ALFAGTV6.COM

[Dbeeson]

This one is for the 24V guys. I've got the GTA 2 Cams in my 24V, but they aren't shimmed.
I assume that this means my intake valves do not open as much as they should be opening, leading to some power being sapped.
Can anyone tell me how much the valves need to be shimmed? Or if it's not a given number, how I can measure how much they need to be shimmed? Also where do I get these shims from, in Canada/USA?

Thanks,

Don.

[Duk]

This one is for the 24V guys. I've got the GTA 2 Cams in my 24V, but they aren't shimmed.
I assume that this means my intake valves do not open as much as they should be opening, leading to some power being sapped.
Can anyone tell me how much the valves need to be shimmed? Or if it's not a given number, how I can measure how much they need to be shimmed? Also where do I get these shims from, in Canada/USA?

Thanks,

Don.

If the engine is sounding a bit rattly (short of some other problem) then the clearances are to great. If the clearances are to tight, then the valve will be riding and be slightly off their seats when they are suppose to be closed (Once up to temperature).
Riding exhaust valves = overheated exhaust valves = stuffed exhaust valves.
Riding inlet valves = slightly less performance but probably no real chance of damage.
Excess clearance = tapping noice = lobe damage over long periods.

You need to measure and record all of your valve clearances on a stone cold engine.
Cam lobes must be directly opposite the valve bucket/follower to make sure it isn't at any lift at all.
Sorry I can't help with clearance but http://www.international-auto.com/index ... 1&addcar=1 can help with individual shims

[TRC Magazine]

24v engine = hydraulic followers

12v = solid followers with shims

[Zamani]

Are you running stock hydraulics or switched over to solids? I'm assuming hydraulic tappets, unless you're running some crazy high lift cams. I think you have to take out the tappets and collapse the inside of it so that it can automatically re-adjust to the new cam profile (added lift? and different base circle). Best if you spoke to someone who has done this conversion. I doubt many (if any) mechanic in the US would know too much about this.

[kevin]

You have three options. Check my post on 3.7 where I used shims on top of valve under hydraulic lifter. This is the easiest option depending if you can get shims made for you. I worked out the cut and got the info on what a hydraulic lifter functions between and made shims. Once you put it in you still need to depress cam follower for gap BUT the hydraulic lifter must be fully colapsed and all oil and air out. If no clearence cut shim but generally all identicall. I cant remember shim size BUT I did get them all recut on exhaust. I have now clocked up 5000km on 3.7 and its still perfect.
Next option is to lenghten valves and there is only one man who can do this successfully here in SA . take head off and numbered each valve before lenghtend . Valve lenghtened the same diff as cam cut . No problems iether there as my race motor is strong as ever.
Third option is solid lifters like on Glenwoods race cars and GTA. Cant help there as no experience .
Which motor have you got GTA or 164 based. These GTA 2 cams are seriously strong as I am getting about 14kw more than the 3.2 147 gta on my 3.0 but I am running after market Gotech management.

[Zamani]

Kevin,

Why do you have to shim the cams? Aren't they hard welded? That would mean the base circle should be the same as the stock GTA cam right?

[kevin]

No these are recut . Some old pics of collapsing lifter and shims from my 3.7. You would not do this if you were a works production team as you would have full solids . But hey they are searching for milliseconds.

[kevin]

You can see the shim on top of valve. Here is a pic of shim.

[Zamani]

Kevin,

how much power do you think you are running with these cams? I'm looking for ideas, may go custom, but the compression will be around 11:1.

Thanks,

Zamani

[kevin]

As mentioned my 3.0 runs 14kw more than 3.2 gta but you have to compare apples as 147 had standard ecu and airbox. I got identical power to an E36 m3 on same dyno. These were intakes only. I had both intakes and exh cut on 3.7 and clearly its not working as it is making great power but way off those other 3.7's with just intake cut. Anyway to lazy to chainge the exh on 3.7 as its such a strong daily cruiser. Zamani these are just my observations on 3.7 and can be totally different to others. From all the dynoing with all the cars the big easy power is in the induction side mainly aftrer the TB. Thats for another thread. Some one proffesional needs to test all this . I know glenwood has the best set up but they will charge for that info .

[Dbeeson]

Well this thread got a bit of action!

Kevin, thanks for the insight. If/when I do this I'll likely do what you did with your 3.7. I had also gone and found those picture last night. Are the shims kind of a cup shape? That's how I'm seeing it when the one is sitting on top of the valve. But in your hand they don't look that way.

When I installed the cams I serviced all of my lifters. My hand ached for a week after that one.

Zamani, what brings about the need to shim the valve for the cam is due to the GTA 2's having a far larger duration, but they don't have as much lift as stock. This is the way I am understanding it so far.

As to engine noises, the engine is a bit rough at the idle when cold, but when warm she doesn't make too much noise.

[kevin]

Shims are cup shape. There are a few of shaps who make shims here. True , your hand will ache for atleast a week.