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Vintage Reconditioning a 142 to streetable...

RR

New member
Joined
May 15, 2003
Location
Northern CA
condition.

I just acquired a solid 1970 142 with B20 and twin SU carbs with manual transmission.

I have rebuilt several 240/740/940's, but this is my first 142. I have replaced all the fluids after inspecting the car. No rust, bushes are tired and cleaning up interior bits, etc.

It has 400k miles though doesn't show. Engine ran roughly when it rolled off the trailer, but after a few years sitting wouldn't stay running.

Here is my question...I sent off the carbs and now back, but I feel the need to pull the head and inspect the pistons while having the top end rebuilt. Or maybe just a compression check and run it...

However, are there solid sources for new valvetrain parts besides IPD? I know VP and CVR...are there one stop shops I am missing?

My budget on this one is limited to <1k, but I feel like the valves and springs and pushrods ought to be replaced as well as a minor shave.

What am I not thinking about on this solid roller pushrod runner?

Cheers and thanks in advance, Rick
 

JohnMc

PV Abuser
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May 10, 2004
Location
St. Louis
I'd just do a compression test first and then plan what to do based on the results.

Oh, and adjust the valves first, and take note if any are loose or tight (and tight exhaust valves are a sort of a warning sign for receding exhaust valve seats).

Unless you really want to zing it to 7500 rpm, not much of a reason to replace the valve springs. And no real reason to replace pushrods unless you're shaving so much off the head you use up the rocker adjustments (not likely), or you're using different lifters that are a different length. Solid SBC lifters are a somewhat common part used in place of OEM lifters, more for availability than anything else (and for a while, OEM lifters had a bad reputation for failing and taking out cam lobes).

On the plus side, if you do feel like whipping the head off it's so very incredibly simple on the old pushrod motors.
 

RR

New member
Joined
May 15, 2003
Location
Northern CA
I'd just do a compression test first and then plan what to do based on the results.

Oh, and adjust the valves first, and take note if any are loose or tight (and tight exhaust valves are a sort of a warning sign for receding exhaust valve seats).

Unless you really want to zing it to 7500 rpm, not much of a reason to replace the valve springs. And no real reason to replace pushrods unless you're shaving so much off the head you use up the rocker adjustments (not likely), or you're using different lifters that are a different length. Solid SBC lifters are a somewhat common part used in place of OEM lifters, more for availability than anything else (and for a while, OEM lifters had a bad reputation for failing and taking out cam lobes).

On the plus side, if you do feel like whipping the head off it's so very incredibly simple on the old pushrod motors.

Thank you for your thoughts. Rick
 

RR

New member
Joined
May 15, 2003
Location
Northern CA
I'd just do a compression test first and then plan what to do based on the results.

Oh, and adjust the valves first, and take note if any are loose or tight (and tight exhaust valves are a sort of a warning sign for receding exhaust valve seats).

Unless you really want to zing it to 7500 rpm, not much of a reason to replace the valve springs. And no real reason to replace pushrods unless you're shaving so much off the head you use up the rocker adjustments (not likely), or you're using different lifters that are a different length. Solid SBC lifters are a somewhat common part used in place of OEM lifters, more for availability than anything else (and for a while, OEM lifters had a bad reputation for failing and taking out cam lobes).

On the plus side, if you do feel like whipping the head off it's so very incredibly simple on the old pushrod motors.

John, is it acceptable to do compression check with the cabs off the engine? I will have the gas line off, of course and the coil wire pulled.

Whate are good compression numbers for a pushrod of this vintage?

Thanks again, Rick
 

JohnMc

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No problem at all doing a compression test with the carbs off. You need to hold the throttles open if they're still attached, same thing.

As for the numbers... it's sort of hard to put up any specific numbers. BEcause there are all sorts of variables. How fast it cranks, what HG it's using, what cam and how it's degreed, valve adjustments, etc. And differences in how different gauges read. All in all you're mostly just looking for nothing catastrophically low (like... below 120?) but most importantly, how consistent they are across the cylinders. If there are problems, they will very rarely be evenly represented on all the cylinders.

