GU rd28t. where is TDC? WILL A GQ HEAD WORK

[mr green]

hi all, fist time outside the suzuki section so try and be polite.
bought myself a Gu wagon a few months ago but its a 2.8 i love the car itself. it very quiet and comfortable but its a slug on and off road. i have done a lot of reading up on the 2.8 and the general consensus is that they have little torque but a slip of the clutch and it should go.
problem with mine is, its not a little slip of the clutch, its a rev to 2+ grand and release. anything below that and its a 4 or 5 second wait for power, which is not that great when trying to sneak into a break in traffic. off road is a similar story. lines that my old 2.8 lux would craw, the patrol either boggs down so much it won't move or its a masssive slip of the clutch to keep it around 4 grand. far from safe when trying to negotiate the rough stuff. and don't even ask how much abuse is reqired to do any sort of a hill start with a 8x5 box trailer loaded with firewood.
i bought this car at auction so i didn't have the chance to drive it and i have never driven another 2.8t patrol to compare it to. what i have noticed is the amount of smoke mine blows compared to every other Gu on the road.
to me it seems like a timing problem. it had had a timing belt, possibly kit, fitted 40,000kms ago. i have rechecked the timing belt by lining up the top marks (pump and cam) and counting the teeth for the crank. all good. but what i did notice was the keyway on the crank was not at 6 o'cloch like my timing book showed it should be. it was more like 7 o'cloch but a tooth the other way brings it to around 5:30.... if you know what i mean.
i'm wondering if the wrong sized idler had been fitted throwing the marks out. the only way i can think of checking it would be to take the sump off to see exactly where TDC is. but if someone else has set up the timing on a few 2,8s and can confirm or clarify where the key should point at tdc that would be tops.
thanks for any help, jason

[GU BOOST]

If u wont abit more power they go alright with a full 3 inch exhaust and a chip. But as for the timing yeah dont no. Good luck buddy

[Clanky]

Looks to me like the keyway is perpendicular according to the diagram. NOTE that the diagram below doesnt account for the slight vertical angle the engine is installed at

You sure you have the right T-belt in? There are two types, one with rounded teeth and one with squared teeth.

That said I tried fiddling a fair bit to get some decent bottom end in the 2.8 without huge success. Most of the timing and pump fiddling just made it use more fuel.
Intercooler and exhaust make a bit of difference, + a bit of tuning. But if you look at the torque curves for the engine even if you double the low down power at say 1000rpm its still not a big number.

And they do have a 'dirty' exhaust when off boost. Must be something to do with engine design and low speed cylinder scavenging. Cleans up on full boost though

Best thing I did was put a set of crawler gears in the t-case, and became a master at changing from low to high and vice versa on the move.

[BadMav]

You might have a stuck wastegate? Even check the actuator is not holding it open.

[mr green]

thanks clanky for the diagram. that was just what i was after. my key is more advanced than that even taking into account the angle of the motor. ill check the belt for round or square teeth but i didn't notice anything wrong and it must be the belt designed for that motor cause its got the lines to match up with the gears. i am thinking i might have to order a genuine ider pully and see if its bigger than the one fitted.
checked the wast gate, all good there. the problem is pre boost, when boost comes on i don't have too much to complain about. my real concern is if i ever have to put a big trailer on it (car trailer or caravan) could get hairy. unlike the old 2.8 lux, where i knew it would do everything i asked of it , but might be slow,, the trol would be a case of "will it do it at all". i will get a bit excited if i find out the idler is the wrong size

[mr green]

Best thing I did was put a set of crawler gears in the t-case, and became a master at changing from low to high and vice versa on the move.

havn't tried shifting on the fly.... that might be the next trick....... how do the auto hubs like the bitumen?

[Clanky]

Best thing I did was put a set of crawler gears in the t-case, and became a master at changing from low to high and vice versa on the move.

havn't tried shifting on the fly.... that might be the next trick....... how do the auto hubs like the bitumen?

Get some manual hubs. I have used my low range in 2wd when I hauled my sons 40 home on a trailer and copped a red light on a nice uphill. With the 83% gears you hit 4th gear get a bit of speed then into neutral, slip it into high range, then pick 2nd and awaaaay you go. No clutch riding or anything.
PITA yes, but I was like you and bought a 2.8 unawares, and the truck was in top nick.

