906 valve and port size

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08-26-2009, 01:42 PM
v-8

906 valve and port size

I am looking for confirmation of the 906/911R valve size(s) and port size(s). I have NOS 2.0L heads that need adjustment and I want to make sure I got the numbers right before having the work done.

Of course I have found some 'internet sources' but I'd appreciate a more 'definitive' answer/source - i can only have them re-worked once :)

Many thanks for you help
08-26-2009, 02:18 PM
Flunder

906

Hello V-8

From memory:

Valves: 45i and 39e (same as 69S)

Ports: 38i and 38e (really big for a 2L, lets the 906 cam do its job)

Some 906 heads had injector ports (901/21 for the 906E with mfi) but most did not (901/20 with tall manis and 46s).

But, do the ports 36i and 35e if you anticipate street use as you will have insufficient port velocity for any low end response with a 2L breathing through 906 sized ports.
08-26-2009, 07:33 PM
kenikh

Quote:

Originally Posted by Flunder

Hello V-8

From memory:

Valves: 45i and 39e (same as 69S)

Ports: 38i and 38e (really big for a 2L, lets the 906 cam do its job)

Some 906 heads had injector ports (901/21 for the 906E with mfi) but most did not (901/20 with tall manis and 46s).

But, do the ports 36i and 35e if you anticipate street use as you will have insufficient port velocity for any low end response with a 2L breathing through 906 sized ports.

Your memory is correct on the specs, but you CAN get 38mm ports with better intake velocity than the stock 36/35 ports. Modern CNC port jobs can brerathe big and create amazing velocity. My '69S heads went to Steve Weiner and got opened up to 39mm for a 2.3L motor. Look up "extreme hardcore head porn" in Search to see pics of my port job to see what I mean.
08-27-2009, 12:04 AM
chris_seven

906 Ports

D shaped ports seem to be recommended for early 2.0 litre engines and I would be interested in opinions about how worthwhile this would be.
08-27-2009, 04:22 AM
v-8

Thanks guys - so far my 'sources' are confirmed. I am thinking of using the 69S valves as they fit the job - any experience to share is welcome.

The engine (901/03) will be running with 46 Webers, 906 cams and 81.5mm PMO manifolds (RP's recommendation and furthermore, the 98mm does not fit with K&N's). Obvious potential concern is the low end response so that makes any suggestions on the 'port job' very welcome !