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5/6/7m block differences?

6.2K views 23 replies 13 participants last post by  supra_toy  
#1 · (Edited)
I was thinking about it t work last night, and started wondering what (if?) differences there are in the m series blocks. (I'm talking about unbolting/screwing/etc everything remotely possible, the bare peice of metal)

This is what I know/think I remember reading:

5m:
82-83, same
84, had un tapped area for knock sensor. And something changed with the bearings.
85-86 added knock sensor.

6m:
clearances for rods cast in
knock sensor?

7mge:
maybe dual knock sensor?
more rod clearance (similar to 6m i'm assuming)?

7mgte:
oil squirters.
88? started using true 7m crank instead of 6m (not sure if there was any block changes) possibly change to different freeze plug and knock sensor configuration?
turbo oil ports
holes for mkiii engine mounts
?more accessory hole clearance? <- unsure of meaning? They can be retapped bigger? or...?




It was just a random thought that if one were to have a variety of blocks lying around, would there be any advantages or disadvantages to using a 7mgte block for the oil squirters on a 5m-ish rebuild?

Edit: sorted through, added the relavent info to my list. (Yes, I can't think of how to spell.)
 
#2 ·
6M blocks have clearances cast into the block for the rods and thats about the only difference. 7MGTE have also the oiling ports for the turbos cast in. There are also two different 7MGTE blocks early and late.
 
#5 ·
MkIIdrifter said:
late 89 the crank changed to fully counter balanced, and redline droped to something like 6250rpm. I think...
Mid 1990 models seems to be the concesus on supra forums.

Obviously the 7mgte block has holes in it for the oil lines on the turbo. 7M blocks have extra holes for the mk3 engine mounts, and they also have 2 holes in completely different spots for the knock sensors (pretty sure the 7mge has 2 as well).

If you have any other questions nows the time as I have 3 7mgte blocks spread out over my shop floor and a complete 5m in the corner and my buddys 7mge down the road on an engine stand.
 
#7 ·
i have a late 89 7mgte, its the 6m crank. i got a 91 7mgte and it has the 7m crank. my 87 and 88 7mgte's both had 6m cranks as well. also, the 91 block felt heavier then the 88 block, but i havent had time to compare side by side yet to see if there is any extra ribs or anything in it or weight them. i have both blocks completely bare. so will wiegh them when i get a chance.
 
#8 ·
The later 7m blocks have different freeze plug and knock sensor configurations and around the oil pump mounting flange is a little different for the crank throws. The rest of it looks pretty much the same IIRC.
 
#10 ·
Phil G. said:
Curious.... thought the 6M and 7M cranks were nearly identical but not. Could I possibly be wrong???

<-----------------Mr. Technical Guy
I belive the 6m cranks only had counterweights on every other rod journal, and the 7ms had counterweights for all rod journals.
 
#12 ·
I believe the 82 and 85 oil pumps where different as well. I am actually going to try and check on this as I don't remember for sure. I had to use the 5mge oil pump put of my friends 82 along with the pickup on his 6mge. But I don't remeber having to do that with mine I thought all I used was the pickup tube and not the pump I thought I threw that away.
 
#13 ·
85 oil pump and pan are deeper then the 82. i think 82-83 got the same pan/pump and 84+ got the deeper units.
 
#18 ·
the 7mgte and 6m cranks are the same specs, so are the rods techniclly, though the 7mgte rods are a lil beefier. and lil devil. the reason you need the 85 pump and pan is cause the 85 pump has the exact same gears internally as the 7mgte pump so has identical flow. the 82 pump and i believer the 83 and early 84 had shorter pumps, and shorter gears so didnt flow as much volume. also, i may get a chance to examine the 89 and 91 blocks side by side wed. if i see anything diff ill take some pics of it. as it is i need to find someone to come get the junk 5m block out of my storage unit so ill have more room.
 
#20 ·
yeah, it does, take apart a ge pump and a gte pump, and the gears inside the gte pump are taller. and the 85 5m pump has the exact same taller gears as the gte. shawn has confirmed this with side by side comparos.
 
#21 ·
7M-GE's have 1 knock sensor, 7M-GTE's have 2 knock sensors.

The 7M-GE and 7M-GTE had the 6M crank up until 1989, 1990+ models got the newer fully-counter balanced crank. The 6M crank doesn't have counter balances on the number 2 and number 5 cylinders.

The fully counter balanced crank is 5lbs heavier than the 6M crank.

7M-GTE block is tapped for the turbo oil lines, and the oil squirters. The 7M-GTE also has the higher flow oil pump over the 7M-GE (was already mentioned).

I've never heard of the knock sensor arrangement or freeze plugs ever changing on the 7M.
 
#24 ·
good stuff

will