befu

iTrader: (2)

So how do you tell what bell housing you need? Part number and or description of what to look for? They must have started using them in the late 80's I would think.

87MagnumII

There is only a fractional amount of difference on the inside but it's enuff to matter.you can tell by looking at the outside tho The old style is rounded where it "bells" where the flywheel spins. The new style that you need is more flat on top of the "bell", kinda squared off almost. It's slight difference but you should be able to tell if you can picture what I'm saying

befu

iTrader: (2)

OK, here is three pics of mine. The one you can see the opening for the coupler is smaller than the opening of the one they currently sell at michiganmotorz.com, so I am figuring I have the wrong type for a triangle coupler? My coupler definately looks like a donut (kinda).

Brian

befu

iTrader: (2)

OK, first one is the one on motorworkz.com

The three vertical holes on the right side are all on one flat surface where mine are all on different steps. Also, the coupler opening is almost as large as the rear mounting lugs. The last picture of mine does not look like this.

This is a 865657A03


I think this is the one I have, smaller opening. Part number 8657A04. Sound right? So I am guessing I will need new bellhousings, correct? What about the Alpha input shaft, is that the same or do I need a new input shaft for the new triangle coupler as opposed to the donut coupler?

sprink58

The input shafts are the same for all the couplers that I have tried, Alpha triangular, Alpha Do-nut and Bravo. The only one that I have seen that is different is th Bravo XR that has different splines.

Also...this write up from http://www.gmpartsdirect.com/perform...CATID=883.html goes a long way in explaining that 1986 was the change over year for the one piece main seal. This is why I thought if you did infact have '86 blocks you would be ok. Educational reading:

SEAL DEAL
Production small-block V8 and V6/90-degree Chevrolet crankshafts were redesigned in 1986 to use a leak-resistant one-piece rear seal. The diameter of the crankshaft flywheel flange was reduced to fit this new seal. The engine block, oil pan, pan gaskets, and flywheel were also redesigned to accommodate this one-piece seal.
Crankshafts designed for one-piece seals have a smaller flywheel bolt pattern than pre-1986 production cranks. All small-block and V6/90-degree cranks which use a one-piece seal require a counterweighted flywheel for proper engine balance.
Unmachined crankshaft forgings and most heavy-duty crankshafts (except P/N 14096036) use pre-1986 two-piece rear seals. These cranks can be installed in late-model blocks which are machined for one-piece seals by using crankshaft seal adapter P/N 10051118.

In reading this I think that '86 flywheels or later may work with the later Vortec engines. I can't find any thing that indicates that there was a change in the flywheel/crankshaft seal arrangement when 5.7 small blocks were changed to Vortec in the mid '90's.

Also...are your engines L31 5.7's or are they 6.0's...just curious.

I got this from Wikipedia: http://en.wikipedia.org/wiki/GM_Vortec_engine

5700
[edit]Generation I
The Vortec 5700 L31 is a V8 truck engine. Displacement is 5.7 L. It is the last production Generation I small-block from Chevrolet. The cylinder heads feature combustion chambers and intake ports very similar to those of the LT1 V8, but without the reverse-flow cooling. As such, the L31 head is compatible with all older small-blocks, and is a very popular upgrade. It offers the performance of more expensive heads, at a much lower cost. It does, however, require a specific intake manifold (a Vortec head has 8 bolts attaching the intake manifold as opposed to the traditional twelve bolts per head). The L31 was replaced by the 5.3 L 5300 LM7. The 2002 model year was the final year for the L31 5.7 L small block V-8 whose origins date back to 1955. The Vortec 5700 produces 255 hp (191 kW) to 350 hp (261 kW) at 4600 rpm and 330 ft-lbf (448 N•m) to 350 ft-lbf (475 N•m) of torque at 2800 rpm. It is currently being produced as a crate engine for marine applications and automotive hobbyists as the "ramjet 350" with minor modifications.
L31 applications:
1996–2003 Chevrolet Express/GMC Savana full-size vans
1994–1999 Chevrolet/GMC C/K full-size trucks
1996–1999 Chevrolet Suburban/GMC Suburban full-size long-wheelbase SUVs
1996–1999 Chevrolet Tahoe/GMC Yukon (and 2000 Tahoe Limited) full-size short-wheelbase SUVs
1999–2000 Cadillac Escalade
TBI L31 applications
1996 G-Series vans over 8,500 lb (3,856 kg) GVW w/ 4L80E transmission.

Let us know how this works out because I think we will see more and more of this as time goes on.

87MagnumII

Your coupler is the old style for a 2 piece main I believe. If you contact a member of oso screen name lennox60 he has the part numbers for the correct bell housing

befu

iTrader: (2)

So, my boat is 1986 Formula. The casting numbers seem to indicate one or both is a crate motor. The port one looks too new to be original, and the the starboard motor was bored 0.040 over so it is rebuilt. They are both two piece main seal engines. 14" flywheels with triangle couplers. The bellhousings are an older style, but work with the triangle coupler. Found a picture from moore that described the bellhousing that had issues with the triangle coupler, it is 82 and older.

So I have late 90's generation 1+ engines (1 piece main seal, vortec heads, roller cams) that I am building and putting in. I need the one piece main seal crankshaft flywheels for them. Have a line locally for them, will look at on Wednesday. Hopefully they are the 14" models. I can use the triangle couplers with my existing bellhousings. Going to need new mounts as mine look sad.

So I guess there are two very similar bell housings out there that will work for the triangle couplers. Hopefully I have this figured out by the end of the week what I have and what I still need. Liking that Michiganmotorz place, will have to call them later this week!

Brian
My parts:


Moore's picture

87MagnumII

Mine split the bell housing on the top when we tried to start it, I've never seen a triangular coupler like your either, it's kind of a cross between an old donut style and a new triangular style

dereknkathy

i take it you are planning on replacing the cams? the ones in those vortecs are designed for emissions first, last, and corporate average fuel econony in between.

befu

iTrader: (2)

Already have the standard mercruiser roller cam that the 295 - 300 HP engines have in them. Same as the HT383 and ramjet cam from chevy.

Getting aftermarket aluminum intakes also, stock exhaust.

Brian