Author Topic: SB to JX differences.. upgrade? (Read 5360 times)

Ghia · « **on:** May 15, 2007, 03:18:37 pm »

I've just stripped down a seized SB code engine which had fractured it's turbo return pipe!

The head however is ok along with cam, injectors and pump.

My T3 Bluestar runs a JX (plod-along!) motor.

I have read somewhere here that the injectors are an upgrade from the SB and that the pump is better for tuning.

What about the cylinder head and cam? The JX has solid tappets but the GTD has hydraulic tappets. The cam part numbers are different but I think that's prob to do with the solid/hydraulic part.
Are the valves different sizes?

Is it worth pulling the head off and doing the swap?

Thanks in advance.
Mike

RabbitJockey · « **Reply #1 on:** May 15, 2007, 05:39:02 pm »

the heads won't swap and its not an upgrade either way, but assuming the spray and break pressure of the sb injectors are ok, then they are an upgrade. depending on what injector pump you already have, the sb one could be an upgrade, but not a performance one... but it really depends on what condition the stuff is in.

rod1e · « **Reply #2 on:** May 16, 2007, 12:33:48 am »

I'm putting an SB into my '87 syncro and I busted one of the pistons...
Can't find one 'round here so do you want to sell or swap one??

It's marked;

+++
76V54
A101

MAHLE
A1
DE

76.48mmm (standard)
068AT(?)

A couple of things...
Have you thought about changin the pump levers?? I've been told that the pump will catch the engine cover with the original levers. ('cept maybe on a syncro 'cos the engine is slung a bit lower) The old levers off the JX pump will not reach the stops and there is no block for the spring... the new spring won't hook onto the old lever.

What turbo do you have? on the old JX I've got a K14 and on the SB a Garett T2... it needs a bit of coaxing to fit and keep the water cooling but it seems to fit...

Ghia · « **Reply #3 on:** May 16, 2007, 10:32:03 am »

The heads won't swap? why?

I plan on running the stock JX turbo as the GTD can be a bit laggy for a van. I remember running a Golf GTD and nothing happened at all below 2,500 rpm...

I plan to do a compression check on the JX to see just how worn it is and then decide whether to put the bits on the JX or build a GTD engine and do a swap.

I'll have a look at the pistons for the markings though.

MG

Ghia · « **Reply #4 on:** May 16, 2007, 02:13:05 pm »

Update,

Having measured the valves, I can say that they are the same size for SB and JX so no performance upgrade there.

If the head won't fit then I'm either look for another bottom end or selling the head.

MG

RabbitJockey · « **Reply #5 on:** May 16, 2007, 03:18:53 pm »

one is a solid lifter engine and one is a hydraulic lifter engine, so they won't swap directly, i mean they can but it'd be pointless since there is no performance upgrade since they are more less the same head.

rod1e · « **Reply #6 on:** May 17, 2007, 12:36:33 am »

Thought there were extra oil ways for the Hydr.Head??

I would rebuild.. ('cos that is what I am doing) Then you get a spare TD to play with.... If you are thinking of taking the head off etc... (I presume the van is no spring chicken...) You should do a load of other stuff while you are in there... 'cos you will have to eventually...

I think it's easier to drop the engine and trans and do the head on the ground. (Bottle jack, tree stumps, skateboard, wooden beam and some rope...)

There is only 8kw difference between the SB and the JX (spec) and I guess most of that's 'cos the GTD had an intercooler??

Thanks for looking at the pistons but I need them sooner rather than later so if it's not all in bits already don't worry about it... thanks...

RabbitJockey · « **Reply #7 on:** May 17, 2007, 04:15:57 am »

the hydro heads have an extra return hole. which really makes no difference in performance or how much oil gets into the head, i don't quite understand why vw did it either, although they did on there gasoline and diesel engines so it makes me curious.