You should probably have a B20B motor, with something like 9.5:1 CR. You probably won't see anything too high on the gauge. Squirt a little oil in each cylinder, crank it around a few times, and test again and see if it goes up noticeably. If it does, that's a sign the rings are not doing too well.
 

RR

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May 15, 2003
Location
Northern CA
No problem at all doing a compression test with the carbs off. You need to hold the throttles open if they're still attached, same thing.

As for the numbers... it's sort of hard to put up any specific numbers. BEcause there are all sorts of variables. How fast it cranks, what HG it's using, what cam and how it's degreed, valve adjustments, etc. And differences in how different gauges read. All in all you're mostly just looking for nothing catastrophically low (like... below 120?) but most importantly, how consistent they are across the cylinders. If there are problems, they will very rarely be evenly represented on all the cylinders.

You should probably have a B20B motor, with something like 9.5:1 CR. You probably won't see anything too high on the gauge. Squirt a little oil in each cylinder, crank it around a few times, and test again and see if it goes up noticeably. If it does, that's a sign the rings are not doing too well.

Thanks again John...that all makes sense.

Cheers
 

JohnMc

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Location
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Oh, and I was going to say, with these cars having been around for half a century, you never know what mix of parts it has on it at this point. Could still be all original or correct replacement B20B parts, but could also be a mix of other fairly compatible parts as well.

But yeah, adjust the valves first, then a compression test.

If you haven't done a valve adjustment on these yet, here are a few quick tips:
1) .016 - .019 clearances, but as you're doing it, check for tight exhaust valves. There are no hardened valve seats on these old pushrod motors (unless they were added later) - and they were intended to be used with leaded gas. If driven gently, they may maintain a work hardened surface for a long time without lead in the gas, but valve work on the seats, or hard use, and that surface wears off and the valves start wearing their way through the cast iron seats at a quicker pace.
2) Rule of nines - you want to set the lash with the lobe pointing away from the lifter, but you can't see that. But the cam is symmetrical - when one lobe is up, you know another one is in the opposite position. You can tell by the 'Nines' rule. Going from the front, if #1 valve is open, you can set #8 (1+8 = 9). If #2 is open, you can set #7 (2+7 = 9). And just move on down the line until you get all 8 done.
 

RR

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May 15, 2003
Location
Northern CA
Oh, and I was going to say, with these cars having been around for half a century, you never know what mix of parts it has on it at this point. Could still be all original or correct replacement B20B parts, but could also be a mix of other fairly compatible parts as well.

But yeah, adjust the valves first, then a compression test.

If you haven't done a valve adjustment on these yet, here are a few quick tips:
1) .016 - .019 clearances, but as you're doing it, check for tight exhaust valves. There are no hardened valve seats on these old pushrod motors (unless they were added later) - and they were intended to be used with leaded gas. If driven gently, they may maintain a work hardened surface for a long time without lead in the gas, but valve work on the seats, or hard use, and that surface wears off and the valves start wearing their way through the cast iron seats at a quicker pace.
2) Rule of nines - you want to set the lash with the lobe pointing away from the lifter, but you can't see that. But the cam is symmetrical - when one lobe is up, you know another one is in the opposite position. You can tell by the 'Nines' rule. Going from the front, if #1 valve is open, you can set #8 (1+8 = 9). If #2 is open, you can set #7 (2+7 = 9). And just move on down the line until you get all 8 done.

That is great help here, and that is the next step in the engine bay. As time is an issue, I may farm this out...maybe not. I have a buddy who has done some head work on my 240 and I miss seeing him and allowing me to refresh the heads. Money at machine shop not that much an issue.

This car will stay with me till the end, so I may splurge for the head work of the pistons are good.

Also, can I test each cylinder compression with all of the plugs out at the same time for convenience?

Thanks again, Rick
 

JohnMc

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Sure, but that gets into the variability of compression tests. It's going to crank faster with all the plugs out, which will tend to have slightly higher readings. But like I said, worry a bit less about the actual number, and just see if there pretty consistent across all 4. And after you do the 'dry' test, follow it up with a 'wet' test after putting in a teaspoon of oil.

