engine timing dilema - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Painter D · 12-28-2007, 02:35 PM

ok guys here goes, i recently installed a complete top end kit from trick flow on my sbc 355. it came with alum. heads a 494 lift cam, timing set roller rockers the whole 9 yards . anyways heres my issue, i have to set the timing at 30 degrees at idle, at the crank to get it to run the best. so when i accelerate my distributor advances it another 22 degrees so if im thinking correctly thats 52 degrees total timing. from what i hear thats way too much. when i try to set it any lower at the crank it backfires up through the carb. so heres my question if it runs good, and if it starts good is it going to be ok to leave it at this setting? everyone ive talked to scratches their head and says,"thats weird". any help would be great.

**WorkinLonghorn** · 12-28-2007, 03:01 PM

I have to do about the same thing to mine and I just figured the timing marks are wrong,maybe the balancer outer ring slipped or something. So I just timed it so that it still starts when hot,and just retarded from where it knocks on a hot day. Did you replace the balancer on yours?

Painter D · 12-28-2007, 03:15 PM

no i did not replace the balancer ,but thats very interesting about the outer ring moving

Evans · 12-28-2007, 03:53 PM

maybe off a tooth when you dropped the dizzy in ???

redhead69 · 12-28-2007, 06:09 PM

Did you plug the vac advance when checking? If its advanced too much the motor will act like its kicking back and real hard to get it to roll over upon start up.. find that point and back it off a little.. then drive and tune per ping method (same thing workinglonghorn's saying)

Jtrux · 12-28-2007, 06:14 PM

I agree that the marks might be wrong but if it ran before doing those things then I don't see why it wouldn't work now.

piecesparts · 12-28-2007, 06:46 PM

I would definitely RE-approach your timing. FIRST, did you set the timing with the vacuum hose removed from the distributor? (I am not saying you did wrong--just checking know how here) Second, you apparently set the timing with an ADVANCE type timing light to get the 33 degrees. What you are shooting for here is a TOTAL advance of around 35 degrees. Which when you disconnect the vacuum hose the initial timing will settle in around 15 to 22 degrees on the timing marks. You also want to set this timing with the engine RPMS where the distributor is at a speed to be fully advanced for the setting of TOTAL advance timing. That is where I would start.

SCOTI · 12-28-2007, 07:09 PM

If it's not 'pinging' real bad on acceleration I would say it's not really @ 52° timing.

Vacuum hose off, initial timing between 12~16°, then about 36° total timing. The alum heads might allow for a little more but it shouldn't need it. If you need help, let me know. I've done 1 or 2 of these . . .....

hotrod 80 · 12-28-2007, 09:10 PM

Evans got it right , your a tooth off .

Also my 355 likes 38* total all in by 2900-3000.

bhunt31 · 12-28-2007, 10:19 PM

Quote:

Originally Posted by 69chevyshort

ok guys here goes, i recently installed a complete top end kit from trick flow on my sbc 355. it came with alum. heads a 494 lift cam, timing set roller rockers the whole 9 yards . anyways heres my issue, i have to set the timing at 30 degrees at idle, at the crank to get it to run the best. so when i accelerate my distributor advances it another 22 degrees so if im thinking correctly thats 52 degrees total timing. from what i hear thats way too much. when i try to set it any lower at the crank it backfires up through the carb. so heres my question if it runs good, and if it starts good is it going to be ok to leave it at this setting? everyone ive talked to scratches their head and says,"thats weird". any help would be great.

I 100% agree with 12* no vacuum, 32 total advance. Outer rings have a bad habit of moving on hubs. If you don't mind paying the extra, get a 1 piece damper like a Vibratec. I've heard of guys picking up an additional 10hp on a decently built SBC just by using that damper.

