First for those who are not aware of it GM has an HO version of this engine rated at 270 hp and 258 lb/ft, not sure when or if it's being released.

I came across this engine very, very cheap and discovered some information I had not read about it in any GM literature, for example, it has full floating Mahl pistons which is interesting because the 3.6 DOHC does also and its pistons are forged aluminum which makes me wonder if these are also, it also has a steel crank which is a bit more refined than the steel crank in my 3500 which has more unmachined rounded weights. Here is the paragraph from GM's site about the 3.6L pistons:

Aluminum-intensive construction extends to the pistons, which are manufactured of forged aluminum and considerably lighter than conventional steel pistons. Less weight means less reciprocating mass in the engine, which in turn means less inertia and greater operating efficiency. Moreover, the V6 VVT pistons are crafted with a number of features that enhance durability and reduce noise and harshness, including a high-tech polymer coating and floating wrist pins. The V6 VVT engine family was developed with pressure-actuated oil squirters in all applications. Three jet assemblies in the block hold a pair of oil-squirting nozzles that drench the underside of each piston and the surrounding cylinder wall with an extra layer of cooling, friction-reducing oil. The jets reduce piston temperature, which in turn allows the engine to produce more power without reducing long-term durability. The extra layer of oil on the cylinder walls and wristpin further dampens noise emanating from the pistons



Oil squirter


Large upper plenum ports


Large intake runners like the Lsx engines, the rocker base was shortened compared to the earlier design to accomodated the mod


The valves are huge 1.87 int 1.52ex


There appears to be room for an further exh valve increase

[This message has been edited by Joseph Upson (edited 07-28-2007).]

The rockers are a lot sturdier than the previous design stamped rocker






The head gasket is a unique 3 layer design

Does this have oilers on all 6 pistons or just the rears?
also look here
https://www.fiero.nl/forum/Forum2/HTML/079360.html
I can get all the info you want on this engine. Let me know. The 2.8L, 3.1L, 3.4L, 3.5L and 3.9L all have used Mahle pistons OEM.

All of the 3900s have oil squirters on all 6 pistons and only the Impala and I believe the Monte Carlo get active fuel management (3 cyl capability) for 07. All of the 3500s in 07 run the 3900 bore with the shorter stroke. As for the pistons It wasn't so much the manufacturer as it is the design in which the previous V6s did not have floating pins and if I remember correctly they also have a metal plate incorporated on both sides of the piston for reinforcement which unless they are incorporated inside these do not appear to have which raises the question about the possibility they are forged like those in the 3.6L which also have floating pins. It has already been proven that despite GMs documentation stating certain SUVs received the steel crank that several passenger vehicles received it also.

I'm aware of the 3900 info on the 60 degree forum but to my knowledge none is posted here and CNCguy is busy doing real work so the info stream on his 3900 and VVT cam delete has stopped.

Why would you go away from VVT?
I will add to the other thread the info I have.

quote Originally posted by AJxtcman: Why would you go away from VVT? I will add to the other thread the info I have.

VVT requires a lot of information to function properly, which probably requires a considerable investment to control in the manner it was intended in a vehicle that did not come with the option therefore requiring additional computers and likely decreased dependability. It's a 3.9L with outstanding performance characteristics and even without VVT would perform quite well with the cam fixed in the traditional non VVT degree angle until a controller comes available.

I don't believe in engines without turbochargers and since the 3900 has heads that flow even better than those found on the first design 3500 which has heads that flow better than all of the previous 60 degree V6 aluminum heads, once boost is applied I believe the output at low boost will be phenominal with or without VVT. I have an idea for a controller but need information on the function characteristics to even consider how to approach it. It's obvious there is a series of pulses that are probably determined by CPS, Cam sensor, rpm, MAP, and TPS and maybe even MAT. Won't know until I can get GM documents on it via the ~$120 shop manual.

[This message has been edited by Joseph Upson (edited 02-19-2007).]

Every time I see the intake top of that engine, I think of the Buick GN. Other than that, it looks like that would be a good engine to mod with those oil squirters. Isn't that what the Type-R Honduh engines use for cooling as well? How well do you think this engine would take to S/Cing or a high boost turbo? Hi boost being about 12-15 PSI, which I think is high enough for a street engine.

quote Originally posted by AquaHusky: Every time I see the intake top of that engine, I think of the Buick GN. Other than that, it looks like that would be a good engine to mod with those oil squirters. Isn't that what the Type-R Honduh engines use for cooling as well? How well do you think this engine would take to S/Cing or a high boost turbo? Hi boost being about 12-15 PSI, which I think is high enough for a street engine.

