GT6+ Buick V6 resurrection.

[Richard/SIA]

Just bought a poorly done GT6+ V6 shell from a local CL ad.
Very poorly done, big hole in the bonnet to clear the Turbo V6.
Looks like they also added spacers to raise the body, Mazda live axle conversion is too wide, chopped out the firewall, etc.

I bought it as a home for one of the several rebuilt Buick V6's I happen to have on hand, from 198" to 231".
All non-turbo.
My 225" is a particularly strong runner.

I'm thinking a T5 trans as I really do not need a Muncie in such a light car.
Could use some advice on weather or not Camaro T5's are really the issue some say they are do to an angled mounting in the Camaro?

I will try to post some pics of where I am starting from.

I have a basic question to start with.
Are the V6 and BOP/Rover motor mount pads the same as the V6?
I know the V6 derived from the V8 so hope they are the same.
I do not have a V8 handy for comparison.
Current frame mounts look like they were done for early type SBC engine mounts.
If possible I would like to move the engine further back.
I have a junk block for mock-up but need to finalize my transmission first.

V6 will be about double the original HP, I'm not after another Cobra Coupe clone so this will be sufficient.
V6 is only a little heavier but also shorter than the BOP V8 so it should end up a front mid-engine.

Originally I was going to do this to a Spitfire Mk. III I have but this should be a little better.

[Richard/SIA]

Well I just confirmed the first part I want to change.
The flywheel I have is 50#!

Want to get it down around 30# or less.
My SBC aluminum flywheel is 13#.

Web searches are fruitless, everything is for for Chevy or BOP V8.

I had a Weber V6 flywheel on the shelf for years in case I ever needed it.
Now that I sold it a couple of years ago during an ill advised "Clean up", I wish I had it back.

Anyone have a source for a lighter odd-fire flywheel?
A drawing for where to safely remove weight from mine?

Ah, found them at TA Performance and the price is not bad.
Edit for update, Aluminum around 15#, Steel 30#.

[Richard/SIA]

No room for the car inside right now so I decided I should begin with sorting out the 225 V6 engine issues.

It got pulled from a Hurst Jeepster Commando when it began spewing water from the back of the block one very cold night.
I assumed the block was cracked and I would have to rebuild the components into another.
Looking it over after removal no crack or displaced freeze plug could be found.
From the amount of water spewing from the block that night I expected to find a large chunk missing!

Tonight I pulled the top end.
It appears the head gasket may have blown at the very rear of the head at the rear water passage.
Still seems hard to believe the small gap I found leaked that much, but under pressure I guess it's possible.
I will have to strait-edge the block and heads before reassembly, hoping a gasket is all I need.

This engine ran very strong and now I have a better idea of why.
I did not build it so had not seen any internal details before now.
Edelbrock 600 and corrected jetting for my altitude.
Offenhauser 360 intake is gasket matched to the ported heads.
Light weight valve spring retainers, one coil and one flat  (Damper?) spring each.
Adjustable pushrods.
Flat-top pistons with a very shallow dish, no valve reliefs.
Cam lobes look fairly serious.
Long tube headers.
Guy I got it from told me it would do 7,000 RPM but I've never gone over 6,000 and that only very briefly.
Probably a good thing with the stock 50 lb. flywheel.
That flywheel probably had a lot to do with why this engine always seemed a bit sluggish to spool up but ran like a V8 once it got going.

I'm removing the carbon from the piston tops and combustion chambers.
I will CC the heads and piston tops to determine my actual compression.
Do not want to get into the engine too deep but may pull the timing chain in order to identify the cam.
Should probably touch up the valves and fit new seals while it's apart too.
I have all the pulleys and accessory mounts for this engine as it is so I think I will forgo efforts to make it even shorter.

I also have an unfired even fire 3.8 I pulled from a Porsche a local guys dad had racing plans for.
It appears virtually stock internally from what I have seen so far.
I may pull the heads from it too for a better look inside.
Seems odd he may have done so little to it.
Maybe a candidate for F.I. and forced induction since it is an even-fire engine?
It's my No. 1 spare if/when I blow up or wear out the 225.
This is the engine I might try to shorten using later model components.

[Dan Jones]

> Are the V6 and BOP/Rover motor mount pads the same as the V6?
> I know the V6 derived from the V8 so hope they are the same.

I think they are but I'll make a note to check.

> Cam lobes look fairly serious.

See if there are any markings on the cam.  With those, we might be able to figure out the cam specs.

> Long tube headers.

Are they 1 1/2" or 1 5/8" primary diameter?

> That flywheel probably had a lot to do with why this engine always seemed a bit sluggish to spool up but ran like a V8 once it
got going.

