After discussing this build with my client, he sent me his largeport head, and his Crower cams.





Unpacked...





cam covers removed....





and fully disassembled, prior to getting cleaned, pressure checked, and tumbled





more to come.......

A closer look at the valves......

Once you get past the really bad one... do you see it?




The TVIS effect.... Valves 1, 4,5, and 8, the valves w/o the TVIS butterflies have far more build up.





... and this head has been serviced at least once before... head machined...


... and valve job??






more to come.....

from another forum wrote:Are those valve seats machined crookedly?

Why yes.... yes they are . And don't ask how they did it... cause I don't even know.....

This is just another reason to get the head properly rebuilt....


So, on to deburring the head, and I found this




simply amazing......................


Now, this is the cam card that came with my client's cams.....




anyone tell me what seems to be wrong???



More to come......

from another froum1 wrote:I'll venture an uneducated guess. A negative number for the exhaust valve closure, i.e. -8.0 BTDC. Perhaps a negative "before" degree reading equals "after"?

PS: Are you keeping the fishing line weight or returning it to the client?

from another forum2 wrote:The nomenclature is very strange to begin with and the visual aid isn't helping at all with the intake going full circle.

The duration @0.05 lift and the opening closing degrees don't add up for me. The intake calcutes to 212 but the exhaust ends up at 228. If I interpret the minus sign for the exhaust wrong I can get it to 212 but then there wouldn't be any overlap (on the contrary all valves would be closed for 8°). Also the ramp seems to be very slow/wide but that might just be me as I'm comparing it to Catcams which are known for a rather aggressive ramp angle.

I haven't wrapped my brain around engine related things for years and it's very late so I might be completely off

In this case it is 8 degrees BTDC, otherwise as "from another forum2" mentioned we would be @ 228 if it were after TDC. A few things to remember most of the mild cams will close the exhaust valve BTDC, or close to TDC, while still at a certain lift point (either .040"/1mm, or .050"), seat to seat the valve still usually closes after top dead center - dependent on cam timing.

agreed, their timing wheel/diagram doesn't help either......

As to comparing them to Cat cams - yes, the Crower are far more mild a ramp, and offer only a minimal lift increase (7.75mm lift) over stock cams. The Cat cams I typically recommend for mild builds are 212 @ .040" (likely around 208-210@.050"), but with 8mm lift. So the Cat cams are a tiny bit shorter in duration @, much shorter in duration overall, and offer more lift. The Crowers will twist a few hundred more rpm.


But while all that is pertinent, that wasn't what I was after.....


This is what I was focused on..... Crower had HOT clearances... something you just don't get, and the FSM only has a reference for.... AND the reference is looser then Crower's spec - possibly making clearances too tight on the Crower cams....







more to come.......

PS - didn't keep the weight....

I enjoy reading these posts.

I wish this forum was as active as it was back in the late 1990's.

Sepheroth86 wrote:I enjoy reading these posts.

I wish this forum was as active as it was back in the late 1990's.

Thank you.... I'm doing my part in keeping the forum alive.....

from another forum wrote:I seen the clearance thing but disregarded the 'hot' part entirely as the seemed in the ballpark for 'cold' - maybe another typo?

Have you tried contacting Crower - as there's some blurb about changed specs and stuff?

I called, and left a message, as well as emailing them. No answer.....

Then I got the brilliant idea of doing a search on their website.... bingo.

Some changes - clearances no longer specified hot, some absent info - TRD single springs are no longer available, so no spring listed. Timing wheel better... but still inaccurate, or at least it doesn't represent actual timing.



full size view - http://gallery.ostportworks.com/albums/userpics/10005/Cam_card_2021_complete~0.jpg



now 2 down.....




from a slightly different perspective




more to come.....

from another forum wrote:I know it's tedious but in my opinion you would be best off to measure it yourself - if they did change the specs at one point who knows what version you have in hand.

EDIT: as for the illustration it looks intended as an abstract and not to the actual degree as 8° ATDC isn't anywhere close to what is pictured in either of the two drawings

Agreed, I set clearances to .006" on the intake side, and .008" on the exhaust side.

As far as cam timing, that is in my client's hands - I did send him both cam cards - so he should be able to set them up.


From 3 down to 4 down.......





And off to the machine shop where that horrible valve job went away....




Once back in my hands, a quick re-assembly... and checking clearances....




A big swing is needed... 10 of 16 valves I can't get a clearance on.... so back to the shop to get them tipped - If you look to the far left you can see how much I had the intake valves tipped....


Now with clearances set - a set of faux cams is fitted to keep the shims/buckets in place during return shipping.