It's time to deliver - there comes the images for the 4.3 V6 mild build.

Starting with the teardown of the engine itself. Had the engine sit on a palette nice to move around using a fork lift. Lifted up onto a table and taken apart.

TBI off, then the accessories from the intake manifold, the manifold itself, sensors and stuff from the heads and finally the heads.

This engine has 105'000 miles on it and looks pristine. Despite the car being fully rusted it shows that the truck had been serviced as per manufacturer instructions. The valvetrain and all internals are witness of this. Little, to nearly no wear. Even the hone on the cylinders is still there. Something to be expected from a low power low rpm installation which has been serviced well.

 

Had it put upright on the back side (flexplate side) for an easy access to the front cover and assemblies.
At that time I had no access to an engine stand. But for a tear-down it is not required in my opinion.

Heads are off, all stuff around is off and the oil pan is gone. Next step will be rotating assembly and pistons.

 

Taken the rotating assembly apart and finally removed all the mains to pull the crankshaft.
All was looking o.k. could have been used again without hesitation. The crankshaft shows abrasion from particles. Under the microscope we found out that they were mainly from casting sand.

The bearings show wear on the thrust side something that is witness to poor lubrication at times. The truck had very long periods where it had not been run. (1 - 2 years at times).
At the same time many particle traces on the crank could be traced to particles now embedded in the bearing shells. (This is what the soft surface is supposed to do.)

Barely acceptable for an OEM and it could have been put back together to run an additional 100'000 miles using the same bearings in the exact same location. Not something to do when doing a build. The crank needs re-surfacing (grinding) one size under and new bearings. But I got a better crank which fits and is nicer.

The pics show:
- Rod bearing and crank thrust with scratch.
- My rod and piston packing
- A rod bearing showing surface abrasion and contact patches
- timing chain assembly
- a main bearing with a deep scratch through a part of the bearing. At the end of the scratch was found the particle that caused it.
- the crank with all the scratches
- a piston with the carbon buildup. Nice ring wear and just minor scuffing on the skirt.

 

Taking all the stuff from the heads apart. Again all looking like what you would expect from this engine. Will decide on the valve size later on in the build once I've got my pistons and can measure clearances to the pockets.

At the same time on the outside of the heads I ground all casting ridges and flesh away. Chamfered all sharp edges, more on the outside just a little on passages or where gaskets will be employed. I hate cutting my fingers on that stuff and these heads will be handled a lot before they go back onto the engine.

Pictures show:
- valves of one head - the liquid is from the parts cleaner.
- Combustion chamber, again the liquid is not oil but from the parts cleaner
- Head with ground casting ribs and sharp edges chamfered.
- various exhaust valves in different states of cleaning. Brushed them but no polishing as I will get new ones most probably.
- the camshaft and part of the valvetrain including one of the valve covers after a bath in the parts cleaner.
- the lifters (could be reused without hesitating)

 

The project is in no hurry which has suited me well. In the meantime I found a couple friends with the capabilities and interest to share their knowledge on fuel injection systems, ECU tuning and such to bring the build forward. The camshaft from COMP Cams is according to their advertising compatible with stock computer but I can even accept a tune now. Something that I will do anyways now that I can. A proper tune on the ECU will help with efficiency and fuel economy.

After 3 months the JE custom pistons finally arrived. Beautiful stuff! Measured and done a mix and match to adjust masses with the pins. Now I have to adjust a maximum of 1.5 grams on one piston while the others will be in the 0.8 gram range. I was wondering that the pistons had up to 3 grams of difference between them and the pins 1 gram of range. For once it has suited me well, so I have been able to reduce the difference to less than 2 grams without machining.

Taking the OEM pistons apart needed a press. CC'ing the heads had me wonder because the final compression this engine had was around 8.9:1, far from the advertised 9,3:1. It has no squish area that can be called such because of the pistons resting more than 0.050 below deck. With the gasket it ended up being 0.100 inches. No squish whatsoever. The dish and 4 pockets added even more volume (22 cc's BTW) to lower compression. No wonder the OEM 4.3l V6 is a pathetic engine.

Would be nice one day to just put a set of zero deck flat top pistons into an OEM engine without any other changes and see what the outcome is. (3 - 5 % more hp/torque?).

Some random pics of the front cover with paint removed, valves polished to be used for the cc'ing a rod on the scale and preparing the JE stuff. The last step as two days ago is that I have the pistons matched to their respective pins. Pins marked (electric arc tool) Pistons marked for their respective cylinders getting ready to be machined for weight.

