Post by tasilloracing76 on Dec 27, 2005 12:34:53 GMT -5
We've gotten more speed out of our Slingshot only by making sure the car isn't bound up due to set-up, stagger, etc, etc, etc. And by the way, just because it rolls free; straight, doesn't mean it may not be bound up in the turns. Also perhaps, the gearing is wrong for a given race night..... more on all this later. If I suspect the problem is with the engine, and assuming the carb, plugs, timing and valve train is OK ( more later on those subjects ) the next thing I look for is a blown head gasket. Given the RPMs we twist these things at, the head gasket is definitely a weak link ( as it is on any racing engine ).
To check for this, it's simply a matter of removing the blower cover to allow access to the head gaskets. DON'T DO THIS CHECK BY RUNNING THE ENGINE ! ! ! Instead, with the spark plugs in tight, apply some soapy water around the head gasket. This is the gasket between the heads and the block, below the headers and intake manifold. MANUALLY rotate the engine in the direction of travel and watch for bubbles indicating a leak anywhere around the head. Note that even though the leak may be small, and the engine may hit the desired RPM; you are loosing compression and thus HP. The first symptom of a bad head gasket is elevated temperature of the head that is leaking since the leak causes that cylinder to run lean. Pay close attention to your head temp as it should generally never go above 300 degrees F. Be aware that your head temp sensor is on the cylinder closet to the firewall so you would need to carefully touch the cylinder heads and compare their relative temperature in order to gauge whether the rear cylinder is running hot....." be careful not to burn yourself! ! !" Repair is obviously done at the Tobias shop since the cylinders are sealed. They do a very good test of leakdown and compression prior to making the repair, insure the head is not warped and if so have it milled. The cost of having this done is very reasonable and a whole lot cheaper than waiting until things get so hot that they seize up.
Ed
To check for this, it's simply a matter of removing the blower cover to allow access to the head gaskets. DON'T DO THIS CHECK BY RUNNING THE ENGINE ! ! ! Instead, with the spark plugs in tight, apply some soapy water around the head gasket. This is the gasket between the heads and the block, below the headers and intake manifold. MANUALLY rotate the engine in the direction of travel and watch for bubbles indicating a leak anywhere around the head. Note that even though the leak may be small, and the engine may hit the desired RPM; you are loosing compression and thus HP. The first symptom of a bad head gasket is elevated temperature of the head that is leaking since the leak causes that cylinder to run lean. Pay close attention to your head temp as it should generally never go above 300 degrees F. Be aware that your head temp sensor is on the cylinder closet to the firewall so you would need to carefully touch the cylinder heads and compare their relative temperature in order to gauge whether the rear cylinder is running hot....." be careful not to burn yourself! ! !" Repair is obviously done at the Tobias shop since the cylinders are sealed. They do a very good test of leakdown and compression prior to making the repair, insure the head is not warped and if so have it milled. The cost of having this done is very reasonable and a whole lot cheaper than waiting until things get so hot that they seize up.
Ed