Painter D · 12-29-2007, 03:04 PM

well i dont know whats changed since yesterday but now i got it down to 17deg at the crank with a vacumed advance total of 39deg(distributor kicks in 22deg) and it still runs great and starts easy. i also found out that my dist. has an adjustment to change the amount of advance, do i want to leave it all the way open so it will advance the full 22deg. or try to back some out of the dist. im also having issues with the temperature. i have tried 3 different thermostats with bad results. the best thermo. so far is a 160deg. but the temp will stabilize at 180deg. which is fine, but when i take off driving it will rise rapidly to about 220 sometimes 230 and then start to slowly go down. any ideas why this is? also heres a quick rundown of everything ihave under the hood :: sbc355 trick flow alum 195 heads, comp 480/494 lift cam, air gap intake ,holley 675 street avenger, new water pump, new 4 core radiator, corvette elec. fan. any info on how to keep this stuff at a stable cool temp would be great. OH YEAH i also shaved and painted the firewall while i had the engine out. just a little FYI.

bhunt31 · 12-29-2007, 03:12 PM

Quote:

Originally Posted by 69chevyshort

well i dont know whats changed since yesterday but now i got it down to 17deg at the crank with a vacumed advance total of 39deg(distributor kicks in 22deg) and it still runs great and starts easy. i also found out that my dist. has an adjustment to change the amount of advance, do i want to leave it all the way open so it will advance the full 22deg. or try to back some out of the dist. im also having issues with the temperature. i have tried 3 different thermostats with bad results. the best thermo. so far is a 160deg. but the temp will stabilize at 180deg. which is fine, but when i take off driving it will rise rapidly to about 220 sometimes 230 and then start to slowly go down. any ideas why this is? also heres a quick rundown of everything ihave under the hood :: sbc355 trick flow alum 195 heads, comp 480/494 lift cam, air gap intake ,holley 675 street avenger, new water pump, new 4 core radiator, corvette elec. fan. any info on how to keep this stuff at a stable cool temp would be great. OH YEAH i also shaved and painted the firewall while i had the engine out. just a little FYI.

are you sure it's actually getting that hot and it's not just the guage giving a false reading? I've never seen a SBC with a 4 core radiator get hot, especially full of coolant. I have a 4 core diesel radiator in my 84 and I can run it a gallon low on coolant and still not have a problem with heat.

Painter D · 12-29-2007, 03:14 PM

i guess anythings possible on the guage. its a simple mechanical guage,( no sending unit)

bhunt31 · 12-29-2007, 03:14 PM

try to back it down to about 15* and run with it. It should top out at around 37* and that should be fine with that cam.

bhunt31 · 12-29-2007, 03:16 PM

I'd try to pick up a new guage from Autozone or somewhere and stick it in there and see what it says. It just doesn't make sense that a truck would get hot like that with a 4 core in it. You're not running anything crazy with the belt routing that would've reversed the water pump flow direction, are you?

Painter D · 12-29-2007, 03:16 PM

when i put it at 15 it backfires up through the carb

bhunt31 · 12-29-2007, 03:17 PM

set it back up around 18-20 then, your outer ring has most likely moved on your balancer.

Painter D · 12-29-2007, 03:19 PM

no crazy belts here. the guage i have is from autozone and just by chance ihave a spare brand new temp guage laying around , ill try it tomorrow .

Painter D · 12-29-2007, 03:24 PM

i also went to autozone today and had them pull a new balancer so i could compare the key way and the timing marks position on a new one , so i could come home today and compare mine to it. it seemed to be in the same spot, just eyeballed it though.

bhunt31 · 12-29-2007, 03:31 PM

Quote:

Originally Posted by 69chevyshort

i also went to autozone today and had them pull a new balancer so i could compare the key way and the timing marks position on a new one , so i could come home today and compare mine to it. it seemed to be in the same spot, just eyeballed it though.

to be 5* off it only has to move a fraction of an inch.

haysonj · 12-29-2007, 03:58 PM

Just a thought but did you degree the cam when you installed it sprocket marks can be off. also on the temp if you drill a 1/8 in hole in the thermostat it will stop that sudden rise in temp

