Dilemma with camshafts

[m1tch]

Hi all,

I have a bit of a dilemma with my camshafts for my build, here is my issue:


I have a set of reground pipercams for forced induction
I have measured the clearance with them fitted to the cylinder head with the valves
The base circle diameter has been ground down by Piper meaning that there is quite a lot of clearance between the cam and the bucket
The shimless bucket required to bring them into spec don't exist (would need buckets between 74 and 90 equivalent) - largest bucket I can get is a 72

Here are my options:

1. Fit shimmed Supertech buckets and shims to bring them into spec and use the Piper cams - downside is I would need to buy a full set of shimmable buckets as well as the fact that I don't really want to run a shimmed bucket at higher RPM as they can fail.

2. Bin the Pipercams and buy a set of Crower stage 2 FI cams from the states - I believe these are from new blanks so would have the correct base circle diameter, I would still need to probably buy a few buckets but I have 48 buckets of various sizes in the garage but at least they will be within spec to use OEM shimless buckets.

3. Bin the Pipercams and fit a set of OEM camshafts - these will work fine with the OEM shimless buckets but I might be down on power vs the performance cams.

Basically:

Option 1 = Some cost, will bring the clearance into spec but might have a catastrophic failure
Option 2 = VERY VERY expensive but should allow the engine to make the most power and retain shimless buckets
Option 3 = lowest cost, will keep shimless buckets but won't make as much power

Not sure what to do really, I have dropped Pipercams an email to see what they say as they have basically provided me with a set of cams that are unusable for the OEM setup (although still technically usable if converting over to shimmed buckets).

[thetyrant]

Have you tried stock cams in head to see if you can get correct clearance since you rebuilt head?

 If so i would try get refund on piper  cams and run stock they should make plenty of power, you can always swap to crowers in future if you want that last bit of topend.

You could also get valve seats recut to sit valves in more to close up clearance for pipers, might be cheapest way of using them if they won't refund.

[Nvy]

Id do what thetyrant said. On the plus side the OEM will spool the turbo way faster due to the small valve overlap.

Id also look into CAT cams as their FI cams have less valve overlap than OEM but unsure if they are making them from blanks or not. They have some specs on their site.

[Carolyn]

Have you tried stock cams in head to see if you can get correct clearance since you rebuilt head?

 If so i would try get refund on piper  cams and run stock they should make plenty of power, you can always swap to crowers in future if you want that last bit of topend.

You could also get valve seats recut to sit valves in more to close up clearance for pipers, might be cheapest way of using them if they won't refund.

These seats can't be cut or ground unfortunately.

[m1tch]

I have found that Supertech do their own cam followers that I can then run the supertech plates to make up the clearance. Another option is to run lash caps and OEM followers, I can get 5.5mm lash caps, however I think the skirt of the lash cap will be too long meaning that it would actually be resting on the keepers, also the underside of the OEM cam follower is machined only for the 5.5mm valve with the rest of the post being untouched. If I were to run lash caps they would sit on the keepers on one side and on the unmachined underside of the follower on the other side.

I think my option would be to either run stock cams or go all out and get a full set of supertech lifters and plates to make up the clearances - still don't like the idea of having any sort of shim in there but at least they are under bucket rather than on top!

The piper cams I have run a 32 degree overlap, looks like the stock overlap is 29 degrees and it looks like the Crower cams have a 14 degree overlap.

[thetyrant]

These seats can't be cut or ground unfortunately.

Thats a bugger

[thetyrant]

I have found that Supertech do their own cam followers that I can then run the supertech plates to make up the clearance. Another option is to run lash caps and OEM followers, I can get 5.5mm lash caps, however I think the skirt of the lash cap will be too long meaning that it would actually be resting on the keepers, also the underside of the OEM cam follower is machined only for the 5.5mm valve with the rest of the post being untouched. If I were to run lash caps they would sit on the keepers on one side and on the unmachined underside of the follower on the other side.

I think my option would be to either run stock cams or go all out and get a full set of supertech lifters and plates to make up the clearances - still don't like the idea of having any sort of shim in there but at least they are under bucket rather than on top!

The piper cams I have run a 32 degree overlap, looks like the stock overlap is 29 degrees and it looks like the Crower cams have a 14 degree overlap.

Have you had stock cams in for clearance check ?

[Petrus]

Id also look into CAT cams as their FI cams have less valve overlap than OEM but unsure if they are making them from blanks or not.

The cams they offer are from blanks but when asked they will regrind too.

[m1tch]

I have found that Supertech do their own cam followers that I can then run the supertech plates to make up the clearance. Another option is to run lash caps and OEM followers, I can get 5.5mm lash caps, however I think the skirt of the lash cap will be too long meaning that it would actually be resting on the keepers, also the underside of the OEM cam follower is machined only for the 5.5mm valve with the rest of the post being untouched. If I were to run lash caps they would sit on the keepers on one side and on the unmachined underside of the follower on the other side.

