'87 S4 Timing Death
05-20-2016, 09:15 AM
#46
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Thread Starter
Unlikely the belt was manufactured too long, but not impossible.
More likely the heads were milled excessively. The car did run like a bat out of hell...maybe it has a little bit more than stock compression.
More likely the heads were milled excessively. The car did run like a bat out of hell...maybe it has a little bit more than stock compression.
05-20-2016, 10:22 AM
#49
Pro
Thread Starter
In February, 2005, at 197,920 miles, Cignatta Motor Works of Abindgon, MD (I do not know of this shop) found "NO OIL" and "Cracked left head at oil passage" and replaced both cylinder heads with "used" along with timing belt, water pump (presumably new, but who knows), "2 rollers" and "chain guides" (this is all hand-written, with the parts either rolled into the $2800 labor cost (to avoid the sales tax on parts in MD), or heads and other parts were provided by the customer (doesn't say). Invoice is $2,979.47 with only $138 in parts and $7.97 in tax. This included an oil and filter change with Castrol 20W50 (10 units billed at $21.50 total!) and $12 worth of fuel.
05-20-2016, 10:23 AM
#50
Pro
Thread Starter
There is no mention of the heads being machined, nor any sublet to a machine shop...but then again the used heads themselves are not invoiced separately and could have been provided by the customer (machined or not).
05-20-2016, 10:27 AM
#51
Pro
Thread Starter
I installed new (aftermarket) cam sprockets (from Roger) and a genuine Porsche oil pump gear, but I cannot find any record of a new crank gear. There was a lot of discussion of worn cam sprockets as well as oil pump gears, so I decided not to cut corners and did them all. Except the crank gear. Which looked fine. To a Saab tech. And then I deleted the little rollers next to it. Because they weigh so much and look so ugly.
05-20-2016, 10:43 AM
#55
Shameful Thread Killer
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The heads will come off your car without engine removal if you want to have them fixed. However, I understand ex valves are getting scarce and pricey. Typically a valve crash doesn't result in piston damage but you won't know without a borescope or head removal.
Root cause on the jump is gonna be difficult but that 'perfect storm' of contributing factors sounds likely. The tensioner is too far extended by the guy that designed it, so beyond that, I'm done.
Maybe string a bone stock Gates belt before pulling the heads, and compare the tensioner extension? Would only take an hour of labor and a belt from Roger at this point. Your crank gear looks fine to me from the pic.
Root cause on the jump is gonna be difficult but that 'perfect storm' of contributing factors sounds likely. The tensioner is too far extended by the guy that designed it, so beyond that, I'm done.
Maybe string a bone stock Gates belt before pulling the heads, and compare the tensioner extension? Would only take an hour of labor and a belt from Roger at this point. Your crank gear looks fine to me from the pic.
05-20-2016, 10:45 AM
#56
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The racing belts and the stock belts are formed on the same tool. One big belt 108" long and then cut into 1" individual belts.
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
05-20-2016, 10:49 AM
#57
Nordschleife Master
Roger, interested in your view: Do you see any reason to be concerned about the combination of Porkensioner (with new bracket) and the Gates Racing belt?
05-20-2016, 10:55 AM
#58
Pro
Thread Starter
Water pump (new Porsche) is not seized.
I can put a 8mm allen in the tensioner roller and compress the Audi tensioner...it is not stuck/seized out. The bolt for the roller is tight.
I can put a 8mm allen in the tensioner roller and compress the Audi tensioner...it is not stuck/seized out. The bolt for the roller is tight.
05-20-2016, 11:59 AM
#60
Rennlist Member
As for the machined heads theory, the WSM indicates that the machining limit is 0.4 mm +- 0.1. So let's say they were machined to the limit and the previous tech didn't use the thicker head gasket. Based on the belt routing, this would give approx 2 mm extra belt to soak up (0.5 mm x 4). The PK tensioner arm rotates around a pivot point so I am not certain what 2 mm belt slack would equate to in terms of piston extension. Maybe Ken could chime in on that one.