Still waiting on MAHLE for info on the stock pistons they make for it to see if they are forged like the floating pistons in the 3.6L. The head ports are designed similar to the LSx engines with a high port ceiling and the valves are much larger than previous engines. There are documented stock 3400 engines with over 320hp and lb/ft on 9-10 psi nearly 100 hp per litre. If the VVT can be harnessed so that it can be taken advantage of given the considerable efficiency the 3900 has above the 3400 I would expect 400 hp or more with cam phasing kicking in especially with a modified cam. I mentioned earlier that GM has a 270 hp HO version of it.

[This message has been edited by Joseph Upson (edited 02-19-2007).]

i havent heard of any engines using steel pistons for a long time , if ever .cast aluminum is the most common stock production piston .forged aluminum in all its varients is usually the upgrade.

This is for 2006 Chevrolet "Z body" Malibu 3.9L
It looks the same for 3.5L and 3.9L Monte Carlos and all W bodies
Engine Component Description
The cylinder block is made of cast alloy iron. The cylinder block has 6 cylinders that are arranged in a V shape. There are 3 cylinders in each bank. The cylinder banks are set at a 60 degree angle from each other.

The left - front bank cylinders are 2, 4, 6. The right - rear bank cylinders are 1, 3, 5. Firing order is 1-2-3-4-5-6.

Four main bearings support the crankshaft. The crankshaft is retained by the bearing caps. The bearing caps are machined with the block for proper alignment and clearances. The main bearing caps are drilled and tapped for the structural oil pan side bolts.

The aluminum cylinder heads have individual intake and exhaust ports for each cylinder. The valve guides are pressed in. The roller rocker arms are located on a pedestal in a slot in the cylinder head. The roller rocker arms are retained on individual threaded bolts.

The crankshaft is forged steel with deep rolled fillets on all 6 crankpins and all 4 main journals. Four steel-backed aluminum bearings are used. The #3 bearing is the end-thrust bearing.

The camshaft is made from a new metal composite design. The camshaft profile is a hydraulic roller design. The camshaft is supported by 4 journals. The camshaft includes an oil pump drive gear.

The pistons are cast aluminum using 2 compression rings and 1 oil control ring. The pistons also have 2 polymer coated patches on the skirt for noise reduction. The piston pin is offset 0.8 mm (0.031 in) towards the major thrust side. This placement allows for a gradual change in thrust pressure against the cylinder wall as the piston travels its path. The pins are made of chromium steel and have a floating fit in the pistons. The pins are retained in the connecting rods by piston pin retainer clips.

The connecting rods are made of forged steel. Full pressure lubrication is directed to the connecting rods by drilled oil passages from the adjacent main bearing journal.

A roller rocker type valve train is used. Motion is transmitted from the camshaft through the hydraulic roller lifter and from the pushrod to the roller rocker arm. The rocker arm pivots on the needle roller bearings. The rocker arm transmits the camshaft motion to the valve. The rocker arm pedestal is located in a slot in the cylinder head. The rocker arm is retained in the cylinder head by a bolt. The pushrod is located by the rocker arm.

The intake manifold is a 2-piece cast aluminum unit. The intake manifold centrally supports a fuel rail with 6 fuel injectors.

The exhaust manifolds are cast nodular iron.

Those rocker arms look alot like one off an LSx series engine which resemble 3800sc rockers also. As for the oil squirters I read somewhere that the 4.4sc uses these and allowed them to run more timing of which they ended up getting about an extra +/- 20 hp.

quote Originally posted by bluhevn86: Those rocker arms look alot like one off an LSx series engine which resemble 3800sc rockers also. As for the oil squirters I read somewhere that the 4.4sc uses these and allowed them to run more timing of which they ended up getting about an extra +/- 20 hp.

The heads were designed with the LSx in mind according other GM literature and should flow even better than the 3500 heads which have already been proven to outflow the 3400 heads.

The 2.8 heads fit the 3900 block, the bolt holes line up but the head gaskets would require some reworking regarding the water passages. There is extra deck area on both sides of the head due to the increased cylinder bore but the heads appear to be in the correct location to properly seal against the intake manifold.









