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 Post subject: 232 Valiant Project
PostPosted: Fri Nov 02, 2018 4:23 pm 
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2 BBL ''SuperSix''

Joined: Tue Oct 30, 2018 7:42 am
Posts: 14
Car Model*: Valiant 100
I have a 1968 Plymouth Valiant 100. It is the original 225 that has been bored out, stroked, and the motor and head have been machined (adding 7 cubic inches). It has a compression of 13:1. The valves have been pocket ported, with overlapping valves. The crank has been reground and balanced. Everything in the car is practically new. I am currently running the stock ignition control box, with a MSD Blaster 2 and distributor that I have had to rebuild several times. Initial timing is a 2*, while the mechanical swing is suppose to be 18*(9R), but I’m getting way more advancement. The carb is a Holley 390 cfm 4 barrel.

The issue that I’m having is that the car doesn’t have any power when accelerating. It feels if the motor is not ramping up the way it should. When I accelerate hard, the car backfires though the carb. It won’t go past 80, even though in the past it has made it to 120 no problem. It takes sometime to reach 80 (highway speed) without making it sput or backfire. What’s wrong with my car? :shock:


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 Post subject: Re: 232 Valiant Project
PostPosted: Fri Nov 02, 2018 6:34 pm 
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Joined: Thu Oct 17, 2002 7:27 pm
Posts: 11590
Location: Park Forest, Illinoisy
Car Model*: 68 Valiant
Too much compression and not enough timing.

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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 4:03 am 
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Joined: Fri Nov 01, 2002 5:02 pm
Posts: 1575
Location: Waterloo, Iowa
Car Model*: '23 T-bucket
'Zilla"s probably right, but I have a question. Are you running pump gas, on 13:1 CR?

Roger


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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 6:26 am 
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2 BBL ''SuperSix''

Joined: Tue Oct 30, 2018 7:42 am
Posts: 14
Car Model*: Valiant 100
I still need to go though the timing like Zilla said. I was concerned about over advancing the motor. I’ve read that the Slant 6 actually prefers higher advance. My issue or worry now is that the distributor is going to add too much mechanical advancement, unless the timing is part of the problem too.

Answering GTS225 question, I am running 91 octane for the pump. I used to add octane booster, which did help with everything (acceleration, idle, pinging, etc). I stopped using it because it was becoming expensive to fill up everytime. However, if that will help, I will go back to using it.

More info, I was running a 500cfm edlebrock about two months ago. I switched to the Holley 390 cfm because I thought I was getting too much air. I also changed out the mechanical fuel pump for an electric one. The mech had a 30 gph versus the electric had 32 gph.


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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 7:09 am 
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Joined: Mon Oct 21, 2002 11:08 am
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Location: Blacksburg, VA
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You need no more than 30-32 deg total timing at full mechanical advance. The 225 likes quite a bit LESS timing than typical V8s.

Lou

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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 8:10 am 
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Joined: Thu Oct 17, 2002 7:27 pm
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Location: Park Forest, Illinoisy
Car Model*: 68 Valiant
13:1 will not live on pump gas no matter how much octane booster is in it.

500 cfm is nowhere near too much air.

Again, how did you arrive at 13:1? :shock:

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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 8:51 am 
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Supercharged
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Joined: Sat Nov 27, 2004 8:03 pm
Posts: 4511
Location: IRWIN PA
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What are your cam specs and do you have or use an AFR/O2 gauge?

Greg

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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 10:06 am 
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2 BBL ''SuperSix''

Joined: Tue Oct 30, 2018 7:42 am
Posts: 14
Car Model*: Valiant 100
This is what I have from the machine shop:

Intake and Exhaust:
Lobe center sep = 111.4 cam deg
Valve overlap = 6.3 crank deg

Intake:
Valve opening = 3.2 (4*) BTDC (exactly)
Lobe center = 110.4 (107*) ATDC
Vavle closure = 45.2 ABDC
Duration = 228.4 crank deg
Max cam lift = .29311 in (.291)
Net valve lift = .43967 in
Lobe “area” = 24.41 in * deg
Lash = .012

Exhaust:
Valve opening = 46.5 BBDC
Lobe center = 112.5 BTDC
Valve closure = 3.2 ATDC
Duration = 229.7 crank deg
Max cam lift = .29272 in
Net valve lift= .43907 in
Lobe “area” = 24.49 in * deg
Lash = .012


The machinist left a note to the side stating: “in 1 to 3 deg advanced”


I am not using an AFR/ O2 gauge.


