|12-19-2012 11:29 AM|
What kind of oil do u recomend for break in and what kind after break in? I dont want to use newer oils even if I have to order my oil online. Every oil I use looks burnt after a few 100 miles and always smells burnt. I want to use thicker oil than recomended for my truck which is 10w30. I want good added protection in a oil I use.
This is off subject but what is a ball park price on line honeing a 350
|12-19-2012 11:13 AM|
|12-17-2012 07:59 PM|
|12-17-2012 07:56 PM|
|ChevroletSS||Thanks for the input|
|12-17-2012 12:34 PM|
|12-15-2012 07:09 AM|
There IS going to be some metal worn off during the process of ring and cam break in. Fot that reason I believe seeing a film of magnetic particles as well as a metallic hue to the oil after the cam break in of a flat tappet engine the norm.
As for the rest of it, if that's your experience then so be it. But it is not going to be something that everyone- including myself- will agree to all of.
|12-15-2012 01:54 AM|
Your bearings are worn out. Make sure that the wear is even all across the surface. If it is not, then you should line bore/hone the block and straighten the crank. Don't do this yourself. Crank straightening is an art. Mike the crank to be sure it is still round, then buy new bearings to provide the proper clearance. The more clearance you run, the lower your oil pressure will be. I like to see oil pressure in my V-8 Vega (350 four bolt main early LT-1), so I use .001" on the rods and .0015" on the mains. It carries 40 psi at hot idle on a 100 degree day with the air on full blast. It also revs to 8,000 rpm. My 327 small journal ran for 300,000 miles and still didn't get down to the copper. I give the credit to Valvoline 40w Racing oil and STP. The STP stays on the bearing surface when you shut the engine off, while the hot oil drips back into the pan. The next time you start up, the STP gives some lubrication until the oil pump can start delivering oil again. I also suggest a magnetic drain plug so that you can check to see if you are having undue engine wear. After break-in, your engine should not have ANY hair (metal particles) on the drain plug. if it does, then your oil is not doing its job. I recommend NOT using Pennsylvania based oils because they have a high ash content and cause excess wear. Paraffin based oils are much better (Valvoline, Havoline, etc.). Valvoline 40w Racing oil is the Army's first choice for their aircraft piston engines. They also suggest the STP "if you can find it". Stay away from anything purple.
|12-14-2012 02:52 PM|
JUST REMEMBER TO GO BY THE PISTON MANUFACTURES SPECS (they may differ Quite a bit)!!!
I'll add a little more
"Cam ground piston Definition from Science & Technology Dictionaries & Glossaries
Dictionary of Automotive Terms
cam-ground piston: .
A piston with a skirt that is ground slightly egg-shaped or oval-shaped. The widest diameter of the skirt is at right angles to the piston-pin axis. When it is heated, it becomes round. The design allows for a closer fit in the cylinder so that there is a reduction of blowby gas, cylinder scuffing, and piston slap ."
Measuring the piston
Using a micrometer, measure the piston skirt across the thrust faces as shown in Figure 7.7. In most cases, the measurement is taken at a point which is approximately one-third of the skirt height. This is the nominal diameter of the piston and should be the greatest dimension.
Other measurements can be taken as a check and to make sure that the piston has not collapsed. A collapsed piston will have a reduced diameter at the lower end of the skirt.
The engine manufacturer’s service manual should be consulted for piston dimensions and clearances. It will also have information on how to measure the piston. Some pistons are cam-ground, some have a tapered skirt and some are slightly barrel-shaped. All pistons are not measured in the same way.
Figure 7.8 is an example of piston measurement. It shows the places on a piston where measurements would be taken. These are as follows:
BB is the nominal piston diameter
AA is the reduced diameter after cam grinding
CC is the diameter at the top of the skirt
DD is the diameter at the bottom of the skirt
EE is the reduced diameter at the lands.
The pics posted bellow Sorry
All modern cam-ground pistons, measured for clearance 90 degrees (right angled) to the wrist pin. and measured for clearance this way.
Thus, if the block is bored exactly .030" oversize, the clearance will be what the manufacturer intended, usually around .004" to .005" at a point perpendicular to the wrist pin.