Doing the valves is simple, takes about 15 unhurried minutes, and it's something that an old pushrod motor needs at periodic intervals. That and gapping the points and setting the timing.
 

RR

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May 15, 2003
Location
Northern CA
Sure, but that gets into the variability of compression tests. It's going to crank faster with all the plugs out, which will tend to have slightly higher readings. But like I said, worry a bit less about the actual number, and just see if there pretty consistent across all 4. And after you do the 'dry' test, follow it up with a 'wet' test after putting in a teaspoon of oil.

Doing the valves is simple, takes about 15 unhurried minutes, and it's something that an old pushrod motor needs at periodic intervals. That and gapping the points and setting the timing.

Very good, will consider this. Will do the compression test with all the plugs out, as my very busy sweetie will be turning the key.

Would static timing set at 16 degrees advance, (right side of timing mark) be ok? The ignition is from B20E, as a matter of fact, and all of those bits plus wires are new.

Btw, I did my homework on the timing marks/settings...I just moved the crank mark to +16 degrees.

Thanks again, RR
 
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dl242gt

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On a high mileage pushrod engine. I'd want to inspect the cam gear for wear as that can catastrophically fail and leave you stranded. You can get a basic idea of the wear by slightly turning the motor over and watching the distributor. You can rock the crank back and forth slightly to see how far it moves before it moves the distributor. If it's a lot of slack then the cam gear is worn.
 

JohnMc

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Very good, will consider this. Will do the compression test with all the plugs out, as my very busy sweetie will be turning the key.

Would static timing set at 16 degrees advance, (right side of timing mark) be ok? The ignition is from B20E, as a matter of fact, and all of those bits plus wires are new.

Btw, I did my homework on the timing marks/settings...I just moved the crank mark to +16 degrees.

Thanks again, RR

A B20E distributor probably has a vacuum retard on it, you wouldn't want to hook that up to the vac port on the carbs. It sort of does the opposite of what the vacuum gizmo on a B20B distributor does. It just retards the timing at idle, which was done for emissions testing back in the early 70's (which was done only at idle), retards the timing a little, lowers NOX production, but as soon as you open the throttle a little, the retard goes away (after making the throttle response a little sluggish) and it's back to making all the NOX it was going to anyhow. But it passed the idle sniff test, so that's all that mattered. B20B vacuum advance was there to advance timing a bit at higher RPM's - the vac port on the carbs acts differently.

Back in the day, I never really paid too much attention to the degree timing, I just properly adjusted the points, and then would just advance the timing until I got a slight sprinkling of accelerator tip-in pinging, then retard it a tiny bit and leave it. The engine liked as much advance as I could get away with (given the CR/gas octane/temps/etc). That said, 16 degrees seems like a bit more than normal? I thought it was supposed to be more around 10 degrees (set at idle, vac disconnected).
 

JohnMc

PV Abuser
300+ Club
Joined
May 10, 2004
Location
St. Louis
On a high mileage pushrod engine. I'd want to inspect the cam gear for wear as that can catastrophically fail and leave you stranded. You can get a basic idea of the wear by slightly turning the motor over and watching the distributor. You can rock the crank back and forth slightly to see how far it moves before it moves the distributor. If it's a lot of slack then the cam gear is worn.
That's one of the Achilles' heels of the pushrod redblocks. That pressed fiber timing gear. At 400K it's certainly been replaced before, but how long ago?

Another fun thing the fiber gears can do is become separated from the steel center that's bolted to the camshaft. That happened on my PV's original B18 motor not terribly long after I got it running again after it had sat for about 17 years. I think perhaps a lack of heat cycles let some moisture sit in the motor, which may have weakened the fiber gear?