I think my option would be to either run stock cams or go all out and get a full set of supertech lifters and plates to make up the clearances - still don't like the idea of having any sort of shim in there but at least they are under bucket rather than on top!

The piper cams I have run a 32 degree overlap, looks like the stock overlap is 29 degrees and it looks like the Crower cams have a 14 degree overlap.

Have you had stock cams in for clearance check ?

I have gone through all of the clearance checking, I don't have stock cams spare anymore as Pipercams took them as a core exchange - looks like they have reground OEM cams rather than used fresh blanks meaning that the cams are unusable using the OEM method which I am really rather angry about as they aren't fit for purpose.

[Joesson]

I have found that Supertech do their own cam followers that I can then run the supertech plates to make up the clearance. Another option is to run lash caps and OEM followers, I can get 5.5mm lash caps, however I think the skirt of the lash cap will be too long meaning that it would actually be resting on the keepers, also the underside of the OEM cam follower is machined only for the 5.5mm valve with the rest of the post being untouched. If I were to run lash caps they would sit on the keepers on one side and on the unmachined underside of the follower on the other side.

I think my option would be to either run stock cams or go all out and get a full set of supertech lifters and plates to make up the clearances - still don't like the idea of having any sort of shim in there but at least they are under bucket rather than on top!

The piper cams I have run a 32 degree overlap, looks like the stock overlap is 29 degrees and it looks like the Crower cams have a 14 degree overlap.

Have you had stock cams in for clearance check ?

I have gone through all of the clearance checking, I don't have stock cams spare anymore as Pipercams took them as a core exchange - looks like they have reground OEM cams rather than used fresh blanks meaning that the cams are unusable using the OEM method which I am really rather angry about as they aren't fit for purpose.

If the work done is "not fit for purpose", and it certainly sounds like it, that is surely one good reason for a refund and replacement of your OE cams.

[m1tch]

I have found that Supertech do their own cam followers that I can then run the supertech plates to make up the clearance. Another option is to run lash caps and OEM followers, I can get 5.5mm lash caps, however I think the skirt of the lash cap will be too long meaning that it would actually be resting on the keepers, also the underside of the OEM cam follower is machined only for the 5.5mm valve with the rest of the post being untouched. If I were to run lash caps they would sit on the keepers on one side and on the unmachined underside of the follower on the other side.

I think my option would be to either run stock cams or go all out and get a full set of supertech lifters and plates to make up the clearances - still don't like the idea of having any sort of shim in there but at least they are under bucket rather than on top!

The piper cams I have run a 32 degree overlap, looks like the stock overlap is 29 degrees and it looks like the Crower cams have a 14 degree overlap.

Have you had stock cams in for clearance check ?

I have gone through all of the clearance checking, I don't have stock cams spare anymore as Pipercams took them as a core exchange - looks like they have reground OEM cams rather than used fresh blanks meaning that the cams are unusable using the OEM method which I am really rather angry about as they aren't fit for purpose.

If the work done is "not fit for purpose", and it certainly sounds like it, that is surely one good reason for a refund and replacement of your OE cams.

I messaged Pipercams yesterday and will see what they say, I mean technically they will work, but not using the OEM method of setting clearance. I think the Crower cams use new blanks so the base circle diameter is the same as stock so you can use the OEM method of setting clearance. I can only think that Pipercams just assumed that the clearance is set via movable shims rather than shimless buckets.

[Joesson]

@m1tch said:
" I can only think that Pipercams just assumed that the clearance is set via movable shims rather than shimless buckets."


"Never assume" was my mantra for guidance of my new "colleagues" when I was working.

[m1tch]

@m1tch said:
" I can only think that Pipercams just assumed that the clearance is set via movable shims rather than shimless buckets."


"Never assume" was my mantra for guidance of my new "colleagues" when I was working.

I agree - will see what Pipercams say, I think they just cut corners to save the cost of a new cam blank

[thetyrant]

I have gone through all of the clearance checking, I don't have stock cams spare anymore as Pipercams took them as a core exchange - looks like they have reground OEM cams rather than used fresh blanks meaning that the cams are unusable using the OEM method which I am really rather angry about as they aren't fit for purpose.

Ok thats a shame, im not clear if you checked the clearance with oe cams before sending off to Piper ?  im guessing not from what you have said but im just trying to work out if if might not be the cams but other work on head like new aftermarket valves for example that might be causing the clearance issue.

