redwhitekat

Ok my 74 coupe has smoke coming out of ehaust not terrible but visable at times should I buy new heads or should I rebuilt my original ??

billla

The questions always become how much do you want to spend, and how much (more) power do you want?

SB64

What kind of mtr S/B how many mile on mtr. may just need a valve job. Smoke when you start car??

redwhitekat

Yes I got the l82 motor 80000 miles it does smoke at start up I have had the valve seals replaced not really looking for power just not to smoke

7t9l82

find a good shop that specializes in heads if you can,guides , 3 angle valve job and some bowl work will take care of the problem and help the power a bit.

billla

The place to start here is with a leak-down and compression test - this will tell you where the "leak" is and how bad it is. I suspect it's the guides, but that's the purpose of the test. The tools are pretty cheap from Harbor Freight (not great tools but "good enough) and using them is fairly easy if a bit of work.


Any more a quality valve job is knocking on $500. A shop that can touch up the short radius of the intake runners and maybe cleaning up under the valves for a mild port might be worth the investment - just be sure they know what they're doing.


Taking a little time and measuring how far the pistons are down in the bore would let you select the right head gasket for ideal quench and a little CR boost.


Finally, a cam swap at the same time is worth thinking about "while you're in there". The L82 cam isn't bad, but a more modern grind around the same specs will make more power. It also lets you change out the timing chain...a very good idea.

redwhitekat

Thanks I just did the timing chain not sure about the cam I just wanted it to run nice and clean
I'm just wondering to you car guys if it makes sense rebuilding my heads or get new ones there's lots of options and prices on amazon etc I'm sure those heads come complete

lvmyvt76

OK, so if you buy new heads, they will probably be higher performance: if you have the heads redone, they will have all the correct bolt holes for everything to bolt back up, will better than they are now(if done correctly), will be original to the motor(if original to it now). How can we tell you what to do? It is also how deep are your pockets are, get pricing on head work before, compare to cost of new heads, then make a decision yourself.


Off course check with the wife to make sure she is happy with your decision. Also, Christmas is coming up REAL soon.

redwhitekat

lol yes I was just checking the pros and cons

garygnu

do a leak down test,and pull the valve covers and look at the valve seals.you can replace valve seals with the heads in the car .

redwhitekat

Ill do a compression test valve seals were replaced

billla

In this case, the leak-down will tell you more than the compression test - including where the blowby is happening.

TedH

I had my DART heads rebuilt for $600 at a local speed shop. You can get the stock heads rebuilt for $500 or less and that is with all new valve guides and 3-angle valve cut.

I paid extra for DART guides and even had steel valve seat inserts put in my heads so you may pay less.

Be sure to have them magnafluxed to check for cracks.

lvmyvt76

I would find a couple of engine shops that have good reputations from others and talk to the owner and machine man, asking questions first, then get an estimate. Make sure and talk with speed heads about who they recommend. The estimate should be written detailing what is going to be done, and what happens if they find a surprise. GOOD LUCK!!

63mako

That cam was originally installed in the L46 with 11 to 1 compression. The L82 dropped compression to 9 to 1 with no change in cam design. This drops power over 8% across the entire RPM range not just peak plus a DCR reduction for more power loss. That combined with poor factory head flow restricts power drastically. If your looking at spending $500+ on a valve job, your leakdown test is good, and your cam and lifters are ok I would suggest upgrading to a set of Dart SHP 64 cc 180 heads and 1.6 rockers with a performance distributor curve. This gets you new aluminum heads, weight reduction, way better flow numbers, compression more aligned with the cam specs, and lift and duration to compliment the head flow. Exhaust is the next bottleneck and should be upgraded. This will cost you about $500-600 more plus exhaust but I would guess 20-30% power increase across the board.

Amorget

+1 to that... if your only concern is the valve seals, no reason to rebuild the entire head. Just replace the valve seals with the heads on the car.

redwhitekat

Good ideas I already have a magnaflow ehaust system with lg headers

redwhitekat

I already replaced the valve seals that didn't change a thing

Amorget

I am unsure what you are looking at in your heads then... you should be looking at your piston rings.

TedH

If the guides are worn, seals will not keep the oil out of the combustion chamber.

what type of seals did you install? If you have stock heads with single spring with damper, you can install the one-piece umbrella seals which are a step up from the basic o-ring seal.

Another question: Any valvetrain noise? Am asking as my guides were so worn that I was getting high rpm rattle in the valve train. If no noticeable noises from valvetrain, umbrella seals may work (if you don'thave them already).