Few engine questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Nima · 08-14-2006, 12:49 AM

Hey everybody:
I have few general questions about engines:
1- If your vlave guides/sleeves are wide or loose, can you still perform engine compression test? If no, is there anyway to find out the condition of the block without pulling the engine out?
2- If timing chain slips, what will happen to engine? Let's say engine was in a good working condition before slipage.

The reason I am asking these questions is that my valve guide(s) in my current 350 engine are wide (I am sorry I don't know the terminology. I believe I have vaccume leak based on my vaccume gauge manual) and Now, I came cross a 1977 olds cutlass supreme with 350 engine which has slipped timing chain which I can buy for few hundred $$. Give me your tought please.

cableguy0 · 08-14-2006, 01:40 AM

both engines are probably completely worn out and due for a rebuild. it takes a lot of miles before a timing chain will actually slip. the olds 350 is not the same engine as the chevy 350. parts usually wear at the same rate. if the top end is worn out in an old engine the bottom end is likely not far behind.

QKENUF4U · 08-14-2006, 09:13 AM

sounds like i would stay with the motor you have now cause the bad timing chaing will cause way more problems if it does actually "SLIP" (bent valves when the pistons come up and hit them etc.)
so what makes you think its just the valves guides thats causing whatever problem you have ?

MrC1 · 08-14-2006, 10:57 AM

A slipped chain (if that's what really happened) is very uncommon and would probably take 150,000-200,000 miles of wear to get that much stretch in a chain. More likely, the engine had a plastic timing gear from the factory and due to heat cycles over the years, it fell apart.

Either way, it's very easy to bend valves and/or damage pistons if the timing chain isn't doing its job.

Worn valve guides or valve stem seals are typically diagnosed by small puffs of oil smoke when starting up from a light. If it smokes all the time, that's more likely worn/damaged piston rings.

08-14-2006, 12:49 AM	#1
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,179	Few engine questions Hey everybody: I have few general questions about engines: 1- If your vlave guides/sleeves are wide or loose, can you still perform engine compression test? If no, is there anyway to find out the condition of the block without pulling the engine out? 2- If timing chain slips, what will happen to engine? Let's say engine was in a good working condition before slipage. The reason I am asking these questions is that my valve guide(s) in my current 350 engine are wide (I am sorry I don't know the terminology. I believe I have vaccume leak based on my vaccume gauge manual) and Now, I came cross a 1977 olds cutlass supreme with 350 engine which has slipped timing chain which I can buy for few hundred $$. Give me your tought please. __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner

08-14-2006, 01:40 AM	#2
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	Re: Few engine questions both engines are probably completely worn out and due for a rebuild. it takes a lot of miles before a timing chain will actually slip. the olds 350 is not the same engine as the chevy 350. parts usually wear at the same rate. if the top end is worn out in an old engine the bottom end is likely not far behind. __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

08-14-2006, 09:13 AM	#3
QKENUF4U Senior Member Join Date: Jan 2005 Location: SUNNY WARM BIKE RIDING COTTONWOOD ARIZONA Posts: 2,097	Re: Few engine questions sounds like i would stay with the motor you have now cause the bad timing chaing will cause way more problems if it does actually "SLIP" (bent valves when the pistons come up and hit them etc.) so what makes you think its just the valves guides thats causing whatever problem you have ?

08-14-2006, 10:57 AM	#4
MrC1 Dork For Days Join Date: Aug 2005 Location: Dallas Posts: 407	Re: Few engine questions A slipped chain (if that's what really happened) is very uncommon and would probably take 150,000-200,000 miles of wear to get that much stretch in a chain. More likely, the engine had a plastic timing gear from the factory and due to heat cycles over the years, it fell apart. Either way, it's very easy to bend valves and/or damage pistons if the timing chain isn't doing its job. Worn valve guides or valve stem seals are typically diagnosed by small puffs of oil smoke when starting up from a light. If it smokes all the time, that's more likely worn/damaged piston rings. __________________ 1972 C20, 402/700R4 - My first classic truck, bought in September 2005. 85% transformed from "Farm" to "Cool" status! 1970 Dodge Challenger 440, 4sp (my other toy) 12.67 @ 117 MPH, with a pathetic 2.022 60' 2007 Dodge Charger SRT-8 2008 Cadillac CTS All-American garage, baby!



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