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dave88sw

A few V8 questions

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dave88sw    20

Hi,

I want to change the cam shaft on my 3.9 V8 (No issues as such with the current one, it's not tapping or anything but it's done 130,000 and probably hasn't ever had one).

I've done quite a few in the past but can't for the life of me remember:

Do you have to remove the sump to get the timing cover off? (Can't remember whether the oil pick up bolts up to the bottom, it's a serp engine.)

Is there a sump gasket for a V8 with steel sump?

 

Is there anything else to do while i'm in there? I'm thinking cam, both timing gears and chain and a set of followers from turners.

Thanks

Dave

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Davo    47

I've got the H180 cam Turner sells, and other parts from them, too. It's worth doing the chain and gears too. The oil pickup bolts to the block, so no worries there. You can get the timing cover off with the sump in place but it's a bit bodgey. It's worth taking off the sump and checking the mains bolts and to give it a good clean, because you never know what's happened over the years. There might be a gasket - you never know what someone has done! Some people use a gasket with a steel sump, some don't. 

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dave88sw    20

Thanks for the response, was the H180 a worthwhile upgrade?  I'm happy  to spend some money on it if it'll give an improvement but i only really use it on road or for light off roading, its never really pushed that hard.  Good point, I might well do that but it's worth knowing anyway so i know i won't have to buy any extra gaskets or o-rings. 

I seem to remember the steel sumps i've had off in the past have just had rtv on them but it's been so long since i worked on one.

I was going to change the chain and gears anyway, i'm tempted by a duplex chain, just for longevity more than anything.  What are peoples opinions on this? :

http://www.v8tuner.co.uk/product.php?id=699

Thanks

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L90-v8    3

if you do want to use a gasket I found a rubber item to be far superior than the cork one as they imo are garbage same also for the rocker covers the rubber ones seem to seal a lot better for longer but you will already be using them on a 3.9

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Davo    47

Yes, the H180 is worthwhile, (and I feel that it must be good if Turner sells them - they are more engineers than salespeople), and just gives the engine a little bit extra. I use a duplex chain as well, even though the original type seems to last well, but it's an easy upgrade. You do have to grind a bit off the inside of the timing cover to allow for the extra thickness of the chain, which is easy enough to do if you're careful and do it in stages. You just put some Plasticine on the cover and see where the chain will rub, and keep doing that until you've ground off just enough metal. 

And as above concerning the cork gaskets - I've got one on the sump and it wasn't my best idea! 

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FridgeFreezer    369

This is the one I put in the 109 (4.6), Piper's version of a stump-puller, no complaints here:

v8_camspec.jpg

For info, the later P38 timing gears are all steel. You can't fit duplex in the P38 front end (too narrow by miles) but the advice from V8Tuner was it's not worth worrying about anyway.

 

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dave88sw    20

Thanks for the info, it's given me plenty to think about.  It would be nice to have a little bit more poke, it goes very well (it's still running standard hotwire injection but has megajolt taking care of the spark- the megajolt alone made a huge difference) but it does lose speed on steep hills on dual carriageways.

Perhaps the duplex chain isn't 100% necessary, i didn't realise the timing chest would need altering.  I assume the p38 gears are a straight swap? That sounds like a good option.

 

Thanks

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FridgeFreezer    369

I don't know if P38 gears will be 100% in an older lump, but my 4.6 started with a 3.5 / 3.9 front cover and duplex chain and then I switched it to std. P38 everything when I did the cam.

P38 cams are shorter in the nose due to the shallower front cover, may affect the timing gear, can't remember.

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dave88sw    20

Ok thanks, i'll try and do some research but i imagine it would work fine if i used the corresponding P38 cam and full gear set, with the megajolt i don't need the dizzy drive.

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dave88sw    20
9 hours ago, Davo said:

Yes, the H180 is worthwhile, (and I feel that it must be good if Turner sells them - they are more engineers than salespeople), and just gives the engine a little bit extra. I use a duplex chain as well, even though the original type seems to last well, but it's an easy upgrade. You do have to grind a bit off the inside of the timing cover to allow for the extra thickness of the chain, which is easy enough to do if you're careful and do it in stages. You just put some Plasticine on the cover and see where the chain will rub, and keep doing that until you've ground off just enough metal. 

And as above concerning the cork gaskets - I've got one on the sump and it wasn't my best idea! 

I agree the original type last well in as much as i've never personally experienced a broken chain but they seem to suffer stretched chains fairly quickly.  I've been trying to find a bit more info on the alterations to the timing chest but it seems that some fit fine and others need a little grinding to clear.  Can you confirm what type of cover you have? Is it serp/interim (serp but with dizzy)/v belt?

If I can't make my mind up i'll just fit a good quality set of standard parts but a bit more longevity would be nice, the engine appears to be in otherwise good health and it's serviced every 3000 so i'm hoping not to go in again anytime soon.

Sorry for all the questions, if i could afford to have the car off the road for long periods i'd just pull it apart and see what fits but realistically i need to get the job done over a few days so i'd really like to get all the parts lined up in advance.

Thanks again.

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garrycol    44

Remember the standard 4.6 cam does not have the dizzy drive as there is no dizzy (obviously) so the timing cover is not as long - hence no room for a duplex chain.  If the timing cover from another engine is used you need to ensure the front end of the cam shaft matches the timing cover.

I dont think the short 4.6 cam works with a timing cover with a dizzy hole but not sure - just use a 3.5/3.9 cam shaft with a 4.6 grind.

 

Garry

 

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dave88sw    20

Ah ok, so using a p38 cam in my current cover isn't an option.  I'm just finding it difficult to find information about an interim engine, mine is a serp so has crank driven oil pump but it did originally have a distributor.  I've seen a few people say the issue comes with clearance to the oil pump in the front cover.  It's looking more and more like i'll just have to stick with standard parts.

 

Thanks

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Bowie69    382

Sounds like you just need the H180 version with a dizzy drive on the end of it, in other words, any pre-distributorless cam, which means your choice is actually greater, last time I looked.

You are right though, the interim engines are a pain!

Lots to choose from here: http://www.v8tuner.co.uk/category.php?id=9

 

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L90-v8    3

fridge freezer is the duplex kit all steel like the 4.6 p38 item

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Davo    47

Sorry, I completely forgot about the different timing covers. Yes, duplex sets are all steel. 

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FridgeFreezer    369

Most cam co's will do any cam with any grind you ask for, when I bought mine it wasn't listed on Piper's website for the later lumps, so I called them up and they basically said you can have the stump puller in any flavour you like.

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dave88sw    20

Thanks again guys, i can mull over the cam choices before buying, whatever i go for as said will just have to have a distributor type front end the same as the original.

The only thing i'm still a little confused about is whether a duplex chain will go in an interim front cover without alterations? Is the interim front end just as deep as the previous v belts front cover?

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Davo    47

This is the timing cover with a crank-driven oil pump but able to drive a distributor, isn't it? I just had a look at the photo in Des Hammill's book and yes, that's the same inside as the older type. There has to be room for the cam to drive the distributor, so it should be fine. Just check and grind as I described it above. 

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dave88sw    20
17 hours ago, Davo said:

This is the timing cover with a crank-driven oil pump but able to drive a distributor, isn't it? I just had a look at the photo in Des Hammill's book and yes, that's the same inside as the older type. There has to be room for the cam to drive the distributor, so it should be fine. Just check and grind as I described it above. 

Brilliant, thanks very much, appreciate you looking it up :) .

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