Ok, so not Clio related but you lot are much more knowledgeable than most.
So after the recent Toyota 2ZZ-GE engine swap into my MR2 Roadster with the new (old) 2001 150k mile engine the crossover to lift (VTEC if you will) and 6200rpm onwards is definitely not as strong as it was on the old (newer) 2006 80k mile engine. The 150k mile unit doesn't rev to 8200rpm as the old 80k mile unit did, more like 8000rpm although i'm using the same ECU.
At first I thought that it was just because of the age, mileage and condition difference of the engines but I changed the cams, rockers, rockers shafts from the 80k unit into the 150k head and adjusted the valve clearance to OE spec. I've also done a leakdown test and results came back fine on all cylinders. So this has got me thinking maybe the timing is slightly out?
Here is a picture of how it should be:
Here is how I set mine:
Now I've blown the pictures up and looked at them side by side maybe the exhaust cam is slightly off, more like 3/4 of a tooth instead of 1/2 a tooth. It could just be the camera angle though.
Not sure if 1/4 of a tooth out on the exhaust cam would slightly reduce lift (VTEC) though? If so it means I would need to move the exhaust cam down 1 tooth on the chain but with this the chain/cam marks wouldn't then line up with each other. Could it be a slightly stretched chain maybe? I used the 80k mile chain from the blown engine as the new one I purchased didn't have the correct timing marks so didn't use it.
Or could it just be souly down to the age, mileage and condition of the engine in particular the valves, valves seats, springs etc?
So after the recent Toyota 2ZZ-GE engine swap into my MR2 Roadster with the new (old) 2001 150k mile engine the crossover to lift (VTEC if you will) and 6200rpm onwards is definitely not as strong as it was on the old (newer) 2006 80k mile engine. The 150k mile unit doesn't rev to 8200rpm as the old 80k mile unit did, more like 8000rpm although i'm using the same ECU.
At first I thought that it was just because of the age, mileage and condition difference of the engines but I changed the cams, rockers, rockers shafts from the 80k unit into the 150k head and adjusted the valve clearance to OE spec. I've also done a leakdown test and results came back fine on all cylinders. So this has got me thinking maybe the timing is slightly out?
Here is a picture of how it should be:
Here is how I set mine:
Now I've blown the pictures up and looked at them side by side maybe the exhaust cam is slightly off, more like 3/4 of a tooth instead of 1/2 a tooth. It could just be the camera angle though.
Not sure if 1/4 of a tooth out on the exhaust cam would slightly reduce lift (VTEC) though? If so it means I would need to move the exhaust cam down 1 tooth on the chain but with this the chain/cam marks wouldn't then line up with each other. Could it be a slightly stretched chain maybe? I used the 80k mile chain from the blown engine as the new one I purchased didn't have the correct timing marks so didn't use it.
Or could it just be souly down to the age, mileage and condition of the engine in particular the valves, valves seats, springs etc?
