TheSamba.com :: View topic

Tue Dec 02, 2014 12:41 am

Ok I'll start off with the fact that these are 40hp square boss heads.(PLEASE don't tell me to post in vintage speed.) This isn't a cookie cutter vintage speed build and when I ask question there I'm given the same old formula. I want to do something a little different. I do want this engine to look like a 40 horse when completed.
Here is what I have planned and mocked up so far.
40hp case with cam bearings, case savers and full flowed.
74mm c/w 1600 style crank
Narrowed 40hp rods
1600 rockers
I have a Vangaurd dual carb kit
I've mocked up the short block using stock 77mm P/C and I looks like a set of aircooled.nets 85.5mm stroker P/C will get the deck very close to stock. I'll have to have the case and heads cut, run the rods without the bushings, have the barrels cut down to get deck height set and clearance the skirts but that will get me to 1699cc. I haven't decided on a cam yet. I'm hoping for a little input there.

Ok now lets get to the heads. I plan on having 1600 size valves and seats put in as well as new guides after I'm done. I started with a good usable head, no biggie if I mess it up I have a few good sets. It's hard to take good picture of the ports so bear with me.
First picture is the head before any work was done. The screwdriver is pointed at the step or sharp 90° bend that I blended out in the second picture.

This is after blending the step almost completely out. I didn't intent to take it down that far to begin with. Will removing that much hurt air speed considering the cc of the engine and the fact that larger valves will be added?

I did do some porting throughout the whole port but I just enlarged it keeping the same shape other than the area right under the valve seat and the odd lumps and casting crap.

Next question. How much of the guide support can be removed? I see it completely smooth in dual port heads. On the intake side it doesn't seam like it supports the guide much. Does it create some sort of venturi effect or help direct the flow around the guide better or does it just simply support the guide?

The exhaust side looks to me like it's about 50% of the guide support. So I don't think I want to take too much of that away. Is there any way to make this side flow better without making the head weak in the exhaust port?

I'm not building an all out race engine. It's going in a 63 beetle and most likely will be run on the stock 4.37 gears. It will not be run hard. I just want a really peppy little engine that looks like a vintage 40 horse. I know most will say I'm wasting my time but it's what I'm going to do. I'm open to any suggestions.

Tue Dec 02, 2014 2:36 am

There is no magic in the stock port shape, so preserving the basic shape does little good. I have never ported a set of those heads, but it seems like something has to be done about the guide supports. You can thin the exhaust support a fair bit on each side of the guide, and likewise on the intake. In general, try to straighten the port without making it too big.
It should have a slightly conical cross section towards the smallest diameter just under the valveseat. Remember that the valve itself is part of that area.
The division between the two intake tracts should be well rounded - think bellmouth radius.
I think you can go as far as FK8 with 1, 1 rockers, but that will surely be lumpy at idle.
There are tons of cams that I havent used, and you will surely get other opinions as well.

Tue Dec 02, 2014 4:21 am

You didn't say what carb set up is going to be used. You have the right idea on porting. Smooth and straighten the intake side as best as possible. Narrow the support area around the guide but don't remove it. The exhaust can be helped by reshaping the area just under the seat. But don't over do it.
Remember it is a street engine. you must retain the port velosity to have a smooth, clean running engine.
I would not waiste the money going to larger valves. Porting and changing the cam should get enough of an increase. Plus I think the ports can't be increased enough to take advantage of larger valves.
I would suggest an FK-65 cam. It can be used with the 1.1 rockers. It will give the extra duration needed without much added lift. You can always add more lift by changing to larger lift rockers if needed.

Tue Dec 02, 2014 10:26 am

first off I would clean the heads and check them out fully, change guides, change seats, I would use 40x35 valves. as far as porting.....I cant explain it well."D shaped.smooth raidi,do little to floor, dont under cut seats at short side raidi. profile guide bosses.....or better yet get duel ports, and get the duel port to singe port intake addaptor.

Tue Dec 02, 2014 3:15 pm

Thanks a lot guys. The carb set up i have is a vintage Vangaurd Formula Vee set up. It has a set of 28 pict carbs on the intakes now but I'm not sure if I'll stick with them or run some 30s. The intakes are kind of tall, I'm not sure how that will affect things.

Wed Dec 03, 2014 5:05 am

Nice vintage carb set up. With that tall of intakes you need to be careful not to go too large with the porting on the intake of the heads. The low RPM will get soggy. You should not have problems using them where you live. If I used them in PA., where I live, they would ice up fast in winter.

Wed Dec 03, 2014 10:42 am

If you are looking for how-to on heads performance, you will not find one. Speed people are not in very devulgatory mood when it comes to topend work.

Only way you can 'see' a fully done head is to buy them. That is the only time you can gawk at the port job all day long.

If you are referring to the Fisher Book 'old formula', it is still valid. Many things have happened since then, but that is a good point of reference for anyone who is looking for performance.

Power Secrets by S. Unich is also a good book to read. You will learn a lot from that.

