[Shayne18]

What up! This is my first topic I have started on here because normaly I can find all the info I need in previous posts. Any way I have a 92 Sierra with the standard 1.3l in it. I bought it with tyres a bit bigger then stock but fuck all and it would do 110km but took a bit of patience gettin it there. Now I have put 30" bighorns on it so obviously it made it even slower and 5th wasn't an option. So I did some research and ordered 4.16:1 reduction gears from lowrange off road which said would give you that 5th gear back. Sadly that failed and now it's at it's slowest. So I'm now thinkin my donk is tired and I should throw a 1.6 vit in it but surely there is 1.3l sierras gettin at Least 100km in 5th. Also i know my speedo is way out so I used a gps. Any ideas would be sweet!

Cheers...

[Bugsta]

The 4.16:1 surely refers to LOW range, and you re having issues with High range. So what was the original High and the new High ratios?

[ellis]

carby may need a rebuild

[CairnsZook]

Bugsta wrote:

The 4.16:1 surely refers to LOW range, and you re having issues with High range. So what was the original High and the new High ratios?

Sierra 4.16 gears lower both high and low range.
They are perfect for correcting 29" tyres. They should be "ok" for 30's, but not ideal.

If it's now "even slower", then it's not because of the gears. It should be better than it was.

[alien]

definitely start with a carby rebuild... if you can afford it, take it to a shop who can test the thing (including compression) at the same time and make sure its spot on.

my 1.3 with 215/75r15 had no trouble doing well over 120km/hr... 30" tyres and 4.16 gearing is about right, so while it'd still struggle up hills cos of wind and tyre resistance, doing 100km/hr in 5th shouldnt be that bad... but like i said, given a slight uphill you'd still want to grab 4th cos of the other factors.

[Bugsta]

Yeah I would have thoughgt so (me not being familiar with Sierra gearing options), but thinking we should eliminate that as the cause.

[suzooky87]

if ur looking to get rid of the case with the 4.16 gears in it i would be interested............ just say'n

[Shayne18]

Righto cheers everyone I sold my old zook to my best mate and that used to fly along compared to mine any way I will bolt his on coz he has no license and c how that goes. Money ain't a big issue but I work in the mines so the closest carby joint would be about 600km away and I use it as a work bus. So I will c how a carby swap goes and let u know how it goes.

[Damo]

Yes rebuilding the carby will do a lot if the engine is rooted

First thing I would be doing is a compression test.

[christover1]

If its carby, it may be caused by dirty fuel system,
which can quickly stuff up new carby.
Best to clean fuel tank, lines and change filters before giving it another carby.
Also when fuel pump gets old, it can drop bits of diaphragm into carb,
so an extra filter between pump and carby is wise.

Assuming it is a carby problem.

[FullyZooked]

A compression test is far simpler and will actually give you a gauge as to how your engines health is. Compression will tell you if she's tired(low reading dry, high reading wet) if the valves need adjusting and even a burnt unsealing valve.

Smacking another carb on is simply a stab in the dark and may turn out to be a waste of time. If you don't have a compression tester or access to one via mechanic sure, swap Carbs and see what happens. This method of problem finding is by far the most aggrivating and time consuming.

[abclarke]

Mine doesnt go much faster than 110kph. Maybe 120 but thats a 4000RPM+.

Stop being a hoon

[Brett]

Because its a sierra. end of story

do a good service on it

[Shayne18]

Yer I guess I better just rip into it can get hold of a compression tester quite easy. It's just odd that once she's in 4wd I can't fault it revs high as I let go and power seems fine it's just lackin top end heaps bad in 2wd before reduction gears I could do 110km in 4th doin about 4000rpm I ran that for ages and finaly thought I try givin it a rest wit gears but now 4th won't even rev that high now so I have gone backwards lol

[Shayne18]

If any one is still interested compression test came back all sweet. Did all the basics: points, spark, leads, timing, and adjusted the valves and it's still slow as fuck maybe 95km. Is it worth gettin the carby looked out or am I just goin to have to bare the slug. I originaly wanted to take it fishing but I live about 600km from a decent fishing beach that's the only reason I want a bit more sting. Any suggestions would be appreciated!

[christover1]

A blocked or dented exhaust can rob power.

[shiv]

i did a bit of a birthday on mine and it now is able to run in 5th (running 32") can only get to 3k revs in 5th on the flat (no speedo lol) so im guessing thats about 100km

im new to the whole car thing and tuned the carby my self so i know its running rich but once its set up properly and for 98 fuel. i think ill be quite happy with it

[steak_knife]

Damo wrote:

Yes rebuilding the carby will do a lot if the engine is rooted

First thing I would be doing is a compression test.

x2...

Also what psi are you running in your tyre's???

[Shayne18]

Cheers everyone yer my exhaust is unbolted after the first muffler so it shouldn't be to restricted. Tyre pressure is around 22psi give or take 4psi either way on the road. Done a compression test man, dry was 200psi on all 4 so didn't bother doin a wet test as from what I have read anything under 180psi is a bit low. Just an enquiry how much would a fairly big alloy bullbar affect it's speed?

[christover1]

When you say first muffler, do you mean the CAT?
A CAT can block up and cause big problems.

[Shayne18]

Yer it's looks like a cat but I thought efi engines only ran cats

[christover1]

Shayne18 wrote:

Yer it's looks like a cat but I thought efi engines only ran cats

Later model Sierras had CATs but I don't know from what year.

Best get advice from someone with more knowledge on that.

[steak_knife]

christover1 wrote:

Shayne18 wrote:

Yer it's looks like a cat but I thought efi engines only ran cats

Later model Sierras had CATs but I don't know from what year.

Best get advice from someone with more knowledge on that.

Unbolt it!!!!

[christover1]

I searched. Sierras have CATs after 86.

My Cat dislodged and jammed sideways in the pipe.

I tested theory by bashing out the buggered insides.

If You do that, don't breathe the nasty dust.
Try to keep it off ya hands.

And of course replace CAT ASAP

[Shayne18]

Haha I should be a fully sick commy driver and just bash the baffles out. Yer fuck I will rip of tomoro had a look at the bolts then, looks like a hammer and chisel job on those bolts or an oxy! For some reason I'm thinkin that's wat it is just a hunch anyway

[christover1]

I had to soak the bolts in wd40 for 2 days before my bolts would come off.
Somewhere on AZ there was a few ideas on removing stuck bolts

[SierraDan]

I used a spanner and a hammer. Shock gets bolts undone

[ZookFan]

Damo wrote:

Yes rebuilding the carby will do a lot if the engine is rooted

First thing I would be doing is a compression test.

Really what like??

[jdk81]

ZookFan wrote:

Damo wrote:

Yes rebuilding the carby will do a lot if the engine is rooted

First thing I would be doing is a compression test.

Really what like??

I see your sarcasm detector is working well

[Bombero]

Check the butterfly in the carb fully opens with your foot flat to the floor. Sometimes is a prob