16 replies to this topic

[TheHippo]

Hi All,

 

I'm thinking of changing my camshaft for a Minispares Evolution001 (in a standard 998 with Stage 1 exhaust and twin HS2s). I know this is a topic that will have been discussed many times before, but I can't find the info I'm after. 

 

I'm not looking for advice/opinions as to whether or not it's worth doing - I'm hoping to benefit from your collective knowledge/experience as to the actual practicalities of it. My questions are:

 

1) Will duplex timing gears fit straight in with the standard timing cover I've currently got? (I think it should, but want to check as I have seen mention of 'duplex timing covers').

2) Am I correct in thinking that I will be able to remove and replace the followers via the plates on the back of the engine?

3) Can I determine, before taking it apart, whether/what offset of woodruff key I will need?

4) Are there any other components (e.g. locktabs, seals etc) that I will need to replace while I'm at it? (I'm aware of the 'triangle plate' and timing cover gasket and will replace these).

5) I'll purchase a timing disk and some assembly lube, but are there any other 'special' tools I will need? 

 

If you have any other hints or tips, I'd be glad to hear them!

 

Thanks in advance,

 

Dan

TheHippo

[Spider]

In reply to your well laid out and thought of questions;-

 

1) Yes. Duplex Gears fit in all covers, however, if it is the type that's used with a Tensioner, you usually need to knock flat a dimple that's in the cover at the approx 4 O'Clock position.

 

2) Yes.

 

3) No. You'll need to do an assembly with a known or standard Key, measure the error and then obtain the right key. A way around this maybe to obtain an adjustable Sprocket.

4) I would replace the Oil Pump, they do cop a bit of a hiding as far as wear goes, Water Pump too. Check as many items as you can while it's out and in bits.

5) You'll also want a Dial Gauge (metric or Imperial) and to make life a little easier, a magnetic base stand for it.

[TheHippo]

Spider,

Thanks for the reply - really helpful.

1) I understand the tensioner becomes optional with duplex gears - I wasn't planning on using one.
2) Great.
3) Understood.
4) OK, I'll look at doing oil pump. Water pump is only a few months old.
5) I have a DTI with magnetic base.

Thanks again,

Dan
TheHippo

(Edit - numbering, whoops!)

Edited by TheHippo, 30 July 2021 - 09:38 AM.

[Ethel]

Expect you know, but just in case... You'll need to countersink a couple of screw holes behind the crank pulley and swap the screws.

 

The triangle plate will likely be reusable, but it's not expensive. You might  need to adjust the shimming though.

 

Rocker cover gasket?

 

Back off all the tappet screws and slide the rockers over (or remove the rocker shaft) to get the pushrods out - if you don't want to buy a head gasket. Also make sure everything (e.g. pushrods) goes back where it came from.

[Steve220]

I know you don't intend to use a tensioner, however i would highly recommend it on a duplex.

[TheHippo]

Ethel,

Thanks. I knew there were two screws but didn't know they'd need countersinking.
I figured it's better to just fit a new plate, given how cheap it is. I guess I'll order a couple of shims too, just in case.
I think I've got a spare rocker cover gasket, but will order one if not - good shout, thanks.
I was hoping to use that approach, rather than removing the head. And will be sure to put pushrods etc back in previous positions.

Thanks,

Dan
TheHippo

[TheHippo]

Steve220,

Thanks for that - I will use one if consensus is that it's better to.

Dan
TheHippo

[Steve220]

They do stretch and will rattle a bit. I didn't at first, but when i pulled the engine a year later, i added one and it's much quieter.

[whistler]

You could stick with single chain but use an IWIS chain https://www.somerfor...wis-heavy-duty.

[TheHippo]

Thanks for the replies so far.

 

Are there any oil seals or other 'consumables' that should be replaced when I do it?

 

Dan

TheHippo

[Spider]

I figured it's better to just fit a new plate, given how cheap it is.

 

Given this is actually a Babitt Bearing (Thrust Plate), it is a wise idea I feel to replace it.

 

 

Steve220,

Thanks for that - I will use one if consensus is that it's better to.

Dan
TheHippo

 

I don't know if it is the consensus, but for what ever it's worth, I too fit them, even on the Duplex ISWS Chains.  For any road car, I can't see a down side.
 

[TheHippo]

Spider,

 

Yes - I understood it was a bearing face, hence decided I would replace it.

 

I have read some conflicting information/opinions (inevitably) around the tensioners. Some people seem to suggest that they wear very quickly when used with duplex chains because they dont sit in the right place. If I do decide to refit it, would you advise purchasing a new one, or would the old one be fine? 

 

Dan

TheHippo

[Spider]

My own experience with the Tensioners is, yes, I have been using the Simplex type Tensioner as that's all that's been available since I started fitting them, however, I've always ran with the Factory fitted Tensioner, while I have a new replacement one in the draw, I'm yest to find one that needs replacing. The one that's in my Missus's Moke has done circa 250 000 km and still no sign of needing to replace it anytime soon.

[whistler]

What would be useful is the method of setting up the standard tensioner. My first 1275 rebuild in 2016, the tensioner was really gouged so I replaced it with a Minispares one. That snapped after about 2000 miles so I fitted duplex with no tensioner. My next 1330 rebuild had a gouged tensioner so I fitted duplex without tensioner. Same with next 1275 and 1098.

 

I would have preferred to stick with a simplex (IWIS) chain with tensioner if I was confident of correctly install the thing.

[TheHippo]

Whistler - having not replaced one before, I'm not sure of the setup, so would you mind explaining what about the tensioner is difficult to set up?

 

I would have assumed that it was essentially a sprung arm...?!