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Timing chain and gear set

  
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Timing chain and gear set

 
69GTOby 69GTOby
Guru | Posts: 1118 | Joined: 02/09
Posted: 10/02/09
08:11 AM

My engine is a 1970 YS code 400.  Did this engine come with nylon teeth timing gears?  Someone was telling me so and also that they are notorious for jumping teeth.  If mine jumped teeth that would explain why my engine hates anything lower than like 15* base timing.  It would also explain the rough idle and vibrating vac gauge since the ignition timing and valve timing would both be advanced.  Would jumping teeth cause poor lubrication to the heads and low oil pressure??

There's a nice Comp Cam double roller timing chain and gear set for like $55 calling me out.  
****
1969 GTO resto in progress. '76 350+.060, #13 heads, 9.2:1 CR, Lunati cam, Edelbrock Performer, 750 Holley, HEI, Ram Air manifolds, 2 1/2" exhaust. TH400 trans w/shift kit and 2400 stall.  235/60/15 front, 275/60/15 rear on Rally II 15X7s.  GM 12 bolt posi with 3.73's.

Pontiacman8 Pontiacman8
Moderator | Posts: 5779 | Joined: 02/08
Posted: 10/02/09
08:18 AM

I have never seen a timing set with nylon teeth on a Pontiac engine only chevy.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

Pontiacman8
Pontiacman8
Pontiacman8

69GTOby 69GTOby
Guru | Posts: 1118 | Joined: 02/09
Posted: 10/02/09
08:40 AM

Oh okay.  Apparently this guy did not know what he was talking about.  Could the engine still have jumped teeth?  If not, could the slack be excessive enough to cause these problems I described?  
****
1969 GTO resto in progress. '76 350+.060, #13 heads, 9.2:1 CR, Lunati cam, Edelbrock Performer, 750 Holley, HEI, Ram Air manifolds, 2 1/2" exhaust. TH400 trans w/shift kit and 2400 stall.  235/60/15 front, 275/60/15 rear on Rally II 15X7s.  GM 12 bolt posi with 3.73's.

Pontiacman8 Pontiacman8
Moderator | Posts: 5779 | Joined: 02/08
Posted: 10/02/09
09:31 AM

Yes
15 degrees is not high for the initial timing.
I doubt that the timing chain jumping a tooth would effect the oil pressure at all.
How many miles is on this engine?  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

Pontiacman8
Pontiacman8
Pontiacman8

69GTOby 69GTOby
Guru | Posts: 1118 | Joined: 02/09
Posted: 10/02/09
10:20 AM

Odo shows 53K miles, not sure of the accuracy of that.  Basically, I have no idea of the miles.  But, the engine is vary clean internally and has very good compression numbers and 6-10% leakage in all cylinders.  15 degrees is not high?  Lol the timing tag only goes to 12* and I think the spec is 10 or 12. ?  
****
1969 GTO resto in progress. '76 350+.060, #13 heads, 9.2:1 CR, Lunati cam, Edelbrock Performer, 750 Holley, HEI, Ram Air manifolds, 2 1/2" exhaust. TH400 trans w/shift kit and 2400 stall.  235/60/15 front, 275/60/15 rear on Rally II 15X7s.  GM 12 bolt posi with 3.73's.

Pontiacman8 Pontiacman8
Moderator | Posts: 5779 | Joined: 02/08
Posted: 10/02/09
11:06 AM

No 15 degrees is not too high.
The timing tag on mine goes to 16 and where I have my timing set the mark is pass that.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

Pontiacman8
Pontiacman8
Pontiacman8

flynryan flynryan
User | Posts: 151 | Joined: 01/09
Posted: 10/02/09
12:05 PM

16deg is a standard intitial timing setting on a Pontiac. Soulnds like the poor idle is a result of valve lash / preload being out, or poor carb tuning.

I have never seen any Pontiac ever jump teeth. Even with 200,000 miles, not even close to loose enouph.  

69GTOby 69GTOby
Guru | Posts: 1118 | Joined: 02/09
Posted: 10/02/09
03:40 PM

I have gotten so many mixed signals about the timing spec.  My '69 Pontiac manual says 10* and you're telling me 16*.  Not that I don't believe you all, in fact I take your word over the manual, it's just confusing.  

