Oddfire camshaft

[gdouaire]

Got this Isky 1171-TA "TurboCycle A" camshaft. A very mild turbo camshaft.



In the meantime, i'm finding out my own odd fire V-6 is one of the few to have a non-"take-apart" camshaft with the odd-fire grind. This means, the camshaft has the integral gear and all, but the odd-fire pattern. So, because of this, I'm not sure how the various pieces (such as the pump eccentric, dist drive gear, etc) will fit together.



So...Any schematics somewhere? I don't understand how the recessed key on the camshaft will fit with other items I see online being flagged as "odd fire". And my Buick 1977 shop manual is still in the mail...

 

[750H.P.V6]

What you're saying is very interesting as I have never seen an Oddfire cam that has an integral distributor drive gear and takes an Evenfire timing set. What is the back story on this engine?

Neal

 

[gdouaire]

I was confused at first, when I looked at that camshaft. However, this is a documented setup - found this in Pat Ganahl's V6 performance:

"Although Buick switched to the even-fire configuration during 1977, the cam change came a few months earlier. The majority of integral-gear cams are even-fire, but some were made in the odd-fire pattern..."

That book is really really useful.

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[gdouaire]

From this image (v6 performance) -- camshaft has a recessed keyway,gears also have a recessed keyway. Some form of "tab" to insert in the keyways not shown on picture below (odd fire depicted on the right)?

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[750H.P.V6]

The cam you have pictured on the right is typical of an Oddfire cam. The cam takes a woodruff key like the one that goes in the snout of the crankshaft. The camshaft gear, fuel pump eccentric and distributor drive gear slide onto the nose of the cam and the components are held in place by a large bolt that threads into the end of the cam. Just as a question; The motor does have a common pin crankshaft correct?

Neal

 

[gdouaire]

Not there yet - not able to see the crank right now in the engine teardown. It had an oddfire distributor, and came from a 1977 Pontiac Sunbird... will find out soon about that crank.

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[gdouaire]

The cam you have pictured on the right is typical of an Oddfire cam. The cam takes a woodruff key like the one that goes in the snout of the crankshaft. The camshaft gear, fuel pump eccentric and distributor drive gear slide onto the nose of the cam and the components are held in place by a large bolt that threads into the end of the cam. Just as a question; The motor does have a common pin crankshaft correct?

Neal

Finally got to see the crankshaft - and it does have common pin crankshaft, which makes it an oddfire.

And this is the camshaft, which is the "new", one-piece item.

 

[Jay J]

Maybe the manual you are waiting for will tell the tale. Perhaps a new front cover wold work in this--Maybe Earl knows!

 

[750H.P.V6]

Yep, It's definitely an Odd fire motor. If you still need parts for the nose of the cam you can get them from TA performance or DLS, they should have the timing sets, gears, spacers etc. in stock.

Neal

 

[gdouaire]

I am just wondering... I already have a timing set for an oddfire engine, and both the camshaft and the pulley have recessed keyways. See images below. I have bought 1977/1976 Buick manuals, they do not show enough details. I'm thinking the recessed keyway on the Isky camshaft is not compatible with OEM components. Thoughts?

Unless there's a metal pin that is used to "lock" the two keyways together? Never seen this before.

 

[ek02]

It's been about 20 years since I had an odd fire, but I am pretty sure that the crankshaft key and the camshaft key are the same. You may want to call TA Performance for some advice. They stock the keys and all the parts you may need for the nose of the cam. The front cover on an odd fire has different timing marks than an even fire, so you will need to use an odd fire front cover and dampner. You will also need some way to limit camshaft end play. I used to use a hardened stud with a rounded end screwed in to the cam, and then a nut and a washer that goes on the stud to hold the fuel pump eccentric and gear on. Adjust the stud so it has .006-.010 against the front cover. There was also a thin washer that you would bend over the nut to be sure it stayed tight. Lock-Tite on the nut worked for me. Some people screw a plate to the cover for the stud to hit against. I never did. You could also use the factory bolt to hold it all on, and a spring loaded bumper that goes over the bolt on the front of the cam and pushes on the cover. I have had the spring break, though. I would also use a double roller chain and gears. The timing gears take a beating on an odd fire. Those odd fires sounded pretty good, but they will shake you to death at idle.

 

[turbodave231]

The timing sprocket you pictured will work on the Isky cam. The even-fire billet roller cams have the same nose configuration and use that style timing sprocket. You can order the cam bolt that has the needle thrust bearing (rides on the inside of the timing cover). Set end play to .005-.007 and you should be safe.

A crank key works perfectly in the camshaft keyway.

 

[ek02]

TAROL150D is the adjustable roller cam button. Looks like the best and easiest way to go like turbodave231 suggested.

 

[gdouaire]

I am always surprised at all the knoweldge there is on this forum....! many thanks to all contributors I see much clearly now.

The next step on this engine will be head porting.

 

[gdouaire]

There! Parts secured.