24-04-2014, 10:31 AM
(This post was last modified: 24-04-2014, 10:32 AM by powerandtorque.)
At the end of the day, you pays your money and takes your chance.
Certainly I wouldn't be entirely comfortable if it were me running those cams timed up properly on a skimmed by an unknown amount head, especially not knocking on the door of 8k rpm and taking it pretty much unproven over to Germany.
Unskimmed and with the revs below 7500 I'd have reasonable confidence in them being OK.
You should be alright if you're running the cams retarded from Catcams specifications as that will reduce lift @ TDC and thus the chances of the valves and pistons getting intimate, but I would suggest keeping the revs below 7500 as given the clearances you're running any lifter pump up will be terminal. I'm assuming with those cams and a longer inlet that peak power must be lower than that anyway?
The good thing is that you're effectively running a standard engine with some bolt on bits, so worse case is that it's a ~£200 consumable engine and a couple of days to replace it. Bit of a pain if it goes bang in Germany of course...
I'll leave it at this James - all three people I know that have run GTi-6 engine with marginal clearance has at some point down the line suffered a valve related failure. One (Catcam 109's) was on its first trackday after mapping, one (PT81's I think) was about 2-3 months later, and the last (standard cams run advanced) was about a year later, and in each and every case the cam pulleys were still set and the tensioner hadn't slipped.
Perhaps a good (if not particularly valid) comparison would be big turbo'd standard XUD with the fuelling cranked up. It will be fine on its test drive and thus logically it should continue to be fine, but there's a fair chance that it's going to throw a rod at some point - be it a week, a month, or a year.
On the subject of tensioners btw, you are running the earlier 136 tooth belt and eccentric tensioner setup aren't you, rather than the later 137 tooth belt and auto-tensioner? The later really doesn't deal with bigger cams very well and the belt tension tends to be all over the place.
Certainly I wouldn't be entirely comfortable if it were me running those cams timed up properly on a skimmed by an unknown amount head, especially not knocking on the door of 8k rpm and taking it pretty much unproven over to Germany.
Unskimmed and with the revs below 7500 I'd have reasonable confidence in them being OK.
You should be alright if you're running the cams retarded from Catcams specifications as that will reduce lift @ TDC and thus the chances of the valves and pistons getting intimate, but I would suggest keeping the revs below 7500 as given the clearances you're running any lifter pump up will be terminal. I'm assuming with those cams and a longer inlet that peak power must be lower than that anyway?
The good thing is that you're effectively running a standard engine with some bolt on bits, so worse case is that it's a ~£200 consumable engine and a couple of days to replace it. Bit of a pain if it goes bang in Germany of course...
I'll leave it at this James - all three people I know that have run GTi-6 engine with marginal clearance has at some point down the line suffered a valve related failure. One (Catcam 109's) was on its first trackday after mapping, one (PT81's I think) was about 2-3 months later, and the last (standard cams run advanced) was about a year later, and in each and every case the cam pulleys were still set and the tensioner hadn't slipped.
Perhaps a good (if not particularly valid) comparison would be big turbo'd standard XUD with the fuelling cranked up. It will be fine on its test drive and thus logically it should continue to be fine, but there's a fair chance that it's going to throw a rod at some point - be it a week, a month, or a year.
On the subject of tensioners btw, you are running the earlier 136 tooth belt and eccentric tensioner setup aren't you, rather than the later 137 tooth belt and auto-tensioner? The later really doesn't deal with bigger cams very well and the belt tension tends to be all over the place.
1990 Peugeot 205 GTi 1.9 // 1991 Peugeot 205 GTi 1.9 16v // 1992 Peugeot 205 GTi 1.9 // 1999 Peugeot 306 HDi Estate