Budget Ford 302 Project (Part 4) Baseline Cam Duration Measurement

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26 күн бұрын

Update:
It was brought to my attention by a viewer that camshaft manufacturers give their timing events in terms of tappet lift where I did the measurements in terms of valve lift.
I think they do that because things like rocker arm ratio and valve train geometry will effect the angle reading at a given valve lift and because that is so often different from engine to engine it is better to specify in terms of tappet lift. When tappet lift specs are used it makes it easier to compare one camshaft to another.
The way I measured the events at the valve can be used to compare the two camshafts that I have for this engine but the values would not correlate well to a cam catalogue.
In this video we measure the baseline cam intake and exhaust duration along with valve lift and overlap to better understand the current performance figures.
This information will also put into perspective the dimensions of the cam that is going in next.

Пікірлер: 12

@dougzack4565 24 күн бұрын

Great video. I’m looking forward to the next one.

@engine_therapy 24 күн бұрын

Thanks

@edsmachine93 20 күн бұрын

Thanks for sharing. 👍 I just subscribed to your channel. Good luck with your build.👍👍

@engine_therapy 20 күн бұрын

I appreciate it.

@jeffdiehl8394 24 күн бұрын

great visual! thank you for doing this. That cam spec is why it makes 22+ inches of vacuum at idle and the Speed density EFI worked well. also why it's out of breath at 4500 or less! 9 degree split, low overlap - good truck and large barge passenger car cam probably designed in the 70's. not sure how much lift those springs & retainers can handle, probably .450-ish? 205 @.050intake/212exh will wake that engine up! looking forward to it. Jeff

@engine_therapy 24 күн бұрын

I think I will take some time to look into the springs and retainers.

@brentonk461ismylostaccount 21 күн бұрын

Degreeing the cam, cam timing is done with the rockers removed and two solid lifters. You can still do it with the heads on by using the pushrods and dial indicator. You then check rocker ratio by checking lift at the valve with the lite springs.

@engine_therapy 21 күн бұрын

Solid lifters would eliminate the bleed down completely. I kept an eye on the bleed down on the indicator and there was very little, maybe .001" at most.

@craig8187 19 күн бұрын

The common indicated figures in the catalogues are. 006" tappet rise for advertised on a hydraulic cam(.020" for a solid cam) and .050" tappet rise for your degreeing figures. Not taken at the valve. Yes of course figures can be taken at the valve as this is what the engine actually sees but at the valve figures cant be compared to most catalogues. Absolutely ok to check at the valve if just comparing different cams in the same engine and not trying to correlate the info you gather with a catalogue.

@engine_therapy 19 күн бұрын

Hello, Thank you for the feedback. I did some looking around and it looks like you are correct. I guess I was always more interested in what the valve was doing. Measuring at the tappet is the way to compare to catalogue numbers. I should mention it in the description and say something about it in (part 5).