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Bill Stock
New member
Username: Tripleguy
Post Number: 2
Registered: 01-2007
Posted From: 156.76.147.55
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 02, 2007 - 05:30 pm: | 
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Considering a rev kit for my 18 HP Vanguard. Anyone install one? How difficult was it to install and how happy are you with the results? Any advice you could lend would be appreciated.
Thanks |
Rogersmith
Advanced Member
Username: Rogersmith
Post Number: 234
Registered: 01-2005
Posted From: 75.50.23.188
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 02, 2007 - 09:00 pm: |
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I was going to do that until I found a better source for parts. Their rev kit is for a certain class of racing where you can't change the valve springs, so Performance V Twins offers the fat aluminum pushrods, valve spring SHIMS(no springs), strong spring retainers, and an offset flywheel key that advances the ignition timing. It's an OK deal, but was going to cost about $112 shipped.
The stamped steel spring retainers are the weakest thing in the engine and have to go before more spring pressure is added.
I found retainers and dual springs for $40, replaced the weak stock aluminum intake pushrods with steel exhaust pushrods for $2.50 ea. From a guy/company who race small engines, karts, riding lawn mowers. 40-45 HP from an 18/20 hp vanguard block @ 7000 rpm, and a dependable engine too. They do use $325 roller rocker arm sets from Performance V twins.
If you're not going to change the cam the rev kit is fine other than a litle overpriced. You might ask them if they'd sell the retainers and shims without their pushrods.
If you go with my supplier I'd only use the outer spring of the dual spring set with a stock cam.
Basically what you're doing is making it safe to run without a govenor, and keep the valves shut. I'm certain the weak springs are an intentional designed in rpm limiter.
http://www.heymow.com is a racing mower site and you can read the Vanguard section.
Company is E.C. Distributing 615-446-6807 Tennesee
Ask for George Herrin |
david berger
Senior Member
Username: Davidrrrd
Post Number: 507
Registered: 01-2005
Posted From: 72.85.143.149
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 03, 2007 - 08:44 am: |
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Tim Schotanus put a rev kit into his maxIV,
he replaced his 16 hp with a 23ph block and a rev kit with the heavy duty conecting rod and chrome molly pushrods, shims and spring retainers,,ect.ect.
thin head gasket also
he did not replace the cam,
it runs great! |
Jack Ouellette
Member
Username: Beungood
Post Number: 46
Registered: 02-2005
Posted From: 152.163.100.199
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 03, 2007 - 09:41 am: |
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How Much more power is put out? Whayt kind of performance gains? Reliability? |
david berger
Senior Member
Username: Davidrrrd
Post Number: 508
Registered: 01-2005
Posted From: 72.85.143.149
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 03, 2007 - 12:31 pm: |
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well compaired to the two strokes of old that had a power stroke every reveloution and could soar to rpm's sometimes in the 8000's and up,
and had suficiant tork along with them to do the job nicely,
well the comparison for the four strokes is a dismal one!
sure they have great relyability,
(exept when they don't)
and tork out the yingyang- up till the 3500-4000 rev limit, then it's done and there aint no more!
now plenty of peopla would be happy to travel slowly but surely within reason,
but the four stroke lawn mower engines they use theas days are way to short on quality and performence,
quality = i speek of the before mentioned in this tred cheep valve train components that rob them of there prespective preformence and could also fail if pushed for gains in rpm.
Thus the rev kit's nesesity,
for the relyability if for nothing else everyone should have it done!.
(once there warentee expires of course)
whats the worst thing that could happen if you had some extra rpm waiting on tap?
one needs only to examine an old video of tim schotanus powering out of ramonas mud hole over at humphrey to see for themselfes that tork wasent what got him out when otheres would slide back at the last moment, it was thoughs extra rpm's that made his maxIV sucsessful,
and won him every water crossing event he entered as well!
he did start with more displacement but you can still see my point right? |
Rogersmith
Advanced Member
Username: Rogersmith
Post Number: 235
Registered: 01-2005
Posted From: 76.211.65.64
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 03, 2007 - 05:56 pm: |
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If starting with a 23 hp vanguard you have a lot more potential than a 14-18 vanguard. The heads are different along with a .150" bore over an 18/20 hp. The 20 and 23 have 2 barrel carbs. There is still plenty of power lurking in a 14/20 hp. All a rev kit will do is the first step in making it turn a little more rpm safely. If you were governed at 3600 now you can run 4600 before the stock cam calls it quits, at least the spring shims will keep the valves on their seats to around 5000.
I would like to try basically Tim's 23 hp build on a 18 and see what it put out. Valve train parts. Up the compression. Clean up the ports and put a decent exhaust on it. Well I already did that except I changed the cam. Which I love, but once the stock cam is gone(with the built in compression release), you are obligated to buy a real starter to turn the thing over. Cam and starter=$400.
So the idea of upping the compression, valve train stuff, better fuel and a little timing advance and decent exhaust are the other main performance ideas without spending more serious $.
18hp stock is 8.5 compression. Thin head gaskets will make it 9, which 93 octane should make it happy. Then mill the heads, or change the rod/piston to get the compression up to whatever you want. I run 100 octane now. I found a real octane booster with tetraethel lead that adds a dollar per gallon cost.
For people with more time than $ that like to wrench, it's great. For others, buying and being happy with a stock 23hp, maybe with the 50amp charging system and using low octane gas is more appealing.
Reliability? Well as a disclaimer, once you do anything it's a risk. What is the risk? Built to the level of intended use, it's very reliable. The guy who taught me races riding lawn mowers, or what once were riding lawn mowers. He has a few national championships and says the vanguard holds up better than any other engine he's seen. He's class limited to the 20 hp block, and has dyno'd them at 40-45 hp. His "mower" has been clocked at 92 mph. Makes power to 7000, and has seen 9000 rpm at the end of straight away when geared too low for a lap. That's with a stock block, crank, and piston and stock steel pushrods. Also with $230 rods, $325 rocker arms, $300 flywheel that won't fly apart. Head work, etc. |
Rogersmith
Advanced Member
Username: Rogersmith
Post Number: 239
Registered: 01-2005
Posted From: 76.211.65.64
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 03, 2007 - 09:36 pm: |
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OK, now I'll answer Bill's question. To install the rev kit, you need compressed air into the spark plug hole to hold the valves shut while you remove the springs.
To use the included modified flywheel key(or grind your own) the flywheel has to come off. Needs a puller. Part of the key is ground away so the flywheel can rotate forward, advancing the spark timing. The key is for locating only, the tapered fit of the wheel on the crank is what holds it in place. |
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