Another intermediate cover question.....

seight · Post by **seight** » Wed Jul 18, 2007 12:03 pm

.....does anyone know if an intermediate cover will fit over a duplex timing chain?

My (4.2 short nose crank) engine is built up right now with an SD1 cover but I am going to replace it with an intermediate. My cam which is an MC1 needs to be timed to 108 so I need a vernier (which I have installed) but I am concerned that this may not fit due to the crank driven oil pump in the intermediate cover.

Anyone know for sure?

thanks
Mike

ihatesissycars · Post by **ihatesissycars** » Wed Jul 18, 2007 12:27 pm

Mine clears my JP Duplex chain but only just. It has ever so slightly touched the dizzy holes casting on the inside so a small amount of grinding would be required there to be on the safe side. If you're not using a dizzy then you could just chop that bit out completely.

Also there is evidence of the bottom of the chain coming very close to the oil pumps back plate. It hasn't touched but there is a definate lightening of the brown coating on the plate where the chain runs.

There's no signs of damage to the chain though.

seight · Post by **seight** » Wed Jul 18, 2007 3:17 pm

Ah, cheers.

I've currently got a Piper vernier setup installed for now and had to remove the small lug casting of the dissy section of the SD1 cover as it would have hit the heads of the screws on the cam gear.

Am I right that that JP is not a vernier but has multi-way crank sprocket to allow you to adjust the cam timing? I know that wouldn't be as accurate as a vernier but it would probably be close enough if it can to 4 degrees.

thanks
Mike

ihatesissycars · Post by **ihatesissycars** » Wed Jul 18, 2007 3:23 pm

Yup thats the JP chain set. A choice of keyways are available.

A cam button would solve the problem at the top of the chain but there's no where on an interim cover for it to press against so it'd have to be a cam thrust plate which only later blocks have (I have one of these spare!)

seight · Post by **seight** » Wed Jul 18, 2007 3:43 pm

I've got a cam button in my current (built but not run) setup and I'm sure when I fitted it that it only goes against a flat part on the SD1 cover, so that's probably no different - I think!

I like the idea of the retainer but my block does not have the holes and I'm not sure my cam is machined correctly - will check when I *eventually* get back to work on it.

I want to do away with my dissy so I will need one or the other.

I would love to take your 4.6 block off you but I'm afraid the amount of time, effort and of course money put into getting my 4.2 built that if 'the boss' found out I'd bought another block then I'd be sleeping in the garage! Wish I'd known you can't get 4.2 pistons +.020 before I started !!!!

thanks
Mike