Why did Pontiac make initial timing 16* while the timing mark only goes to 12*?  Lol.  How do I set timing without any mark to line it up to?  
****
1969 GTO resto in progress. '76 350+.060, #13 heads, 9.2:1 CR, Lunati cam, Edelbrock Performer, 750 Holley, HEI, Ram Air manifolds, 2 1/2" exhaust. TH400 trans w/shift kit and 2400 stall.  235/60/15 front, 275/60/15 rear on Rally II 15X7s.  GM 12 bolt posi with 3.73's.

Pontiacman8 Pontiacman8
Moderator | Posts: 5779 | Joined: 02/08
Posted: 10/03/09
07:05 AM

Ya it depends on who you ask just because the factory called for 10* initial timing that does not mean that is were the engine will run best.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

Pontiacman8
Pontiacman8
Pontiacman8

65pmdgto1 65pmdgto1
Enthusiast | Posts: 510 | Joined: 12/07
Posted: 10/03/09
10:09 AM

Don't know what the altitude is where you live but you can add some timing for increased alitude. I forget the formula but at 5000 feet we would add 4-6 to the recomended factory spec for starters and up from there. Factory spec is always on the very conservative side. The gas is higher octane there too. Premium cat pee is 93 as opposed to the sea level 91 stuff.
Top end oiling is lifters or just added up wear through all bottom end. Don't bother with the $55 stuff go for the $100 one you'll appreicate the difference. The timing set Comp Cam "include" in their kits would be a good one to put on a rattle can rebuild of an old 326 not a performance build.  

Pontiacman8 Pontiacman8
Moderator | Posts: 5779 | Joined: 02/08
Posted: 10/03/09
10:20 AM

I use the competition speed pro on mine and I'm very satisfied with it it is around a $100 through Jeg's.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

Pontiacman8
Pontiacman8
Pontiacman8

69GTOby 69GTOby
Guru | Posts: 1118 | Joined: 02/09
Posted: 10/05/09
04:18 PM

Cool.  I'll go with a 100 dollar timing set for sure.

Maybe I should do the timing chain and gear set and also a cam a lifter set at the same time.  That way I can get some more power with the cam, eliminate any slack in the timing set, and also possibly solve the oiling issue provided that the lifters are the cause of the poor valve train oiling.  
****
1969 GTO resto in progress. '76 350+.060, #13 heads, 9.2:1 CR, Lunati cam, Edelbrock Performer, 750 Holley, HEI, Ram Air manifolds, 2 1/2" exhaust. TH400 trans w/shift kit and 2400 stall.  235/60/15 front, 275/60/15 rear on Rally II 15X7s.  GM 12 bolt posi with 3.73's.

gto66 gto66
Enthusiast | Posts: 488 | Joined: 11/08
Posted: 10/05/09
05:08 PM

YES it can and does unless changed after leaving factory.I just changed a cam gear on a 1970 YS 400 that had a nylon cover, the crank gear will be metal. Pontiac did this to cut down on noise. My 1970 YS 400 had set 14 years so I pulled heads to change head gaskets and valve seals. After having two 1966 WT 389's, 1967-400and 1971-455 and 1976-400 with this problem. The first time it stripped the nylon andI neglected to pull oil pan and clean it on dealer advice. 500 miles later oil pump screen became plugged and lost oil pressure.NOT GOOD!  

gto66 gto66
Enthusiast | Posts: 488 | Joined: 11/08
Posted: 10/05/09
05:12 PM

Second note the 66's were GTO, 67 was Firebird ,Other two were Grand Prix's  

69GTOby 69GTOby
Guru | Posts: 1118 | Joined: 02/09
Posted: 10/05/09
05:23 PM

I have a '70 YS 400 as well...  You mean these engines DO have nylon cam gear teeth, and they CAN and DO get stripped and slip???

"After having two 1966 WT 389's, 1967-400and 1971-455 and 1976-400 with this problem."  What problems were you having?  
****
1969 GTO resto in progress. '76 350+.060, #13 heads, 9.2:1 CR, Lunati cam, Edelbrock Performer, 750 Holley, HEI, Ram Air manifolds, 2 1/2" exhaust. TH400 trans w/shift kit and 2400 stall.  235/60/15 front, 275/60/15 rear on Rally II 15X7s.  GM 12 bolt posi with 3.73's.

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