Vanguard Vtwin Info: 16hp and 18hp differences

[slonomo]

Maybe this thread has already been done, but I'm needing to know about these engines. I bought a 16hp recently and would like to "EDJUMCATE" myself. Not really finding what I want on the net.

(Q) What are the differences between the 16hp and 18hp versions?

(Q) Will the same mods work for either one?

(Q) Will the parts interchange?

(Q) What are the standard stages of power mods?


Thanks in advance for your info. Please copy and paste the questions and answer in red. Maybe we can use this as a sticky if it's clean enough.

[1989Marathon]

14hp=29cu.in.
16hp=30cu.in.
18hp=35cu.in.
20hp=35cu.in.

(Q) What are the differences between the 16hp and 18hp versions?
(A)
The 14 and 16 have the same bore and stroke, different carburetors. I haven't been able to figure out why they are labeled as different displacements unless it was a marketing thing. Briggs has a lot of ambiguity in this area. They both came stock with the steel sleeves inside the exhaust ports. That is not the reason for the different rating. The only two 14 motors I have seen came with 30cuin heads on them, stock, so I think they used the same heads. All 30 heads are not created equal. The difference is in the mounting surface for the rocker shafts. Generation 1 and 2 rockers used a flat mounting surface. Generation 3 rockers used a keyed pad.
18/20 motors have a larger bore(same bore on each) and a slightly longer stroke. The cranks from the 14/16 do not interchange with these motors, although they do fit. 18 and 20 had different carbs, and a 2-barrel carb was available on the 20hp.

(Q) Will the same mods work for either one?
(A)
The same mods will work on all motors from 14-20hp. Once you step up to the 23hp motor, things are slightly different. The heads interchange between the two series, but you need the intake manifold that was designed for those particular heads. The head ports are at a different location, thus making the distance different. The 23 cam will fit 14-20 motors.

(Q) Will the parts interchange?
(A)
See above

(Q) What are the standard stages of power mods?
(A)
1. Rev-kit(including flywheel advance key) and governor removal. Billet pushrods. Cam advanced one tooth.
2. 16hp heads with generation 1 aluminum shaft rockers. Heads milled depending upon the type of head gasket used. Heads ported.
3. 2-barrel intake/carb.
4. Either a $60 stock 23 cam or a $220 performance cam installed straight up. The performance cam is well worth the money if you can afford it.

If you want a motor that breathes a lot better at the higher rpms, the 23 heads are the way to go. For low-end torque, I go with the 16 heads.

[bokeasmowl]

That last question and answer sounds alot like my motor...sweet.

[Dave in VA]

Not to hijack, but I've got a Vanguard related question.

Why is the 24 Intek @724cc on my Husqvarna so much larger than the 23 Vanguard @ 625cc?

[slonomo]

Originally Posted by 1989Marathon

14hp=29cu.in.
16hp=30cu.in.
18hp=35cu.in.
20hp=35cu.in.

(Q) What are the differences between the 16hp and 18hp versions?
(A)
The 14 and 16 have the same bore and stroke, different carburetors. I haven't been able to figure out why they are labeled as different displacements unless it was a marketing thing. Briggs has a lot of ambiguity in this area. They both came stock with the steel sleeves inside the exhaust ports. That is not the reason for the different rating. The only two 14 motors I have seen came with 30cuin heads on them, stock, so I think they used the same heads. All 30 heads are not created equal. The difference is in the mounting surface for the rocker shafts. Generation 1 and 2 rockers used a flat mounting surface. Generation 3 rockers used a keyed pad.
18/20 motors have a larger bore(same bore on each) and a slightly longer stroke. The cranks from the 14/16 do not interchange with these motors, although they do fit. 18 and 20 had different carbs, and a 2-barrel carb was available on the 20hp.

(Q) Will the same mods work for either one?
(A)
The same mods will work on all motors from 14-20hp. Once you step up to the 23hp motor, things are slightly different. The heads interchange between the two series, but you need the intake manifold that was designed for those particular heads. The head ports are at a different location, thus making the distance different. The 23 cam will fit 14-20 motors.

(Q) Will the parts interchange?
(A)
See above

(Q) What are the standard stages of power mods?
(A)
1. Rev-kit(including flywheel advance key) and governor removal. Billet pushrods. Cam advanced one tooth.
2. 16hp heads with generation 1 aluminum shaft rockers. Heads milled depending upon the type of head gasket used. Heads ported.
3. 2-barrel intake/carb.
4. Either a $60 stock 23 cam or a $220 performance cam installed straight up. The performance cam is well worth the money if you can afford it.

If you want a motor that breathes a lot better at the higher rpms, the 23 heads are the way to go. For low-end torque, I go with the 16 heads.

EXCELLENT INFO!!!

[1989Marathon]

That's just the high-level breakdown. If you need more specifics on anything, let us know. Welcome to the dark side!

[slonomo]

Don't welcome me yet.....LOL The engine is still sitting in my trailer.

The good news: my clone is giving me fits, it won't stay running. I think it sheared the timing key again. Looks like I might be installing this sooner than later!

[1989Marathon]

Originally Posted by slonomo

Don't welcome me yet.....LOL The engine is still sitting in my trailer.

You're gonna wish it didn't sit in the trailer for so long...

[slonomo]

I just read through Boke's thread. Don, you are the man! I'm thinking I need to put the seat belt on the Briggs and take a drive to NY!!! Do you have a full shop out there? I'm thinking I like what you did to Boke's engine. It runs really smooth man. But....one thing....I really don't like yellow... I'm thinking OD Green.

[1989Marathon]

Nope. I only do yellow. Sorry.
I do it out of my garage. I have everything I need except for a mill. I need to visit my brother for that.
Boke's motor is the nastiest Vanny I have ever seen. I offered to buy it from him but he declined. If he can get his clutching right, he will have a hand-full.