SBC Tappet Clearances

SBC Tappet Clearances

Author
Discussion

Nabbott

Original Poster:

294 posts

135 months

Friday 4th July 2014
quotequote all
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

F.C.

3,896 posts

207 months

Friday 4th July 2014
quotequote all
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.

Nabbott

Original Poster:

294 posts

135 months

Friday 4th July 2014
quotequote all
So I agree entirely with your logic and thought process - but it still begs the question, why the hell do they tell you to adjust when hot?

Boosted LS1

21,165 posts

259 months

Friday 4th July 2014
quotequote all
Because the hot setting is when the engines running and temps are by and large controlled by the thermostat. On the other hand, what temp is a cold engine? The spectrum goes from almost freezing to getting warm.

The hot engine will have everything expanded to the running clearances.


ROWDYRENAULT

1,270 posts

213 months

Friday 4th July 2014
quotequote all
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

ROWDYRENAULT

1,270 posts

213 months

Friday 4th July 2014
quotequote all
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

Nabbott

Original Poster:

294 posts

135 months

Friday 4th July 2014
quotequote all
Remote starter just purchased. Whining over smile

T-Rev

109 posts

277 months

Saturday 5th July 2014
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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

Nabbott

Original Poster:

294 posts

135 months

Sunday 6th July 2014
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Thanks Trevor. I've actually read this article, you're right it is very helpful! I'm going to try (one more time) 'hot with a remote starter before I succumb to the logic and maths in the article.

Whereabouts are you in the south east btw?


T-Rev

109 posts

277 months

Friday 11th July 2014
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Hi Nigel, I'm near St Leonards/Hastings, how about you?

Nabbott

Original Poster:

294 posts

135 months

Saturday 12th July 2014
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T-Rev said:
Hi Nigel, I'm near St Leonards/Hastings, how about you?
Ascot, Berkshire. Took the car out today and got sun burnt and very hot wink

Storer

5,024 posts

214 months

Saturday 12th July 2014
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Most Can-Am owners look like they spend their lives in a tanning booth anyway.............


Paul

V8Dom

3,546 posts

201 months

Sunday 13th July 2014
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you think thats bad, we used to adjust them while running on the 289 race ford engines..

i do mine cold

dom