Pictures show:
- pressing the OEM piston bolts
- cc'ing the combustion chambers
- the timing gear cover after paint and rust removal - waiting for powder coating
- a set of valves polished - will be using these for the cc'ing and valvetrain geometry.
- weighing the OEM rods - just out of curiosity. They came out very close to each other within 1.7 grams.
- unpacking the JE pistons forged pistons
- the respective ring set - all ordered for file fit - this way we can play with the hone to adjust for correct clearance and file fit the rings to match
- weighing the new pistons and compiling the master weight (mass) chart.
- pistons mixed and matched. Because of the 6 cylinder you need a set of 4 lefts and 2 rights. Just marked with paint, before marking them definitively

 

Loving the attention to detail; glad you have access to a machine shop! Do you think 10:1 CR will be achievable, even with all that clearance still?

 

Thanks - I try to be a good engine builder

Attention when building engines is the difference in taking apart an engine and wondering if the mains and rod bearings have ever been used or finding them full of debris and scratches.

Clean workspace - e.g. new pistons will never be placed barely on the table where they pick up filings and other debris. After machining cleaner, brushes and hot tank them every time.

The pistons are 146 grams lighter than stock which may enable us to change the crankshaft to an internally balanced one.

Building with custom JE Pistons. They are sitting 0.011 inches below deck now. After straighting the decks and minimal machining the pistons will sit 0.008 inches below deck and I'll use a COMETIC 0.027 or 0.030 MLS gasket. This would end in a 11.1:1 compression as the JE pistons have only 4 cc reliefs.

Machining the combustion chambers to same sizes on all pistons and rounding out the bosses will put compression to a range of 10.4:1 to 10.8:1.

More pics coming. I'll also supply the specs once I have all measured.

Next headache is where to machine the beautiful JE Pistons for these 1.5 grams

Found out that I don't need to work on the pistons. Could mix and match them with the differences in pin and small end weight of the rods. I'm below 1 gram now on the rotating assembly. Next will be the heads valvetrain and the crank.

 

Nice work man!

 

After having disassembled both heads I just had them deburred and chamfered on the outsides. I hate cutting my hands on sharp stuff, especially with a build where I will have to handle the heads dozen's of times.

Some pics, from what they looked when coming off the engine, after hot tanking and deburring. CC'ing the chambers had the surprise that they were within 0.3 cc's of each other. The highest number was 65.2 cc's which will most probably go up to 66 cc's because of the work on smoothing out the chambers. Cutting the heads will most probably remove 1 cc so my calculations are based on a 66 cc chamber. Even with a pessimistic assumption it will put compression to 10,8:1 as the lowest value.

The OEM style rocker studs were pressed in ones. Pulled them with a sliding hammer, then machined the bosses for equal height, chamfered and cut 3/8" threads through. For the next step once the clearance of the valves to pistons is defined with the new camshaft we will have to cut the bosses further down by about 1/8" for proper geometry with the rocker arms. There is plenty of thread with these bosses (about 1"). Within the inlet channels I will just round the edges but not go the hassle to epoxy the holes. It's a street engine not a race engine.

The valvetrain with the COMP Magnum roller rockers will no longer clear the plastic valve covers. I cannot get proper covers for this engine which would clear the air filter element. The plastic covers have a nice geometry and I will most probably just make an aluminium spacer about 7/8" thick with an o-ring groove on the lower side to rest on the heads rim as the OEM valve cover did and the top flat as for the OEM style gasket to have a seat. Will need some longer bolts but will most probably do them myself with a T on the top end for appearance and easy removal.

The pics show:
- cc'ing the combustion chamber a second time
- pulling the OEM pressed in studs
- the 4.3 V6 in good company. A 350 1970's corvette engine that had been f****ed up by the engine builder because they sanded the intake manifold. 2 quarts of oil on 120 miles.
- milling the stud bossed
- cutting threads into the bosses
- test assembly of the valves and rocker arm (just bought one 1.6:1 rocker arm for testing)
- side view of the rocker arm
- witness mark for valvetrain geometry. (This is still no good as this is the mark left on the extreme position. Rocker arm needs to go lower.)
- clearance issue with the valve cover. There is about 7/8" now but with lowering the rocker arm for correct geometry will add the clearance needed with a 7/8" spacer.

 

I have access to a company who does dry ice blasting and I can use the left over pellets sometimes to clean my stuff. I do their website and PR stuff. We had used my parts for demonstration purposes and to take pics.

Some pics from the cleaning of the valve covers. The covers had been in the parts cleaner and brushed two times to no avail. The brown gunk sticking to them in every crevice. 5 minutes with the dry ice and they looked pristine. Plastic surface had not even a scratch.

Same for the pistons. Especially the ring grooves came out mint! Whenever doing a rebuild and reusing pistons I will definitively go for this method. Has removed all the soot and more important the residues from the grooves without scratching. Passed a Kleenex through them and came out white.

Left piston is as it came out of the engine and just cleaned with a rag. Middle piston is after a thorough wash in the parts cleaner and wiping clean with a rag. Right is piston like the left one after 3 - 4 minutes.