Cam Question: Square tooth vs. Round Tooth

[85GLHT-Omni]

A couple of cam questions...not to the typical ones, though...

87 and earlier cars got slider cams with square tooth sprockets?

88 cars got roller cams with square tooth sprockets?

89 and later cars got roller cams with round tooth sprockets?

What year did standard Omni's get TBI?

[turbovanman²]

87 and earlier cars got slider cams with square tooth sprockets? YES

88 cars got roller cams with square tooth sprockets?YES EXCEPT 2.5L GOT ROUND TOOTH

89 and later cars got roller cams with round tooth sprockets?YES

What year did standard Omni's get TBI?NOT SURE

[BigAl]

I think standard Omni's got TBI in '88....Im not positive though

[GLHSKEN]

Omni's NEVER came with the 2.5L....

[BigAl]

yep, this is from allpar

"In 1988, fuel injection on all Omnis and Horizons is standard. This engine developed 93 bhp. 1989 brings some changes to the engine which allow for quieter and smoother running. Major service pointers are highlighted with paint for checking fluid levels."

[GLHNSLHT2]

who said they did???:confused:

[85GLHT-Omni]

Thanks for the help.

So an 88 cam is best option from an 85 slider? In that, the 88 cam does not require an advance in cam timing. I'm currently running an 90 turbo I roller cam on a G-head, advanced 4 degrees and I'm satisfied.

For a given year, say 1990, is there a difference between the 2.5 TI cam and the 2.2 TII cam? or 2.2 TI cam (if there is such a thing)? Getting a cam is also a matter of blind trust, as there are no markings on cam?

I've read the debates and I'm not sure anyone cam is perfect. I definitely want to go with a roller cam, and getting an 88 seems like it saves on needing to get a adjustable cam sprocket. I also need a setup that will not be too lumpy and will pass emmissions.

[turbovanman²]

There is no way to tell what cam you have without having a shop with a cam doctor check it out. They say the 88 tbi 2.2 cam is the best below 20 psi.

[R/T]

What he said, as old as our cars are, you can never tell what cam it is...

Too many rebuilds.

[CletusJones]

what's better, square tooth or round tooth? My car currently has the square tooth variety and I was wondering if I should keep it like that when I swap a turbo motor in.

[turbovanman²]

what's better, square tooth or round tooth? My car currently has the square tooth variety and I was wondering if I should keep it like that when I swap a turbo motor in.

You have to keep what the engine came with, its not interchangeable.

[CletusJones]

You have to keep what the engine came with, its not interchangeable.
why? you can't just change the sprockets?

[turbovanman²]

why? you can't just change the sprockets?

Cam and aux shaft yes, crank no, there is no CB block square tooth and vice versa, no round tooth reg block.

[GLHSKEN]

who said they did???:confused:

LOL I was referring to Simons, 88 answer. Omni's got TBI in 87... IIRC. There were no more carbs after 86

[turbovanman²]

LOL I was referring to Simons, 88 answer. Omni's got TBI in 87... IIRC. There were no more carbs after 86

Lol also, but I never mentioned Omni in my answer, :p

[GLHSKEN]

Maybe I was pulling a Russ!@!! ;)

[CletusJones]

Cam and aux shaft yes, crank no, there is no CB block square tooth and vice versa, no round tooth reg block.
Ahh, that's the missing piece! I didn't know it was cast into the crank

[turbovanman²]

Ahh, that's the missing piece! I didn't know it was cast into the crank


Its not, it comes off but the cranks are different on early and 89 and up. Although, the 2.5 tall deck has a round tooth but nevermind, stick with the belt the engine comes with.

[bobr19]

Although, the 2.5 tall deck has a round tooth
Theres the answer for non CB round tooth if you want to go that way bobr19

[iTurbo]

L-bodies didn't come with TBI fuel injection till '88. Up through '87, all n/a L-bodies were carbureated.

[Dave_J]

My 87 OMNI had the vacuume secondary carb. Square tooth belts are a little less prone to skip and round tooth belts are a bit quiter. DaveJ

[PentastarTurbo]

L-bodies didn't come with TBI fuel injection till '88. Up through '87, all n/a L-bodies were carbureated.

yup..

I have a 85 turbo z engine for my build up.. I wanted to go with a roller cam and had to wait for a 88 turbo shadow to pop up.. That way everythings square tooth and I have a nice clean idol.. I didnt want to invest into a 88 tbi cam because i hate keyways because i always used to sheer those off even being carefully.. That and i didnt want to spend any money on a square tooth adjuastable cam gear when i know ill be going common block once I get the bugs worked out with the 85 engine and 88 electronics on a T2 induction setup :)

so for all you square tooth guys, 88 is the year if ya want a roller cam.. :)

[85GLHT-Omni]

88 TBI cam needs no cam timing advance, correct?....G-head, 88TBI Cam, Square tooth sprocket. After 88, you need 4 degree advance when using a roller cam on a square tooth sprocket? This needs to be a FAQ.

Are 85-88 cam sprockets identical? Since I already bought a square tooth adjustable cam sprocket, what gains can be had by advancing/retarding the cam timing?

[PentastarTurbo]

88 TBI cam needs no cam timing advance, correct?....G-head, 88TBI Cam, Square tooth sprocket. After 88, you need 4 degree advance when using a roller cam on a square tooth sprocket? This needs to be a FAQ.

Are 85-88 cam sprockets identical? Since I already bought a square tooth adjustable cam sprocket, what gains can be had by advancing/retarding the cam timing?

I thought in general ya needed to retard the timing on a tbi cam when used on a turbo car? 4 degrees? Thats what I had to do to push the pull into the right rpm range.. it would either take forever to get goin or prematurely haull arse for the first couple of 10=1000rpms ;)

then again I was runnin a routh tooth relentless gear on a cb build up

[turbovanman²]

88 TBI cam on a square tooth setup needs no advancing. Gary's adjustable sprockets-some where out a few degrees.

[briceturbosports]

L-bodies didn't come with TBI fuel injection till '88. Up through '87, all n/a L-bodies were carbureated.

sorry but 87 was the cross over year some 87 omnis had efi most had carbs but there were a few out there when i was at the dealer :)