Crank identification - 3.4 DOHC - Is it better?

[davida1_hiwaay_net]

Nope, my engine is nothing like what you are doing lol...

Mine is an inline 2.8, a Nissan L28E to be exact, running off the GM EFI.

That's cool. I see you wanted something tunable and used $59 for it.

I looked at King Engine Bearings for this engine, and they have the small groove in the lower main insert. I guess that's the lead-in groove. I like that and will probably order those, IF I can get them.

Thanks. By the way, looking at your sig, this engine is similar. I'm using a distributor with MSD but same Code$59 program.

By the way I did not get a 3x00 engine. The top end did not scare me, but the oil pan is totally different, bolts to the main caps and is not compatible with the old school front timing cover. So I got a 1991 model 3.1 engine. I tore it down to a short-block at the yard and they only charged me $90 for everything from block down. I'm tearing it down and it is *LIKE NEW* Very very happy.

Sincerely,
David

Nope, my engine is nothing like what you are doing lol...

Mine is an inline 2.8, a Nissan L28E to be exact, running off the GM EFI.

[davida1_hiwaay_net]

Back to the engine build - The machinist isn't done with the cam bearings yet. They are really busy! They are installing SBC cam bearings in the block.

I worked on the heads today, porting and cleaning them. I feel as if the iron head engines can benefit quite a lot from simple porting such as gasket-matching the intake ports and blending / smoothing the valve bowls. I didn't spend a long time on this, maybe 2 hours. Did a similar porting job years ago on a carb 2.8 and it made a very noticable difference.

Before:




After:


Also, as suggested I cleaned up and blended the oil drainback channel - removing casting flash and creating a smooth path for oil to return to the block from the valvetrain.





Valves all cleaned up. Will probably take them to the machinist to get them ground, IF they won't clean up by lapping. There is hardly any wear, just some light pitting on the exhaust valves. The intake valves looked unused after polishing.



I've got to order pistons for this. Thinking about these Sealed Power WH562CP hypereutectic coated skirt pistons. I really like the coating on the skirts. Every one of these engines has scuffed pistons and piston slap; and this looks like a way to avoid it.

They are standard for an iron head 3.1 so the compression ratio should be OK for this build. Feel free to comment as I am open to suggestion; but cost is a factor on this build.

EDIT: I have ended up with 2 threads on this same car, so I'm going to go back to the other original thread at http://60degreev6.com/forum/showthre...l-85-Celebrity for the remainder of the build.

[geoffinbc]

I used the same bearings in my current 3.2L. I did not add the second oil hole. But it is easy to do if you want. The Chevy Power manual has some details on modifying the 660. Although it does stop at the Gen II engines since it is an older publication. But when they mention the SBC cam bearing installation they never talk about drilling a second hole so I never did it.

[Superdave]

I used the Durabond coated ones in my 3500, the only thing the shop did extra was add a 2nd oil hole in the front bearing like the stock one had.

[davida1_hiwaay_net]

Are you going to use the wider SBC cam bearings or stock replacements?

Good work so far on the block prep!

Thanks, I appreciate the comment there.

Didn't know SBC bearings could be used. Is there any modification needed for this to work? I'm going to search it now and see what I can find here about using these.

Sincerely,
David

[Superdave]

Are you going to use the wider SBC cam bearings or stock replacements?

Good work so far on the block prep!

[davida1_hiwaay_net]

Ok, here are some picts of the block cleanup and grinding job.

Washed and oiled up a little. Don't like the flash rust getting in it!


Before any grinding. There definately is some flash.


The new bearings are better. They have larger oil holes as well as oil groove on the lower insert. There is quite a bit of metal blocking some of the larger oil hole.


Oil groove design. I like this.


The new and the old.


Hole size comparison.


I drilled the old bearing to the same side as new ones. It will be a pattern for modifying the block, without risking a slip of the grinder and damagin the new ones.


Pattern in the block.


Modification done. Radius and blend the oil passage into the oil groove. Widen the bottom of groove from a V shape to a U shape, and add a "toilet bowl" area to match the larger bearing oil hole.


New bearing matched up prettywell!


This one was the rear main. It was the worst. This is after modifying.


All bearings line up well now.


That gets the oil TO the bearings. NOw to get it back to the sump. The casting flash gone.




I enlarged the 3 return holes which were not too close to the cylinder bores. This should help the oil to get back to the sump instead of getting trapped in the camshaft compartment.


