[engine_work] Twin Weber 1.4 8v Build

[Sandy 191]

I was asked a while back to put together a 1.4 8v for a customer that had collected a range of parts for the job already. The brief was basically what many TU 205 owners work towards, namely a punchy and fun 1360 8 valve on twin carbs. It had to be kept within a reasonable cost, which means choosing where to spend time and hence money, carefully!

 

I was thinking of throughly documenting this build, to perhaps create a sort of guide to building an alloy TU, but it was going to take too long really and most of the process is covered in the Haynes manual, so I'll stick to a casual summary and a few details.

 

John supplied me with his 205 Rallye with a running XS engine on twin carbs, which was staving off corrosion by liberally coating itself in oil, as they do! In the boot was a stripped 106 XSi 1.4, a freshly ported head and some suspension parts to try.

 

Engine bay during strip down:

 

The original plan was to use the XSi pistons in the alloy block. I was put off this approach a bit though, because the XSi pistons are pretty large with short con rods, I prefer using shorter pistons and longer rods as a rule and I had some 1.3 106 Rallye rods/pistons that I could use with a little modification.

Fitted onto the 1360 crank, the 1.3 piston (with 1.3 rod) will rise clear of the block by about 1.5mm plus the intruder. The ideal way to modify the piston is to turn the crown down in the lathe, but to do this, you either need a lathe big enough for the rod to sit inside the spindle or remove the piston from the rod, but being an interference pin, that's a proper ball ache.

The solution was to use an Iron block with a crank solidly mounted in it and mill down the crowns. This turned out to be a pretty laborious process though and I'm not in a hurry to do it again!! I originally planned to have slight protrusion from the block, but it wasn't essential and it proved much easier to machine the crowns flush, which would still mean 11:1 compression with the chamber volume I had, plenty for a distributor ignition engine. I eventually cracked it on the second attempt.

I had to make slight valve cut outs for the inlets in the piston crowns. I did this by turning an old valve into a cutting tool and mounting it in a head with no gasket, so it could be spun with a drill and the cut out would gain clearance on both axis.

 

None of the old liners where good enough to re-use without oversizing, so I had to stretch the budget to new liners. Peugeot don't supply liners separately, so replacement items were used, but the rings are genuine and took about 6 weeks to come from Peugeot! The Rallye top rings are very tight and hard, you have to fit them with extreme care to avoid breakage.

 

The head that John had already was a bit rough ported for my taste, so I set about revising the ports and throats. It was only a quick tidy up, but arguably better than it was. I sourced a Catcam 4900646, which I've had very pleasing results with before and a Catcam adjustable pulley. The standard springs are on the limit really with this cam, so I sourced some springs too, to ensure there would be a positive valve control at high rpm. The head was skimmed down to improve the squish band and get the chamber volume I wanted.

Colin fabricated a new inlet manifold to my design, which I ported to continue the tract shape all the way through.

Bits:

 

Head prior to valve grinding and assembly:

 

Catcam spring (left) vs OE XSi spring:

 

Rings, modified pistons, new liners and big end shells prior to assembly:

 

One of the little annoyances with the TU, is that the OE valve collets butt together, which over time causes the grooves in the valve to distort and could (although I haven't seen it yet on the TU) cause a dropped valve. The way to prevent this problem is firstly to ensure any lips on the grooves on the valve stem are removed (which is sometimes necessary to get the valve out of the guide), and then to grind down each of the collets so there's a small gap when fitted on the valve stem. To do this, judiciously grind the faces of the collets with a Dremel or similar tool in a vice; occasionally offering the collets up to the stem until satisfied. Bear in mind that you're effectively creating matched pairs of collets, so from then on, kep them together.

 

Before:

 

After:

 

When fitting the pistons and liners, "clean" the liner with quality paper towel soaked in oil, until no dirt residue is evident, the fit the piston. Lightly oil the liner seal and slide it gently over the liner, ensuring it doesn't twist as it's fitted. The condition of the liner seats in the block and the liner protrusion is crucial to a good seal, so pay much attention to this when preparing the block.

