Thread: DVE vs VE

If they are truely identical to N1, I will put money on that when you pull the head you will find knick marks from the valves.

well not planning on pulling the head anytime soon, And when i kissed the valves on my sr20ve motor due to mis shifting, the motor lost compression down low occasionally when the valve wouldnt seat right, once the valve would turn a little during operation it would seat. Thing is his has perfect compression and doesnt not run how mine did when i kissed the valves.

when i pulled the head on mine you could see the nick marks on the #4 piston that had contacted the exhaust valves. The intake ones were fine. It was only the exhaust valves that kissed. And when i was loosing that compression down low you could hear the air being shot through the open ssac header. making a nice little hoot sound. so i knew right then what had happened before i even compression tested it.

My buddies car runs great. Thats what got me thinking about the cams also but who knows. I just know what happens when valves kiss the pistons even slightly, it doesnt take much.

A DE bottome end with a VE head does not give 11.7 to 1 compression.

The compression of a DE bottom end with a VE head is about 10.4 to 1 compression.

A standard DE piston and a standard SR20VE piston have about the same dish volume.

If you post a pic of a 20V piston which is 11 to 1 compression it is almost a flat top piston and a flat top 10 to 1 piston is about 11.3 to 1 compression.

I kissed off with SR16VE cam straight up with BC H22 springs on DET pistons.... I still did 230psi across the board. I checked the valves they weren't bent, little lapping and they seated fine again. Just because you hit doesn't mean your motor blows up and stops working.

So you are judging that they are not hitting just because you haven't completely bent the **** out of them to the point that the motor doesn't run? I will get in on that bet if you ever get to pulling the head.....which I have a feeling you will have to do soon. Not to be a dick, but coming from someone who has gone through multiple motors over the past few months including a ve that got it's valves bent, I wouldn't trust you eyeballing valve clearance.

Now I do remember Charles testing the Franklin stage 3's and finding that the centerline was way off on them. So if by some miracle, you have no clearance issues, then I would assume that their incorrect centerline has something to do with it.

again could be, i bent the valves due to having no rev limiter and misshifting, that motor would not have dropped the valve into the piston had i had the rev limiter. I just had not got my new set of chips for the calum ecu yet.

I originally set my tune without the limiter cuz at first i was planning on using n1 cams but plans changed and i wanted to boost the motor so the cams were out. Its bad luck yes but my own stupidity even more. Its not because i dont know what im doing its just that i pushed my luck with it. Same with a couple of other motors. the other stuff was plain bad luck. how often does our hydraulic lifters completly fail causing the rocker to pop off and then get so unlucky it wedges between one valve spring and bends it open and smashed up the motor. Yeah unlucky if you ask me.

Neways back on subject. I know how to time a motor. But your right i cant see the clearances. I knew they would be close hence why im sceptical of even going past what i already have the gears set to, Also even if the centerlines are off by a bit, they still dynoed exactly to the n1's straight up to straight up. So either way.

I also understand that you can kiss the valves just lightly and that wont cause them to bend enough to not seal. The valve does have flex to it and it does take quite a hit to bend them enough to do what it first did to my ve motor. But gain i mis shifted and reved to probably 13k on stock cams and valvetrain for that to happen. I took that motor to 8500 a couple times with no problems. im sure i was getting a bit of valve float but not enough. But this was only on a couple occassions. what ruined the motor was the last and final overrev to probably 14k or who knows what.

Neways we will dyno them and then maybe re dyno with the cams put back at 0,0 to see what happens with the powerband. It it makes more power at 0,0 then thats where they stay and gives me more ease of mind knowing they are safer that way also.

^Wow lol. Possible theory.



^You mean with the 10.1 piston being on a VE head?

Yes a 10 to 1 DE piston with a VE head on top is about 11.3 to 1 compression or so.

sorry that was a typo in my other post about the compression ratio. didnt even see that, haha, yeah i meant to say 10.7:1 or so. Ill correct it in the other post.

WOW thats great news for me!! i think only 93 fuel for that setup.

Andreas i got a 10:1 engine from you, if i get a VVL head for it, there will be any clearence issues???

What if i get the N1 cams too??