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[stedee]

hi all
i have got a 33 p4 with a slipped cambelt , i presumed the valves were bent because the engine was making a loud tapping noise.
so basically out came the engine and i have took the heads off, i was expecting to see something obviously wrong but this is not the case.
my questions are can a slightly bent valve cause this type of loud ticking?
and how can itell if i have bent valves - i was going to take the valves out anyway and roll them on a table to check for this.
also i was going to get the heads skimmed (for a bit more power)but there doesnt seem like much clearance, does the stepped piston give the allowed clearance because i have heard you can get the heads skimmed quite alot.i have read on the internet that the comprssion should be 10 - 1
but because of factory tolerances it is more likely to be 9.5 - 1, i wanted to skim my heads so they were about 10.5 - 1 as the limit is meant to be 11 - 1 due to the octane of petrol or something like that anyway
cheers for any advice steve
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[markgp4]

Hello Ste,

i just rebuilt one for the same reason, it had slipped a belt but it wasnt really noisey.
only way i found which valve was bent was to turn the valve train ( usin a spanner) when the head was off the engine -its not easy- but its the only way i know to check it other than stripping every valve out of the head.
Cos despite being fairly bent it wasnt obvious til it was "open"
i did strip the valves out in the end and spent hours grinding them all in. and had the heads skimmed just to be sure evrything was right before i put it all back together....

Am well pleased with the result tho.
God luck with it
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[stedee]

cheers for the reply
but i have done that already and i still cant see which one(s) are bent, what do you look for ?a delay in opening or closing or look at what you can see of the shaft, either way i cannot see anything obviously bent.
i am a bit worried now that it is something else but what?
i definately know the belt had slipped checked the belts myself and the engine does make a loud tapping noise, i found a few things out though when i checked the engine though eg. 2 of the injectors are not working properly, one of the throttle body gaskets as got a tare and there does seem to be alot of brown gunk in the oil filler ( i know 33s are prone to getting this oil/water emulsion at the filler nozzle) but there is a lot of it
any advice appreciated.
ps is your car faster now you have skimmed the head , how much did you have took off. i am going to port the heads myself and do a little mod i have seen on the alfaboxertuning website with the inlet valves plus skim the heads and if i have got any spare cash i was going to get the flywheel lightenned.
steve
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[markgp4]

mine showed on the shaft when valve was open fully ...

could the noise be a hydraulic tappet maybe damaged one of those instead of bending a valve? (only guessing here)

~As for the rest of your questions, i ground the valves in, polished the insides of the throttle bodies as its all rough metal in there made em smoooth ...
i had low comp on rear cylinder thats why i had heads done and had both done so as not to be "unbalanced"...but i couldnt tell you how much he took off and hes no longer available to ask im afraid.

BUT i also bought new set of big end bearings, and new rings and honed the bores.
All of this together definately gave me a more free revving engine than before and i do think it pulls harder too than before.
Mark
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make it go faster

[stedee]

i will let you know what`s wrong when i get the heads apart
cheers for your help - steve
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