After a fair bit of huffing and puffing (and ordering the correct big end bearings, I ordered oversize originally by mistake ), the bottom end was together:

 

I don't use a gasket on the sump pan, they always leak profusely on these. I clean the gasket face back to bright metal and seal with stippled Loctite 5699 adhesive sealer.

 

Sump pan:

 

I'll post some more details later.

[stu_woac 1]

I hope your going to sort out his top mount for him too as in that pic It looks like its only bolted mine is fully welded has the bolts just wanted to snap all the time once the grpA engine mount was fitted its now never fail and I'm glad as I didnt want it failing on the Ring when I went (a couple of years ago) must go there again soon going to do spa the same time when I go LOL

[Sandy 191]

Haha, yep, Colin's making a steel one, to solve the problem once and for all If anyone one wants a duplicate mount, let us know while we've got the car here!!

[RossD 44]

Odd that you say the 1.4 XSi pistons are quite large, I've always thought they are massively long compared to the other TU pistons, any idea why that is? Those 1.3 pistons in the pics above look pretty much the same as the 1.6 TU pistons. (I think they share the same rods too.....?)

Edited October 29, 2007 by RossD

[Sandy 191]

Odd that you say the 1.4 XSi pistons are quite large, I've always thought they are massively long compared to the other TU pistons, any idea why that is? Those 1.3 pistons in the pics above look pretty much the same as the 1.6 TU pistons. (I think they share the same rods too.....?)

The 1.3 rods appear to be the same in every way as 1.6 8v TU rods yes. The 1.3 pistons are quite similar now they're machined, but 75mm vs 78.5mm bore obviously. They have less mterial around the pin though.

 

I'll put an XSi piston next to a base model one later.

[Sandy 191]

An update.

 

First up, a whine. For the love of god, would people please stop using domestic silicone sealer on engines. As soon as it comes into contact with oil it breaks down, hot coolant has much the same effect, it breaks up inside the engine, clogging up the lubrication and cooling systems when over applied and it's awful to get rid of during a rebuild. The water pump housing on John's engine wash gobbed together with it, presumably because whoever had it apart previously was putting it together marooned in a desert with a tube of the stuff and no access to a Peugeot dealer, to buy the three rubber seals:

593360 £0.96

120696 £1.28

120694 £1.16

 

This is how it looked:

 

A good old clean up (paying attention to removing corrosion, particularly around where the seals seat), and it was ready for new seals and assembly, lightly oil or grease the seals to help them settle in without distorting. I grabbed a lower mileage water pump to:

 

Another thing worth mentioning is crank seals. I've seen alot of rebuilt Peugeot engines recently that have suffered annoying oil leaks using pattern seals. I don't know if the genuine seals are better, but I seem to have less bother with them and they come with protectors to aid installation without damaging the lip. The front crank seal on the TU is a bit thin and tricky to knock in square, but you can flip around the boss that goes behind the cambelt sprocket, to press in the seal square with ease, like so:

 

Be sure to fit the boss properly after obviously and on later silver top engines (with 19 tooth crank sprockets) you won't have one of these, so use the cambelt sprocket initially, then finish with a careful tap in flush.

 

I don't know why, but I find cleaning up the rocker gear very satisfying. The rockers always gleam once the AG engine cleaner and scotchbrite has worked its magic. There's a circlip on one end of the shaft, that you can remove and release all the rockers. Take a photo before dismantling to refer to when re-assembling. Once it's all clean and dry, oil or graphite grease the shaft and refit the rockers, cups, springs and bearing posts and finally that circlip:

 

That's all for today.

[Rippthrough 98]

Can't beat clean rocker arms

 

 

Mine are polished

[Sandy 191]

Haha! I can't go that far.

 

Regarding pistons, here's a few to compare:

From the left to right (piston/rod assembly weight): Honda P28 (736g), Silvertop TU3 8v (869g), TU3S(988g), 1.4 XSi (1038g), Blacktop TU5 (977g).

[Rippthrough 98]

I did lighten them first, it wasn't all for looks, honest

[RossD 44]

Blimey, look at that tiddly little con rod on the silvertop piston/rod combo :-s

[Sandy 191]

I've seen quite a few bent/broken ones of those, but the Honda one next to it is bullet proof. See how much lighter the Honda assembly is, but the detail of the design is fabulous and there's clearly no glaring weak points or surplus material.

