Why aren't people doing a 2.9 V6 swap?

[260Alpine]

Dan, my question on the oil pump driveshaft. Do you have a 2.9 (Torx) and 2.8(Hex/Allen) to compare for length?

 

[Barry]

Barry, I will get these different measurements between the 2.8 early/late, 2.9 and 4.0 this week.

Part of the question is where you should measure from. Maybe from the front face of the engine blocks?

 

[DanR]

The historical conventional wisdom was that the 2.9 / 4.0 exhaust port layout was incompatible with the Series Alpine steering system and it seems to me that the front accessory drive length issue was pretty much ignored. Recent events (i.e.; DanR's prototype 4.0 headers), suggest that the conventional wisdom may have been wrong, but only a car on the road will settle the issue.

As I have stated before, Thanks for the motivation.

It was said the 2.8 Siamese exhaust ports were the "only" options for the Alpine application. After my 3 year struggle to build the Straight Back Headers, I took on the task of implanting the 4.0 OHV V6. Bought a used engine, bolted it to the mutt II Bellhousing and a T5 , sat this assy in my early SIV GT BW35 and decided to make the impossible happen.

It was said also that you would have to butcher the Alpine, change the steering to a rack&pinion, etc., etc.,

I utilized the current 2.8 engine mounts and tranny bracket. Except for the top engine mount on the RH side, the bolt pattern was slightly different. I have discovered there is also a difference in the bolt patterns on the different years of the 4.0's too. More on this later.

When I first started, I had my doubts, but, I ordered a batch of exhaust tubing, bends, elbows, and donuts and started the "cutting&pasting" for a set of straightback headers. I started on the drivers (LH) side next to the steering box because that was said to be the culprit for fittin the 4.0.

After a couple weeks and alot of snipping and tac'n I had a nice left bank header. Now, I was ready to do the easy side(RH). To my surprise it was much more difficult. It too turned out to be very nice.

I used the same crosslink I designed for the 2.8. It provided sufficient clearance behind the heads and valve covers, exactly as the 2.8. PIC's of the headers and the steering box depict a distinct difference between the 2.8 and the 4.0 exhaust port arrangement. The staggered ports of the 4.0 allow more spacing around both sides of the Alpine steering box, specifically ports for cylinders 5 & 6.. Unlike the 2.8 Siamese ports 5 & 6 with 6 near bumping the steering box.

I toyed with the stock FI as the fuel system, but did not like the high profile look. Searched the net for some other system. Found a special designed 4bbl intake that looked too big and bulky with lots of unknowns of its' functional qualities and it was rather expensive. If I was to make this thing work for myself and possibly others, it was to be fairly low cost. Surely didn't want it to be above the$2500 -3500 range.

With lots of support from fellow SAOCA Members my dream kept expanding. The fuel system is still experimental.

I contacted a MicroSquirt Rep to build a system for the 4.0 OHV V6 right at the same time the Covid hit us. That is still something I'd like to see accomplished. I have a complete Explorer with the 4.0 OHV V6 5 speed that is running to use for development of the MicroSquirt. Several months ago, I was able to get a shop to agree to do a 4bbl intake for the 4.0 OHV V6. It is near finished, looks good. There will need to be a distributor modified and some other stuff to make this doable.

At present, the 2.8 V6 is perfect for the Alpine.

 

[DanR]

Dan, my question on the oil pump driveshaft. Do you have a 2.9 (Torx) and 2.8(Hex/Allen) to compare for length?

I don't have the 2.9 shaft. Will find one.

 

[DanR]

Part of the question is where you should measure from. Maybe from the front face of the engine blocks?

I would start with the front face of the engine blocks. I have the three (3) 2.8/2.9/4.0 engine blocks.

 

[Bill Blue]

As I recall, Jim Ellis crammed a 2.9 crank into his 2.8. He had to machine the snout of the crank to do so. So I guess it is a case of bad news - good news. The bad news being the crank needs machining, the good news there is ample meat in the crank. With overbore and the 2.9 crank, he no longer had 2.8 displacement. It would be 2.9+. Probably close to 3.0.

Bill

 

[Barry]

As I recall, Jim Ellis crammed a 2.9 crank into his 2.8. He had to machine the snout of the crank to do so. So I guess it is a case of bad news - good news. The bad news being the crank needs machining, the good news there is ample meat in the crank. With overbore and the 2.9 crank, he no longer had 2.8 displacement. It would be 2.9+. Probably close to 3.0.