So tomorrow I plan to drill and thread the turbo oil return hole and get the block ready for new cam bearings. I want to have the machine shop REMOVE the old cam bearings so I can inspect and possibly port or blend the main bearing oil feed at that location.

I will have company the next few days so may not be able to do much on it. Will post back here once it's going together again.

Sincerely,
David

[davida1_hiwaay_net]

A few oiling tips. Get yourself a small die grinder burr and blend the oil supply galley which is offset into the groove in the saddle. The saddle groove should match up well with each bearing insert. Remove the oil pump and the main and round over the large supply hole in the cap. In the oil filter mounting pad chamfer the outlet hole, remove any casting flash. Take a look in the return hole and see of any cleanup is needed. But be careful of the threads. Grind all the the oil return grooves in the cylinder heads and remove the casting ridge left behind. This will speed oil drain back.

Use a 3.1L/3.4L pump with the 3/4" pickup tube. It is a higher volume pump than the 2.8L pumps. Melling sells a high pressure version as far as I remember.

Thanks for the tips! I'm actually preparing for those mods now. The 3.1 block is notably better quality than the 2.8 was, but it still has room for improvement. The problem now is the block is too dirty to work and my pressure wash hose is still froze. We've had some really abnormal cold weather for this area.

I see the hole between the lifter gallery and the cam bearing bore oil groove is kind of small. For the two center cam bearings, it's feeding a cam bearing, main and rods through that small port. Wonder if increasing the size of that would be beneficial?

I'll bost pictures of the block cleanup as I get the chance.

[geoffinbc]

A few oiling tips. Get yourself a small die grinder burr and blend the oil supply galley which is offset into the groove in the saddle. The saddle groove should match up well with each bearing insert. Remove the oil pump and the main and round over the large supply hole in the cap. In the oil filter mounting pad chamfer the outlet hole, remove any casting flash. Take a look in the return hole and see of any cleanup is needed. But be careful of the threads. Grind all the the oil return grooves in the cylinder heads and remove the casting ridge left behind. This will speed oil drain back.

Use a 3.1L/3.4L pump with the 3/4" pickup tube. It is a higher volume pump than the 2.8L pumps. Melling sells a high pressure version as far as I remember.

[davida1_hiwaay_net]

For future reference, a Fiero 87-88 timing cover would bolt up to a 3x00 and retain the CW water pump. The water pump on a Fiero looks the same.

That's good to know, I appreciate it.

[caffeine]

For future reference, a Fiero 87-88 timing cover would bolt up to a 3x00 and retain the CW water pump. The water pump on a Fiero looks the same.

[davida1_hiwaay_net]

Here's the oilpan / timing cover setup:

[davida1_hiwaay_net]

Is the timing cover similar to a RWD timing cover? Or Fiero style (CW water pump)?

It has a clockwise rotation waterpump and vee-belts. Look at my other thread I think there is a picture of the engine on a stand with all accessories on it.

I found ONE lonely, abused 3.1 engine, with the upper intake manifold missing and the intake runners full of rainwater. It was my only chance, so I tore it down and found it was not rusted yet. Must have been from the rain yesterday. The car was a 91 Cavalier Z24, hit hard in the right rear quarter. Looked well taken care of otherwise, so the engine had a good chance of being usable - other than the water.

I got the engine (less the heads) for the cost of a block only, due to the water issue. Quite a deal considering the condition it ended up being in. The bottom end is near perfect. Two pistons have light scuffing but the crank is perfect, cam and lifters perfect, and there are no obvious defects.

Yes, I cut the seatbelts out of some hapless car and made lifting straps.. That was at the sugestion of the junkyard guy, by the way...


Front cover off. Looks a little varnished but the chain is no where near as stretched as the original one from the 2.8.


Camshaft out. No spalled lobes or scored journals. This is good!


Oil pickup screen is clean.


Comparison of the 3.1 piston (left) with an original 2.8 piston (right). The 3.1 piston is lighter weight. It will not put as much stress on the connecting rods at high RPM's because of less reciprocating mass. The top of the piston has a dish in it to lower the compression ratio. I will have to research it and see what kind of CR this will give. It may require new pistons with different CR.


Crankshaft rod bearing journal. Not a single scratch.


All the parts laid out, sprayed with corrosion inhibiter.

[caffeine]

Is the timing cover similar to a RWD timing cover? Or Fiero style (CW water pump)?