7AG Block, Is there a best?

User avatar
Jester_Borris
Posts: 8
Joined: Fri Jan 11, 2013 10:20 pm

7AG Block, Is there a best?

Postby Jester_Borris » Sat Jun 08, 2019 10:09 pm

Hello,

I am looking to revive my 20V AE86 and I am considering a 7A build. I was wondering if there was a better model to source from. There are many differences in the 4A blocks depending on the model they are found in and I was wondering if the same were true of the 7A. Any guidance on this matter will be appreciated.

-Borris
1986 AE86 - 20V Silvertop 4A-GE w/ Blacktop ECU

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


sirdeuce
Club4AG Pro
Posts: 661
Joined: Mon Jan 14, 2013 9:47 pm
Location: Sierra Nevada foothills

Re: 7AG Block, Is there a best?

Postby sirdeuce » Sun Jun 09, 2019 10:43 am

The latest model possible. Supposedly there is a 7A block that has oil squiters, I haven't seen one. Look to the '98 Celica as the corolla was not a "performance" engine(don't see how it would matter here). I can give you a 'go look at this' thing for your build. If you are using the 4AG oil pump look at the oil hole in the block and the oil outlet hole in the oil pump, they don't line up. It's a restriction. Outside of that I haven't really come across any issues that would steer me away from any particular block.
One shot, one kill.

sirdeuce
Club4AG Pro
Posts: 661
Joined: Mon Jan 14, 2013 9:47 pm
Location: Sierra Nevada foothills

Re: 7AG Block, Is there a best?

Postby sirdeuce » Sun Jun 09, 2019 10:45 am

If you have the funds, and a GOOD machine shop, have the oils squiters from a 4AG installed.
One shot, one kill.

User avatar
Jester_Borris
Posts: 8
Joined: Fri Jan 11, 2013 10:20 pm

Re: 7AG Block, Is there a best?

Postby Jester_Borris » Sun Jun 09, 2019 2:00 pm

The oil pump alignment issue is worthy to note. Any block ribbing variations like you see in the 4A?

If it is helpful for you to know my considerations I will list the majority below

7a Block
20v oil pump (bt w/ static tensioner)
Block girdle
20v pick up tube
All ARP hardware
20v Blacktop head
Forged rods
Forged pistons
8000rpm often

I am familiar with the timing system changes, brackets, etc. interested in the block and any differences that would make a more desirable source.
1986 AE86 - 20V Silvertop 4A-GE w/ Blacktop ECU

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


User avatar
oldeskewltoy
Club4AG MASTER
Posts: 1898
Joined: Wed Jan 09, 2013 4:44 pm
Location: Portland, Oregon

Re: 7AG Block, Is there a best?

Postby oldeskewltoy » Sun Jun 09, 2019 2:12 pm

If you are serious.... you can "fix" the 4AGE oil pump for better alignment in use for a 7A... the cost isn't cheap. The existing hole gets welded shut, and you drill a new hole that aligns with the oil port in the block.............
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

sirdeuce
Club4AG Pro
Posts: 661
Joined: Mon Jan 14, 2013 9:47 pm
Location: Sierra Nevada foothills

Re: 7AG Block, Is there a best?

Postby sirdeuce » Sun Jun 09, 2019 2:33 pm

On the oil pump hole alignment. Welding and drilling is unnecessary. Aisin makes a gasket with an oval hole and a little porting in the block and pump housing is all that is necessary, just a port matching. No sense in taking a chance on warping the oil pump housing with the heat associated with welding.

Try looking at Matrix Garage's site, I believe Yoshi did an article on this issue.
One shot, one kill.

User avatar
oldeskewltoy
Club4AG MASTER
Posts: 1898
Joined: Wed Jan 09, 2013 4:44 pm
Location: Portland, Oregon

Re: 7AG Block, Is there a best?

Postby oldeskewltoy » Mon Jun 10, 2019 7:10 am

sirdeuce wrote:On the oil pump hole alignment. Welding and drilling is unnecessary. Aisin makes a gasket with an oval hole and a little porting in the block and pump housing is all that is necessary, just a port matching. No sense in taking a chance on warping the oil pump housing with the heat associated with welding.

Try looking at Matrix Garage's site, I believe Yoshi did an article on this issue.



You can take advice from yoshi.... I'll continue to take advice from Loynings...... :D
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

sirdeuce
Club4AG Pro
Posts: 661
Joined: Mon Jan 14, 2013 9:47 pm
Location: Sierra Nevada foothills

Re: 7AG Block, Is there a best?

Postby sirdeuce » Mon Jun 10, 2019 8:34 am

That wasn't advice from Yoshi, I've done that myself, before Yoshi found out about it. My problem is finding a reliable source for the Aisin gasket. My latest install blocks the oil outlet completely routing the oil out the front of the pump assy. through an inline pressure bypass-filter-cooler back to the block.
One shot, one kill.

User avatar
oldeskewltoy
Club4AG MASTER
Posts: 1898
Joined: Wed Jan 09, 2013 4:44 pm
Location: Portland, Oregon

Re: 7AG Block, Is there a best?

