stock valve timing

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monkey wrench
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Joined: Sat Aug 04, 2018 3:30 pm

stock valve timing

Post by monkey wrench » Sat Aug 04, 2018 4:19 pm

I know it must be on here somewhere but I've searched and can't find it anywhere. I have just finished a rebuild on a 69 ghia and I installed the customer's "Classis Line" new camshaft, along with cam followers and all the other rebuild stuff that's not relevant to this question. Upon firing it up, it will barely idle at 850, it lopes like it's got a cam but "Classic Line doesn't even offer a performance cam so it should be stock. I'm no newbie to VW's having worked at several dealerships and my own shops for many years, but this one's got me stumped. I have checked (and re-checked) all the usual, intake leaks, ignition components, cam/crank alignment, exhaust, and I'm pretty much left with a bad cam, unlikely as that seems. I can put a degree wheel on it and check valve timing, but I need to know what stock specs are and I can't find them anywhere. I'm talking about intake open, closed, exhaust open, closed, and I can figure duration from there. I just want to make sure what I've got before I tear this thing down again. If you have the specs or know where to find them I'd greatly appreciate it!

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raygreenwood
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Re: stock valve timing

Post by raygreenwood » Sat Aug 04, 2018 4:55 pm

I know the Haynes manual for type 4 cars 411/412 has those specs...so does Haynes for 914. The Haynes for bay bus with type 4 engine...oddly....does not have these. Its possible the Haynes for type 1 or type 3 has them.

It may be because there are too many cam versions out there from the factory over the years. I will look in the books I have. Ray

monkey wrench
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Re: stock valve timing

Post by monkey wrench » Sat Aug 04, 2018 6:32 pm

Thanks Ray. It's not in the Without Guesswork, or the Bentley.
Roger

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jsturtlebuggy
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Re: stock valve timing

Post by jsturtlebuggy » Sun Aug 05, 2018 10:37 am

From the book "How to HotRod Volkswagen Engines" by Bill Fisher, stock camshaft specs are
intake 7.5-37, exhaust 44.5-4. Lift intake .332",exhaust .310" Duration intake 224, exhaust 228 degrees
Checked at .040"
I have found this is fairly close to all the stock cams I checked over the years.
The book was published in 1970 and also shows the cam specs from 1200cc engines too.
Joseph

monkey wrench
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Re: stock valve timing

Post by monkey wrench » Sun Aug 05, 2018 1:51 pm

Thank you Joseph. Exactly what I was looking for.
Roger

monkey wrench
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Re: stock valve timing

Post by monkey wrench » Sun Aug 05, 2018 4:28 pm

Joseph/Ray
I appear to need some remedial tutoring. I wanted to make sure all my measurements were accurate and made sense so I set up a case half in the engine stand and dropped a used crank and cam into it. I set up a dial gauge (had to jury rig a holder for it) and measured two of the lobes, one intake and one exhaust. I had difficulty getting good repeatable results, with discrepancies of up to 10 degrees, probably due to the jury rigged dial gauge setup, so you have to take that into account, but most of my readings are nowhere close to those from Bill Fisher's book. My readings (all taken at .040" of lift) were as follows:

intake open: 6 degrees ATDC
intake close 80 degrees ABDC

exhaust open 55 degrees BBDC
exhaust close 20 degrees ATDC

Now admittedly, I'm not quite sure how to read those specs from Fisher's book, whether they are before or after top or bottom dead center, but anyway that I look at them, mine don't come close, even figuring in the 10 degree or so variance. I have literally been working on VW's since 1966 but I am certainly no expert when it comes to camshafts. (Probably very little else, either) I have always re-used them if they showed little wear, or replaced them if they looked worn. I was, for the most part, not building racing engines. Anyway, not trying to write a book here, just looking for some answers. Your input greatly appreciated.
Roger

monkey wrench
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Re: stock valve timing

Post by monkey wrench » Sun Aug 05, 2018 10:46 pm

I finally found the specs posted on here in 2010 that made sense to me.

"Type 1: 1300-1600:
Inlet opens: 7.5 deg BTDC
Inlet closes: 37 deg ABDC
Exh opens: 44.5 deg BBDC
Exh closes: 4 deg ATDC.
This is VW specs, measured at 1mm lift."
I measured the rebuilt engine at the adjusting screw and used .044 instead of .040 to account for the 1.1:1 rockers. Measurements were repeatable and I think fairly accurate. This is what I got:
intake opens: 27 deg BTDC
intake closes 58 deg ABDC
exhaust opens 64 deg BBDC
exhaust closes 29 deg ATDC

I didn't measure lift but this cam has way more duration than stock. Can any of you cam savvy guys tell me what you think this cam is supposed to perform like, and could it be the cause of my idle problem? (Also getting backfire on decel, that might be exhaust leak though.) Hate to tear it back down, but have to solve it.
Thanks for the help.
Roger

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raygreenwood
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Re: stock valve timing

Post by raygreenwood » Sun Aug 12, 2018 2:23 pm

monkey wrench wrote:
Sun Aug 05, 2018 10:46 pm
I finally found the specs posted on here in 2010 that made sense to me.

"Type 1: 1300-1600:
Inlet opens: 7.5 deg BTDC
Inlet closes: 37 deg ABDC
Exh opens: 44.5 deg BBDC
Exh closes: 4 deg ATDC.
This is VW specs, measured at 1mm lift."
I measured the rebuilt engine at the adjusting screw and used .044 instead of .040 to account for the 1.1:1 rockers. Measurements were repeatable and I think fairly accurate. This is what I got:
intake opens: 27 deg BTDC
intake closes 58 deg ABDC
exhaust opens 64 deg BBDC
exhaust closes 29 deg ATDC

I didn't measure lift but this cam has way more duration than stock. Can any of you cam savvy guys tell me what you think this cam is supposed to perform like, and could it be the cause of my idle problem? (Also getting backfire on decel, that might be exhaust leak though.) Hate to tear it back down, but have to solve it.
Thanks for the help.
Roger
Make a note.....do you notice that each of those measurements you took...are almost exactly 20* off (give or take) from what VW advertised? :wink:

How much more duration than stock does the cam have? If its 20* more...you know where that extra 20* in each measurement came from. Ray

monkey wrench
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Re: stock valve timing

Post by monkey wrench » Mon Aug 13, 2018 9:33 pm

Ray, I think you are right on. I tore it back down and remeasured everything directly at the cam, at .039 lift (1 mm) and at .050. Here's what I got:

STOCK VW SPECS
in /open in/close duration lift ex/open ex/close duration lift overlap
0.039 7.5 BTDC 37 ABDC 225 44.5 BBDC 4 ATDC 229 12
0.050 214 214

CLASSIC LINE CAM
in /open in/close duration lift ex/open ex/close duration lift overlap
0.039 30 BTDC 68 ABDC 278 0.364 65 BBDC 35 ATDC 280 0.379 65
0.050 24 BTDC 55 ABDC 259 0.364 59 BBDC 25 ATDC 264 0.379 49

If the stock cam specs are accurate then this cam is nowhere near stock. I'm waiting for the reground cam to get here, then I'll measure it before I button it up and try it again.
Roger
ps: I contacted Classic Line over a week ago and asked for their specs on the cam, but they never got back to me. FWIW, I'd stay away from their stuff.

monkey wrench
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Re: stock valve timing

Post by monkey wrench » Fri Aug 17, 2018 11:52 am

Should have just gone with my hunch. I replaced the cam with a reground stock cam and the engine now runs as it should, and idles perfectly. Just re-affirming why I hate aftermarket VW parts! Hope this thread helps someone else on down the road.

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