Painter D · 12-29-2007, 04:43 PM

1/8 hole you say ,ill try that tomorrow as well ,thanks

jamon8 · 12-30-2007, 04:09 AM

what kind of fan are you running-clutch could be going out

preasure test the radiator cap and cooling system

drilling that hole in the termostat will help also

smoky02 · 12-30-2007, 04:38 AM

I had a 327 in my truck and was having the exact same problem...I was only running vortec heads and not a set of aluminum, but I did have the 4 core and clutch fan...and it always ran hot when I had the timing turned up to where it ran best...but when I turned the timing down a little bit it would stay around 190 and not go higher (this is with a 160thermostat by the way). But I had a bunch of problems I didn't know about...my crank was eating up the bearings, and a few valves in my heads were bent. Solution...I built a different motor...LOL...and got the valves worked at a machine shop...don't know if this will help, but that was just my situation

Painter D · 12-30-2007, 03:18 PM

well iguess the hole i drilled fixed it, i also BURPED the system a little more , and i got a few more air bubbles to come out. as far as the temp is concerned anyway. as for the timing it is still set at 39 deg total timing (w/22 deg vac. adv.) it cant go any lower without backfiring through the carb.

12-28-2007, 02:35 PM	#1
Painter D Registered User Join Date: Jun 2007 Location: DFW (Forney) Posts: 1,529	engine timing dilema ok guys here goes, i recently installed a complete top end kit from trick flow on my sbc 355. it came with alum. heads a 494 lift cam, timing set roller rockers the whole 9 yards . anyways heres my issue, i have to set the timing at 30 degrees at idle, at the crank to get it to run the best. so when i accelerate my distributor advances it another 22 degrees so if im thinking correctly thats 52 degrees total timing. from what i hear thats way too much. when i try to set it any lower at the crank it backfires up through the carb. so heres my question if it runs good, and if it starts good is it going to be ok to leave it at this setting? everyone ive talked to scratches their head and says,"thats weird". any help would be great.

12-28-2007, 03:01 PM	#2
WorkinLonghorn Senior Member Join Date: Dec 2006 Location: Studio City, Calif. Posts: 2,886	Re: engine timing dilema I have to do about the same thing to mine and I just figured the timing marks are wrong,maybe the balancer outer ring slipped or something. So I just timed it so that it still starts when hot,and just retarded from where it knocks on a hot day. Did you replace the balancer on yours? __________________ '69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, stereo speakers, 2nd owner, Work-Truck supreme.

12-28-2007, 03:15 PM	#3
Painter D Registered User Join Date: Jun 2007 Location: DFW (Forney) Posts: 1,529	Re: engine timing dilema no i did not replace the balancer ,but thats very interesting about the outer ring moving

12-28-2007, 03:53 PM	#4
Evans Registered User Join Date: Feb 2007 Location: Dallastown , Pa Posts: 261	Re: engine timing dilema maybe off a tooth when you dropped the dizzy in ???

12-28-2007, 06:09 PM	#5
redhead69 fugedaboutit Join Date: Mar 2005 Location: Gresham, OR Posts: 832	Re: engine timing dilema Did you plug the vac advance when checking? If its advanced too much the motor will act like its kicking back and real hard to get it to roll over upon start up.. find that point and back it off a little.. then drive and tune per ping method (same thing workinglonghorn's saying) __________________ Currently truckless

12-28-2007, 06:14 PM	#6
Jtrux I'm a poor spectator Join Date: Aug 2006 Location: San Antonio, Tx Posts: 2,287	Re: engine timing dilema I agree that the marks might be wrong but if it ran before doing those things then I don't see why it wouldn't work now. __________________ 2006 Jeep Unlimited IMPACT ORANGE 1993 Chevy 2500 4x4 ExCab LWB 454/NV4500 Tow rig 1977 Ford F100 2x4 LWB 1st truck I owned, still have it!!! 1979 Ford F150 4x4 SWB Built Ford Tough!!! 1971 Chevy Blazer 350 / SM465 / NP205 UNDER CONSTRUCTION Soon to have a LQ4 6.0!!!

