Am about to go and speak to an engineers tomorrow about getting the cylinder head reconditioned (89 8v pb engine). I have obtained a newman fast road cam and some new stem oil seals. Am definitely getting it skimmed, valve seats relapped, seals put in cam bearings replaced. what work/ components should i definitely be doing/changing? and what extra work should i be thinking about. the most i want to go to is a stage 1/pack A (whatever you want to refer to it as) head, ie not big valves, and cost is an issue. also, when vw sell replacement camshafts they are undersized and supplied with bearing seats that sit in the head, as opposed to running directly on the head. is this correct or a i mad? and do i need these? i am aiming to go armed with some info so i dont get the wrong work done or not enough work and get fleeced in the process, so any opinions will me most appreciated.
If you're doing all that, make sure they replace the valve guides too. Otherwise you may end up with your new valve stem seals lasting about 2k before they start to leak again. Should only add 50 to the cost of the job, maybe less if you are getting a lot of other work done at the same time. You can't replace the cam bearings, they are part of the head. The VW ones are as you say undersized and you need to get the existing bearing surfaces bored out slightly and the recesses machined to accept standard type cam bearings - not worth it IMO, the std. bearing surfaces are normally totally fine up to mega mileage unless you can see otherwise (any deep scores, etc?, any history of loss of oil pressure?)
valve guides i was defo gonna do, i was more undecided about whether i should be replacing followers and springs. cam bearings i am almost certain are ok from what you say, never had any loss of oil pressure but havent even had to change the rocker cover gasket in 4 years so dont know what the overall condition of the head is! (oil has been changed every 3000 for the last 30000 tho ). what do you think about the benefits of gas flowing, as opposed to just a normal de-coke and clean up?
Followers will be fine unless they are tapping - easy to replace if they do start to tap soon afterwards. I'd leave the springs myself, others would say to replace them. Up to you. A normal decoke and clean up gets you no more power and is cheap, a proper gas flow job costs you big money but will get you more power! Up to your budget, really.... IF it where me (which it quite obviously isn't), I would go for valve guides, recut the valve seats (needed after the new guides anyway) stem seals etc. I'd leave the cam bearings, tappets and valve springs as they are. And as I said, the decoke or full flow job is dictated by your wallet!
cheers for the quick reply as usual SC. i think i know what im gonna do now. the followers have tapped at start up most of the time since i got the car in jan 2000. hasn't really got any worse, although it is worse just after an oil change and seems to get better as the oil gunks up a bit, or maybe my engine is getting louder and i cant hear them as much! i dunno, maybe i should just change em anyway. i think so. will i not get more power with the fast road cam, or is that dependant on gas flowing? i know my standard exhaust wont help but a ss jetex is calling me. im just waiting for the standard pipe to fall off and ive been wating for 4 years. dam vw and their reliablility! i will ask how much the gas flow is and decide at the time, i was more concerned about what HAS to be done and you have answered my question... thanx. i was thinking about hacksawing halfway through my exhaust rubbers to speed up the exhaust change issue! any ideas on that one?
You'll get more power with the cam, but more still with the gas flowing. But a Newman cam is cheap as chips, and a gasflow job isn't! Those standard exhausts last far too long... I can only suggest you remove one of them altogether - it'll bust the remaining ones much quicker......
The gasflow will work better with a decent cam/exhaust & vise versa!! If you are fitting a hotter cam in a skimmed head its also worth thinking about a vernier pulley to correct the valve timing, as skimming makes the cam pulley effectively sit closer to the crank pulley & will retard the cam timing slightly!
hmmm, is that essential? i thought skimming was a standard process that would be carried out on a standard engine if the need arose? also, i am a little confused by the terminology..... is 'porting and polishing' the same as 'gas flowing'. from what i understand from my motorbike days there is a sort of order that mods are done in, as in you dont need a less restrictive exhaust until you are tryng to flow more gas (petrol/air) through the engine, ie you dont really get the full benefits of either exhaust or head work until you fit both.
