Engine rebuild questions?

[gstacky]

I have to rebuild my engine already(it's a long story), and I'm new to SyTy's, so I am in need of some opinions here.
First off, gasket sets. Is there a set that is for the SyTy engine? What is everyone's preference? I'm leaning towards Fel-pro, but I know that GM shows a different head gasket for a SyTy then any other 4.3, anyone know why?
Second question is spark plugs. My truck had ACDelco CR43TS in it. Is this right? What is a good replacement for a stock engine.
Third is about pistons. The engine has KB(Keith Black) pistons in it. Anyone have any opinions on these or know much about them?

Any help is appreciated, I just want to drive this thing.

 

[dgoodhue]

Re: Engine rebuild questions?

CR42TS is the stock plug, CR43TS is hotter plug which will promote detontion. SOme parts books incorrectly recommend the 43 plug.

The head gasket is different because of boost. I wouldn't use the Felpro gaskets, get the OEM Victor Reinz gaskets.

 

[gstacky]

Re: Engine rebuild questions?

Good to know on the plugs, thanks.
Is there a thinkness difference in our head gaskets due to the boost?

I have also read on here about oil pumps and to not use a high pressure oil pump, why is this?

 

[JSM]

Re: Engine rebuild questions?

Keith black doesn't make forged pistons do they?

So why do you need a new motor?

High pressure/high volume really are not needed if you have it built right IMO.

 

[Foot Performance]

Re: Engine rebuild questions?

Keith black doesn't make forged pistons do they?

So why do you need a new motor?

High pressure/high volume really are not needed if you have it built right IMO.

The only keith black piston I have seen were the cheap ones jegs sells and they are junk.

As far as oil pump I run HV pumps on my small block build (havent done a 4.3 yet) but the main diffrence I have seen is usuall 40-60 psi and the stock pumps usually run 20-40 (atleast the ones I have messed with :2cents: )

 

[blk00z28]

Re: Engine rebuild questions?

High pressure/high volume really are not needed if you have it built right IMO.

Is that just for a basic rebuild, or would this still be for a built motor?

I ask because my rebuild I'm planning on making some power and considered using the/a stock oil pump. Maybe slightly ported, but stock none the less..

 

[gstacky]

Re: Engine rebuild questions?

I am just building stock, it's a low mileage truck and I just want it stock. Whoever had it before me changed the piston's to KB's, and I'm having some extras given to me, so I think I will just stick with them. Yes they are forged pistons, and should be the right ones for the lower compression these engines need.
Does anyone know the cc of stock Sy cylinder heads, I haven't found it yet.

 

[gstacky]

Re: Engine rebuild questions?

The second time I had the truck out since buying it, I was driving down the road and poof, white smoke. Thought it was a head gasket, pulled it out to find out that it was just rebuilt and whoever installed the KB pistons didn't gap the upper rings properly. KB's need a lot more gap due to placing the upper right a lot higher on the piston. Anyways, ring stuck in cylinder, broke top of piston off and put a hole in the cylinder wall. I am getting the block fixed right now and hope to get it back together soon.

 

[dgoodhue]

Re: Engine rebuild questions?

Anyways, ring stuck in cylinder, broke top of piston off and put a hole in the cylinder wall. I am getting the block fixed right now and hope to get it back together soon.

Are you sure the piston rings were stuck? What you describe is often happens from detonation.

 

[dgoodhue]

Re: Engine rebuild questions?

Does anyone know the cc of stock Sy cylinder heads, I haven't found it yet.

It's around 62-64cc's

 

[blk00z28]

Re: Engine rebuild questions?

The second time I had the truck out since buying it, I was driving down the road and poof, white smoke. Thought it was a head gasket, pulled it out to find out that it was just rebuilt and whoever installed the KB pistons didn't gap the upper rings properly. KB's need a lot more gap due to placing the upper right a lot higher on the piston. Anyways, ring stuck in cylinder, broke top of piston off and put a hole in the cylinder wall. I am getting the block fixed right now and hope to get it back together soon.

So your sleeving the block, or what?

 

[gstacky]

Re: Engine rebuild questions?

Yep sleeving that one cylinder. These pistons are known for doing this, and I measured the gap on the others and they all were the same. It broke the piston on the outer edge where the piston ring sits, detonation is usually a hole in the center isn't it? KB shows a piston with the same problem on their site, and it's from not enough gap on the upper ring.