The Offenhauser 360 intake is also partially to blame for the sluggish performance.  It's basically an open plenum with minimal runner length.  We tested one on a different engine, along with e8 or 9 other intake manifolds and it was the worst of the bunch. Had the worst low end but and wasn't very good on the high end either.  One of the Buick V6 powered TR7 guys did a fair bit of intake and carb testing on his Buick 4.1L V6 (with Crane H-214/2867-12 cam and TR7 swap headers from John's Cars) and his opinion was the Kenne-Bell #1 Buick V6 4 barrel manifold was, by far, the best manifold available for the normally aspirated Buick V6. Unlike some of the other Buick V6 intakes, the Kenne Bell Number 1 has an intermediate port design and will fit either early or later Buick V6 heads.  He also found that the Carter/Edelbrock 500 CFM carb was better than the 600 and 625 CFM carbs on his engine.

> Do not want to get into the engine too deep but may pull the timing chain in order to identify the cam.

Check the timing chain for wear.  My 231 Buick V6 was pretty hard on timing chains.

> Should probably touch up the valves and fit new seals while it's apart too.

and do a wiggle check on the guides.

Dan Jones

[Richard/SIA]

Traded away a KB manifold a few years ago as it seemed inappropriate for a low speed trail Jeep.
Suppose I can look for another.
I have an Edelbrock performer but it will not fit the 225 heads.
Ports on it seem a bit sloppy, not well defined at all.

Need to figure out my engine mounts.
May be able to use the existing mounts, or may want to move them further back.
I have no idea what rubber mounts were used previously as they went away with the turbo engine I did not get.
I think I will try to strip my junk block to make it easier to handle.

[Dan Jones]

> I have an Edelbrock performer but it will not fit the 225 heads.
> Ports on it seem a bit sloppy, not well defined at all.

Most of the Buick V6 intake manifolds, including GM's 4.1L Buick V6 four barrel,
are single plane manifolds while the Edelbrock Performer is a dual plane design.  
It's a little odd that Edelbrock chose to go with a dual plane.  The dual plane
design was designed to compensate for the adjacent cylinder firing reversion
problem that non-flat plane crank 90 degree V8s suffer from.  Being a 90 degree
V6, the Buick doesn't suffer from that problem.   Offenhauser also made a
Dual Port Buick V6 intake.  The dual port design has the runners split into top
and bottom sections with the plenum split fore and aft (rather than the usual
side-to-side like the Equa-Flow 360).  It's essentially two single planes stacked
on top of each other with the primaries feeding the longer path lower runners and
the secondaries feeding the shorter path upper runners.  When cruising, the
manifold operates on the smaller diameter, longer path, runners.  This provides
high velocity flow for good fuel economy and throttle response.  Under high demand
the secondaries open and provide additional flow through the larger top runner
portion.  It's an interesting approach but the packaging required to fit within a
carb intake envelope does compromise the design.  By reputation, it's a good fuel
economy, low end response type intake.  David Vizard did a big intake comparison
on a 350 Chevy V8 which may or may not apply to the Buick V6.  Basically, the Dual
Port was near the bottom of the list when comparing peak horsepower but had decent
area under the curve and was the only intake with better specific fuel consumption
than the stock Qjet intake.  I ran a Dual Port on my Buick/Rover aluminum V8.  It
was smooth and ran well at low RPM but became restrictive at higher RPM.  I've got
another dual port (for a 351C Ford V8) that has been cut apart and ported to correct
some of the port-to-port variation.  We'll be dyno testing so it will be interesting
see how it compares to more conventional intake manifolds.

> Traded away a KB manifold a few years ago as it seemed inappropriate for a
> low speed trail Jeep.

The KB has smaller ports and longer runners than the Offenhauser 360 and has much
less runner-to-runner variation.  If you're focused on lower RPM, you might want
to try a smaller carb than the 600 Edelbrock.  

> Suppose I can look for another.

TA Performance supposedly bought the Kenne Bell Number 1 intake and plan to
reintroduce it.  I sold most of my Buick V6 stuff off years ago but I think
I still have a Kenne Bell intake.  IIRC, a local TR7V6 guy wanted it but never
followed through on the sale.  I can look for it if you are interested.

Dan Jones

[ghornbostel]

very interesting....keep talking about this V6 Buick stuff guys, I'm listening.  

Regards
Greg Hornbostel

[Richard/SIA]

Hurst Jeep needed low end, current GT-6 project does not.

Interested in the KB manifold even if I get the one I may have found.
I have a few of these engines, even an old 198" odd-fire.

