Briggs Raptor II boom!

[Memfus_boi]

I am new to karting but I had this lovely Briggs Raptor 2. Got it up to 55mph and had to slow down around a corner then BOOM, I have a XL oil plug in the side, lol. Now its time to rebuild. I have a spare block but are my original parts in the motor stock? Any suggestions on a new build?

 

[itsid]

crank ventilation in progress...

Well, we can tell something very important:
the rod (stock or not) was NOT up for the task at hand..

so you might want to buy a billet one anyways, in order to remove that point of failure from your next equation

the raptor II for all I know had larger crank bearings than the 5hp B&S..
you might want to do some research there in order to find the correct replacement parts.

that cam to me looks reground .. but my knowledge about raptors is miniscule,
so it can be the stock raptor cam, a reground stock cam or aftermarket and I'd be unable to tell the difference w/o comparing it to a known unmodified stock cam in hand...
(short: maybe someone with a greater knowledge chimes in)

'sid

 

[landuse]

Ouch!

 

[Randy H]

That block may be patchable, with good epoxy and a piece of aluminum. Welding may induce stresses that would likely require some expensive machine work.

That rod doesn't look like A Raptor II rod. The units I've seen all had an R1 on the rod and a R2 on the cap with an integrated dipper. A small Briggs logo. But no other numbers/letters.

What are those plastic pieces in your hand? The remains of a nylon dipper?

Any chance of some more pics? Like all the rod remains, and the tag on the blower housing.

A welded lifter bore area would be a sign that at one time the engine had something other than a stock cam. Quite a few aftermarket cams had an aggressive profile that was hard on blocks. Certain racing classes required a stock lift cam. The aggressive ramp would launch the valves in a controlled manner. Slapper cams.

So lol, no answers, only questions. But here's a blast from the past.

https://web.archive.org/web/2002041...iggsracing.com:80/racing_engines/raptor2.html

 

[anderkart]

I am new to karting but I had this lovely Briggs Raptor 2. Got it up to 55mph and had to slow down around a corner then BOOM, I have a XL oil plug in the side, lol. Now its time to rebuild. I have a spare block but are my original parts in the motor stock? Any suggestions on a new build?

I'd suggest you research and post any questions you might have at this forum:
https://karting.4cycle.com/forumdisplay.php?10-Flatheads-Forever

Most of those those guys race karts with engines like yours, or professionally build racekart engines for a living. Some of them are the most knowledgeable/helpful dudes you'll find anywhere on the net

 

[Memfus_boi]

The orange pieces is the dipper. Luckily I have a spare block to rebuild with. I have a pics of the spare motor also, they are twins I guess.

 

[Memfus_boi]

Sorry, I forgot to add pics....

 

[Randy H]

Made 3/13 /96. It's A Raptor I. It came with a weak rod and a weaker steel dipper. The aftermarket came up with a nylon dipper. But the rod was still only good to about 5000 RPM.

That is a steel bore, good, saves piston compatability issues. If you need to go that far, and your spare is the same.

The Raptor II, and III models had the one piece rod and dipper. Good to 7000 RPM, if the clearances are spot on.

Best bet would be a shiny new Arc billet rod. I have some NOS Raptor II/III rods. You can PM me if interested.

The cam, if someone didn't engrave some info, is a pig in a poke. If you were happy with the cam you could reuse it, it does appear to be worn. Aftermarket a DynoCams 94ss is a good choice. It's not a slapper cam, easy on the block.

http://www.tbrwins.com/catsearch/frsearch.mgi?mgiToken=944DEH33LI1IG15H0J1

Future build is dependent on how much money and how much knowledge your willing to put your time into gaining.

There are some good posts here on the Briggs flathead, as well as karting.4cycle.com. The Jimmy Glenn book post is worth reading at least 4 times, lol.

Are you racing this or just beating the crap out of it for fun? Not that racing isn't fun, but to be competitive you probably don't want to slap in the best parts you have and hope for the best. The brand new Raptors back in the day, even though raceable right out of the box were intended to be blueprinted and tweaked by engine builders.

Parts costs add up fast, machine work, ugh! Valve guides, seats, cylinder bore. Bearings, seals.

Your spare is pretty rusty. More pics please, lol.

 

[Memfus_boi]

Its just for fun, I was wanting to beat the crap out of it. I decided to get a predator. I love the sound of the flathead but its a lot of maintenance to keep it going. Plus, driving it over 50mph scares the crap of out me in the city streets. (Memphis drivers are horrible) I was planning on swapping out most of the internals, they are kind of rusty.