Anyone have a picture of a stock piston so I can compare to the ones I have?

 

[dgoodhue]

Re: Engine rebuild questions?

It broke the piston on the outer edge where the piston ring sits, detonation is usually a hole in the center isn't it?

A majority of the broken stock piston failure that are from the broken ring lands, which I think is what your describing. Detonation is usually causing the problem with the stock pistons.

 

[JSM]

Re: Engine rebuild questions?

SBC motors and I will say the 4.3 v6 since it is very similar are known in racing circles for pumping all the oil up into the cylinder heads. HV/HP will make this problem worse.

I blew up 2 motors from what I suspect is this problem, I think I have it fixed now with a stock volume/pressure pump and 3 extra quarts of oil from an accusump. I also paid special attention to the drainback holes in the heads and block hoping oil drains back faster.

They do make/sell restrictors for block to help with this also.

Just my idea/theory here.

 

[turbodig]

Re: Engine rebuild questions?

There's nothing wrong with the Silvolite/KB Hyperutectics, as long as they're the right CR and that the clearances are set up properly (ie, a bit looser than you would on a non-turbo motor). They won't withstand the abuse that forged slugs will, but they'll hold up fine if it doesn't ping.

All else being equal, that motor either detonated or preignited (the latter being more likely) itself to death via a fuel, boost, or timing problem. Rebuilding a motor without finding the cause will result in another dead motor.

First order of business after getting the motor back in will be to get a laptop with some scan tool software hooked up to see how much deto you're seeing.

 

[gstacky]

Re: Engine rebuild questions?

Well, unfortunately I don't know enough about this truck yet to tell what exactly it was doing, only drove it twice before this happened.
What I have found out is that these pistons seem to be the wrong ones. With calculations they will be giving me a compression ratio of over 9:1, which is too much, should be in the 8.5:1 range right?
I now know that the wrong plugs were in it, and who knows what they were burning for fuel, probably good old 87, so there could be a lot of things that happened to this thing. But I know for sure that the upper rings were too tight, also contributing.

Anyone have any stock pistons laying around, hahaha.

 

[blk00z28]

Re: Engine rebuild questions?

SBC motors and I will say the 4.3 v6 since it is very similar are known in racing circles for pumping all the oil up into the cylinder heads. HV/HP will make this problem worse.

I blew up 2 motors from what I suspect is this problem, I think I have it fixed now with a stock volume/pressure pump and 3 extra quarts of oil from an accusump. I also paid special attention to the drainback holes in the heads and block hoping oil drains back faster.

They do make/sell restrictors for block to help with this also.

Just my idea/theory here.

Good to know Jeff

 

[turbodig]

Re: Engine rebuild questions?

Well, unfortunately I don't know enough about this truck yet to tell what exactly it was doing, only drove it twice before this happened.
What I have found out is that these pistons seem to be the wrong ones. With calculations they will be giving me a compression ratio of over 9:1, which is too much, should be in the 8.5:1 range right?
I now know that the wrong plugs were in it, and who knows what they were burning for fuel, probably good old 87, so there could be a lot of things that happened to this thing. But I know for sure that the upper rings were too tight, also contributing.

Anyone have any stock pistons laying around, hahaha.

The combination of too high of a CR (on stock programming), poor gas, and too high of a heat range plug is pretty much a recipe for destruction.

Talk to Hood (hoodtunedperformance.com). He can hook you up with the proper replacement stock pistons.

 

[JSM]

Re: Engine rebuild questions?

Good to know Jeff

Let me also add relative to racing motors our RPM's are very low. For example Jeremy's race car stall is about where our redline is.

We just don't turn the motors over very fast relative to a NA motor.

 

[gstacky]

Re: Engine rebuild questions?

There's nothing wrong with the Silvolite/KB Hyperutectics, as long as they're the right CR and that the clearances are set up properly (ie, a bit looser than you would on a non-turbo motor). They won't withstand the abuse that forged slugs will, but they'll hold up fine if it doesn't ping.

All else being equal, that motor either detonated or preignited (the latter being more likely) itself to death via a fuel, boost, or timing problem. Rebuilding a motor without finding the cause will result in another dead motor.

First order of business after getting the motor back in will be to get a laptop with some scan tool software hooked up to see how much deto you're seeing.

Ok so if this is the case, what do I need to start rounding up as far as software goes to check this out, remember I'm new to this stuff, haha