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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 10:30 am 
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Joined: Wed Oct 23, 2002 7:57 pm
Posts: 5474
Location: Waynesboro, Pa.
Car Model*: 65 Valiant 2Dr Post
Something is not right here. You have a small cam and huge compression ratio? Stroked engine? But only 7 cubic inch pick up. Please start with the basics of what you actually have and then this great group of people will help you sort through it.

Engine bored how much?
Engine stroked ? How much?
Head CC
Piston in the hole how much?
Quote:
with overlapping valves

What does this mean? Oversize valves?

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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 11:41 am 
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2 BBL ''SuperSix''

Joined: Tue Oct 30, 2018 7:42 am
Posts: 14
Car Model*: Valiant 100
I really appreciate all of the feedback from you guys.

I just emailed the machinist that did the job to provide more information. I will post later with more info about what was done (specs). Off the top of my head I recall having the motor and head milled. I want to say the minimum, but I’m not sure what that specifies. (.060 cut from the block and head?) The pistons are R&R piston set (diameter not known at the moment). The connecting rods were replaced with 198 cid 7” long rods. The block was bored and honed (diameter unknown atm). The camshaft is a Custom Delta High Performance camshaft. The motor also has custom length pushrod set of 10.185”


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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 5:35 pm 
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Joined: Wed Oct 23, 2002 7:57 pm
Posts: 5474
Location: Waynesboro, Pa.
Car Model*: 65 Valiant 2Dr Post
Ok that makes more sense. The long rods don't change the stroke but depending on the pistons usually raises the compression a lot. Machinist numbers will help quite a bit! We'll get her figured out and running tip top shortly! :D :D

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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 6:02 pm 
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Supercharged
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Joined: Sat Nov 27, 2004 8:03 pm
Posts: 4511
Location: IRWIN PA
Car Model*:
I hope one of the cam experts chimes in here. But that seems like a fairly small cam for this engine.

Greg

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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 7:17 pm 
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Joined: Thu Oct 17, 2002 7:27 pm
Posts: 11590
Location: Park Forest, Illinoisy
Car Model*: 68 Valiant
Greg Ondayko wrote:
I hope one of the cam experts chimes in here. But that seems like a fairly small cam for this engine.

Greg


Barely bigger than a stocker. Also wondering why he has pushrods .200" longer than stock too.

You know me, that's a lawnmower cam. :mrgreen:

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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 10:05 pm 
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2 BBL ''SuperSix''

Joined: Tue Oct 30, 2018 7:42 am
Posts: 14
Car Model*: Valiant 100
Still no word from the machinist.
However, I was digging through some of notes and research that I have, and I believe I found the camshaft part number. The only reason why I was able to recognize is by the fact it has 340 valve springs that work with the cam. PN P4286679 (cam pn)
Here are the links for the sources:

http://www.slantsix.org/articles/racing ... ant63.html

http://www.mopar1.us/camchart.html


Zilla, that lawnmower comment made me laugh out loud. :mrgreen: I am still waiting for a response from the machinist, but if I remember correctly it was about the opening of the valves? Please correct/inform me if I’m wrong.


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 Post subject: Re: 232 Valiant Project
PostPosted: Sat Nov 03, 2018 10:31 pm 
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Joined: Thu Oct 17, 2002 7:27 pm
Posts: 11590
Location: Park Forest, Illinoisy
Car Model*: 68 Valiant
I would be most interested in knowing how far in the hole the pistons are and how much dish they have. A 7" rod gets the piston pretty high up, and if he cut the block and head you may have a "0" deck height motor. With flat tops you could be at 12:1 or better, especially if he used a thin head gasket.

My old junk 7" rod motor had 2.2 turbo pistons in it and they were -.018" down with an 18cc dish. With a stock chamber size that gave a touch higher than 9.5:1.

Realistically, you are going to have to work on your distributor. 2* is nowhere near enough initial to get that thing to run. You will have to weld up your slots to limit total advance and maybe run without the vacuum can.

That cam is a mild upgrade, I have a rebuilt motor with one in it. I will pull it out before the motor ever goes in one of my cars. :oops:



:lol: :lol: :lol: :lol: :lol: :lol:

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