1969 Z28 30-30 Camshaft? - Team Camaro Tech
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post #1 of 7 (permalink) Old Jul 15th, 12, 12:34 AM Thread Starter
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1969 Z28 30-30 Camshaft?

'69 Z28 car. I want to know if I have the Z28 cam or not.

I have no history on the engine, only what I can see from codes and visual inspection. The camshaft is definately mechanical (I adjusted the noisy lifters). At 950rpm idle it is pulling 15-17 inches of mercury. Would that rule out it being the 30-30 camshaft?

The engine runs strong and has been detailed as a Z28 (4053 carb, Winters inlet, cast manifolds with smog pump) so would seem strange they would not use one as so much else is correct.

Other info-
From a clutch change the crank has the pie crust cut out so I assume it is a 302. The block is 3970010 (but that could go either way and cannot trust the block DZ stamp). Heads are 186 (date coded January 1970).

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post #2 of 7 (permalink) Old Jul 15th, 12, 04:31 AM
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Re: 1969 Z28 30-30 Camshaft?

Hey Eddie, welcome - and great choice of car! What part of W London are you in? I used to live in Hammersmith/Shepherd's Bush area, loved it! Now back to your question:
Short of pulling the cam, you'd need to be familiar with using dial gauges and a degree wheel to detemine approximate cam specs (lift, duration etc); Measuring lift with solid lifters will be more accurate than hydraulic lifters, but if cam lobes, pushrods etc are worn and unevenly so, you won't get accurate readings - but should be close enough to determine if you are in the right ballpark. Bear in mind also that even if the engine still has a Z/28 cam, it could be the 140 off-road version, so be prepared to check your findings against factory specs of this too.

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post #3 of 7 (permalink) Old Jul 15th, 12, 06:22 AM Thread Starter
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Re: 1969 Z28 30-30 Camshaft?

Further West- Egham, near Heathrow.
Many thanks for the response.

Degree wheel is going to be tricky with the engine in. I'll have a look and see if it could work in situ. I have wheel, dial gauge and stand and have done this before on engine rebuilds so it's just setting up.

but....any posts that I have found so far seem to put the idle vacuum at around 9-10 for these cams. Just wondering if I can rule out the 30-30 or 140 at this stage or if there is still hope!

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post #4 of 7 (permalink) Old Jul 15th, 12, 07:46 AM
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Re: 1969 Z28 30-30 Camshaft?

Or you can place masking tape on the circumference of the harmonic balancer and use the existing TDC and 10 scale marking the tape every 10, or get at timing tape for the correct diameter of the h/balancer and measure the degrees of valve action and compare to documented lists of camshafts for vlave opening/closing and valve lift.

I suspect, like you, there is a milder camshaft since 15-17 inches of vacuum.

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post #5 of 7 (permalink) Old Jul 15th, 12, 07:56 AM
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Re: 1969 Z28 30-30 Camshaft?

Maybe an LT1 cam...


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post #6 of 7 (permalink) Old Jul 15th, 12, 08:13 AM
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Re: 1969 Z28 30-30 Camshaft?

I think the 30-30 cam will only give you 6-9" of vacuum on a good day. That's why it requires the B25 vac advance can for the distributor.

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post #7 of 7 (permalink) Old Jul 15th, 12, 09:23 AM Thread Starter
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Re: 1969 Z28 30-30 Camshaft?

I'll probably leave it until it's time to pull the engine and then strip and id every part. If the reciprocating parts are 302 then I want the 30-30 or 140 back in it. I didn't buy this car for an easy life! Just installed the B28 distributor cannister so I'm prepared.

Thanks again
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