Bill

Good memory! Putting a 2.9 crank in a 2.8 block requires more than just machining the snout of the crank. At the very least, it also requires using 2.9 pistons with a lower piston compression height. I suspect that the 2.8 block would also have to be "clearanced" for the longer stroke 2.9 crank. IIRC, Jim used +1mm 2.9 pistons which would have been about 2998 cc.

 

[Bill Blue]

about 2998 cc.

Close enough!
Bill

 

[DanR]

Here's some figures on the 2.8Early and Late), 2.9 and 4.0 OHV V6's:
Face of Timing Cover (TC) to Face of Water Pump (WP) length:
2.8 3"
2.9 4" (Note: Has screw on fan hub .66" for threads)
4.0 4 1/8" (Note: Has screw on fan hub 5/8" threads)

Face of TC to Engine Block (EB) length:
2.8 1.984 inches or 50.00mm
2.9 1.848 inches or 46.95mm
4.0 2.042 inches or 51.87mm

As an added note the Harmonic balancer diameter (s) for:
2.8 144.36 mm or 5.68 inches
2.9 Same as the 2.8
4.0 152.48mm or 6.00 inches

NOTE - ADDITIONAL MEASUREMENTS:

2.8 Early Block to flange on water pump = 4 and 7/8"
2.8 Late Block to flange on water pump = 6 and 1/8" + threads on end are 5/8"
2.9 Unknown at present
4.0 Block to flange on water pump = 6" plus 5/8" threaded end for fan mount

 

[Bill Blue]

Dan, any info as to which 2.9 parts will bolt onto the 4.0 and would it add enough space?
Bill

 

[Barry]

Dan,

The problem with the 2.9 and 4.0 engines is the overall length, so it seems to me that the "mounted length" of the various damper / pulleys is at least as important as the diameter.

 

[DanR]

Basically there are none other than possibly valve covers and the Harmonic balancer to my knowledge.

The heads are angled different from the 4.0. There are differences in the intakes too. Widths, lengths &angles are very distinct. The blocks are same lengths.

I am trying to find timing cover and water pump gaskets for the 2.9.

I have complete 2.9 and 4.0 engines. 1 new reconditioned 2.9 block (bare). Would like to find a timing cover for the 2.9. Don't want to take down the complete engine I have , yet....

 

[DanR]

Dan,

The problem with the 2.9 and 4.0 engines is the overall length, so it seems to me that the "mounted length" of the various damper / pulleys is at least as important as the diameter.

I thought of that too. Just failed to get the measurements..... will do

 

[Barry]

Just for grins, I made some measurements on the GM L32 3.4 V6 in my S-V.

My S-V engine bay is about 25-1/2" from the upper firewall to the back side of the radiator core.

The back face of the L32 engine block is about 1-1/2" forward of the upper firewall. The engine could go a little further back, but I left room for a distributor if I wanted to go that route and the 13-52-245 T-5 transmission mounting "foot" is already off the back of the V6 Jose transmission mount.

The L32 engine block is about 17-1/2" long and that includes the timing chain case. AFAIK, that dimension is the same for all GM 60-degree pushrod engines.

The diameter for both the damper and the crank pulley is about 6" and the front of the crank pulley is about 4-1/2" in front of the front surface of the engine block. From the back face of the block to front of crank pulley is about 22". The front of the crank pulley is completely behind the top of the S-V front suspension crossmember and the bottom of the crank pulley is about 1/2" above the pinchweld flange of the crossmember.

The front of the water pump shaft is about 5" in front of the front face of the engine block. From the back face of the block to the front of water pump shaft is about 22-1/2".

There is about 2-1/2" between the front end of the water pump shaft and the back face of the S-V radiator core. The L32 engine was only used in the '93 to '95 Camaro and did not use a water pump mounted fan, but one could easily be mounted. The L32 engine has a serpentine belt setup, so the water pump is "reverse rotation."
​

Offered as information, nothing more.

 

[husky drvr]

Barry,

Some quick questions:

Are you using the T5 tilted or straight up? If straight, how?

What is the approximate starter position (clock - viewing rear block face)?

Have you figured out how to work past the trans mount issue?

Just curious, sounds interesting,

 

[Barry]

Don,

The GM 60-degree pushrod engines have the starters on the right side of RWD engines and the opposite side (left ???) of FWD engines. The L32 is a RWD engine which means the starter is on the right side. FWIW, the starter is the same "staggered-bolt 168 tooth" starter that has been used in a gazillion SBC powered vehicles.

