Ka exhaust camshaft broke

General discussion forum about the 240sx, and a great place to introduce yourself to the board!
07Bear
Posts: 1
Joined: Tue Oct 13, 2020 3:34 am
Car: 1991 Nissan 240SX SE
Factory original "KA24DE/5-Speed"

Post

Dad’s 240 ka motor broke the exhaust camshaft at the sprocket.
Probable valve damage.
He has has others work on it for him and a lot looked shady/ shoddy.
I have the car in hand, to assess and repair.
I am a domestic pushrod guy, so here I am asking for help or advice.
Looks like the guide broke off and jammed into the exhaust sprocket and broke the end off the camshaft.

What am I looking at as far as repair?
I would like to do a Sr20det swap, but I want to retain
The appearance of the old Ka setup.
Does this require dash/gauge swap.

A little history of the car:
It was bought by Dad for Mom new in 91’
All original, he gets stopped all the time by 240 enthusiasts/purist.
It has sentimental value.
He it 78 and loves the car.
Me a son and a domestic guy, who wants to make it right and maybe bump the hp with a stock SR/turbo,
but does not want to butcher the car.
Engine swaps are not a big thing, but time is of the essence.

Any advice would be appreciated.


User avatar
NukeKS14
Posts: 310
Joined: Wed Apr 10, 2019 2:50 pm
Car: 1995 240SX SE - KA24DE-T
AC Cobra Mk IV Rep.
2020 Civic Si

Post

SR swap would not require modification to the dash/gauge cluster. You can swap it in and the only major thing that'd need to be done would be the wiring harness and fuel pump to support. redtop SRs are pretty cheap at the moment. Especially if you're just looking to get it on the road and not hop it up. You'd need an engine/harness/ecu/trans though. then you'd have to come up with something for intercooler piping (not a big deal, lots of options but more parts = more $.)

Another option is to install a different head and do a mild refresh while you're in there.

That'd be the cheaper option of the two. Yeah those timing chain guides are nothing but trouble. There are 2 on the upper chain that Nissan recommends removing for this reason and the noise they cause. Sometimes they break off and clog the oil pickup too. Glad he's still enjoying it after all these years. As far as the heads go, you want to look for one from a 240sx. The KA engine was put in Altimas and some of the nissan Frontiers but the heads are different on the FWD Altimas and I'm not 100% on using a truck head on the engine. If you have a boroscope, check the piston tops for damage. If they are, that may factor in to your decision before you even bother tearing the current engine down as well.

here's a well documented SR swap guide with pics so you can at least look at what you'd be getting in to;

http://speed.academy/nissan-240sx-sr20d ... de-part-1/

I'm not sure how comfortable you are doing wiring but there are a few write-ups on doing a conversion on the SR harness to swap over into the 240s but you're also gamb|ing with a 20+ year old harness that's been janked around during removal/shipping etc... in my opinion, it's better to get a premade one for your application. It'll make the swap truly bolt-in and all of the gauges will work correctly, plus it's new wiring. Wiring specialties is about the only game in town I'm aware of. I'll leave my personal opinions out of it but they warranty their harnesses, I believe. Factor that in to your cost as well if you land on swapping.

Another consideration would be CA18DET. it'd still give you a small bump in power over the KA. I'd at least do a price comparison for posterity. Best of luck. Lots of options for the car without mutilating the frame/chassis.

User avatar
PapaSmurf2k3
Site Admin
Posts: 23998
Joined: Thu Nov 21, 2002 3:20 pm
Car: 2017 Corvette, 2018 Focus ST, 1993 240sx truck KA Turbo.
Location: Merrimack, NH

Post

NukeKS14 wrote:
Sun Oct 18, 2020 7:44 pm
If you have a boroscope, check the piston tops for damage.

Another consideration would be CA18DET. it'd still give you a small bump in power over the KA. I'd at least do a price comparison for posterity. Best of luck. Lots of options for the car without mutilating the frame/chassis.
My thoughts exactly. Check out the pistons first and go from there.
I'm not typically an advocate for the CA18... especially for a domestic pushrod guy haha. You really have to rev the piss out of them to make power. There's no one home under 3000 rpm :rotfl

Basic breakdown of engines:
KA24 - 2.4 liters, longer stroke, higher low end torque, lower redline. Plenty of turbo options and aftermarket support. Cheap.
SR20 - 2.0 liters. Less torque than the KA. Built for turbo from the factory. Higher redline. Still strong aftermarket support.
CA18 - 1.8 liters. Even less low end torque. Also built for turbo from the factory. Pretty darn high redline. Less aftermarket support than the SR.

I also agree if you're pulling the engine, you should replace the wiring harness while you're in there no matter which engine you go with.


Return to “240sx General Discussion”