Head Differences?

907mge · 02-28-2010, 11:22 PM

Is there any difference between the 7m head from 90 to 91? I'm asking this because i got a head with 90k on it from a 91 na and would like to also know if would be better to use than the head that i have now with 130k on that i will be doing the hg on. Also anyone know what a used isc and cold start injector are worth?

cre · 03-02-2010, 02:37 AM

Yes, there are differences... actually there are more head revisions than there were year models and there are a few different block revisions as well. The later revisions are said to flow better and I think they had more vanes. I've never heard anything about them really gaining anyone more power though, but I'm sure there's a TINY amount to be had from a newer revision head.

They are all interchangeable though. The only thing that would need to be changed is if you're swapping from a GTE to a GE or vice versa; You'd need to swap the intake cams them and reshim... of course you should reshim for proper valve clearances anyway, it's overdue I'm sure.

907mge · 03-02-2010, 03:29 AM

thank you, i'd like to use the head from the 91 since it has less miles on it, should be fine since it was just pulled to put in a 1jz , also can you tell of a good way to clean the pistons while still in the block ?

cre · 03-02-2010, 04:17 AM

Go to a Chrysler or Dodge dealership and buy some Mopar Combustion Chamber Conditioner from the parts department. Then rotate the crank manually so all the pistons are below the block deck and spray in the cleaner liberally. Let it soak for a few hours and then wipe it out... spray in more and after a couple hours wipe it out... Letting it sit over nights works well. Personally, I prefer to take measures to keep it from getting there ro clean
em with steam while the engine is running.

907mge · 03-05-2010, 12:40 AM

got the cleaner you said about, is there any reason i should get the head tested for cracks since it was taken from a running 7mge with only know problem was a bhg?

cre · 03-05-2010, 01:54 AM

Always get the head tested... it doesn't cost much and a N/A no less likely to have damage.

907mge · 03-05-2010, 03:04 AM

they quoted $90 does that sound right

cre · 03-05-2010, 03:23 AM

$90 for what exactly? You were already having them clean and mill the head correct? Checking for cracks and vacuum testing doesn't add much to the bill in my area... I'd also have the valve stem seals replaced.

907mge · 03-05-2010, 11:23 AM

just to vaccum test it 120 for surface machined and 150 for valves reground

02-28-2010, 11:22 PM	#1
907mge 20psi boost Join Date: Dec 2009 Location: Harrisburg Posts: 759	Head Differences? Is there any difference between the 7m head from 90 to 91? I'm asking this because i got a head with 90k on it from a 91 na and would like to also know if would be better to use than the head that i have now with 130k on that i will be doing the hg on. Also anyone know what a used isc and cold start injector are worth?

03-02-2010, 02:37 AM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Yes, there are differences... actually there are more head revisions than there were year models and there are a few different block revisions as well. The later revisions are said to flow better and I think they had more vanes. I've never heard anything about them really gaining anyone more power though, but I'm sure there's a TINY amount to be had from a newer revision head. They are all interchangeable though. The only thing that would need to be changed is if you're swapping from a GTE to a GE or vice versa; You'd need to swap the intake cams them and reshim... of course you should reshim for proper valve clearances anyway, it's overdue I'm sure. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

03-02-2010, 04:17 AM	#4
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Go to a Chrysler or Dodge dealership and buy some Mopar Combustion Chamber Conditioner from the parts department. Then rotate the crank manually so all the pistons are below the block deck and spray in the cleaner liberally. Let it soak for a few hours and then wipe it out... spray in more and after a couple hours wipe it out... Letting it sit over nights works well. Personally, I prefer to take measures to keep it from getting there ro clean em with steam while the engine is running. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

03-05-2010, 01:54 AM	#6
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Always get the head tested... it doesn't cost much and a N/A no less likely to have damage. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

03-05-2010, 03:23 AM	#8
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	$90 for what exactly? You were already having them clean and mill the head correct? Checking for cracks and vacuum testing doesn't add much to the bill in my area... I'd also have the valve stem seals replaced. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

03-02-2010, 03:29 AM	#3
907mge 20psi boost Join Date: Dec 2009 Location: Harrisburg Posts: 759	thank you, i'd like to use the head from the 91 since it has less miles on it, should be fine since it was just pulled to put in a 1jz , also can you tell of a good way to clean the pistons while still in the block ?

03-05-2010, 12:40 AM	#5
907mge 20psi boost Join Date: Dec 2009 Location: Harrisburg Posts: 759	got the cleaner you said about, is there any reason i should get the head tested for cracks since it was taken from a running 7mge with only know problem was a bhg?

03-05-2010, 03:04 AM	#7
907mge 20psi boost Join Date: Dec 2009 Location: Harrisburg Posts: 759	they quoted $90 does that sound right

03-05-2010, 11:23 AM	#9
907mge 20psi boost Join Date: Dec 2009 Location: Harrisburg Posts: 759	just to vaccum test it 120 for surface machined and 150 for valves reground

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