Currently have a '91 twin cam w/approx 109k miles on the motor. Motor overheated on previous owner. Head was yanked and resurfaced.

The car has a bit of an oil consumption issue. Under full throttle it burns a small bit of oil in the upper RPM range and sometimes a puff between shifts. I imagine this is a valve issue. Then again the car was run pretty hard with less than a quart of very old, thick oil...so I may have other issues going on in the bottom end.

Instead of going with an SR, I'm thinking about doing a little bit of cheap work to the KA and start autocrossing again. Curious what sorts of cam options I have out there. Also interested what sorts of gains, if any, the KA sees with minor head porting. Does anyone out there offer a ported head package?

Also, how much does an average complete head off a low mileage late model KA go for? Would I be better off just swapping the entire motor for a lower mileage/newer KA?

Appreciate the help.

 

I have a DPR ported KA cylinder head here at Enjuku. We're about to put it on a 650-700 hp KA.

As far as cylinder work goes, people usually put the OE S13 exhaust cams in both the intake and the exhaust side of the KA24DE. Sometimes that doesn't do enough gains for people.

There are then the following aftermarket camshafts

PDM - These are regrinds from the stock cams, from what customers have told me.
JWT - Jim Wolf Technology - Make great gains over S13 cams from what a few guys who have used them have said. Jeff240SX uses them on this board, a few others such as Orion use them on FA.
WEBB - Race Only, these guys make the same cams for the Dakar cars.
CROWER - Well known for dropping the ball on B-Series cylinder head products such as cams and retainers, crower has bounced back to produce a multitude of cam options for the KA and SR, Five different grinds in all, not to mention the ability to stagger the cams.

Valve Springs and Retainers

There are three main companies that do them
Ferrea
SuperTech
Crower

You can't go wrong with Ferrea, they've simply been in it too long with too much good luck with everyone I've ever spoken to regarding Ferrea, and a KA application rules.

Supertech is the chepaest as far as I know, I haven't heard anything one way or the other.

Crower's retainers and valve springs are very good for the SR20, So I would assume that the retainers for the KA are just as good. I haven't spoken to anyone who's run them just yet, however.

For the Fully Built DPR stage 4 cylinder head that we're putting on the 650hp KA, we went with Crower Stage 2 Turbo cams, Ferrea full valve train, and we're debating stainless steel valves available from Ferrea as well.

Hope this helps, and as always, you know I deal with all of this stuff -


By the way, the cylinder head that DPR did for our Uber-KA has the following

Completely Reshaped Combustion chambers
Unshrouded Valves
Clover leafed combustion chamber
CC'd and bored for .20 over (same as engine bore)
hand ported and flowbenched intake and exhaust ports
5 angle valve job ( but will be replaced when we install the stainless steel valves and berrylium valve guide set)

 

Mr Mandingo:
Yes, I try to stock 1 engine worth at all times. I prefer Ferrea over Supertech.