Originally Posted by
Brokeagain
ok I got this promo package some time ago. I Have maybe 4 1/2 gal's give a tank or two on my Tune line GRP...mind you this came with the key chain the Team Towel the really nice GRP pipe and manifold. Ok so I figure it's time to send the piston and sleeve off to get a nice clean up and a real good resizing.I bought some new bearings (ceramic) and figured I'd be good for another season. well I open this engine up and it has a squared off con rod its not even knife edged. and the crank is flat on the back, it looks like a real poor turbo job on the crank flute. But it has the dished piston and it looks like a 5 port slevee from GRP. can anyone enlighten me on what GRP this mite be?? Oh and the carb is a GRP but its backwards the idle screw is on the bottom....anyone seen this????
Did you buy new or used? If you bought used, there is a good chance you may have gotten a sport line .21 with the turbo button/cooling head exchange. Back when I was the GRP go to guy, that was a very popular thing to do. Alot of people wanted to run the turbo plug on their sport line engines and the only way to do it was to switch the sport/sport rally head with the tuned line head as the head and button were machined as one in the sport line and they used standard plugs. Things to look for to figure out if it is sport or tuned or a mix of both are:
-sport crank will be a solid cheek with no fluting unless modified
-sport crank will also have a solid steel intake ramp where the tuned crank will be drilled and filled with silicone
-sport crank will be silver and non-hardened where as the tuned line will be darker in color from the hardening process
-sport sleeve will be a 5 port like the tuned line but will not have the tear drops in the front transfer like the tuned line had
-sport rod is non-knife edged where the tuned line was
-sport case did not have the rear booster port relieved at the base where the tuned line had 2 reliefs cut into the base of the rear booster to allow the incoming charge easier access to the rear booster port area
-sport carb had idle screw located on the front of the carb body and tuned line was on the backside of the carb body
Those are the main differences. The differences between the sport and sport rally editions was the rally had a triple exhust port similar to the onroad engine with similar port timing specs as the onroad version. As mentioned, if you have pictures and a better description of where you got the engine and in what condition may help us determine what is going on.