Either way, that's the main problem point on the engine, closely followed by wiped cam lobes. Use a high-zinc engine oil on these old things. The valve lifters themselves are not directly oiled, they just get some drainage splattering down from the pressure fed rocker shaft above. And the cam lobes themselves, as far as I can tell, just get some 'casual' oiling from oil seeping past the lifters and possibly windage or direct splatter from the spinning crank/rod bearings. But not really enough oil to make them bulletproof. High zinc oils are hard to find these days because they're not friendly to cars with catalytic converters (that burn oil, ahem). So you'll have to find either some additive (I use Lucas engine break-in ZDDP additive) or some 'racing' or diesel oil that has higher ZDDP levels.
 

RR

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May 15, 2003
Location
Northern CA
On a high mileage pushrod engine. I'd want to inspect the cam gear for wear as that can catastrophically fail and leave you stranded. You can get a basic idea of the wear by slightly turning the motor over and watching the distributor. You can rock the crank back and forth slightly to see how far it moves before it moves the distributor. If it's a lot of slack then the cam gear is worn.

Good point, thanks! Though if I change the cam gear I am probably going to drop in a hotter cam...then...

Cheers
 

RR

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Location
Northern CA
A B20E distributor probably has a vacuum retard on it, you wouldn't want to hook that up to the vac port on the carbs. It sort of does the opposite of what the vacuum gizmo on a B20B distributor does. It just retards the timing at idle, which was done for emissions testing back in the early 70's (which was done only at idle), retards the timing a little, lowers NOX production, but as soon as you open the throttle a little, the retard goes away (after making the throttle response a little sluggish) and it's back to making all the NOX it was going to anyhow. But it passed the idle sniff test, so that's all that mattered. B20B vacuum advance was there to advance timing a bit at higher RPM's - the vac port on the carbs acts differently.

Back in the day, I never really paid too much attention to the degree timing, I just properly adjusted the points, and then would just advance the timing until I got a slight sprinkling of accelerator tip-in pinging, then retard it a tiny bit and leave it. The engine liked as much advance as I could get away with (given the CR/gas octane/temps/etc). That said, 16 degrees seems like a bit more than normal? I thought it was supposed to be more around 10 degrees (set at idle, vac disconnected).

Thank you.
 

RR

New member
Joined
May 15, 2003
Location
Northern CA
That's one of the Achilles' heels of the pushrod redblocks. That pressed fiber timing gear. At 400K it's certainly been replaced before, but how long ago?

Another fun thing the fiber gears can do is become separated from the steel center that's bolted to the camshaft. That happened on my PV's original B18 motor not terribly long after I got it running again after it had sat for about 17 years. I think perhaps a lack of heat cycles let some moisture sit in the motor, which may have weakened the fiber gear?

Either way, that's the main problem point on the engine, closely followed by wiped cam lobes. Use a high-zinc engine oil on these old things. The valve lifters themselves are not directly oiled, they just get some drainage splattering down from the pressure fed rocker shaft above. And the cam lobes themselves, as far as I can tell, just get some 'casual' oiling from oil seeping past the lifters and possibly windage or direct splatter from the spinning crank/rod bearings. But not really enough oil to make them bulletproof. High zinc oils are hard to find these days because they're not friendly to cars with catalytic converters (that burn oil, ahem). So you'll have to find either some additive (I use Lucas engine break-in ZDDP additive) or some 'racing' or diesel oil that has higher ZDDP levels.

Thanks again John
 

JohnMc

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Joined
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Location
St. Louis
Good point, thanks! Though if I change the cam gear I am probably going to drop in a hotter cam...then...

Cheers

Don't go too hot with SU's. They get confused by reversion on a really snorty cam. And the heads don't flow all that well (almost all due to the exhaust ports), so a really hot cam might raise the power band up to a range where the head can't flow. Compromised low end power in exchange for high end power that the head doesn't allow.

But for sure, the 'C' grind cam the B20B probably has (it's almost certainly been replaced a time or two at 400K miles so who knows) isn't doing anyone any favors. A stock B20E (D grind) or B20F (K grind) cam will perk up an otherwise stock carbed B20 (or B18) very nicely. Maybe an Isky VV71/IPD 'Street Perf' cam.

Well, assuming it's a manual trans. The horrible BW35 automatic doesn't really like revs, so it's pointless to get a zippier motor going in front of one of those buzz killers.
 
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