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Hi all,
Some details first, since those seem pretty important:
I've got a new 545 I finished building about a month ago in a 79 f250. It's a full forged 2-bolt bottom end in a D1VE block, SR-71 heads, big mutha thumpr hydr roller cam with roller rockers, hv oil pump & 12qt pan, weiand stealth intake, double roller timing chain, Cometic MLS head gaskets, edelbrock 110 gph mech fuel pump, stock Duraspark II dist with new gear, cap, and rotor, and an edelbrock 1913 800cfm carb.
I'm new to engine building so not completely ruling out and stupid mistakes, but a friend of mine who has a shop building engines helped me find the pushrod length and install the heads, rockers, cam, and timing chain, so I'm pretty sure thats all correct. I also had a shop recommended by him with lots of bbf experience assemble the short block, so also pretty confident in that. It runs about 170°, pulls 10" of vacuum at idle and has loads of power. No idea what the timing specs are as I need to take the alternator off to do that and haven't had time or weather to do so. It
Upon initial setup I had the plug wires on the dist set up 1, 2, 3, 4, 5 6, 7, 8 which I know isn't good but it only ran like that for maybe 10 minutes total?
The problems are:
1. It diesels when turned off. Messing with the distributor seems to affect it some, but it's gradually gotten worse to the point where it'll do it for 30+ seconds and I have to put it in gear and push the brake to make it stop.
2. It backfires through the carb when revved up too many times rapidly. Not every rev, but it's not hard to make it do it.
3. It starts backfiring at sustained high rpm. Anything over 4k, give or take a little depending on what gear you're in or if in nuetral, it'll start doing rapid small backfires out the exhaust. But if you rev it quick, you can hit 5,500 no problem. It's only sustained stuff it doesn't like. At least I think it's backfiring. I don't think it's knocking, at least.
4. It smells very rich and when you let off the gas it takes time for the rpms to drop. Idk if that's a timing problem or if the carb just needs tuned.
5. It hesitates a bit when stomping the gas, but replacing the vacuum advance module seemed to help some with that. It's not fully adjusted yet though.
Any suggestions/ideas?
Some details first, since those seem pretty important:
I've got a new 545 I finished building about a month ago in a 79 f250. It's a full forged 2-bolt bottom end in a D1VE block, SR-71 heads, big mutha thumpr hydr roller cam with roller rockers, hv oil pump & 12qt pan, weiand stealth intake, double roller timing chain, Cometic MLS head gaskets, edelbrock 110 gph mech fuel pump, stock Duraspark II dist with new gear, cap, and rotor, and an edelbrock 1913 800cfm carb.
I'm new to engine building so not completely ruling out and stupid mistakes, but a friend of mine who has a shop building engines helped me find the pushrod length and install the heads, rockers, cam, and timing chain, so I'm pretty sure thats all correct. I also had a shop recommended by him with lots of bbf experience assemble the short block, so also pretty confident in that. It runs about 170°, pulls 10" of vacuum at idle and has loads of power. No idea what the timing specs are as I need to take the alternator off to do that and haven't had time or weather to do so. It
Upon initial setup I had the plug wires on the dist set up 1, 2, 3, 4, 5 6, 7, 8 which I know isn't good but it only ran like that for maybe 10 minutes total?
The problems are:
1. It diesels when turned off. Messing with the distributor seems to affect it some, but it's gradually gotten worse to the point where it'll do it for 30+ seconds and I have to put it in gear and push the brake to make it stop.
2. It backfires through the carb when revved up too many times rapidly. Not every rev, but it's not hard to make it do it.
3. It starts backfiring at sustained high rpm. Anything over 4k, give or take a little depending on what gear you're in or if in nuetral, it'll start doing rapid small backfires out the exhaust. But if you rev it quick, you can hit 5,500 no problem. It's only sustained stuff it doesn't like. At least I think it's backfiring. I don't think it's knocking, at least.
4. It smells very rich and when you let off the gas it takes time for the rpms to drop. Idk if that's a timing problem or if the carb just needs tuned.
5. It hesitates a bit when stomping the gas, but replacing the vacuum advance module seemed to help some with that. It's not fully adjusted yet though.
Any suggestions/ideas?
