Lancia Beta Forum

Technical stuff => Engine => Topic started by: Gromit on December 06, 2023, 09:11:07 PM



Title: Correct cam belt tensioner pulley for 2L Beta engine
Post by: Gromit on December 06, 2023, 09:11:07 PM
I have been rereading a few threads on this subject. I understand that the original cam belt tensioner pulley for the 2L Beta engine was designed with its own specific tensioner bracket which is not the same as equivalent Fiat 2L engine cars. So you need the correct tensioner pulley for a Beta engine for it to run in correct offset alignment. Or change the Beta tensioner bracket, (mounting plate), to a Fiat 2L engine one if you are going to use a Fiat engine specific tensioner pulley? (Speculation on my part...others may care to comment if it can be done successfully from experience).

I also understand that the original Beta tensioner pulley itself, (the bearing carrier or pulley housing) is designed so that the bearing is held in place with a circlip and can be removed relatively easily and replaced as part of a cam belt service. Meaning that the pulley can be reused for a number of bearing changes until it begins to show excessive outer surface wear (that contacts the underside of the cam belt), pitting or corrosion that cannot be easily polished out.

A number of forum threads recommend this SKF bearing as the preferred tensioner bearing replacement for all Beta engine models. For example: http://www.betaboyz.myzen.co.uk/forum/index.php?topic=418.0 (http://www.betaboyz.myzen.co.uk/forum/index.php?topic=418.0)

SKF 3205-A-2RS1TN9/MT33

https://www.skf.com/dk/productinfo/productid-3205%20A-2RS1TN9%2FMT33 (https://www.skf.com/dk/productinfo/productid-3205%20A-2RS1TN9%2FMT33)

The advice is to buy the bearing from a specialist bearing supplier to get the best price and quote this bearing number. I have purchased one from Mark W, (Betaboyz UK), as I was buying other items from him and it saved on freight cost duplication.

Later after market tensioner pulleys come supplied as a complete sealed unit (bearing pressed into pulley housing), which are sold as a complete replacement pulley solution and cannot be separated for subsequent bearing only replacement. These complete after market tensioner pulleys are allegedly "getting hard to find" according to previous threads. The outer pulley diameter varies between 1600 (67mm) and Beta 2000 (71mm) engines, presumably because of the difference in belt tooth count to accommodate the longer stroke of the Beta 2 Litre engine. There are also Fiat car specific after market complete tensioner pulleys which are not suitable for Beta engines, which use a different tensioner bracket as previously mentioned. So plenty of confusion and opportunity to buy the wrong tensioner pulley from ignorant resellers who have no idea what they are selling and make grandiose fitment claims.

Ok, so all of the above is probably old news to most of you and well worn territory. The punch line of this thread post is: what is the correct replacement part number(s) for the original equipment type pulley housing with replaceable bearing held in place by circlip for a 2L Beta engine? There are frequent thread references to these housings also "getting scarce" and "hard to find" if your pulley outer belt contact surface is showing signs of excessive surface wear, pitting or corrosion. It would be helpful if the manufacturer relevant part numbers were clearly identified for future reference to assist in searching for the right part and not rely on confusing and misleading seller descriptions. I assume that in most cases this part would be supplied as a complete pulley housing and bearing assembly and not the pulley housing without bearing. Although both version part numbers would be helpful in case some pulley housings (minus bearing) still exist in dusty warehouses.

For example, is this the real McCoy: Timing Belt Tensioner fits LANCIA BETA 2.0 76 to 86 QH 4443446 ?

I have also read a thread reference to "It is a genuine SKF VKM12004" (tensioner housing/bearing combo), but this is the 67mm diameter 1300/1600 Beta engine tensioner, not the 71 mm diameter 2L engine one. Although Rossocorsa has made these comments in a previous thread:

"You must always get a tensioner for a Beta rather than a Fiat, be cynical and always check adverts carefully. A Montecarlo uses a more Fiat style arrangement and this can cause confusion with advertised parts. When new all front drive Betas had a casing with a removable bearing, if you have that type you can replace the bearing with a good quality SKF equivalent. Some 1.3 and 1.6 complete replacements such as SKF are a complete tensioner that cannot be taken apart. The complete tensioners most commonly offered these days are the smaller 1.3/1.6 ones. The 2 litre tensioner is slightly larger in diameter to account for the taller block and slightly longer belt. I don't know but I suspect it would work fine on a 1.6."

http://www.betaboyz.myzen.co.uk/forum/index.php?topic=4339.0 (http://www.betaboyz.myzen.co.uk/forum/index.php?topic=4339.0)

Are there any alternatives? Any advice or guidance re specific part numbers based on past forum member experience would be helpful to narrow down the search criteria and prevent future wild goose chases. I would like to acquire a spare pulley while they are still "hard to find" and not "impossible to find". Otherwise I guess hard chrome resurfacing of the original pulley outer surface might become the only long term option. Or an enterprising custom remanufacturing CNC machined production run of exact replica factory original steel pulley housings? A bit like what Mark W has done with replica stainless steel front brake caliper main circuit pistons.


Andrew



Title: Re: Correct cam belt tensioner pulley for 2L Beta engine
Post by: Neil-yaj396 on December 08, 2023, 09:02:25 AM
Most people just replace the bearing in the pulley. I think they are generally available and it is held in place by a circlip.


Title: Re: Correct cam belt tensioner pulley for 2L Beta engine
Post by: Gromit on December 08, 2023, 02:22:01 PM
True. I just assumed that the steel pulley tensioner bearing housing or carrier might not last forever or indefinitely without some corrosion or wear and might eventually need to be replaced. Apparently not. Perhaps that might explain why there are none around to buy in any case. No demand = no spare production and availability. Unless you happen to leave a bearing in too long which then seizes I suppose.