Porting SJ 413 Heads - G13A 8valve

[Kalahari]

[b][/b]Hi, My wife ran my SJ 413 so hard on the highway itblew a head gasket between 2-3 cylinders and has been stripped for decking and skimming.
Before I put it together I would like to know if anyone has any experience with improving air flow on the 1300cc 8 valve heads. My 1986 engine has the air pump supplied air tubes in the ports. Not sure if they all have this feature but it seems to be a bit intrusive even though it is on the short side radius of the port. In addition the port has some swells to initiate swirl and air/fuel mixing. They seem to deflect airflow into the valve head instead of allowing smooth flow around

1) What is the result of removing these bumps? the valve head.

I have a Superflow 110 flow bench and want to run a before and after porting test but cannot find the factory cams valve lift specs in anywhere.

2) Does anybody know what the stock specs are for intake and exhaust and any cam specs such as duration, intake center line, overlap, IVO, IVC, EVO, EVC etc?

3) I have searched the net for some good tech info on these heads but have found nothing. Is there any thing out there that is of value?

4) What range of aftermarket cams are available and from whom?

5) Does anybody have any experience with these aftermarket cams in the SJ 413.
I want to retain as much offroad capability that I can, but the engine is all in at 4500rpm which is a real handicap on the open road here in South Africa. (We have big spaces.)

6) Lastly, does anybody know if David Vizard ever did any development work on these heads and if the results have been published anywhere?


Thanks

:suzuki:

[ScottieJ]

Here is a thread on pirate 4x4 it's probably the most detailed info you will find anywhere on the internet! Shame your in South Africa as I want some work done on the head on mine.
http://www.pirate4x4.com/forum/suzuki/6 ... heads.html

There are aftermarket cams available in the US have a look on this website http://www.sammypro.com

Valve sizes on various suzuki engines can be found here http://www.suzukiclubuk.co.uk/tech-spec ... gine-specs

From what I have read there is more lift on the 1298cc cams than the 1324cc but don't have the actual specs. I think the rockers on the 1324cc carbed engines have a 1.5:1 ratio and the 1298 spi has 1.3:1 ratio. it's from the pirate thread

Something else I can add to this that hasn't come up......the rocker arms in my 1992 1.3 were lower ratio...1.3-1 than the carbed 1.3's.....1.5-1. They made up for it with the cam grind.

The best combo I could come up with at that time was the stock EFI cam with the 1.5 ratio carbed rocker arms. Installed the 1.6 exhaust valves, flat tops from the 1298cc in my 1324cc, and added the adjustable sprocket to fine tune things and it ran like a champ. The Isky actually made less power. One of my junk 1.3's had some huge rods that were twice the size of the ones from either of my other parts motors, so I used those too.

Got a speeding ticket to prove it! 89mph and still accelerating on 32" TSL Radials. Broke motor mounts like crazy, even the Dodge v-8 mounts only lasted 6 months.

Sorry that's about as much info as I have I think.

[ScottieJ]

Kalahari emailed me some updated info on his porting and flow bench results as he was having trouble posting the information up, here it is.

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"November was some time back and I still do not have the anus on the road yet. I did however get a chance to flow the head in stock condition in January and will post the results here.
It was a mission as my head adapter has the smallest bore insert at 83,4mm daim. Getting one made at 74mm diam. is not an option right now. This will flatter the absolute flow figures but as long as the condition is the same for a “before and after” it will show us something.

The heads were sent for new guides in December and so seats were re-cut and the valves finished with a 45* back cut.

I ported the heads last week and spent less than 15 minutes per port. I was done with all 8 in less than 2 hours, so it was not an ultimate effort by any means.
On the Intake, I broke the EGR feed pipes off with a long nosed plier (be careful not to damage the seats) and then ground the remaining stub back to the port wall. See pics if I can eventually get them posted. I then removed the swirl deflectors in the port on the long side radius and blended the short side radius which is terrible in stock form with an overhang of note. This causes the air to separate from the port floor and tumble. (intended to aid in mixing of the fuel, keeping it in suspension) Be careful here as too much material removal is not a good thing. The deflectors must have been designed-in to assist air/fuel mixing to meet USA and Eu emission legislation but deflect the air into the back of the valve and do nothing for flow.
On the exhaust I removed the deflector on the long side radius which I cannot understand the purpose of. It cannot affect mixing and is a direct impediment to gas extraction and scavenging of the chamber.

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Some nice improvement in flow resulted in lift above 3mm in both intake and exhaust. To improve low lift flow a lot more work has to be done on the seats and valves. The valve spends 30 to 40% of the opening and closing event in the <3mm lift zone per event and so offers scope for a lot of air flow. The seats on this head as is, are really not beneficial to high flow with the contact on the extreme inside edge of the seat. They will last forever but as you can see from the data low lift flow remains essentially unimproved.
Maybe next time I will venture into this territory but I need to get it running now. Low lift flow improvement adds to flow throughout the valve movement but is far more noticeable just off the seat to 3mm.

Note that the data is at 10” Water differential and uncorrected for STP or sea level conditions. The pressures and temps are given in the tables, so can be calculated if you need to. My Superflow 110 sits at 1250m altitude and that’s where I do most of my driving as well.

I tested Cyl #3 in standard factory condition and re-tested it again after porting.
To check consistency I also tested Cyl # 1 intake and exhaust and they are fairly consistent over the valve movement except for the Intake low lift as per above comments.
From the % Change, the exhaust looks like it shows a higher % improvement as it is an easier port to work on. There is a casting protrusion for the guide which can be reduced (if you have a head to cut up and can see how much material there is) and it should show significant gains when opened up"

He also sent me a few pictures of his SJ gotta say it looks really tidy!

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[Rhinoman]

Did you try flow testing it with the intake manifold bolted up, there was a guy in the US that used to rework the intake manifold and that was supposed to give good gains when used with a Weber. I have been collecting some cam specs here:
http://rhinopower.activeboard.com/t5359 ... aft-specs/

[Kalahari]

Sorry Rhinoman, I could have gone to town at the bench but I am just too busy. I flow the V8 stuff like that with intake and carb attached but then it is an all out power motor that has cost ZAR 90k or so and is worth noting the numbers. Thanks for the cam data. I searched everywhere for info on the stock cam and even wanted to degree mine with the dial gauge but just ran out of time. I did test flow to 9mm which looked like max lift anyway and the port was stagnating around there.

[Rhinoman]

Sorry Rhinoman, I could have gone to town at the bench but I am just too busy.

That's always my problem too. Thank you for the information its always good to get real data on these things.