Man!!! I sent this early I hit the send again instead of the preview
LOLhttp://www.hotrodders.com/forum/attachment.php?attachmentid=69805&stc=1&d=13555222 http://www.hotrodders.com/forum/attachment.php?attachmentid=69809&stc=1&d=13555235 4268
|12-14-2012 05:22 AM|
Clearances for forged aluminum pistons:
SAE 4032 aluminum ...high performance street, .002" - .0035"
SAE 2618 aluminum... competition, boosted, scuffs easily, .004" - .0065"
If your engine has 400 - 450 HP, driven on the street and want durability, use pistons that are made of SAE 4032 aluminum. Engine with more than 450 HP should use pistons made of SAE 2618 aluminum. SAE 2618 aluminum is low silicon and is softer and need to checked for wear, scuffing and are replaced more often.
|12-13-2012 05:42 PM|
|12-13-2012 04:15 PM|
|ChevroletSS||My machinist could of told me that. At least Ill have a fresh block when I get it for free and Ill have to just pay to get the final hone. Thanks for that article jester. Thanks everyone for the help. Ill scratch the idea of doing the other engine myself. Ill save it for a big project|
|12-13-2012 03:00 PM|
"What do you mean by piston to bore clearence. Is that the gap inbetween the two."
Aluminum expands about 1.7 times the rate of cast iron so there has to be room for that expansion. Rather then me typing this I'll just add this attachment! Remember: Different manufacturers and piston types(forged, cast,ETC,ETC, have different recommended clearances ) dont just open a repair manual and think that's correct!!!! you should always have the pistons before the block gets bored..That way the machine shop can do the final hone to get the exact piston clearance you need.. Most pistons you measure the skirts with a micrometer 90deg from the pin, just below the oil rings.
Measure the cylinder bore and subtract to get the clearance.
The piston is larger at the bottom of the skirt and smaller at the compression rings to allow for expansion of the piston dome. Pistons are also "cam-ground" (egg shaped, not perfectly round) as well so measuring somewhere other than the piston mfgr's. recommendations will give you an inaccurate number.
This is one way to check!
|12-13-2012 05:42 AM|
|ChevroletSS||Hey Im just saying what I said I wanted done before I took the stuff off my truck. I didnt have caps and he had a **** load so he gave me some and said he would line hone it. The blocks I had were all 305s and he wanted the blocks. If they were 350 or bigger I would of kept every one of them. Actually I did keep one 305 to replace my 350 in my truck. As far as the crank for the motor I was going with new everything. Were starting to get off track some. The block Cobalt327, Hcompton and myself were talking about in the last two posts is not the one I took the bearings out of. Also I would never reuse main bearings. The cylinder walls actually look like they were just redone. Its crazy to me how good this block looks. Well I did baby it when it was in the truck but still its beautiful. What do you mean by piston to bore clearence. Is that the gap inbetween the two. Im gonna go take some pics of my 94 chevy block|
|12-13-2012 05:31 AM|
New parts in machined block.
To this post, I would have no problem putting in new parts the sizes the machienest stated he did work for. The coviot is make sure his work is correct and sizes he states are correct.
cas in point had work domne on one of my 400SBCs and crank was stated as a 10-10 under.
He gave me bearings for a 10-10 crank, and I did not check.
After assembeling 3 Main caps (Torque could not spin crank. Checked and hasd 20-20 crank. So if the machine work is correctly sized, makes no difference if you put different parts in as long as sized for that motor.
Always check clearences on assembely.
|12-13-2012 05:25 AM|
This could go on forever.
I am responding as I see it.
The question to me was would I have the block line bored. My experiences.
Racing ? Yes to correct any alignment problems and eliminate friction.
Probibly not if indeed this engine has 150,000 miles. If block has this much wear on bearings it probibly has ridges in cylinder the size of the grand cannon. Id insytall new bearings, that fit crank whatever the undersize may be as long as crank is round and true and even.
Bore block for new pistons.
normal other replacement parts that would be worn out. CAm Timing chain, gears, Head rebuild.
The indecater to me to line hone block is if you spun a main bearing. Line hone would be mandentory on any bearing spin.
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