Ive seen in before where aftermarket valves have caused this issue either due to thicker heads or longer/shorter stems, often the valves are supplied longer than required and need a trim to get clearance required, not so easy to add length though, especially if seats can not be cut

[thetyrant]

Regrind is common and you can usually tell from price, we get new chilled iron cam blanks made here for the old Aston vb6 engines and they are quite pricey, more than the grinding!   if old cams are reground correctly taking into account valve clearances etc there is no issue with doing it but as they are removing material it needs careful planning, they should be aware of the bucket shims on these cars so maybe they have a solution. 

Will be interesting to see what they say about if if you can get an answer.

[Call the midlife!]

After only a brief look on the Piper website I can't see an option for vvti, only Li for the Celica.
Maybe there's been some crossed wires, lack of understanding at some point in the ordering process if indeed they have been wrongly ground to 2zz specs.

[Petrus]

not so easy to add length though, especially if seats can not be cut

The thing could be valve caps. That is a very common ans safe shimming solution too. Thin caps and thin buckets might do the trick.

[Call the midlife!]

Just as an aside to the main problem, be mindful of your terminology when you're contacting Piper. This engine doesn't use "followers" and there's no way you could use them to solve the problem.
If you've mentioned followers in your communications with Piper previously it could've led them down the 2zz path.

[Call the midlife!]

Just humour me here David, purely brianstorming to look down every avenue.
You have removed the standard spring seats and fitted the Supertech seats the right way up haven't you?
Again just throwing stuff out there, we all make weird mistakes at times.
It might be of benefit to share the images of your clearance measurements here as well, they all looked a bit too uniform to me when you put them on Facebook.
It might let some fresh eyes see something others have missed.

[m1tch]

The thinnest lash cap I can get is a 1mm cap, would need a negative number bucket on the intake side to get to clearance with that - I could go with the Supertech follower and shim for all 16 of them which would sort the issue out but ideally I wouldn't really want to be running shims.

Basically I can't get shimless buckets thick enough but I also can't get lash caps that are thin enough to work with any shimless buckets. An option is to grind down the post on the OEM bucket to smaller than stock and fit a lash cap but not really happy with that option either.

I have installed the seats the correct way up - they are dual valve springs with the seat sitting inside the springs to centre them.

Below are the specs I have including the bucket thickness and the clearances - the installed height of the springs would be the same, the cams are 100% reground and I have used buckets in basically the same range so I would expect things to be fairly uniform - the clearances were done with a feeler gauge so its only as accurate as I could go. Worth noting that the 'bucket number' on the sheet below relates to the actual bucket number when measuring it rather than the actual number on the bucket.

[Joesson]

@m1tch said:
" I can only think that Pipercams just assumed that the clearance is set via movable shims rather than shimless buckets."


"Never assume" was my mantra for guidance of my new "colleagues" when I was working.

I agree - will see what Pipercams say, I think they just cut corners to save the cost of a new cam blank

"just cut corners" is exactly what they've done !

[m1tch]

@m1tch said:
" I can only think that Pipercams just assumed that the clearance is set via movable shims rather than shimless buckets."


"Never assume" was my mantra for guidance of my new "colleagues" when I was working.

I agree - will see what Pipercams say, I think they just cut corners to save the cost of a new cam blank

"just cut corners" is exactly what they've done !

If the base circle diameter was 0.3mm larger then everything would be fine - might still run the stock camshafts though, looking at the specs on the Pipercams they aren't really much different to stock.

[m1tch]

I am going to modify some stock buckets and remove some of the post on the inside to create an OEM bucket that is less than OEM (there is still a fair amount of post on the inside of the buckets even with the lower numbered bucket).

The smallest lash cap I can find is a 1.35mm cap so I should be able to reduce the bucket thickness down to then be able to accept the lash caps.

Not ideal but an option I am going to look into.

[thetyrant]

Im not sure i would go down that route as would imagine its going to be difficult to accurately machine out the post in the buckets to allow for the lash cap, it will be very tough material as well due its required usage possibly just a hardened surface which once removed could be too soft, also as you need various sizes it would be a hell of mission imo

I would think you would be better off removing the material off the valve stems then fit the lash caps if you continue with the pipers.

[m1tch]

Im not sure i would go down that route as would imagine its going to be difficult to accurately machine out the post in the buckets to allow for the lash cap, it will be very tough material as well due its required usage possibly just a hardened surface which once removed could be too soft, also as you need various sizes it would be a hell of mission imo

I would think you would be better off removing the material off the valve stems then fit the lash caps if you continue with the pipers.

I am going to see what Pipercams say first, ideally I don't really want to be running shims at all, there isn't a huge amount of clearance at the top of the valve stem for much grinding else the skirt of the lash cap might touch the collets etc.

I would only need to remove around 0.5mm off the posts within the followers, will try on a junk one first to see what its like but probably won't need much to remove material.