If you're just skimming to clean up the mating surface, then no need for a vernier. If you're doing it to increase compression ratio for more power (a deeper cut) then a vernier would be a nice addition, but not totally essential.
Skimming is normally done as part of a Gas Flow, & TSC is right, you only really need a vernier if the skim is deeper... My personal experience with F/R cams has shown that out of 4 fitted, only 1 was correctly timed on neutral cam timing. The others were significantly out & required the vernier.. [:^(] My head has been skimmed, but I only have a C.R of 10-10.5:1 so nothing drastic.. I personally think that cam manufacturers delibrately grind the cams in such a way as to make a vernier necessary....Its an extra 80 odd in their coffers at the end of the day!
well, originally, i was skimming coz the head gasket had failed twice now and i dont think it was done before. but now it has to go off to the engineer anyway, and the cam was available cheap, so it sort of developed from there. i spoke to the engineer yesterday who is going to do the work and he said he can up the compression, and something about a different profile on the valve seat and the valve itself. he seemed to know what he was talking about and came highly recommended so im sort of taking his advice, but i explained that im not doing the work to go after big power, more like its a convinient oppurtunity while its all apart to extract a bit more power, within reasonable cost and maintaining all round driveabilty. as far as the cam goes, im gonna give it to the engineer and if he says it has any defects or has been machined out of time, the manufacturer is less than a mile from the machine shop so ill go and have a quiet word! they are made from a mould though, so if ones out they all are!
You wont be able to tell if the cam timing is out til its all back together with the cam belt correctly tensioned etc... With the engine set to #1 TDC on compression (using the flywheel notch) the valves on #4 should have equal ift on overlap for neutral cam timing. i.e the lobes will be facing downwards & each valve should be open by the same amount.. This can be checked roughly, bye eye! You will be able to see if it is significantly out!
sorry mate, dont quite understand that, am i stoopid! probably. you mean number 4 cylinder will have exhaust valve fully open, when number 1 is at the top of its compression stroke and about to go bang?
Yeah both the cam lobes (inlet/exhaust) of #1 will be facing upwards with #1 at Top Dead Centre on compression ..i.e both valves closed Meanwhile, if the cam timing is spot on, both the lobes on #4 (inlet/exhaust) will both be facing downwards& both the hyd. lifters should be depressed by an equal amount. Hope this is more easy to understand!
ok, that makes sense. i was reading part of a book (watercooled volkswagon by greg raven) last night about camshaft duration, overlap etc. and hadnt realised that the intake port opens long before the exhaust port closes! shock horror. surely if the lifters are not depressed by the same amount then there is something seriously wrong with the camshaft? anyway, time to get out to the garage and skin my knuckles. cheers for help
errr, how do the injectors and the injector rail come off. i have disconnected all connectors, hoses, and removed 2 allen bolts on the top and 1 on the left hand side. the rail and injectors seem loose, but im not sure how hard to pull or whether to pull atall..... haynes is typically vague! off the point a bit, but im amazed my car still ran so well considering the number of split hoses i have found. whats the horizontal hose coming out of the right had end of the inlet manifold do? i tried to follow the tbe but it dissappeared
okayyyy... add to list along with various other hoses, cv boots etc i have noticed knackered. gave everything a good check before the winter. shows what 3 months of careful driving can do, lol. anywayyyy... on top of the inlet manifold, right hand side, at the back near the bulkhead there is a hose coming off. let me look in manual to describe this better..... oh, its called vacuum hose to brake servo unit! that explains the spongeness even after new disks, goodridge lines, fluid change and pagid pads! which i was coming to. while im waiting for the head to be done, how is easy is changing master cylinder/servo unit for a 16v unit, and when i go to breakers to find one, what should i be looking for in terms of getting a good one, i mean is there anyway of testing whether its fudged or not off the car. now seems like a good time to get to the servo and its an upgrade ive been thinking about for a while. btw, i did remove the metal clips from the injectors before you ask!!!!! hehe
Buy a new one from GSF/ECP, they are cheapo. Trade them off agfainst each other - I got my 16v MC for 14 last time by blatantly lying.....
