it idle and warm up to normal operating temp before driving, then just taking it out for a short drive once every week or so. While driving the slap is pretty much non-existent. I've been doing the previously mentioned now for a few months as the winter weather makes it hard to get out and the slap is getting progressively quieter and quieter. Used 5w-30 oil initially and will change it after first 500-650 miles. Then again after about 1000 miles.

Afew Questions:
Would some better tuning eliminate the slap further?
How long after rebuilding an engine is a good time to introduce boost?
When boosting is synthetic oil recommended w/ 92 Octane?

its annoying. lol i have even driven my car yet becuz of the weather
:(

im gonna get a video clip up of the noise once talonguy2005 gets it done for me!

sorry man, ill get it done, just the camera was being mean, ill have it done asap. sorry for the wait.

I've had the same problem but my noise went away after about 300 miles and my machinist said that the noise was the forged pistons and unseated rings.once the rings fully seated the noise gradually went away.

Originally posted by DR1665

Originally posted by eclipse982nrRST Thanks to a 15 minute phone call from Terry (star turbo talon) said that my knocking noise was probably piston slap.

Terry is a good guy. Helped me out a number of times. :thumbsup

Originally posted by eclipse982nrRST i let it run for about 15 minutes to get to normal operating temp and it quieted down some. It sounds liek a diesel kind of. Is that normal for lower compressions on the 420a

Forged pistons are known to "slap" and sound somewhat diesel-like until they warm up. I'm pretty sure I've heard that JEs slap more than most. It has to do with the metal expanding until they are thoroughly heated up. I don't think it has anything to do with the CR.

Originally posted by eclipse982nrRST i just read the paper that came with the JE pistons and it says not to use additives or synthetic oil obviously to set the rings because it will take longer. right now i have a bottle of thick STP oil treatment in there with soem syntethic syntec 10-30 oil so i will be swapping to regular 10-30 oil this weekend.

Drain that treated shit right away. Use the cheapest conventional oil you can get. Drain it after 100 miles. Then go 500 miles and change (again, conventional). Then go 1000 miles and do the same. I think after about 2000 miles you should be broken in enough to go over to the synthetic. You want to use conventional oil during the break in, as synthetic is too slippery to to allow the rings to seat right.

Terry is the man with the answers on here! He knows the 420a inside out. Helped me out as well.