pushrod V8 specific question

[KKtrips]

OK so I installed my cam into my 308 on the weekend and when I slid the cam in - all was tickedy boo.

 

I put the cam retaining plate on and the cam seemed to get hard to turn. I threw the cam gear on and I could turn the cam still but it had noticeable resistance. I timed up the motor and put the timing chain on and when turning the whole engine over with a strongarm it felt fine and not at all notchy.

 

So I left it at that as I ran out of day but thinking the last 2 days I got very nervous so tonight I pulled it all apart again to confirm what I thought I felt. Sure enough - the cam sitting in loose and it turns easy enough. It doesn't spin like an old worn cam does but it turns with ease - it's a new camshaft on those bearings - so I feel that is allowable and will bed in no doubt.

 

As soon as I put the retaining plate on and tighten it up I then can't turn the cam easily by hand. I get a small bit more leverage like a small screwdriver or the cam gear on and I can turn it by hand but it feels wrong - like undoing a rusty bolt with your fingers tight. So I am not at all comfortable with that.. I thought the retaining plate may have been too big for the locating groove in the cam but I put the plate in and it's free to move around the groove.

 

So I ask you guys - what else could this be?

 

I am currently suspecting the frost plug on the backside of the motor is in too far and because the aftermarket cam could be fractions of an inch slightly longer than the factory one then it is binding up when I put the retaining plate by pushing the south end of the cam hard up against the frost plug.

 

Yes the frost plug is the correct way around (ie with the concave side facing inwards which is opposite to normal frost plugs) But is it too far in? I took some photos and they are below.

 

Does anyone know if it looks too far in? It can most probably come out another 2-3mm and still be firmly in place which will be plenty because the cam only goes tight in the last fraction of a mm of pushing in.

 

If it looks too far in can I use the camshaft as a "drift" to push the frost plug out a little bit? The rough cunt in me says "hell yeah - she'll be right" but cautious me says "fuck NO - you rough cunt!!"

 

Anyhow - ideas/suggestions wanted - but please don't fill this thread with bullshit guessing - I've done enough guessing on my own and want to start seperating guesses from facts. 

 

Cheers

 

Photos...

 

 

 

 

 

 

 

 

 

 

[eke_zetec_RWD]

Try slide the cam in further than the groove and if it does then the frost plug isn't the issue.

[Dell'orto]

I don't know if thats in too far but I'd certainly not be keen to use the cam as a drift!

[KKtrips]

Cheers Jase. I can slide the cam in and the groove looks either flush or just ever so slightly lower than the face the retainer plate bolts to.

Are you saying it should sit comfortably below that face?

 

Big question is can I use the cam as a drift? I'm being lazy and can't be bothered taking all the lifters rockers and pushrods fully out again.. LOL

 

Edit - I suppose I should just pull the cam out and use a long 3/8" extension I have as a drift (or 2 extensions coupled if I don't have enough reach)

[vivaspeed]

Dumb question maybe, seeing how I know very little about pushrod V8s (silly things, cam should be on top of the head), but what controls the end float in the cam?  Is it the front retaining plate?

 

/not helpful in solving KK's problem

[KKtrips]

Dumb question maybe, seeing how I know very little about pushrod V8s (silly things, cam should be on top of the head), but what controls the end float in the cam?  Is it the front retaining plate?

 

/not helpful in solving KK's problem

Yeah retaining plate has thrust faces on it.

[sheepers]

take the cam out and have a look at the back face. you should be able to see any marking on it if it is rubbing.

when the cam is out use an old one to move the frost plug back a bit, then put the good cam back in. if its still binding you know its not the frost plug. 

[sheepers]

also, if the retainer plate is warped it might bind in the grove as you do it up?

[KKtrips]

also, if the retainer plate is warped it might bind in the grove as you do it up?

Did think that possibly the plate was bent but the old cam I pulled out was turning absolutely fine - the retainer plate is about 8mm thick.

 

Could be the old cam cam retaining groove was worn so it wasn't noticeable but hard to see how the plate could be warped as there is nowhere really to leverage on it.

[sheepers]

its worth a look. 

[sheepers]

it wont take much, like less than you can see for it to cause the cam to feel tight. 

[Rookie]

Do you have some layup dye? Chuck it on possible offending areas and see if it gets worn off?

[cletus]

if you loosen the bolts on the retaining plate slightly does it get easy to turn again?

 

id do as mentioned, see if the cam has made any marks on the plug.

 

if thats not whats binding, maybe its the new cam running on an un worn section of the cam bearings?

 

cam bearings can be a bit of a challenge to press in right/get cam turning perfect

[KKtrips]

Cheers guys all good stuff.

 

I just had a word to the Shazfather of 308's and he has calmed any fears - he said it's most probably a small hint of carbon on the last cam bearing where the old cam didn't run because it was a smidge shorter.

 

Also when I told him I was using Redline assembly lube he was all lightbulbs as it is renowned for dragging like fuck and it most probably also built up a bit on the the end of the cam which is hydraulicing against the end of the block/frost plug.

So I'm throwing it together tonight and when I run it up then it'll be fine..

 

FYI - the "frost plug"  doesn't have a shoulder as such so it can't be that. It's a dome plug which you hammer to flatten out and this forces it into it's seat in the block.