Going to replace some of my books that seem to have wandered off.
Not looking to build any more of these soon but might later.
For now I may just tweak some I already have with different cam, heads, manifold, or at least identify what has been done to them so far.
Pretty certain one 3.8 is bone stock, the one from the Porsche is a big ?
Sometimes these can be bought with zero miles cheap, why I ended up with so many.

[BlownMGB-V8]

Being so similar to the SBB there is a lot of overlap between the two. Naturally most of the oiling mods are the same for instance. One recommended combo is the stock 4.1 intake and carb. I don't know how good it is by comparison with the aftermarket stuff but it seems to be popular.

That Offy DP intake was a bit of an odd bird. I used one of those as the base for my heatpipe intercooler/blower 215 build by taking out all the port dividers, opening up the top and removing all the dual plane stuff. It ended up having just a HUGE plenum cavity which I stuffed half of the heatpipe into, and then these really short runners. Worked for my application but it seemed to me that as a street manifold it was pretty limited and I never noticed it helping any with the mileage or driveability. But then again, odds are I had it on a very low compression engine so who's to say?

Jim

[Dan Jones]

> Interested in the KB manifold even if I get the one I may have found.

I'll look this weekend and make sure I still have it.

> Going to replace some of my books that seem to have wandered off.

The literature I found most useful for the normally aspirated Buick V6 was the
Buick Stage One V6 Performance Guide by Jim Ruggles, a Hot Rod magazine article
on Smokey Yunick's 5-step plan for the Buick V6, the Kenne-Bell catalog and tech tips
and the S-A Designs V6 Performance book.

> One recommended combo is the stock 4.1 intake and carb. I don't know how good it
> is by  comparison with the aftermarket stuff but it seems to be popular.

The Hot Rod article on Smokey Yunick's 5-step dyno test tested the 4.1L intake
and QuadraJet carb:

 4.1L Buick V6 with stock 4 barrel intake and Qjet carb   152 HP
 Weiand intake manifold and Holley 600 CFM carb           170 HP
 Weiand headers                                           175 HP
 Crane H-214/2867-12 cam                                  202 HP
 Bowl port heads                                          230 HP

The Weiand is similar to the Kenne Bell single plane but has an adpater that allows it
to mount up a Quadra Jet spread bore carb.  The Ruggles Guide also has some dyno test
results but be aware the 4.1L intake only fits the 1979 and later Buick V6s with the
taller port heads.

> That Offy DP intake was a bit of an odd bird. I used one of those as the base for my
> heatpipe intercooler/blower 215 build by taking out all the port dividers, opening up
> the top and removing all the dual plane stuff. It ended up having just a HUGE plenum
> cavity which I stuffed half of the heatpipe into, and then these really short runners.

Starting the the Offy Equa Flow 360 would have been a lot easier.  External the Dual Port
and Equa Flow are the same casting but the Equa Flow is just a big plenum with a side-to-side
divider.  Just mill ount the center divider.  Very popular for mounting Roots type
superchargers.

Dan Jones

[ghornbostel]

Well now, it looks like all the known V6 Buick info is starting to surface again along with some up to date experience with manifolds and headers.  My engine is an evenfire, a 1980 to be exact as I bought the car new.  I had at one point thought about using a 1962 engine to appeese the vintage race gods but after reading through what is available could see no reason to do so as these people are of the mind set that no one but a Carrol Shelby could have done anything like that in 1962.  Anyway, this engine has had a lot of good money thrown at it.  In its final stage 2 form it would probably peel the paint off most fast cars on the street today.  The production line version (in its final form is what I understand is the 109 block) is really a marvel but for a mild street engine a block from anything from 1979 to 1987 (evenfire) is acceptable.  I'm trying to keep this affordable.  Turbo crank and 2 dot rods are good and if you want more compression (for us NA people) find a set of 350 Buick pistons and have the pin area widened for the V6 off set.  Cams, you really need some help here to get something that works with your engine. Heads 8445s if you want the latest.  Headers, here's where I find very little information other than mention of the Smoky headers from Weiand.  I have a set of these and they are simply 1 5/8 tubes about 10" long merging into a 2 1/2 collector.  Headers by Ed sells both a 1 1/2 and 1 5/8 inch header flange and this site states V6 (and makes no mention or make) 1 1/2 primaries 38" long into a 2 1/8" exhaust system.  Information on that site is very interesting.  I'm not sure if I can get 38" of pipe under my TR3 but will look into it.  This is the direction I'm going in and as the sign states "don't follow me, I'm lost" but I'm not too proud to ask for directions.  All this confusion sure makes this a lot of fun.  Just about any engine will fit into just about any car but are we going to be able to live with the result.  

