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Head/camshaft journals are oversized?? What the...

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ziggo0

10+ Year Contributor
774
7
Oct 13, 2009
La Porte, Indiana
Alright, this is a very confusing one - decided to post it since I can't find a lick of information on it.

I pulled this head from a Jasper rebuilt motor last year, it had 130k on it - 30k on the rebuild. The bottom end was in ok shape but the head looked VERY clean...so I kept it around. This years build I used the head for my 6 bolt, had it drilled for head studs, cleaned up by the machinist. I did my valve springs/retainers/lifters etcetc and I also got a set of SIM 275 cams. All good right? Nope.

First start I had this obnoxious knock in the head...I quickly narrowed it down to the intake cam. I figured since they were regrinds there was something that could've gone down hill with that. You could clearly see the amount of play the cams had lateral and axial in the journals. You could infact see through the journals at an angle. Here is what I'm talking about:

YouTube - MVI 0186

I decided to then try the stock cam to narrow down what it could be...stock cam fits great....

YouTube - Stock Cam

So it's gotta be the regrind right? Nope...I mic'd those according to the specs Delta gave SIM, they are solid and as it turns out - my head is...oversized? Which means I have oversized stock cams...? How is that possible? I've never heard of that...I mic'd the stock cams and they are both 'larger' than OEM spec.

...with that being said, what course of action should I take? Get my head fixed? Send this 'stock cams' to Delta for a regrind to fit my head? Get a bare 2g head somewhere? Nothing is easy with this car I swear :(
 
SIM 275 cams measured 1.022 ~ 1.023 - given 0.001 for inaccuracy of the digital caliper they measured dead onto spec of 1.023in. I popped 2 cam caps off and slide the caliper on the 'stock' cams and got 1.050 and 1.051in...WTF is right. I plan to measure them once I figure out the most cost effective method of using these 275s, just kinda flat broke at the moment.

Want to know the irony? Allen at SIM hooked me up with a deal on these 275s, I traded him 3x 2g heads in various condition for them ROFL

DSM is never easy I swear it.
 
the only other time i have see that is, when the caps that hold the cams down were mixed up from another head....ended up machine both heads and getting new cams made. give marco a call he had a guy who can do it
 
SIM 275 cams measured 1.022 ~ 1.023 - given 0.001 for inaccuracy of the digital caliper they measured dead onto spec of 1.023in. I popped 2 cam caps off and slide the caliper on the 'stock' cams and got 1.050 and 1.051in...WTF is right. I plan to measure them once I figure out the most cost effective method of using these 275s, just kinda flat broke at the moment.

Want to know the irony? Allen at SIM hooked me up with a deal on these 275s, I traded him 3x 2g heads in various condition for them ROFL

DSM is never easy I swear it.

We have never seen this but have been working with you to get to the bottom of this. If you need one of your heads back let us know i'm sure there is something we can work out.
 
We have never seen this but have been working with you to get to the bottom of this. If you need one of your heads back let us know i'm sure there is something we can work out.

It would be cool one way or another, I'm in no way saying anything negative about SIM - you guys have been nothing but helpful through this ordeal and I mean no harm towards your company, I've been convincing/sending all my friends down here to you guys rofl. I gotta head up there and grab the hood off John's parts car sometime this week - I'll give ya a call tomorrow and we can work something out :hellyeah:
 
i would call jasper and ask them. wouldnt surprise me at all if they (do or did) sell oversize cams (bearing journals) to save scrapping heads....your best option is to get another head.... bummer
 
i would call jasper and ask them. wouldnt surprise me at all if they (do or did) sell oversize cams (bearing journals) to save scrapping heads....your best option is to get another head.... bummer

That's what I was thinking. I still got the warranty number for the motor it came off of...they should be able to look it up. As I said earlier, I traded 3 heads for the cams & TofastForU_99 said we can work something out for getting one of them back - either way it will all play out good.

so your 275 are under spec or the oem are over size? what did they factory Manuel say about the clearances?

OEM spec is 1.023in, the SIM 275s are exactly that - they are fine. It's the strange recyling of my head & stock cams that are oversized. I measured 1.050in on the stock cams.
 
Jasper Line bored a damaged head to salvage it, then had cams welded and ground to fit.

We do it all the time on rare heads. we just made custom mains for a 1926 chevy this morning.
Stock heads not the best thing to do, but a fully race prepped head cheap fix vs. paying out the ass for a ton of port work.

my $ .02 worth
 
Take that head and cams off and scrap them all to rid yourself and anyone else of this possible headache later on.

You can find good rebuilt OEM heads in the $300 range which haven't been butchered and had spray-welded cams installed.
 
So his head is no good?? or is it the cams?? I wanted to buy those cams but i dont think i am any more..
 
So his head is no good?? or is it the cams?? I wanted to buy those cams but i dont think i am any more..

Seriously, how is this difficult to understand? :confused:

There's nothing wrong with SIMs cams, the head was bored and a cam with larger than stock journals was installed. OP put a cam with normal journals in it.
 
Seriously, how is this difficult to understand? :confused:

There's nothing wrong with SIMs cams, the head was bored and a cam with larger than stock journals was installed. OP put a cam with normal journals in it.

What he said :thumb:

I got a bare head from the guys at SIM and swapped my valves/springs/retainers/lifters over, stuck the 275s in and everything was PERFECT :hellyeah: I love how these cams sound, very aggressive sounding. Power band has a noticeable shift to the higher RPMs compared to stockers. Can't wait to get my HX40 in and see how things turn out
 
Seriously, how is this difficult to understand? :confused:

There's nothing wrong with SIMs cams, the head was bored and a cam with larger than stock journals was installed. OP put a cam with normal journals in it.

ahh... makes sense :aha:
 
Good to hear they helped ya out, Good customer service is KEY, and S.I.M. does great
!
 
I was gonna say that I have these same exact cams in my head and I have zero play in them. Plus S.I.M. has awesome customer service and they had my cams to me faster than I thought was gonna be even remotely possible.

How is your idle & vac?
 
Ahh...well for reference, I'm seeing about -7 ~ -9 vac at 950rpm. I had to raise my idle by 200 to make it more bare-able. When the rpms would dip low the brake pedal would become hard.
 
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