Brilliant little project! Hows the Vtec coming along (im sure it was you who posted it on PF?)
Of course!
Just got my hands on some new alloys, and d2500 pads.
I have only just checked the dates, I finish college on that Friday, so need to work out how to get from Plymouth to Bedford, and get hold of my wheels, and see about swapping them over, without being to tired for some full on driving
Nice work guys
Supertech uprated valves being lapped in by the mrs to the freshly prepped head:
Hands going so quick the camera on my iPhone couldnt keep up, lol
In work we use cordless drills for that
Yes it will mean I need to run 0.1 psi more boost or whatever to get the same power, so no drama to me but it shows why its so worth doing on an N/A one of these engines if you are trying to tune it.Surely that roughness is going to reduce/interrupt airflow to an extent? Worth cleaning up or not much of a difference?
To save me clogging up Dan's project thread ill reply here.
There is a rather large difference in size on them! My car has had the head ported on it by 519 when he owned it, on N/a im sure it makes a larger difference. You not doing anything with the 197 head?
Not doing anything at all with it mate, I cant already get more power than I want so there just isnt any point in me porting the head, this is only a quick rebuild with some forged bits to make it stronger, Im not looking for one single extra BHP that I didnt have originally.
Although that said I have just bought some 197 cams to make it hold on just a tiny bit better at the top end, but thats just basically to regain a little that I will lose from slightly lower compression ratio this time round.
Be careful with who you get to port heads, Neil Roper is the business, ex F1 including doing heads for Ayrton Senna no less, some random backstreet mechanic having a quick go with a die grinder doesnt always actually make things better, and its not as simple as bigger is better, very subtle shape changes in the ports are where the real gains are, more so than the change in finish even though thats much more obvious to look at it.
I have ported heads in the past and got reasonable gains out of it, but Im actually aware that Neil can do a better job than I can and because through some of the people I work alongside we get a lot of heads done by him I ended up getting good enough prices that it really does make it not worth spending so much time just to do the job not quite as well myself, so if I was going to do anything with it then it would be to send it to him.
So Chip if I'm reading this right you can put the 197 head and inlet stright onto a 172 bottom end and due to the size of the ports enabling the engine to breath better will see power gains (although small if staying NA). What sort of gains would you see with cams on it? Any idea?
So Chip if I'm reading this right you can put the 197 head and inlet stright onto a 172 bottom end and due to the size of the ports enabling the engine to breath better will see power gains (although small if staying NA). What sort of gains would you see with cams on it? Any idea?
You need to drill and tap the 197 head for the cambelt idler roller as well. The 197 doesn't have this.
MWM must have already done that on mine, so I wasnt aware of that, thanks for the info