The rest is from your experience. If you just want something to play w/, do what you want. But if you are trying to break a world record, then I suggest you do your own footwork and try it out.

When you go off the reserve, you are on your own.

Wed Dec 03, 2014 11:43 am

Thanks bugguy. I like the look of the tall intakes but i don't know how they will perform on a street application. There aren't many choices when it comes to 40hp dual carbs. I'm trying not to open them up too much. I'm mainly taking down the lumps and trying to make both port the same.

Nsracing. I understand that I'm not going to really get any pointers on what to do. I know good head porters have a lot of research and time invested in the their craft so their not going to give that information away. I'm not trying to break any records or use the engine for any type of competition.
I guess Im hoping that if i do something wrong or really f them up someone that knows will say something. If i could find a set of 40 hp heads professionally ported at the right price I'd buy them. The only guys that mess with 40hp stuff are formula Vee guys and $1500-2500 for a set is a little high for me for a street engine.

Wed Dec 03, 2014 1:22 pm

FVee heads are untouched. Cannot modify them at all. They only allow valve seat grind -that is about it. That is what makes it hard to have any advantage over another competitor.

Parts have to meet minimum. Intakes are chemically ported as they are not allowed to do any grinding at all.

For those guys, they hope to find a nicely casted set of heads.

Wed Dec 03, 2014 2:23 pm

I checked a few FV sites for parts and seen a few listings for ported heads. I assumed they were 40 hp head. Maybe something for a different class.

Wed Dec 03, 2014 2:32 pm

Here is what I've done to the exhaust side.

Wed Dec 03, 2014 4:47 pm

Hi here's my two cents I just got almost done building a 40 hp motor for my bobsy formula vee .i ported a set of 1965 40 hp heads ..I was going to install 40 x 35 valves in the heads but after looking at the small intake port where the manifold bolts to .i thought it would not help the flow if you can't get the air and fuel into the motor . So I cut the seats for 34 mm SS intake valves and 31 mm SS ex. Valves .i then ported the heads to match the bigger cut valve seats .then I cut the seats with a 3 angle valve job . I then removes all the valve guides and took out the guide boss on the intake port side .on the ex. Port I left the guide boss in place . Find a book called how to hot rod vw motors it has a good starting point on porting single port heads . I cut the heads for dual springs ..I to am using vanguard manifolds .i am using two EMPI carbs 30 pic with 24 ventures . In the old days all EMPI intake manifolds were tall .I think it was because the heads that had back then did not flow as much air as the heads we have now .so the tall manifolds really worked good .back then it was how much velocity you could build into your heads .in the old days dean lowery I think only ran 36 mm intake valves on his first race cars motors and used a stock crank and stock rods and 92 s cyls. It ran like a bear cranking it to over 8,000 RPMS . You can forget about using 40 hp rods on a 1600 crank or bigger crank the piston pin size is only 20 mm the 1600 and 92 mm pistons are 22 mm you might run them on metal to metal no brass bushing .if it was me I would run a better rod with the right pin hole like scat sells a 40 hp rod with a 22 mm pin hole with a bushing done the right way . There are 92 mm sets out there for 40 hp motors but the are $800.00 a set on samba .boring a set of 40 hp heads to 92 or 94 mm is asking for a hole in the cyl. Head the 40 hp heads would be to thin . To cool the motor and you would have blow buy big time .I would go with a set of 1600 cc cyls. With a 74 mm crank or a 1600 cc crank .like I said just my two cents take it or leave it lol spencerfvee..quote="bdub475"]Ok I'll start off with the fact that these are 40hp square boss heads.(PLEASE don't tell me to post in vintage speed.) This isn't a cookie cutter vintage speed build and when I ask question there I'm given the same old formula. I want to do something a little different. I do want this engine to look like a 40 horse when completed.
Here is what I have planned and mocked up so far.
40hp case with cam bearings, case savers and full flowed.
74mm c/w 1600 style crank
Narrowed 40hp rods
1600 rockers
I have a Vangaurd dual carb kit
I've mocked up the short block using stock 77mm P/C and I looks like a set of aircooled.nets 85.5mm stroker P/C will get the deck very close to stock. I'll have to have the case and heads cut, run the rods without the bushings, have the barrels cut down to get deck height set and clearance the skirts but that will get me to 1699cc. I haven't decided on a cam yet. I'm hoping for a little input there.

Ok now lets get to the heads. I plan on having 1600 size valves and seats put in as well as new guides after I'm done. I started with a good usable head, no biggie if I mess it up I have a few good sets. It's hard to take good picture of the ports so bear with me.
First picture is the head before any work was done. The screwdriver is pointed at the step or sharp 90° bend that I blended out in the second picture.

This is after blending the step almost completely out. I didn't intent to take it down that far to begin with. Will removing that much hurt air speed considering the cc of the engine and the fact that larger valves will be added?

I did do some porting throughout the whole port but I just enlarged it keeping the same shape other than the area right under the valve seat and the odd lumps and casting crap.

