yep, there are rebuilds, and then there are rebuilds. as said, get exact and complete details in writing, and post them up here for appraisal.
RE: Bronze valve guides ( whats is these for?) Typically, they are used to "guide" the valves, in other words, they are bushes fitted to the Heads, and the Valve Stems pass through them. Stock CR on a TT is 8.5:1.
Just a little more about Cam pulleys I intend to swap mine to a set of Tomei or similar pulleys. I have read that there are big gains on mid range torque to be had by increasing the cam overlap. One article said that adjustable pulleys can give you 70% of the improvement of a hotter cam grind. Doesnt actually sound too preposterious seeing after a grind you cannot adjust it again so how do you ever know its optimized. Comments anyone?? Also, who is experienced enough to adjust these pulleys on a dyno after fitting ?
If the stock pistons have a CR of 8.5:1 whats the point of buying a stillen set? And is the 8.5:1 better then the 9:1? im a little confused sowwii.
That 70% improvement......>> Was that on a TT zed? By fitting adjustable gears you will lose the VVT setup so you will need to work out if the gains in the midrange are worth the losses in the bottom and top ranges. This has been discussed before but there is no hard data on the subject. No one that I'm aware of who has fitted them has done any back-to-back testing with the gears as the only mod.
Re: That 70% improvement......>> Why would it stuff up the VVT Peter? Are you sure? I am gonna have to check this again tomorrow. One of the pulleys is only a bolt on pulley with a single bolt holding it on. The other has a VVT pin that goes into the centre of the gear, with a spring and other crap in there. I actually didnt have a good look at it while I was pulling apart the parts engine. But I cant see how making it adjustable would stuff up the VVT. Better check into this. The article was written about an RB25.
I believe that the best results......>> Are obtained by fitting the gears to the inlet camshafts and then tuning them, rather then fitting them to the exhaust gears (no idea why). The factory VVT system works by oil being pumped into the existing gears on the inlet cams causing them to turn in relation to the shafts. If you remove the factory gears to install the adjustable gears you will lose that function.
exhaust cam gears get the main gains I think so its easy to just fit adjustables to these. Keep the VVT on the intake.
Re: exhaust cam gears get the main gains I think Mmm, I was having a look on UAS's site today and they have adjustable gears that look like they have been made from normal ones. (they ask for the old ones in changover) The centres are machined off and an adjustable alloy ring bolted between the inner spokes and the outer ring. The outer ring has adjustment slots machined into it so you can shift the cog relative to the centre. I think this could be done on the inlet pulley as well. In fact I recon I could even make them. I may have to look into this seeing I have a spare set of all the gears.
I think you might be wrong.....>> About it being doable to the inlets. But I'll let you knock yourself out experimenting.
So no adjustable pullies>? is better - true or false? Also is a compression rate of 9:1 better then 8.5:1 I dont understand this concept sorry can some please explain.. thank you :thumbsup:
Well aK I think adjustable pulleys are an advantage if you know how to use them on a Dyno. Increasing the overlap can give startling gains in mid range torque. I dont think the compression ratio being 8.5:1 or 9:1 is all that relavant actually. The lower ratio would let you run a bit more boost, but that is off set by less compression therefore less inherant power anyway. Its a tradeoff. I would be more interested in a discussion about the best brand of forged pistons rather than their compression ratio. Arias, Repco etc which one is best and why ? Also what rings to use on them ? Also discussions about Stroker crank shafts. I dont remember having seen much about them anywhere. If I was going to buy a new high tech crank I would want the cash spent on a bit more stroke to get the capacity up, and therefore a bit more torque. What do you guys who have had engine rebuilds know about stroker conversions? Did you look into it?
I don't have any valid reason to think that 9:1 is better than 8.5:1, but.. I certainly don't find it to be any worse either. I don't believe there is sufficient difference to make a value judgement. Just my opinion. As for "stroker crankshafts", the VG crank is such a strong item, I wouldn't swap it for an unknown item unless there was some really convincing arguements to support doing so.
News flash guys The VVTi pulleys are already adjustable as standard. Check this out ! Looks like the exhaust one is the only one you need to buy. I tell you what though, There is no easy way to adjust these from the front. To make them truly adjustable they need to be modified so you have access to the bolt heads from the front of the pulley.
but does that have still have the VVT stuff inside the pulley or is it an intake pulley from a US Spec Zed which had the VVT removed (1995+ I think).
This looking on the inside of a standard TT VVT pulley This is the engine I bought to do the TT to NA transplant. Its from a Jspec zed. The VVT stuff was all in place when I removed it. I would think that these are standard. It is a bit surprizing if yours wasnt like that Chewy, and even the CAM gear on my NA has the same pulley with the same screws in the same place. The VVT soleniods where all in place on this engine so its not a 95 model that had it removed. I will jump ahead here and say they all have it. Normally this is the side of the pulley that faces the rear of the engine and you cant see these bolts unless you take the pulley off. All you can see is the threaded ends of the screws around the pulley face. But they are there. :thumbsup: I think I may mod this spare pulley so you can adjust it from the front. I will take a pic of the front tomorrow so you guys know where to look.
both of my engines didn't have that setup. All up there are 3 different intake pulleys. One from 7/89 till 6/93, 6/93 till 7/95 and then 7/95 onwards. I assume both of mine are from the 7/89 to 6/93 batch since both engine numbers place them at 1989 and 1990 each. I would suspect the engine you have is one of the other year ranges. The problem you'll have with turning the bolts around in that pulley is that the thread will be on the front side and threading the bolt in will not hold the part with the slots in it unless you use a nut on the backside which defeats the purpose. You might have to come up with a strange looking nut so it jams itself against the out edge of the pulley. I put one of the my pulleys in the drop saw and cut it open to have a look inside and thought it wouldn't be overly difficult to machine an adjustable one up.
