Smallport block + bigport head = Interferance engine ?

**takai** · 21-03-2008, 09:25 PM

Just make sure they are using something more sophisticated than a dremel. Ive seen a dodgy bros use a dremel before.

**too_quick** · 21-03-2008, 10:47 PM

http://www.roadandtrack.net.au/

Thats the mob thats doing my machining and engine work from now on, Haven't heard a single bad rumour about them and a good mate works there. UMR engines did awesome work just they are very expensive and don't specialize in 4A engines but road and track has ALOT more experience. They arnt dodgy

Ive heard of people doing it but i all ways thought it was dodgy and only back yard blokes did it but it seems i was under the wrong impression.

Are the Toda/HKS timing belts any better than say a gates racing timing belt or a genuine Toyota item ?

**TooF** · 21-03-2008, 10:52 PM

feral: add a couple of snapped belts, ive done one, adam did one, erin did one. all before the factory service schedule.

**too_quick** · 21-03-2008, 11:14 PM

Originally Posted by The Real Roadrunner

why not get the valve reliefs cut out if your worried? easiest way IMO

cheers
linden

So got any more info about this procedure ?

**oldeskewltoy** · 22-03-2008, 04:14 AM

possible causes for a belt to break/strip prior to mileage.... TIME... rubber begins to deteriorate immediately after it is manufactured. Frequently timing belts have time intervals as well as mileage ones......

cutting reliefs is easy on forged pistons(even with a dremel....not by me.... but), cutting deeper releifs on a cast piston...... not something I'd recommend

**Grega** · 22-03-2008, 07:50 AM

des. like linden said, flycutting is fine to pistons. its not dodgy.
talk to terry @ road and track he is a good guy and knows his stuff - he's been around 4AGE's long enough to know them well mate.
if at all in doubt, plasticine and dummy assy the head/block and then rotate by hand to check for clearance matey.

**q.c.autosports** · 22-03-2008, 01:00 PM

Modeling clay and mock up assembly will take the guessing game out. You'll be safe with .060 valve to piston clearance.

**Ben Wilson** · 22-03-2008, 03:56 PM

I've personally never seen a belt snap, but I've seen a crank pulley fail and spit the woodruff key out. This was on a smallport motor with a shaved bigport head, he was running stock lift cams so there was no damage...

**Dimitri** · 23-03-2008, 09:49 AM

yes shearing the keyway is a pretty common fault.

also one of my cams jumped a tooth the other day, had me scratching my head for a while.

**feral4mr2** · 23-03-2008, 03:41 PM

Originally Posted by Dimitri

yes shearing the keyway is a pretty common fault.

IMO if the crank pulley bolt is torqued correctly this shouldnt happen.
(a lick of loctite shaft stuff on the crank pulley before slipping it on helps too).

Originally Posted by TooF

feral: add a couple of snapped belts, ive done one, adam did one, erin did one. all before the factory service schedule.

too much tension on the belt maybe...

**Ben Wilson** · 23-03-2008, 04:46 PM

Originally Posted by feral4mr2

IMO if the crank pulley bolt is torqued correctly this shouldnt happen.
(a lick of loctite shaft stuff on the crank pulley before slipping it on helps too).

On this one, the top of the keyway cracked and literally popped out. The bolt was still tight...