12-28-2007, 06:46 PM	#7
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: engine timing dilema I would definitely RE-approach your timing. FIRST, did you set the timing with the vacuum hose removed from the distributor? (I am not saying you did wrong--just checking know how here) Second, you apparently set the timing with an ADVANCE type timing light to get the 33 degrees. What you are shooting for here is a TOTAL advance of around 35 degrees. Which when you disconnect the vacuum hose the initial timing will settle in around 15 to 22 degrees on the timing marks. You also want to set this timing with the engine RPMS where the distributor is at a speed to be fully advanced for the setting of TOTAL advance timing. That is where I would start.

12-28-2007, 07:09 PM	#8
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,071	Re: engine timing dilema If it's not 'pinging' real bad on acceleration I would say it's not really @ 52° timing. Vacuum hose off, initial timing between 12~16°, then about 36° total timing. The alum heads might allow for a little more but it shouldn't need it. If you need help, let me know. I've done 1 or 2 of these . . ..... __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

12-28-2007, 09:10 PM	#9
hotrod 80 mini truck racer Join Date: Aug 2006 Location: Baytown , texas Posts: 3,010	Re: engine timing dilema Evans got it right , your a tooth off . Also my 355 likes 38* total all in by 2900-3000. Last edited by hotrod 80; 12-28-2007 at 09:14 PM.

12-29-2007, 03:04 PM	#11
Painter D Registered User Join Date: Jun 2007 Location: DFW (Forney) Posts: 1,529	Re: engine timing dilema well i dont know whats changed since yesterday but now i got it down to 17deg at the crank with a vacumed advance total of 39deg(distributor kicks in 22deg) and it still runs great and starts easy. i also found out that my dist. has an adjustment to change the amount of advance, do i want to leave it all the way open so it will advance the full 22deg. or try to back some out of the dist. im also having issues with the temperature. i have tried 3 different thermostats with bad results. the best thermo. so far is a 160deg. but the temp will stabilize at 180deg. which is fine, but when i take off driving it will rise rapidly to about 220 sometimes 230 and then start to slowly go down. any ideas why this is? also heres a quick rundown of everything ihave under the hood :: sbc355 trick flow alum 195 heads, comp 480/494 lift cam, air gap intake ,holley 675 street avenger, new water pump, new 4 core radiator, corvette elec. fan. any info on how to keep this stuff at a stable cool temp would be great. OH YEAH i also shaved and painted the firewall while i had the engine out. just a little FYI.

12-29-2007, 03:14 PM	#13
Painter D Registered User Join Date: Jun 2007 Location: DFW (Forney) Posts: 1,529	Re: engine timing dilema i guess anythings possible on the guage. its a simple mechanical guage,( no sending unit)

12-29-2007, 03:14 PM	#14
bhunt31 krazy hillbilly from Kentucky Join Date: Feb 2007 Location: Paris, IL Posts: 121	Re: engine timing dilema try to back it down to about 15* and run with it. It should top out at around 37* and that should be fine with that cam. __________________ 1969 Chevy CST/10 "Old School lives and breathes in the heart of a chosen few " 1984 Chevy C10 Silverado "Life, Liberty, and Ford's Pursuit of Chevy taillights" You say "Obsessed with my trucks" like it's a bad thing

12-29-2007, 03:16 PM	#15
bhunt31 krazy hillbilly from Kentucky Join Date: Feb 2007 Location: Paris, IL Posts: 121	Re: engine timing dilema I'd try to pick up a new guage from Autozone or somewhere and stick it in there and see what it says. It just doesn't make sense that a truck would get hot like that with a 4 core in it. You're not running anything crazy with the belt routing that would've reversed the water pump flow direction, are you? __________________ 1969 Chevy CST/10 "Old School lives and breathes in the heart of a chosen few " 1984 Chevy C10 Silverado "Life, Liberty, and Ford's Pursuit of Chevy taillights" You say "Obsessed with my trucks" like it's a bad thing