Regards
Greg Hornbostel

[Richard/SIA]

I am using my odd-fire 225" to start with.
It's a fairly warm engine that did a good job of getting a heavy Jeep moving.
In the GT-6 with a light flywheel it should do very well indeed.
Hoping to grab a T5 in the next couple of days.

Not looking for all the power possible as I do not want to be forced to go to "Pro-Street" levels of fabrication and mods.
V6, T5, and an answer to the rear axle question should be enough to make me happy with this one.
Working with what I have laying around as much as possible.
It's never going to be a total sleeper but I do hope to minimize visible mods.
Well, except for the currently planned side-pipes and air scoop. ;-)

[mgb260]

I've had 225's and 231(3. V6's in various vehicles, one of my favorite motors. In my CJ5  I originally put in a 225 out of a 64 Special and replaced it with a  82 231 with a Offy dual port intake, Carter 400 AFB ,Kenn-Bell cam and headers. I later put that motor in a Vega and a 215 in the Jeep. I like the 215, it is just too small. The 231 was much snappier. I read somewhere where they took 3.8 Ford V6 stock shorty headers and cut the flanges off and made Buick flanges. That 225 flywheel is way too heavy.

[Richard/SIA]

In a bit of a hurry to sort out major parts for the GT6.
Seems a Mazda Miata rear may be a fairly easy swap?
Maybe put an RX-7 diff in it?
Anyone here familiar with them, or their strength - weakness?

I want to retain IRS, might run the GT6 in our local hill climb event.

I will be using an about 200 HP Buick 225 V6 and T5 to begin with.
Might put an about 300 HP 231 in it some day.

Mazda Miata and RX-7 rears are still pretty easy to find in junk yards.
Miata may be close enough in width?
Also saw some references about some years being stronger than others.
Of course late model parts are only available from the expensive wreckers.

UPDATE; Miata rear is still a little too wide at 56.2"
Simpler to go live axle and maybe update later.
Looking at an Alfa axle now as the width is almost perfect and it has disc brakes.

[Richard/SIA]

Verified that the T5 is a WC unit.
GM used the T-5 in F-body cars behind all engines.
In general, the I4/V6 got the following ratios: 1st – 3.50 2nd – 2.14 3rd – 1.36 4th – 1.00 5th – 0.78

From here I will want to figure out my desired axle ratio.

The Alfa live axle rear may be a little marginal.
But it's also fairly cheap with LSD and disk brakes.

Really prefer IRS but also want to drive it THIS year.

[roverman]

Richard, Doesn't the heavier flywheel cancel-out some of the inherent gallop/harmonics, of the the odd fire ? Most of the Yunick and Ruggles work, was with even-fire engines= more airflow and smoother running.Second most plentiful engine built by GM, after the sbc. This means plentiful/cheap, even-fire engines and parts.  Cheers, roverman.

[Richard/SIA]

The odd-fire 225 I have is a known strong runner so I will use it while it last.

As posted I also have two rebuilt and unfired 231's as spares to drop in if needed or for other projects.
Trying NOT to take on more projects as I have enough now to last the rest of my days.

I don't mind the "Odd" firing spacing.
An aluminum flywheel and better intake should let it rev nicely.

My daily driver is a loud 11-1 comp. very lumpy - no vacuum cam, headers and double pumper 700 carbed 350 v8 in a 1968 El Camino.
Just got a Muncie to put in it.
Rather drive it than some newer Nader-mobile blessed by the "Green" cult.
Most of my cars have a similar flavor, fickle finger of fate to those who wish to rule me rather than leave me free.

The GT6 will not be my fastest car but should be fun.

I passed on the T5 trans for now.
Since the number tag is missing it's going to be a chore to confirm the gear spread.
I am now told that the Camaro V6 3.50 first is rare, and all the other likely first gear ratios are worse.
Hoping I can just grab another Muncie somewhere, an M21 with any luck.

[roverman]

"Passed on the T5", Just put it in first gear, mark the input/output, and count the turns. Once you figure first gear, the internet will likely tell you the other ratios. A 3.50 first, will likey be pretty useless, with your current RE ratio ?  Cheers, roverman.

[Richard/SIA]

Have a line on a Muncie M21, if the seller would just answer his email.
He thinks it's an M22 so may be resisting reality.

My rear ratio can be set later as the current unknown live axle is coming out.

[Richard/SIA]

Did some cleaning up during the weather break.
Very little rust, only a very small hole in the tire well area.
Too bad they hacked the car so bad.
I need to cut the firewall and part of the floor from a junk car for repairs to this one.

