cam question

[donnyavery]

ive been doing some reading (trying to get as much out of my http://www.mr2.com/forums/forced-ind...get-build.html) and i keep coming into info that ses the 4age 16v non tvis motor used different cam lift and duration does and one have any info and would this be and in improvement for the 4az(t)e as ive been seeing thanks for reading my post

[te51levin]

Early ('85-'86) cams are reputed to have a slightly more aggressive profile than later cams. I would stay with those until you get ready to go aftermarket. Later cams will not be an improvement.

[donnyavery]

that the info i was looking for (but i have the later and was thinking of trying to find a early set) what is the diff in lift and duration between tvis and non

[te51levin]

I'm not sure. You can search around for it, which is what I'd be doing. I do not believe that anyone has actually measured these cams properly in quite some time, if ever, so keep in mind it may be little more than stale internet rumor...

The difference in part number is not simply between bigport (TVIS) and smallport (non-TVIS). It is between early ('85-'86) and late ('87+) bigport cams. Smallport cams may have different part numbers too - I don't know, and since I am not at work, I can't find out right now.

[mr2_jake]

Largeport - 240º Duration @ 7.56mm Lift Smallport - 232º @ 7.1mm Lift

I believe this to be accurate. I'm unaware of differences in 85-86 to 87+ cams.

Swapped my smallport cams out for the large port's. Definitely noticed!

[te51levin]

Originally Posted by mr2_jake

Largeport - 240º Duration @ 7.56mm Lift Smallport - 232º @ 7.1mm Lift

These are the figures often quoted, but I have no idea where they came from. I'd love to find out for myself. I'm the kind of person who has to prove things before accepting them - particularly if they come from the internet, or magazines, or even most books anymore.

Originally Posted by mr2_jake

I'm unaware of differences in 85-86 to 87+ cams.

I have confirmed, via the EPC, that '85-'86 cams are different than '87+ cams. There is no difference between '87-'89 bigport cams and smallport cams. They use the same part numbers. If the numbers you quoted are accurate, the "smallport cam" designation really applies to anything built from August 1986 (i.e. the introduction of the 1987 model year) forward.

I know the tone of this probably sounds argumentative, but that's not the intention at all. I just want to make this as clear as possible, that's all.

[mr2_jake]

Hmm. I have no clue to tell the truth, just info I got from old skool toyota guys. Before I swapped the cams in I mic'd the lobes and the large ports were indeed bigger, didn't keep track of numbers tho, just wanted to verify they weren't identical. I have heard the early cams are slightly different than the latter, but I don't know. All I do know is the large port cams I put in were original Toyota, and were definitely more aggressive than the small port's original Toyota cams I pulled out.

[te51levin]

Sooner or later, when I have lots of free time and hundreds of thousands of dollars for R&D, I'd love to measure all the cams out and see how they really compare. Better buy a few lottery tickets this week...

[jimmer411]

Side by side there is definately a difference in lobes between the late/smallport and early cams. I question the lift tho, with a caliper both cams measured the same tho its possible that the bluetop cams had worn down some since they came from an engine with 170k miles vs the 50k on my later cams.

[mr2_jake]

.45mm is pretty damn tiny....(if that is the actual lift)

[donnyavery]

what does the # at the and by the cam gears mean i got 2 sets that have 10 on them and 1set that as 9 and another set 12,and the latest set i have are a mismatch one has a 2 and the other 4