Torque-to-Yield (TTY) Head Bolts on Mercruiser 7.4 in 1991 ???

[tpenfield]

I am in the process of doing a top-end rebuild on my 1991 Mercruiser 7.4L (oval ports) 330 hp.

I am not sure if the head bolts used 20 years ago were the TTY kind. I plan on purchasing a new head bolts for re-assembly, but the removal of TTY bolts may be a bit more tricky than 'standard' head bolts.

Does anyone know for sure, I searched my manual (#15) a bit, but did not see anything definitive ??

Thanks in advance.

 

[Don S]

Re: Torque-to-Yield (TTY) Head Bolts on Mercruiser 7.4 in 1991 ???

They are not TTY bolts and can be reused if not damaged.

I plan on purchasing a new head bolt head

What is a head bolt head?

 

[tpenfield]

Re: Torque-to-Yield (TTY) Head Bolts on Mercruiser 7.4 in 1991 ???

They are not TTY bolts and can be reused if not damaged.



What is a head bolt head?

Bad typing, Don, that's all.

There are a couple that have some bad rust on the heads (the ones along the exhaust manifold joint). So, I'll probably have to get a few bolts.

 

[stackz]

Re: Torque-to-Yield (TTY) Head Bolts on Mercruiser 7.4 in 1991 ???

take a wire wheel to the rust, once they are cleaned up if they still fit snug in the socket I'd reuse them.

for future reference, TTY bolts come out just as easy or the same as regular bolts, just cant be reused due to the stretch upon final torque.

 

[TilliamWe]

Re: Torque-to-Yield (TTY) Head Bolts on Mercruiser 7.4 in 1991 ???

t...TTY bolts come out just as easy or the same as regular bolts, just cant be reused due to the stretch upon final torque.

True and false. They come out just the same. They can be reused if they aren't beyond the acceptable length.