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Discussion Starter · #1 ·
I HAVE A BUICK 3.8 V6 ENGINE AND AUTOBOX FITTED IN MY 53 CHEVY TRUCK, THE GUY I BOUGHT IT OFF WAS UNSURE WETHER IT WAS ODD OR EVENFIRE, WHICH DIDN'T MATTER TO ME ANYWAY, HE ALSO TOLD ME THE
CARB WASNT TO GOOD, MY MATE AND MYSELF HAD IT RUNNING AROUND
CHRISTMAS TIME BUT IT KEPT FARTING AND BACKFIRING THROUGH THE
CARB, AND CATCHING THE CARB ON FIRE, I HAVE TWO OTHER ENGINES SO
WE BUILT ONE GOOD CARB OUT OF TWO, I FITTED THE CARB TODAY AND IT
HAVE CURED THE FARTING AND BACKFIRING, ACORDING TO THE BLOCK NO WHICH SAYS THIS ENGINE CAN BE EITHER ODD OR EVENFIRE , ALL
POINTERS SAY ITS A EVENFIRE BECAUSE THE DISSYS AND THE ENGINE
MOUNTS ARE EVENFIRE ONES, BUT IT RUNS BETTER WITH FIRING ORDER
165432 ODD, BUT SHOULD BE 145632 EVEN, HAVE ANY BODY ANY MORE
SUGGESTIONS . TIDDYTIME.:lol:
 

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What year is the blocK listed as ,1977? Is the timing mark on the case bolted on or cast into the cover.? My mate has an almost new Rochester that he bought for one of these that could be for sale. Depending on the year ( and heads you have ) he has a Weiand manifold for a 4 barrel, never used which he may sell :)

Dizzy cap can be confusing as they can still be offset inside even when the spacing on the cap is even :shake:
 

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Discussion Starter · #3 ·
odd or evenfire

The engine no is 1254083 which should be 1977-78, i,m wondering
weather somebody have rebuilt it with oddfire crank and cam or possibly a cam, data says odd and evenfire of this year can be
either, block no's and head no's will be same but cranks should
have different no's for odd and even, complete dissy is a lot different for both engines, odd has short and long segments
inside cap and dissy inners are different ,tiddytime.
 

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Yup, my mates is a '77 which can be used for either . His is rebuilt as an oddfire . If it has a repacement or performance cap they use evenly spaced posts but the tangs inside are different.

The crank has stepped big ends on the even fire but standard shared journals on the oddfire, we've one of each here .

If the engine hasn't been taken apart the timing mark on the chain cover has a cast in timing mark on the oddire and a bolt on plastic timing mark on the evenfire.

You wouldn't be able to use a mix of cam to crank as the lobe centres are very different, something like 22 degrees from memory.

Both his oddfires came with the larger HEI dizzy .

Even the oddfire he has in there now is a mix of parts ,that's when we spotted the timing cover was incorrect when we were going though it as it's fully rebuilt but hadn't been run .

I thought the firing orders were the same , just the spacing between pulses that changed ? I certainly don't remember changing the firing order when we has an even fire in there for awhile?

The dizzy is arranged as 3 pairs of 2 internally and it can be getting it on the correct lobe to start with ie the first post of the first pair that is critical .It means you can't just move the terminals round one to make it work . I'l see if I can find the tech page that explains it all .
 

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Discussion Starter · #6 ·
update

All three engines i have all have got the bolt on timing marker,
aparently , the one in the truck supposed to be evenfire block no,
1254083. 1977-8. An oddfire in workshop block no 1249432 , 1975-6.
And a second one in workshop block no1261438, evenfire. Year not
known, but surely if i take the rocker covers off and turn the engine manualy through its firing order from no 1 on tdc it should tell me the correct firing order, i know the oddfire
timing is more complicated, i have a step by step instructions
that i downloaded off internet a while back, so if it is oddfire
engine will it do any damage trying the oddfire dissy complete
to see if it runs any smoother, p.s will be interested in how much your mate wants for the parts, but reason for going for this
setup was for economy over a v8 as it is going to be a daily
runner. Cheers for help, tiddytime.
 

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Where did you get the other firing order from as both the odd and even fire have the same firing order which is 165432 ( I just checked as I didn't remember altering the leads on my mates )? The 'oddfire ' refers to the spaces between firing ie 90 and then 150 degrees as opposed to the 120 evenly spaced of the evenfire.

All they did when they introduced the evenfire was split the crank journals so all pistons arrive at TDC at the same time ( even though the pistons are then not centred over the crank). They coupled this with 'twisting the lobes around on the cam so the valves also open and shut at the new 120' firing sequence.

Hence if you put an oddfire dizzy in an even fire engine ( or vice versa )the spark will be in the wrong place at the wrong time.

I've taken this from the link I put above :-

"Put together all this information about the odd-fire distributor cap and you can see why, unlike an even fire engine, you can't just turn the distributor to the next ignition point, move the wires around to match and still have a running engine. If you need to rotate the distributor housing you can, but you need to do it by two wires in order to satisfy the even/odd requirements of the cap and distributor. If you've lined up your #1 plug to an even distributor contact instead of an odd contact the engine will still run, but not smoothly. This system works well as long as it is installed correctly, so good luck! "

Back to basics , has this engine ever run well ? ie are you trying to get it running AGAIN, or just getting it running ? Does the distributor look like it belongs with this engine?
 

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I've just had a thought ...you could work out if it's an even or oddfire by using a degree wheel on the crank pulley . Set it up on number 1 tdc then rotate the engine until number 6 comes to tdc ( next in firing order ) and look at the number of degrees it's travelled. If it's not 90 then it's an oddfire :tup:
 

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Discussion Starter · #9 ·
We havnt had the engine running properly yet because the carb
was leaking into the engine and ignighting the carb, but thats fixed now and will probably have another go at it on saturday.
In answer to info i downloaded on oddfire timing, go to google
and put in (buick v6 oddfire timing) and down the first page
it is titled (understanding the oddfire v6) about 5 pages,
merls garage, will update after saturday, tiddytime.
 

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Yup, that's the link I posted up earlier as well, shows the firing order as 165432 for oddfire , same as evenfire .It was the other firing order you quoted I was talking about "BUT SHOULD BE 145632 EVEN "?

Here's the evenfire firing order as yu can see, both the same :-

http://www.edelbrock.com/automotive_new/misc/tech_center/install/5000/5486.pdf

So moving the leads to improve the running can only have to do with pairing them up as I also posted above.:D

If you do the tdc checks then you'll know which engine you have and the dizzy can be checked as being the correct one for that engine. A logical back to basics approach will win every time :tup:
 

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Discussion Starter · #11 ·
the other firing order was on one of the other google pages, it all depends
on how you word it, but if i get time over the weekend i will find it again,
i think i put in, firing order for buick v6 odd and evenfire engines.
TIDDYBOY.
 
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