silent running

I've seen these alloy timing belt guides made by Tomei, Cosworth etc around and wondered what purpose they served seeing as neither my original MY98 block nor my current CDB seemed to have had one originally. Looking at pictures of where they mount, over the crankshaft front cog, they seem to need two threaded lugs on the oil pump which I don't have. In fact I don't even have the pressed metal OE item which I've seen pictures of.

Anyone shed any light on this? Anyone use them, or are they just a dress-up part for the engine really? I'll be wanting to run fairly high revs as I am using STi3/4 heads on a forged CDB, so was just wondering what they're all about?

merlin24

iTrader: (1)

Nick,
The belt guides on the crank and inner timing covers are there to help reduce cam belt whip especially on boost and over-run - the guides are normally setup to run 1.00 +/- 0.5mm clearance between the belt and guide.
As you said - you need the later oil pump with the mounting lugs cast onto the pump to use the OE/Aftermarket guides.

Mick

silent running

So worthwhile or not then Mick? Bearing in mind I'd need to buy a new oil pump to fit one?

merlin24

iTrader: (1)

Unless your doing a lot of track days where the engine is given a hard time - i wouldnt bother.
A good quality cam belt and a new cam belt tensioner is normally good enough for most road based engines.

silent running

That's all I need to know. I may be doing more track days once I get the built engine run in properly and expect to use more of the revs so it might be worth doing...I'll see how next month's budget looks!