Found a few extra spare parts, and some that I will need.
Also realized that I am replacing the original six with another six, so may be able to get the original tach to work!

I also found an ironic book in the boot, "Triumph Spitfire and GT6" a guide to originality, by John Thomason.

[Richard/SIA]

Did some more disassembly.
Got the body bolts and gas tank out.

Hard to believe ANYONE could do such shoddy work.
Every body bolt is wrong since they had to be replaced to put extra spacers between the body and frame so the tires would not rub the wheel arches.
Rear tires stick out both sides of the car since the axle is too wide.
Guess I should be glad they did not just hack the rear fenders!

I'm thinking I am going to have to create my own IRS rear pretty much from scratch.
I want to get the body off so I can see what has been done to the frame to mount the current live axle.
From what I see so far it probably does not have any actual rear suspension since various bars move in conflicting planes of motion, and at right angle to each other as well!
Any movement would have to be by flex in the components and brackets.

So the major questions of the moment become.

1. Any working drawings out there for a 50" wide track IRS that will handle 250 - 300  HP other than early XKE?
Would like to keep it much lighter than a Jag rear too.
Looks like the rear suspension may be the hardest part of this build.
Going to that much effort I guess rear disc become a given.

2. Chassis reinforcement other than a full roll cage?
I have thought about adding some perimeter tubing but suspect that is better for side impact than actual chassis stiffening under cornering load.
Do not want to add any more weight than absolutely necessary, have gone so far as to consider using hollow bolts where possible.

Just to be non-PC, and since it's a cheap way out, considering a "Spitfire" camo paint scheme.
Did it once before to help hide severe body damage on a beater Spitfire.
Got lots of comment from folk old enough to recognize what I had done.

Samples,
http://forums.pelicanparts.com/uploads18/2843700589_68ebfc07891281632078.jpg

http://forums.pelicanparts.com/uploads18/JGarrison21281632094.jpg

[Dan Jones]

> I'm thinking I am going to have to create my own IRS rear pretty much from scratch.

You may want to look into what the Cobra kit car companies offer.  I've driven and wrenched on both a Superformance Cobra and an ERA Cobra.  The ERA Cobra had the Jaguar-based IRS while the Superformance Cobra had a Ford 8.8" based IRS.  I found the the Superformance handling was much better than the Jag-based ERA.  I believe the Factory Five Cobras also have a Ford 8.8" IRS option.  A quick search shows 54" (narrow) and 59 1/4" (standard) hub-to-hub widths for the Factory Five IRS.  It appears the Factory Five standard width was driven by the need to match the standard Fox body Mustang solid rear axle width so perhaps the Superformance will be narrower.

Dan Jones

[Richard/SIA]

Spitfire/GT6 rear track at 50".
Do not want to flare the fenders.
Not finding anything that narrow even in a live axle.

Poking around the web it seems some Corvair parts have been used in the past by racers.
Need to find some time at a junk yard to look around and take measurements.

Hazy idea at the moment for a Franken-rear of Supra center, Corvair hubs re-drilled to GT6 pattern, and or fabricated uprights.
Need to take a look at Fiero since they already have disc brakes and are plentiful.
Make my own A-arms.
Coil over shocks.

Needs to be good to around 250 HP - 300 HP tops.
Also want to keep it reasonably light.

Narrowed Jag would be the least expensive but not sure there is room for the cast hub carriers.
Need to get my hands on some original components for measurements.

A late night update.
Found some great pics of Fiero rear suspension uprights modified to use an upper A arm.
LONG thread with CAD drawings here, http://www.fiero.nl/forum/Forum3/HTML/000116-16.html
I am not interested in the rocker shocks and his drawings will not directly work for my use.
I probably have to build a sub-frame at the rear of the GT6 but with the body off that should not be hard.
I hope to be able to leave the wheel wells alone.
This may be a way to keep a budget build while also getting much improved rear suspension geometry and brakes.
Since I want to keep 13" wheels I expect to retain the original Fiero calipers.
Much more research to do, hoping to visit a junk yard this week with some calipers and digital camera in hand.

[mgb260]

Richard, Check out my old thread on using a Toyota 4X4 IFS for RWD. Using the Toyota short CV axles with Chevy Cobalt stub/outer CV for 4 lug or Dodge intrepid  5X4.5 for 5 lug.

http://forum.britishv8.org/read.php?3,22861

[Richard/SIA]

Had a look, now questions.

What HP and torque will that handle well, and do you have any physical dimensions?

Looks like a single point mount at the rear and two tapped on the nose face the top?

Might be a good unit to fit between Fiero outer hubs?