504 engine rebuild options?

[Pug72]

Hi all

I would to rebuild the engine in my 504.

My plan is to buy another block and build it up then transfer into car so there is minimal down time (as my 504 is my daily driver)

I have been searching the internet lately, but still would welcome any advice please.

This is where I am at:

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1. Block - do I go 504, 505 or 505 STI/GTI?
2. Head - square port that will be ported and polished
3. Inlet - custom manifold with twin Weber side draft (something I have always wanted)
4. Exhaust - custom extractors, 50 or 65mm system

I will be retaining the original 3 speed auto.

So I am after any thoughts here please, and if you have a block, square port head or inlet manifold (to suit the Weber) that you are willing to sell, please let me know.

Thanks heaps

[addo]

I am curious as to why you might retain the current auto box - rather than fit something newer with four speeds and possibly a locking converter.

[GRAHAM WALLIS]

At least fit a ZF, unless it is an early car which already has it.
No point in using a square port head if you want to fit Webers, you need a Ti or 505 SLi head.

I am curious as to why you might retain the current auto box - rather than fit something newer with four speeds and possibly a locking converter.

[Pug72]

It's a 1972 with the ZF 3HP20 Auto. Only recently had it rebuilt. Its a very smooth gearbox!

Ok thanks Graham, will try to source a 504 TI or 505 SLI head

[lionheart]

There is a fellow in W.A. advertising on Gumtree complete 504 Ti motors. Freight to Brisbane may not be too prohibitive - I had a complete motor & gearbox sent from Perth to Brisbane on a pallet for $150.00.

[ThanosK]

For a daily driver I would stay away from sidedrafts, they are extremely thirsty. I believe that converting to a Ti is the best option, IF you can find a complete system (fuel tank, return lines, rear fuel pump). If not, a Ti engine with EFI is a good option, you will need to fabricate a return line and add an inlet to your fuel tank. Talk to Graham about the EFI conversion. If KF injection or EFI are too complicated, a Ti engine with a 1 mm head skim, an Argentinean intake manifold, a downdraft progressive Weber like a DGAV (or Aussie equivalent) a warm cam like the Wade 112, will be a very nice and not too expensive upgrade from your current engine.

[addo]

Thanos - are you including CD type carburetion in that dismissal of side-draughts on a Pug motor, or just Weber/Dellorto?

[ThanosK]

Thanos - are you including CD type carburetion in that dismissal of side-draughts on a Pug motor, or just Weber/Dellorto?

My experience is only with Webers and XN2 race engines. My wife's 72 Beetle has twin Dellortos and a warm 1.7 engine with a Porsche cam and it is quite economical as a daily driver. But one of our friends has the same car with Megasquirt and it is faster and smoother, with better throttle response and more economical.

[Beano]

Jeez....it's difficult to answer a completely open-ended question.

It all depends on you. I've seen your car at Bastille Day and it looks quite original.....and you seem quite proud of it's originality. Are you sure you want to change that ? And another setup (like a GTI engine in there) will require a lot of periphal bits and bobs attached to it.

Down time for an engine rebuild can be not long at all, if you have the parts ready. Why not just rebuild the one you have ? It's got fairly low Ks, hasn't it ? The only real downtime will be the time the cylinder head is getting done in the machine shop. Two days, perhaps.

Having said that, 505 blocks (and cylinder heads) have a higher cooling system pressure rating (the welsh plugs, that is). 504s only have a 4lb radiator cap.

If you don't want to do up your original engine, the most basic setup would be a 505 GR or SR block and square port head, with a Renault Fuego Weber. No fiddling around with jets...just bolt on and go. I've never much liked Webers off Falcons....I've never been able to achieve linear acceleration with em.

I'm too busy to do it for you, but I have previously rebuilt many 504s and 505s. If your engine has fairly low Ks (under 250 k), it's fairly standard procedure to not have to regrind the crank, or replace the little end (gudgeon). They are seriously strong engines !

For the first rebuild (at less than 250 k) I used to regularly replace the rings and big end bearings only ! As did the local engine reconditioner. NOT the main bearings ! This of course was subject to inspection of all components and varied slightly....sometimes.

I used to use the original pistons and cylinders....but I would get the pistons machined to accept Volvo or Toyota rings, which are wider and non-chrome......(chrome rings are soft, which some people like and others don't). I'd interchange number 4 and number 1 cylinder, and also numbers 2 and 3, so that what had been the thrust face was now at the back, and what had been the rear face (and therefore unworn) was now at the front.
In my own 505 I got ten years and 200k after doing this, and it was still going well after I sold it at well over 400,000Ks.

Whatever you end up doing, if you do use a cast iron block, I have one suggestion, which I would recommend VERY STRONGLY : While it's apart, have someone professional install a helicoil into one of the cylinder hear bolt holes in the block. It's the one at the rear on the exhaust side.
In both 504s and 505s, the thread in this particular hole becomes degraded with heat and age, and will sometimes seem ok .....until you tighten down the bolt. But then you'll have to take off the head, get another gasket etc etc. And it's awkward to helicoil with engine in.
It's because the back of the engine gets hotter and it's on the exhaust side.
Do the one in front of that if you like, but definitely do that one. It's not expensive and it'll be money well spent.....trust me.