[djinuk 2]

just to let you know i am really enjoying this thread. Just a though after its done are you going to get the car on a Rolling Road to see output.

[jonnygoodhand 0]

after its done are you going to get the car on a Rolling Road to see output.

 

That's hopefully the plan!

 

Thanks for all your hard work, Sandy. Not just on the engine, but also putting together this guide - it's a joy to read! And I promise it wasn't me who used the silicone!?!

 

Cheers,

 

John

[Sandy 191]

Haha, no worrie, I'm glad it's appreciated

[Jrod 7]

Any idea how much the mounts will cost Sandy?

[Sandy 191]

Colin's doing that bit.....

[Jrod 7]

Well I sent him a message.

[bren_1.3 1]

can the honda piston and rod be used in a TU engine? or is it just included as a comparison?

[Sandy 191]

That was the plan when I bought them, but without reducing the block height, sadly not. A shame really, because they are so nicely made, even the bolt heads are oval to improve the shape of the rod in that area. People who think VAG cars are well engineered should be forced to inspect a Honda engine.

 

Disclaimer: I haven't intended to cause hurt or offence to those who champion VAG cars or the use of domestic silicone sealant on cars and the opinions expressed in this thread may contain traces of dry humour based on my childish tongue in cheek prejudices.

Edited October 30, 2007 by sandy309

[bren_1.3 1]

would they fit the shorter alloy TU block perhaps? im not sure if the 106 rallye block is the same as the 205 euro rallye block.

[Sandy 191]

No, too tall for that! Frustrating middle ground.

[DamirGTI 342]

Hi !

 

My mate is working on the similar project and he haves problems with making the inlet manifold for weber carbs .. so if you can be so kind to revile me some measurements for making that inlet manifold i will be very grateful !!

 

Thanks !

Damir

[Sandy 191]

I can't really give you dimensions because we made a jig on the car to establish the geometry, which has been made mostly by eye and experimentation. It has to be precise at this length to avoid all the obstacles. Other maker's manifolds that I have seen, have been shorter, presumably to simplify fitment, but the IMO tract shape is compromised as a result.

 

Bit of an update:

Further to my sealant comments earlier, here's a bit of guidance to applying sealant on faces joints (without a gasket), for those that might appreciate it.

Apply a small amount of sealer to one face (Loctite 5699 in this case):

 

Spread it around the face evenly by "stippling" with your finger, remvoing excess sealant in the process, like so:

 

Fit the joint and tighten the bolts gently and evenly to the specified torque.

You should get neat sealant lines with little excess:

 

I went onto tiral fitting/fitting the gearbox. John had been looking around for a replacement MA box, but as is so often the case, he was supplied (by a breaker) a very rough box, that wasn't from the model they claimed. Since finding a decent MA box is a bit like seeking the Holy Grail and would probably let him down in time anyway; I pointed him 2 a brand new Picasso BE TU box lurking on Ebay for not many pounds!. John snapped it up, it has to be one of the bargains of the century!! The box (thankfully) bolted straight onto the 1988 TU alloy block, I modified the clutch lever for cable actuation and fitted a 205 speedo drive:

 

It looks quite comedy, the gearbox looks bigger than the engine! I'm fitting 1.9 shafts and hubs and the gear lnkages will have to be "created".

 

To make setting up the ignition timing as accurate as possible, I made a mark and pointer on the flywheel (lightened XSi one), at precise TDC:

 

Still alot to do, but munching through it gradually!

[DamirGTI 342]

I can't really give you dimensions because we made a jig on the car to establish the geometry, which has been made mostly by eye and experimentation. It has to be precise at this length to avoid all the obstacles. Other maker's manifolds that I have seen, have been shorter, presumably to simplify fitment, but the IMO tract shape is compromised as a result.

 

Hello !

 

Ok. but roughly how long must the manifold runners be ? im interested just in manifold runners length not the port diameter , shape etc.

 

Thanks !

Damir

[djinuk 2]

engine and box,, yum so clean .. stop this thread , its makes me wana go outside now and drop the tu out the gfs xs and begin stripping and cleaning lol