Next question. How much of the guide support can be removed? I see it completely smooth in dual port heads. On the intake side it doesn't seam like it supports the guide much. Does it create some sort of venturi effect or help direct the flow around the guide better or does it just simply support the guide?

The exhaust side looks to me like it's about 50% of the guide support. So I don't think I want to take too much of that away. Is there any way to make this side flow better without making the head weak in the exhaust port?

I'm not building an all out race engine. It's going in a 63 beetle and most likely will be run on the stock 4.37 gears. It will not be run hard. I just want a really peppy little engine that looks like a vintage 40 horse. I know most will say I'm wasting my time but it's what I'm going to do. I'm open to any suggestions.[/quote]

Wed Dec 03, 2014 4:56 pm

[quote="nsracing"]FVee heads are untouched. Cannot modify them at all. They only allow valve seat grind -that is about it. That is what makes it hard to have any advantage over another competitor.

Not true, Fvee heads are extensively modified. There is a spec for the intake port size and one for the valve port size, between is free. Sets do run $1500 to $2000. The intake and heads are were we get 58-60 hp out of a 40hp engine and a single 28mm carb. (And running them to 7000 rpm lol)

Thu Dec 04, 2014 1:58 am

I have some concerns about the area just inside the exhaust valve seat.

The port is a bulbous shape under the seat. The port is much bigger than the valve seat. Mainly in the area's above and below the seat. At first I thought I messed up and hogged it out but I only sanded that area with emery cloth. It is also somewhat the same in all the untouched square boss head I have.

The area where the screwdriver is pointed is much deeper then the rest of the port both upper and lower. Did vw intend to do this for some sort of scavenging affect? I think blending it out would make the port way to big.

Thu Dec 04, 2014 3:01 am

The exhaust ports on all the type-1 heads are bigger than needed. I think as far as they were concerned the seat is the control point, and the port just leads to the muffler so they made it "header" size rather than port size by usual standards.

If you put in a bigger seat and the smallest point then becomes just downstream of the screwdriver then that ls a OK setup too, but it probably is already bigger than that.

Exhaust port size should be around 75% of intake by area, and what should that be? well....certainly not much larger than the intake manifold. Start there and work you way down, I think you will see your exhaust porting is overdone already.

Thu Dec 04, 2014 3:44 am

The two "dips" you are pointing out are where the port is widened to make up for the encroaching volume of the guide boss.

The exhaust ports are not where the gains are to be made... Bill Fisher's book has some passages about porting single port intakes, or at least says that most of the twin-port mods are also good on the single port heads.

I have seen extensively ported formula Vee single-port heads, most of the work was to hog out the bowls under seats to provide a "straight" port for about 20 mm just before the valve, and increasing the diameter of the passages where the maniflods bolted on, it was a 4-bolt square port. I'm not sure how successful that engine was...

On your set-up, I would stay with smoothing out casting flaws, working aligning the manifolds, and do as much as you can afford on the seats, and a bit of unshrouding in the chambers if you're installing 85.5s.

Thu Dec 04, 2014 12:58 pm

Thanks guys. I didn't do much porting on the exhaust side at all. I just thinned the guide boss and cleaned up the casting flash.
I'm kind of up in the air on going 85.5s. I want to make sure opening the head to 93.8 head won't be to much.

Thu Dec 04, 2014 2:59 pm

I have looked at the formula vee rule book .you can only polish the intake. Ports you can not do any porting that makes the ports bigger . That's One of the reasons I don't race formula vee . There Is to many guys that bend the rules and cheat they dont take a motor apart at the track to see if it's legal or not .here in ohio . they only take the car drivers word that it is a legal motor .that's a joke .taking a guys word yea right Lol .i have seen some of these so called legal motors .so much for that here's a picture of my vanguard vee with vanguard dual carbs I am hopeing to hill climb race my vee this year 2015 and drag race my vee and do some Pilawn raceing .spencerfvee quote="satterley_sr"] nsracing wrote: FVee heads are untouched. Cannot modify them at all. They only allow valve seat grind -that is about it. That is what makes it hard to have any advantage over another competitor.

Not true, Fvee heads are extensively modified. There is a spec for the intake port size and one for the valve port size, between is free. Sets do run $1500 to $2000. The intake and heads are were we get 58-60 hp out of a 40hp engine and a single 28mm carb. (And running them to 7000 rpm lol) [img][/img]

Thu Dec 04, 2014 3:39 pm

In the F Vee world polish = porting. Valve guide bosses are cut out, ports are smoothed and shaped. There is a lot of art and science to getting the flow without sacrificing velocity. For most regional and even major races there are no teardowns to determine legality. But at the runoffs the top three are torn down. This year the top three finishers were disqualified. One for deck height and two for valve lift. ( and were are talking Being out of spec by a few thou)

Thu Dec 04, 2014 4:18 pm

I really have no idea about "V" rules, but I once had a set of Super V heads. They had grotesque ports and very high compression. Lacked one or maybe even two fins.