Single sidedraft with stock cam ?

Webers, Cam selection and Ignition upgrades.

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lvsanchete72
Posts: 34
Joined: Fri Feb 20, 2015 2:39 am
Location: San Diego, CA

Single sidedraft with stock cam ?

Post by lvsanchete72 »

Anyone out there ?
Anyways wondering if anyone knew how much performance boost can be pulled from a single side draft without changing the stock camshaft.
Since I'm from California I want to keep in the cam and just every year swap a few bolt ons, such as headers and well possibly a better carburetor. (Also would I need upgrades from the mechanical pump ?)
I was also thinking of getting a new head with bigger ports but I also know a good cam would improve performance greatly.
On that note if someone knew of a camshaft that could pass smog in california but was better than stock that would be cool too.

I mean with two cams wouldn't I need to have different bearings for things to fit or swapping cams every two years is possible ? Or even doable with the engine in the car ?

Thanks for any advice !
Rodger
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Joined: Fri Jul 19, 2013 1:24 am
Location: Australia
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Re: Single sidedraft with stock cam ?

Post by Rodger »

Hi.

Bolting on a single side draft of 40mm PHH design will not give you any more performance per sae. It will allow more air flow up in the higher revs to produce power up there. However the standard cam works in balance with the stock carburettor. The cam runs out of performance, the valve train begins to bounce and the carb runs out of air flow all at the same time.
With a change to a better flow capacity of the Solex you will be limited by the cam and valve bounce.
Adding a good header will improve efficiency and may produce better mid range but I would be hard pushed to feel any differences.

A Side draft carb does produce a good sound!

Put on a single side draft so it is there when you want to change the cam. It can be jetted to suit. Whether it can be made to pass smog tests well? Toyota did build the motor combination to pass the test back in the day and I believe a carb modification in CA is considered for "Racing purposes only" so violates any smog laws straight away.

Changing 2T/3T cams can be done without taking off the head but you do need to loosen off the sump to remove the front timing cover. Taking off the timing cover means dropping the coolant, taking off the pulley and fan assembly (perhaps the radiator for clearance). Then new gaskets to go back on to seal it up again. Normally you need not do anything with cam bearings, simply slide in and out the cam. The cam followers can be held up out of the way to allow the cam to slide in and out. The valve clearances will need to be set every time you change cams.
To do this twice a year would be tedious and impractical.

Or build that head up you mention, with the side draft ready to swap over as a whole unit and all those cam related things above can be done together.

A bit easier on a 2T-G as the cams can be pulled directly out from the top of the head. No coolant and no pulleys or gaskets to remove and replace. There is room to remove the cam gears. The bugger is setting valve clearances each time you change cams. You need a good rage of shims and patience.

Regards
Regards
Rodger
Lover of the Solex/Mikuni sound
http://www.rmcarburetors.net
lvsanchete72
Posts: 34
Joined: Fri Feb 20, 2015 2:39 am
Location: San Diego, CA

Re: Single sidedraft with stock cam ?

Post by lvsanchete72 »

Thanks for the info Rodgers, if say I was to get my hands on a spare 3tc head what would be the appropriate work to be done on it to maximize the potential of a single side draft given that I would most likely not be upgrading the fueling system, but might be changing the camshaft ?

In California a smog test is required every two years and perhaps if I have a spare head with the side draft it might be a weekends worth of work to change from one set to the other.

The concern of valve clearance would also be removed correct? I could have each head be optimized for the stock carb and cam and the second for the side draft and a performance cam.

If I were to go with this second set of bolt-ons, the head, side draft, headers and cam, what would be the best cam to fit given the possible limit of mechanical fuel pump ? I think having an electrical fuel pump might be too evasive to be switching every two years, but I might be wrong. Could a fuel pump also be set up to be modular enough to be swapped with the other things ?

And given that the internals of the block are all stock what would be a cam that could improve and not be too damaging to the stock internals? So what cam would you recommend for a semi daily/ occasional track day + canyon runs single side draft set up? And what upgrades should be done to the head ? Maybe a port and bigger valves ? and perhaps upgraded push rods ? Thanks in advance !
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Spudenater
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Joined: Tue Jun 25, 2013 5:53 am
Location: San Antonio, TX

Re: Single sidedraft with stock cam ?

Post by Spudenater »

I am running a single Weber 40 DCOE with my stock cam, and it has made a great improvement over the stock carb. I'm also running the mechanical fuel pump. Over 40k miles with this setup as a daily driver, and I couldn't be happier. I also have a ported and shaved pre-EGR 2TC head, 4-1 headers w/ 2.5" crush bent pipe all the way back, and a lightweight flywheel. I'm also going to cam it soon and get my distributor re-curved, but as it sits my wagon is barrels of fun!
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