12-29-2007, 03:16 PM	#16
Painter D Registered User Join Date: Jun 2007 Location: DFW (Forney) Posts: 1,529	Re: engine timing dilema when i put it at 15 it backfires up through the carb

12-29-2007, 03:17 PM	#17
bhunt31 krazy hillbilly from Kentucky Join Date: Feb 2007 Location: Paris, IL Posts: 121	Re: engine timing dilema set it back up around 18-20 then, your outer ring has most likely moved on your balancer. __________________ 1969 Chevy CST/10 "Old School lives and breathes in the heart of a chosen few " 1984 Chevy C10 Silverado "Life, Liberty, and Ford's Pursuit of Chevy taillights" You say "Obsessed with my trucks" like it's a bad thing



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12-29-2007, 03:19 PM	#18
Painter D Registered User Join Date: Jun 2007 Location: DFW (Forney) Posts: 1,529	Re: engine timing dilema no crazy belts here. the guage i have is from autozone and just by chance ihave a spare brand new temp guage laying around , ill try it tomorrow .

12-29-2007, 03:24 PM	#19
Painter D Registered User Join Date: Jun 2007 Location: DFW (Forney) Posts: 1,529	Re: engine timing dilema i also went to autozone today and had them pull a new balancer so i could compare the key way and the timing marks position on a new one , so i could come home today and compare mine to it. it seemed to be in the same spot, just eyeballed it though.

12-29-2007, 03:58 PM	#21
haysonj Registered User Join Date: Dec 2007 Location: Santa Maria, Ca. Posts: 1,423	Re: engine timing dilema Just a thought but did you degree the cam when you installed it sprocket marks can be off. also on the temp if you drill a 1/8 in hole in the thermostat it will stop that sudden rise in temp __________________ 69 Chevy 4x4 383 Power

12-29-2007, 04:43 PM	#22
Painter D Registered User Join Date: Jun 2007 Location: DFW (Forney) Posts: 1,529	Re: engine timing dilema 1/8 hole you say ,ill try that tomorrow as well ,thanks

12-30-2007, 04:09 AM	#23
jamon8 Registered User Join Date: Apr 2006 Location: southern Il Posts: 335	Re: engine timing dilema what kind of fan are you running-clutch could be going out preasure test the radiator cap and cooling system drilling that hole in the termostat will help also

12-30-2007, 04:38 AM	#24
smoky02 Registered User Join Date: Oct 2003 Location: Sunny, Florida, some might call it South Alabama Posts: 834	Re: engine timing dilema I had a 327 in my truck and was having the exact same problem...I was only running vortec heads and not a set of aluminum, but I did have the 4 core and clutch fan...and it always ran hot when I had the timing turned up to where it ran best...but when I turned the timing down a little bit it would stay around 190 and not go higher (this is with a 160thermostat by the way). But I had a bunch of problems I didn't know about...my crank was eating up the bearings, and a few valves in my heads were bent. Solution...I built a different motor...LOL...and got the valves worked at a machine shop...don't know if this will help, but that was just my situation __________________ Just sold my C10...sad day... Looking for a 1972 Blazer to hopefully fill the hole in my heart.

12-30-2007, 03:18 PM	#25
Painter D Registered User Join Date: Jun 2007 Location: DFW (Forney) Posts: 1,529	Re: engine timing dilema well iguess the hole i drilled fixed it, i also BURPED the system a little more , and i got a few more air bubbles to come out. as far as the temp is concerned anyway. as for the timing it is still set at 39 deg total timing (w/22 deg vac. adv.) it cant go any lower without backfiring through the carb.

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