PDA

View Full Version : Smallport 16V 4AGE Head Questions



HILTZ
19th March 2013, 11:59 PM
Hey Guys,
I've got a couple questions regarding a smallport 16v complete cylinder head that i've been given by a friend.
A little bit of background info on the head and my car,
Engine was a 4age 16v smallport from an ae93 gti.
The engine was swapped due to a cracked block, my friend claims the new motor never went as well as the old one.
He seems to think the old motor may of had aftermarket/larger cams fitted due the way it rev'd/went after 3000 rpm.
I have an early 4age 16v bigport 16v in my ae71.

Question 1: Is there anyway visually or measuring to comfirm if the cams have been changed ?

Question 2: If the cams have been changed is it possible for them to be fitted into an early 4age 16v bigport head ?

Question 3: Will you need to swap all the shims and bucks over aswell ?

I know that you can fit bigport cams into a smallport head, but i couldn't find any info if you could do the opposite.
I'm guessing that you could do it.
Thanks Hayden.

Hen may possibly be a nut
20th March 2013, 07:17 AM
1: Get a set of calipers and measure. Across the smallest part of the lobe gives you the base circle. From the tip of the lobe to the far side gives you the max height. The difference between these two is lift. There may also be markings on the cams you can Google.
2: Yes.
3: Once the new cams are fitted check your valve clearance and adjust to suit. If you have two sets of shims you'll probably find you can swap them around to make it work, but in any case you can't avoid measuring.

4: Yes, you can swap the entire smallport head onto your bigport for even more sikness.

HILTZ
20th March 2013, 09:21 PM
Thanks hen for your reply, very helpful info.

willa
21st March 2013, 05:57 AM
4: Yes, you can swap the entire smallport head onto your bigport for even more sikness.

Well, you can't. You can swap the internals over, but the actual head itself is different, so if you put the the small port head on your inlet manifold will not fit!

Will

Hen may possibly be a nut
21st March 2013, 10:14 PM
Well, you can.

True, it's not plug and play, but you sure can bolt a smallport head on. Intake adaptor or cut'n'shut smallport intake required, also smallport fuel rail, plus other odds and ends. No big deal.

Futo_gt86
25th March 2013, 10:23 PM
Off topic but is the Smallport GZE and NA fuel rail one and the same?

Hen may possibly be a nut
26th March 2013, 03:26 AM
I think they are the same, but if not they are interchangeable. I've used a smallport GZE fuel rail on an smallport NA manifold.

Futo_gt86
26th March 2013, 08:31 AM
I think they are the same, but if not they are interchangeable. I've used a smallport GZE fuel rail on an smallport NA manifold.

Exactly what I'm about to attempt.
Thanks Hen.