3SGE shims - tolerable minimums?

[thechuckster]

I'm working on the head on my RA65's new budget motor and have come across a challenge. After re-doing the valve seats and re-assembling the valve train I've ended up with a whole swag of just-under-minimum cam-to-shim gaps.

I've ended up with:

• Exhaust (specs are 0.2-0.3mm)
• Valve - gap - shim thickness
• #1 - 0.18 - 2.9
• #2 - 0.18 - 2.9
• #3 - 0.31 - 2.8
• #4 - 0.18 - 2.9
• #5 - 0.18 - 2.9
• #6 - 0.18 - 3.0
• #7 - 0.18 - 2.9
• #8 - 0.06 - 3.1 (not sure why this gap is so small)

• Intake (specs are 0.15-0.25mm)
• Valve - gap - shim thickness
• #1 - 0.15 - 2.9
• #2 - 0.14 - 3.0
• #3 - 0.16 - 2.9
• #4 - 0.15 - 2.9
• #5 - 0.18 - 2.95
• #6 - 0.22 - 2.9
• #7 - 0.18 - 2.9
• #8 - 0.10 - 2.9

I'm going to re-check the way-out numbers in cyl #4 and also re-measure the shims with different calipers to get more accurate figures. I can partly address the small gaps by swappng pairs of shims around.

... but I'm just wondering with the gaps so close to the minimum specs, should i:
A - ignore them as an unknown problem is not a problem
B - attack the slightly over-sized shims with wet-n-dry on a sheet of glass
C - defer to the wisdom of the toymods-collective (aka we are toymods, your biological and technological distinctiveness will be added to River's Facebook profile)?

[.T.]

will take forever to sand down shims & then you risk going through the hardening - so don't do it.

either visit wrecking yard & "liberate" a collection of shims from various toyota motors (you will find the thicknesses vary dramatically on different types of toyota motors) or -

get the valve stems nipped - any machine shop should be able to do this for you to open up the clearances. i assume you had the valve seats recut?

[rolleraction]

I'd see how they settle down after you've run the engine for (?) Km's after you put it back together, as they gaps will change again (slightly) if you have reseated the valves. It wont be an issue it you dont rev the tits off it in the interim. Shims used to cost $15 each a few years ago. Also, if its a Gen 1 with 28mm buckets, 4AG are the same as are Yamaha FJ1200 bike shims. The aussie racing car guys all have a bag of these as they have to adjust them all the time due to the constant high revs they run the FJ1200 bike motors to.. If you know anyone running in that series, they may swap your shim for one they dont use/have many of? FWIW. Steve.

[thechuckster]

thanks for advice guys, I might put aside a few hours and go collecting shims from a wrecker or two. Am hoping the 3/5SFE use the same shims as you find a lot of them at wreckers and usually very few GE motors.

From memory, the shims are 25mm OD - but that's a vague recollection. I'll go over on Friday night and re-measure them.

.T.: I just hand-lapped the valves - however, they all got a second pass on the fine paste. Would prefer to leave the valves in the head at the moment but it is an option to have them shortened.

rolleraction: I only mostly know car nerds on here and some rally guys - no Aussie Racer folk. But, the pointer is most helpful and I might ask a motorbike nerd mate of mine about which wreckers up here keep borked motors in stock and allow parts scavenging.

[oldcorollas]

individual shims must be pretty cheap?

did you happen to start on #8 for the lapping?
being at the minimum should be ok. unless your valves get really hot?

[thechuckster]

last time i looked for shims online - when i was building the GT4 motor - they were $8ea (thru http://www.precisionshims.com.au/). Didn't bother with a Toyota price at the time as I was in rural Sunshine Coast and the only useful dealer was in Nambour.

I did start at #8 for lapping - but didn't think I was being that hard on it

Car/motor use will be: daily driver, rural-highway cruising & single-axle-trailer-tug (in that order), so the hardest use will be when I'm running late on a weekend visit to see Lucas and pulling the trailer.

[oldcorollas]

swap the 2.9 from intake #8, with the 2.8 from exhuast #3,, that will give 0.2 and 0.21 respectively (??) ( i know you already figured that )
then you just need a 2.95 for Exhaust#8?

as per .T., sanding = no

valve ends are often hardened but more like 1mm or so, so nipping is ok.

i wouldn't worry about being on the minimum side...
my poor little 4K has 0.05 less than minimum (sure totally different system) and got caned with ne'er an issue..

oh.. are your cam base circles round? ie, does the gap change with position around the base circle?

[thechuckster]

Yup, was going to swap stuff around to get #8 a bit healthier

But would rather not pull valves out if I can help it.

And, for consistency, I measured with the cams lobes opposite the shims. I don't have a magnet-mounted dial gauge so I haven't bother to check the cam base-circle or for that matter the cam journals for being true-centre.

Am a bit annoyed with myself for going gen1 engine. My gen2 GTE motor needs thicker shims and it would have been nice to swap between the two.

[oldcorollas]

i think i just used feeler gauge to measure 3 or 4 points around each base circle.. ie find one that fits, rotate a bit, see if it gets tight or loose...

[3sgte]

Check the inside of the bucket on the tight ones.
I have seen some where the end of the valve stem makes a pit on its contact surface inside the valve lifter.

Also, I'm curious about what vintage this 3S-GE is. There are old and new, the old being a small diameter shim, and new being a large diameter shim.
The small shims occasionally fail, they wear in a concave shape where the cam lobe presses on them. I would not consider sanding/lapping.

[thechuckster]

It's a gen1 3SGE. AFAIK, all of this vintage (it came out of an ST162) are the smaller diameter shim.

[3sgte]

Yes, small shim = gen 1.

The 3SG with the small shim are the ones that I have seen with a bad (worn) shim.

[thechuckster]

will go thru the ABC yard at blacksoil today and look for shims. Will take calipers with me and snaffle anything 2.9mm or smaller and not obviously rooted. While there will see if there's an opened 5SFE or V6 Camry and measure up the shims (for the GTE motor).

[oldeskewltoy]

pop "25mm shim" into google......

4AG, 4AF use the same 25mm shims too.

[thechuckster]

4afe was today's winner. there were 2 gen1 GE motors but couldn't get the timing belts off (both were hanging on the upper mounts). Found a lid-less 4AFE and saved all but one shim from being recycled. All except one were 2.8 or smaller. They're soaking in wd40 to remove the grime and i'll re-measure them.

Grabbed an AE92 airbox while i was there which looked adequate for the task.