The combustion chamber is off center by about 1.5 mm I believe I didn't measure but apparently that's how far GM moved the cylinder bore.






An amazingly sharp eye will note the two valves on the left are different and that they are V8 valves, 1.94int 1.50exh

[This message has been edited by Joseph Upson (edited 03-15-2007).]

I let this thread fall by the way side but since it hasn't been closed I'll add some new info to it.

I'm currently discussing with a machine shop the possibility of boring this engine block to four inches for the possibility of cheaper and more readily available forged small block chevy pistons. The stock bore is 3.9". Since there are several different rod length combinations sbc pistons are made for it shouldn't be difficult at all to find a production model with the proper piston pin height to address the deck height difference between the 5.7L and the 3.9L. The 5.9" rods and 2.25" crank pin leaves plenty of room for making the upgrade easier, although it would be better to maintain the added integrity of the steel crank and larger crank pins by using the stock rods as opposed to machining the crank to accept the smaller big end forged sbc rod since according to the shop tech the newer powder forged rods are stronger than the earlier forged steel rods but like hypereutectic pistons are brittle lacking the ability to take a heavy side blow, not sure how that relates to engine related stresses.

As for the heads, since they are designed after the LS1 heads there is a good possibility that the stock 1.87 int. and 1.52 exh valves can be replaced with either of or both of the LS1 valves, 2.00 int and 1.55 exh valve. Since the aluminum head valves are splayed I believe the possibility of shrouding will be less of an issue.

Picture is compliments of CNCGuy from the 60 degree site.




The VVT issue is really a non issue considering you are limited in how much benefit you can get from a non independent intake and exhaust valve variation as opposed to independent as found in the 3.6L DOHC engine which in a sense can display practically every cam lobe degree association that can be programmed into the ecm lacking only the ability to change lobe ramp profile; aggressive vs. mild. I basically blocked the cam phaser at full retard which for my camshaft regrind was only slightly retarded from being straight up which should favor more top end power on an engine with a stock peak output at 6000 rpm and 6400 rpm redline. I used hollow aluminum tubing to block the phaser vains, I accidently deleted the pictures.

I'll post the results of what I find on the mod possibilities.

Pics from CNCGuy

[This message has been edited by Joseph Upson (edited 01-15-2008).]

I've decided to build a forged rotating assembly later this year which only requires a piston change in the 3900, so I'll keep this thread going since the engine in this thread is sitting quietly in storage. What I know so far;

The forged powder metal rods from what I've read are apparently stronger than the previous forged steel rods.

http://www.metal-powder.net/business/jun2005.asp
http://metaldyne.com/metald...a/ConnectingRods.pdf

GM states the rods are 5.9" but I along with someone else measured 5.827". It is bushed for floating pistons. Current engine fuel cut is 6400 rpm.

The stock piston compression height (C/H) is 1.305" with an ~18 cc dish and 3.898" diameter the same as the early LS1, they also have offset pins as found in the LS1 pistons.

There are several forged LS1 piston options available off the shelf that will work in the 3900 with the stock rod, and LS1/SBC 6", 6.098" etc forged aftermarket rods and offset stroke increase if you want:

Stock center rod big end to the top of piston = 7.13". below are some off the shelf forged LS1 piston and rod combos that I have calculated:

LS1 piston 1.155 C/H + 6" rod = 7.155"

1.295 C/H + stock rod = 7.122"

1.050 C/H + 6" rod + .075" offset grind = 7.125"

1.050 C/H + 6.098" rod = 7.148"

Best quote to date is $321 for 6 forged LS1 pistons, 1.315 C/H, 13.2 cc dish to work with stock rods, addition of valve reliefs should end up pretty close to 18 cc or more.

If I choose to have the crank offset for 6" LS1 rods ~$350. The 3900 block is already relieved for stroke increase.

Some minor mods may have to be made depending on combination choice, .927 pin vs stock .942 may require bushing change or piston pin hole resize for stock rods.

Valve reliefs will need to be cut.

Since I intend to keep the turbos I will aim for a compression ratio of around 9.2:1, and will have my other stock cam reground with a little more duration and more lift instead of the high rpm grind I have now, I will also restore VVT function in an on off capacity based on rpm unless completion of tuning with the current cam suggests I leave it as is.

