Is the Toyota Valve Adjustment Spec good for any cam on a 2F? I've been getting conflicting info on widening the gap. Is this because they are assuming a valve grind @ the same time? Thanks.
Valve Adjustment with RV Cam Grind
- Thread starter thetoyotaman
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no the valve adjustment is not the same. when you installed a new cam the spec sheet will tell you what the valves need to be set at
Did you buy the cam already with the RV Grind or did you send your cam out to be reground? As Ken said, your cam should have come with valve adjustment specs. As an FYI, Delta recommends .014/.014 with their 250S grind but have also suggested to bring it to stock specs the valvetrain is too noisy at their specs.
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- #4
I sent my cam to Delta for a regrind. No specs sent with it, just a receipt for DEL-859-KC. Thanks.
Did you save the box? Delta prints the recommended valve adjustment on the box. Please keep me posted about this. I noticed my valvetrain is a bit noisier after the rebuild with the Delta reground cam and wanted to know what others' experience was. Also let me know how much vacuum you're pulling.
RV cams do not pull as much vacuum as a stock cam. At idle anyway. Hard to compare exactly, but my old 1.5F would pull 20"/Hg at a 750 RPM idle. Rebuilt 2F block (bored .50 over) with unknown reground RV cam and 1.5F head pulls 15 or 16" at the same idle.
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- #8
It was not on the box.
I got my 74F cam reground to the 250s from Delta and I received no clearance specs. Knowing no different I've been running the stock clearances. Hope I don't burn a valve. I didn't get my free t-shirt as promised either. I do love that low rpm grunt though.
I would call them and ask what they recommend for your grind.
You won't come even close to burning a valve at stock specs with the 250s cam. The engine will pull more vacuum using that cam with a looser valve train, so that may be a reason why they recommend their .014/.014 clearances for the 250s grind.
Good to know. I'm pulling the same amount of vacuum and wanted to make sure that was normal for this cam before trying to hunt down vacuum leaks. I wasn't expecting 20" with a lumpier cam, but I wasn't sure if 15-16 was normal for this cam, either.
You got me wondering. I have a cam purchased from Downey, and I have always adjusted per FSM. I just pm'd Jim to see if I should be doing something else
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It will be a little while before I get it running. I have the whole drivetrain out and am rebuilding the motor, H41 tranny, and fixing previous owner stuff. I have the majority of it done now, just the little things.
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Just an update, started motor for the first time the other day. I broke the cam in for 30 minutes. After adjusting the carb and timing to stock, I am pulling 9 in of vacuum. Seemed a little low and I am just under 5000 feet here. Did some inquiring and research. Bumped the timing to around 13 degrees using the lower window as a reference and am getting 10.5 in and running far better. Bumped it as far as it would go and am just under 12 now. I need to drive it and see if I have any pinging to try to find the sweet spot and use this as a reference. I'm wondering if the vacuum will naturally go up as the motor breaks in.
I imagine the vacuum would increase as the rings seat, but not enough to notice.
Don't forget to re-adjust your valves and re-torque your manifolds after the first run-in. I re-torque the head bolts too, but there is some controversy about that...
Snug down the carb too.
Sounds like you must have a vacuum leak or your idle mixture is way off if you're only pulling 9" with stock timing. What idle speed did you have it running at? Did you adjust the idle mixture?
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- #18
If I max out the timing for max vacuum I do get pinging so I went back to 13 degrees. Idle mixture does best at 4.5 turns out. Idle speed set to 650 rpm. It did have a bad vacuum leak before I rebuilt her and it doesn't act like it has one anymore.
Just took a little drive on the interstate. Gutless wonder at this point. Couldn't keep 75mph. Is that just the stock gearing and 36's at this point?
Just took a little drive on the interstate. Gutless wonder at this point. Couldn't keep 75mph. Is that just the stock gearing and 36's at this point?
75mph on 36s is just too damn fast. At least your engine knows that.
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- #20
I have to say I am really pleased with the Downey suspension and tires. It drives very smooth on the highway.