I have been told by a friend (who isn't completely bananas..!)
That I can put a GTS crank and pistons in a 5l block.
That with only minor modifications to the block to make the rods fit.
Is this possible..?

 

you need GTS rods as well, i believe they are different lengths

 

a gts engine is a standard S4 engine stroked to increase its displacement....so yes you can take a GTS crank, rod and pistons and put it in an S4 engine to gain displacement...don't forget that the cams are different too....however with the price of GTS cranks-rods-pistons being SO high....might was well get a true stroker crank-rod pistons & even if you keep the stock bore you'll have 6.0L vs 5.4

 

I was always conflicted on what to do with an early GTS that needs new Rods anyway, do you buy the factory porsche rods, or do you get custom rods which would be even stronger and then buy custom pistons as well? I think the GTS cranks great but the rods are suspect, but of course if your doing rods, may as well bore it out and get 20 years further developed pistons to go with it, likely much lighter too

whats the cost for boring and nikasiling now? Cant that all be done for about $1,000 now days?

 

Hi,
And thanks for all the feedback!
Well I have a complete GTS engine with R2 rods.
Pistons and rods look good.
I have sent the crank for inspection to company in Sweden.
Hopefully it should be good.
So I need not buy anything.
The GTS block is very elliptical, thus I am hoping to use my GT block.
Is it possible to use the GT cams, or must I use the GTS cams and tops?
Cheers.

 

How much was the crank, rods, rings and pistons?

 

The GTS block vs. S4 does have some mods, mostly reinforcements. It is stronger at some points. Even if it is possible, cuz the parameters are equal, I wouldn't like to go that way...

We shortly rebuilt my friends engine - with forged Mahle pistons, Pankl rods everything well balanced together with the crank, 968 valves, polished intake, customized GT-cams, compression ratio at 11.5 and so on and he reached 439 hp on the dyno.

Cheers

Marc

 

The GTS and GT rods are the same length, just different weight. The weight may be a problem at higher rpms, so I wouldn't run GT cast rods with a GTS crank. Given the cost of building an engine, one might want to get aftermarket rods designed and manufactured more recently, anyway.

I think (but do not know) that the "reinforcements" in the GTS block are to compensate for the weakening created by the bored air passages. The air passages fall in the category "benefit not demonstrated." I personally would have no problem using a GT block for any purpose that a GTS block can be used.

Caveat lector as always. Erkka (nic Vilhuer) would actually know.

 

considering that the HP curve will be such that shifting would be just fine at 6000rpm, the stock stuff would work fine. are you sure the GT and GTS rods are the same? so, i guess you would need some kind of custom piston to make work, right, or does a 968 piston have the right offset to work with the GTS / GT rod length?
I think the best bang for the buck is to just use the 968 pistons and do a simple bore job on the block and a used devek crank and the appropriate rods.

However, nicasil is sure working well for me, with the short block Todd built for me.

 

GTS moving parts can be put inside practically any 5L block without any modifications to block. There are cuts made to lower part of GTS block for rod nut clearance but they don't seem to be needed. Nuts get really close but should not contact block. In any case those cuts can be easily made to any block. There isn't anything preventing using earlier block other than making sure bore size is correct for pistons.

GTS rods are and have to be lighter than all 5L rods. Its obviously possible to balance GTS crank to work with heavier rods than stock but it quickly gets so expensive its better to use enough light aftermarket rods instead of GT or any other earlier factory rods. With GTS crank options are ...2R later factory or aftermarket sets. No point in trying to get earlier factory stuff to work.

 

My intention is to use the GTS crank, rods (R2 type) and pistons in a M28-47 block.
Will a GT top fit onto this? Or should I use the GTS tops with GT cams?
My GTS engine is luckily not the 1st generation.
Cheers and thanks..!

 

All '87-95 heads are direct bolt on as are '87-95 cams. Just need correct lenght head bolts which in your case should be same longer type. Cams will fit right in. Its also possible to mix them if needed.

Other than rod nut clearance its direct swap as long as piston diameter fit to block.

 

And btw...
I love the idea of stroking it and using 968 pistons and valves, but I don't have the money for it now.
Just bought a Strosek Ultra..!
I think a GTS-GT engine might do fine for now.
Maybe with a NOS kit to boot.

 

With the GT cams and GTS rotating assembly, my amateur guess is that you'll make good power, especially if you put in a bigger exhaust.

 

GTS rotating assembly, 968 intake valves and ported heads, MSDS headers and X-over = 400+ hp. Even 5L should be very close to 400.