SBC Tappet Clearances
Discussion
So I've been putting off doing this until today as the instructions are very deliberate - TAPPETS MUST BE ADJUSTED WHEN THE ENGINE IS HOT - more critical I believe as my block and heads are aluminium.
Obviously doing this hot is very uncomfortable - I have to drop the plugs (not easy around the red hot headers, then push the car in gear to rotate the engine. BUT how long do I have to adjust the tappets before the engine is too cool?
What are other peoples experiences of this hideous maintenance chore?
THANKS
Obviously doing this hot is very uncomfortable - I have to drop the plugs (not easy around the red hot headers, then push the car in gear to rotate the engine. BUT how long do I have to adjust the tappets before the engine is too cool?
What are other peoples experiences of this hideous maintenance chore?
THANKS
Nabbott said:
So I've been putting off doing this until today as the instructions are very deliberate - TAPPETS MUST BE ADJUSTED WHEN THE ENGINE IS HOT - more critical I believe as my block and heads are aluminium.
Obviously doing this hot is very uncomfortable - I have to drop the plugs (not easy around the red hot headers, then push the car in gear to rotate the engine. BUT how long do I have to adjust the tappets before the engine is too cool?
What are other peoples experiences of this hideous maintenance chore?
THANKS
I'd measure one "loose" tappet when hot and adjust it, let it cool down to ambient, measure again and use the difference to create a ratio "hot to cold" and adjust the rest cold using that formula.Obviously doing this hot is very uncomfortable - I have to drop the plugs (not easy around the red hot headers, then push the car in gear to rotate the engine. BUT how long do I have to adjust the tappets before the engine is too cool?
What are other peoples experiences of this hideous maintenance chore?
THANKS
After getting the car to normal temp remove the coil to distributor lead. Remove the valve covers. Leave the plugs in use a remote start switch to turn the motor.set the intake valve as the exhaust just begins to open. Set the exhaust as the intake valve is just short of closing. Remember if you have a flat tapped lifter cam combo you need to use an oil for that application with zinc in it. After all that quit whinning
After getting the car to normal temp remove the coil to distributor lead. Remove the valve covers. Leave the plugs in use a remote start switch to turn the motor.set the intake valve as the exhaust just begins to open. Set the exhaust as the intake valve is just short of closing. Remember if you have a flat tapped lifter cam combo you need to use an oil for that application with zinc in it. After all that quit whinning
Hi Nigel, I feel I should comment on your post based on my own experience and knowledge as follows;
I run an 'old school' modified SBC with roller rockers and up and over headers making tappet (or valve-lash) adjustment 'when hot' impossible, unless you have the engine out on a test bed!
In addition, specifically on performance engines, you can also use tappet/valve-lash adjustment to tweak performance for a particular application as desired e.g. a smaller gap will give more top end speed.
As a consequence of my set up, I have had to compensate with cold settings - this is not as straight forward as you might think and there could be a considerable risk? You must also consider the material components of your engine - as different configurations will impact on their combined thermal expansion.
As a guide, might I suggest you consider using the information provided on this web site which I believe is very helpful and informative - obviously this is only for guidance. I have set my tappets using this guidance on cold settings and allowance for top end speed without any issues (touch wood)!
http://www.centuryperformance.com/valve-adjustment...
P.S. I'm also in the South East if you want to PM me.
Best regards and good luck,
Trevor
I run an 'old school' modified SBC with roller rockers and up and over headers making tappet (or valve-lash) adjustment 'when hot' impossible, unless you have the engine out on a test bed!
In addition, specifically on performance engines, you can also use tappet/valve-lash adjustment to tweak performance for a particular application as desired e.g. a smaller gap will give more top end speed.
As a consequence of my set up, I have had to compensate with cold settings - this is not as straight forward as you might think and there could be a considerable risk? You must also consider the material components of your engine - as different configurations will impact on their combined thermal expansion.
As a guide, might I suggest you consider using the information provided on this web site which I believe is very helpful and informative - obviously this is only for guidance. I have set my tappets using this guidance on cold settings and allowance for top end speed without any issues (touch wood)!
http://www.centuryperformance.com/valve-adjustment...
P.S. I'm also in the South East if you want to PM me.
Best regards and good luck,
Trevor
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