Postby oldeskewltoy » Mon Jun 10, 2019 2:13 pm

sirdeuce wrote:My problem is finding a reliable source for the Aisin gasket.

Toyota for the gasket .....

sirdeuce wrote:My latest install blocks the oil outlet completely routing the oil out the front of the pump assy. through an inline pressure bypass-filter-cooler back to the block.


Interesting.... Photo?
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

sirdeuce
Club4AG Pro
Posts: 661
Joined: Mon Jan 14, 2013 9:47 pm
Location: Sierra Nevada foothills

Re: 7AG Block, Is there a best?

Postby sirdeuce » Mon Jun 10, 2019 3:51 pm

The gaskets Toyota gets me have the round hole. The guys here can't seem to find the one I need.
One shot, one kill.

User avatar
oldeskewltoy
Club4AG MASTER
Posts: 1898
Joined: Wed Jan 09, 2013 4:44 pm
Location: Portland, Oregon

Re: 7AG Block, Is there a best?

Postby oldeskewltoy » Mon Jun 10, 2019 4:54 pm

sirdeuce wrote:The gaskets Toyota gets me have the round hole. The guys here can't seem to find the one I need.


What have you been ordering? 15197-16030? That is 4AGE. 7A would be 15197-16010

Odd... client has a new Toyota Blacktop oil pump, and it came with the elongated feed hole gasket...

Image
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

sirdeuce
Club4AG Pro
Posts: 661
Joined: Mon Jan 14, 2013 9:47 pm
Location: Sierra Nevada foothills

Re: 7AG Block, Is there a best?

Postby sirdeuce » Mon Jun 10, 2019 6:29 pm

Then I have no idea what the dealer is doing, but the hole was round, on four occasions. They didn't just keep giving me the same gasket, I still have them all.
One shot, one kill.

sirdeuce
Club4AG Pro
Posts: 661
Joined: Mon Jan 14, 2013 9:47 pm
Location: Sierra Nevada foothills

Re: 7AG Block, Is there a best?

Postby sirdeuce » Mon Jun 10, 2019 6:36 pm

As for pics of the oil routing I barely described, I never documented that set-up, figured no one would be interested. But if you can imagine, I drilled and tapped the hole for a screwed plug and gutted the pressure relief, installed a male flare fitting. Just bypassed the pressure galley in the block that goes to the filter.
One shot, one kill.

User avatar
Jester_Borris
Posts: 8
Joined: Fri Jan 11, 2013 10:20 pm

Re: 7AG Block, Is there a best?

Postby Jester_Borris » Tue Jun 11, 2019 6:18 pm

That pump mod sounds really interesting. Also, the gasket pic is super helpful. Thanks OST.
1986 AE86 - 20V Silvertop 4A-GE w/ Blacktop ECU

User avatar
Rogue-AE95
Club4AG Expert
Posts: 452
Joined: Thu Jan 10, 2013 4:03 pm
Location: Tampa Bay, FL

Re: 7AG Block, Is there a best?

Postby Rogue-AE95 » Thu Jun 13, 2019 5:53 pm

About the 7A blocks, I swear I saw that there were two different blocks. There is one with less support material near the bottom. I'll dig through my pics and see what I find.

Edit: I found the pics I had. Apologies to whoever they belong to as I have no idea anymore. Unfortunately I don't have any further info on years or models or markets (US, JP, EU, AU, etc) that may contribute to these two 7A blocks being different.

I'm 99% sure both are 7A because:
• Knock sensor provision tapped at top of block (I know 2nd gen 4A-FE also has that, but those blocks are 7 rib)
• Bottom left edge of block in pics has cut-out present on the 7A blocks (and 20v oil pans, 2nd gen 4A-FE, and AE95 All-Trac 4A-FE blocks...)
• Whenever I originally saved these files, I named them with 7A because I was looking through sites for 7A-GE info ;)

Image

Note the long reinforcement running the length of the block near the bottom edge. The exhaust side also has that.

My 1994 7A-FE block is like the lower one in the pic above. In fact most pics of the 7A block that I've seen look like the lower one, with that long reinforcement strip. Maybe the version in the upper pic was the earliest, then it was changed? Or the opposite, a very late change to save on material? Or as I mentioned above, market, car model, etc could be a factor.
'88 Corolla All-Trac

User avatar
Jester_Borris
Posts: 8
Joined: Fri Jan 11, 2013 10:20 pm

Re: 7AG Block, Is there a best?

Postby Jester_Borris » Thu Jun 13, 2019 7:39 pm

That is a pretty significant difference between the two. They look otherwise functionally the same.
1986 AE86 - 20V Silvertop 4A-GE w/ Blacktop ECU

matt dunn
Club4AG Regular
Posts: 34
Joined: Fri Jan 11, 2013 10:40 pm

Re: 7AG Block, Is there a best?

Postby matt dunn » Tue Aug 20, 2019 4:19 am

I have been through a few 7A blocks,
never found one with oil squirters,
and never found any differences in the blocks,
just the extra's, as some had a dist and some were wasted spark and has a CAS built into the oil pump housing.

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.



Return to “TECH: 4A-GE ENGINE”

Who is online

Users browsing this forum: No registered users and 2 guests