The 13-52-245 T-5 Camaro V6 transmission is currently installed in the tilted position (17 degrees to the left). but that is a function of the transmission bolt pattern in the Camaro V6 bellhousing being tilted. T-5 transmissions in 60-degree pushrod GM V6 trucks were mounted "straight-up" and the bellhousings are interchangeable. For that matter, the Camaro V6 bellhousing can be re-drilled. Note that the transmission mount foot on the 13-52-245 T-5 is also tilted 17 degrees to work with a normal "flat" transmission mount.

The V6 Jose transmission mount issue is not a big deal; just a piece of 3/16" plate to extend the mount back about an inch.

The iron-head L32 engine seemed like a good idea at the time, but the later splayed-valve aluminum-head FWD engines such as the 3.5 LX9 and the 3.9 LZ9 offer a lot more HP with a lot less weight if you are willing to go with EFI.

Unfortunately, the GM 60-degree V6 engines have almost exactly the same deck height and exhaust port location issues as the Ford 4.0.

HTH

 

[Bill Blue]

I would suggest that any
gm V6 installer not use the tilted trans setup. Creates a very wide transmission tunnel.

Bill

 

[DanR]

The Silver Alpine had a GM V6 when I bought it. Headers were a major problem along with the need to have a rack and pinion replacing the stock Alpine steering. The way it was mounted required a modification for the radiator too. The tunnel was modified differently from the Ford V6. My PICs are all gone, I think. Can't remember if the GM V6 had a front sump oil pan?

 

[Barry]

I would suggest that any
gm V6 installer not use the tilted trans setup. Creates a very wide transmission tunnel.

Bill

Bill,

I disagree about a "tilted T-5" in a Series Alpine creating a very wide transmission tunnel.

I first modified the trans tunnel in my S-V for a vertical T-5 installation. The same modification as for a vertical T-5 behind a Ford 2.8; that portion of the tunnel alongside the gas pedal had to be moved outward / left by about 1". The exterior dimensions of GM T-5's are no different than those of Ford T-5's. When I subsequently installed the "tilted Camaro" T-5, no additional modifications were required other than very minor trimming at the back of the tunnel around the "shifter box." Note that the transmission rotates around the axis of the upper mainshaft as it is tilted; the top of the trans case barely moves laterally and the bottom of the transmission case moves to the right where there is plenty of room at the bottom of the Series Alpine transmission tunnel. I prefer the vertical transmission arrangement, but in my experience, the tilted arrangement does not create any issues.

Perhaps my original tunnel modification was excessive or perhaps my engine / trans is installed lower than some others. As noted in a previous post, the damper / crank pulley in my installation is behind rather than above the front suspension crossmember.

Just documenting my experience with the tilted 13-52-245 T-5 behind a GM L32 V-6 installation in my S-V. No two Series Alpine V6 conversions are the same, so ...

 

[Barry]

The Silver Alpine had a GM V6 when I bought it. Headers were a major problem along with the need to have a rack and pinion replacing the stock Alpine steering. The way it was mounted required a modification for the radiator too. The tunnel was modified differently from the Ford V6. My PICs are all gone I think. Can't remembr it the GM V6 had a front sump oil pan?

Dan,

As I noted in a previous post, the deck height and exhaust port locations for the GM 60-degree pushrod V-6's are essentially identical to the Ford 4.0. If it is not necessary to use R&P steering with the 4.0, then it should not be necessary to use R&P steering with a GM 60-degree pushrod V-6. I did not like the extremely tight bends that were necessary for the primary tubes to clear the Series Alpine steering, but you have shown that it can be done.

As I noted in a previous post, the L32 engine in my S-V could be moved further back and there is still about 2-1/2" between the front of the water pump shaft and the back face of the S-V radiator core. No modification to the radiator was required.

The trans tunnel in my S-V was modified the same as for a T-5 behind a 2.8; that portion of the tunnel alongside the gas pedal was moved about 1" to the left. The exterior dimensions of GM T-5's are no different than the exterior of Ford T-5's, so ...

AKAIK, all RWD GM 60-degree pushrod V-6's have rear sump oil pans, but that is a non-issue. In my installation, the engine would have to be moved forward by at least 4" for the oil pan to interfere with the back of the front suspension crossmember.

Just documenting my experience with a GM 60-degree V-6 installation in my S-V. No two Series Alpine V6 conversions are the same, so ...