bronc08
New Member
- Joined
- January 3, 2007
- Messages
- 5
- Reaction score
- 0
- City, State
- Saskatoon, Saskatchewan
- Year, Model & Trim Level
- 89 Bronco II
Here's the story. I'm swapping my BII over to a 4.0 and 5 speed out of a 91 Explorer.
The motor has 237,000 km and some lifter noise. I plan on doing new bearings, oil pump, seals, rings, gaskets, lifters, pushrods, rocker shafts, and a cam. I can still see factory cross hatching but there is a small ridge.
The gaskets will be felpro. Bearings are sealed power. I hear I should still use FORD lower intake, head gaskets, valve cover gaskets. Is this a good idea?
Machinist said the block is tapered 2.5 thou. Not out of round. He said that's on the upper limit. Haynes says the taper service limit is 0.010. The out of round limit is 1.5 thou and the service limit is 5 thou. There is no limit listed for the taper. It's likely around the 2.5 thou mark. Haynes says the gap should be between 0.015 and 0.023. So do you think I am able to rering? The machinist still wants to bore. Says the spec I found is way too much. If you thing about it 2.5 thou is about the thickness of a hair. Doubt it will matter much.
He also says the crank will need to be polished and go with 1 thou undersize bearings. Won't need to be ground so thats good.
Got the cam, rocker arms, lifters on the way. Figured new rebuilt lifter would be cheap insurance since I'm not sure if my lifters are good or not.
Delta cams made my cam. It is very similar to the comp cams 410 cam as seen below.
Now my other question is to do with the cam and pushrods.
The comp cams specs are as follows:
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 800-4,800
Intake Duration at 050 inch Lift: 201
Exhaust Duration at 050 inch Lift: 210
Duration at 050 inch Lift: 201 int./210 exh.
Advertised Intake Duration: 256
Advertised Exhaust Duration: 266
Advertised Duration: 256 int./266 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.465 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.500 in.
Valve Lift with Factory Rocker Arm Ratio: 0.465 int./0.500 exh. lift
Lobe Separation (degrees): 112
Intake Valve Lash: 0.000 in.
Exhaust Valve Lash: 0.000 in.
Computer Controlled Compatible: Yes
Grind Number: FV6 256HR-12
Quantity: Sold individually.
Camshaft, Hydraulic Roller Tappet, Advertised Duration 256/266, Lift
.465/.500, Ford, V6, Each
Delta cams changed a few things due to tooling constraints. They changed it to 203 X .450 intake 215 X .500 exhaust at 0.050 lift. So 2 thou more duration on intake, 5 thou more duration on exhaust, 15 thou less lift on intake and the same lift on exhaust.
Now my concern is the pushrod length. I think the stock length is 5.475". Comp cams recommends 5.550" I believe for their cam. Thats 75 thou overstock. Delta cams adds 50 thou to their rocker arms when they put the hardened tips in. They said they took 140 thou off and divided that by 2 for some reason (rocker ratio?). Thats 70 thou. 70 minus 50 is 20 thou too short. Can anyone recommend a size for me? I called smith bros today and they said they have had bad experiences when people do it this way by doing the math. The best way is to measure when it's together. I'm not sure how to do this. Would I be ok with a 5.525" pushrod? 50 thou overstock, about 30 thou extra for preload? Or should I wait and measure. My thoughts are if the 5.550" ones work for comp cams then maybe it would be fine for me too since the cam is basically the same. People have been using them along with the delta cams rocker arms as well I believe. Or I could order an adjustable pushrod to measure and then order the correct size.
The motor has 237,000 km and some lifter noise. I plan on doing new bearings, oil pump, seals, rings, gaskets, lifters, pushrods, rocker shafts, and a cam. I can still see factory cross hatching but there is a small ridge.
The gaskets will be felpro. Bearings are sealed power. I hear I should still use FORD lower intake, head gaskets, valve cover gaskets. Is this a good idea?
Machinist said the block is tapered 2.5 thou. Not out of round. He said that's on the upper limit. Haynes says the taper service limit is 0.010. The out of round limit is 1.5 thou and the service limit is 5 thou. There is no limit listed for the taper. It's likely around the 2.5 thou mark. Haynes says the gap should be between 0.015 and 0.023. So do you think I am able to rering? The machinist still wants to bore. Says the spec I found is way too much. If you thing about it 2.5 thou is about the thickness of a hair. Doubt it will matter much.
He also says the crank will need to be polished and go with 1 thou undersize bearings. Won't need to be ground so thats good.
Got the cam, rocker arms, lifters on the way. Figured new rebuilt lifter would be cheap insurance since I'm not sure if my lifters are good or not.
Delta cams made my cam. It is very similar to the comp cams 410 cam as seen below.
Now my other question is to do with the cam and pushrods.
The comp cams specs are as follows:
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 800-4,800
Intake Duration at 050 inch Lift: 201
Exhaust Duration at 050 inch Lift: 210
Duration at 050 inch Lift: 201 int./210 exh.
Advertised Intake Duration: 256
Advertised Exhaust Duration: 266
Advertised Duration: 256 int./266 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.465 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.500 in.
Valve Lift with Factory Rocker Arm Ratio: 0.465 int./0.500 exh. lift
Lobe Separation (degrees): 112
Intake Valve Lash: 0.000 in.
Exhaust Valve Lash: 0.000 in.
Computer Controlled Compatible: Yes
Grind Number: FV6 256HR-12
Quantity: Sold individually.
Camshaft, Hydraulic Roller Tappet, Advertised Duration 256/266, Lift
.465/.500, Ford, V6, Each
Delta cams changed a few things due to tooling constraints. They changed it to 203 X .450 intake 215 X .500 exhaust at 0.050 lift. So 2 thou more duration on intake, 5 thou more duration on exhaust, 15 thou less lift on intake and the same lift on exhaust.
Now my concern is the pushrod length. I think the stock length is 5.475". Comp cams recommends 5.550" I believe for their cam. Thats 75 thou overstock. Delta cams adds 50 thou to their rocker arms when they put the hardened tips in. They said they took 140 thou off and divided that by 2 for some reason (rocker ratio?). Thats 70 thou. 70 minus 50 is 20 thou too short. Can anyone recommend a size for me? I called smith bros today and they said they have had bad experiences when people do it this way by doing the math. The best way is to measure when it's together. I'm not sure how to do this. Would I be ok with a 5.525" pushrod? 50 thou overstock, about 30 thou extra for preload? Or should I wait and measure. My thoughts are if the 5.550" ones work for comp cams then maybe it would be fine for me too since the cam is basically the same. People have been using them along with the delta cams rocker arms as well I believe. Or I could order an adjustable pushrod to measure and then order the correct size.
