What Cambelt Length

[wardy18 33 1 Cars]

Hi all,

 

Something which has always puzzled me but i have always taken std set up for granted but now ill be having a Hybrid XU10 8v head with XUD9 Iron Block running a DW12 Crankshaft.

 

How on earth do you decifer which length cambelt to use???

 

I know the early 205's had the 113 tooth belt and later had 114 both with different tensioners, WHY WAS THIS??

 

I would assume that the Crank Pulley, Cam Pulley and Cambelt have to match so they the top and bottom ends stay in sync with each other, ie fitting a 114 tooth belt when a 113 is the correct one would surely send out the timing on each revolution, AM I RIGHT IN THIS THEORY............??

 

With this in mind how do i calculate what should be used to join my Head and Block......I am running a Baker BM Adjustable Vernier Cam Pulley but with regards to crank pulley i have no idea, would a std 205 crank pulley fit on my DW12 crank but then does the deck height come into play and so the distance between crank and cam pulley being longer and so stretching the belt further?!

 

Hope someone can help as this must be a common issue with the many many hybrid engines out there.

 

Much appreciate any reponse

 

Simon

[welshpug 1,657]

A different tensioner was used for early/later engines.

 

Would imagine a standard XU10 8 valve setup would do the trick seeing as you're using an Iron Block.

Edited November 1, 2009 by welshpug

[Miles 331 1 Cars]

Try it and see, no idea on Derv cambelts but I guess different to Normal engine's but if the same as the petrol Iron block then it's the 114 belt

Not many hybrid's around as most people just use Mi blocks for engine upgrades over here and no one really bother's amount them being right or not for the car, I can't even recall any my self mainly due to the extra weight of them.

[Cloverleaf 1]

I would assume that the Crank Pulley, Cam Pulley and Cambelt have to match so they the top and bottom ends stay in sync with each other, ie fitting a 114 tooth belt when a 113 is the correct one would surely send out the timing on each revolution, AM I RIGHT IN THIS THEORY............??

 

No, it doesn't matter how long the belt is as long as you can get the right tension. The cam pulley and crank pulley need to be the right ratio though.

Edited November 1, 2009 by Cloverleaf

[wardy18 33 1 Cars]

No, it doesn't matter how long the belt is as long as you can get the right tension. The cam pulley and crank pulley need to be the right ratio though.

 

Ok Yeh that's what I was hoping, ill compare the crank pulleys I have to ensure I use the correct one, hopefully the crank pulley on my current XU9 ally block will fit on the DW12 crank in my new iron block, unsure if they are the same diameter, fingers crossed as this will make it the same set up as what I run now and will keep using a 205 113 tooth I think it is!

[wardy18 33 1 Cars]

Try it and see, no idea on Derv cambelts but I guess different to Normal engine's but if the same as the petrol Iron block then it's the 114 belt

Not many hybrid's around as most people just use Mi blocks for engine upgrades over here and no one really bother's amount them being right or not for the car, I can't even recall any my self mainly due to the extra weight of them.

 

So they all use the XU10J4 iron block?? Surely that's not meeting the msa regs?

[Miles 331 1 Cars]

No Alloy block with either 1905 to 2.1 CC's, I doubt anyone would notice anyway as long as the std engine mounts are used, No one did when I was racing even with a RHD phase 1 309 16v which was never made.

Personally I wouldn;t have said anything about the change and I bet you would have got away with it no problems at all

[Cameron 16]

If you have an old belt, cut it in half then route it round how you want it and note how many teeth too long / short it is. Then you can search for one with the amount of teeth you need. That's what I did when I ditched my water pump.

[wardy18 33 1 Cars]

I'm not even sure tensioner I need yet as the ones that came with the iron are very stranger and utilise a spring that is inserted into the under side of the engine mount to give it it tension but I won't be using this engine mount as I'm not running the diesel head! A little more investigation work I think

[James_R 3]

It's just going to use the XU10J2 or whatever belt, it's just an 8v on an iron block nothing too crazy the belt length was the same 114 as the tensioner is moved between them to make up the 11mm block difference

[wardy18 33 1 Cars]

Ah ok thats fine then, thanks for the help

 

Think ive run into a big problem though, i have been looking at tensioners and with the XU10 8v head on i cannot use the std XUD9 tensioner and the XUD9 block does have the placings and bolt holes for the earlier XU9 tensioner (bracket with tension wheel, spring, securing bracket type one)

 

I have never seen XU10 tensioners and i also have never had to use the later type XU9 8v tensioner

 

Any ideas guys?

[wardy18 33 1 Cars]

Here shots of the tensioner side of the block!!

 

You will notice from the side shot with the Red lines ive drawn in the the XU10 head does not sit flush with the block

 

Also notice the left XUD9 tensioner uses the engine mount to apply the tension and is then secured with a bolt in the head, 2 problems, i cannot use the XUD9 engine mount as it doesnt line up to the XU10 head and the XUD9 tensioner will not line up with the cam pulley and has doesnt line up with any bolt holes in the side of the XU10 head!!

[DrSarty 90 1 Cars]

Sorry: what was the benefit of doing this again?

[wardy18 33 1 Cars]

The XUD9 block is the ONLY Iron block that will meet the MSA Regs for Hillclimbing

 

Would you or i ever be happy if i knew i was competing and winning with say an XU10 block that is illegal for that class!!

 

Am i wasting my time with this block?

[wardy18 33 1 Cars]

How do these tensioners work?! Do they self tension or do you push the tension on then manually then tighten the blot to hold it in place, i have one in my spares but have never used one!?

 

Could one of these tensioners not be used in either of the bolt holes arrowed in red on my XUD9 block?

 

Cheers guys

Edited November 2, 2009 by wardy18

[wardy18 33 1 Cars]

Ok i have researched into these tensioners and they seem the way forward, very very simple design and tensioning and should be able to be placed in one of those 2 bolt holes arrowed to gain the correct tension!!

[wardy18 33 1 Cars]

Just been testing and it looks good, i'd say the 113 or 114 tooth 205 belt should work with this set up as ill fit the 205 crank pulley to the new crank (hopefully they are the same ID)

 

Whats your thoughts?

 

ps. please bear in mind this is showing the Diesel head and looks very tall, XU10 head is shorter!

Edited November 2, 2009 by wardy18

[Cameron 16]

You want a tensioner on the long length of the belt or you'll run the risk of jumping teeth through belt slap.

[wardy18 33 1 Cars]

Is this not a similar set up to the std XU9 205 which doesnt have the 2nd tensioner on the long length, i know what you mean though as it does look long!! I can probably fit one to the right (you can see a bolt hole by the white cable tie) to push the belt inwards slightly!! Will see what i cam do, thanks for the advice mate!!

 

What size bolt should be used with these tensioners, the bolt hole in them seems quite big, should the bolt fill this hole snug or does that not matter!? If so i might have to sleeve a smaller bolt at the bolt holes in the block are only M8 or M10 i think

[Cameron 16]

I think you have a spindle that screws into the block, then you slip the tensioner over and tighten with an M8 (I think) bolt. Your best bet is to get to a scrap yard if you can, and get the bolt and spindle off an engine that uses those tensioners. That or get somebody to post you one.

[wardy18 33 1 Cars]

Yeh definitely need to source a couple of the fittings bolts as you say for these tensioners, trouble is we don't have any breakers over here so I would need to source them new which I'm happy to do!

 

Anyone got any?