I really believe focusing on the cylinder heads and leaving the cam alone altogether would probably be just as effective as a cam upgrade.

I would really like to check into the possibility of over boring the 3900 block from 3.9 to 4" for a possible 60 degree 4.3L.


The crank pins are 2.25" vs the V8 crank 2.1" that's what makes an offset grind more practical

[This message has been edited by Joseph Upson (edited 08-13-2008).]

I found a price on a set of brand new forged MAHLE pistons complete with pins and rings that I just couldn't refuse, $381 shipped. That's a drop in the bucket compared to a custom forged set especially when a cost per piston avg is calculated, in addition to these there are several other options.

SPECS:
.
Bore 3.898" same as stock.
Compression Height, 1.314", stock 1.305
Dish, 9 cc, stock 18 cc.
Pin, .927, stock .942. I don't recall the weight exactly but it's lighter as well, 119 g vs 155.9g.
Weigth 402 g, stock 420 g.

It will cost about $100 to have valve reliefs cut, or I can buy the tool for about the same price and do it myself. The dual reliefs should bring final volume to about 18cc.
First quote for swapping out the stock rod bushing for a .927 bushing is $17ea, I'm sure I can have it done cheaper, or I can have the crankshaft offset ground to increase stroke by .075" and use forged 5.7" chevy rods and come up with a compression ratio of a calculated ~9.11:1 compression allowing for more boost in addition to a greater displacement.

If I use the old stock 5.7" rod from the earlier V6 motors I can increase the stroke by .100" since the pin diameter would be decreased further, down from 2.1" for the chevy rod to the old stock 2.00". The crank is forged steel and should still be fairly strong. VVT is really not a problem regarding using this engine, further more for those with a stock 3.9 engine in its stock car these modifications would make for a high performing naturally aspirated upgrade.

Stock is on the right, the pistons are very similar in design being made by the same manufacturer.









The pin oil hole is an excellent addition as the stock piston despite its low milage has easily visibl friction rub in the area of the lube hole.

[This message has been edited by Joseph Upson (edited 03-06-2009).]

Bump... Any more info on the production of the 270 HP engine?

Just a bump to keep this thread alive a little longer for some more pertinant info to add. Since the engine has been installed and tested a little, I've discovered that the best use for VVT in a retrofit using earlier ECMs is to install the cam advanced by a measured 10 degrees and after about 4000 rpm have it retard to the recommended install angle for the cam grind. From what I've read retarding a cam beyond 0 deg is not as sure a performance gain as advancing a cam although that would favor bottom end performance. The fully advanced position offers a good bit more additional bottom end torque for low speed driving as well as fuel economy and can easily be retarded at a specific rpm afterwards to maximize peak output.

I just shipped out a 3900 cam to have reground for more bottom end torque, since the VVT allows the stock cam a hp peak at 6000 rpm, there is no sense in having the cam reground for more top end performance when my turbo choice is going to shift the peak output a few 100 rpm passed that point, as I've already discovered with the current cam that was reground in error for more top end performance on a cam spec that already provides it.

Proof of this was realized in performance with the cam fully retarded vs. fully advanced, with the cam retarded it would chirp the tires going into second gear because the torque peak had been shifted higher in the rpm range and rpm would be elavated at that point. When the cam was locked in the full advance position I could no longer do that with ease although it did tend to chirp the tires on take off on occasion more easily.

The fuel economy with the cam fully retarded was terrible however part or all of that may have had to do with the increased duration of the regrind coupled with the cam being retarded. With the cam fully advanced the fuel efficiency was exceptionally better and went from nearly being able to see the fuel needle move toward empty to holding its position for quite a while characteristic of what I was used to with the smaller engine.

Although there are provisions to convert the engine to a non VVT camshaft with cam bearing sleeves, I believe the stock camshaft with its apparently broader cam lobes along with a regrind is the best approach regarding the camshaft. Blocking the cam phaser into a specific degree angle for non VVT use is a pretty simple process.

bump. keep it going

quote Originally posted by Lou6t4gto: bump. keep it going

Wrong thread, search for the thread with the engine installed for the picture of the iron head with the aluminum head rockers installed on it.

do you remember exactly What the thread was Called ? Thanks

quote Originally posted by Lou6t4gto: do you remember exactly What the thread was Called ? Thanks

https://www.fiero.nl/forum/Forum2/HTML/084972.html