OST-049: 1G-GTE

[oldeskewltoy]

Well, I've worked a 5MG, and 7MGTE, now it's time to work their little brother, a 1G-GTE





The 1G-GTE is a 2 liter inline 6 cylinder that made 210hp. The 1G-GTE uses a 75mm bore, and 75mm stroke, as a comparison, the 4AG uses 81mm bore and 77mm stroke.









Anyone see anything??



more to come.......

[oldeskewltoy]

Anyone see anything??

Did you see what the arrows were pointing at? Originally I was worried... that discolor, and shape are common when looking at burnt valves......... but they cleaned up



Valve sizes: 28mm intake, 23.5mm exhaust. As comparison, the 4AGE uses 30.5mm intake valves, and 25.5mm exhaust valves. Very cute... the 1G-GTE intake valves have both the Yamaha logo, and the "teq" logo, while the exhaust valves just have the "teq" logo.


The head is now back from the shop, it's clean, and pressure checks ok.





One more step before I begin work...... a new tool




A new flowbench bore adapter... This one 77mm



more to come......

[oldeskewltoy]

got it on the bench......





more to come.......

[oldeskewltoy]

progress(left chamber).......... bowls and seats now @ 85% of valve diameter




more to come....

[oldeskewltoy]

got the head back from the machine shop...

3 down.... 3 to go





more to come.....

[oldeskewltoy]

Before.... and after - intake side.



The 1G-GTE uses valves that are about 5mm shorter then 4AG valves... yet the 1G-GTE valve guides are HUGE in comparison. The 1G guides measure out to 45.75mm(1.8"), the 4AG guides 40.65mm(1.6"). so the valve is 5mm shorter, and yet the guide is 5mm longer - so I shortened the guides.




more to come........

[oldeskewltoy]

Before.... and after - intake side.



The 1G-GTE uses valves that are about 5mm shorter then 4AG valves... yet the 1G-GTE valve guides are HUGE in comparison. The 1G guides measure out to 45.75mm(1.8"), the 4AG guides 40.65mm(1.6"). so the valve is 5mm shorter, and yet the guide is 5mm longer - so I shortened the guides.




more to come........

This time the exhaust side.......




more to come....

[oldeskewltoy]

and to try to explain the exhaust ports...... (the odd shape inside...)




more to come.....

[oldeskewltoy]

I had the stock cams "mapped" by Web camshaft....



What do they tell you??




more to come......

[oldeskewltoy]

I had the stock cams "mapped" by Web camshaft....



What do they tell you??




more to come......

Well.... let me tell you what I see.

1) split durations - exhaust longer - LIKELY to compensate for added valve clearance on exhaust side - but not limited to that reason

2) Beginning with the intake cam, the overall duration is 261, while duration @ .050" is 194, the exhaust cam is 270/199. As a comparison - stock early 4AG cams are 240 overall, and 204 @ .050". Observation - The 1G-GTE cams have a VERY mild/gradual ramp.


Now to fit that in with what I found on the flowbench. The stock intake ports began to go flat @ .250" lift, and went total flat by .300". The stock exhaust ports went totally flat by .250" lift.



The newly ported head changes the heads flow. Now the intake port flows out to .350" lift, while the exhaust port now flows out to .325" before going flat. With the head changes, a new set of cams are being built for this 1G-GTE.......





more to come.....

[Davegt27]

interesting
never seen a head mapped out like that
I picked up a new project and started researching it and found some info from a DTM race motor

you have to click on the racing engine to get info on the 1990's straight six DTM engine and go down and see what they did to the head
https://translate.googleusercontent.com ... rp8KJMl9PQ

[oldeskewltoy]

interesting
never seen a head mapped out like that
I picked up a new project and started researching it and found some info from a DTM race motor

you have to click on the racing engine to get info on the 1990's straight six DTM engine and go down and see what they did to the head
https://translate.googleusercontent.com ... rp8KJMl9PQ

took a look @ your link.... I found what they did to the chambers interesting....




back to the 1G......... the cams finally came - the coating on the lobes is to aide in break in






Went through and checked clearances...



shims on order.....


more to come.........

[oldeskewltoy]

clearances set!






Now that the clearances are set, this head gets shipped back to its owner....