[Clanky]

thanks clanky for the diagram. that was just what i was after. my key is more advanced than that even taking into account the angle of the motor. ill check the belt for round or square teeth but i didn't notice anything wrong and it must be the belt designed for that motor cause its got the lines to match up with the gears. i am thinking i might have to order a genuine ider pully and see if its bigger than the one fitted.
checked the wast gate, all good there. the problem is pre boost, when boost comes on i don't have too much to complain about. my real concern is if i ever have to put a big trailer on it (car trailer or caravan) could get hairy. unlike the old 2.8 lux, where i knew it would do everything i asked of it , but might be slow,, the trol would be a case of "will it do it at all". i will get a bit excited if i find out the idler is the wrong size

When I set mine I used the belt markings, but also doubled checked by counting the teeth using the numbers on the diagram.
Maybe your belt has the marks in the wrong place? Easy place to start. I had both genuine and aftermarket tensioners and they were exactly the same

My part numbers were

Rounded teeth belt ( many numbers from all the old belts)
Gates T1032
3A03682249
T1032 149 RU30
76149 x 30 HSN

Tensioner NTN JPU-100 +JF526
Idler NTN JPU60 - 362

[mr green]

SO i'm at my wits end with this car. i check and double checked the timing. all ok. thought tight tappets would explain all my symptoms. poor starting ( winds over for about 4 seconds before starting and will not start without glowing regardless of temp) zero torque. have to rev it to 2ooorpm to get the clutch out in first. and clouds of smoke.
so an saturday I thought i would do a valve clearance check. so, off with the tappet cover and found there was no clearance on any valves.. thought this was just what i wanted to see!! BUT there is no shims on top of the cam follower like the manual says there should be. so, out with the cam to have a better look.
the cam follower/ lifter has no recess to hold a shim and no sign there has ever been any. i'm getting very inquisitive now. after trying to work out how the follower works and with no shims and no clearance the only thing i thought i could do was rip the head off to see if the valves are seating.
now this is where it turns into a long story. with the cam back in, 11 valves stay about 1mm off seating over night they all eventually seated. this kinda sucks for me. i now don't know where i'm up to. i don't know if the lifters have a problem and are holding the valves off the seat when oil pressure is met or if i'm at a dead end. what i do think though, is that someone has been to it before me and fitted a gq head (that doesn't take shims and has no clearances)
so, my question is, does anyone know if there are differences between the gq and gu heads that might give valve clearance issues?
please help, or if someone has a wife they want to swap for a gu, pm me..... cause mine has had enough of this!!

[Clanky]

Hehe
I have a wife and it sounds like a fair swap to me

OK, your starting issue could be the injector pump. There was a thread either here or patrol4x4 forum. I will see if I can find it. Its a relatively simple fix.

The heads are the same as far as I know, however dont quote me without checking first. The only difference between GU and GQ was the electronic injection. I Cant help but think you are on the wrong track with the cylinder head.

Let me see what I can find

[Clanky]

http://www.patrol4x4.com/forum/showthread.php?t=9070" onclick="window.open(this.href);return false;

http://www.patrol4x4.com/forum/showthread.php?t=6428" onclick="window.open(this.href);return false;

http://4wdinteractive.com/forum/showthread.php?t=81961" onclick="window.open(this.href);return false;

Hope this gets you going.

[mr green]

thanks for the info clanky, will be good if you can find that thread.
the gu has shim adjustable valves and the gq hydraulic non adjustable lifters from the specs from auto tech. i drove another 2.8 gu last week at work and it was a night and day difference to mine wich is why i'm trying to suss mine out. the good one sounds to have more compression while cranking than mine and with a light on a stick through the oil cap hole i can see it has different cam followers and shims as the manual says it should.... not like mine this "good" Gu that i am refering to is the same as mine in every way 99 modle st wagon. has 250,000kms vs 260,000kms so at the moment it is my bible!

[mr green]

thanks for the links clanky, just been called back to work but will have a good read when i get home.

[Clanky]

Hey your right about the heads. The drawings are identical on both, but the GU has the shim shown which I didnt see first time around.
The shims are quite large (thickness 2-3mm) and its more a 10c piece size. I was expecting something a bit more thin.

Anyway, there is two versions on the engine. The early (GQ) had the vac pump on the rocker cover and the later had it somewhere else. Does yours have the vac pump on the rocker cover? Maybe yours is the last of the hydraulic type.

I wonder if your engine was swapped out of a GQ? The GU's were a bit more powerful. Does the body plate match the engine number?
There is usually a stamping or casting on the head with identifying numbers - if you can locate these you might be able to check with Nissan or on that other GU.

Sorry im not being too specific, just trying to give you ideas

cheers

[mr green]

yep, mine has the vacuum pump on the tappet cover. didn't think to check where it was on the "good" one at work. i'll check the numbers and see if i can find anything. i was thinking the engine would have to be Gu cause it has the crank sensor and tone wheel, not sure that could be fitted to a mechanical injected engine.
i'll have a look through the links now.......... damn i wish i did a compression check before i ripped the head off now, but in the heat of the moment and one thing leads to another....... you know

[Clanky]

Yeah sometimes its hard to pinpoint problems.
And to save stuffing around with measuring up your head gasket, just go the thickest one. I suspect you are going to up the boost anyway