Would it be a good idea to pull one out by using a bolt through chains on the headbolts, 1 in each corner? the head is already out. Usually the others I've pulled with the heads on I used bolts on the tranny bolt holes and the big hole on drivers side near front of engine. Just curious...

Argh, I need some encouragment to stay with a 225... this will be the third time I need to pull the engine. Originally I was replacing a seized motor, then the second wasn't rebuilt right, was very stiff... now this one is making a loud clunking noise, cause is yet to be determined but I know problem is from pistons down. If this one needs another full rebuild (paid $1400 for the last one to be rebuilt) I will seriously consider grabbing a junkyard smallblock and pay the same to have it rebuilt. My brother rebuilt the motor and said he put 1400 into it (rebuilt to stock specs) but when we put it in the crank was very stiff and the starter wouldn't move it a full revolution. We pulled it out and couldn't figure it out... so we took it to an engine rebuilder and he disassembeld and put it back together for $300, said we had one of the crank bearings backwards. So we put that engine back in, and 500 miles, heck probably less, later, I get this loud clunking.

Sounds like you need to kick your brother's butt.

If the head is already off, the head bolt holes will work fine.

Sounds like you need to kick the rebuilder's butt too.

Clunking noise isn't a loose converter bolt is it?

_________________
Official Cookie and Mater Tormentor.

Oh don't worry, I was going to pay him the 1400 but he ate the cost and I got a free engine when I had to pull it out the first time.

Hmm, I'll have to check the torque converter bolts before I gank the engine. But I don't suspect that because when I had the head on it seemed to be making the clunk every other crank revolution, makes me want to think something is funky with the cam. My curiosity piqued because when I pulled the head it didn't make that noise any more, but the head/valves etc look fine. Still could be a bottom end problem because taking head off sure does lower compression (I did a compression test and all cylinders hit 150psi, and it still was making said clunking during the test and no plugs in the engine, but still no head is less compression then head and no plugs....) All valves were moving fine so timing chain is legit, and I just pulled all the lifters and they look fine.

It sure sounds like the rod bearing clearances were not set right. Were the con rods reconditioned / resized?
Once the pan is off, you can feel for the side clearance on the rod bearings, when you do this, give them a little twist. You can find a loose (or tight) one pretty fast if you know what to look / feel for.

BTW, setting-up bearing clearances is not "rocket science" and it needs to be done right or the bearings do not last long, no matter what type of engine it is. Truth is that a SL6 is one of the most forgiving engines when it comes to running even when the rebuild is not done right.
DD

Doc,
Just for us that are new to this engine stuff, what is the rod bearing clearance? Is that the space between the rod bearing and the crank shaft, or is it the space between adjacent rod caps? I had a 225 worked over and the crank needed to be re-ground. I put it back together using the rod bearings supplied with the rebuild kit my machinist provided. They should be sized according to the amount ground off the crank, right??? If you are talking about the space between rod caps, how do you control that? There doesn't seem to be any way to make adjustments.

Jerry

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

The rod bearing clearance is that measured (by plastigauge or sensitive micrometer) between the rod bearing and the crank (rod pin) journal. This should be 0.0015" or so on a performance Slant. There is no way to adjust this except by machining or polishing the crank.

If you are in doubt, pull a rod cap off (or all), move the rod off the journal, then place a piece of plastigauge paralled to the crank axis and laying on the crank or rod cap. Retorque the rod bolts, remove them again, and check the plastigauge compressed width and compare to the chart on the plastigauge box. The machinist should have either done this, or been confident enough in his work that the clearances would spec out OK. The bearings you use should fit the crank dimensions as it has been machined - 0.010" undersize is very common.

There is no space between rod caps, and you should never shim them, unless you're selling the car soon...

I checked all rod and main clearances on my last motor, and they were all within 0.0002" of what I asked for.

Lou

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Home of Slant6-powered fun machines since 1988

Plasti-gauge is a great way to check bearing clearance, it's cheap and easy to use.

As Lou said, the clearance is set by the size of the crank journal but the clearance is also influenced by the size of the con. rod "big end" hole size.

This is why I asked if the rods were resized, this is a machining process where a small amount of metal is ground off the cap's mating faces, then the rod is re-assembled, torqued to spec then honed to a specified size. Doing this makes sure the rod end is round (they get stretched oval with use) and creates bearing "crush". It is the bearing crush that holds the bearing insert in place, not the little tabs you see.

If the con rod end is oval or does not provide the proper crush on the bearing insert, the bearing will fail, sometimes quickly other times after some use, even if the crank journal is perfectly sized. Recondition your connecting rods as part of a rebuild. If you can't afford this, at least measure the used rods to make sure the "big ends" are not way out of shape or oversize.
If you don't, things get ugly.
DD

looks like number three to me

That one is the number 6 rod out of that junkyard motor I sprayed to death a while back.
DD

I will definitely take a look at the rod bearings to see whats going on. So the clunking can be the crank banging against one of the rods, I assume.

I'm crossing my fingers I don't have to go through another rebuild.

Thanks guys,
You just confirmed what I thought I understood about all you discussed. I had read up on about everything I could get my hands on before doing a complete rebuild. I have a lot of confidence in the machinist who did all the machine work. We did have to regrind the crank which was too far out of tolerance. I do remember reading 0.010 on the new rod bearings.
Using plastigage was about the only thing I did not do while putting everything back together. The machinist had mic'd everything and felt good about by-passing that step. We'll see how good he is when we crank her up the first time. The engine is all back together and completely painted, waiting patiently on its stand for us to finish the engine bay.

Thanks,
Jerry

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

Man...
So the motor came out today. I had looked at the flex plate/converter bolts and gave them a visual look over before, and they seemed fine. So when it came time today to remove the motor and I was coming to pull the bolts out... 2 or 3 of the 4 were loose. What had happened was when the tranny was getting rebuilt, the guy put a reconditioned torque converter on there. So after we got the engine and tranny back in and came to put the bolts to the flex plate back on, the holes were stripped. So instead of dropping the tranny or pulling the engine to remove the torque converter, we just used a right angle drill and put in some helicoils. In the bolts that were loose, the helicoils were driven all the way back and touching the torque converter....
Moral of the story, don't use heli coils on torque converter bolts.
Well if the tranny shop won't give me another converter when I try to warranty it with them, where do you guys suggest I get one? Would a high stall unit be appropriate for a relatively stock engine? (stock cam, bored 30 over, clifford shorty headers & intake, GM 2 barrel efi system or holley 390 carb)

Looks like tranny shop is going to warranty it for me but I will have to wait untill next week to pick it up. Yay.

So, you feel the stripped TC bolts were causing all the noise, can you see where the heads were hitting the block?
A lot of work to fix but better then rebuilding an engine!
DD