Which headbolts?

GAMAYBERRY

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I am rebuilding my MerCruiser 4.3 V6 and have one more question. Is there any reason not to use the FelPro headbolts over the ARP high performance ones? There is a huge difference in cost. I dont want to skimp on it, but it seems the ARP ones are mostly used in building race engines. Anything I'm overlooking?
 

matt167

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Re: Which headbolts?

OEM Mercruiser headbolts will be off the shelf GM parts.. Felpro will be fine. ARP is made to military specification and that's why it's so expensive.
 

GAMAYBERRY

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Re: Which headbolts?

FelPro would be staying with OEM, I was just wondering if there was any huge benefit to spending $135 more dollars on the headbolts. lol
 

matt167

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Re: Which headbolts?

Not unless you were supercharging or planning on running high RPM. Just use the Felpro.
 

Bondo

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Re: Which headbolts?

I am rebuilding my MerCruiser 4.3 V6 and have one more question. Is there any reason not to use the FelPro headbolts over the ARP high performance ones? There is a huge difference in cost. I dont want to skimp on it, but it seems the ARP ones are mostly used in building race engines. Anything I'm overlooking?

Ayuh,.... What's the matter with the head bolts ya took outa the motor,..??
 

GAMAYBERRY

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Re: Which headbolts?

Ayuh,.... What's the matter with the head bolts ya took outa the motor,..??


They are stretch bolts, reuse them and you will blow head gaskets right away. They are one-time use bolts.
 

achris

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Re: Which headbolts?

They are stretch bolts, reuse them and you will blow head gaskets right away. They are one-time use bolts.

The head bolts for a 2000 4.3 are not TTY.... The service manual states quite clearly that you can clean the bolts and re-use them... Page 3A-42, point 4 of 'Cleaning and Inspection'.

Chris.......
 

GAMAYBERRY

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Re: Which headbolts?

The head bolts for a 2000 4.3 are not TTY.... The service manual states quite clearly that you can clean the bolts and re-use them... Page 3A-42, point 4 of 'Cleaning and Inspection'.

Chris.......

Oh I have seen that, but this is one time that I feel like you shouldn't always follow directions per a manual. Once you add the 55? stretch (and yes it is different for each set of bolts) that bolt is in essence "stretched." I have seen folks re-use them and get away with it, but I have also seen the other option take place. When you are $700+ into a rebuild, why not just spend the money to do it right and not cut corners? I also am one that replaces the timing cover each time it is removed (like it says). :D
 

achris

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Re: Which headbolts?

Oh I have seen that, but this is one time that I feel like you shouldn't always follow directions per a manual. Once you add the 55? stretch (and yes it is different for each set of bolts) that bolt is in essence "stretched." I have seen folks re-use them and get away with it, but I have also seen the other option take place. When you are $700+ into a rebuild, why not just spend the money to do it right and not cut corners? I also am one that replaces the timing cover each time it is removed (like it says). :D

No arguing your logic... However, I would like to point something out. When you turn the bolts through 55 degrees, I wouldn't mind betting that the final torque on them is going to be around 80ft-lb.... WAY less than stretching torque....

Have fun with the new bolts.... ;)

Chris......
(and yes, I replace that horrid plastic cover every time too :facepalm:)
 

m_steiger

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Re: Which headbolts?

You will be 100% fine reusing the stock head bolts, just clean them up and oil the threads when torquing the bolts. If you did wanna go ahead and replace them for piece of mind insurance, felpro bolts will do the job perfectly. ARP would be overkill for what you need.
 

Bondo

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Re: Which headbolts?

They are stretch bolts, reuse them and you will blow head gaskets right away. They are one-time use bolts.

Nope,.... They're Not torque to yield bolts,...

Yer confusin' Torque settin's with bolt stretch,... 2 Very different things,...

I bought my 1st torque degree wheel, Years ago, doin' Caterpillar head bolts,...
Those aren't/ weren't TTY bolts either,...
Just the torque settin' is achived by torque, 'n degrees,...
 

matt167

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Re: Which headbolts?

Exactly. Same thing with many Subaru's.. They just get their final torque setting from the angle.

Found this old diagram from an old Iboats thread.
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