[leftcoast]

And what would one do to the std xn1 TI motor internals in order to run minor boost, apart from the usual, would you rebuild with different parts or would a std rebuild be able to take it? Like valves/seat liners/Pistons ..... You all knew the question was coming. Haha

Beano, all your advice is greatly noted, cheers

[robmac]

And what would one do to the std xn1 TI motor internals in order to run minor boost, apart from the usual, would you rebuild with different parts or would a std rebuild be able to take it? Like valves/seat liners/Pistons ..... You all knew the question was coming. Haha

Beano, all your advice is greatly noted, cheers

I'd fit hard seats (if not already fitted) and bronze guides to the exhaust valves, and also have the crank, rods, flywheel , clutch pressure plate balanced. PP can be a long way out of balance.

When the liners are out clean out the block with a small wire brush in a drill to remove all traces of rust inside the water jacket.
Flush the oil galleries in the block with a de-greaser and a pressure pump.
Remove the brass plugs from the crank and clean out the oil galleries with a small bottle brush.

Assemble the liner & seals with light smear of Wurth DP 300 high temperature silicon sealant on the block face. Clamp the liners immediately after.

I recommend having the stripped engine & head components hot bathed. Head castings are normally cleaned in a special aluminium cleaning bath.

If the cam followers are pitted, they can be refaced, likewise the rocker gear can be reground if there is bad wear.

Check the cam lobes for wear. Replace the timing chain tensioner (and chain if stretched).

Assemble the engine with lots of oil.

Have the radiator "rodded" by a professional radiator company.

And check the condition of the oil pump.

[Peter C]

It's amazing how much gunk builds up behind those brass crankshaft plugs.

[Pug72]

Thanks everyone for the replies and advice. I would love to do this myself, but just don't have time. I have many ideas running through my head and Beano, you are right re keeping the originality of the engine bay is something that is at the forefront of my thoughts.

The reason I started this thread is that I have noticed one of the rear welsh plugs starting to weep coolant. The engine was first rebuilt in the mid eighties and that was only due to the liner seals letting go. The engine runs very smooth and does not burn any oil or consume water (apart from the weeping welsh plug). I do know that there is sludge in the coolant galleries of the block as I had the radiator rebuilt 12 months ago and the bottom tank was full of sludge, even thought the coolant has been change regularly.

Also when I changed the water pump last year, looking inside the head did not look good re corrosion (welsh plug was dislodged - I fixed this)

The starter motor, and all electrics are under 12 months old.

I will start to buy a few things like gaskets etc now and talk to a few people that I have in mind to rebuild the engine.

Thanks

[Peter C]

If the main problem is a leaking welsh plug why not just replace them including the big ones at the back of the head? It's not really a fun job removing the engine just to do that but it is cheap. This would give you time to obtain another engine and build it up for when the time comes down the track.

[Pug72]

If the head is coming off, I would prefer to getting the block out as well. The block really needs to be cleaned out. While it is out, the rear main seal can be done.

[robmac]

It's amazing how much gunk builds up behind those brass crankshaft plugs.

It certainly is:

[Peter C]

Yes, it frightened the life out me the time I removed them.

[robmac]

Yes, it frightened the life out me the time I removed them.

The crank was jammed full of grey granules and needed to cleaned out with a battery drill and wire brush.

Amazingly the journals recovered with a linish.

[Peter C]

And it's amazing that all the crud stays put and doesn't damage bearing surfaces.

[robmac]

And it's amazing that all the crud stays put and doesn't damage bearing surfaces.

The crud is soft, but lack of oil, caused by blockage was my concern.

Turbulent and laminar flow principles, the crud falls out when the oil velocity changes.

[Demannu]

If you're not worried about originality, my vote would be on a 505 GTi motor. Cheap, reliable, economical and torquey. Stick a Fuego Weber carb with an adaptor plate on it if you want to keep it simple.

I suspect you could use a 505 3HP22 bellhousing on your 3HP20 also. Otherwise, just put a 3HP22 in it. Or a 5 speed manual.

All a bolt-in proposition.

[robmac]

If you're not worried about originality, my vote would be on a 505 GTi motor. Cheap, reliable, economical and torquey. Stick a Fuego Weber carb with an adaptor plate on it if you want to keep it simple.

I suspect you could use a 505 3HP22 bellhousing on your 3HP20 also. Otherwise, just put a 3HP22 in it. Or a 5 speed manual.

All a bolt-in proposition.

If you can live with 100 % LPG, then I'd think a gas carby, or simple ring mixer on the GTI manifold would be a good option.

and a simple conversion.

[Demannu]

If you can live with 100 % LPG, then I'd think a gas carby, or simple ring mixer on the GTI manifold would be a good option.

Agreed, I had a 505 with a ZDJ engine running on straight gas, and they love it. Though it does add some complexity to the conversion.

[Mike Tippett]

...but if originality goes as far as wanting matching numbers on the block and manufacturer's plate, there is only one choice! it's got to be getting into a time when it's appreciating somewhat.

[BIGRR]

Could it really be that hard to fit a new welch plug in the back of the head with the motor in situ? There must be a good 110mm to work in between the end of the head and the firewall!
Considering on the 15th May 2015 "Quote" "Car runs like a dream."?

Good Luck.