Raptor block questions

racer223

Member
I've got five or ao flathead's and I am not sure how to tell them all apart. One block has a smooth outter casting appearance, two have a rough outter casting appearance. And all the others seem to be non raptor blocks. I remember from the KT's that the smoother the casting the later the motor, same idea here? And finally, which is better? Thanks.
 

95 shaw

Premium User
In the early/mid 90's, Briggs began media blasting the blocks. (Builder heyday, techman bugaboo).

Original pressure cast blocks had a smooth appearance.

This was before any of the raptor series.
 

racer223

Member
We're looking to get some limited modified racing going again in the Southwest. I've never played too hard with the flattys. Curious which blocks to go with. I have a dual bearing block, but when you look between the fins you can see cylinder wall .... That can't be good, and likely not repairable.
 

95 shaw

Premium User
I always raced cool bore emgines, as those we thought to produce better power at the time.. only owned 1 dual bearing engine.(the only one i did not build myself. An eye opener!)

I became the local repository for used up fertilizer pump engines.
I have a half dozen virgin bushing cool bore blocks, most without, or bushing side covers.
Make a real deal on the lot to clear space for other projects.

The flatheads have been disallowed in our area., even in most open classes.
 

CarlsonMotorsports

Premium User
Disallowed? For shame!
:)

OP,
If you are building a limited, you may want to start with a single bearing block with the DU bushing on the flywheel side -- dual bearing blocks have a problem of cracking in the oil drain back passage below the main bearing on the flywheel side. It can be reinforced (welding) but with so many good donor blocks around, I wouldn't go that route.

IMO, you will want a steel sleeve engine (stock or sleeved cool bore) as their are current limitations on stock of coated pistons (Wiseco/other.)


The R4 blocks will have a substantially thicker lifter bore area (re-enforced/extra material casting around the ex lifter that requires no welding.)
Pay no attention to the finish of the block - there have been MANY variations through the years. Smooth castings were most popular back in the early '80s.
Quick ID of the 135 series fat blocks is the extension between the ports and the top of the valve spring chamber. Also, the intake will have 3 bolt holes rather than 2. These 135 "fat blocks" make better builds because there is more material used around the sleeve as well, making them more stable once they get hot.

If there is anything that you need for your build(s), give us a call - we probably have it in stock.
I WILL be the last man standing (and supporting) the flatheads!


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 

racer223

Member
Brian,
Is there a measurement I would be looking for between the ports and spring chamber? Or something visual. I can see something visually different, but want to make sure. Also, are sleeves still available? I don't believe these blocks are sleeved. They are retired Jr dragster engines. Kids move up, and the raptor blocks get shelved.
 

racer223

Member
And cam suggestion? 1/5 mile, 3* bank, not much bite usually. ill probably roll across the scales at #380
 

OVALTECH1

Member
I like the 110 regular grind and the 112 alt myself. The 112 pulls hard down low and never seems to quit. The 110 is similar mid and top and is a good all around hard to beat cam. Just my 2 cents and that ain’t worth much. Brian will get the straightened out for sure
 

CarlsonMotorsports

Premium User
We have hardened sleeves in stock that can be align bored back to standard piston bore size. if you wish.
Hard to beat the 112-alt for short tracks and is relatively easy on the valve train.

I just finished a 458 engine this week and it was a "bugger" to clearance everything to roll over. :)
 
We have hardened sleeves in stock that can be align bored back to standard piston bore size. if you wish.
Hard to beat the 112-alt for short tracks and is relatively easy on the valve train.

I just finished a 458 engine this week and it was a "bugger" to clearance everything to roll over. :)
Yep, throw in a stroker crank and then watch stuff get really in the way.
 

flattop1

Dawg 89
Watch the center of the cam dosen't get too thin .
Be sure your lifters have a radius on them and not a square edge .
 
Yea , the 7/8 journal does help but I still have trouble with the stroker rods hitting the exhaust lifter. any suggestions.
 
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CarlsonMotorsports

Premium User
You can take a small chamfer off of the the edge of the lobe (no more than necessary.
112-alt is considerably easier than 126 to clearance, but you won't get the performance from a big cubic inch motor -- it's designed for a more mild build (small valve, stock stroke, small carb) and short track grunt.
 

racer223

Member
We have hardened sleeves in stock that can be align bored back to standard piston bore size. if you wish.
Hard to beat the 112-alt for short tracks and is relatively easy on the valve train.

I just finished a 458 engine this week and it was a "bugger" to clearance everything to roll over. :)
I am only interested in a stock stroke long rod deal. What would it cost to sleeve the block and get me a fresh valve job?
 

flattop1

Dawg 89
Last I remember there were 2 different diameters .
Seems like .875 and one inch .
Hopefully Mr Carlson will confirm or deny this .
 
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